Air Quality Trends in Colombo

AIR QUALITY TRENDS IN THE CITY OF COLOMBO

R.N.R.Jayaratne Prof. O.A.Ileperuma Senior Environmental Officer Senior Lecturer Central Environmental Authority University of Peradeniya

1 National Stakeholders Forum – Sri Lanka – 12th June 2007  Two continuous Ambient Air Quality Monitoring Stations were set up in December 1996 at Colombo Municipal Council area under World Bank Funded project called CUTP.

- to monitor major air pollutants (NO,NO2,NOX, SO2, O3,CO & PM10) - with meteorological parameters (WS,WD,VWS, SR,RF,ATE)

One of these monitoring station is located at Colombo Fort Railway station premises and other one was located at Meteorological Department premises. Met Department one was operated from 1997 to 2000.

Colombo Fort one has been in operation since 1997 2

National Stakeholders Forum – Sri Lanka – 12th June 2007 Location of the Colombo Fort Monitoring Station

Barge Mountained Power Plant (Thermal)

Kelanitissa Power Station (Thermal)

Ambient Air Quality Monitoring station (Colombo Fort)

National Stakeholders Forum – Sri Lanka – 12th June 2007 Locations of Two Ambient Air Quality Monitoring Stations Kelanithissa Power Plant

Barge Mountained Power Plant

Ambient Air Quality Monitoring Station 1 (Colombo Fort Railway Stn)

Ambient Air Quality Monitoring Station 2 (Meteorological Dpt)

4 Colombo Fort Ambient Air Quality Monitoring Station Inside of the monitoring station

National Stakeholders Forum – Sri Lanka – 12th June 2007 Monitoring Principles

Ozone UV Absorption

Carbon Monoxide Non Dispersive Infra Red (NDIR) Nitrogen Oxides Chemiluminescence

Sulfur Dioxide UV Fluorescence

PM10 High Volume Sampling

National Stakeholders Forum – Sri Lanka – 12th June 2007 • Five minute and one hour average concentrations of measured parameters were recorded in data logger.

• Every day at midnight an automatic calibration cycle is carried out to check the accuracy and validity of data.

• All valid data collected from these two monitoring stations from January 1997 to Dec 2006 were used for this analysis.

National Stakeholders Forum – Sri Lanka – 12th June 2007 • To identify the trend and variations of major air pollutants for the city of Colombo during the monitoring period.

(This report will also help to identify gaps in the available information and data requirements for long term monitoring.)

National Stakeholders Forum – Sri Lanka – 12th June 2007 Methodology • Converted all recorded data in binary form in the data logger into digital form by using WINCOLLECT software . • Screened the data base to select good data (Validation) based on daily calibration and instrument errors. • All valid data are presented by diagrams, graphs and tables to identify features and variation patterns easily. • Interpretations are made in scientific manner with recommendations.

National Stakeholders Forum – Sri Lanka – 12th June 2007 Trends on air pollutants in Colombo

Trend graphs of nitrogen dioxide, sulfur dioxide, carbon monoxide, ozone for both monitoring stations are presented in graphical form and the statistical parameters represented as in the following format.

Maximum concentration

75th percentile

Arithmetic mean of data values

25th percentile

Minimum concentration

National Stakeholders Forum – Sri Lanka – 12th June 2007 Variation of Nitrogen Dioxide (NO2) One Hour Average Concentrations at Colombo Fort Ambient Air Quality monitoring station(1997-2001)

National standard 0.13 ppm

0.12

Trend line (Average)

0.08

Concentration (ppm) Concentration

2 0.04

0.00

Jul-97 Jul-98 Jul-99 Jul-00 Jul-01

Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Month

National Stakeholders Forum – Sri Lanka – 12th June 2007 Variation of Sulfur Dioxide (SO2) One Hour Averages concentrations at Colombo Fort Ambient Air Quality monitoring station

0.32 (ppm)

0.16

National standard 0.08 ppm

2 SO

SO2 Concentration (PPM) Concentration SO2

0.00

Jul-97 Jul-98 Jul-99 Jul-00 Jul-01

Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Month 12

National Stakeholders Forum – Sri Lanka – 12th June 2007 Variation of Carbon Monoxide (CO) One Hour Average Concentrations at Colombo Fort Ambient Air Quality monitoring station (1997-2001)

