The Environmental Health Impact of Respirable Atmospheric Particles (PM2.5) in Hong Kong  

Project Title: The Environmental Health Impact of Respirable Atmospheric Particles (PM2.5) in Hong Kong

Applicant: The Hong Kong University of Science and Technology

Total Approved Grant: $1,170,600 (ECF&WWGF: 50/50)

Duration: 01/01/98 to 31/12/00

Project Status/Remarks: Completed

Scope: To determine the environmental health impact of PM-2.5 by identifying the origin and characterizing the extractable organic and inorganic components and by performing toxicity studies on the extracted organic pollutants; and measuring the rates of wet and dry deposition of the pollutants from the atmosphere at a few selected sites to obtain the fluxes of pollutants from the atmosphere and the residence times of particulate-borne pollutants.

Summary of the Findings/Outcomes:
The inorganic analysis and the solvent extractable organic compound data obtained from the simultaneous TSP and PM2.5 samples and the October 1996 to September 1997 year-long samples indicate that the petroleum-derived alkanes and polycyclic aromatic hydrocarbons are enriched in the less than 2.5 micron cut of the ambient aerosols, while fatty acids are mostly in the larger-than-2.5 micron fraction. Almost 100% of the PAHs are in the finer PM2.5. This suggests that the influence of vehicular exhaust on health can be severe since PAHs are known to be carcinogenic and PM2.5 can penetrate deeper into the lungs. The major source of air pollution in Hong Kong is most likely to be from locally emitted vehicular exhaust with some contributions from the surrounding environment. The high concentration of fatty acids in Hong Kong aerosols are also of concern, since thermally cracked fatty acids such as the exhaust from Chinese stir-frying cooking methods can be toxic and carcinogenic.