URBAN AND RURAL BULK PRECIPITATION CHEMISTRY IN BANGALORE REGION

摘要

Bulk precipitation is a combination of wet precipitation and dry fallout, which was compared at an urban Bangalore site and nearby rural areas in order to examine the influence of emissions within a large urban area on local precipitation chemistry. During the study period, samples were collected from June to September 2005 on weekly basis and analysed for pH, conductivity, major cat ions (Ca~(2+), Mg~(2+). Na~+, K~+, NH_4~+) and anions (Cl~-, SO_4~2, HCO_3,~-, NO_ 3~-, NO_2~-, PO_4~(3-)). Rural precipitation chemistry of Bangalore region in which the suburban site was upwind of the urban site and most urban emissions may be affected. Precipitation quality is a function of its contents of both acids and bases (alkaline), and any attempt to understand the processes causing acid precipitation must deal with the potential acid neutralizing capacity of alkaline materials. The objective of the present study is to establish the chemical composition of bulk precipitation samples collected from rural precipitation of Bangalore region and to assess variability in concentration between the areas. Attempt has been made to identify the predominant ions, which decide the quality of rain. It revealed that acidic pH of bulk precipitation samples were caused by H_2SO_4.