3.8

2.5

1.3

CO Concentration (ppm) Concentration CO

0.0

Jul-97 Jul-98 Jul-99 Jul-00 Jul-01

Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Month 13

National Stakeholders Forum – Sri Lanka – 12th June 2007 Variation of ozone (O3) One Hour Average Concentrations at Colombo Fort Ambient Air Quality monitoring station(1997-2001) 0.4

0.2 Concentration (ppm) Concentration

3 National standard 0.1 ppm

O3 Concentrationse (ppm) Concentrationse O3 O

0.0

Jul-97 Jul-98 Jul-99 Jul-00 Jul-01

Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Month 14

National Stakeholders Forum – Sri Lanka – 12th June 2007 Variation of monthly one hour averages of Nitrogen Dioxide (NO2)concentrations at Colombo Meteorological Department Air Quality monitoring station (From Jan 1997 to December 2000)

National Standard 0.13 ppm 0.12

0.08

Concentration (ppm) 0.04

0.00

Jul-97 Jul-98 Jul-99 Jul-00

Jan-97 Sep-97 Jan-98 Sep-98 Jan-99 Sep-99 Jan-00 Sep-00

Nov-97 Nov-98 Nov-99 Nov-00

Mar-97 Mar-98 Mar-99 Mar-00

May-97 May-98 May-99 May-00 Month 15

National Stakeholders Forum – Sri Lanka – 12th June 2007 Variation of monthly one hour averages of Sulfur Dioxide (SO2) concentrations at Colombo Meteorological Department Air Quality monitoring station (From Jan 1997 to December 2000) 0.10

0.08

0.06

0.04

Concentration (ppm) Concentration

0.02

0.00

Jan-97 Jan-98 Jan-99 Jan-00

Sep-97 Sep-98 Sep-99 Sep-00

May-97 May-98 May-99 May-00 Month 16

National Stakeholders Forum – Sri Lanka – 12th June 2007 Variation of monthly one hour averages of Carbon monoxide (CO) concentrations at Colombo Meteorological Department Air Quality monitoring station (From Jan 1997 to December 2000)

Concentration (ppm) Concentration

Jan-97 Jan-98 Jan-99 Jan-00

Sep-97 Sep-98 Sep-99 Sep-00

May-97 May-98 May-99 May-00 Month 17

National Stakeholders Forum – Sri Lanka – 12th June 2007 Variation of monthly one hour averages of ozone (O3) concentrations at Colombo Meteorological Department Air Quality monitoring station (From Jan 1997 to December 2000)

National Stakeholders Forum – Sri Lanka – 12th June 2007 Nitrogen Dioxide Concentration Monthly Mean and Maximum of one hour averages at Colombo Fort ( June 2003 - December 2006) 0.14

National Ambient Air Quality Strandard for NO 2 for one hour average = 0.013 ppm 0.12 NO2 Mean NO2 Maximum 0.10 Linear (NO2 Mean)

0.08

0.06

0.04

Concentrations (ppm) Concentrations

0.02 y = 0.0001x + 0.0143

0.00

Jul Jul Jul

Oct Oct Oct

Apr Apr Apr

Jun Jan Jun Jan Jun Jan Jun

Nov Dec Feb Mar Nov Dec Feb Mar Nov Dec Feb Mar

Aug Sep Aug Sep Aug Sep

May May May July

August

October

November December

September 2003 2004 2005 2006 Month and Year

National Stakeholders Forum – Sri Lanka – 12th June 2007 Sulphur Dioxide Concentration Monthly Mean and Maximum of 1 hour averages at Colombo Fort ( June 2003 - December 2006 ) 0.16 SO2 Mean 0.14 SO2 Maximum Linear (SO2 Mean) 0.12

0.10

0.08 National Ambient Air Quality Strandard for SO2 for one hour average =0 .08 ppm

0.06

Concentration (ppm) Concentration 0.04

0.02 y = 2E-05x + 0.0068 0.00

Jul Jul Jul

Oct Oct Oct

Apr Apr Apr

Jun Jan Jun Jan Jun Jan Jun

Nov Dec Feb Mar Nov Dec Feb Mar Nov Dec Feb Mar

Aug Sep Aug Sep Aug Sep

May May May July

August

October

November December

September 2003 2004 2005 2006 Month and Year

20 Carbon Monoxide Concentration Monthly Mean and Maximum of 1 hour averages at Colombo Fort ( June 2003 - December 2006 ) 9 CO Average 8 CO Maximum 7 Linear (CO Average)

