Chemical composition of precipitation during 1984–2002 at Pune, India

Since 1984, bulk precipitation samples have been collected at Pune, a tropical urban location in India, in the monsoon season. Data from these studies are used to analyze the long-term trends in the major chemical constituents of precipitation. Significantly increasing trends were observed for SO4 and NO3 which could be attributed to the rise in industrial and vehicular activities during this period. Also Ca, the chief neutralizing constituent, showed decreasing trend, mainly due to the rapid urbanization that reduced the availability of open land which is the major source for Ca. This has resulted in the overall decrease in trend of pH. However, the average pH value is still in the alkaline range due to the dominance of neutralizing potential of precipitation over the acidic potential.