IJREES Vol17 P2 June20 Antai

POLLUTANT STANDARD INDEX AND AIR QUALITY INDEX OF THE DRY SEASON CRITERIA AIR POLLUTANTS OF PORT HARCOURT AND ITS ENVIRONS, NIGER DELTA, NIGERIA

Antai, Raphael E.1; Osuji, Leo C. 2; Obafemi, Andrew A.3 and Onojake, Mudiaga C.4 1 Institute of Natural Resources, Environment and Sustainable Development, University of Port Harcourt, Nigeria. 1 Inter - Environments Limited, Rumudara, Port Harcourt, Nigeria. 2,4 Department of Pure and Industrial Chemistry, University of Port Harcourt, Nigeria. 3 Department of Geography and Environmental Management, University of Port Harcourt, Nigeria. Corresponding Author: [email protected]

ABSTRACT

Pollutant standards indices (PSI) were computed for each study area to indicate the concentration level of each pollutant in the study area, while air quality indices were computed to show the degree of air pollution effects on human health in Port Harcourt and its environs. The Air Quality index (AQI) revealed the health effects on people in the respective study area may be experienced. Results of AQI indicated that Eleme, Obio/Akpor and Port Harcourt are most polluted areas compared to Oyigbo, Ikwerre Local Government Area (LGA) and Etche in the dry season.

Keywords: Pollutant Standard Index, Air Quality Index, Dry Season, Criteria Air Pollutants.

1. INTRODUCTION

Generally, the study revealed that Eleme, Obio/Akpor and Port Harcourt areas are exposed to high pollutants concentrations, especially sulphur dioxide, methane, nitrogen dioxide and particulate matter, which may adversely affect public health or aggravate the health conditions of the exposed population (Chelana, et al., 2002; Longhurst, 2005; Efe, 2006; and Antai et al., 2016). Potential health issues likely to prevail in these areas may include asphyxiation, narcosis (that is depression of the central nervous system), cardiac arrest and aspiration. Cases of chronic bronchitis, pulmonary emphysema, and cancer of the bronchus mucous membrane caused by air pollutants may be prevalent in these areas. Prolonged exposure to these pollutants may result in increased cases of Asthma, and respiratory diseases. Long-term health effects due to continuous daily exposure of the general public are therefore envisaged. This study was designed specifically to assess air quality of Port Harcourt and its environs and develop its air quality index model in the dry season (US EPA 2006). This study has created Port Harcourt and its environs air quality index foundation for future reference of the study area.

Port Harcourt metropolis is located between latitudes 4035’ and 5030’ north and between longitudes 6054’ and 7008’ east. It covers an estimated area of 1811.6 square kilometers and is the capital of Rivers State. Port Harcourt was established in 1914 by the British colonial administration under Lord Lugard to meet the pressing economic needs of Europe. The metropolis lies at the heart of the Niger Delta, which is one of the world’s richest wetlands, and is bounded on the south by the Atlantic Ocean, to the north by Imo and Abia States to the east by Akwa Ibom State and to the west by Bayelsa and Delta States. Some of the well-known residential areas in Port Harcourt and its environs include: Port Harcourt Town, Obio/Akpor, Eleme, Oyigbo, Ikwerre and Etche Local Government Areas (Overview of Rivers State - Niger Delta Budget Monitoring Group, 2005).The main city of Port Harcourt lies within the Port Harcourt Local Government Area. The city consists of the former European quarters, now called Old Government Reservation Area (GRA) and new layout areas. Port Harcourt, which is ranked as the fifth largest city in Nigeria, is made up of the city itself, Obio/Akpor Local Government Area and part of Eleme Local Government Area. It has the second largest sea port in Nigeria. The metropolis is the hub of industrial, oil and gas, commercial, administrative and other activities in Rivers State. The city is often referred to as the Treasure Base of the Nation.

2. MATERIALS AND METHODS

Sample and Sampling Techniques The study primarily includes selection of sampling sites, field assessment/measurement, data reading, data storage, statistical data analysis, data interpretation and report writing. Hand-held in-situ portable meters were used and

application of standard ambient air quality assessment procedures were strictly adhered to. Field data measurement was done in-situ with the calibrated portable meters in accordance with the recommended standard procedures for environmental data collection in Nigeria FEPA, (1991), FMEnv, (2002), DPR, (2002) and WHO (2005) procedures for population density, topography, industrial cluster, and heavy traffic for site selection studies. The field data assessment of the air quality and meteorological parameters were sampled on hourly basis, three hours per sampling point (morning, afternoon and evening as peak, off peak and peak periods, respectively) for 17 days in the dry season. Series of different sensors of the in-situ portable meters were used for different air quality pollutants sampling with height of about two meters in the prevailing wind direction and a short exposure limit of three minutes per each air pollutant reading. The air pollutants were logged in and the readings were recorded at stability.

Pollutant Standards Index (PSI) and Air Quality Index (AQI) A type of air quality index known as Pollutant Standards Index was used to determine the level of pollutants in air. This was computed using the following equation and air quality index table (equation 1).

I i, j1  I i, j I i  X i  X i, j  I i, j X i, j1  X i, j (1)

for Xi,j X i X i, j1 th Where Xi = Observed concentration for the i pollutant th th Iij = PSI value for the i pollutant and the j breakpoint as given in the table th th Iij+1 = PSI value for the i pollutant and the (j+1) breakpoint as given in the table th th Xij = Concentration for the i pollutant and j breakpoint as given in the table th th Xij+1 = Concentration for the i pollutant and (j+1) breakpoint as given in the table Concentrations of pollutants were expressed in terms of low, moderate, high and critical based on the computed values of EF and PSI (CPCB, 2006).

