PARAMETRIC STUDY OF SELECTIVE REMOVAL OF ATMOSPHERIC AEROSOL BY BELOW-CLOUD SCAVENGING

This work studies the scavenging efficiencies of aerosol particles after a given rain regime as a function of time by below-cloud scavenging. We also analyse the health impact of aerosol before and after rain by comparing the respirable dust fractions. The well-known equations of below-cloud scavenging are applied to three atmospheric conditions (clear, hazy and urban) in two precipitation regimes (drizzle and heavy rain) with four different drop size distributions (DSDs) in each case. From this study it is inferred that respirable dust is hardly scavenged by rain, and DSDs have minor importance in each rain regime in the results. As compared with the volume of respirable aerosol before rain, it remains roughly 60% after 12 h of drizzle and after 1 h of heavy rain.