Plenary Lecture 4

Air quality in Kuala Lumpur, Malaysia, has been associated with various natural and anthropogenic sources and meteorological conditions. Air pollutants that show seasonal variations and frequently exceed the Malaysia Ambient Air Quality Standard (MAAQS) are particulate matter (PM) and surface ozone (O 3 ), predominantly related to the monsoon seasons. Other air pollutants such as volatile organic compounds (VOCs), namely benzene, toluene, ethylene, and xylene (BTEX), were found to be recorded at the highest concentration near roadsides. usually associated with daily activities, particularly related to the number of motor vehicles on roads, industrial activities and combustion processes. Combustion from biomass burning during haze episodes increased the concentration of carcinogenic substances such as polycyclic aromatic hydrocarbons (PAHs). Several inorganic PM 2.5 compositions, such as sulfate and potassium, and organic molecules, such as levoglucosan (1,6-anhidro-β-D-glucopyranose), have been identified as indicators for biomass burning. Our latest study on persistent organic pollutants, polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in Kuala Lumpur shows that the Ʃ17PCDD/PCDF concentration in ambient air was 736 ± 375 fg WHO-TEQ m -3 , whereas PM 2.5 , TSP, and gaseous phase concentrations were 223 ± 161 fg WHO-TEQ m -3 , 337 ± 213 fg WHO-TEQ m -3 and 507 ± 273 fg WHO-TEQ m -3 , respectively. Exposure to the gaseous phase of Ʃ 17 PCDDs/PCDFs resulted in a greater inhalation lifetime cancer risk (1.58E06-5.28E-06) than exposure to the particulate phases of TSP (9.1E-07-3.0E-06) and PM 2.5 (6.98E-07-2.33E-06).