Dry deposition of sulphate and nitrate to polypropylene surfaces in a semi-arid area of India

Dry deposition rates of the major ionic species Cl −, NO 3 −, SO 4 2−, Na +, K +, Ca 2+ and Mg 2+ were estimated by the surrogate collection technique using polypropylene surfaces. The dry deposition rates of the soil derived cations Ca 2+, Na +, K + and Mg 2+ were of the order of 0.4–6.1 mg m −2 d −1. The dry deposition rates of the acidic ions NO 3 − and SO 4 2− were of similar magnitude, suggesting that they are also soil derived or associated with the soil elements. On a seasonal basis, deposition rates were maximum during the winter followed by summer and minimum during the monsoon.