Characterization of precipitation at Agra

In the present study, the precipitation at Agra city was studied during July-September, 1991. Thirty two samples were collected at Dayalbagh which is a suburban area in the NW of the city with no major industrial activities and minimum traffic density. The study comprised the determination of F, Ci, NO3, SO4, Na, K, Ca, Mg, NH4, Fe, Cu, Zn, and SiO2 in the wet-only samples. On the basis of the neutralizing factors and correlations, it has been determined that in our region, acid neutralization is brought about by calcium rather than the ammonium ion. The Ca/K and Ca/Mg ratios indicated that only 10 percentile of the values in the rainwater samples correspond to local soil and the rest could be attributed to transported soil. The data were also subjected to factor analysis based on principal component analysis, using the SPSS software. The rotated factor matrix grouped the variables into four factors. The first factor includes Cu, Zn, Fe and Na which may be attributed to industrial activities and scavenging processes. Factor 2 clusters Ca, HCO3, NO3, SO4, Cl and Mg together, all of which are soil-derived species. Factor 3 groups K and NH4 which may be attributed to biogenic combustion emissions. Factor 4 includes F and SiO2 which are probably because of their emission in the process of lime pulverization. Copyright (C) 1996 Elsevier Science Ltd