Measurements of dry deposition of gaseous and particulate sulphur on marble at a suburban site

摘要

Dry deposition of S (sulphur) as sulphate on white marble (natural surfaces) has been measured at Dayalbagh, a suburban site of semi-arid region of India, in winter season (December 1999-March 2000). Samples were collected by exposing the white marble for 24 h and analyzed by Dionex Dx-500 Ion Chromatograph system. Atmospheric concentration of SO_2 was 7.8 +- 2.0 μg m~(-3) and particulate sulphate was 7.9 +- 1.8 μg m~(-3). The dry deposition of S as sulphate has been found to be 0.19 +- 0.12 mg m~(-2) h~(-1). The percentage contribution of the particulate sulphate (78.9) was higher than that of gas phase (21.1). The calculated dry deposition velocity (Vd) of particulate sulphate has been found to be 0.53 +- 0.27 cm s~(-1). The V_d calculated by present method is lower than that reported by throughfall method, while V_d range is comparable to other methods like foliar extraction, micrometeorological and surrogate methods.