Figure 1: Port Harcourt and its Environs showing Sampling Points for the Study

Table 1: Sampling Points Key, Description of Sampling Points, Coordinates and Frequency of Monitoring. Sampling Description of Sampling Points Coordinates Frequency of Monitoring/Hourly Point Code: SP 1 Onne Roundabout by FLT and FOT Signboard N 040 43’. 207’’ E 0070 09’. 478’’ Morning, Afternoon and Evening SP 2 Notore Road by Notore Garden Camp, Onne N 040 44’. 147’’ E007o 08’. 526’’ Morning, Afternoon and Evening

SP 3 Onne (Trailer park) Junction by East-West Road N 040 45’. 510’’ E 0070 09’. 516’’ Morning, Afternoon and Evening

SP 4 Port Harcourt Refinery Junction by East-West Road, Alesa N 040 47’. 066’’ E 0070 07’. 001’’ Morning, Afternoon and Evening

SP 5 Agbonchia by Zina Motel Junction Eleme N 04047’. 867’’ E 0070 07’. 358’’ Morning, Afternoon and Evening

SP 6 Eleme Petrochemical (Ndorama gate) Aleto, Eleme N 040 48’. 744’’ E 0070 05’. 842’’ Morning, Afternoon and Evening

SP 7 Sandfilled Roundabout, Akpajo N 040 49’. 402’’ E 0070 05’. 276’’ Morning, Afternoon and Evening

SP 8 Okoloma Afam by Afam Power Plant N 040 51’. 058’’ E 0070 15’. 088’’ Morning, Afternoon and Evening

SP 9 Izuoma Asa by Dominican College N 040 51’. 458’’ E 0070 10’. 717’’ Morning, Afternoon and Evening

SP 10 Oyigbo by Eke Oyigbo Market N 040 52’. 561’’ E 0070 08’. 889’’ Morning, Afternoon and Evening

SP 11 Oyigbo Junction by Port Harcourt-Aba Road N 040 52’. 852’’ E 0070 07’. 959’’ Morning, Afternoon and Evening

SP 12 Shell Flow Station/Location Junction, Umuebulu 4, Etche N 040 53’. 6107’’ E 0070 07’. 302’’ Morning, Afternoon and Evening

SP 13 Shell Gas Plant, Umuebulu 4, Etche N 040 53’. 674’’ E 0070 07’ 129’’ Morning, Afternoon and Evening

Table 1: Sampling Points Key, Description of Sampling Points, Coordinate and Frequency of Monitoring Cont’d.

Sampling Description of Sampling Points Coordinates Frequency of Monitoring/Hourly Point Code: SP 14 Igbo Etche Junction-Umasikpo, Igbo Etche N 040 56’. 788’’ E 0070 04’. 94’’ Morning, Afternoon and Evening

SP 15 Eleme Junction by Oilmill Bus Stop N 040 51’. 267’’ E 0070 03’. 843’’ Morning, Afternoon and Evening

SP 16 Rumukrushi Bus Stop by Rumukrushi Park N 040 50’. 992’’ E 0070 03’. 201’’ Morning, Afternoon and Evening

SP 17 Rumukrushi Tank by East-West Road N 040 51’. 859’’ E 0070 03’. 364’’ Morning, Afternoon and Evening

SP18 Eneka Roundabout, Rumu-olukwu, Eneka N 040 53’. 756’’ E 0070 02’. 392’’ Morning, Afternoon and Evening

SP 19 Artillery Junction by Okporo Road N 040 50’. 612’’ E 0070 02’. 298’’ Morning, Afternoon and Evening

SP 20 Rumuobiakani Junction by Oginigba/Old Aba Road N040 50’. 208’’ E 0070 02’. 066’’ Morning, Afternoon and Evening

SP 21 Rumuomasi in-between Aba Road Rumuomasi Junction N 040 50’. 236’’ E 0070 01’ 548’’ Morning, Afternoon and Evening and Old Aba Road

SP 22 Rumuodara Junction by East-West Road N 040 51’. 622’’ E 0070 01’ 776’’ Morning, Afternoon and Evening

SP 23 Eliozu Flyover N 040 51’. 570’’ E 0070 01’. 307’’ Morning, Afternoon and Evening

SP24 Rukpokwu Roundabout N 040 53’. 447’’ E 0070 00’. 140’’ Morning, Afternoon and Evening

SP 25 Igwuruta Roundabout by Air Port Road N 040 57’. 400’’ E 0070 00’. 690’’ Morning, Afternoon and Evening

SP 26 Port Harcourt International Air Port Junction/Roundabout N 040 58’. 858’’ E 0060 56’. 989’’ Morning, Afternoon and Evening Omagwa

SP 27 Greater Port Harcourt in-Between Air Port and Obirikwere N 040 57’. 421’’ E 0060 56’. 965’’ Morning, Afternoon and Evening Road by H and H Engineering Ltd

Table 1: Sampling Points Key, Description of Sampling Points, Coordinates and Frequency of Monitoring Cont’d.

Sampling Description of Sampling Points Coordinates Frequency of Monitoring/Hourly Point Code: SP 28 Aluu Roundabout, Aluu N 040 56’. 019’’ E 0060 56’. 547’’ Morning, Afternoon and Evening

SP 29 Choba Junction, By Uniport East-West Road N 040 53’. 917’’ E 0060 54’. 400’’ Morning, Afternoon and Evening

SP 30 Rumuosi Junction by East-West Road N 040 52’. 951’’ E 0060 56’. 461’’ Morning, Afternoon and Evening

SP 31 Nkpolu Junction by East-West Road N 040 52’. 158’’ E 0060 58’. 862’’ Morning, Afternoon and Evening

SP 32 Rumuokoro Junction/Roundabout N 040 52’. 612’’ E 0060 59’. 855’’ Morning, Afternoon and Evening

SP 33 Wimpy Junction by Ikwere Road N 040 49’. 835’’ E 0060 58’. 924’’ Morning, Afternoon and Evening

SP 34 Location Junction by NTA and Ada George Road N 040 51’. 137’’ E 0060 58’. 516’’ Morning, Afternoon and Evening

SP 35 Rumuokuta Junction/ Roundabout N 040 50’. 271’’ E 0060 59’. 308’’ Morning, Afternoon and Evening

SP 36 Rumuigbo by Obiwali Junction N 040 50’. 843’’ E 0060 59’. 421’’ Morning, Afternoon and Evening

