CHARACTERIZATION OF CHEMICAL-SPECIES IN PM2.5 AND PM10 AEROSOLS IN BRISBANE, AUSTRALIA

Aerosol samples for PM10(particulate matter with aerodynamic diameters less than 10 mu m) were collected from September 1993 to August 1994 at five sites representing the major land use patterns in Brisbane, a subtropical coastal city in Australia. The samples collected were anal ysed by techniques such as ion beam analysis and the integrating plate laser absorption method, and the chemical composition of the samples was reconstructed from the observed elemental composition. For these P M10 samples, the major components, on average, were crustal matter (25 % by mass), organics (17%), sea salt (12%), elemental carbon (10%) and ammonium sulphate (7%). Aerosol samples of PM2.5 (particulate matter with aerodynamic diameter less than 2.5 mu m) were collected by a dich otomous sampler at one of the sites (GU), a site on university buildin gs located in a suburban area of Brisbane but surrounded by a buffer z one provided by a forest conservation area. A high average fine Br/Pb ratio of 0.36 in the GU samples, which is close to that in vehicle exh austs, indicates that this site probably has low background levels of lead even though there has been significant traffic in the area for 20 years, so the forest area is an effective buffer to road dust from th e surrounding suburbia. Temporal trends at this site suggest that road side dust and industry-sourced crustal matter could contribute to mor e than half of the mass of crustal matter. Seasonal meteorological con ditions which determine the dispersion of pollutants out of Brisbane a nd the continuous input of rural dust into Brisbane are potentially im portant factors influencing the level of crustal matter in Brisbane. H owever, major rural dust events do not considerably increase the seaso nal average level of crustal matter. Also, apart from significant loca l influences at some sites (such as heavy road traffic network or a ce ment factory), the results from the GU site show a similar level of el emental and chemical components from anthropogenic sources to sites in heavy industrial and commercial/light industrial sites, indicating th at most anthropogenic emissions are evenly and widely distributed in B risbane. (C) 1997 Elsevier Science Ltd.