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State of Gaseous Air Pollutants and Resulting Health Effects in a Developing Country of Southeast Asia (Karachi, Pakistan)
OMOSEHIN MOYEBI, Fatim Sannoh, Zafar Fatmi, David Carpenter, Azhar Siddique, Kamran Khan, Jahan Zeb, Mirza M. Hussain, Haider Khwaja, University at Albany, Albany, New York
Abstract Number: 102
Working Group: Translating Aerosol Research for Societal Impact: Science Communication and Public Outreach
Abstract
Karachi is a megacity with severe air pollution problems. There are high emissions of air pollutants from vehicular traffic, industrial activities, and biomass burning in Karachi. The numerous emission sources and rapid growth in population makes Karachi a priority site for air pollution research. The objectives of this study are to i) investigate the levels of gaseous air pollutants in Karachi ii) determine temporal and seasonal variation in levels of various air pollutants, and iii) perform a health impact assessment. Daily samples of gaseous pollutants were collected for six consecutive weeks in each of the four seasons for a year at the Tibet Center. Samples were analyzed for pollutants by ion chromatography. Maximum daily concentrations of NO2 (28.1 ppbv), NO (90 ppbv), O3 (57.8 ppbv), and SO2 (331 ppbv) were recorded in fall, while the highest concentration of HNO3 (9129 pptv) was recorded in spring. Seasonal average concentrations were high in winter for NO2 (4.84 ± 3.35 ppbv), NO (9.47 ± 7.82 ppbv), and O3 (8.92 ± 7.65 ppbv), while HNO3 (629 ± 1316 pptv) and SO2 (20.2 ± 39.4 ppbv) were high in spring and fall, respectively. This reflected the influence of seasonal environmental characteristics such as photochemical activities, meteorological conditions, and source and sink strength. The observed SO2 seasonal average in fall was 5 times higher than the summertime. Health impact assessment estimated an increase of 1200 and 569 deaths due to short-term exposure to SO2 in fall and spring, respectively. Chronic daily intake estimated risk per 1000 were 0.99, 0.47, 0.45, and 0.26 for SO2 in fall, NO and O3 in winter, and NO2 in spring. This study confirmed the effect of poor urban air quality on human health and demonstrated the influence of photochemical activity on the formation of secondary pollutants.