SP 37 Akar Base, Saipem Gate, Rumuolumeni N 040 46’. 550’’ E 0060 58’. 013’’ Morning, Afternoon and Evening

SP38 University of Education’s Gate Rumuolumeni N 040 48’. 420’’ E 0060 56’. 061’’ Morning, Afternoon and Evening

SP 39 Eagle Island Gate by Illoabuchi T Junction N 040 47’. 164’’ E 0060 58’. 806’’ Morning, Afternoon and Evening

SP40 Agip Junction by Agip Flyover N 040 48’. 825’’ E 0060 59’. 018’’ Morning, Afternoon and Evening

SP41 Mile 3 by Mile 3 Park N 040 48’. 158’’ E 0060 59’. 409’’ Morning, Afternoon and Evening SP 42 Illoabuchi by Ukuoto Street, Mile 2 N 040 47’. 451’’ E 0060 59’. 279’’ Morning, Afternoon and Evening

0 0 SP 43 Ikoku by Eko Bank N 04 48’. 043’’ E 006 59’. 698’’ Morning, Afternoon and Evening

Table 1: Sampling Points Key, Description of Sampling Points, Coordinate and Frequency of Monitoring Cont’d.

Sampling Description of Sampling Points Coordinates Frequency of Monitoring/Hourly Point Code: SP 44 Waterline Junction by Olu Obansanjo/Port Harcourt Aba N 040 49’. 016’’ E 0070 00’. 562’’ Morning, Afternoon and Evening Road SP 45 Garrison Junction by Ogunabali/Port Harcourt Aba Road N 040 48’ 335’’ E 0070 00’. 566’’ Morning, Afternoon and Evening

SP 46 Rumuola Junction/Flyover by Port Harcourt Aba Road N 040 49’. 945’’ E 0070 00’. 315’’ Morning, Afternoon and Evening

SP 47 Woji by Woji Town Hall N 040 49’. 820’’ E 0070 03’’ 018’’ Morning, Afternoon and Evening SP 48 YKC Junction, Woji N 040 49’. 338’’ E 0070 03’. 228’’ Morning, Afternoon and Evening SP 49 Elelenwo by Woji T-Junction/Health Center N 040 49’. 807’’ E 0070 04’. 279’’ Morning, Afternoon and Evening SP 50 Transamadi by Slaughter Junction/ Roundabout N 040 48’. 760’’ E 0070 02’ 688’’ Morning, Afternoon and Evening SP 51 Gbalajam N 040 48’. 713’’ E 0070 04’. 208’’ Morning, Afternoon and Evening SP 52 Mothercat Junction, Trans-amadi N 040 48’. 304’’ E 0070 01’. 683’’ Morning, Afternoon and Evening SP53 Trans-amadi Gas Turbine by Total E & P Back Gate N 040 49’. 003’’ E 0070 01’. 834’’ Morning, Afternoon and Evening

SP 54 Abuloma Jetty Road by Okuru Link Road, Abuloma N 040 46’. 930’’ E 0070 03’. 277’’ Morning, Afternoon and Evening

SP55 Sansung Roundabout/Junction by Peter Odilli Road N 040 47’. 728’’ E 0070 02’. 316’’ Morning, Afternoon and Evening

SP 56 Nkpogu Junction, Transamadi N 040 48’ 570’’ E 0070 00’. 994’’ Morning, Afternoon and Evening SP 57 Eastern By Pass Roundabout/Junction N 040 47’. 583’’ E 0070 00’. 948’’ Morning, Afternoon and Evening SP 58 Abonnema Jetty by Shell Kidney Island N 040 46’. 583’’ E 0070 00’. 315’’ Morning, Afternoon and Evening

Table 1: Sampling Points Key, Description of Sampling Points, Coordinate and Frequency of Monitoring Cont’d.

Sampling Description of Sampling Points Coordinates Frequency of Monitoring/Hourly Point Code: SP 59 Tombia Extension by Prof Abowie GRA Phase II N 040 49’. 509’’ E 0060 59’. 454’’ Morning, Afternoon and Evening

SP 60 King Perekule Junction by Evo street GRA Phase II N 040 49’. 171’’ E 0070 00’. 070’’ Morning, Afternoon and Evening

SP 61 Mile 1 Opposite Isaac Boro Park N 040 47’. 237’’ E 0070 00’. 229’’ Morning, Afternoon and Evening

SP 62 Rumuibekwe by Gram Diagnostic Laboratory N 040 50’. 375’’ E 0070 03’. 003’’ Morning, Afternoon and Evening

SP 63 Stadium Road by Mummy B Junction N 040 49’. 615’’ E 0070 00’. 930’’ Morning, Afternoon and Evening

SP 64 BMSH Junction Old GRA N 040 46’. 817’’ E 0070 00’. 905’’ Morning, Afternoon and Evening

SP 65 Moscow Road by NNPC/House of Assembly Complex N 040 46’. 159’’ E 0070 01’. 166’’ Morning, Afternoon and Evening

SP66 Lagos Bus Stop, Town, Port Harcourt N 040 45’. 697’’ E 0070 01’. 132’’ Morning, Afternoon and Evening

SP 67 UPE Junction, Borokiri, Port Harcourt N 040 44’. 930’’ E 0070 02’. 489’’ Morning, Afternoon and Evening

SP 68 Nembe Water Side, Port Harcourt N 00 45’. 500’’ E 00070 01’. 361’’ Morning, Afternoon and Evening

SP 69 Ibeto Cement Gate, Bundu Ama Estate, N 040 44’. 879’’ E 0070 00’. 379’’ Morning, Afternoon and Evening Port Harcourt SP70 Makobar Area, Town Port Harcourt N 040 45’. 509’’ E 0070 00’. 533’’ Morning, Afternoon and Evening

SP 71 Agudama Avenue Junction D/Line, N 040 48’. 367’’ E 0070 00’. 166’’ Morning, Afternoon and Evening Port Harcourt

