Seasonal air quality profile of inorganic ionic composition of PM10 near Taj Mahal in Agra, India

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 (PM10) is not characterized so far particularly in a historical and world heritage city like Agra. This study presents seasonal variation in mass levels of PM10 and its ionic composition. PM10 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 PM10 mass level varies from 115 to 233, 155 to 321, and 33 to 178 mu g/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 mu g/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 NH4 (+) to nonsea salt SO4 (2-) and NO3 (-) and aCations to aAnios 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 PM10 and also to know the characteristics of PM in background areas for better understanding of the emission sources.