Study of the Carbonaceous Aerosol Over Gazipur City: Identification and Assessment of Sources

STUDY OF THE CARBONACEOUS AEROSOL OVER GAZIPUR CITY: IDENTIFICATION AND ASSESSMENT OF SOURCES

A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF

MASTER OF PHILOSOPHY (M PHIL.) IN PHYSICS

Submitted by

MOHAMMED MOZAMMEL HOQUE Student No: 102806-P Session: 2010-11

DEPARTMENT OF PHYSICS DHAKA UNIVERSITY OF ENGINEERING & TECHNOLOGY, GAZIPUR GAZIPUR-1707

DECEMBER, 2016 DECLARATION

It is hereby declared that the dissertation entitled “Study of the Carbonaceous Aerosol over Gazipur City: Identification and Assessment of Sources” is an original work and has been prepared as well as presented by myself. I further declare that this dissertation has not been submitted to elsewhere for awarding of any academic degree.

Mohammed Mozammel Hoque Student No: 102806-P Session: 2010-11 Department of Physics Dhaka University of Engineering & Technology, Gazipur. Gazipur-1707.

APPROVAL OF SUPERVISOR

This is to certify that the dissertation entitled “Study of the Carbonaceous Aerosol over Gazipur City: Identification and Assessment of Sources” has been carried out by Mohammed Mozammel Hoque, Student No: 102806-P, Session: 2010-2011, Department of Physics, Dhaka University of Engineering & Technology, Gazipur 1707, Bangladesh. To my knowledge this dissertation has not been submitted to elsewhere for awarding of any academic degree.

It may be mentioned here that two research papers have already been published in peer reviewed journals out of this thesis work.

Supervisor (Dr. Syed Jamal Ahmed) Professor Department of Physics Dhaka University of Engineering & Technology, Gazipur-1707, Bangladesh

DEDICATED

MY BELOVED PARENTS

Acknowledgements

All praises are for the Almighty Allah for his infinite mercy and blessings.

I would like to express deepest sense of gratitude to my supervisor Professor Dr. Syed Jamal Ahmed, Head, Department of Physics, Dhaka University of Engineering and Technology, Gazipur, for his encouragement and suggestions throughout the progress of my research work.

I would also like to express gratitude to my co-supervisor Dr. Bilkis Ara Begum, CSO and head, Chemistry Division, Atomic Energy Center, Dhaka (AECD) for her indispensable guidance and valuable suggestions to carry out the research work.

I am grateful to all faculty of the Physics Department specially to Professor Dr. Md. Kamal-Al-Hassan and Professor Dr. Abu Talib Md. Kaosar Jamil, for their constructive criticism, stimulating encouragement and suggestions in many ways.

I gratefully acknowledge the Department of Environment (DoE) for giving me the opportunity for sampling at the Continuous Air Monitoring Stations (CAMS) and Atomic Energy Center, Dhaka (AECD) for laboratory facilities. In this connection I would like to thank Engr. Mrinal Kanti Saha, CAMS, Gazipur, DoE and Mrs. Lipi Sarkar, Scientific Assistant, Chemistry Division, AECD for helping me in various ways.

I acknowledge the Ministry of Education, Bangladesh to permit me to carry out this research work and the Ministry of Science and Technology, Bangladesh for giving me fellowship for this work.

Finally I am thankful to my wife and kids for giving me all kinds of support during the research work.

December, 2016 The Author

ABSTRACT

The ambient air of Dhaka and Gazipur are polluted by different particulate matters (PM) as well as gaseous pollutants. Sampling was done at a semi residential site, Joydebpur (CAMS- 4 site), Gazipur city and a traffic hot spot site (HS), Farmgate (CAMS-2 site), Dhaka, during December, 2013 to February, 2014 to observe the concentrations of black carbon (BC) and particulate matters for both coarse (PM10) and fine (PM2.5) fractions in the air of these cities. At the same time the meteorological parameters of the sampling sites such as temperature, humidity, wind speed, wind direction, rainfall, visibility etc. was observed. Sampling was performed by Air Matrices Mini Vol. sampler.

At Gazipur site, in December 2013, it was observed that, the average concentrations of PM10, 3 3 3 PM2.5 and BC were 189.46 µg/m , 146.71 µg/m and 80.171 µg/m , respectively. The ratio of

PM2.5 and PM10 showed that the average PM2.5 mass was about 78 % of the PM10 mass.

Whereas, at the same time in Dhaka site the average concentrations of PM10, PM2.5 and BC 3 3 3 were 291 µg/m , 123 µg/m and 31.47 µg/m , respectively and the average PM2.5 mass was about 42.27 % of the PM10 mass.

In January 2014, at Gazipur site the average concentrations of PM10, PM2.5 and BC were 3 3 3 found 200.43 µg/m , 129.78 µg/m and 65.67 µg/m , respectively. The ratio of PM2.5 and

PM10 showed that the average PM2.5 mass was about 65 % of the PM10 mass. Whereas, at the 3 same time in Dhaka site the average concentrations of PM10, PM2.5 and BC were 209 µg/m , 3 3 126 µg/m and 25.71 µg /m , respectively and the average PM2.5 mass was about 61 % of the

PM10 mass.

In February 2014, at Gazipur site the average concentrations of PM10, PM2.5 and BC were 3 3 3 found 163.57 µg/m , 119.94 µg/m and 74.17 µg/m , respectively. The ratio of PM2.5 and

PM10 showed that the average PM2.5 mass was about 73 % of the PM10 mass. Whereas, at the 3 same time in Dhaka site the average concentrations of PM10, PM2.5 and BC were 208 µg/m , 3 3 97 µg/m and 26.47 µg/m , respectively and the average PM2.5 mass was about 50 % of the

PM10 mass.

During the sampling period (December, 2013 to February, 2014) the average concentrations 3 3 3 of PM10, PM2.5 and BC were found 185 µg/m ,132.65 µg/m and 73.1 µg/m , respectively at Gazipur, whereas those are 237µg/m3, 117 µg/m3 and 27.7 µg/m3, respectively in Dhaka. At the same time the average readings of relative humidity, visibility, temperature, rain fall and wind speed were 69.65 %, 2.76 km, 19.150C, 0.02 cm and 0.95 m/s, respectively. Though Farmgate (CAMS-2 site) of Dhaka is a very busy traffic point and Joydeppur of Gazipur

(CAMS-4 site) is a semi-residential area, the concentration of PM2.5 in the air of Gazipur was found higher than that of Dhaka during the sampling period and the daily average of PM2.5 and PM10 for both the cities always exceeds the Bangladesh National Ambient Air Quality 3 3 Standard (BNAAQS, 65 µg/m for PM2.5 and 150 µg/m for PM10). It was observed that concentrations of PM and BC were higher with lower value of relative humidity and wind speed. During winter season brick kiln emission and long range transports increase the particulate matter in the air of Gazipur compared to that of Dhaka. Besides, there is an impact of indoor air pollution on the air quality of Gazipur city.

CONTENTS

Page No Abstract i-ii Contents iii-iv List of figures v-vi List of tables Vii List of abbreviations viii-ix CHAPTER- 1: INTRODUCTION 1-5 1.1 General Introduction 1 1.2 Objectives with specific aims and possible outcome 4 1.3 Importance of the study 4 1.4 Organization of the thesis 5 CHAPTER- 2: THEORETICAL ASPECTS AND LITERATURE REVIEW 6-24 2.1 Air pollution 6 2.2 Sources of air pollution in Bangladesh 7 2.3 Air pollutants 12 2.4 Effects of air pollution 13 2.5 Carbonaceous aerosol 15 2.6 Black carbon 16 2.7 Particulate matter 17 2.8 Review of earlier works 20 CHAPTER-3: EXPERIMENTAL DETAILS 25-37 3.1 Air sampling 25 3.2 Description of the sampler 26 3.3 Sampling sites 29 3.4 Sampling 33 3.5 Determination of black carbon 36 3.6 Meteorological conditions of the sampling sites 37

iii

CHAPTER-4: RESULTS AND DISCUSSION 38-69 4.1 Particulate mass concentrations 38

4.1.1 PM2.5 mass concentration 38

4.1.2 PM10 mass concentration 40

4.1.3 Ratio of the concentrations of PM2.5 and PM10 42 4.1.4 Sources of pollutants 46 4.1.5 Comparisons of PM mass concentrations between present data 48 and previous data for Farmgate, Dhaka. 4.2 Concentrations of black carbon 51

4.2.1 Fraction of black carbon in PM2.5 53 4.3 Variation of PM and BC with respect to meteorological condition 54 4.3.1 Effect of wind direction 55 4.3.2 Effect of wind speed 55 4.3.3 Effect of humidity 59 4.3.4 Effect of rainfall 63 4.3.5 Effect of temperature 63 4.4 Traffic volume at the sampling sites 65 CHAPTER –5: CONCLUSIONS 70-71 5.1 Conclusions 70 5.2 Recommendations 71 5.3Suggestions for future work 71 CHAPTER-6: REFERENCES AND APPENDICE 72-86 References 72-77 Appendix-I National Ambient Air Quality Standards for Bangladesh 78 Appendix-II Gaseous composition of dry air 79 Appendix-III Experimental data obtained from the study 80 Appendix-IV: News paper reports in support of study 84 Appendix-V Publications from the thesis. 85

LIST OF FIGURES

Figure No. Figure Title Page No. Figure 2.1 Brick kilns are one of the major sources of air pollution. 8 Figure 2.2 Dust in urban areas. 9 Figure 2.3 Emission from construction activities 10 Figure 2.4 Various source of black carbon 17 Figure 2.5 Size of particulate matter 18 Figure 3.1 Schematic diagram of the sampling head of Air matrices PM 26 sampler Figure 3.2 PM Pre-separator and filter holder assembly 28 Figure 3.3 CAMS sites in Bangladesh 29 Figure 3.4 Map of sampling site, CAMS-2 (Farmgate, Dhaka) 30 Figure 3.5 Gazipur (Joydebpur) rail station and CAMS-4 site 31 Figure 3.6 Map of sampling site (CAMS-4, Joydebpur, Gazipur) 32 Figure 3.7 Placing the Mini Vol. sampler at the Gazipur sampling site. 33 Figure 3.8 Teflon filters (a) Before sampling, (b) After Sampling 34 Figure 3.9 Smoke stain reflectometer 36 Figure 3.10 Schematic diagram of the reflectance measurement 36 technique Figure 4.1 Concentrations of PM2.5 in the air of Dhaka and Gazipur 39

Figure 4.2 Concentrations of PM10 in the air of Dhaka and Gazipur 41

Figure 4.3 Ratio of the concentrations of PM2.5 and PM10 in the air of 44 Gazipur

Figure 4.4 Ratio of the concentrations of PM2.5 and PM10 in the air of 44 Dhaka Figure 4.5 Average monthly PM data (μg/m3) in the air of Dhaka 50 during winter Figure 4.6 Average monthly PM data (μg/m3) in the air of Dhaka 50 during rainy season. Figure 4.7 Concentrations of black carbon in the air of Dhaka and 52 Gazipur

Figure 4.8 Fraction of BC in PM2.5 in the air of Gazipur and Dhaka 54

Figure 4.9 Variation of PM2.5 with respect to wind speed in Gazipur. 56

Figure 4.10 Variation of PM2.5 with respect to wind speed in Dhaka. 56

Figure 4.11 Variation of PM10 with respect to wind speed in Gazipur. 57

Figure 4.12 Variation of PM10 with respect to wind speed in Dhaka. 57 Figure 4.13 Variation of black carbon with respect to wind speed in the 58 air of Gazipur Figure 4.14 Variation of black carbon with respect to wind speed in the 59 air of Dhaka Figure 4.15 Variation of black carbon with respect to humidity in the air 60 of Gazipur Figure 4.16 Variation of black carbon with respect to humidity in the air 60 of Dhaka

Figure 4.17 Variation of PM2.5 with respect to humidity in the air of 61 Gazipur

Figure 4.18 Variation of PM10 with respect to humidity in the air of 61 Gazipur

Figure 4.19 Variation of PM2.5 with respect to humidity in the air of 62 Dhaka

Figure 4.20 Variation of PM10 with respect to humidity in the air of 62 Dhaka Figure 4.21 Average numbers of Motor vehicles per hour through station 68 road, Gazipur at day time Figure 4.22 Personal vehicle fleet in Dhaka 69

Figure 4.23 Two-stroke three wheelers through Station Road, Gazipur 69

LIST OF TABLES

Table No. Table Title Page No. Table 2.1 Major sources of criteria air pollutant 11 Table 2.2 Common atmospheric pollution sources and their pollutants 13 Table 2.3 Health impact of the criteria air pollutants 14 Table 2.4 Emission factors of PM, BC and OC from diesel vehicles 15 Table 2.5 Current Air Quality Standards 18 Table 2.6 Particulate concentrations at different parts in Bangladesh 20

Table 4.1 Concentrations of PM2.5 in Gazipur (Joydebpur) and Dhaka 40 (Farmgate)

Table 4.2 Concentrations of PM10 in Gazipur (Joydebpur) and Dhaka 42 (Farmgate)

Table 4.3 Ratio of the concentrations of PM2.5 and PM10 in the air of 45 Gazipur and Dhaka: Table 4.4 Source contributions: 2005-2006, for a semi-residential site 47 (Dhaka) Table 4.5 Concentrations of PM found in the present study and 48 Emission Standards. Table 4.6 Average monthly PM data (μg/m3) in the air of Dhaka during 49 winter Table 4.7 Concentration of BC (μg/m3) in the air of Dhaka and 53 Gazipur: Table 4.8 Meteorological data during the sampling period 64 Table 4.9 Number of registered motor vehicles in Bangladesh (year 66 wise) Table 4.10 Number of registered motor vehicles in Dhaka (year wise) 67 Table 4.11 Average number of motor vehicles per hour through 68 station road, Gazipur at day time

vii

LIST OF ABBREVIATIONS

AECD Atomic Energy Centre Dhaka AQMP Air Quality Management project BARC Bangladesh Agricultural Research Council BC Black Carbon BMD Bangladesh Meteorological Department BNAAQS Bangladesh National Ambient Air Quality Standard BRTA Bangladesh Road Transport Authority CAMS Continuous Air Monitoring Station CASE Clean Air and Sustainable Environment CCN Cloud Condensation Nuclei CORDS Chronic Obstructive Respiratory Diseases. DoE Department of Environment DRI Desert Research Institute EC Elemental Carbon EPA Environmental Protection agency FID Flame Ionization Detector GoB Government of Bangladesh HAPs Hazardous Air Pollutants. IBA Ion Beam Analysis IMPROVE Interagency Monitoring of Protected Visual Environment Km-ph Kilo meter per hour LAC Light Absorbing Carbon MM Measured Mass MOUDI Micro-Orifice Uniform Deposit Impactors NDIR Non-Dispersive Infrared Radiation OC Organic Carbon

OCprim Primary Organic Carbon

OCsec Secondary Organic Carbon

viii

LIST OF ABBREVIATIONS

PAHs Polycyclic Aromatic Hydrocarbons PCB Poly-Chlorinated Biphenyl PDG Proton Induced X-ray Emission PESA Particles Elastic Scattering Analysis PIGE Proton Induced γ-ray Emission PM Particulate Matter

PM2.5 Particulate Matter (less than 2.5 micrometers in diameter)

PM10 Particulate Matter (between 2.5 and 10 micrometers in diameter) PMF Positive Matrix Factorization PMT Photo Multiplier Tube POA Primary Organic Aerosol RM Reconstructed Mass SOA Secondary Organic Aerosol SPM Suspended Particulate Matter. SSA Single Scattering Albedo TC Total Carbon TOR/TOT Thermal Optical Reflectance/Transmittance UFPs Ultra-Fine Particles (less than 1 micrometers in diameter) USEPA United States Environmental Protection Agency UV Ultra Violet VOCs Volatile Organic Carbons WHO World Health Organization µg/m3 Microgram per cubic meter

CHAPTER-1 INTRODUCTION

1.1 General introduction Air pollution receives one of the prime concerns in Bangladesh, primarily due to rapid economic growth, industrialization and urbanization with associated increase in energy demands. Lacks of implementation of environmental regulations are contributing to the low air quality of most of the cities of Bangladesh. Air pollutants produced in any air shed are not completely confined, but at time trespassing all the geographical boundaries, hence do not remain only the problem of urban centers, but spread and affect rural areas. In order to reduce pollutant concentrations in the atmosphere, pollution sources must be identified, emission should be estimated and effective management strategies should be developed. Global warming is now a burning issue in the present world. This global warming is mainly due to carbon emission which generally known as carbonaceous particles in the air. Carbonaceous aerosols (Atmospheric particulate carbon) consist of fine particles, mostly less than 1μm in diameter, which are usually classified as either black carbon (BC), essentially, but not identically the same as elemental carbon (EC) or organic carbon (OC), in which the carbon is bonded to other elements. Black carbon or elemental carbon often called as soot is the primary light-absorbing aerosol and organic carbon is the less-absorbing carbonaceous aerosol.

Motorized transport vehicles are suspected to be the single largest contributor of air pollution in the big cities of Bangladesh. According to Bangladesh Road Transport Authority (BRTA), the annual growth in the number of motorized vehicles is about l0%. Although the growth in the number of motorized vehicles in the major cities has been about 10% for last several years, the contribution from vehicles has not increased linearly with vehicular numbers. The majority of private cars that ran on gasoline have been converted to CNG. Some diesel buses and trucks have also been converted to CNG largely because of the fuel price differential. However, because of electrical power problems, there are many diesel powered generators. In addition, increasing economic activity has generated a high demand for construction materials including fired bricks. To meet this enhanced demand, there have been an increased number of brick kilns around

Dhaka and Gazipur. The important sources of particulate matter (PM) in Gazipur are diesel-powered vehicles, two stroke engine gasoline vehicles and brick kilns.

During recent decades the increasing concern about the variation and properties of atmospheric pollutants in the environment around the world have been investigated by scientist. The concentration of atmospheric particles specially, carbonaceous particle is one of the most important indices for assessing air pollution as well as climate change.

Many studies have shown the considerable impact of PM2.5 on human health, global climate change and visibility reduction. Carbon is one of the elements in atmospheric particulate matter which occupies about 20-60% of PM2.5 concentration [1] and mainly exists in the form of organic carbon (OC) and elemental carbon (EC). OC and EC in particulate matter play an important role in global climate effects, visibility degradation and human health. Carbonaceous aerosol is produced due to the use of high rates of coal and bio-fuels.

Particulate matter pollution (fine and course) is the bad concern in major cities of Bangladesh. The main contributors of air pollution are motor vehicles, brick kilns, diesel generators and industries. In recent years much research interest has been focused on atmospheric particles due to their influence on climate and adverse health effects [2-7]. Dhaka, the eighth largest city in the world, has witnessed a rapid growth of urban population in recent times. As a result, the number of motor vehicles increased significantly in Dhaka and major traffic intersections in the city have turned to hot spots for air pollution from vehicular emissions. Fine particulate matter with aerodynamic diameter less than 2.5 µm is a widespread air pollution problem [8]. Particle sources (from coal and biomass burning in brick field) impacts are contributing haze at urban and semi-urban areas of Bangladesh. Gazipur, a new city corporation is considered as one of the industrially developed city in Bangladesh. High particulate matter (PM) levels and poor visibility in winter time have become a serious problem there. Coal and biomass burning in brick field, vehicle exhaust, industrial and residential emissions contribute to the ambient PM in this city. During winter season brick kiln goes in operation. The pollution due to vehicles and brick kilns is then expected to be high during winter. In Bangladesh during winter season a lot of coal and fire wood are used in brick kiln, from where carbonaceous particles are emitted into the air.

Carbonaceous aerosols (Atmospheric particulate carbon) are composed of organic carbons (OC) and elemental carbons (EC). Fine atmospheric particulate matter (PM) having aerodynamic diameters less than 2.5 µm (PM2.5), affects visibility, human health and earth’s climate. Ambient particulate matter (PM), specially in urban and highly industrial areas, contains an important fraction of carbonaceous materials. In recent years much research interest has been focused on atmospheric carbonaceous particles due to their influence on climate and adverse health effects [2-4]. Although significance of carbonaceous aerosols in atmospheric and environmental process is pronounced, our knowledge, specially in Bangladesh, on their concentration, sources and formation mechanism are inadequate. Rapid industrialization and economic development occurred in Dhaka and Gazipur cities during the recent years, which increase the emission of various pollutants. Bilkis et al. have studied the source identification of carbonaceous aerosols (PM2.5) during winter months in Dhaka city [8] and also investigated atmospheric aerosol at urban and semi-urban areas in Bangladesh by positive matrix factorization [9]. They found that the contribution from EC fraction at Farmgate (urban area site) was less compared to Aminbazar (semi urban site). Because at Farmgate only the city vehicles run on road and during the day time mostly 80 % of the vehicles are of duel-fueled engine (CNG & gasoline). Particle sources (from Coal and biomass burning in brick field) contribute haze at urban and semi-urban areas of Bangladesh.