3. RESULTS AND DISCUSSION

Computation of Pollutant Standard Index (PSI) and Air Quality Index (AQI) in Eleme area The PSI is a sub air quality index (sub-AQI), a number which indicates the concentration level of each pollutant in the air. Pollutant standards indices (PSI) were computed using concentrations of criteria pollutants (SO2, NO2, CO, PM10 and PM2.5). The computed PSI for each pollutant in the dry season in Eleme area are shown in Figures 2 to 6, while plots of corresponding AQI are shown in Figure 7. Computed PSI showed high values of SO2, NO2 and PM2.5 (Figure 2 to 6). This implies that SO2, NO2 and PM2.5 are the main air pollutants prevailing in the Eleme area in the dry season. This may be as a result of industrial activities in the area. The air quality indices computed for the Eleme area in the dry season (Table 2 and Figure 7) showed very unhealthy values (between 201 and 300) at station SP1, SP2, SP5 and SP6. This may potentially affect the entire exposed population, thus the people in these areas may experience more serious health effects. Similarly, stations SP3, SP4 and SP7 (Table 2) showed hazardous values (between 301 and 500). This implies that the entire people in these areas may experience more severe health effects.

Table 2: Dry Season Pollutant Standard Index and Air Quality Index in Eleme Area Sampling SO2 NO2 CO PM10 PM2.5 Point PSI PSI PSI PSI PSI AQI AQI rating SP1 499.5 77.7 234.7 253.9 128.5 238.9 Very Unhealthy SP2 499.5 266.5 197.6 160.3 114.0 247.6 Very Unhealthy SP3 887.1 266.5 288.6 634.1 149.1 445.1 Hazardous SP4 665.7 266.5 350.7 214.0 140.2 327.4 Hazardous SP5 499.5 266.5 104.4 330.0 148.4 269.8 Very Unhealthy SP6 534.8 303.2 309.1 208.7 142.6 299.7 Very Unhealthy SP7 534.8 211.1 115.3 576.6 153.4 318.2 Hazardous

1000.0 887.1 Dry Season SO2 PSI 900.0

800.0 Wet Season SO2 PSI 700.0 665.7 534.8 534.8 600.0 499.5 499.5 499.5 500.0

400.0 PSI Values PSI 300.0 200.0 100.0 0.0 SP1 SP2 SP3 SP4 SP5 SP6 SP7 Location

Figure 2: Computed Pollutant Standard Index of SO2 around Eleme Area

350.0 Dry Season NO2 PSI Wet Season NO2 PSI 303.2 300.0 266.5 266.5 266.5 266.5

250.0 211.1 200.0

150.0 PSI values PSI 100.0 77.7 50.0 0.0 SP1 SP2 SP3 SP4 SP5 SP6 SP7 Location

Figure 3: Computed Pollutant Standard Index of NO2 around Eleme Area Dry Season CO PSI Wet Season CO PSI 400.0 350.7 350.0 309.1 288.6 300.0 234.7 250.0 197.6 200.0

PSI values PSI 150.0 104.4 115.3 100.0 50.0 0.0 SP1 SP2 SP3 SP4 SP5 SP6 SP7 Location

Figure 4: Computed Pollutant Standard Index of CO around Eleme Area

700.0 634.1 Dry Season PM10 PSI 576.6 600.0 Wet Season PM10 PSI 500.0

400.0 330.0 300.0 253.9

PSI values PSI 214.0 208.7 200.0 160.3 100.0 0.0 SP1 SP2 SP3 SP4 SP5 SP6 SP7 Location

Figure 5: Computed Pollutant Standard Index of PM10 around Eleme Area 13

Dry Season PM2.5 PSI Wet Season PM2.5 PSI 180.0 149.1 148.4 153.4 160.0 140.2 142.6 140.0 128.5 114.0 120.0 100.0 80.0

PSI values PSI 60.0 40.0 20.0 0.0 SP1 SP2 SP3 SP4 SP5 SP6 SP7 Location

Figure 6: Computed Pollutant Standard Index of PM2.5 around Eleme Area Dry Season AQI Values Wet Season AQI Values 500.0 445.1 450.0 400.0 327.4 318.2 350.0 299.7 300.0 269.8 238.9 247.6 250.0

200.0 AQI Values AQI 150.0 100.0 50.0 0.0 SP1 SP2 SP3 SP4 SP5 SP6 SP7 Location

Figure 7: Computed Air Quality Index around Eleme Area Assessment of Air Quality Index of Etche area The computed PSI for each pollutant in the dry season in Etche area are shown in Figures 8 to 12, while plots of corresponding AQI values are shown in Figure 13. Computed PSI (Figure 8 to 12) showed that SO2, NO2 and PM2.5 are the main cause of pollution in the area, while PM10 pollution levels are higher in the dry season. This implies that SO2, NO2, PM2.5 and PM10 are the main air pollutants prevailing in the Etche area. This may be as a result of road construction activities and gas flaring in the area.The air quality indices computed for the Etche area in the dry season (Table 3 and Figure 13) showed hazardous air quality around station SP12 (between 300 and 500) which may severely affect the health of people in the area. Station SP13 showed unhealthy air quality for sensitive groups, while station SP14 showed unhealthy air quality which may affect everyone in the area particularly members of sensitive groups may be more affected. Table 3: Dry Season Pollutant Standard Index and Air Quality Index in Etche area

Sampling SO2 NO2 CO PM10 PM2.5 Point PSI PSI PSI PSI PSI AQI AQI Rating SP12 499.5 266.5 35.9 693.3 153.8 329.8 Hazardous SP13 0.0 277.6 21.4 130.4 110.5 108.0 Unhealthy for Sensitive Groups SP14 0.0 105.5 40.1 558.3 128.9 166.6 Unhealthy