Concentration (ppm) Concentration 2 y = -0.0217x + 1.0988 1

Jul Jul Jul

Oct Oct Oct

Apr Apr Apr

Jun Jan Jun Jan Jun Jan Jun

Nov Dec Feb Mar Nov Dec Feb Mar Nov Dec Feb Mar

Aug Sep Aug Sep Aug Sep

May May May July

August

October

November December

September 2003 2004 2005 2006 Month and Year National Ambient Air Quality Strandard for 24 hour average = 26 ppm

21 Variation of 24 hour averages of PM10 concentrations at Colombo Fort Air Quality monitoring station (From Jan 1997 to December 2001)

22 Variation of 24 hour averages of PM10 concentrations at Colombo Meteorological Department Air Quality monitoring station (From Jan 1997 to December 2000) 160 USEPA Standard Value 150µgm-3

140

120

)

-3 100

Concentrationμgm (

1-Jul-00 8-Jul-00

3-Jun-00

7-Oct-00

2-Sep-00 9-Sep-00

15-Jul-00 22-Jul-00 29-Jul-00

5-Aug-00

10-Jun-00 17-Jun-00 24-Jun-00

14-Oct-00 21-Oct-00 28-Oct-00

16-Sep-00 23-Sep-00 30-Sep-00

12-Aug-00 19-Aug-00 26-Aug-00 13-May-00 20-May-00 27-May-00 23 Date Variation of monthly one hour averages of PM10 concentrations at Colombo Fort Air Quality monitoring station (From Jan 2002 to June 2004)

160 Standard Value 150 µg/m-3

Trend line 120

Concentration Concentration (µg/m-3)

Jul-02 Jul-03

Oct-02 Oct-03

Apr-02 Apr-03 Apr-04

Jan-02 Jan-03 Jan-04 Date 24 Variation of PM-10 concentrations (24 hour average) at Colombo Fort monitoring site (from 1998 to 2005)

160

120

-3

y = -0.0109x + 79.292 80

Concentration µgm Concentration 40

2-Jul-98 4-Jul-02 1-Jul-03

3-Oct-05

5-Jan-03 2-Jan-04

9-Jun-99 4-Nov-00 4-Dec-01 7-Nov-03 1-Jun-04 5-Nov-04 2-Feb-05

1-Mar-99 7-Sep-03

23-Jul-04

30-Jan-00 22-Jan-04

22-Nov-98 19-Nov-99 15-Apr-00 20-Jun-00 12-Feb-01 12-Feb-02 25-Feb-04 13-Apr-04 30-Apr-04 20-Jun-04 28-Nov-04 29-Jun-05

15-Sep-98 12-Sep-04 13-Mar-04 27-Sep-04 25-Mar-05

31-Aug-99 28-Aug-00 10-Aug-04 12-May-05 16-Aug-05 1998 1999 2000 2002 2003 2004 2005 Date and year

Series124 hour average TrendLinear line (Series1) 25 Annual averages of PM-10 at Colombo

Fort Monitoring site (1998-2006)

- g/m  100 Standard - 50 μgm-3 75

µg/m3 25

Annual Average concentration Average Annual 10

1998 1999 2000 2001 2002 2003 2004 2005 2006 PM Year

26 Increasing trends of NO2,SO2 & PM10  Increasing amount of air pollutants with increasing number of vehicles and the capacity of thermal power generation utilizing fossil fuels were the major reasons for these increasing trends.

Increasing number of brand new passenger transport vehicles instead of re-conditioned vehicles the major reasons for these slight increasing trends Decreasing trend of CO

 Improvements of internal combustion engines to reduce emission, gradually decreasing of petrol driven vehicles in the vicinity of monitoring station are the major reasons and another possible reason was reaching more ultraviolet radiation into the lower atmosphere stimulating of producing hydroxyl free radicals for decline of carbon monoxide

27 Comparisons of the variations of air quality monitoring data between Colombo Fort and Meteorological department sites

4000

10000 3000

2000 5000

Frequency

1000 National standard 0.08 ppm 0.08 standard National

National standard 0.13 ppm 0.13 standard National 0 0 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 SO2 NO2 SO2 Concentration (One hour average) in ppm NO2 Concentration (One hour average) in ppm Frequency distribution of SO2 one hour average Frequency distribution of NO2 one hour average concentrations at Colombo Fort (1997-2004) concentrations at Colombo Fort (1997-2004)

