Variation of aerosols in relation to some meteorological parameters duringdifferent weather conditions

Variation of aerosol concentration has been studied in the view of some met eorological parameters like wind speed, temperature, relative humidity and rainfall during South-East (SE) monsoon (June-Sept;ember, 1996) and winter (November 1996-February, 1997) at Roorkee. The measurements were done with the help of laser beam scatterometer for a wide range of size of aerosols ( 0.05-3.0 mu m). The present study brings out the fact that the number densi ty of aerosols is very much affected by the meteorological parameters. The aerosol concentration was minimum in the August, September and November, 19 96 and remained around maximum in June-July, 1996 and January-February, 199 7. The variation of aerosols is in phase with relative humidity during wint er season while it is out of phase with temperature. Its variation with rel ative humidity has been explained in terms of condensation taking place in the atmosphere. During monsoon period the rain plays very important role in characterizing the aerosol density. The aerosol concentration and size wer e found to be decreased during September, 1996 although the relative humidi ty was very high. The credit goes to scavenging of aerosol particles.