TRENDS IN BACKGROUND AIR-POLLUTION PARAMETERS OVER INDIA

The Background Air Pollution Monitoring Network (BAPMoN) data from ten stations in the Indian region for the period 1973-90, has been used t o determine the background trends. Falling pH and increasing turbidity trends have been noticed in all but one of the stations. The post 198 2 epoch has witnessed fall in annual mean pH at Vishakhapatnam, Allaha bad, Pune and Nagpur though the reduction of mean values are not stati stically significant at 5% level of confidence. Frequency distribution s of the values of turbidity coefficient B(500 nm) for the epochs 1974 -80, 1981-85 and 1986-90 are also presented here. The trend of atmosph eric burden is seen to be positive upto the second epoch and stable su bsequently. The source identification for chemical constituents of rai nwater has been examined by carrying out principal component analysis and using BAPMoN rain chemistry data collected in the entire period of 1974-1988. Copyright (C) 1996 Published by Elsevier Science Ltd