Gazipur, a new city corporation is considered as one of the industrially developed city in Bangladesh. High PM levels and poor visibility in winter time have become a serious problem there. Coal and biomass burning in brick field, vehicle exhaust, industrial and residential emissions contribute to the ambient PM in this city. In this work, the concentration and sources of carbonaceous particles will be assessed and compared with the previous results of other cities. This work is the measurement on the pollution sources and their contributions on the air quality of Gazipur sadar area due to the contribution of different types of vehicles and brick kilns those are not yet reported. In this work, sampling was performed by gravimetric method. The concentration and sources of particulate matter (PM2.5 and PM10) in two locations, Farmgate and Joydebpur of Dhaka and Gazipur cities, respectively will be addressed and compared.

1.2 Objectives with specific aims and possible outcome a) To assess the black carbon (BC) and particulate matter (PM2.5 and PM10) in the air of Gazipur City and to identify the possible sources of carbonaceous materials b) To investigate the relation of the concentrations of PM with respect to distance. c) To determine the percentage of BC to the total fine particulate mass and to find the

ratio of BC and PM2.5 in the air. d) To study the role of different meteorological parameters on PM pollution.

1.3 Importance of the study Analysis of the carbonaceous particles is an important area of investigation in the environmental science. It is also necessary to understanding the impact of the atmospheric pollution on human health, vegetation, regional and global climate change. This type of investigation will contribute to develop the fundamental knowledge in this field and will help to develop the necessary monitoring of air pollution.

Recently, air pollution has received priority among environmental issues in Asia, as well as in other parts of the world. Exposure to air pollution is the main environmental threat to human health in many towns and cities. There are two major sources of air pollution in Bangladesh, vehicular emissions and industrial emissions. However, these are mainly concentrated in the cities. Particulate emission is mainly responsible for increased death rate and respiratory problems for the urban population. This problem is acute in Dhaka being the capital of the country and also the hub of commercial activity. Dhaka is a major, cultural, and manufacturing center. The common types of industries in and around the periphery of Dhaka are ready-made garment manufacturing, jute, tanneries, textile, tea processing, fertilizer, cement, paper and pulp, chemicals and pesticides, food and sugar, pharmaceuticals, petroleum refinery, distillery, rubber, plastics, and brick manufacturing, assembling buses, trucks, and motorcycles, assembling radios and televisions. Air of Dhaka is being polluted day by day very badly. The other urban areas i.e. Chittagong, Khulna, Bogra and Rajshahi have much lesser health problem related to urban air pollution. The ambient atmospheric conditions have progressively deteriorated due to the unprecedented growth in numbers of motor vehicles, and continuous housing and industrial development. Gazipur, a newly developing city of Bangladesh is facing rapid industrialization and construction work which results air pollution. In this study, a comparative figure is shown between the air quality of Dhaka and Gazipur.

This work will give a comprehensive pollutant picture of Gazipur city compared to that of Dhaka city. Information obtained in this study will allow evaluation of the air quality and develop further pollution control strategies.

1.4 Organization of the thesis Chapter-1: Introduction In this chapter a brief introduction of air pollution concern in Bangladesh due to particulate matter concentration is described. This chapter also incorporates in understanding the objectives and importance of the present study.

Chapter-2: Theoretical aspects and literature review In this chapter the theoretical aspects of air pollutions, air pollutants and sources of air pollution are described. Also the particulate matter pollution in the air of Dhaka and Gazipur city are described with review of some earlier researches performed to monitor particulate matter at different places in home and abroad.

Chapter-3: Experimental details In this chapter air sampling, sampling site and different experimental measurements are discussed in details.

Chapter-4: Results and discussion In this chapter the evaluation of particulate matter and black carbon concentrations in the air at Dhaka and Gazipur are discussed.

Chapter-5: Conclusions In this chapter the study is summarized and future work is suggested.

Chapter-6: References All references of each chapter are given in this part.

Appendices In this part NAAQS data, Gaseous composition of dry air and all experimental data of this study are tabulated.

Publications Two published papers from this study is added in this part.

CHAPTER-2 THEORETICAL ASPECTS AND LITERATURE REVIEW

2.1 Air pollution Air pollution has become an extremely serious problem for the modern industrialized world. Air pollution may be defined as any atmospheric condition in which certain substances are present in such concentrations that may produce undesirable effects on human and ecosystem. These substances include gases (sulphur dioxide, nitrogen oxides, carbon monoxides, hydrocarbons, etc.), particulate matters (smoke, dust, fumes, aerosols, etc), radioactive materials and many others. Air pollution may have harmful effects on living things and materials. It may interfere with biochemical and physiological processes of plants to an extent, which ultimately leads to yield losses [10]. Air pollution was earlier considered as a local problem around large point sources. But due to use of tall stacks and long range transport of pollutants, it has become a regional problem. The transboundary nature of pollutants was clearly evident when areas remote from sources of air pollution also showed higher concentrations of air pollutants. Uncontrolled use of fossil fuels in industries and transport sectors has led to the increase in concentrations of gaseous pollutants such as SO2, NOx, etc. Air pollution is an undesirable change in the physical, chemical or biological characteristics of air. In other word it is the contamination of the indoor or outdoor environment by any chemical, physical or biological agent that changes the natural characteristics of the atmosphere. Household combustion devices, motor vehicles, industrial facilities and forest fires are common sources of air pollution. Pollutants of major public health concern include particulate matter, carbon monoxide, ozone, nitrogen dioxide and sulfur dioxide. Outdoor and indoor air pollution cause respiratory and other diseases, which can be fatal. Air pollution, especially in winter in the large cities of Bangladesh, is a major environmental hazard. The impact of poor ambient air quality on human health, agricultural production and damage to materials has been well documented in developing and developed countries. Governments of all developed countries have been very active in controlling air pollution in order to ensure a good quality of life for their citizens. Developing countries like Bangladesh have also taken note of the air pollution issues, and often guided by the multinational agencies like the World Bank (WB), Asian

Development Bank (ADB), United Nations Environment Programme (UNEP), have taken measures or have made plans to reduce and control air pollution.

2.2 Sources of air pollution in Bangladesh In order to control air pollution, it is necessary to understand the sources of the pollution, since all pollution control approaches aim to reduce emissions in order to control ambient concentration of pollutants.

Motor Vehicles: Combustion of fuels in motor vehicles is, undoubtedly, the most important source of air pollution in the largest of the urban centers. Fuel combustion not only produces fine particulates directly, which have severe health effects, but also emits NOx and SOx, which are important precursors to producing further particulates in the atmosphere [11]. NOx and HC emitted from vehicles can also undergo transformation in the atmosphere to produce ozone (as well as a range of other secondary pollutants), another pollutant with direct adverse health impacts. Also, vehicles emit closer to the human population and thus have a direct effect on human health in urban areas. Bangladesh does not have any vehicle manufacturing industry and all the vehicles are imported from abroad. Among the personal vehicle fleet, most are pre-used cars imported from Japan. Since these vehicles were originally built to strict Japanese emissions standards, mostly Euro IV equivalent, their emission performances are quite good as found in the road side measurements by the Department of Environment (DoE). An important parameter in particulates from motor vehicles is the sulphur content in the fuel. High sulphur content can be particularly harmful for diesel vehicles.

Biomass Burning: The World Health Organization (WHO) estimates that 2.4 billion people worldwide rely on burning biomass fuels (e.g., fuel wood, animal dung, crop residues) for cooking and heating their homes. Biomass is extensively used in rural areas of Bangladesh, primarily for cooking. Biomass contributes to more than half of the total primary energy needs in Bangladesh. Biomass burning, especially in traditional cooking stoves, results in significant air pollution, which is harmful especially to the women and young children who often spend most of their time in the kitchen with a high level of particulates concentration. In rural Bangladesh, majority of the people rely on solid biomass fuel; and firewood, crop residue, dung, and tree leaves accounts for about 97 % of total household energy use[12]. Outdoor biomass burning generally takes place during

7 the winter after a crop harvest. This adds to the winter fogs to create dense smog in rural areas of Bangladesh. While immediate health impact may not be of serious concern, smog can be a driving hazard and has been blamed for a quite a few road accidents and fatalities in the highways of Bangladesh. It is also a fairly common practice to burn refuse, which can be potentially harmful, especially if there are other harmful elements in the refuse (e.g. PVC, heavy metal, batteries etc.). Burning of accumulated dry leaves is also fairly common in cities and rural areas during the winter (as a means of disposal of these “solid wastes”). While localized effects can be significant in cities, the impact in rural areas and meson-scale effects may not be that large.

Brick Kilns: Brick kilns are a major source of air pollution throughout Bangladesh (Figure 2.1). Brick kilns are major sources of PM, SOx, CO, VOC (VOCs are precursors to O3) and acidic gases (e.g. HF, HCl etc.). Brick making is also one of the largest GHG emissions source in Bangladesh, with large CO2 emissions from the combustion of coal and wood.

Figure 2.1: Brick kilns are one of the major sources of air pollution.

Construction and Vehicular Activities: Dust is one of the major problems in most urban areas (Figure 2.2) and some rural areas in Bangladesh, especially during the dry seasons (i.e. winter, spring and late autumn). While coarse suspended particulates are not as lethal as their finer counterparts, they can still be a health hazard, especially increasing incidences of morbidity among the population. Construction and vehicular activities primarily give rise to dust in urban areas (Figure 2.3). Large urban metropolises (Dhaka and Chittagong and, to a lesser extent, the divisional and the district head quarters) have benefited from a boom in the real estate sector, but this also equates to an increase in construction activities. Since there are no specific guidelines or rules on storage and transport of construction materials, it is very common that the construction sites are all very dusty. Even the roads catering for the construction traffic are also dusty because there are no requirements of covering the construction material during transport. In addition, most of the construction (especially excavation and soil transport which are particularly dust generating) take place during the winter, which is dry and further conducive to air pollution.

Figure 2.2: Dust in urban areas.

Figure 2.3: Emission from construction activities

Road traffic also adds to the air pollution in addition to its contribution through combustion exhausts. Vehicular movements on unpaved roads generate a large amount of coarse suspended matter. Even on paved roads, which are often of poor quality and suffer surface damages during the monsoon, vehicular movements generate coarse particulates during the winter. Traffic also causes re suspension of the settled dust on the road. Transport of bulk material in vehicles without proper cover can also result in spills and dust. Roads are also responsible for emissions during its construction and maintenance phases through open processing of asphalts. In large cities, these activities now take place at nights and thus direct exposure to non-construction people is limited. In the next few years, some very large transportation projects will take place in Dhaka, which would be responsible for additional dust emissions and increase short term acute exposure to air pollution.

Industries: While the brick industry requires a separate section because of its large contribution to air pollution, contribution from other industrial sources are not negligible. The major polluting industries in this regard are the cement, steel, parboiling rice mills, and glass plants. All three are directly linked to building and infrastructure construction (as is brick), which is a natural consequence of the state of growth in Bangladesh. Since

10 such growth is expected in the future, it is important to control emissions from these sources in order to keep the air quality at a reasonable level. There are currently gaseous emissions standards governing emissions from these industries, but enforcement is so poor that only a few people are aware of their existence.

Power Sector: Although electricity utilities are a major source of air pollution in many developed and developing countries, their contribution to air pollution in Bangladesh has not been large. As opposed to the USA, Australia, China or India, where coal is the major primary source to produce electricity, Bangladesh has only one coal-fired power plant. Most of its electricity is produced from natural gas, which is much cleaner than coal, both in terms of local air pollution and global air pollution. At present, a major air pollution concern in the power sector is the small, particularly because of the prevalence of natural gas power plants, but numerous small to medium diesel generators currently supplement the infrequent grid electricity supply in the residential, industrial and commercial sectors. These small diesel generators currently do not have to meet any emissions standards and their total emissions may be significant (no reliable data available), and they also emit much closer to the people in comparison to large scale power plants, with potentially large health impacts. Diesel generators can also be a large growth sector in the future if reliable electricity supply cannot be ensured. Table 2.1 presents major sources of criteria air pollutants.

Table 2.1: Major sources of criteria air pollutants (Source: USEPA)

Pollutant Sources Carbon Monoxide (CO) Motor vehicle exhaust, kerosene, power plants with internal combustion engines or wood/biomass burning stoves.

Sulphur Dioxide (SO2) Coal-fired power plants, brick kilns, petroleum refineries, sulphuric acid manufacture, and smelting sulphur containing ores.

Nitrogen Dioxide (NO2) Motor vehicles, power plants, and other industrial, commercial, and residential sources that burn fuels (e.g. diesel generators).

Ozone (O3) Vehicle exhaust and certain other fumes (hydrocarbons). Formed from other air pollutants in the presence of sunlight. Lead (Pb) Metal refineries, lead smelters, battery manufacturers, iron and steel producers. Particulate Matter (PM) Diesel engines, motor vehicles, power plants, brick kilns, industries, windblown and road dust, wood/ biomass stoves, open burning.

2.3 Air pollutants Air pollutants are any gas, liquid or solid substance that have been emitted into the atmosphere and are in high enough concentrations to be considered harmful to the environment, or human, animal and plant health. Pollutants emitted directly into the air are called "primary pollutants". "Secondary pollutants" are formed in the air, when they react with other pollutants. Ground-level ozone is an example of a secondary pollutant that forms when nitrogen oxides (NOx) and volatile organic compounds (VOCs) react in the presence of sunlight. Depending on the type and amount emitted, these pollutants may affect air quality at the local, regional, and/or global scale. For example, smoke from woodstoves or backyard burning and motor vehicle exhaust are pollutant mixtures that affect air quality in our neighborhoods and communities, and inside our homes. Smoke from forest fires or ground-level ozone can cover an entire region. Long-lasting pollutants can contribute to serious global problems, such as ozone depletion and climate change. Some air pollutants are described below: Carbon Monoxide (CO): It is formed by fuel combustion from vehicles and engines. It reduces the amount of oxygen reaching the body’s organs and tissues; aggravates heart disease, resulting in chest pain and other symptoms.

Ground-level Ozone (O3): It is a secondary pollutant formed by chemical reaction of volatile organic compounds (VOCs) and NOx in the presence of sunlight. Decreases lung function and causes respiratory symptoms, such as coughing and shortness of breath, and also makes asthma and other lung diseases get worse. Lead (Pb): Formed at smelters (metal refineries) and other metal industries; combustion of leaded gasoline in piston engine aircraft; waste incinerators (waste burners), and battery manufacturing. Damage the developing nervous system, resulting in IQ loss and impacts on learning, memory, and behavior in children. Cardiovascular and renal effects in adults and early effects related to anemia.

Nitrogen Dioxide (NO2): It is emitted from fuel combustion (electric utilities, big industrial boilers, vehicles) and wood burning. Worsens lung diseases leading to respiratory symptoms, increased susceptibility to respiratory infection. Particulate Matter (PM): This is formed through chemical reactions, fuel combustion (e.g., burning coal, wood, diesel), industrial processes, farming (plowing, field burning), and unpaved roads or during road constructions. Short-term exposures can worsen heart or lung diseases and cause respiratory problems. Long-term exposures can cause heart or lung disease and sometimes premature deaths.

Sulfur Dioxide (SO2): SO2 comes from fuel combustion (especially high-sulfur coal); electric utilities and industrial processes as well as natural occurrences like volcanoes. Aggravates asthma and makes breathing difficult. It also contributes to particle formation with associated health effects. Table 2.2 presents the common atmospheric pollution sources and their pollutants.

Table 2.2: Common atmospheric pollution sources and their pollutants

Category Source Emitting pollutants

Agriculture Open burning Suspended particulate matter, carbon monoxide, volatile organic compounds etc.

Mining and Coal mining; crude oil and gas Suspended particulate matter, sulphur dioxide, oxides of quarrying production; stone quarrying nitrogen, volatile organic compounds etc.

Power Electricity; gas; steam Suspended particulate matter, sulphur dioxide, oxides of generation nitrogen, carbon monoxide, volatile organic compounds, sulphur trioxide, lead etc.

Transport Combustion engines Suspended particulate matter, sulphur dioxide, oxides of nitrogen, carbon monoxide, volatile organic compounds, lead etc.

Community Municipal incinerators Suspended particulate matter, sulphur dioxide, oxides of service nitrogen, carbon monoxide, volatile organic compounds, lead etc.

2.4 Effects of air pollution Health effects: Short-term health effects include headache, asthma and emphysema. Long-term health effects can include chronic respiratory disease, lung cancer, heart disease, and even damage to the brain, nerves, liver, or kidneys. Inhalable particulate matters are responsible for respiratory and cardiovascular morbidity.

Long-term exposure to PM2.5 is associated with an increase in the long-term risk of 3 cardiopulmonary mortality by 6-13 % per 10 μg/m of PM2.5 [13-16]. It is estimated that approximately 3 % of cardiopulmonary and 5 % of lung cancer deaths are attributable to PM globally. In the European region, this proportion is 1-3 % and 2-5 %, respectively [17]. A recent study indicates that the burden of disease related to ambient air pollution

13 may be even higher. The study estimated that in 2010, ambient air pollution, as annual

PM2.5, accounted for 3.1 million deaths and around 3.1 % of global disability-adjusted life years [18]. Black carbon is a form of ultrafine particulate matter, which when released in the air causes premature human mortality and disability. It is estimated that from 6,40,000 to 4,900,000 premature human deaths could be prevented every year by utilizing available mitigation measures to reduce black carbon in the atmosphere [19]. Even relatively low exposure concentrations of Black Carbon have an inflammatory effect on the respiratory system of children [20].

Climate impacts: Black carbon absorbs incoming solar radiation, perturb the temperature structure of the atmosphere, and influence cloud cover [21]. The increased surface temperature would decrease the snow cover and further increase surface albedo [22]. Emissions of black carbon are the second strongest contribution to current global warming, after carbon dioxide emissions [23-24]. Table 2.3 shows the health impact of the criteria air pollutants

Table 2.3: Health impacts of the criteria air pollutants (source: USEPA)

Pollutant Health Effects Other Welfare Effects Carbon Headaches reduced mental alertness, heart Contribute to the formation of some Monoxide(CO) attack, cardiovascular diseases, impaired secondary pollutants. fetal development, and death. Sulphur Dioxide Eye irritation, wheezing, chest tightness, Contribute to the formation of acid

(SO2) shortness of breath, lung damage. rain, visibility impairment, plant and water damage, aesthetic damage. Nitrogen Susceptibility to respiratory infections, Contribute to the formation of smog,

Dioxide (NO2) irritation of the lung and respiratory acid rain, water quality deterioration, symptoms (e.g. cough, chest pain, global warming, and visibility difficulty breathing). impairment.

Ozone (O3) Eye and throat irritation, coughing, Plant and ecosystem damage. Material respiratory tract problems, asthma, lung (rubber) damage damage, leading to premature mortality. Lead (Pb) Anemia, high blood pressure, brain and Affects animals and plants, affects kidney damage, neurological disorders, aquatic ecosystems. cancer, lowered IQ. Particulate Eye irritation, asthma, bronchitis, lung Visibility impairment, atmospheric Matter (PM) damage, cancer, cardiovascular effects, deposition, aesthetic damage. leading to premature mortality.

2.5 Carbonaceous aerosol An aerosol is a colloid of fine solid particles or liquid droplets, in air or another gas. Aerosols can be natural (such as; fog) or artificial (such as haze, dust, particulate air pollutants and smoke). The aerosol relating to, containing, or composed of carbon or rich in carbon are called carbonaceous aerosols. Carbonaceous aerosols are one of the most important ubiquitous materials in the atmosphere, formed by all types of combustion processes. They comprise about 10-50% of the tropospheric particulates with particularly high levels found in the urban atmosphere. Carbonaceous aerosols consist of fine particles, mostly less than 1 μm in diameter, which are usually classified as either black carbon (BC), essentially, but not identically the same as elemental carbon (EC) [25], or organic carbon (OC), in which the carbon is bonded to other elements. Black carbon or elemental carbon, often called as soot is the primary light-absorbing aerosol and Organic Carbon is the less-absorbing carbonaceous aerosol. Carbonaceous aerosols (BC and organics) absorb and scatter solar radiation. Therefore, BC is increasingly recognized as an important contributor to global climate change. Observations have shown that even trace amounts of BC can result in a large atmospheric solar absorption, which reduces substantially the solar radiation reaching the surface.

Sources of carbonaceous aerosols Carbonaceous aerosols are primarily emitted from all types of combustion processes: fossil fuels, biomass, bio-fuels and industrial processes. Different combustion processes emit different amounts of carbonaceous aerosol as a consequence of the efficiency of the combustion process. Diesel engines produce more carbonaceous particulate matter than spark-ignition engines resulting from differences in the mode of fuel injection and ignition. Incomplete combustion of the fuel is responsible for production of carbon soot or BC in particulate matter. This carbonaceous soot is formed in the center of the fuel spray where the air/fuel ratio is low. Table 2.4 shows the emission factors of PM, BC and OC from different types of diesel vehicles. Table 2.4: Emission factors of PM, BC and OC from diesel vehicles [26].

