Air Pollution We Breathe: Assessing the Air Quality and Human Health Impact in a Megacity of Southeast Asia
HAIDER KHWAJA, Fatim Sannoh, Zafar Fatmi, David Carpenter, Muhayatun Santoso, Azhar Siddique, Kamran Khan, Jahan Zeb, Mirza M. Hussain, Wadsworth Center, University at Albany
Abstract Number: 203
Working Group: Urban Aerosols
Abstract
With 24 million inhabitants and 6.6 million vehicles on the roads, Karachi, Pakistan is one of the most polluted cities in the world. This is the detailed investigation on fine particulate (PM2.5) mass, seasonal and temporal variability, chemical characterization, source apportionment, and health risk assessment at two urban sites (Malir and Kemari) in Karachi, Pakistan. Samples were analyzed for various inorganic components (anions, cations, and trace metals) and black carbon (BC). Several PM2.5 pollution episodes were frequently observed, with annual mean concentrations of 140 ± 179 µg/m³ and 95 ± 40.9 µg/m³ at Kemari and Malir, respectively, 28 and 19 fold higher than the World Health Organization annual guideline (5 µg/m³). Kemari and Malir site had an air quality index (AQI) of 27% and 50% “Unhealthy for sensitive groups” for the winter and fall months, respectively. Annual average BC concentrations were 4.86 ± 5.29 µg/m³ and 4.52 ± 3.68 µg/m³, respectively. Chemical composition at both sites exhibited seasonal variability, with higher concentrations in winter and fall and lower concentrations in summer. A Positive Matrix Factorization (PMF) analysis identified 5 factors, crustal, sea salt, vehicular exhaust, fossil-fuel combustion, and industrial emission. The estimated number of deaths were higher in the colder seasons (fall and winter) at the Kemari (328,794 and 287,814) and Malir (228,406 and 165,737) site, respectively. The non-carcinogenic risk of PM2.5 bound Pb, Fe, Zn, Mn, Cr, Cu and Ni via inhalation exposure were within the acceptable level (< 1) for adults. There was a potential non-carcinogenic and carcinogenic health risk posed by Pb and Cr through inhalation to children. Immediate attention should be paid by the policy makers for emission control strategies due to their significantly high contribution to PM2.5 mass and health risks.