TRENDS OF ATMOSPHERIC FINE AND COARSE PARTICULATES IN KUALA-LUMPUR, MALAYSIA (1986-1990)

Daily samples of atmospheric fine particulates (FP; particle less-than -or-equal-to 2.5 mum diameter) and coarse particulates (CP; 2.5-10 mum diameter) were collected by a dichotomous sampler sited at the Univer siti Tecknologi Malaysia, Kuala Lumpur. Results are presented form a f ive year duration monitoring programme carried out from October 1986 t o December 1990. These results show that the FP mass concentration is twice the CP concentration and constitutes approximately 70% of the in halable particulate (IP) matter at the site (IP=FP+CP). The seasonal v ariations of FP, CP and IP particulate concentrations were consistent throughout the sampling period, with the coefficient of variation of p articulate concentration varying between 22% and 122%. A marked season al variation in particulate concentration was observed, concentration being highest during dry periods and lowest in the wet periods of the year, with a decrease of 8% to 32% in the particulate mass concentrati ons compared to the average concentration over the study period. The e levated concentrations of fine particulates observed during local haze episodes suggest that this fraction contributes significantly to the haze phenomenon. The CP concentration showed a declining trend of 41% from 1986 to 1990, but no significant trend for FP was observed at the site. The increasing trend of FP/CP ratio (100% increment over this p eriod) reveals an increasing dominance of fine particulates in the reg ion.