5000 2000 4000

3000

1000 2000

Frequency

1000 National standard 0.08 ppm 0.08 standard National 0 ppm 0.13 standard National 0

0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 NO2 SO2 NO2 Concentration (One hour average) in ppm SO2 Concentration (One hour average) in ppm

Frequency distribution of NO2 one hour average Frequency distribution of SO2 one hour average28 concentrations at Meteorological department (1997-2000) concentrations at Meteorological department (1997-2000) Comparisons of the variations of air quality monitoring data between Colombo Fort and Meteorological department sites Cont……

7000 7000

6000 6000

5000 5000 National standard 0.1 ppm 4000 4000

3000 3000

Frequency

Frequency 2000 2000

1000 1000

0 0

0.0 1.2 2.4 3.6 4.8 6.0 0.0 0.1 0.2 0.3 0.4 CO O3 CO Concentration (One hour average) in ppm O3 Concentration (One hour average) in ppm

Frequency distribution of CO one hour average Frequency distribution of O3 one hour average concentrations at Colombo Fort (1997-2004) concentrations at Colombo Fort (1997-2004)

3000 5000

4000 2000 3000 National standard 0.1 ppm

2000

Frequency 1000 Frequency

1000

0 0

0.0 1.2 2.4 3.6 4.8 6.0 0.0 0.1 0.2 0.3 0.4 CO O3 CO Concentration (One hour average) in ppm O3 Concentration (One hour average) in ppm

Frequency distribution of CO one hour average Frequency distribution of O3 one hour average29 concentrations at Meteorological department (1997-2000) concentrations at Meteorological department (1997-2000) Comparisons of the variations of air quality monitoring data between Colombo Fort and Meteorological department sites Cont……

USEPA standard 150 μgm-3 30

Frequency

10 60 110 160 Concentration (ug/m3) PM10 Concentration (One hour average) in ppm

Frequency distribution of PM10 24 hour average concentrations at Colombo Fort (1997-2004) 20

Frequency

10 60 110 160

PM10 ConcentrationConcentration (One hour (mg/m3) average) in ppm

Frequency distribution of PM10 24 hour average concentrations at Meteorological department (1997-2000)30 The area between 2000-2900 from Meteorological Department site. (High ozone concentration recorded when wind came from this area).

Meteorological Department monitoring station

Variation of O3 concentrations with wind direction At Meteorological Department site

2000-2900

Galle Road

31 High Level Road NO2 emission from vehicles in Colombo Metropolitan Area (g/km)

2500

2000

-1

1500

(X1000)gkm

1000

Emmision of NO 500

Petrol Petrol Petrol Petrol Petrol Petrol Petrol Petrol Petrol Petrol Petrol Petrol Petrol

Diesel Diesel Diesel Diesel Diesel Diesel Diesel Diesel Diesel Diesel Diesel Diesel Diesel 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Year and fuel type

Motor cars Motor trycicles Motor Cycles Buses Duel purpous Lorries Others

NO2 emission of diesel three-wheelers are not included because Difficulty to find NO2 emission factor of diesel three-wheelers The number of diesel three-wheelers are very few compared to other vehicle groups 32 60% of total number of vehicles registered in Sri Lanka are assumed to be in Colombo Metropolitan Area based on the study done by transport studies and planning center under CUTP in 1996 SO2 emission from vehicles in Colombo Metropolitan Area (g/km)

800

-1

600

(X1000) gkm (X1000)

400

Emmision of SO

200

Petrol Petrol Petrol Petrol Petrol Petrol Petrol Petrol Petrol Petrol Petrol Petrol Petrol

Diesel Diesel Diesel Diesel Diesel Diesel Diesel Diesel Diesel Diesel Diesel Diesel Diesel 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Year and Fuel type

Motor cars Motor trycicles Motor Cycles Buses Duel purpous Lorries Others

SO2 emission of diesel three-wheelers are not included because Difficulty to find SO2 emission factor of diesel three-wheelers The number of diesel three-wheelers are very few compared to other vehicle groups 33 60% of total number of vehicles registered in Sri Lanka are assumed to be in Colombo Metropolitan Area based on the study done by transport studies and planning center under CUTP in 1996 Fuel consumption and amounts of NO2 and SO2 emissions relevant to the power sector in Sri-Lanka

