Atmospheric dust loads and their elemental composition at a background site in India

Air particulate samples collected during 1995-96 at a background site situa ted on the east coast of Thar Desert in Rajsthan State of India were analys ed for atmospheric dust loads (Suspended Particulate Matter) and elemental composition. The values of SPM ranged from 9 mug M-3 to 97 mug M-3 with an average of 43 mug M-3 except a few episodic values, which were 3 to 5 times higher than the average during summer months. The results for elemental co mposition of the particulate samples showed that the concentrations of anth ropogenic toxic trace elements viz. Br, Cr, Pb, Sb, Se and Zn are lower by a factor of 2 to 10 as compared to urban areas. The high enrichment factors for anthropogenic elements viz. Br, Pb, Sb and Zn show an input from coal/ wood fuel burning and vehicular pollution at the sampling site. The depleti on of Si in SPM samples shows long distance transport of dust to the sampli ng site.