Particles size distribution of aerosols and associated metals, and source estimation in Delhi, India

INTRODUCTION Human exposure to particulate matter (PM) was determined in Urban Environment of Delhi, India. Samples were collected using eight stages impactor (Marple Cascade Impactor) at five sites during August to October 2011. Three samples were collected from each site; samples were analyzed -3 in eight size ranges gravimetrically and chemically (for metals). Maximum (985 μg m ) exposure to -3 PM was in Okhala an industrial site and minimum (404 μg m ) in Jawaharlal Nehru University, an educational Institute. The human exposure to metals (Cu, Cd, Mn, Pb, Ni, Co, Ca, Mg, K, Fe) at five locations (viz Okhala, Jawaharlal Nehru University, Dhaula Kuan, Hauz Khas and Kaushambi) was considered. It was observed that human exposure was mostly dominated by K, Ca, Mg, Fe and least dominated by Cd, Cu and Co. This study also observed that, Okhala was most polluted area and Jawaharlal Nehru University (forest area, out of industrial and commercial hub) was the least. A significant regression between coarse and super coarse size fraction of total suspended particulate matter was observed. It was also observed that very good correlation exists among 8 metals. Source apportionment was done by principle component Analysis (PCA) of SPSS. Source apportionment by PCA reveals that there are three major sources (crustal re-suspension, industries and trans-boundary movement). Result obtained by PCA shows the dominance of crustal re-suspension. .