Abstract
Air pollution is a major challenge facing many cities around the world. Particulate matter especially the inhalable category, PM2.5 is of most concern as it affects health and the environment gravely. In this study spatial distribution of PM2.5 in and around Jeddah city was studied through sampling from three locations representing an inner-city site, a background site, and an industrial site. Samples were collected using low volume dichotomous samplers and analyzed for elements water soluble inorganic ions, and carbonaceous matter. The arithmetic mean of PM2.5 mass concentrations for samples within the city was 37.5 mu g/m(3) while its value was 26 mu g/m(3) at the site in the suburb reflecting the reduced traffic density. Black carbon concentrations at the two city sites averaged 3906 ng/m(3) while the suburban site showed a value of 1387 ng/m(3). A similar trend was observed for ultraviolet absorbing organic compounds (UVPM). Arithmetic means of mass concentrations of water-soluble ions followed the order NO3 > Cl- > NH4+ > SO42- for all three sites. Traffic, long range transport, and road dust resuspension could be the major sources of PM2.5 in the city.