Conditions Unit PM OC BC Heavy duty diesel vehicles g km-1 0.408 0.133 0.165 Medium and light heavy duty g km-1 0.153 0.059 0.105

Medium Duty g km-1 0.185 0.036 0.056

The emission factors of carbonaceous aerosols for unleaded vehicles are reported to be almost ten times lower than diesel vehicles; on the contrary leaded gasoline vehicles have shown increased PM emission factors but not any significant change in emission factors of carbonaceous aerosols [27]. The PM emissions from two-stroke engines are higher than from four-stroke engines due to escape of unburned fuel and lubricating oil from the cylinder.

2.6 Black carbon Carbonaceous particles are elemental carbon or black carbon and organic carbon. Chemically, black carbon or BC is a component of fine particulate matter (PM ≤ 2.5 µm in aerodynamic diameter). Black carbon consists of pure carbon in several linked forms. It is formed through the incomplete combustion of fossil fuels, bio-fuel, and biomass, and is emitted in both anthropogenic and naturally occurring soot. Black carbon causes human morbidity and premature mortality [28]. In climatology black carbon is a climate forcing agent. Black carbon warms the Earth by absorbing sunlight and heating the atmosphere and by reducing albedo when deposited on snow and ice (direct effects) and indirectly by interaction with clouds, with the total forcing of 1.1 W/m2 [29]. Black carbon stays in the atmosphere for only several days to weeks, whereas carbon dioxide (CO2) has an atmospheric lifetime of more than 100 years [30].

Sources of black carbon

The majority of black carbon emissions are from developing countries and this trend is expected to increase. The largest sources of black carbon are Asia, Latin America, and Africa. China and India together account for 25-35 % of global black carbon emissions. Black carbon emissions from China doubled from 2000 to 2006. Existing and well-tested technologies used by developed countries, such as clean diesel and clean coal, could be transferred to developing countries to reduce their emissions. Approximately 20 % of black carbon is emitted from burning bio-fuels, 40% from fossil fuels, and 40 % from open biomass burning. The majority of soot emissions in South Asia are due to bio-fuel cooking [31] whereas in East Asia, coal combustion for residential and industrial uses plays a larger role. Figure 2.4 shows the primary sources of BC emissions and the processes that control the distribution of BC in the atmosphere and its role in the climate system (Source: Based on US EPA 2012, and Bond et al., 2013).

Figure 2.4: Various sources of black carbon

2.7 Particulate matter Particulate matter pollution generally consists of a mixture of very small particles of dust, pollen, ash, soot, metals and other various solid and liquid chemicals found in the atmosphere. All particles that are suspended into the air are known as PM, which are the main pollutants of the air. Carbonaceous particles are the most important particles in PM. Fine and ultrafine particles can reside the environment for long time and can travel for long distance. Ultrafine particles especially carbonaceous particles have the main responsibilities for global warming as well as climate change."Particulate matter", also known as particle pollutant or PM, is a complex mixture of extremely small particles and liquid droplets. Particle pollution is made up of a number of components, including acids (such as nitrates and sulfates), organic chemicals, metals, and soil or dust particles. The size of particles is directly linked to their potential for causing health problems. Particle pollution can be classified into two categories; fine particles and coarse particles. Particles less than 2.5 micrometers in diameter are called "fine" particles. These

17 particles are so small that, they can be detected only with an electron microscope. Sources of fine particles include all types of combustion, including motor vehicles, power plants, residential wood burning, forest fires, agricultural burning, and some industrial processes. Particles between 2.5 and 10 micrometers in diameter are referred to as “coarse". Sources of coarse particles include crushing or grinding operations, and dust (Figure 2.2 and Figure 2.3) stirred up by vehicles traveling on roads. Figure 2.5 shows the relative size of particulate matter and human hair (source: US EPA).

Figure 2.5: Size of particulate matter.

The history of air quality management in Bangladesh is relatively recent. Ambient air quality standards were first introduced in Bangladesh in 1997 under the environmental conservation rules (ECR) 1997. The current Air Quality Standard (AQS) for suspended

Particulate Matter (SPM), Coarse Particulate Matter (PM10) and Fine Particulates (PM2.5) is presented in Table 2.5.

Table 2.5: Current Air Quality Standards (Source: ADB 2006)

Pollutant Averaging Bangladesh WHO guideline US standard time standard (μg/m3) (μg/m3) (μg/m3)

Suspended Particulate 8 hour 200 - - Matter (SPM) Coarse Particulates Annual 50 20 - (PM10) 24 hour 150 50 150 Fine Particulates Annual 15 10 15 (PM 2.5) 24 hour 65 20 35

Although Bangladesh was one of the first few countries in Asia to enact a PM2.5 standard for ambient air, the achievements on the compliance of this and other particulate related standards are poor. Consistent and coherent source for time series information on SPM or PM concentrations in ambient air are also not available, since CAMS of the DoE at Shangshad Bhaban in Dhaka started operating in 2002 (partially operative during 2007- 2010); the other CAMS in Dhaka (at BARC) has been operating since 2008. A CAMS has also been operating in Chittagong since 2006 and two more in Khulna and Rajshahi since 2008. There are also several satellite monitoring stations (SAMS) at Narayanganj, Tongi, Sylhet and several locations in Dhaka, where only PM samples have been collected sporadically. Atomic Energy Centre Dhaka (AECD), since 1993, and Bangladesh University of Engineering and Technology (BUET) have also been taking snapshot measurements of the ambient PM concentrations over time. There are issues regarding the quality assurance in the data generated and also breaks in the time dimension. The DoE also takes occasional measurements of SPM at different towns in Bangladesh.

Because of larger emission sources (higher motorization rate, larger population, larger number of industries) and high impact possibilities (large population exposure), Dhaka is the most important city in terms of air pollution. The ambient PM concentrations become higher during November to March. The air quality is further aggravated during the winter due to the seasonal operations of the many thousand brick kilns, both near Dhaka and throughout the country. Also, temperature inversions during the winter hinder vertical mixing and dilution of the pollutants. On the other hand, during much of the monsoon,

PM2.5 and PM10 concentrations in the ambient air in Dhaka remains well below the AQS for 24 hour averaging periods, although PM2.5 tends to exceed the AQS more frequently than PM10. It should be noted that the CAMS monitor at Sangshad Bhaban in Dhaka is located in a semi-residential area, and pollution hot spots within Dhaka can have significantly poorer air quality, which DoE observed at the second CAMS at Farmgate.

Table 2.6: Particulate concentrations at different sites in Bangladesh (Source: ADB 2006)

Name of sites Time of measurement Total suspended particle matter (μg/m3) Air Quality Standard (annual) 200 Bogra 2003-2004 170-531 Rajshahi 2004 329-680 Sirajganj 2003 400-420 Pabna 2004 500-829 Khulshi Oct 2002 – Mar 2003 213.1-317.8 Nasirabad Mar 2003 904 Agrabad Apr 2004 804 Chandgaon Sep 2002 – Feb 2003 172.6-208.4 Sunamganj (diff locations) Feb 2010 243.2-365

2.8 Review of earlier works The term “air quality” means the state of the air around us. Good air quality refers to clean, clear, unpolluted air. Clean air is essential to maintaining the delicate balance of life on this planet-not just for humans, but wildlife, vegetation, water and soil. Poor air quality is a result of a number of factors, including emissions from various sources, both natural and “human-caused”. Poor air quality occurs when pollutants reach high enough concentrations to endanger human health and/or the environment. Our everyday choices, such as driving cars and burning wood, can have a significant impact on air quality. Ambient air quality refers to the quality of outdoor air in our surrounding environment. It is typically measured near ground level, away from direct sources of pollution. Fine particulate matter with aerodynamic diameter less than 2.5 μm is a wide spread air pollution problem. In Dhaka, Bangladesh, the daily average of PM2.5 levels usually exceeds the Bangladesh national ambient air quality standard (NAAQS) of 65 μm /m3 in winter, although they meet the requirements during the monsoon season. As a result, in winter, the annual average never can comply with the national standard of 15 μm /m3. Lots of researches have been performed to monitor particulate matter at different polluted places in the home and aboard.

Barrett et al. 2007 [32] studied PM from power plants and found that, power plants release particulate matter, or soot tiny particles that are too small to see and that can be inhaled deep into the lungs, where they cause health problems e.g. suppress immune function, cause cancer and worsen cardiovascular disease and impair children’s lung development. Coal-fired power plants release more particulate matter pollution than do other fossil-fuel plants, and a large portion of that pollution is PM2.5. Approximately 21% to 44% of the particulate matter pollution released from coal-fired power plants is PM2.5.

According to Environmental Protection Agency [33], emissions of BC from U.S. sources total about 0.64 million tons (580 Gg) in 2005, which represents about 8% of the global total. Mobile sources account for a little more than half (52%) of the domestic BC emissions. Approximately 93% of the mobile source total is from diesel sources. Open biomass burning is the next largest source in the United States, accounting for about 35% of the total.

Reisinger et al. [34] studied to identify the sources for EC or BC in Vienna and found that, under summer conditions, diesel traffic is the major source for EC or BC and under winter conditions, space heating (also with biomass as fuel) is another important source.

Aerosol constituents (elemental carbon, organic carbon, soluble ions including organic acids, and selected trace metals) were investigated by Salam et al. [35] from samples of a field campaign that took place in the pre-monsoon season (May 2001) using low volume samplers at Bhola Island in the Bay of Bengal, Bangladesh. They found that carbonaceous material comprised the majority of the analyzed components and average concentrations of EC and OC were 2.8 and 4.6 µg/m3, respectively.

Fossati et al. [36] found that, ambient particulate matter (PM) has been associated with mortality and morbidity for cardiovascular disease.

Begum et al. [37] collected airborne particulate matter (PM) samples at a semi-residential area in Dhaka during the period of 1997-2005 by Gent sample. It was found that, due to the banning of leaded gasoline together with other stepwise policy intervention, the air quality of Dhaka city tends to become moderate but there was emission of Pb which was not so frequent. As a result the yearly average Pb value has increased slowly. It may

21 come from paints, manufacturing products for Pb acid batteries and foundries etc. Therefore, it was recommended that, suspect sources should be investigated and controlled for the management of Pb level in the ambient air.

Black carbon and other selected trace elements concentrations in aerosol samples collected at the Continuous Air Monitoring Station (CAMS) in Chittagong were investigated by Begum et al. [38] for possible source contributions. The particulate matter (PM) sampling was done from end of winter to middle of rainy season (February and July, 2007) using dichotomous sampler. The samples collected in two fractions of <2.5 μm (fine) and 2.5 to 10 μm (coarse) were analyzed for elemental concentrations by proton induced X-ray emission (PIXE), hydrogen by proton elastic scattering analysis (PESA), and black carbon by reflectance measurement. The sources were identified as biomass burning/brick kiln, soil dust, road dust, Zn source, Pb source, motor vehicle, CNG (compressed natural gas) vehicle and sea salt. It was found that in coarse fraction, the sea salt is mixed with Zn source and in fine fraction; the road dust factor is mixed with CNG vehicle source.

From the air particle (PM) collected from different locations of Dhaka city it was found that about 30-50 % of the PM10 mass (depending on location) is fine particles [39] with aerodynamic diameter less than 2.2 μm, which are mainly of anthropogenic origin and predominately from transport related sources. On the other hand, due to the meteorological reason and long-range transport during the wintertime, the PM concentrations remain much higher than the Bangladesh National Ambient Air Quality Standard (BNAAQS).

According to Baronet et al. [40], it was generally agreed that as much as 40 % of current net warming (10-20 % of gross warming) is attributable to black carbon. Because of its large effect on radiative forcing and relatively short residence time in the atmosphere, black carbon presents some unique opportunities for postponing the effects of climate change. Furthermore, since black carbon is considered responsible for about 30 % of the arctic melting, black carbon emission reductions can rapidly reduce the rate at which arctic ice is melting and avert associated consequences. Black carbon reduction policies can also result in large health benefits especially to citizens of developing countries. Black carbon can be controlled in developing countries through the implementation of cleaner fuels, new cooking technologies, and changing crop management practices.

Hopke et al. [41] studied to identify the sources of fine and coarse particulate matter in Dhaka, Bangladesh in 2010. It has been found that black carbon accounted for about 50 % of the total fine PM mass before the adoption of control policies. As a result, the PM emission as well as BC has not increased in proportion to the increase in the number of combustion sources like motor vehicles, diesel power generator or brick kiln. Positive Matrix Factorization (PMF) was applied to fine particle composition data from January 2007 to February 2009. It was found that motor vehicles contribute less BC with respect to brick kiln industry. BC is also transported over long distances, mixing with other particles along the way as demonstrated by a potential source contribution function analysis. Tran boundary transport of air pollution in the South Asian region has become an issue of increasing importance over the past several decades. The relative amounts of local and long-range transported pollutants are currently unknown.

The particulate matter sampling (both for PM10 and PM2.5) were done by Begum et al. [42] in winter (From February 17 to March 3, 2010) and in monsoon (July 5 to July 19, 2010) from the continuous air monitoring station (CAMS-2) at the Farm Gate site, Re- Constructed Mass (RCM) and Principal Component Analysis (PCA) methods were used for source identifications. From RCM method, identified sources were sulfate, sea salt, smoke, soil, carbonaceous sources, Zn and Pb depending on season. From PCA method, identified sources were mixed sources, soil dust, road dust, sea salt, Zn and fugitive Pb depending on the season. From winter data, it was found that at daytime, carbonaceous sources is highest (44 %) in PM2.5 whereas in PM10, soil dust is highest (39 %) among other sources and at nighttime, carbonaceous sources are highest both in PM2.5 and

PM10among other sources. From monsoon data, it was found that carbonaceous sources are 48 % and 57 % in PM2.5 at daytime and nighttime, respectively. On the other hand the percentage of soil dust in PM10is low at nighttime as well as daytime in monsoon season. The carbonaceous sources are diesel, gasoline and CNG fuels, coal and wood burning in the brick fields.

To understand impact of vehicle fleet characteristics on particulate matter (PM) concentration, sampling was conducted by Begum et al. [43] and it was observed that the PM concentrations were relatively higher during night compared to daytime, although the traffic density was lower at night. About 68 % of PM10 is PM2.5 during night whereas 58

% of PM2.5 accounts for PM10 during day, which mainly originates from a variety of

23 anthropogenic activities. Average BC concentration was found about 29 % of PM2.5 and sources are emissions from vehicles and/or from brick kilns. This result suggests that BC is primarily the result of the high traffic in this hot spot area and from other local sources such as brick kilns. It was also found that there are incidences of very high values of PM as well as BC concentration and these may have long-range contribution.

In a study, Begum et al. [44] found that due to the use of diesel in quick rental power plants, the air quality in Dhaka was decorated. More over during power cut, people use diesel generator for the power supply (specially in the commercial buildings, apartments, and private hospitals) which might be one of the reasons to get diesel signature in the carbon fraction analysis.

The potency of BC as a warming agent varies among source types and regions due to difference in co-emitted aerosols, transport and deposit in location. BC in indoor environment is largely due to cooking with bio-fuels. It was observed that, local people near the Gazipur sampling site sometime use biomass (wood, straw, cow dung etc.) for cooking. Approximately 20 % of black carbon is emitted from burning bio-fuels, 40 % from fossil fuels, and 40 % from open biomass burning [31].

So far we know from the literature review, there is no comprehensive work about carbonaceous particles in the air of Gazipur, Bangladesh. So this work is mainly focused on carbonaceous particles in the air of Gazipur.

CHAPTER-3 EXPERIMENTAL DETAILS

3.1 Air sampling Air sampling is defined as determining quantities and types of atmospheric contaminants by measuring and evaluating a representative sample of air. The most numerous environmental hazards and chemical, can be conveniently divided as-(a) the particulates and (b) the gasses or vapour. In filtration process, the air is passed through a filter medium normally a paper for solid contaminants and a sorbent for gasses. The volume of the air is measured against the amount of the contaminants captured. This gives concentration, which is expressed either as milligram per cubic centimeter (mg/cm3) or parts per million (ppm). There are two types of air sampling: (i) personal sampling and (ii) direct or real time sapling

Personal sampling: Personal sampling is used to both detect and measure exposures. It is done to determine the quality of the air the worker is breathing or would breathe if not protected. Samples are usually are collected by placing a battery operated air pump on the wearer belt and clipping a collection tube or filter in the breathing zone, usually on the cooler near the nose. Air from the environment is pulled into the collection device where the contaminants are trapped, and then sample are send to laboratory for analysis. Personal sampling is the most accurate measurement of worker’s actual exposure, because it goes where the worker goes and can be placed in the breathing zone (near the nose). In this case laboratory analysis of the sample may take 1-14 days.

Direct or real time sampling: Real time monitoring with direct-reading instruments provides an immediate measurement of the exposure in the air. It can be done with variety of equipment. The equipment selected for any permit space will normally depend upon the potential hazards present, including but not limited to gases, vapors, dust, flammable atmosphere, oxygen, radiation, heat and noise.

3.2 Description of the sampler The PM sampling was done by Air matrices mini vol. sampler developed jointly by the U.S. Environmental Protection Agency (EPA) and the Lane Regional Air

Pollution Authority. The sampling technique is a modification of the PM10 reference method described in the U. S. Code of Federal Regulations [45] and can be used for PM and gas sampling. The diagram of the sampling head for the unit is shown in Figure 3.1

Filter PM2.5 impaction plate PM10 impaction plate

To pump

Air Inlet Filter

Figure 3.1: Schematic diagram of the sampling head of Air matrices PM sampler

Basic operation of the sampler: The MiniVol. portable air sampler can be configured to collect either PM2.5, PM10, or TSP samples - but only one type at a time. The Mini Vol's pump draws air at 5 liters/minute through a particle size separator (impactor) and then through a 47mm filter. The 10 micron or 2.5 micron particle separation is achieved by impaction, or a TSP sample can be collected by removing the impactor(s). The particulate sample is caught on the filter, which must be weighed pre- and post-exposure with a microbalance accurate to one microgram. Sampling results are reported in micrograms/cubic meter. The Air matrices mini vol. sampler is basically a pump controlled by a programmable timer, which can be set to make up to six runs within 24 hours or throughout a week. The sampler is equipped to operate from either AC or DC power sources. The collection of correct particle size depends on volumetric flow rate. In case of mini vol. sampler the actual flow rate should be 5 liter per minute (lpm) at ambient conditions. To assure this flow rate through the size separator at different air temperatures and atmospheric pressures, the sampler were adjusted for each sampling site.

A PM sampler must have: 1) A sample air inlet system to provide particle size discrimination, 2) A flow control device capable of maintaining a flow rate within specified limits, means to measure the flow rate during the sampling period, and 3) A timing control device capable of starting and stopping the sampler.

The Air matrices mini vol. sampler meets all of these specifications and is equipped with: a) An inlet impactor capable of separating particulate matter to ≤10 µm. b) A specifications flow control device which maintains a specified flow rate. c) A flow meter to measure the flow rate during the sampling period. d) An elapsed time meter and e) A programmable timer that starts and stops the sampler unattended.

The Mini vol’s flow rate is generally less than the flow rates used by reference method devices. The lower rate results in a greater deviation in accuracy at low concentrations of particulate matter where precision can be lost through the handling and weighing of a minute particulate sample. However, at high particulate concentrations the sampler produces results that are precise and comparable to reference method samplers. While the Mini vol’s sampling method is not a reference or equivalent method, it has proven to be an excellent indicator of absolute ambient PM10 and PM2.5 concentrations [46]. Although the method used by portable PM10 and PM2.5 sampling does not wholly conform or comply with the reference method, the data collected by the sampler still serve as a useful supplement to data generated by PM10 and PM2.5 reference methods.

Particulate matter sampling mode In the particulate matter (PM) sampling mode, air is drawn through a particle size separator and then through a filter medium. Particle size separation is achieved by impaction. Critical to the collection of the correct particle size is the correct flow rate through the impactor. For the Mini vol. the actual volumetric flow rate must be 5 liters per minute at ambient conditions. To assure this flow rate through the size separator at differing air temperatures and atmospheric pressures, the sampler must be adjusted for each sampling project. Impactors are available with a 10-micron cut-point (PM10) and a 2.5- micron cut-point (PM25). Operating the sampler without an impactor allows for collection of total suspended particulate matter (TSP).

PM preseparator and filter holder assembly is shown in Figure 3.2.

The Mini Vol. Portable air Sampler has the following major components : Pump Module PM-2.5 Impactors PM-10 Impactors Multiple Impactor Adapters Louvered Inlets Filter Holder Assemblies Li-ion Battery Packs Battery Charger Universal Mounting Bracket All-Weather Transport Case

Figure 3.2: PM pre-separator and filter holder assembly

The inlet tube downstream from the filter takes the air to the twin cylinder diaphragm pump. From the pump, air is forced through a standard flow meter where it is exhausted to the atmosphere inside the sampler body. The programmable timer will automatically turn the pump off at the end of a sampling period.