600.0 500.0 400.0 300.0 Dry Season SO2 PSI

PSI values PSI 200.0 100.0 Wet Season SO2 PSI 0.0 SP12 SP13 SP14 Location

Figure 8: Computed Pollutant Standard Index of SO2 around Etche Area

300.0 250.0 200.0 150.0 Dry Season NO2 PSI

PSI values PSI 100.0 Wet Season NO2 PSI 50.0 0.0 SP12 SP13 SP14 Location

Figure 9: Computed Pollutant Standard Index of NO2 around Etche Area

50.0 40.0 30.0

20.0 Dry Season CO PSI PSI values PSI 10.0 Wet Season CO PSI 0.0 SP12 SP13 SP14 Location

Figure 10: Computed Pollutant Standard Index of CO around Etche Area

800.0 700.0 600.0 500.0 400.0 Dry Season PM10 PSI

300.0 PSI values PSI 200.0 Wet Season PM10 PSI 100.0 0.0 SP12 SP13 SP14 Location

Figure 11: Computed Pollutant Standard Index of PM10 around Etche Area

180.0 160.0 140.0 120.0 100.0 80.0 Dry Season PM2.5 PSI

PSI values PSI 60.0 Wet Season PM2.5 PSI 40.0 20.0 0.0 SP12 SP13 SP14 Location

Figure 12: Computed Pollutant Standard Index of PM2.5 around Etche Area

350.0 300.0 250.0 200.0 150.0 Dry Season AQI values AQI values AQI 100.0 Wet Season AQI values 50.0 0.0 SP12 SP13 SP14 Location

Figure 13: Computed Air Quality Index around Etche Area 16

Assessment of Air Quality Index of Ikwerre Local Government Area (LGA) The computed PSI for each pollutant in the dry season in Ikwerre LGA are shown in Figures 14 to 18, while plots of corresponding AQI values are shown in Figure 19. Computed PSI (Figure 14 to 18) showed that SO2 is the main cause of pollution in the dry season in the area (Table 4).Computed Air Quality Indices for Ikwerre LGA in the dry season (Table 4) showed moderate air quality around station SP25, this may pose a moderate health concern for a very small number of people with respiratory symptoms. Station SP26 showed unhealthy air quality which may affect the health of everyone in the area. Similarly, station SP27 showed unhealthy air quality for sensitive groups while SP28 showed very unhealthy air quality, this may pose widespread health effects among the people in this area, and members of sensitive groups may experience more serious effects.

Table 4: Dry Season Pollutant Standard Index and Air Quality Index in Ikwerre LGA Sampling SO2 NO2 CO PM10 PM2.5 Point PSI PSI PSI PSI PSI AQI AQI Rating SP25 208.0 0.0 40.1 61.0 57.8 73.4 Moderate SP26 499.5 211.1 27.5 82.0 63.4 176.7 Unhealthy Unhealthy for Sensitive SP27 499.5 0.0 23.7 51.5 56.1 126.2 Groups SP28 499.5 283.1 39.0 458.4 86.2 273.3 Very Unhealthy

600.0 499.5 499.5 499.5 500.0 400.0 300.0 230.9 208.0 Dry Season SO2 PSI

PSI values PSI 200.0 124.4 Wet Season SO2 PSI 100.0 0.0 0.0 0.0 SP25 SP26 SP27 SP28 Location

Figure 14: Computed Pollutant Standard Index of SO2 around Ikwerre LGA

300.0 283.1 250.0 211.1 200.0 150.0 Dry Season NO2 PSI 100.0 Wet Season NO2 PSI PSI values PSI 50.0 0.0 0.0 0.0 SP25 SP26 SP27 SP28 Location

Figure 15: Computed Pollutant Standard Index of NO2 around Ikwerre LGA

60.0 40.1 39.0 40.0 33.2 27.5 23.7 16.8 13.0 Dry Season CO PSI

20.0 6.9 PSI values PSI Wet Season CO PSI 0.0 SP25 SP26 SP27 SP28 Location

Figure 16: Computed Pollutant Standard Index of CO around Ikwerre LGA

500.0

400.0

300.0

200.0 Dry Season PM10 PSI PSI values PSI Wet Season PM10 PSI 100.0

0.0 SP25 SP26 SP27 SP28 Location

Figure 17: Computed Pollutant Standard Index PM10 around Ikwerre LGA

100.0 90.0 80.0 70.0 60.0 50.0 Dry Season PM2.5 PSI

40.0 PSI values PSI 30.0 Wet Season PM2.5 PSI 20.0 values 10.0 0.0 SP25 SP26 SP27 SP28 Location

Figure 18: Computed Pollutant Standard Index PM2.5 around Ikwerre LGA

300.0 250.0 200.0 150.0 Dry Season AQI Values

100.0 AQI Values AQI 50.0 Wet Season AQI Values 0.0 SP25 SP26 SP27 SP28 Location

Figure 19: Computed Air Quality Index around Ikwerre LGA

Assessment of Air Quality Index of Obio/Akpor Area The computed PSI for each pollutant in the dry season in Obio/Akpor area are shown in Figures 20 to 24, while plots of corresponding AQI values are shown in Figure 25. Computed PSI (Figure 20 to 24) showed that SO2, NO2, CO, PM10 and PM2.5 are the main cause of pollution in the dry season in the area, however, the pollution levels are higher in the dry season compared to the wet season. This implies that there is high pollution in Obio/Akpor which may be caused by vehicular exhaust emissions, gas flaring, oil and gas exploitation and industrial activities as well as road construction activities in the area.The dry season computed air quality indices for Obio/Akpor area (Table 5 and Figure 25) showed very unhealthy air quality around stations SP15, SP16, SP20, SP21, SP22, SP23, SP29, SP32, SP36, SP37, SP38, SP46, SP50, and SP63. This may pose widespread health effects among the people in these areas, and members of sensitive groups may experience more serious effects. Stations SP17, SP18, SP19, SP24, SP30, SP31, SP33, SP35, SP40, and SP62 showed unhealthy air quality in the dry season (Table 5). Everyone in these stations may experience health effects; particularly sensitive people with respiratory symptoms may experience more serious health effects. Stations SP34 and SP47 showed moderate air quality in the dry season. This may affect few people and those who are unusually sensitive to particles quality may experience respiratory symptoms. Stations SP48 and SP51 showed unhealthy air quality for sensitive groups in the dry season. This may affect only sensitive groups while the general public may not be affected. Station SP49 indicated hazardous air quality which may affect the entire people with serious health effects.

