SEM-EDX Characterization of Individual Coarse Particles in Agra, India

Aerosol samples were collected during winter and summer season in Agra, India. The mass concentrations of TSP ranged from 206.1-380.5 mu g/m(3) with the average concentration of 306.1 mu g/m(3). The seasonal average concentrations of TSP were 273.4 +/- 85.5 mu g/m3 in summer and 338.6 +/- 89.1 mu g/m(3) in winter. The high levels of mass concentration during winter may be attributed to different emission sources and meteorological conditions at this time of year. The morphology, size and elemental composition of individual aerosol particles were examined using a scanning electron microscope (SEM) coupled with an energy dispersive X-ray system (EDX). The particles analyzed in the study were mostly of large size, with equivalent diameters ranging from 2 to 70 mu m. Based on the results of the elemental composition and morphology, 3,500 particles were classified into three groups: biogenic aerosol, geogenic and anthropogenic particles. Different groups of particles have varied morphologies. The soil related aerosols were dominant during the sampling period, showing that crustal materials are the primary contributor to airborne particles at this site. A distinct seasonal variation in the amount of carbonaceous particles was observed. The significant increase in mineral dust particles found during summer may be attributed to the contribution of dust storms, which is also supported by a trajectory cluster analysis.