3.3 Sampling sites Dhaka (Farmgate) site Sampling was done in two locations: (1) Farmgate of Dhaka city and (2) Joydebpur of Gazipur city, shown in Figure 3.4 and Figure 3.5, respectively. Farmgate is a hot spot site due to the proximity of several major roadways intersection and large number of vehicles plying through this area [47-48]. The site is commercial as well as semi industrial area. The Tejgaon industrial area is very near to this site. At Farmgate, the samplers were placed on the flat roof of the guardhouse of Bangladesh Agricultural Research Council (BARC). This location houses the second continuous air monitoring station (CAMS-2) in Dhaka. Figure 3.3 shows the different CAMS sites in Bangladesh and figure 3.4 shows the CAMS-2 (Farmgate, Dhaka) site map.

Figure 3.3: CAMS sites in Bangladesh

Figure 3.4: Map of sampling site, CAMS-2 (Farmgate, Dhaka)

Gazipur (Joydebpur) site Gazipur is a residential area of moderate population density. The sampling location is within 40 m from a local road and about 300 m from a secondary road with moderate traffic density. At Gazipur, the samplers were placed on the flat roof of the continuous air monitoring station (CAMS-4) site of Clean Air and Sustainable Environment (CASE) project, situated at Gazipur city corporation central symmetry, East Chandana, Joydebpur. The Joydebpur Chourasta, which is a very busy traffic point, is about 5 km west to this site. Joydebpur rail station (figure 3.5), through which daily 60 trains pass away, is about 100 m away from the sampling location. At “Konabari” and “Kodda” which are about 5 to 7 km to the north-west of the sampling site, more than 100 brick kilns are in production using kindle wood. There are many garments and other industries at 4 to 7 km distance from this site. Figure 3.6 shows the CAMS-4 (Joydebpur, Gazipur) site map.

Figure 3.5: Gazipur (Joydebpur) rail station and CAMS-4 site (red marked)

Figure 3.6: Map of sampling site ( CAMS-4, Joydebpur, Gazipur)

3.4 Sampling To measure the local impact and trans-boundary impact of particulate matter contribution of air pollutants, PM sampling was started from 02 December 2013 by two Air-Metrics Mini-Vol. samplers at Farmgate (Dhaka) and Joydebpur (Gazipur). The Samplers are placed on the roof of CAMS Buildings (figure 3.7) at 20 feet height from the ground level. There were two types of filters (teflon and quartz) for two different samples. The flow rate was maintained at 5 L/min and start and end time was recorded. After sample collection the used filters were preserved under 4°C temperatures. The Mini Vol. samplers were positioned with the intake upward and located in an unobstructed area PM10 and

PM2.5 were collected simultaneously for every 24 hours (from 10 a.m. to 10 a.m. of the next day) at each sampling site with two Mini Vol. samplers and the inlets of the samplers were kept 1m apart from each other. The pre-weighted conditioned clean filters were loaded to respective filter holder assembly at the conditioning room of CAMS. After sampling, filter holder assemblies (keeping the exposed filters inside) were brought to the conditioning room of the AEC, Dhaka, directly from the sampling site for conditioning and PM filter retrieval. Care was taken in transporting the exposed filter holder assemblies, so that there should be no PM loss.

Figure 3.7: Placing the Mini Vol. sampler at the Gazipur sampling site.

Preparation of PM sampler for sampling Following items were used to prepare PM sampler before recording data 1. Impactor grease: Apiezon M Grease 2. Solvent to mix with grease: Hexane 3. 47 mm filters: ring supported pure Teflon and Glass fiber having diameter 2.5 4. 47 mm Petri slides for storage and transport of the filters 5. Flow-meter Calibration: A Mini-Flo flow rate transfer standard device was used as the flow rate reference standards. 6. A calibrated digital manometer, Magnhilic gage was used to measure the drop across the Mini-Flo orifice element. 7. The actual ambient temperature and barometric pressure were also measured

47 mm filters: Two types of filters were used during the sampling- (i) Glass Fiber Filter and (ii) Teflon

Filter. Glass fiber filters have been used to collect PM10 and Teflon filters have been used to collect PM2.5. Figure 3.8 (a) and figure 3.8 (b), respectively show a teflon filter (a) before and (b) after exposure

(a) (b) Figure 3.8: Teflon filters, (a) before and (b) after exposure.

PM Masses were measured in the Chemistry Division of the Atomic Energy Centre

(AECD) Laboratory, Dhaka. The aerosol sample having both PM10 as well as PM2.5 were determined by weighing [49-50] filter before and after exposure using a micro balance (METTLER Model MT5) maintaining room temperature approximately at 22°C and relative humidity at 50 %. The difference in weights for each filter was calculated and the mass of each PM2.5 or PM10 sample can then be determined. The air filters were equilibrated at constant humidity and temperature of the balance room before every pre and post weighing. A Po-210 (alpha emitter) electrostatic charge eliminator (STATICMASTER) was used to eliminate the static charge accumulated on the filters before each weighing.

Calculation of the volume of air sampling Volume of air sample = sample flow rate × sample time Example: [50] Let, sample time = 8 hours = (8×60) min = 480 min Volume of air = 5 (liter/min) ×480 min Conversion of ppm (parts per million) to mg (milligrams) mg/cm3 = ppm× (molecular weight/24) If the molecular weight of the contaminrnt is not known it can be determined by using a periodic table.

Precautions During and after sampling, some precaution were taken such as- 1. The Mini-Vol. Air Matrices Sample were calibrated carefully. 2. The filters were equilibrated at about 50 % relative humidity and weighed on a micro balance prior to insert into filter holder. 3. After 24 hours collection period, the filter samples were retrieved equilibrated and reweighted. 4. Before chemical analysis, all the loaded filter papers were condition suitably.

3.5 Determination of black carbon

The concentration of BC in PM2.5 samples were determined by reflectance measurement in the laboratory of atomic energy center, Dhaka (AECD) using an EEL smoke stain Reflectometer M43D (Figure 3.9). This reflectometer works by the principle of Beer- Lambert law of attenuation.

Figure 3.9: Smoke Stain Reflectometer.

A schematic diagram of the reflectance measurement technique is shown in figure 3.10.

Figure 3.10: Schematic diagram of the reflectance measurement technique.

In the reflectometer method the light from a tungsten lamp passes through the orifice of an annular photocell to project on a well-defined spot on the sample. This light is transmitted two times through the orifice i.e. also reflecter back through it to the photocell. In such case the coefficient of absorption pf particles in the sample (bap) can be expressed as

2bap = ln [I0/I], where I0= incident light inyencity. and I = reflected light intencity.

The BC or shoot is responsible for around 30 % of the total light extinction and often more than 90 % of the light absorption by particulate matter [51]. It can therefore, BC be estimated from the measurement of bap by,

3 BC = [2 bap/ε] μg/m

Where ε is the coefficient of absorption efficiency in m2/g.

3.6 Meteorological conditions of the sampling sites In Bangladesh, the climate is characterized by high temperature and high humidity for most of the year, and distinctly marked seasonal variations in precipitation. Based on the meteorology, the year can be divided into four seasons, pre-monsoon (March-May), Monsoon (June-September), post-monsoon (October-November), and winter (December- February) [52]. The winter season is characterized by dry soil conditions, lower relative humidity, scanty rainfall and low northwesterly winds. The meteorological data used in this study was obtained from a meteorological station, Agargaon, Dhaka. During the dry winter and part of the post-monsoon season, the strength of north and north-westerly winds coming from India, Nepal, and southeastern China to the Bay of Bengal through Bangladesh can transport pollutants to the city. Moreover, during this season, wind speeds are low so that the locally emitted pollutants are not well dispersed into the downwind area. Mixing heights of the boundary layer are important factors influencing the dispersion of pollutants. The meteorological data for Dhaka (obtain from Agargaon Meteorological Station) during the sampling period is shown in Table 4.8 which is used for Gazipur also.

CHAPTER-4 RESULTS AND DISCUSSION

4.1 Particulate mass concentrations Air Particulate Matter sampling was performed by using Air Metrics Mini Vol. sampler for collecting PM2.5 in teflon filter paper and PM10 in Glass filter paper at Farmgate, Dhaka and Joydebpur, Gazipur from December 02, 2013 to February 27, 2014. The average air volume was 5 L/minute, and the sampling time was about 24 hours (10.00 am to next day 10.00 am). The samplers are placed on the roofs of CAMS-2 and CAMS-4 (Continuous Air Monitoring Station) buildings at 20 feet height at Farmgate, Dhaka and at central graveyard premises, Gazipur respectively. Particulate Matters (PM) were determined from both types of filter papers. The effects of meteorological parameters (e.g., Wind speed, wind direction, humidity, temperature, visibility and rain fall) on the air pollution was also studied in Dhaka.

4.1.1 PM2.5 mass concentration

The average 24 hours PM2.5 concentrations at Gazipur (Joydebpur) and Dhaka (Farmgate) during the months December 2013 to February 2014 are plotted in Figure 4.1 and summarized in Table 4.1.

PM2.5 mass concentration in Gazipur (Joydebpur)

In the month of December 2013, it was seen that the PM2.5 mass varied between minimum 110.28 µg/m3 (04/12/2013) and maximum 185.51 µg/m3 (20/12/2013) 3 and the average PM2.5 mass concentration was 146.71 µg/m .

In the month of January 2014, it was seen that the PM2.5 mass varied between minimum 80.93 µg/m3 (09/1/2014) and maximum 208.66 µg/m3 (17/01/2014) and 3 the average PM2.5 mass concentration was 129.78 µg/m .

In the month of February 2014, it was seen that the PM2.5 mass varied between minimum 89.35 µg/m3 (26/2/2014) and maximum 157.55 µg/m3 (18/02/2014) and 3 the average PM2.5 mass concentration was 119.94µg/m .

It is summarized from Table 4.1 that at Gazipur the average concentration of PM2.5 for the sampling period (December 2013 and February 2014) was 132.65 µg/m3.

PM2.5 mass concentration in Dhaka (Farmgate)

In the month of December 2013, it was seen that the PM2.5 mass varied between minimum 40.42 µg/m3 (26/12/2013) and maximum 243.55 µg/m3 (20/12/2013) 3 and the average PM2.5 mass concentration was 123.74 µg/m .

In the month of January 2014, it was seen that the PM2.5 mass varied between minimum 70.32 µg/m3 (17/01/2014) and maximum 246.53 µg/m3 (03/01/2014) and 3 the average PM2.5 mass concentration was 121.96 µg/m .

In the month of February 2014, it was seen that the PM2.5 mass varied between minimum 40.28 µg/m3 (16/02/2014) and maximum 150.66 µg/m3 (06/02/2014) and 3 the average PM2.5 mass concentration was 94.17 µg/m .

Therefore it is summarized from Table 4.1 that the average concentration of PM2.5 for the sampling period (December 2013 to February 2014) at Farmgate (Dhaka) was 114 µg/m3.

Figure 4.1: Concentrations of PM2.5 in the air of Dhaka and Gazipur (During December 2013 - February 2014)

Table 4.1: Concentrations of PM2.5 in Gazipur (Joydebpur) and Dhaka (Farmgate)

3 Concentrations of PM2.5 (µg/m ) in Gazipur (Joydebpur) and Dhaka (Farmgate) Date Gazipur Dhaka Date Gazipur Dhaka Date Gazipur Dhaka 02/12/13 157.50 102.84 01/01/14 88.43 109.07 02/02/14 132.04 112.03 04/12/13 110.28 72.45 03/01/14 125.37 246.53 04/02/14 150.88 130.42 06/12/13 147.92 83.63 05/01/14 133.70 207.22 06/02/14 121.23 150.66 08/12/13 145.37 77.88 07/01/14 183.29 143.24 08/02/14 95.79 93.48 10/12/13 132.64 106.44 09/01/14 80.93 210.97 10/02/14 98.94 80.42 12/12/13 151.57 184.31 11/01/14 81.02 71.20 12/02/14 95.42 87.45 14/12/13 140.56 188.09 13/01/14 135.88 113.64 14/02/14 106.11 58.52 16/12/13 127.31 115.40 15/01/14 129.35 93.33 16/02/14 133.47 40.28 18/12/13 133.10 133.33 17/01/14 208.66 70.32 18/02/14 157.55 56.80 20/12/13 185.51 243.55 19/01/14 97.63 86.01 20/02/14 114.49 132.79 22/12/13 169.35 125.60 21/01/14 130.14 166.39 22/02/14 129.21 90.24 24/12/13 134.86 129.26 23/01/14 184.21 72.82 24/02/14 134.77 84.36 26/12/13 162.50 40.42 25/01/14 120.88 76.40 26/02/14 89.35 106.71 28/12/13 174.86 121.94 27/01/14 125.65 81.60 30/12/13 127.36 131.00 29/01/14 147.64 80.59 31/01/14 103.70 98.03 Min 110.28 40.42 Min 80.93 70.32 Min 89.35 40.28 Max 185.51 243.55 Max 208.66 246.53 Max 157.55 150.66 Mean 146.71 123.74 Mean 131.52 121.96 Mean 119.94 94.17 Median 145.37 121.94 Median 129.35 93.33 Median 121.23 90.24

4.1.2 PM10 mass concentration

The average 24 hours PM10 concentrations at Gazipur (Joydebpur) and Dhaka (Farmgate) during the months December 2013 to February 2014 are plotted in Figure 4.2 and the recorded data are summarized in Table 4.2.

PM10 mass concentration at Gazipur (Joydebpur)

In the month of December 2013, it was seen that the PM10 mass varied between minimum 177.58 µg/m3 (24/12/2013) and maximum 196.18µg/m3 (06/12/2013) 3 and the average PM10 mass concentration was 189.48 µg/m .

In the month of January 2014, it was seen that the PM10 mass varied between minimum 178.85 µg/m3 (31/01/2014) and maximum 225.5 µg/m3 (19/01/2014) 3 and the average PM2.5 mass concentration was 200.43 µg/m .

In the month of February 2014, it was seen that the PM10 mass varied between minimum 156.53 µg/m3 (10/2/2014) and maximum 173.34 µg/m3 (02/02/2014) and 3 the average PM10 mass concentration was 163.57 µg/m .

Therefore it is summarized from Table 4.2 that the average concentration of PM10 for the sampling period (December 2013 - February 2014) in Gazipur was 185.80 3 µg/m .

PM10 mass concentrations in Dhaka (Farmgate)

In December, 2013 the average 24 hours concentration of PM10 mass varied between minimum 201.53 μg/m3 (28/12/2013) and maximum 416.59 μg/m3 (22/12/2013) with an average of 285.93 μg/m3.

In January, 2014 these values varied minimum between 87.27 μg/m3 (17/01/2014) and maximum 363.47 μg/m3 (05/01/2014) with an average of 202.59 μg/m3.

3 In February, 2014 PM10 mass varied between minimum 89.4 μg/m (16/02/2014) and maximum 266.26 μg/m3 (20/02/2014) with an average of 188.35 μg/m3.

Therefore it is summarized from Table 4.2 that the average concentration of PM10 for the sampling period in Dhaka (Farmgate) was 185.80 µg/m3.

Figure 4.2: Concentrations of PM10 in the air of Dhaka and Gazipur (During December 2013-February 2014)

Table 4.2: Concentrations of PM10 at Gazipur (Joydebpur) and Dhaka (Farmgate)

3 Concentrations of PM10 (µg/m ) at Gazipur (Joydebpur) and Dhaka (Farmgate) Date Gazipur Dhaka Date Gazipur Dhaka Date Gazipur Dhaka

02/12/13 190.46 208.56 01/01/14 198.69 246.30 02/02/14 173.34 145.21 04/12/13 193.40 235.40 03/01/14 197.29 271.02 04/02/14 166.72 194.17 06/12/13 196.18 309.54 05/01/14 194.30 363.47 06/02/14 166.32 258.49 08/12/13 196.13 217.08 07/01/14 195.59 241.48 08/02/14 160.70 170.57 10/12/13 194.39 208.77 09/01/14 198.88 324.49 10/02/14 156.53 170.22 12/12/13 195.22 392.00 11/01/14 194.10 179.49 12/02/14 162.35 264.77 14/12/13 190.56 286.74 13/01/14 197.02 161.09 14/02/14 164.24 248.29 16/12/13 189.31 245.11 15/01/14 202.38 112.69 16/02/14 163.10 89.40 18/12/13 188.67 257.65 17/01/14 219.74 87.27 18/02/14 160.20 121.60 20/12/13 188.15 359.98 19/01/14 225.50 205.20 20/02/14 158.73 266.26 22/12/13 181.03 416.59 21/01/14 219.50 192.34 22/02/14 160.30 115.31 24/12/13 177.58 401.27 23/01/14 208.52 156.94 24/02/14 165.20 182.40 26/12/13 180.23 340.65 25/01/14 200.69 161.00 26/02/14 168.72 221.81 28/12/13 188.20 201.53 27/01/14 190.82 158.30 30/12/13 192.74 208.00 29/01/14 184.94 180.80 31/01/14 178.85 199.58 Min 177.58 201.53 Min 178.85 87.27 Min 156.53 89.40 Max 196.18 416.59 Max 225.50 363.47 Max 173.34 266.26 Mean 189.48 285.93 Mean 200.43 202.59 Mean 163.57 188.35 Median 190.46 257.65 Median 198.69 180.80 Median 163.10 182.40

4.1.3 Ratio of the concentrations of PM2.5 and PM10

PM2.5/PM10 has been calculated for both the sampling sites Gazipur (Joydebpur) and Dhaka (Farmgate) and plotted against sampling dates (Figure 4.3 and Figure 4.4). Also data are summarized in Table 4.3.

PM2.5/PM10 concentrations ratio at Gazipur (Joydebpur)

In December, 2013 PM2.5/PM10 varied between minimum value 0.57 (04/12/2013) and maximum 0.99 (20/12/2013) with an average of 0.78.

In January, 2 014 PM2.5/PM10 varied between minimum value 0.41 (09/01/2014) and maximum 0.95 (17/01/2014) with an average of 0.65.

In February, 2014 PM2.5/PM10 varied between minimum value 0.53 (26/02/2014) and maximum 0.98 (18/02/2014) with an average of 0.73 and the average concentration of

PM2.5/PM10 for the sampling period (December 2013 to February 2014) at Gazipur was 0.72.

Therefore it is summarized from Table 4.3 that at Gazipur in December 2013,

January 2014 and February 2014 the average PM2.5 mass were about 78 %, 65 % and

73 %, respectively of the PM10 mass. It is observed from the collected data that, during the sampling period PM2.5/PM10 ratios randomly varied and no significant variation was seen. Mean value along with maxima and minima for the ratios were also calculated and summarized in Table 4.3. The mean PM10/PM2.5 ratio was around 0.72, which suggest that on an average 72 % of the PM10 was PM2.5. The maximum ratio was 0.99 which indicates that in that case most of the PM10 are PM2.5. These could be due to wash out of coarse particles (PM10-PM2.5) by meteorological conditions (Table 4.8, appendix-3).

PM2.5/PM10 concentrations ratio in Dhaka (Farmgate)

In December, 2013 PM2.5/PM10 varied between minimum value 0.12 (26/12/2013) and maximum 0.68 (20/12/2013) with an average of 0.45.

In January, 2014 PM2.5/PM10 varied between minimum value 0.40 (11/01/2014) and maximum 0.91 (3/01/2014) with an average of 0.60.

In February, 2014 PM2.5/PM10 varied between minimum value 0.24 (14/02/2014) and maximum 0.78 (22/02/2014) with an average of 0.50 and the average concentration of

PM2.5/PM10 for the sampling period (December 2013 to February 2014) at Gazipur was 0.52.

The PM2.5/PM10 data show that in the air of Dhaka in December 2013, January 2014 and February 2014, the average PM2.5 mass were about 43 %, 61 % and 50 %, respectively of the PM10 mass. Mean value along with maxima and minima for the ratios were also calculated and summarized in Table 4.3. During the sampling period, the mean PM10/PM2.5 ratio was around 0.52, which suggest that on an average

52% of the PM10 was PM2.5. This indicates that for the majority of days about 50% of the PM mass concentrations are fine particles with aerodynamic diameter less than 2.5 µm, which are mainly of anthropogenic and urban activities. In

Dhaka, there are significant emissions from automobiles and other anthropogenic activities related to the extremely high population density. Biomass/coal burning for cooking and in the brick kilns around the city contributes significantly to these emissions [53-54].