Table 5: Dry Season Pollutant Standard Index and Air Quality Index in Obio/Akpor Area

Sampling SO2 NO2 CO PM10 PM2.5 Point PSI PSI PSI PSI PSI AQI AQI Rating SP15 635.4 288.6 325.8 121.8 109.3 296.2 Very Unhealthy SP16 565.0 211.0 216.5 117.3 94.7 240.9 Very Unhealthy SP17 330.8 288.6 77.0 152.8 121.3 194.1 Unhealthy SP18 534.8 77.7 46.0 209.0 100.7 193.6 Unhealthy SP19 208.0 283.1 234.7 97.6 101.1 184.9 Unhealthy SP20 514.6 77.7 190.0 113.8 108.5 200.9 Very Unhealthy SP21 499.5 77.7 247.6 108.7 109.0 208.5 Very Unhealthy SP22 736.1 266.5 96.0 89.9 81.5 254.0 Very Unhealthy SP23 499.5 283.1 160.6 66.2 77.6 217.4 Very Unhealthy SP24 615.3 77.7 51.0 99.5 77.7 184.2 Unhealthy SP29 499.5 273.6 243.5 252.7 94.4 272.8 Very Unhealthy SP30 208.0 273.1 49.0 204.3 84.9 163.9 Unhealthy SP31 499.5 77.7 80.0 81.4 70.3 161.8 Unhealthy SP32 499.5 471.9 297.6 125.9 83.7 295.7 Very Unhealthy SP33 499.5 0.0 216.5 79.3 83.8 175.8 Unhealthy SP34 0.0 0.0 277.6 74.6 79.3 86.3 Moderate SP35 499.5 77.7 178.8 91.0 95.8 188.6 Unhealthy SP36 499.5 266.5 220.6 57.8 62.3 221.3 Very Unhealthy SP37 519.7 322.0 284.1 269.4 84.0 295.8 Very Unhealthy SP38 565.0 277.6 54.0 59.1 64.4 204.0 Very Unhealthy SP40 499.5 77.7 115.7 52.6 68.6 162.8 Unhealthy SP46 534.8 288.6 319.2 127.2 108.5 275.7 Very Unhealthy SP47 0.0 0.0 79.0 117.1 125.1 64.2 Moderate SP48 0.0 0.0 92.0 376.3 130.0 119.7 Unhealthy for Sensitive Groups SP49 499.5 77.7 185.3 1827.0 158.5 549.6 Hazardous SP50 499.5 77.7 234.7 282.0 86.1 236.0 Very Unhealthy SP51 499.5 0.0 15.0 81.6 63.9 132.0 Unhealthy for Sensitive Groups SP62 499.5 266.5 21.0 106.9 97.8 198.3 Unhealthy SP63 499.5 266.5 295.3 63.0 65.2 237.9 Very Unhealthy

800.0 Dry Season SO2 PSI Wet Season SO2 PSI 700.0 600.0 500.0 400.0

300.0 PSI values PSI 200.0 100.0 0.0 Location

Figure 20: Computed Pollutant Standard Index of SO2 around Obio/Akpor Area

500.0 450.0 Dry Season NO2 PSI 400.0 Wet Season NO2 PSI 350.0 300.0 250.0 200.0

PSI values PSI 150.0 100.0 50.0

0.0

SP18 SP51 SP15 SP16 SP17 SP19 SP20 SP21 SP22 SP23 SP24 SP29 SP30 SP31 SP32 SP33 SP34 SP35 SP36 SP37 SP38 SP40 SP46 SP47 SP48 SP49 SP50 SP62 SP63 Location

Figure 21: Computed Pollutant Standard Index of NO2 around Obio/Akpor Area 350.0 Dry Season CO PSI 300.0 Wet Season CO PSI 250.0 200.0 150.0

PSI values PSI 100.0 50.0

0.0

SP17 SP46 SP47 SP15 SP16 SP18 SP19 SP20 SP21 SP22 SP23 SP24 SP29 SP30 SP31 SP32 SP33 SP34 SP35 SP36 SP37 SP38 SP40 SP48 SP49 SP50 SP51 SP62 SP63 Location

Figure 22: Computed Pollutant Standard Index of CO around Obio/Akpor Area

2000.0 Dry Season PM10 PSI Wet Season PM10 PSI

1500.0

1000.0

PSI values PSI 500.0

0.0

SP30 SP15 SP16 SP17 SP18 SP19 SP20 SP21 SP22 SP23 SP24 SP29 SP31 SP32 SP33 SP34 SP35 SP36 SP37 SP38 SP40 SP46 SP47 SP48 SP49 SP50 SP51 SP62 SP63 Location

Figure 23: Computed Pollutant Standard Index of PM10 around Obio/Akpor Area

180.0 Dry Season PM2.5 PSI 160.0 Wet Season PM2.5 PSI 140.0 120.0 100.0 80.0

PSI values PSI 60.0 40.0 20.0

0.0

SP48 SP63 SP15 SP16 SP17 SP18 SP19 SP20 SP21 SP22 SP23 SP24 SP29 SP30 SP31 SP32 SP33 SP34 SP35 SP36 SP37 SP38 SP40 SP46 SP47 SP49 SP50 SP51 SP62 Location

Figure 24: Computed Pollutant Standard Index of PM2.5 around Obio/Akpor Area

600.0 500.0 Dry Season AQI Values 400.0 Wet Season AQI Values 300.0

200.0 AQI Values AQI 100.0

0.0

SP49 SP15 SP16 SP17 SP18 SP19 SP20 SP21 SP22 SP23 SP24 SP29 SP30 SP31 SP32 SP33 SP34 SP35 SP36 SP37 SP38 SP40 SP46 SP47 SP48 SP50 SP51 SP62 SP63 Location

Figure 25: Computed Air Quality Index around Obio/Akpor Area

Assessment of Air Quality Index of Oyigbo Area The computed PSI for each pollutant in the dry season in Oyigbo area are shown in Figures 26 to 30, while plots of corresponding AQI values are shown in Figure 31. Computed PSI (Figure 26 to 30) showed that SO2, NO2 and PM2.5 are the main cause of pollution in the area in the dry season. The dry season computed air quality indices for Oyigbo area (Table 6) showed unhealthy air quality around station SP8. This may affect the health of everyone in the area; especially sensitive people with respiratory symptoms may experience more serious health effects. Station SP10 showed unhealthy air quality for sensitive groups in the dry season. This may affect only sensitive groups while the general public may not be affected. Also, stations SP9 and SP11 indicated hazardous air quality which may affect the entire people with serious health effects.