600 16

450 12

(X10

& NO & 300 8 2

Emission Emission of SO

Fuel Usage for Fuel Electricity(X1000)MTUsage 150 4

0 0 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Year

SO2 NO2 Auto Diesel Furnace Oil Naphtha 34 Electricity generation of Sri-Lanka

Hydro Thermal Self Genaration Wind Total Generation 8000

6000

4000

Electricity Generation (GWh) Electricity

2000

0 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Year 35 Variation of rainfall in four seasons during the year in Colombo

Northeast monsoon (December- First intermonsoon February) (March-April) 13% 15%

Second intermonsoon (October - November) Southwest monsoon 28% (May - September) 44%

Rainfall data- Report on Climate by M.B.G.de Silva based on rainfall data from 1961-1990 in Arjun’s Atlas of Sri Lanka 36 Central Environmental Authority 12/1/1998 to 2/27/1999

WindStation: Fort pattern of four monsoonal seasons during the year at Colombo Fort monitoring station

0 N 338 30% 22

315 45 North-East monsoon 20% (December – February)

292 10% 68

0% 270 90 Dfgggfsgga Central Environmental Authority 3/1/1999 to 3/30/1999 > 8

6 to 8 Station: Fort 248 112 4 to 6

2 to 4

225 135 0 1 to 2 N 338 30% 22 0 to 1 202 158 180 315 45 20% Magnitude() -1 Magnitude(ms0.0% calm ) Rainfall 13% 94.4% Valid Data present. 292 10% 68

270 90

> 8

6 to 8 248 112 First inter-monsoon 4 to 6 (March – April) 2 to 4 225 135 1 to 2

0 to 1 202 158 180 Magnitude(msMagnitude() -1) Rainfall 15%37 0.0% calm 81.7% Valid Data present. Central Environmental Authority 5/1/1999 to 9/29/1999

WindStation: Fort pattern of four monsoonal seasons during the year at Colombo Fort monitoring station

0 N 338 40% 22

315 30% 45 South-west monsoon

20% (May to September )

292 68 10%

0% 270 90 Go Central Environmental Authority 10/1/1999 to 11/29/1999 > 8

6 to 8 Station: Fort 248 112 4 to 6

2 to 4

225 135 1 to 2 0 N 338 30% 22 0 to 1 202 158 180 315 45 20% Magnitude() Rainfall 44% -1 Magnitude(ms0.0% calm ) 97.8% Valid Data present. 292 10% 68

270 90

> 8

6 to 8 Second inter-monsoon 248 112 (October to November) 4 to 6 2 to 4

225 135 1 to 2

0 to 1 202 158 180 Magnitude() 38 Magnitude(ms-1) Rainfall 28% 0.0% calm 89.1% Valid Data present. Variation of air pollutant concentrations with time and date

The statistical parameters calculated with respect to the time and date were presented in graphical form to study the variation patterns during the day and the week. The statistical parameters of air pollutants are represented in these graphs in following format.

75th Percentile

Average

25th Percentile

39 0.04 0.03 0.03 Variation of one hour averages of NO concentrations with time 0.02 2 at Colombo Fort monitoring 0.02 station 0.01

Concentration(ppm) 0.01 0.00

0:00 2:00 4:00 6:00 8:00

10:00 12:00 14:00 16:00 18:00 20:00 22:00 TIME

0.04 0.03 0.03 0.02 0.02 0.01 Variation of one hour averages of 0.01

Concentration (ppm) Concentration SO2 concentrations with time at 0.00 Colombo Fort monitoring station

0:00 2:00 4:00 6:00 8:00

10:00 12:00 14:00 16:00 18:00 20:00 22:00 TIME 40 1.20 1.00 0.80

0.60 Variation of one hour averages of 0.40 CO concentrations with time at Colombo Fort monitoring station 0.20

Concentration (ppm) Concentration 0.00

0:00 2:00 4:00 6:00 8:00

10:00 12:00 14:00 16:00 18:00 20:00 22:00 TIME

0.008

0.006

0.004

0.002

Variation of one hour averages of (ppm) Concentration 0 O3 concentrations with time at Colombo Fort monitoring station

