Air samples for PM(10) (dp < 10 μm in aerodynamic diameter) were collected from March 2007 to February 2008 near Taj Mahal-a historically sensitive site in Agra. Each sample collected on 20.3 × 25.4-cm Whatman quartz microfiber filter using respirable dust sampler was analyzed gravimetrically for mass concentrations and chemically for elements such as Na, Mg, Al, Si, S, Ca, Sc, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Br, Rb, Cd, Ba, and Pb by inductively coupled plasma atomic emission spectroscopy and inorganic ions such as NH (4) (+) , K(+), SO (4) (2-) , NO (3) (-) , F(-), and Cl(-) by ion chromatograph. Annual average of PM(10) 155.47 ± 77.97 μg/m(3) was three times high the annual average NAAQ standard of 50 μg/m(3) for sensitive area. PM(10) as well as K(+), Cl(-), As, and Pb were higher in winter while crust elements and secondary aerosols were higher in summer. The average equivalent ratio of NH (4) (+) to sum up of SO (4) (2-) and NO (3) (-) was greater than unity which indicates high source strength of ammonia and alkaline nature of aerosols in Agra. Source apportionment of PM(10) was carried out by factor analysis using principal component analysis (varimax rotated factor matrix method) of SPSS. Five sources contributing to PM(10) were identified as crust material, vehicular emissions, industrial emissions, coal and biomass burning, and secondary aerosols.

Atmospheric aerosols and their impacts on the environment particularly on human health is an issue of significant public and governmental concern. Though studies on air quality related to total suspended particulate matter have done by various authors in India, yet respirable suspended particulate matter (PM(10)) is not characterized so far particularly in a historical and world heritage city like Agra. This study presents seasonal variation in mass levels of PM(10) and its ionic composition. PM(10) samples were collected in the proximity of Taj Mahal and subjected to chemical analysis using ion chromatography technique. The preliminary findings reveal that the 24-h average of PM(10) mass level varies from 115 to 233, 155 to 321, and 33 to 178 microg/m(3), respectively, in summer, winter, and rainy seasons indicating critical pollution situation. These values are very much higher than the National Ambient Air Quality Standards of 75 microg/m(3) (prescribed by Central Pollution Control Board, India) in both of summer and winter seasons whereas quite near the permissible limits in rainy season. The equivalent ratios of NH(4)(+) to nonsea salt SO(4)(2-) and NO(3)(-) and summation operatorCations to summation operatorAnios were found to be greater than unity indicating high source strength of ammonia and alkaline nature of aerosols. The study suggests the need for continuous and long-term systematical sampling and detailed physiochemical analysis of PM(10) and also to know the characteristics of PM in background areas for better understanding of the emission sources.

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