OBSERVATION OF SEASONAL VARIATION AND CHEMICAL ANALYSIS OF PM10

Abstract

The federal capital of Pakistan, Islamabad, is a planned city. Situated within the Potohar Plateau, it is located in the country’s northwest. Compared to other major cities, it is relatively clean. It is considered as much cleaner compared to the other major cities of the country. But the influx from other cities, continuous and rapid development as well as influence from Rawalpindi, Islamabad’s twin city; is deteriorating its air quality at a faster rate. Very few studies have been conducted to account for the air quality situation with primary focus on the industrial sectors and to monitor the background aerosol pollution in Islamabad. To fill the gap, 24- hourly PM10 samples were run once or twice a month for one year within the premises of National University of Science and Technology, Islamabad. The highest PM10 concentration was observed for December 2015, with 295.17 μg/m3, while the lowest was observed for the month of July with 8.37 μg/m3. The influence of meteorological conditions such as temperature, wind speed, wind direction, relative humidity as well as u and v wind vectors was explored using statistical tests. Only relative humidity (RH) had a significant correlation with particulate matter. Whereas, regression analysis showed that temperature, pressure, Wind Direction Index (WDI) and u wind tend to explain 62% variance in the PM10 concentration. The samples were analyzed to determine the presence and concentrations of heavy metals (Cd, Cr, Cu, Fe, Ni, Pb, Zn), using ICP-OES. Of these metals, only copper and nickel had siginificant correlation coefficients with meteorological parameters. Copper had a positive correlation with relative humidity. Whereas, nickel had negative correlation with WDI, and positive correlation with RH and v wind. The order of concentrations followed Zn > Fe > Pb > Cu > Cd > Cr and N. To understand the origins of these heavy metals enrichment factor (EF) was calculated, determining whether they have a crustal or anthropogenic source, by taking Fe as the reference metal. Compared to the local soil, Cd showed the highest enrichment followed by Zn, Cu and Pb, while Cr and Ni showed no enrichment.