0:00 2:00 4:00 6:00 8:00

10:00 12:00 14:00 16:00 18:00 20:00 22:00 TIME 41 0.02

0.01

Variation of one hour averages of 0.00 NO2 concentrations with time at

Concentration (ppm) Concentration Colombo Meteorological 0.00 Department monitoring station

0:00 2:00 4:00 6:00 8:00

10:00 12:00 14:00 16:00 18:00 20:00 22:00 TIME

0.02

0.01

0.01 Variation of one hour averages of SO concentrations with time at 2 (ppm) Concentration Colombo Meteorological Department monitoring station 0.00

0:00 2:00 4:00 6:00 8:00

10:00 12:00 14:00 16:00 18:00 20:00 22:00 TIME 42 1.2 1.0

0.8 0.6

0.4 Variation of one hour averages of CO concentrations with time at 0.2 Concentration (ppm) Concentration Colombo Meteorological 0.0 Department monitoring station

0:00 2:00 4:00 6:00 8:00

10:00 12:00 14:00 16:00 18:00 20:00 22:00 TIME

0.05

0.04

0.03

0.02

Variation of one hour averages 0.01 of O3 concentrations with time (ppm) Concentration at Colombo Meteorological 0.00 Department monitoring station

0:00 2:00 4:00 6:00 8:00

10:00 12:00 14:00 16:00 18:00 20:00 22:00 TIME 43 Variation of air pollutant concentrations with date

0.030

0.025

0.020

0.015

0.010 Variation of one hour averages of 0.005 NO2 concentrations with day at Concentration (ppm) Concentration Colombo Fort monitoring station 0.000 Sun Mon Tue Wed Thu Fri Sat Day

0.025

0.020

0.015

0.010

Variation of one hour averages of 0.005

Concentration (ppm) Concentration SO2 concentrations with day at Colombo Fort monitoring station 0.000 Sun Mon Tue Wed Thu Fri Sat 44 Day 0.02

0.01

0.01 Variation of one hour averages

of NO2 concentrations with day Concentration (ppm) Concentration at Colombo Meteorological Department monitoring station 0.00 Sun Mon Tue Wed Thu Fri Sat Day

0.006

0.003

Variation of one hour averages of

Concentration (ppm) Concentration

SO2 concentrations with day at Colombo Meteorological 0.000 Department monitoring station Sun Mon Tue Wed Thu Fri Sat 45 Day 0.8 0.7 0.6 0.5 0.4 0.3 0.2 Variation of one hour averages

Concentration (ppm) Concentration of CO concentrations with day at 0.1 Colombo Fort monitoring 0 station Sun Mon Tue Wed Thu Fri Sat Day

100

Concentration ( gm-3) Concentration Variation of 24 hour averages of

PM10 concentrations with day at 50 Colombo Fort monitoring station Sun Mon Tue Wed Thu Fri Sat Day 46 CONCLUSIONS

Air pollution trends with respect to sulfur dioxide and nitrogen dioxide are slowly increasing while carbon monoxide is slowly decreasing.

Increasing amount of air pollutants with increasing number of vehicles and the capacity of thermal power generation utilizing fossil fuels were the major reasons for these increasing trends.

Improvements of internal combustion engines to reduce emission, gradually decreasing of petrol driven vehicles in the vicinity of monitoring station are the major reasons and another possible reason was reaching more ultraviolet radiation into the lower atmosphere stimulating of producing hydroxyl free radicals for decline of carbon monoxide

The trend with respect to PM10 is slowly increasing over the period from Jan 1998 to June 2003. However , reaseantly we observed slight decreasing of PM-10 47 CONCLUSIONS Cont…….

Emissions from increasing fleet of vehicles are the major contributor of air pollution in Colombo City.

The emissions from thermal power stations operating in and near the Colombo metropolitan area using relatively high sulfur fuel are added burden for air pollution in Colombo City.

Prevailing wind pattern and rainfall pattern with monsoons are the major factors for seasonal variation pattern of air pollutants concentrations.

PM10 concentration in Colombo city with presence of sulfur dioxide is the serious cause to concern.