Figure 4.3: Ratio of the concentrations of PM2.5 and PM10 in the air of Gazipur

Figure 4.4: Ratio of the concentrations of PM2.5 and PM10 in the air of Dhaka (During December 2013 - February 2014)

Table 4.3: Ratio of the concentrations of PM2.5 and PM10 in the air of Gazipur and Dhaka

PM2.5/PM10 Date Gazipur Dhaka Date Gazipur Dhaka Date Gazipur Dhaka 2/12/13 0.83 0.49 1/1/14 0.45 0.44 2/2/14 0.76 0.77 4/12/13 0.57 0.31 3/1/14 0.64 0.91 4/2/14 0.9 0.67 6/12/13 0.75 0.27 5/1/14 0.69 0.57 6/2/14 0.73 0.35 8/12/13 0.74 0.36 7/1/14 0.94 0.59 8/2/14 0.6 0.55 10/12/13 0.68 0.51 9/1/14 0.41 0.65 10/2/14 0.63 0.47 12/12/13 0.78 0.47 11/1/14 0.42 0.4 12/2/14 0.59 0.33 14/12/13 0.74 0.66 13/01/14 0.69 0.71 14/02/14 0.65 0.24 16/12/13 0.67 0.47 15/01/14 0.64 0.83 16/02/14 0.82 0.45 18/12/13 0.71 0.52 17/01/14 0.95 0.81 18/02/14 0.98 0.47 20/12/13 0.99 0.68 19/01/14 0.43 0.42 20/02/14 0.72 0.5 22/12/13 0.94 0.3 21/01/14 0.59 0.87 22/02/14 0.81 0.78 24/12/13 0.76 0.32 23/01/14 0.88 0.46 24/02/14 0.82 0.46 26/12/13 0.9 0.12 25/01/14 0.6 0.47 26/02/14 0.53 0.48 28/12/13 0.93 0.61 27/01/14 0.66 0.52 30/12/13 0.66 0.63 29/01/14 0.8 0.45 31/01/14 0.58 0.49 Min 0.57 0.12 0.41 0.40 0.53 0.24 Max 0.99 0.68 0.95 0.91 0.98 0.78 Mean 0.78 0.45 0.65 0.60 0.73 0.50 STD 0.12 0.16 0.18 0.17 0.13 0.16 Median 0.75 0.47 0.64 0.55 0.73 0.47

Trends in particulate matter

The above stated result suggests that in Dhaka the PM2.5 mass concentration has

decreasing trend but PM10 has increased. The reduction in PM2.5 fraction of the

particulate pollution seems to be compensated by increasing the course (PM10) fraction. Major portion of these course particles are mainly originated from soil, road dust and construction activities. About 60 % to 70 % of coarse mass is soil dust including road dust in the Dhaka city.

4.1.4 Sources of pollutants The calculated ratio of PM gives an idea about the origin of the particulate pollutants.

In general, major sources of PM2.5 fraction is anthropogenic. Higher ratio tells anthropogenic component is dominated source of pollution. During the sampling period the average ratio of PM (PM2.5/PM10) at Gazipur and Dhaka were 0.72 and 0.52 respectively. This is because in Dhaka majority of the vehicles ply on the roads use CNG whereas at Gazipur heavy duty trucks and inter district buses ply on roads.

These trucks use diesel and emit mostly BC, OC, and SO2. The contribution of PM2.5 may also come from the brick kilns as all the brick kilns are in operation during winter. Coal fired brick kilns emit huge amount of gaseous pollutants into the air. It was observed that, due to conversion of vehicles to CNG, the contributions of motor vehicles in fine PM fraction have decreased but the contribution from brick kilns increased.

The high value of the ratio of PM (PM2.5/PM10) indicates the trans-boundary effect

[55]. Since PM2.5 fractions have relatively high residence time, and this fraction could have regional contribution apart from local sources. It was observed from the wind direction pattern that during the winter time, the wind comes mainly from north and northwest directions. There are some source’s locations in these areas like Afghanistan, Bay of Bengal, Arabian Sea and Oman potentially can contribute to local PM (especially PM2.5) levels through long range transport, because of its relatively longer suspension time. Effect of coal based power plant located in Indian border which is in the north-west part of Bangladesh on the augment of BC is also noticeable. The reasons for the high peaks in PM2.5 concentration during winter are not only caused by seasonal fluctuatio of the emissions, but also by meteorological effects. Average source contributions derived from the PMF modeling for a semi residential site [56] is shown in Table 4.4

Table 4.4: Source contributions: 2005-2006, for a semi-residential site (Dhaka)

Fine sample Coarse sample Source Concentration Concentration % % (µg/m3) (µg/m3)

Soil dust 14.8 2.934 43.8 15.055

Zn source 3.53 0.701 5.2 1.786

Brick kilns 18.7 3.709 ------

Road dust 3.56 0.707 2.21 0.758

Metal smelter 0.67 0.133 4.97 1.704

Sea salt 4.34 0.862 5.26 1.807

Motor vehicles 54.4 1.0797 38.6 13.259

Concentrations of PM found in the present study sites and National Ambient Air Quality Standard (NAAQS) emission for different countries together with WHO guideline are presented in Table 4.5. It is concluded from the data that the concentrations of both PM10 and PM2.5 for both of the sampling sites are higher than the NAAQS for Bangladesh and other countries of the world.

Table 4.5: Concentrations of PM found in the present study and current Natinal Emission Standards.

Present Study National Ambient Air Quality Standard

sites (NAAQS)

Average Concentrations Gazipur BD IND PAK Thai US WHO Time Dhaka of the Pollutants Std Std Std Std Std Guideline (hours)

PM10 24 185 227 150 100 150 120 150 50 (μg/m3)

PM2.5 24 132 114 65 60 35 50 35 20 (μg/m3)

(Source: CASE project, DoE)

4.1.5 Comparisons of PM mass concentrations between present data and previous data for Farmgate, Dhaka. Comparisons between the concentrations of PM mass data collected from present study (December 2013-February, 2014) and previous years data in winter (dry season) and rainy season at Farmgate, Dhaka are shown in Table 4.6 and plotted in Figure 4.5 and

Figure 4.6. The last 10 years data (source: CASE, DoE) for concentration of PM2.5

and PM10 in the air of Dhaka were compared with the present investigations. We have found that our findings are in agreement with CASE data. Therefore, our study reveals that, though the government has taken several steps to minimize air pollution

but the concentration of PM2.5 and PM10 remains almost same in Dhaka and can never comply the Bangladesh National Ambient Air Quality Standard (BNAAQS) for annual average. However, it is observed from these data that, though during the dry season (winter) the concentrations of PM was quite high, during the rainy season the concentrations meet the BNAAQS for daily average.

Table 4.6: Average monthly PM data (μg/m3) in the air of Dhaka during winter and rainy season. Winter season Rainy season

3 3 3 3 Month PM10(μg/m ) PM2.5(μg/m ) Month PM10(μg/m ) PM2.5(μg/m ) December'02 252 192 June'02 56 23 January'03 271 196 July'02 88 32 February'03 244 151 August'02 66 28 December'03 168 108 June'03 68 27 January'04 192 130 July'03 46 19 February'04 236 119 August'03 50 23 December'04 248 136 June'04 69 29 January'05 250 166 July'04 55 19 February'05 205 115 August'04 54 23 December'05 240 188 June'05 70 27 January'06 260 185 July'05 47 22 February'06 235 158 August'05 51 27 December'06 175 113 June'06 60 28 January'07 199 125 July'06 40 23 February'07 230 127 August'06 42 25 December'07 242 131 June'07 62 23 January'08 242 162 July'07 42 21 February'08 196 111 August'07 46 25 December'08 179 115 June'08 66 25 January'09 207 127 July'08 44 18 February'09 247 133 August'08 42 23 December'09 163 103 June '09 72 29 January'10 246 117 July '09 50 22 August February'10 152 81 '09 56 29 December'10 210 116 June '10 74 31 January'11 277 137 July '10 101 52 August February'11 182 61 '10 78 33 December'11 188 101 January'12 147 104 February'12 179 98 December'12 252 174 January'13 262 193 February'13 217 176 December'13 285 123 January'14 202 121 February'14 188 94 Source: Clean Air and Sustainable Environment (CASE) Project, DoE.

Figure 4.5 and Figure 4.6 show comparisons between the concentrations of PM mass data collected from present study (December 2013-February, 2014) and previous years data in winter (dry season) and rainy season at Farmgate,

Figure 4.5: Average monthly PM data (μg/m3) in the air of Dhaka during winter

Figure 4.6: Average monthly PM data (μg/m3) in the air of Dhaka during rainy season.

4.2 Concentrations of black carbon (BC)

The concentration of black carbon in PM2.5 samples were determined by reflectance measurement in AECD laboratory using an Evans Electro selenium Limited (EEL) type Smoke Stain Reflectometer [57]. Secondary standards of known black carbon concentrations were used to calibrate the reflectometer. The concentrations are defined based on the amount of reflected light that is absorbed by the filter sample and an assumed mass absorption coefficient. It is related to the concentration of light absorbing carbon through standards of carbon with known areal density.

The 24 hours average values of BC in PM2.5 during the sampling period (December 02, 2013 to February 28, 2014) are shown in Table 4.7 and plotted in Figure 4.7. The trend of varying the concentrations of BC over date could be explained by using meteorological data which is shown in table 3.1 and appendix-3.

Concentrations of BC at Gazipur (Joydebpur) In the month of December 2013, it was found that, the average 24 hours 3 concentration of BC in PM2.5 varied between minimum 41.64 μg/m (2/12/2013) and maximum 116.30 μg/m3 (14/12/2013) with an average 80.13 μg/m3.

In January 2014, it was found that, the average 24 hours concentration of BC in 3 PM2.5 varied between minimum 42.55 μg/m (15/01/2014) and maximum 90.19 μg/m3 (23/01/2014) with an average 66.59 μg/m3.

In February 2014, it was observed that, the average 24 hours concentration of 3 BC in PM2.5 varied between minimum 53.45 μg/m (02/2/2014) and maximum 108.13 μg/m3 (18/2/2014) with an average 74.08 μg/m3. The average concentration of BC for the sampling period (December 02, 2013 to February 28, 2014) was 73.72 μg/m3.

Concentrations of BC at Farmgate, Dhaka In the month of December 2013, it was found that, the average 24 hours 3 concentration of BC in PM2.5 varied between minimum 12.25 μg/m (26/12/2013) and maximum 40.67 μg/m3 (8/12/2013) with an average 31.11 μg/m3.

In January 2014, it was found that, the average 24 hours concentration of BC in 3 3 PM2.5 varied between 18.13μg/m (15/1/2014) and 35.94μg/m (9/1/2014) with an average 24.92 μg/m3.

In February 2014, it was observed that, the average 24 hours concentration of 3 3 BC in PM2.5 varied between 11.17μg/m (16/2/2014) and 44.47μg/m (6/2/2014) with an average 25.84 μg/m3.

The average concentration of BC for the sampling period (December 02, 2013 to February 28, 2014) was 27.2μg/m3.

Figure 5.1 shows the comparative study of black carbon in the air of Dhaka and Gazipur. It was found that the concentration of black carbon in the air of Gazipur is quite high (almost three times) than that of Dhaka.

Figure 4.7: Concentrations of black carbon in the air of Dhaka and Gazipur (During December 2013-February 2014).

Table 4.7: Concentration of BC (μg/m3) in the air of Dhaka and Gazipur

Gazipur Dhaka Gazipur Dhaka Gazipur Dhaka Date BC BC Date BC BC Date BC BC (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) 02/12/13 41.64 29.68 01/01/14 85.42 26.02 02/02/14 53.45 20.96 04/12/13 85.42 35.37 03/01/14 64.71 20.17 04/02/14 56.80 21.45 06/12/13 96.51 29.19 05/01/14 74.37 32.18 06/02/14 99.85 44.47 08/12/13 89.04 40.67 07/01/14 75.69 24.45 08/02/14 60.10 17.25 10/12/13 87.92 29.80 09/01/14 63.31 35.94 10/02/14 72.58 28.64 12/12/13 92.60 35.62 11/01/14 65.75 25.41 12/02/14 66.38 27.58 14/12/13 116.30 36.83 13/01/14 47.89 20.38 14/02/14 61.58 23.15 16/12/13 89.80 31.06 15/01/14 42.55 18.13 16/02/14 67.46 11.17 18/12/13 72.34 38.50 17/01/14 73.34 22.82 18/02/14 108.13 19.20 20/12/13 66.38 34.91 19/01/14 78.19 22.31 20/02/14 89.80 39.27 22/12/13 71.84 30.27 21/01/14 54.85 32.45 22/02/14 75.16 25.32 24/12/13 78.19 26.34 23/01/14 90.19 20.34 24/02/14 97.44 30.87 26/12/13 69.70 12.25 25/01/14 55.49 21.50 26/02/14 54.31 26.60 28/12/13 75.42 29.20 27/01/14 44.09 23.20 30/12/13 68.79 27.00 29/01/14 83.08 28.42 31/01/14 50.64 21.51 Min 41.64 12.25 42.55 18.13 53.45 11.17 Max 116.30 40.67 90.19 35.94 108.13 44.47 Mean 80.13 31.11 66.59 24.92 74.08 25.84 STD 17.02 6.75 15.16 5.22 18.69 8.89 Median 78.19 30.27 65.75 23.20 67.46 25.32

4.2.1 Fraction of black carbon in PM2.5

Fraction of black carbon in PM2.5 is shown in Figure 4.8 which indicates the comparative state of black carbon in PM2.5 in the air of Dhaka and Gazipur during the sampling period. It was found that the average fractions of black carbon in PM2.5 in the air of Dhaka and Gazipur were 26 % and 54 %, respectively.

Figure 4.8: Fraction of BC in PM2.5 in the air of Gazipur and Dhaka (During Dec. 2013-Feb. 2014)

4.3 Variation of PM and BC with respect to meteorological condition The local meteorology has a substantial effect on the concentration of particulate matter and black carbon in Dhaka and Gazipur. During dry winter and part of the post monsoon season, the strength of north, north westerly wind from the Himalayas to the Bay of Bengal is so low that the wind can not transport the particulate matter from the sources of the city to a long distance. The mixing height in the boundary layer is one of the important factors to assess the influence of meteorology on the dispersion of pollutants. There are very small amounts of rainfall during winter due to north, north-westerly dry air coming over the land surface. As a result the whole meteorological situation in the winter acts in favor to the severe particulate pollution over the city. In the monsoon and pre-monsoon seasons, the intense sunlight, high wind speed from the Bay of Bengal with a lot of water vapor, enormous amount of rain fall, well disperse pollutants within higher mixing height are all lead to a lower concentration of particulate matter in the ambient air.

4.3.1 Effect of wind directions Wind direction shows the path way of wind which blows in different places with time. Domination of prevailing wind direction varies from season to season for Dhaka and Gazipur city. During monsoon and pre-monsoon seasons most of the winds come from south and south-east direction whereas during post-monsoon and winter season the north-east, north and north-west are the dominating wind directions. PM masses were relatively higher when the winds came from south-west to north-west directions. Possible explanation is that, usually Dhaka receives winds from south-west and north-west direction during winter and post-monsoon season with low wind speed and low temperature. Most of the brick kilns with low stack heights are located in the south west to North West belt of Dhaka and Gazipur city. These brick kilns are one of the main sources of particulate matter and the particles emitted from these low stack heights generally settles over the city under stagnant conditions. Moreover, when wind comes from south-west to north-west direction, it comes over land which could be associated with the higher mass of particulate matter.

4.3.2 Effect of wind speed Wind speed has an important control on the concentration of particulate matter. Strong winds decrease the particulate matter concentration and low winds allow the high level of particulate matter. PM2.5 concentrations measured in Paris were also inversely proportional to wind speed values [58]. With the increasing wind speed, the dispersion mechanism decreases the particle concentration. Variation of PM with respect to wind speed is plotted in Figure 4.9 to Figure 4.12 for Dhaka and Gazipur city which comply with the earlier result in such cases.

Figure 4.9: Variation of PM2.5 with respect to wind speed in Gazipur.

Figure 4.10: Variation of PM2.5 with respect to wind speed in Dhaka.

Figure 4.11: Variation of PM10 with respect to wind speed in Gazipur.

Figure 4.12: Variation of PM10 with respect to wind speed in Dhaka.

It was found that the variation of PM10 with respect to wind speed was more significant in Dhaka than Gazipur. The above graphs indicate that, the concentration of PM in the air of Dhaka (Farmgate) decrease more rapidly with increasing wind speed than that of Gazipur.

Variation of BC with respect to wind speed is plotted in Figure 4.13 and Figure 4.14 which indicate that at Gazipur the concentration of BC decreases with higher wind speed where as in Dhaka the concentration of BC increases with higher wind speed. This may happen because in Bangladesh air is generally blows from the north and north-west in winter. Hence, as the ultrafine particles (BC) can reside the environment for long time and can travel long distance, in winter the particulate matter emitted from the sources (brick kilns and industries) situated at Aminbazar, Savar and Tongi which are at the north and north-west of Dhaka increases the concentration of BC in the air of Dhaka.

Figure 4.13: Variation of black carbon with respect to wind speed in the air of Gazipur (During December 2013-February 2014)

Figure 4.14: Variation of black carbon with respect to wind speed in the air of Dhaka (During December 2013-February 2014)

4.3.3 Effect of humidity Relative humidity is a major constituent of the atmosphere where the pollutants are emitted and dispersed. In general particle fractions are negatively correlated with relative humidity. Relation between mass of particulate matter and relative humidity depends on the composition of particulate matter. The negative correlation implies that the particulate matter in Dhaka contains hygroscopic components which attract water from air. Many compounds like sodium chloride, ammonium sulfate, ammonium nitrate, sea salt attract water vapor and are dissolved in the attracted water. Due to this water uptake the particulate matter become so large that sampling does not collect them. Figure 4.15 to Figure 4.20 show the variation of black carbon and PM with respect to humidity at Gazipur and Dhaka respectively during December 2013 to February 2014. These figures indicate that the concentration of black carbon (BC) increases with lower humidity.

Figure 4.15: Variation of black carbon with respect to humidity in the air of Gazipur (During December 2013-February 2014)

Figure 4.16: Variation of black carbon with respect to humidity in the air of Dhaka (During December 2013-February 2014)

Figure 4.17: Variation of PM2.5 with respect to humidity in the air of Gazipur (During December 2013-February 2014)

Figure 4.18: Variation of PM10 with respect to humidity in the air of Gazipur (During Dec. 2013-Feb. 2014

Figure 4.19: Variation of PM2.5 with respect to humidity in the air of Dhaka (During Dec. 2013-Feb. 2014)

Figure 4.20: Variation of PM10 with respect to humidity in the air of Dhaka (During December 2013-February 2014)

4.3.4 Effect of rain fall Rain fall is an important factor for particulate matter. The rain fall increases the mass of particulate matter hence they are washed out from the environment. Due to rainfall the amount of particulate matter in monsoon is less with respect to other seasons. During the present study there was no significant rainfall.

4.3.5 Effect of temperature Atmospheric stability has a great affect on the concentration of air pollutants in an area. Stability depends on the vertical temperature gradient. Unfortunately the effect of the stability of the atmospheric boundary layer was not characterized because data of the vertical temperature gradient were not available. From the earlier studies it is known that, there was a seasonal variation in the average difference in daily maximum and minimum temperature. In the pre-monsoon and monsoon season less temperature difference with high wind speed leads to well mixed mixing layers which allow the well dispersion of particulate matter. On the other hand, in the winter season the higher difference between daily maximum and minimum temperature with low wind speed hold the particulate matter within the stagnant stable surface layer specially early in the morning and late afternoon. Temperature is also an important variable for the volatilization of particulate matters. Chemical specification analysis of Dhaka’s particulate matter showed that, a high amount of secondary aerosols are present in the form of ammonium nitrate, ammonium sulfate, ammonium bisulfate etc. as a result of the conversion of gaseous emission of different precursor gases. The meteorological data during the sampling period is shown in Table 4.8.