Table 6: Dry Season Pollutant Standard Index and Air Quality Index in Oyigbo Area

Sampling SO2 NO2 CO PM10 PM2.5 Point PSI PSI PSI PSI PSI AQI AQI Rating SP8 499.5 272.0 69.0 71.1 70.0 196.3 Unhealthy SP9 499.5 266.7 46.0 603.9 110.2 305.3 Hazardous Unhealthy for Sensitive SP10 0.0 77.7 55.0 414.3 122.5 133.9 Groups SP11 504.6 266.5 284.1 794.5 128.8 395.7 Hazardous

600.0 Dry season SO2 PSI Wet season SO2 PSI 500.0 400.0 300.0

PSI values PSI 200.0 100.0 0.0 SP8 SP9 SP10 SP11 Location

Figure 26: Computed Pollutant Standard Index of SO2 around Oyigbo Area

300.0 Dry season NO2 PSI Wet season NO2 PSI 250.0 200.0 150.0

PSI values PSI 100.0 50.0 0.0 SP8 SP9 SP10 SP11 Location

Figure 27: Computed Pollutant Standard Index of NO2 around Oyigbo Area

300.0

250.0 Dry season CO PSI Wet season CO PSI 200.0

150.0

PSI values PSI 100.0

50.0

0.0 SP8 SP9 SP10 SP11 Location

Figure 28: Computed Pollutant Standard Index of CO around Oyigbo Area

900.0 Dry season PM10 PSI 800.0 Wet season PM10 PSI 700.0 600.0 500.0 400.0

PSI values PSI 300.0 200.0 100.0 0.0 SP8 SP9 SP10 SP11 Location

Figure 29: Computed Pollutant Standard Index of PM10 around Oyigbo Area

140.0 Dry season PM2.5 PSI Wet season PM2.5 PSI 120.0 100.0 80.0

60.0 PSI values PSI 40.0 20.0 0.0 SP8 SP9 SP10 SP11 Location

Figure 30: Computed Pollutant Standard Index of PM2.5 around Oyigbo Area

500.0 Dry season AQI Values Wet season AQI Values 400.0

300.0

200.0 PSI values PSI 100.0

0.0 SP8 SP9 SP10 SP11 Location

Figure 31: Computed Air Quality Index for Oyigbo Area

Assessment of Air Quality Index of Port Harcourt Area The computed PSI for each pollutant in the dry season in Port Harcourt area are shown in Figures 32 to 36, while plots of corresponding AQI values are shown in Figure 37. Computed PSI (Figures 32 to 36) showed that SO2, NO2, CO, PM10 and PM2.5 are the main cause of pollution in the dry season in the area, however, the pollution levels are higher in the dry season compared to the wet season. This implies that there is high pollution in Port Harcourt which may be caused by vehicular exhaust emissions, gas flaring, oil and gas exploitation, industrial activities as well as road construction activities in the area. The dry season computed air quality indices for Port Harcourt area (Table 7 and Figure 37) showed very unhealthy air quality around stations SP45, SP66 and SP68. This may cause widespread health problems among the people in these areas, and members of sensitive groups may experience more serious effects. Stations SP42, SP43, SP44, SP53, SP57, SP58, SP59, SP65, SP67 and SP70 showed unhealthy air quality in the dry season (Table 7). This may affect the health of everyone in these stations; particularly sensitive people with respiratory symptoms may experience more severe health effects. Stations SP41, SP55, SP64 and SP69 showed unhealthy air quality for sensitive groups in the dry season. This may affect only sensitive groups while the general public may not be affected. Stations SP52, SP54, SP56 and SP61 indicated hazardous air quality which may have serious health effects on the entire people. Also, stations SP39, SP60 and SP71 showed good air quality which poses minor or no health risk to the people.

Table 7: Dry Season Pollutant Standard Index and Air Quality Index in Port Harcourt Area Sampling SO2 NO2 CO PM10 PM2.5 Point PSI PSI PSI PSI PSI AQI AQI Rating SP39 0.0 0.0 99.0 52.7 61.9 42.7 Good SP41 0.0 77.4 275.3 84.7 87.3 105.0 Unhealthy for Sensitive Groups SP42 499.5 0.0 152.9 99.6 93.6 169.1 Unhealthy SP43 519.7 77.4 121.4 88.8 94.8 180.4 Unhealthy SP44 499.5 0.0 138.6 99.9 89.9 165.6 Unhealthy SP45 499.5 266.5 277.6 128.2 95.8 253.5 Very Unhealthy SP52 0.0 0.0 47.0 6929.0 261.0 1447.4 Hazardous SP53 499.5 266.5 24.0 71.8 79.2 188.2 Unhealthy SP54 499.5 0.0 154.3 1007.0 128.0 357.8 Hazardous SP55 499.5 0.0 34.0 101.1 92.1 145.3 Unhealthy for Sensitive Groups SP56 836.8 266.5 278.8 527.2 116.9 405.2 Hazardous SP57 499.5 266.5 27.0 116.2 86.5 199.1 Unhealthy SP58 499.5 0.0 110.0 89.0 92.7 158.2 Unhealthy SP59 499.5 0.0 42.0 114.5 106.5 152.5 Unhealthy

