Air Quality and Profile of Inorganic Composition of PM2.5 and Source Apportionment in Karachi, Pakistan

FATIM SANNOH, Zafar Fatmi, David Carpenter, Azhar Siddique, Kamran Khan, Jahan Zeb, Muhayatun Santoso, Mirza M. Hussain, Haider Khwaja, University at Albany

     Abstract Number: 566
     Working Group: Source Apportionment

Abstract
Use of fossil fuel impact the air quality. Air pollution is a public health issue in many developed and developing countries. Exposure to ambient particulate matter (PM2.5) has been associated with an increase of various diseases as far as an excess of mortality. In Pakistan, air pollution accounts for a reduced life expectancy by 60 months but air pollution continues to be a threat to public health. Numerous studies have shown increased morbidity and mortality of COPD, lung cancer, and asthma with long term exposure to fine particulate matter, but effects of short-term exposure to PM2.5 needs to be better assessed in Karachi, Pakistan. The air quality studies in suburban cities of developing countries of Asia needs to be investigated further. We used a time-series analysis to examine the air quality in two cities in Karachi, Pakistan over a period of four seasons. Analysis of samples for anions and cations was performed.

A meteorological data and PM2.5 concentrations over the sampling periods to assess the air quality index. Pearson correlation and Enrichment factor analysis was utilized to identify heavy metals, and backward trajectories to investigate local and long-range emission. Positive matrix factorization (PMF) to measure source apportionment. We examined the risk assessment from short term PM exposure. Based on the time-series PM2.5 concentrations were higher in winter and summer having the lowest pollutant concentrations. BC levels exceeded the mean concentrations of each cycle. Metal analysis showed an influx of metal ions emitted from anthropogenic and natural sources at both sampling sites. Analysis for anions showed consistent elevated levels of sulfate, chloride, and oxalate. And cations analysis had high Ca, Na, and K. Presence of NH4 was observed. Our results indicate fossil fuel combustion, vehicular emission, and sea salt and dust particles as the primary source of PM2.5 and its constituents. Exposure to PM2.5 has shown to influence oxidative stress, pulmonary inflammation, and several severe cardiac events. The PM2.5 forms a major portion of the overall particulate air pollution in Pakistan. We monitored the daily levels of PM2.5 and determined the poor air quality associated with extremely high concentrations of PM2.5, black carbon (BC), metals, and ionic species. This could set in motion implementation of possible emission control strategies by policy makers that might influence air quality standards in Pakistan.