Table 4.8 Meteorological data during the sampling period (obtained from Agargaon Meteorological Station, Dhaka). Wind direction Humidity Temperature Visibility Rain fall WS Date N-north, E-east, (%) (oC) (km) (mm) (m/s) W-west, S-south 02/12/13 65.875 21.8 3.4 0 0.75 NW 04/12/13 69.25 22.2 4.4 0 0.5 WN 06/12/13 70.375 20.2 4 0 0 NW 08/12/13 68.75 19.7 3.6 0 0.25 N 10/12/13 71.875 19.8 1.7 0 1 NE 12/12/13 67.125 19.1 0.8 0 0 N,E 14/12/13 70.625 21 2.6 0 0.5 N 16/12/13 68.75 21.2 3.2 0 0.5 N 18/12/13 69.5 17.9 1.8 0 0.25 N 20/12/13 80.125 17 1.4 0 0.5 WNW,W 22/12/13 80.625 14.6 1.8 0 0 WN,N,W, 24/12/13 68.125 15.6 2.9 0 1.625 WN,W,WN,WS 26/12/13 73.625 14.8 2.1 0 1.125 NE 28/12/13 84.25 14 1.6 0 0 N,WN 30/12/13 72.5 16 2.3 0 0.25 WN 01/01/14 63.625 18.4 2 0 0.75 E 03/01/14 66 20 1.8 0 1.25 WN 05/01/14 76.875 20 1.8 0 1 WN 07/01/14 77.5 21.3 2.5 0 0.5 NE.WN 09/01/14 87 12.5 2.9 0 0.75 WN,W,WN 11/01/14 63.125 12.3 1.3 0 0.5 WN 13/01/14 67.875 15.8 2.7 0 1.625 N,WN 15/01/14 88.5 17.6 2.5 0 0.75 N 17/01/14 84.5 18.5 2.5 0 1.125 N 19/01/14 72 20 3.1 0 1.25 WN 21/01/14 85.125 21.5 3 0 2.25 N,WN,W,WN 23/01/14 66.125 19.4 3.6 0 0.5 WN,W,WN 25/01/14 61.125 18.5 3 0 1.375 W,N,WN,W 27/01/14 70 20.2 2.9 0 2.625 W,WN,W 29/01/14 67.375 19.4 2.9 0 0.75 WN,W 31/01/14 81 18.5 2.9 0 1.5 N 02/02/14 66.25 16 2.5 0 2 N 04/02/14 77.125 16.3 3.2 0 1.25 W

Wind direction Humidity Visibility Rain fall WS Date Temp.(oC) N-north, E-east, (%) (km) (mm) (m/s) W-west, S-south 06/02/14 67 19.5 3.1 0 0.5 WN 08/02/14 67.125 22.3 3.6 0 0.25 WN 10/02/14 51.625 22.4 3.5 0 1.375 W,WN,NE,W 12/02/14 44.375 23.1 3.2 0 1.875 N,WN 14/02/14 45 24.2 3.3 0.8 1 W,WN 16/02/14 87.5 17.5 3 0 1.25 W 18/02/14 59.375 20.3 3.4 0 1.75 N,W,WN 20/02/14 58.25 23.4 3.5 0 1.25 W,WN 22/02/14 59.125 23.7 3.2 0 1 W,WN 24/02/14 64 21.8 3.6 0 1.375 W 26/02/14 58.875 23.5 3.4 0 1.25 W,WN Min 44 12 1 0 0 Max 89 24 4 1 3 Mean 70 19 3 0 1

4.4 Traffic volume at the sampling sites The growth rate in the number of motor vehicles in Dhaka as well as Bangladesh, in recent years is quite high (around 8 % on an average for the past 5 years). This is a joint result of a robust economic growth, giving rise to a larger middle class and a lack of good public transport system in Dhaka city. For long distance road is now the major mode of transport, eclipsing rail or water, which are generally more energy efficient. High congestion in the roads of Dhaka and Gazipur not only increases emissions to the atmosphere, but also increases exposure of in-vehicle users as well as pedestrians.

A traffic survey was conducted by manual counting of vehicles in the Farmgate corridor in front of the sampling site and Gazipur crossing on selected days during the study period to understand correlation between pollutant (PM and BC) concentrations and traffic volume. It was observed that the private cars were the main motorized vehicles (80% of the total vehicles) plying along Farmgate corridor and most of them are of CNG driven. Besides this many old minibus, bus, motor cycle, truck and covered vans were also run through the road ways. It was found that, due to some restriction heavy-duty diesel trucks and covered vans operated 5 times [59] more

frequently at night than during the day. Number of registered motor vehicles in Dhaka as well as in Bangladesh (year wise) is shown in Table 4.9 and Table 4.10. From the above stated table it is seen that, about 70 % of the total number of different types of vehicles of the whole country are plying in Dhaka.

Table 4.9: Number of registered motor vehicles in Bangladesh (year wise)

Sl. Up to March Grand No Type of Vehicles 2009 2010 2011 2012 2013 2014 Total 1 Ambulance 2506 287 219 181 243 96 3532 2 Auto Rickshaw 108436 18327 20423 23545 15697 4948 191376 3 Auto Tempo 13977 289 175 626 395 105 15567 4 Bus 26016 1762 1761 1439 1107 306 32391 5 Cargo Van 2911 611 489 282 687 287 5267 6 Covered Van 3760 1898 2354 1421 2271 890 12594 7 Delivery Van 15564 1499 1004 774 894 242 19977 8 Human Hauler 5846 674 1152 715 385 40 8812 9 Jeep(Hard/ Soft) 30162 2124 2134 1569 1314 355 37658 10 Microbus 59404 6975 4051 3044 2537 946 76957 11 Minibus 24749 895 276 249 148 40 26357 12 Motor Cycle 650147 109110 114616 101588 85808 21968 1083237 Pick Up (Double/ 13 23273 8967 10460 7625 6553 2040 58918 Single Cabin) Private Passenger 14 Car 196870 22960 12950 9224 10472 3624 256100 Special Purpose 15 5900 471 396 226 227 68 7288 Vehicle 16 Tanker 2379 327 317 195 226 73 3517 17 Taxicab 44361 19 75 172 51 7 44685 18 Tractor 16855 3745 5200 3494 1885 425 31604 19 Truck 73336 9535 7327 4335 5129 2482 102144 20 Others 934 383 7 1 1080 413 2818 TOTAL 1307386 190858 185386 160705 137109 39355 2020799 (Source: BRTA)

Table 4.10: Number of registered motor vehicles in Dhaka (year wise).

Sl. Type of Vehicles Up to 2010 2011 2012 2013 March Grand No 2009 2014 Total 1 Ambulance 1188 186 137 114 190 77 1892 2 Auto Rickshaw 7612 52 112 111 60 24 7971 3 Auto Tempo 1659 3 1 1 0 0 1664 4 Bus 15552 1231 1501 1218 971 291 20764 5 Cargo Van 2641 590 477 278 676 287 4949 6 Covered Van 2870 1407 1910 1170 1850 722 9929 7 Delivery Van 10788 1202 839 577 709 189 14304 8 Human Hauler 2475 243 569 145 115 12 3559 9 Jeep(Hard/Soft) 18260 1260 1698 1241 1107 309 23875 10 Microbus 40503 5699 3540 2643 2227 833 55445 11 Minibus 9341 149 136 103 83 21 9833 12 Motor Cycle 179383 30698 34708 32810 26331 7141 311071 13 Pick Up 14258 6223 7258 5149 4908 1609 39405 (Double/Single Cabin) 14 Private Passenger 143389 19615 11423 8187 9231 3186 195031 Car 15 Special Purpose 700 59 60 28 78 7 932 Vehicle 16 Tanker 719 98 152 90 136 37 1232 17 Taxicab 36011 0 52 43 4 0 36110 18 Tractor 7151 2772 4169 2841 1634 401 18968 19 Truck 22299 4623 4205 2824 3522 1724 39197 20 Others 113 55 0 0 660 225 1053 TOTAL 516912 76165 72947 59573 54492 17095 797184 (Source: BRTA)

At Gazipur, through the local roads which are very close to the sampling site, most of the vehicles are of 2-stroke petrol, diesel or shallow engine (Nasimon). It is seen that at day time approximately 3000 numbers of different types of vehicles (mostly diesel driven truck, van, pickup etc) ply per hour through Dhaka-Mymemsing road and 1700 numbers of vehicles (mostly 2-stroke baby taxi, motor cycle, mini-bus and human haler using shallow engine) ply per hour through the station road, which is about 400 m north to the sampling site.

Table 4.11: Average number of motor vehicles per hour through station road, Gazipur at day time. Date 2-stroke baby Jeep, Bus , Private car, Motor Truck, taxi, Tempoo, Maxi Mini CNG, Micro cycle Pick up Nasimon bus bus Van (No.) (No.) (No.) (No.) (No.) (No.) 5/2/2014 342 185 126 444 544 156 6/2/2014 355 182 118 435 484 142 7/2/2014 297 185 102 418 432 165 8/2/2014 325 192 109 429 475 148 9/2/2014 357 207 112 428 525 149 10/2/2014 362 191 123 448 531 152 11/2/2014 331 196 117 439 487 154 12/2/2014 344 188 118 432 492 148 13/2/2014 351 187 122 451 479 142 14/2/2014 287 182 102 398 426 158

Figure 4.21: Average numbers of motor vehicles per hour through station road, Gazipur a day time.

Although the number of buses, minibuses, human haulers and trucks are much smaller in comparison to the personal vehicle fleet, these vehicles contribute more to the total particulate emissions. The DoE (2011) roadside measurements found that more than 60 % of the diesel fleet fails to meet free acceleration smoke emissions standard. The primary reasons are an older vehicle fleet with mostly pre-Euro era

68 engines, use of diesel fuel and poorer maintenance of commercial vehicles. Reducing emissions from these vehicles through improved vehicle inspection and maintenance or phasing out of the vehicles from urban centers can have large immediate health benefits in Bangladesh. An important parameter in particulates from motor vehicles is the sulphur content in the fuel. High sulphur content can be particularly harmful for diesel vehicles. At present the sulphur content in motor fuel in Bangladesh is significantly high as compared to many other countries [60] .

Figure 4.22: Personal vehicle fleet in Dhaka

Figure 4.23: Two-stroke three wheelers through station road, Gazipur

CHAPTER-5 CONCLUSIONS 5.1 Conclusions The sources and concentrations of particulate matter and black carbon in the air of Gazipur (Joydebpur) and Dhaka (Farmgate) during winter season are addressed in this study. Sampling was done at semi residential and traffic sites during December 2013 to February 2014. It was our expectation that at Gazipur site the concentration of the pollutants would be low. But the experimental result is quite opposite to our assumption. This study shows that at Gazipur the concentrations of black carbon and

PM2.5 are quite high than that of Dhaka whereas the concentrations of PM10 are high at Farmgate (Dhaka) during the sampling period. It seems that coarse particles emitted from construction activities and road dust contribute in the concentrations of PM10.

Moreover, in the air of Dhaka PM10 also increased by the emissions from diesel based power plants and generators.

At Gazipur, the concentrations of PM2.5 and PM10 are approximately 2.03 times and 1.25 times, respectively higher than the BNAAQS while those concentrations are almost 6.6 times and 3.7 times, respectively higher than the WHO standard. At

Dhaka, the concentrations of PM2.5 and PM10 are approximately 1.79 times and 1.58 times, respectively higher than the BNAAQS while those concentrations are almost 4.66 times and 4.75 times, respectively higher than the WHO standard.

Source apportionment results showed that brick kilns, construction activites, road dust and vehicular exhaust are the main contributor to particulate matter. Meteorological analysis shows the relationship among black carbon, particulate matter and meteorology conditions such as wind speed, wind direction, temperature and humidity. It is found that the concentrations of BC relative to PM2.5 is higher and have good correlation to wind speed and temperature. Thus it is concluded that the main sources of air pollution in the air of Gazipur and Dhaka city are particulate matter arise from combustion sources, motor vehicles and brick kilns. The dominant sources of black carbon are both due to local and regional pollution sources like traffic, coal and biomass burning. Reduction of emission from motor vehicles, brick kilns and soil dust including road dust can made the air clean and pollution free.

5.2 Recommendations Necessary steps should be taken to reduce air pollution in Bangladesh. The air pollutants mainly emit from motor vehicles, brick kilns and soil dust. Thus, to reduce the vehicular and brick kiln pollution the following steps should be taken.

1. Conversion of vehicles to original CNG engines. 2. Reduce the traffic congestion so that the speed of the vehicles can be increased. This will reduce the fuel consumption. Hence pollutants emission will also be decreased and air quality will be improved. 3. Sulfur should be reduced from coal and diesel fuel. 4. The production technology of brick-kiln should be updated. 5. Development of national policies should be taken to reduce and mitigate various emissions from mobile and stationary sources. 6. Strict enforcement of law and legislation should be adopted.

5.3 Suggestions for future work The results found in this study indicate that, the PM level in the ambient air of a residential or semi residential area near a rapidly developing city may not be meet the BNAAQS. Hence 1. Sampling should be carried out to kwon the status of ambient air quality of the rapidly growing other cities of Bangladesh. 2. Seasonal variation of the concentration of the pollutants in the air of growing cities may be studied. 3. Sampling should be carried out to kwon the status of air pollutants due to the emission from brick kilns and also indoor air pollution.

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distribution of ambient PM2.2 and PM10 concentrations in Dhaka, Bangladesh.” The Science of the Total Environment, 2006. 358: p. 36-45 54. S. K. Biswas, S. A. Tarafdar, A. Islam, M. Khaliquzzaman, H. Tervahattu, and K. Kupiainen, “Impact of unleaded gasoline introduction on the concentration of lead in the air of Dhaka, Bangladesh”. J. Air and Waste Management Association 53. 55. B. A. Begum, E. Kim, S. K. Biswas and P. K. Hopke; “Investigation of sources of atmospheric aerosol at urban and semi-urban areas in Bangladesh by positive matrix factorization” Atmos. Environ. (UK), 38, (2004), 3025-3038. 56. B. A. Begum, S. K. Biswas and P. K. Hopke; “Identification of potential source

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Appendix- 1: National Ambient Air Quality Standards for Bangladesh

Pollutant Objective Average CO 10 mg/m3 (9 ppm) 8 hours(a) 40 mg/m3 (35 ppm) 1 hour(a) Pb 0.5 µg/m3 Annual 3 NOx 100 µg/m (0.053 ppm) Annual PM10 50 µg/m3 Annual (b) 150 µg/m3 24 hours (c) PM2.5 15 µg/m3 Annual 65 µg/m3 24 hours 3 O3 235 µg/m (0.12 ppm) 1 hour (d) 157 µg/m3 (0.08 ppm) 8 hours 3 80 µg/m (0.03 ppm) Annual 3 SO2 365 µg/m (0.14 ppm) 24 hours (a)

(Source: AQMP, DOE). Notes: (a) Not to be exceeded more than once per year (b) The objective is attained when the annual arithmetic mean is less than or equal to 50 ug/m3 (c) The objective is attained when the expected number of days per calendar year with a 24-hour average of 150 µg/m3 is equal to or less than 1. (d) The objective is attained when the expected number of days per calendar year with the maximum hourly average of 0.12 ppm is equal to or less than 1.

Appendix -II: Gaseous composition of dry air

Constituent Chemical symbol Mole percent

Nitrogen N2 78.084

Oxygen O2 20.947 Argon Ar 0.934

Carbon dioxide CO2 0.0350 Neon Ne 0.001818 Helium He 0.000524

Methane CH4 0.00017 Krypton Kr 0.000114

Hydrogen H2 0.000053

Nitrous oxide N2O 0.000031 Xenon Xe 0.0000087

Ozone* O3 trace to 0.0008 Carbon monoxide CO trace to 0.000025

Sulfur dioxide SO2 trace to 0.00001

Nitrogen dioxide NO2 trace to 0.000002

Ammonia NH3 trace to 0.0000003

Appendix –III Experimental data obtained from this study

3 (a) Concentrations of PM2.5 (µg/m ) in Gazipur (Joydebpur) and Dhaka (Farmgate)

December-2013 January-2014 February-2014

Gazipur Dhaka Gazipur Dhaka Gazipur Dhaka 110.28 40.42 80.93 70.32 89.35 40.28 Min (04/12/2013) (26/12/2013) (09/01/2014) (17/01/14) (26/02/14) (16/02/2014) 185.51 243.55 208.66 246.53 157.55 150.66 Max (20/12/13) (20/12/13) (17/01/14) (03/01/2014) (18/02/14) (06/02/2014)

Mean 146.71 123.74 131.52 121.96 119.94 94.17 Three months (December 2013 to February 2014) average for Dhaka- 114 µg/m3. Three months (December 2013 to February 2014) average for Gazipur- 132.65 µg/m3

3 (b) Concentrations of PM10 (µg/m ) in Gazipur (Joydebpur) and Dhaka (Farmgate)

December-2013 January-2014 February-2014 Gazipur Dhaka Gazipur Dhaka Gazipur Dhaka 177.58 201.53 178.85 87.27 156.53 89.40 Min (24/12/2013) (28/12/2013) (31/01/2014) (17/01/2014) (10/02/2014) (16/02/14) 196.18 416.59 285.50 363.47 173.34 266.26 Max (06/12/13) (22/12/13) (19/01/14) (05/01/14) (02/02/2014) (20/02/14) Mean 189.48 285.93 200.43 202.59 163.57 188.40 Three months (December 2013 to February 2014) average for Dhaka- 227 µg/m3. Three months (December 2013 to February 2014) average for Gazipur- 185.80 µg/m3

December-2013 January-2014 February-2014

Gazipur Dhaka Gazipur Dhaka Gazipur Dhaka 41.64 12.25 42.55 18.13 53.45 11.17 Min (02/12/2013) (26/12/2013) (15/01/2014) (15/01/2014) (02/02/2014) (16/02/2014) 116.30 40.67 90.19 35.94 108.13 44.47 Max (14/12/2013) (08/12/2013) (23/01/2014) (09/01/2014) (18/02/2014) (06/02/2014)

Mean 80.13 31.11 66.59 24.92 74.08 25.84 Three months (December 2013 to February 2014) average for Dhaka- 27.2 µg/m3. Three months (December 2013 to February 2014) average for Gazipur- 73.72 µg/m3

(d) Total Experimental data obtained from the study

Dhaka Gazipur Met Data

Date PM10 PM2.5 BC PM2.5 BC PM10 PM2.5 BC PM2.5/ BC Humidity Temp Visibility Rain fall WS Wind direction 3 3 3 3 3 3 o 0 µg/m µg/m µg/m /PM10 /PM2.5 µg/m µg/m µg/m PM10 /PM2.5 (%) ( C) (km) (mm) (m/s) (degree) 02/12/13 208.56 102.84 29.68 0.49 0.29 190.46 157.50 41.64 0.83 0.26 65.875 21.8 3.4 0 0.75 NW 04/12/13 235.40 72.45 35.37 0.31 0.49 193.4 110.28 85.42 0.57 0.77 69.25 22.2 4.4 0 0.5 WN 06/12/13 309.54 83.63 29.19 0.27 0.35 196.18 147.92 96.51 0.75 0.65 70.375 20.2 4 0 0 NW 08/12/13 217.08 77.88 40.67 0.36 0.52 196.13 145.37 89.04 0.74 0.61 68.75 19.7 3.6 0 0.25 N 10/12/13 208.77 106.44 29.80 0.51 0.28 194.39 132.64 87.92 0.68 0.66 71.875 19.8 1.7 0 1 NE 12/12/13 392.00 184.31 35.62 0.47 0.19 195 151.57 92.60 0.78 0.61 67.125 19.1 0.8 0 0 N,E 14/12/13 286.74 188.09 36.83 0.66 0.20 190.56 140.56 116.30 0.74 0.83 70.625 21 2.6 0 0.5 N 16/12/13 245.11 115.40 31.06 0.47 0.27 189.31 127.31 89.80 0.67 0.71 68.75 21.2 3.2 0 0.5 N 18/12/13 257.65 133.33 38.50 0.52 0.29 188.67 133.10 72.34 0.71 0.54 69.5 17.9 1.8 0 0.25 N 20/12/13 359.98 243.55 34.91 0.68 0.14 188.15 185.51 66.38 0.99 0.36 80.125 17 1.4 0 0.5 WNW,W 22/12/13 416.59 125.60 30.27 0.30 0.24 181.03 169.35 71.84 0.94 0.42 80.625 14.6 1.8 0 0 WN,N,W, 24/12/13 401.27 129.26 26.34 0.32 0.20 177.58 134.86 78.19 0.76 0.58 68.125 15.6 2.9 0 1.625 WN,W,WN,WS 26/12/13 340.65 40.42 12.25 0.12 0.30 180.23 162.50 69.70 0.90 0.43 73.625 14.8 2.1 0 1.125 NE 28/12/13 201.53 121.94 29.20 0.61 0.24 188.2 174.86 75.42 0.93 0.43 84.25 14 1.6 0 0 N,WN 30/12/13 208.00 131.00 27.00 0.63 0.21 192.74 127.36 68.79 0.66 0.54 72.5 16 2.3 0 0.25 WN 01/01/14 246.30 109.07 26.02 0.44 0.24 198.69 88.43 85.42 0.45 0.97 63.625 18.4 2 0 0.75 E

