Elemental Composition of Particulate Matter in South-Asian Megacity (Faisalabad-Pakistan): Seasonal Behaviors, Source Apportionment and Health Risk Assessment

The composition of atmospheric aerosols can help to identify pollution sources, particulate transportation and possible impacts on human health. In this study, seasonal variations and sources of elemental contents in PM10 from Faisalabad area were investigated. In total 117 samples were collected on 24 hours basis from September 2015 to December 2016. The selected trace elements, viz., Al, Ba, Ca, Fe, K, Mg, Mn, Na, P, Pb, S and Zn were measured by inductively coupled plasma optical emission spectrometry (ICP-OES). The average PM10 concentration was found to be 744 � 392 μg m-3, exceeding the limits proposed by Pak-EPA (150 μg m-3), US-EPA (150 μg m-3) and WHO (50 μg m-3). On average concentration basis, the elements were in the order of Ca ] Al ] S ] Fe ] K ] Mg ] Zn ] Na ] Pb ] P ] Mn ] Ba. The elements apparently emitted from natural sources were dominant in spring and summer seasons, while those emitted from anthropogenic inputs were more prominent in winter and autumn seasons. A correlation analysis revealed that pairs of elements originated from common sources were suspended in the ambient air. The enrichment factors (EFs), principal component analysis (PCA) and cluster analysis (CA) indicated wind-blown dust, biomass burning, fossil fuel combustion and vehicular exhaust/non-exhaust emissions as major sources. A health risk caused by non-carcinogenic trace elements such as Pb, Zn and Mn was also assessed according to the method specified by US-EPA.