48 49 References

1 Howard S.Peavy,Donald R. Rowe and George Tchobanoglous, (International Ed), Environmental Engineering, McGraw-Hill, Singapore(1985) p.1-8 & 418-463

2 Bernard J Nebel & Richard T Wright,(7th Ed),Environmental Science The way the world works, Prentice Hall, Upper saddle River, New Jersy.(p 524-549)

3 PGIS, University of Peradeniya, Workshop on Acid Rain Monitoring & Air Quality Monitoring and Management Proceedings,(2001).p1-5 4 Arudpragasam K.D. (Editor in chief), Man And Environment, An introduction to Environmental Studies, Central Environmental Authority , Colombo 10, (1999), p129- 164 5 UEPA,APTI, Air Pollution Control Orientation Course Self-Instructional Manual, Air Pollution Training Institute(APTI),Environmental Research Center , NC 27711,USA (1992) 6 Lakdasa Wijethilake and Suhashini A.R.Karunaratne, Air Quality Management Considerations for Developing countries, World Bank Technical Paper Number 278,The World Bank, Washington D.C.(1995) 7 UNEP,Urbun air pollution,GEMS Environmental library NO-04,UNEP, Niroby, Kenya (1998) 8 World Health Organization, Guidelines For Air Quality,World Health Organization, Geneva (2000)

9 Jiry Hanzak, Jaroslay Pekarec, Volatile Organic Compounds in the Atmosphere at50 the background level, Report on case study, Czech hydro meteorological institute, Kosetice observatory, Czech Republic NoExceedences of Exceedences- SO2 One of Hour one Average-Fort hour Railway averages Station Site SO2 from national standard at 1997-2001 Colombo Fort Monitoring site (1997-2001)

50 40 30 Number of exceedences of one hour average 20 concentration of SO2 10

No of Exceedencesof No 0

Jul-97 Jul-98 Jul-99 Jul-00 Jul-01

Jan-97 Jan-98 Jan-99 Jan-00 Jan-01

Oct-97 Oct-98 Oct-99 Oct-00 Oct-01

Apr-97 Apr-98 Apr-99 Apr-00 Apr-01 Month

1-hourly SO2 Exceedences vs Wind Direction

0.350

0.300 Variation of SO2 0.250 exceedences with

wind direction 0.200

0.150

0.100

Concentration (ppm) Concentration

0.050

0.000 0 30 60 90 120 150 180 210 240 270 300 51330 360 Wind Direction Variation of NO2 concentrations with rain fall

Variation of SO2 concentrations with rain fall 52 Variation of CO concentrations with rain fall

Variation of O3 concentrations with rain fall

53 Variation of NO2 concentrations with wind direction

Variation of SO2 concentrations with wind direction

54 Variation of CO concentrations with wind direction

Variation of O3 concentrations with wind direction

55 Variation of NO2 concentrations with wind speed

Variation of SO2 concentrations with wind speed

56 Variation of CO concentrations with wind speed

Variation of O3 concentrations with wind speed

57 This report will provide trend information on air quality

• To assist in the development of appropriate reporting methodology

• To create systems tackling progress in air quality management

• To provide guidance and direction for policy makers, decision makers, planners and policy analysts in the private and government sectors. 58 Percentage Percentage Total No Air Mean Median Min Max of data of missing of data pollutant ppm ppm ppm ppm captured data points

NO2 70.3% 29.7% 46161 0.019 0.017 0.00 0.121

SO2 69.9% 30.1% 45924 0.013 0.008 0.00 0.331

CO 63.7% 36.3% 41838 0.546 0.382 0.00 9.515

Colombo Colombo Fort monitoring monitoring Station O3 28.1% 71.9% 15172 0.005 0.003 0.00 0.378

NO2 38.6% 61.4% 13282 0.008 0.007 0.00 0.047

SO2 43.8% 56.2% 15090 0.004 0.003 0.00 0.043

CO 40.7% 59.3% 14042 0.435 0.310 0.00 5.060

monitoring monitoring station O 39.7% 60.3% 13667 0.021 0.011 0.00 0.364

3 59 Meteorological Meteorological Department Summary of monitoring data for PM10

Total No Mean Median Min Max of data μgm-3 μgm-3 μgm-3 μgm-3 points

Colombo Fort monitoring station * 424 76.8 74 35 153

Colombo Meteorological 193 52.3 50 13 111 Department monitoring station **

• PM 10 sampling was carried out once in four days from May 1997 to December 2001 and once in three days from May 2003 to June 2004.

** PM 10 sampling was carried out once in four days from May 1997 to December 2000.