Dhaka Gazipur Met Data

Date PM10 PM2.5 BC PM2.5 BC PM10 PM2.5 BC PM2.5/ BC Humidity Temp Visibility Rain fall WS Wind direction 3 3 3 3 3 3 o 0 µg/m µg/m µg/m /PM10 /PM2.5 µg/m µg/m µg/m PM10 /PM2.5 (%) ( C) (km) (mm) (m/s) (degree) 03/01/14 271.02 246.53 20.17 0.91 0.08 197.29 125.37 64.71 0.64 0.52 66 20 1.8 0 1.25 WN 05/01/14 363.47 207.22 32.18 0.57 0.16 194.3 133.70 74.37 0.69 0.56 76.875 20 1.8 0 1 WN 07/01/14 241.48 143.24 24.45 0.59 0.17 195.59 183.29 75.69 0.94 0.41 77.5 21.3 2.5 0 0.5 NE.WN 09/01/14 324.49 210.97 35.94 0.65 0.17 198.88 80.93 63.31 0.41 0.78 87 12.5 2.9 0 0.75 WN,W,WN 11/01/14 179.49 71.20 25.41 0.40 0.36 194.1 81.02 65.75 0.42 0.81 63.125 12.3 1.3 0 0.5 WN 13/01/14 161.09 113.64 20.38 0.71 0.18 197.02 135.88 47.89 0.69 0.35 67.875 15.8 2.7 0 1.625 N,WN 15/01/14 112.69 93.33 18.13 0.83 0.19 202.38 129.35 42.55 0.64 0.33 88.5 17.6 2.5 0 0.75 N 17/01/14 87.27 70.32 22.82 0.81 0.32 219.74 208.66 73.34 0.95 0.35 84.5 18.5 2.5 0 1.125 N 19/01/14 205.20 86.01 22.31 0.42 0.26 225.5 97.63 78.19 0.43 0.80 72 20 3.1 0 1.25 WN 21/01/14 192.34 166.39 32.45 0.87 0.20 219.5 130.14 54.85 0.59 0.42 85.125 21.5 3 0 2.25 N,WN,W,WN 23/01/14 156.94 72.82 20.34 0.46 0.28 208.52 184.21 90.19 0.88 0.49 66.125 19.4 3.6 0 0.5 WN,W,WN 25/01/14 161.00 76.40 21.50 0.47 0.28 200.69 120.88 55.49 0.60 0.46 61.125 18.5 3 0 1.375 W,N,WN,W 27/01/14 158.30 81.60 23.20 0.52 0.28 190.82 125.65 44.09 0.66 0.35 70 20.2 2.9 0 2.625 W,WN,W 29/01/14 180.80 80.59 28.42 0.45 0.35 184.94 147.64 83.08 0.80 0.56 67.375 19.4 2.9 0 0.75 WN,W 31/01/14 199.58 98.03 21.51 0.49 0.22 178.85 103.70 50.64 0.58 0.49 81 18.5 2.9 0 1.5 N 02/02/14 145.21 112.03 20.96 0.77 0.19 173.34 132.04 53.45 0.76 0.40 66.25 16 2.5 0 2 N 04/02/14 194.17 130.42 21.45 0.67 0.16 166.72 150.88 56.80 0.90 0.38 77.125 16.3 3.2 0 1.25 W 06/02/14 258.49 150.66 44.47 0.35 0.30 166.32 121.23 99.85 0.73 0.82 67 19.5 3.1 0 0.5 WN

Dhaka Gazipur Met Data

Date PM10 PM2.5 BC PM2.5 BC PM10 PM2.5 BC PM2.5/ BC Humidity Temp Visibility Rain fall WS Wind direction 3 3 3 3 3 3 o 0 µg/m µg/m µg/m /PM10 /PM2.5 µg/m µg/m µg/m PM10 /PM2.5 (%) ( C) (km) (mm) (m/s) (degree) 08/02/14 170.57 93.48 17.25 0.55 0.18 160.7 95.79 60.10 0.60 0.63 67.125 22.3 3.6 0 0.25 WN 10/02/14 170.22 80.42 28.64 0.47 0.36 156.53 98.94 72.58 0.63 0.73 51.625 22.4 3.5 0 1.375 W,WN,NE,W 12/02/14 264.77 87.45 27.58 0.33 0.32 162.35 95.42 66.38 0.59 0.70 44.375 23.1 3.2 0 1.875 N,WN 14/02/14 248.29 58.52 23.15 0.24 0.40 164.24 106.11 61.58 0.65 0.58 45 24.2 3.3 0.8 1 W,WN 16/02/14 89.40 40.28 11.17 0.45 0.28 163.1 133.47 67.46 0.82 0.51 87.5 17.5 3 0 1.25 W 18/02/14 121.60 56.80 19.20 0.47 0.34 160.2 157.55 108.13 0.98 0.69 59.375 20.3 3.4 0 1.75 N,W,WN 20/02/14 266.26 132.79 39.27 0.50 0.30 158.73 114.49 89.80 0.72 0.78 58.25 23.4 3.5 0 1.25 W,WN 22/02/14 115.31 90.24 25.32 0.78 0.28 160.3 129.21 75.16 0.81 0.58 59.125 23.7 3.2 0 1 W,WN 24/02/14 182.40 84.36 30.87 0.46 0.37 165.2 134.77 97.44 0.82 0.72 64 21.8 3.6 0 1.375 W 26/02/14 221.81 106.71 26.60 0.48 0.25 168.72 89.35 54.31 0.53 0.61 58.875 23.5 3.4 0 1.25 W,WN

Min 87.3 40.3 11.2 0.12 0.08 156.53 80.93 41.6 0.00 0.26 44 12 1 0 0 0 Max 428 247 44.5 0.91 0.52 225.50 208.66 116 0.99 0.97 89 24 4 1 3 0 Mean 227 114 27.2 0.52 0.27 185.80 132.65 73.1 0.72 0.57 70 19 3 0 1 STD 87.4 49.4 7.36 0.17 0.09 17.47 29.55 17.6 0.19 0.17 10.2 3.0 0.8 0.1 0.6 Median 209 105 26.8 0.49 0.27 189.89 132.34 72.5 0.71 0.57 69 20 3 0 1

Appendix-IV: News paper reports in support of the study

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Appendix-V: Publications from the thesis.

1. “Black Carbon Contribution in Dhaka City Air During Winter” B. A. Begum, M. M. Hoque, A. M. Shawan, A. K. M. L. Rahman and S. J. Ahmed; Nuclear science and applications, Vol. 22 No.1&2, 2013. 2. “Particulate Matter Concentrations in the Air of Dhaka and Gazipur City During Winter: A comparative study” M. M. Hoque, B. A. Begum, A. M. Shawan and S. J. Ahmed; International Conference on Physics for Sustainable Development &Technology (ICPSDT-2015), CUET.

NUCLEAR SCIENCE AND APPLICATIONS Short Communication Vol. 22. No. 1&2, 2013

Black Carbon Contribution in Dhaka City Air During Winter

B.A. Begum1, M.M. Hoque,2A.M. Shawan3, A.K.M. Lutfur Rahman1 and S.J. Ahmed2

1Chemistry Division Atomic Energy Center, Dhaka 2Dhaka University of Engineering and Technology, Gazipur-1700 3Department of chemistry, Jagannath University, Dhaka-1100

The main contribution of black carbon emission in air is motor vehicles and brick kilns. In addition meteorological condition during the winter cause increase in the fine particulate matter (PM) concentration by factor of 4 to 5 compared to PM concentration in the rainy season. To understand the black carbon pollution status of the Dhaka area, both the PM2.5and PM10 fractions were collected between December 2013 and February 2014 from a semi-Residential site (AECD campus) and CAMS-2 site and the results were compared with the previous date. It was found that although PM2.5 and PM10 has decreased compared to that of the period 2009-2011 to 2012-13, but the ratio of BC/PM has increased compared to the previous year. This increase of BC/PM ratio due to unstable political situation. In December 2012 and In December 2013, the number of motor vehicles running in the city streets were less due to useable political situation and therefore the communication of black carbon from motor vehicles were less. But the emissions from bricks kilns remained similar. As brick kilns were one of contribution of black carbon (BC) emission hence the ratio of BC/PM was high considering slight contribution of long range transport.

Keywords: PM10, PM2.5 BC, long range transport.

Particulate matter pollution of air is of much concern in together with this trans boundary pollutants increase the major cities in Bangladesh. The main contributors of particulate pollution level in Bangladesh [5]. On the other these pollutions are motor vehicles, brick kilns, diesel hand, particulate pollution level goes down during generators and small industrious. The situation is same to monsoon due to frequent rainfall. The aim of this study is Dhaka city. Fine particulate matter with aerodynamic to understand the nature and source of BC emission over diameter less than 2.5µm is a widespread air pollution Dhaka city during winter. problem. In Dhaka, the daily average of PM2.5 level usually exceeds the Bangladesh national ambient air Sampling and site description quality standard (NAAQS) of 65ug/m in winter although The CAMS-2 site is located at Farm Gate (Fig.1) in they meet the requirements during the monsoon season. Dhaka city. Farm Gate is a hot spot site due to the As a result, in winter, the annual average never can proximity of several major roadways intersection and comply with the national standard of 15ug/m. The large number of vehicle plying through the area (6). The concentrations of trace gases, including key primary site is surrounded by commercial and semi industrial pollutant and ozone were monitored in ambient air in areas. The samplers were placed on the flat roof of the Dhaka and were found to comply with the National guardhouse of Bangladesh Agriculture Research Council Ambient Air Quality Standard [1]. Previous studies of (BARC). This location also houses the second continuous Dhaka air quality shows major fractions of the PM2.5 is air monitoring station (CAMS) in Dhaka. The minivols black carbon (BC) [2,3]. The emission of BC and sulfur were programmed to sample at 5 1pm through PM10 and comes from diesel (heavy duty vehicles), household solid PM2.5 particle size separators (impactors) and then fuel combustion and brick kilns where coal is used fuel. through 2 um pore Teflon filters [7]. Atomic Energy Public buses. Private cars, and 3-wheel Taxis, which Center, Dhaka (AFCD) of BAEC was the others sampling mainly run during daytime are operated on compressed site (semi-residential) for collecting PM samples using a natural gas (CNG). Heavy-duty diesel vehicle ply on the ‘gent’ stacked filter sampler (8). Capable of collecting air roads primarily during the night (10 PM to & AM) particulate, samples in coarse (2.5-10 um) and fine (2.5 because of restrictions imposed to reduce traffic um) size fractions together PM10 concentration may be congestion. It has been found in deferent studies that obtain by adding PM2.5 and PM10-2.5 concentration about 85% of total vehicle fleet during the day in Dhaka generally, the samples were collected for a 24 h average is private cars. Their density is high on weekdays. About period at least twice on a week (only holidays). In the 18% of total vehicle are trucks that run though this area at semi residential area (SR) site the samples was placed on night. Because of frequent power failures, diesel the flat roof of the Atomic Energy Center, Dhaka (AFCD) generators are used extensively to meet the electricity campus building. The roof height was 5 m and the intake demand. These diesel generators, heavy- duty vehicles nozzle of the sampler was located 1.8 m above the roof. and brick kilns emit carbonaceous particles and are The intake was about 80 m away from outside. The important contributors to ambient PM2.5concentrations. sampler was placed in such a way that the airflow around Trans boundary pollutant transport was expected to be it was unobstructed. high during wintertime [4]. Hence local pollutants The sampling protocol was continued from December 02, 2013 to February 27,2014 during winter time period. The Correspondence author: [email protected] conditioned clean filter were loaded to respective filter 59

NUCLEAR SCIENCE AND APPLICATIONS Short Communication Vol. 22. No. 1&2, 2013 holder assembly at the CAMS-2 conditioning room and um) are then collected on 0.4 µm filter [10]. The were brought to sampling site in separate clean dry test meter (volume meter) built into the system polyethylene bags at each effective sampling day. After directly measures the total volume of air sampled by this sampling, the filter holder assembles (keeping the unit. This GENT sampler in two fractions namely coarse exposed filter inside) were brought to the conditioning (PM10-2.5) and fine (PM2.5). Details of the sampling room of AECD directly from the sampling site for method may be seen elsewhere [11]. conditioning and PM retrieval. Care was taken in transporting the exposed filter holder assembles so that there should be no loss. Meteorological condition In Bangladesh, the climate is characterized by high temperature, high humidity most of the year and distinctly marked seasonal variation of precipitation. According to meteorological condition, the year can be divided into four seasons, pre-monsoon (March- May), monsoon (June-September), and post-monsoon (October-February) [12]. As the dispersion of PM strongly depend on the wind speed and direction, the meteorological data for dates of samples collection was collected from the nearby meteorological station, which is located about 2 kilometers east of the sampling site.

Measurement of PM mass and black carbon (BC) PM mass was measures in the Chemistry lab of the Atomic Energy Center, Dhaka (AECD). The PM10 and PM2.5 sample were determined by weighing the filters before and after exposure using a microbalance [13]. The filters were equilibrated for 24th at constant humidity of Figure 1: Map of sampling site, (Farmgate, Dhaka) 50% and temperature (22C) in the balance room before each weighting A Po—210 (alpha emitter) electronic

charge eliminator was used to eliminate the static charge Description of samplers accumulate in the filter before each weighing. The Air matrics sampler difference in weights for each filter was calculated and The air matrics mini Vol. sampler developed jointly by the mass concentrations for each PM10 or PM2.5 samples the U.S Environmental Protection Agency EPA) and the were determined. The concentration of BC in the PM10 lane Regional Air Pollution Athority was used for both samples was determined by reflectance measurement in AFCD laboratory using an Evens Electro selenium PM10 and PM2.5 sampling (9) from CAMS -2, located at Farmgate site, (Fig.1) in Dhaka city. Limited (EEL) type Smoke Stain Refplectometer (14). Secondary standards of known black carbon Gent sampler concentrations were used to celebrate the reflect meter. The air enters the unit though an impactor stage designed to have 50 % collection efficiency at 10 µm equivalent PM and BC distribution in Dhaka city during winter aerodynamic diameter. Then air is drawn through a Dhaka the eight largest mega city of the world, witnessed stacked-filter unit (SFU), which consist of a holder for a very fast growth of urban population in recent times two sequential filters constructed by the Norwegian which contributed to rising demand for transport service, Institute for Air Research (NILU). The initial filters were mainly the road transport. With the economic 8 µm pore and 47 µm Nuclepore filter and the second development, the numbers of motor vehicle have increase filter was a 0.4 µm pore Nuclepore filter. According to in an uncontrolled manner and this make the major traffic the design specification at a flow rate for 16 filters per intersection in the city into hot spots for air pollution due minute (1 pm), the unit should act as a dichotomous to vehicular emission. Motorized transport of Dhaka are sampler, which is an accepted USEPA FRM (Federal. suspected to be the second largest contributor of air Recommended Method) sampler. In such a condition the pollution in Dhaka [7,15] in Dhaka, most of vehicles run flow through the 8 µm pores will result in the collection by CNG fuel during daytime, at night time heavy duty of 22 um particles with 50% efficiency and the one {(-22 vehicles run by diesels. It is known that diesel exhaust

NUCLEAR SCIENCE AND APPLICATIONS Short Communication Vol. 22. No. 1&2, 2013 contains harmful gases, liquid droplets and solid particles. Table 2. Basic statistics of ratios PM2.5/PM10 and The majorities of the particles are sub-micron in size and BC/PM2.5 during December 2011 to February 2012. are considered to be the most damaging to human health. The pollutants of concern found in diesel exhaust are PM, CAMS-2 site SR site NO hydrocarbon toxins such as polynuclear aromatics. The primary particles are emitted directly by vehicles, Parameter PM2.5// BC/ PM2.5/ BC/ secondary particles are formed from the chemical PM10 PM2.5 PM10 PM2.5 oxidation of atmospheric gases. Oxides of solphur and of Min 0.30 0.17 0.05 0.11 nitrogen are precursors for secondary particles, reducing Max 0.79 0.17 0.46 0.55 in diesel could lower the amount the sulphate-based particles. On the other hand, CNG vehicles also emit Mean 0.62 0.10 0.25 0.23 particles in sub-micron range which also harmful for SD 0.11 0.02 0.13 0.11 human. Median 0.61 0.10 0.22 0.19 Therefore the assessment focuses on the particles mass concentration data in the last four winter season, Again table 3 & 4 the ratios of PM10 and BC/PM2.5 in December 10 to February 11, December 11 to February two sites during winter time of December 2012 to 12, December 12 to February 13, and December 13 to February 2013 and December 2013 to February 2014. February 114. Table 1 & 2 provide the rations of PM2.5 From table 3 & 4 it was found that PM2.5 contribution /PM10 andand BC/PM2.5 in two sites during winter time almost remain same. As a result, BC/PM2.5 is less of December 2010 to February 2011 and December 2011 contribution of vehicular emissions. During the period of to February 2012. It was found that PM2.5 contributions December 2012 to February 2013 and December 2013 to is high and BC contribution is less than that of February 2014, there were strikes on vehicular movement. PM2.5/PM10 ratio. From the previous source Hence the number of motor vehicles that were on road apportionment studies [5], it was found that due to CNG was only 5% of the total fleet. The bricks kilns adaptation as fuel in motor vehicles, the emission of BC contributions remain as in the previous year. If the from motor vehicles has reduced. The main contributor of emission from brick kilns can be reduced, the BC BC in the air over Dhaka city remain to brick kilns emission would be reduced. The government is trying to scattered the city area [5]. change the existing brick production technology but now it is in pilot stage. Table 1. Basic statistics of ratios PM2.5/PM10 and

BC/PM2.5 during December 2010 to February 2011. Table 3. Basic statistics of ratios PM2.5/PM10 and

BC/PM2.5 during December 2012 to February 2013. CAMS-2 site SR site

CAMS-2 site SR site Parameter PM2.5// BC/ PM2.5/ BC/

PM10 PM2.5 PM10 PM2.5 Parameter PM2.5// BC/ PM2.5/ BC/

PM10 PM2.5 PM10 PM2.5 Min 0.08 0.06 0.14 0.04 Min 0.33 0.11 0.08 0.06

Max 0.60 0.75 0.49 0.49 Max 0.97 0.43 0.55 0.24 Mean 0.45 0.12 0.31 0.26 SD 0.31 0.14 0.11 0.10 Mean 0.74 0.23 0.33 0.15 Median 0.51 0.08 0.31 0.23 SD 0.14 0.09 0.12 0.05 Median 0.77 0.20 0.35 0.15

NUCLEAR SCIENCE AND APPLICATIONS Short Communication Vol. 22. No. 1&2, 2013

Table 4. Basic statistics of ratios PM2.5/PM10 and 3. B.A. Begam, S.K. Biswas, A Markwics and P.K.

BC/PM2.5 during December 2013 to February 2014. Hopke, identification of sources of fine and coarse particulate mater In Dhaka, Bangladesh, Aerosol andAir Quality Research. 10345-353 CAMS-2 site SR site (2010) 4. B.A. Begam, S.K. Biswas, G.G. Pandit, I.V. Parameter PM2.5// BC/ PM2.5/ BC/ Saradhib, S. Waheed, N. Siddiquec, MCS. PM10 PM2.5 PM10 PM2.5 Seneviratne, D.D. Cohen, A. Markwics and P.K. Min 0.12 0.08 0.17 0.04 Hopk, Long Range Transport of Soil Dust and Smoke Pollution in the South Asian Region, Min 0.12 0.08 0.17 0.04 Atmospheric Pollution Research, 2. 151-157 Max 0.91 0.52 0.91 0.32 (2011) 5. B.A. Begam, P.K. Hopke, and A. Markwitz, Air Mean 0.52 0.26 0.46 0.20 pollution by fine particulate matter In SD 0.18 0.09 0.22 0.08 Bangladesh, Atmospheric Pollution Reseearch, 4,75-86 (2013) Median 0.49 0.26 0.42 0.21 6. B.A. Begam, S.K. Biswas, E. kim, P.K. Hopke, and M. Khaliquzzama, investigation of source of The variations of PM2.5/PM10 and BC/PM2.5 between atmosphere aerosol at a hot spot area in Dhaka, two sites are due to the deference of the anthropogenic Bangladesh, J. Air and Waste Management activities between two sites. CAMS-2 site is surrounded Associate, 55,227-240 (2005) by commercial activities whereas Semi-residential (SR) 7. B.A. Begam,M. Nasiruddin, S. Randal, B. sites is located in Dhaka University campus. As a result, Sivertsen and P.K. Hopke, identification and PM2.5 is less in SR sites compared to CAMS-2 sites. So Apportionment of sources from Air Particulate the ratio of BC/PM2.5 is higher in SR sites compared to Matter at Urban Environment in Bangladesh, CAMS-2 site. Submitted (2014) 8. P.K. Hopke, Y. Xie, T. Raunemaa, S. It was found that due to same socio-political Landsberger,, W. Maenhaut, P. Artaxo and D. circumstances, the number of motors were less in the Cohen, Characterization of Gent stacked filter winter. As a result, PM2.5 emission also decreased. Now unit PM10 sampler, Aerosol Science and if the government tries to control the PM emission from Technology, 27,726-735 (1997) brick kilns, it will give positives impact on the air quality 9. R.W. Baldauf, D.D. Lane and G.A. Martz, over Dhaka city area. Ambient Air quality Monitoring Netwark Design for Assessing Human Health Impacts from Acknowledgement Exposures to Airborne Contaminants, The author thankfully acknowledgements the Head of Environmental,66,63-76 (2001) chemistry division , and as well as the department of 10. T.A. Cahill, R.A. Elderd, J.B. Barone and L.L. Environment to gives as permission for sampling at Ashbang, Ambient aerosol samplingwith stacked CAMS-2 site. filter units, 73 (1979) 11. B.A. Begam and S.K, Biswas, Comparison of Reference PM collection efficiency of Gent and Airmatrics MinVol portable Air Sampler, Nuclear Science 1. Suthawaree, HASE jones, S. Kano, H. Kunimi, and Application, 14,79-83 (2005) ANMH Kabir and Y. Kajii, influence of 12. A. Salim, H. Bauer, K. Kassim, S.M. |Ullah intensive compressed natural gas (CNG) usage andH. Puxbaun, Aerosol chemical characteristics on air quality, Atmospheric Environment, of a mega-city in Southeast Asia, Dhaka, 54,296-307 (2012) Bangladesh, Atmospheric Environment, 2. B.A. Begam, E. kim, S.K. Biswas and P.K. 37,2517-2528 (2003) Hopke, investigation of sourws of atmospheric 13. B.A. Begam, S. Akhter, L. Sarkar and S.K. aerosol at urban and semi-urban areas in Biswas, Gravimetric analysis of Air filters and Bangladesh, Atmospheric Environment, Quality assurance in Weighting, Nuclear Science 38,3025-3038 (2004) and Applications, 15,36-41 (2006)

NUCLEAR SCIENCE AND APPLICATIONS Short Communication Vol. 22. No. 1&2, 2013

16. P.C. Kunda, B. Tarafdar, M.R.U. Molla and S.R. 14. S.K. Biswas, S.A. Tarafdat, A. Islam,M. Hayat, Radside vehicle emission testing program Khaliquzzaman, H. Tervahattu and K. in Dhaka, AQMP-DoE: TECDOC NO- Kupiainen, Impact fo unleaded gasoline 01/06(2006). introduction on the concentration of lead in the air of Dhaka, Bangladesh, J. Air and Waste Management Association, 53,1355-1362 (2003) 15. M. Khaliquzzaman, An Assessment of the Impact of Removal of Baby Taxxis on Air Quality in Dhaka, Personal Communication, Consultant, World Bank, Dhaka Office (2003)

Page 140

Particulate Matter Concentrations in the Air of Dhaka and Gazipur City During Winter: A comparative study

M. M. Hoque1*, B. A. Begum2, A. M. Shawan3 and S. J. Ahmed1

1Department of Physics, Dhaka University of Engineering and Technology,Gazipur-1707, Bangladesh. 2Chemistry Division, Atomic Energy Center. P.O. Box No. 164, Dhaka-1000, Bangladesh. 3Department of Chemistry, Jagannath University, Dhaka-1100,Bangladesh.