SP60 0.0 0.0 31.0 78.2 76.9 37.2 Good SP61 801.6 289.8 178.6 133.1 118.1 304.2 Hazardous SP64 499.5 0.0 82.0 45.3 57.6 136.9 Unhealthy for Sensitive Groups SP65 499.5 266.5 73.0 67.5 62.9 193.9 Unhealthy SP66 665.7 0.0 357.5 83.8 89.4 239.3 Very Unhealthy SP67 499.5 0.0 142.9 69.7 75.6 157.5 Unhealthy SP68 499.5 0.0 347.5 105.8 63.5 203.3 Very Unhealthy SP69 499.5 0.0 0.0 65.8 58.0 124.7 Unhealthy for Sensitive Groups SP70 499.5 0.0 228.8 153.5 72.8 190.9 Unhealthy SP71 0.0 0.0 76.0 46.4 54.7 35.4 Good

900.0 Dr season SO2 PSI Wet season SO2 PSI 800.0 700.0 600.0 500.0 400.0

PSI values PSI 300.0 200.0 100.0

0.0

SP56 SP41 SP42 SP43 SP44 SP45 SP52 SP53 SP54 SP55 SP57 SP58 SP59 SP60 SP61 SP64 SP65 SP66 SP67 SP68 SP69 SP70 SP71 SP39 Location

Figure 32: Computed Pollutant Standard Index of SO2 around Port Harcourt Area

350.0 Dry season NO2 PSI 300.0 Wet season NO2 PSI 250.0 200.0

150.0 PSI values PSI 100.0 50.0

0.0

SP39 SP60 SP41 SP42 SP43 SP44 SP45 SP52 SP53 SP54 SP55 SP56 SP57 SP58 SP59 SP61 SP64 SP65 SP66 SP67 SP68 SP69 SP70 SP71 Location

Figure 33: Computed Pollutant Standard Index of NO2 around Port Harcourt Area

400.0 Dry season CO PSI 350.0 Wet season CO PSI 300.0 250.0 200.0 150.0

PSI values PSI 100.0 50.0

0.0

SP44 SP67 SP39 SP41 SP42 SP43 SP45 SP52 SP53 SP54 SP55 SP56 SP57 SP58 SP59 SP60 SP61 SP64 SP65 SP66 SP68 SP69 SP70 SP71 Location

Figure 34: Computed Pollutant Standard Index of CO around Port Harcourt Area

8000.0 Dry season PM10 PSI 7000.0 Wet season PM10 PSI 6000.0 5000.0 4000.0 3000.0

PSI values PSI 2000.0 1000.0

0.0

SP66 SP39 SP41 SP42 SP43 SP44 SP45 SP52 SP53 SP54 SP55 SP56 SP57 SP58 SP59 SP60 SP61 SP64 SP65 SP67 SP68 SP69 SP70 SP71 Location

Figure 35: Computed Pollutant Standard Index of PM10 around Port Harcourt Area

300.0 Dry season PM2.5 PSI 250.0 Wet season PM2.5 PSI 200.0

150.0

100.0 PSI values PSI 50.0

0.0

SP43 SP54 SP59 SP66 SP71 SP39 SP41 SP42 SP44 SP45 SP52 SP53 SP55 SP56 SP57 SP58 SP60 SP61 SP64 SP65 SP67 SP68 SP69 SP70 Location

Figure 36: Computed Pollutant Standard Index of PM2.5 around Port Harcourt Area

1600.0 1400.0 Dry season AQI Values 1200.0 Wet season AQI Values 1000.0 800.0 600.0 400.0 AQI values AQI 200.0

0.0

SP39 SP64 SP71 SP41 SP42 SP43 SP44 SP45 SP52 SP53 SP54 SP55 SP56 SP57 SP58 SP59 SP60 SP61 SP65 SP66 SP67 SP68 SP69 SP70 Location Figure 37: Computed Air Quality Index for Port Harcourt Area

Table 8: Health and Environmental Risk of Air Pollutants

S/No Air Pollutants Effects on Human and Environment 1 SO2 Irritates the nose, throat and airways to cause coughing, wheezing, shortness of breath and a tight feeling around chest. SO2 form acid rain, cause deforestation, detriment to aquatic life and corrode building materials and paints. 2 NO2 Respiratory problems - wheezing, coughing, colds, flu and bronchitis. NO2 is harmful to vegetation- damaging foliage, decreasing growth, reducing crop yields, fade and discolour furnishings and fabrics, reduce visibility and react with surfaces. 3 H2S Exposure to low concentrations of hydrogen sulphide may cause irritation to the eyes, nose or throat - affects asthmatic patient, but acute exposure causes nausea, headaches, delirium, disturbed equilibrium, tremors, convulsions, skin and eye irritation. 4 VOCs Affects the eyes, nose and throat irritation; headaches, loss of coordination, nausea, damage to the liver, kidney and central nervous systems. 5 CO Causes headache, dizziness, vomiting and nausea, moderate and high level of CO over a long periods of time can be linked with increased risk of heart disease. CO increases the amount of greenhouse gases, which are linked to global warming and climate change. 6 NH3 Expose to high concentration of ammonia in air causes immediate burning of the nose, throat and respiratory tract. This can cause bronchiolar and alveolar edema. While lower concentrations can cause coughing, nose and throat irritation. 7 CH4 Methane has no effect on human health - but it’s a greenhouse gas (global warming). 8 PM2.5 Irregular heartbeat, aggravated asthma, decreased lung function, increased irritation of the airways, coughing or difficulty breathing. 9 PM10 Irregular heartbeat, aggravated asthma, decreased lung function, increased irritation of the airways, coughing or difficulty breathing. 10 TSP Nonfatal heart attacks, irregular heartbeat, aggravated asthma, decreased lung function, increased irritation of the airways, coughing or difficulty breathing. 11 Noise Fatigue from lack of sleep, cardiovascular disease, cognitive impairment, tinnitus, hypertension and vasoconstriction.

4. CONCLUSION

Computed PSI showed that SO2, NO2, CO, PM10 and PM2.5 are the main cause of pollution in the dry season in the study area, however, the pollution levels are higher in the dry season. The results of AQI also indicated that Eleme, Obio/Akpor and Port Harcourt are most polluted areas compared to Oyigbo, Ikwerre LGA and Etche in the dry season.

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