Composition of rain water in Agra city, a semi-arid area in India

49-55Rainwater samples were collected at St. John's crossing during the monsoon period of 2000. The cations (Ca2+, Mg2+,Na+, K+ and NH4+) and anions (F¯, Cl¯, HCO3¯, NO3¯ and SO42¯) along with pH were measured. The percentage contribution of soil components (Ca2+, Mg2+,Na+, K+) and NH4+ are observed to be higher than the acidic substances. The ratio of F¯/ Ca2+, Mg2+/ Ca2+, Na+/ Ca2+ and NO3¯/ Ca2+ in rainwater samples indicates that local soil plays a significant role in precipitation chemistry. Hence, soil dust is responsible for neutralization of wet deposition. The data were also subjected to factor analysis based on principal component analysis using the SPSS software. Factor analysis also indicates that the soil as well as dust emission is the major contributor to rainwater composition