*Corresponding author: [email protected]

Abstract:

The particulate matter (PM2.5 and PM10) concentrations in the air of Dhaka and Gazipur cities during December, 2013 to February, 2014 have been studied. The PM status and the sources of air pollution in these cities have been investigated. Sampling was done by Air Matrices Mini Vol. Sampler and the quantity of PM2.5 and PM10 was detected by weighing the filters before and after exposure. The sampling sites are Farmgate of Dhaka (CAMS-2 site), a very busy traffic point and Joydeppur of Gazipur (CAMS-4 site), a semi-residential area. The concentrations of particulate matter samples were determined by reflectance measurement. Basic statistic ratios of PM2.5 and PM10 have been analyzed. The concentrations of PM2.5 and PM10 were not significantly changed with respect to that of previous years. Though Farmgate of Dhaka is a very busy traffic point and Joydeppur of Gazipur is a semi- residential area, the concentrations of PM2.5 and PM10 in the air of Joydebpur (Gazipur) has been found higher than that of Farmgate (Dhaka) during the sampling period and the daily average of PM2.5 for both the cities always exceeded the Bangladesh National Ambient Air Quality Standard (BNAAQS, 3 65 µg/ m for PM2.5). Brick kiln emission and long range transports may increase the concentrations particulate matter in the air of Gazipur compared to that of Dhaka. Moreover, there may be an impact of indoor air pollution on the air quality of Gazipur city.

Keywords: PM10, PM2.5, BNAAQS, CAMS-2, CAMS-4

P-ID 93 International Conference on Physics Sustainable Development & Technology (ICPSDT-2015) (August 19-20, 2015) Department of Physics, CUET. Page 141

1. INTRODUCTION

Particulate matter pollution is a major concern in the large cities of Bangladesh. The main contributors of air pollution are motor vehicles, brick kilns, diesel generators and industries. In recent years much research interest has been shown on atmospheric particles as they influence on climate change and cause adverse health effects [1-6]. Although significance of particulate matter in atmospheric and environmental process is pronounced, our knowledge, especially in Bangladesh, on their concentration and sources are inadequate. Rapid industrialization and economic development occurred in Dhaka and Gazipur cities during the recent years which may increase the emission of various pollutants. Bilkis et al. have studied the source identification of particulate matter during winter months in Dhaka city [4] and at urban and semi-urban areas [5] in Bangladesh by positive matrix factorization. They found the contribution from elemental carbon fraction at Farmgate which in comparison to Aminbazar is less. Because, at Farmgate, only the city vehicles ply on road and during the day time mostly 80% of the vehicles are of duel-fueled engine. Particle sources (from coal and biomass burning in brick field) impacts may be contributing haze at urban and semi-urban areas of Bangladesh.

Fine particulate matter with aerodynamic diameter less than 2.5 µm is a widespread air pollution object. Dhaka, the eighth largest city in the world, has witnessed a rapid growth of urban population in recent times. As a result, the number of motor vehicles increased significantly in Dhaka, there has been a steep rise in a heterogeneous mixture of old technology vehicles despite that the road space is narrowing and the traffic congestion is reaching in unmanageable proportions. As a result major traffic intersections in the city have turned to hot spots for air pollution from vehicular emissions. Gazipur, a new city corporation is considered as one of the industrially developed city in Bangladesh. High particulate matter (PM) levels and poor visibility in winter time have become a serious problem there. Coal and biomass burning in brick field, vehicle exhaust, industrial and residential emissions contribute to the ambient PM in this city. During winter season brick kilns goes in operation. The pollution due to vehicles and brick kilns is then expected to be high during winter. To our knowledge, the measurement on the pollution sources and concentration of particulate matter in the air of Gazipur city are not yet reported. In this work, sampling was performed by gravimetric method and the concentration and sources of particulate matter (PM2.5 and PM10) in two locations, Farmgate and Joydebpur of Dhaka and Gazipur cities respectively, will be addressed and compared.

P-ID 93 International Conference on Physics Sustainable Development & Technology (ICPSDT-2015) (August 19-20, 2015) Department of Physics, CUET. Page 142

2. MATERIALS AND METHOD

2.1 Sampling Sites and Sampling of PM2.5 and PM10

Sampling was done in two locations, Farmgate of Dhaka city and Joydebpur of Gazipur city. Farmgate is a hot spot site due to the proximity of several major roadways intersection and large numbers of vehicles plying through this area [7]. The site is commercial as well as semi industrial area. The Tejgaon industrial area is very near to this site. At Farmgate, the samplers were placed on the flat roof of the guardhouse of Bangladesh Agricultural Research Council (BARC). This location houses the second continuous air monitoring station (CAMS-2) at Dhaka. Gazipur is a residential area of moderate population density. The sampling location is within 20 m from a local road and about 200m from a secondary road with moderate traffic density. At Gazipur, the samplers were placed on the flat roof of the continuous air monitoring station (CAMS-4) site of Clean Air and Sustainable Environment (CASE) project, situated at Gazipur city corporation central symmetry, East Chandana, Joydebpur. The Joydebpur Chourasta, which is a very busy traffic point, is about 5 km west to this site. Joydebpur rail station, through which daily 60 trains pass away, is about 100m away from the sampling location. At “Konabari” and “Kodda” which are about 5 to 7 km to the north-west of the sampling site, more than 100 brick kilns are in production using kindle wood. There are many garments and other industries at 4 to 7 km distance from this site.

Particulate matter sampling was performed by using Air Metrics Mini Vol. sampler [8] for collecting both PM10 and PM2.5 samples from the Farm Gate site in Dhaka city and Joydebpur in Gazipur City. The Mini Vol. were programmed to sample at 5 liter per minute through PM10 and PM2.5 particle size separators (impactors) and then through 2m pore teflon filters. The actual flow rate should be 5 liter per minute at ambient conditions for proper size fractionation. To ensure a constant flow of 5 liter per minute through the size separator at different air temperatures and ambient pressures, the sampler flow rates were adjusted for the ambient conditions at the sampling site. The Mini Vol. sampler was positioned with the intake upward and located in an unobstructed area at least 30 cm from any obstacle to air flow and the sampler inlet was placed at a height of 10 m above ground level. The intake nozzle of the samplers at the Farmgate location was about 5 m away from the main road. PM10 and PM2.5 were collected simultaneously for 24 hours average with two Mini Vol. samplers. The inlets of the samplers were kept 45 cm apart from each other. The sampling was continued for three months, December 02, 2013 to February 28, 2014 (during winter time) at two locations, Farmgate and Joydebpur. Conditioned clean filters were loaded to respective filter holder assembly at the CAMS conditioning room and were brought to sampling site in separate clean polyethylene bags at each effective sampling day. After sampling, the filter holder assemblies (keeping the exposed filters inside) were brought to the conditioning room of AECD directly from the sampling site for conditioning and PM retrieval. Care was taken in transporting the exposed filter holder assemblies, so that there should be no PM loss.

2.2 Traffic Volume at the Sampling Site:

A traffic survey was conducted by manual counting of vehicles in the Farm Gate corridor in front of the sampling site and Gazipur Crossing on selected days during the study period to understand correlation between PM concentrations and traffic volume. It was observed that the private cars were the main motorized vehicles (80% of the total vehicles) plying along Farmgate corridor and most of them are of CNG driven. Besides this many old minibus, bus, motor cycle, truck and covered vans were also run through the roadways. It was found that heavy-duty diesel trucks and covered vans operated 17 times more frequently at night than during the day.

At Gazipur, the local roads which are very close to the sampling site, most of the vehicles are of 2-stroke petrol, diesel or shallow engine (Nasimon). It is seen that at day time approximately 2500 numbers of different types of vehicles (mostly diesel driven truck, van, pickup etc) ply per hour through Dhaka-Mymemsing road and 1750 numbers of vehicles (mostly 2-stroke baby taxi, motor cycle, mini-bus and human haler using shallow engine) ply per hour through the station road, which is about 200 m north to the sampling site.

P-ID 93 International Conference on Physics Sustainable Development & Technology (ICPSDT-2015) (August 19-20, 2015) Department of Physics, CUET. Page 143

2.3. Measurement of PM Mass:

PM mass was measured in the Chemistry Lab of the Atomic Energy Centre, Dhaka (AECD). The PM10 and PM2.5 samples were determined by weighing the filters before and after exposure using a microbalance [9]. The filters were equilibrated for 24h at constant humidity of 50% and temperature (22C) in the balance room before each weighing. A Po-210 (alpha emitter) electrostatic charge eliminator was used to eliminate the static charge accumulated on the filters before each weighing. The difference in weights for each filter was calculated and the mass concentrations for each PM10 or PM2.5 samples were determined. The concentrations of PM2.5 and PM10 were determined by reflectance measurement in AECD laboratory using an Evans Electro selenium Limited (EEL) type Smoke Stain Reflectometer [10].

Fig. 1: Teflon Filters, before and after exposure.

2.4. Measurement of SOx and NOx:

This study mainly focused on the concentration of particulate matter, as they influence on climate change and cause adverse health effects. However, SOx and NOx data were collected from CAMS-2 (Farmgate, Dhaka) as well as CAMS-4(Gazipur). Since NOx have only annual standard (BNAAQS) [11], so for this pollutant daily 24- hours average concentration levels were compared with the annual average. During data quality control some data were flagged as invalid and those were not included in the analysis.

P-ID 93 International Conference on Physics Sustainable Development & Technology (ICPSDT-2015) (August 19-20, 2015) Department of Physics, CUET. Page 144

3. RESULTS AND DISCUSSION

PM samplings were performed by using Air Metrics Mini Vol. sampler for collecting both PM2.5 and PM10 samples for three months, December 2013 to February 2014 (i.e. during winter time) at two locations, Farmgate (Dhaka city) and Joydebpur (Gazipur city). PM data was also collected from continuous air monitoring station (CAMS) under Clean Air and Sustainable Environment (CASE) Project of the Department of Environment under Ministry of environment and Forest, Bangladesh.

Concentration of PM2.5 in Dhaka and Gazipur during December 02, 2013 to February16, 2014 are presented in 3 Fig. 2. The highest concentration of PM 2.5 at Dhaka is found 246.5 µg/m on January 03, 2014 and at Gazipur, it 3 3 is 231.5 µg/m on December 12, 2013. The lowest concentration of PM 2.5 at Dhaka is found 40.2µg/m on 3 February16, 2014 and at Gazipur, it is 80.9µg/m on January 10, 2014. In Dhaka, PM2.5 concentration of January, 2014 is higher than that of February, 2014. Similarly in Gazipur, PM2.5 concentration of December, 2013 is higher than that concentration of January, 2014. It is concluded that in the sampling period, the concentration of PM 2.5 at Gazipur is higher than that of Dhaka and the daily average of PM 2.5 for both the cities always exceeds 3 the Bangladesh National Ambient Air Quality Standard (BNAAQS, 65 µg/ m for PM2.5)[11].

Concentration of PM10 in Dhaka and Gazipur during December 02, 2013 to February 25, 2014 are presented in 3 Fig. 3. The highest concentration of PM 10 at Dhaka is found 428.49 µg/m on February 6, 2014 and at Gazipur, 3 3 it is 358µg/m on January 8, 2014. The lowest concentration of PM 10 at Dhaka is found 87.2µg/m on January 3 18, 2014 and at Gazipur, it is 82µg/m on February 16, 2014. In Dhaka, PM10 concentration of December, 2013 is higher than that of January, 2014. It is observed that in the month of December, 2013 the concentration of PM10 in Dhaka is more than that of Gazipur while in the months of January, 2014 and February, 2014 the concentration of PM 10 in Dhaka is less than that of Gazipur. It may happen because there are a large number of brick kilns at a distance of 5-7 km from the Gazipur sampling site. In winter brick kilns goes in operation. It is also seen that almost in the sampling period (December 2013 to February 2014) the concentration of the daily average of PM10 for both the cities do not comply with the required Bangladesh National Ambient Air Quality 3 Standard (BNAAQS,150 µg/m for PM10)[11]

The ratio of PM2.5 and PM10 concentrations gives an idea of on the origin of the particulate pollution in atmospheric air. Fig. 4. shows the ratio of the daily average concentration of PM2.5 and PM10 for Dhaka. The ratio is 0.5. Fig. 5 shows the ratio of the daily average concentration of PM2.5 and PM10 for Gazipur. The ratio is 0.6. Therefore it is concluded that concentration PM10 in the air of Gazipur city is higher than that of Dhaka in winter.

The last 10 years data (CASE, DoE) for concentration of PM 2.5 and PM 10 in the air of Dhaka were compared with our investigations. We have found that our findings are in agreement with CASE data. Therefore, our study reveals that, though the government has taken several steps to minimize air pollution but the concentration of PM 2.5 and PM 10 remains almost same in Dhaka and can never comply the Bangladesh National Ambient Air Quality Standard (BNAAQS).

Fig. 6 and Fig. 7. show the concentration of monthly average of PM2.5 and PM10, respectively, in the air of Dhaka and Gazipur city. The concentration of PM2.5 in the air of Dhaka was found nearly the same in December, 2013 (123.2 µg/m3) and January, 2014 (126.4 µg/m3) and decreases in February, 2014 (83.4 µg/m3). In the air of 3 Gazipur city the concentration of PM2.5 was found maximum in December, 2013 (163.38 µg/m ) and then it decreases in January, 2014 (136.02 µg/m3) and February, 2014 (138.3 µg/m3). In the air of Dhaka city the 3 concentration of PM10 was found maximum in December, 2013 (291.5µg/m ) and then it decreases in January, 2014 (208.72µg/m3) and February, 2014 (178.34µg/m3). Hence we can conclude that, in the eve of the winter (December, 2013) the concentration of PM10 in the air of Gazipur was less than that of Dhaka. But when the brick kilns were operated in full swing (January and February, 2014) the concentration of PM10 was less in the

P-ID 93 International Conference on Physics Sustainable Development & Technology (ICPSDT-2015) (August 19-20, 2015) Department of Physics, CUET. Page 145

air of Gazipur than that of Dhaka. Moreover the variation in vehicle types ply in Dhaka and Gazipur city also contributes in the PM level of these cities. It was observed that the private cars were the main motorized vehicles (80% of the total vehicles) plying along Farmgate corridor and most of them are of CNG driven. But through Joydebpur crossing of Gazipur, approximately 2500 numbers of different types of vehicles ply per hour at day time and most of them are diesel driven truck, van and pickup. Fig. 8 and Fig. 9. show the monthly average concentration of SOx and NOx in the air of Dhaka and Gazipur. It was found that during the sampling period the average value of SO2 in the air of both Dhaka and Gazipur did not exceed the limit value of Bangladesh National Ambient Air Quality Standard (BNAAQS, 140 ppb for SO2). The highest value of SO2 was found 21.8 ppb for Dhaka in the month of February, 2014 and for Gazipur it was 15.4 ppb at the same time. The monthly average value of NOx for the air of Gazipur complied with the Bangladesh National Ambient Air Quality Standard (BNAAQS, 53 ppb for NOx) during the sampling period while NOx concentration at Farmgate, Dhaka found higher than annual average BNAAQS limit values (53 ppb). Here observed 24-hours average was 167ppb and the maximum value was 238 ppb. CAMS-2(Farmgate, Dhaka) is a road side monitoring station and higher traffic congestion may be cause for high NOx concentration.

From this study, it is seen that, the quality of the ambient air of both the Dhaka and Gazipur cities cannot meet the Bangladesh National Ambient Air Quality Standard (BNAAQS) though sampling is performed in a very busy traffic locations at Dhaka (Farmgate) and a residential area of Gazipur (Joydebpur).

P-ID 93 International Conference on Physics Sustainable Development & Technology (ICPSDT-2015) (August 19-20, 2015) Department of Physics, CUET. Page 146

Figures and Tables

Fig. 2: Concentration of PM 2.5 in Dhaka and Gazipur (During Dec. 2013-Feb. 2014)

Fig. 3: Concentration of PM10 in Dhaka and Gazipur (During Dec. 2013- Feb. 2014)

Fig. 4: Concentration of PM2.5 /PM10 in Dhaka (During Dec. 2013-Feb. 2014)

P-ID 93 International Conference on Physics Sustainable Development & Technology (ICPSDT-2015) (August 19-20, 2015) Department of Physics, CUET. Page 147

Fig. 5: Concentration of PM2.5 /PM10 in Gazipur (During Dec. 2013-Feb. 2014)

Fig. 6: Concentration of Monthly average of PM2.5 in Dhaka and Gazipur

(* Data was collected from CAMS-4,Gazipur)

Fig. 7: Concentration of Monthly average of PM10 in Dhaka and Gazipur

P-ID 93 International Conference on Physics Sustainable Development & Technology (ICPSDT-2015) (August 19-20, 2015) Department of Physics, CUET. Page 148

Fig. 8: Monthly average concentrations (ppb) of NOx in the air of Dhaka and Gazipur

Fig. 9: Monthly average concentrations (ppb) of NOx in the air of Dhaka and Gazipur

Table-1. Concentrations of SOx and NOx in the air of Dhaka and Gazipur.

SO2(ppb) NOx(ppb) Dhaka Gazipur Dhaka Gazipur Average 7.76 2.4 191 45.9 December,2013 Maximum 13.3 3.63 273 98.6 Minimum 3.82 1.57 87.5 18 Average 9.72 4.26 150 33.6 January,2014 Maximum 20.3 7.13 224 77 Minimum 4.56 2.83 81.5 7.35 Average 12.1 7.82 166.65 50.5 February,2014 Maximum 21.8 15.4 238.15 139.46 Minimum 6.75 3.11 98.6 14.5 * Source: CAMS-2, Farmgate,Dhaka and CAMS-4, Gazipur.

P-ID 93 International Conference on Physics Sustainable Development & Technology (ICPSDT-2015) (August 19-20, 2015) Department of Physics, CUET. Page 149

4. CONCLUSION

The Particulate matter concentration of PM2.5 and PM10 in the air of Dhaka and Gazipur city during winter period has been compared. It was found that the concentration of PM2.5 and PM10 in air of Dhaka remains almost constant for the last 10 years. The concentration of PM2.5 and PM10 in Gazipur is higher than that of Dhaka in winter period. Brick kiln emission and long range transports are the particulate matter sources those increase the particulate matter in Gazipur compared to Dhaka. Although the government has taken several steps including introducing CNG driven vehicles but there are no effective change in PM concentration. So initiatives have to be taken to control the PM emission from brick kilns, which will give positive impact on the air quality of these cities.

ACKNOWLEDGEMENTS

The authors thankfully acknowledge the Chemistry Division of Atomic Energy Centre, Dhaka for providing lab facilities and the CASE Project of the Department of Environment to give permission for sampling at CAMS-2 and CAMS-4 sites.

REFERENCES

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P-ID 93 International Conference on Physics Sustainable Development & Technology (ICPSDT-2015) (August 19-20, 2015) Department of Physics, CUET.