Light Degrading Properties of Size-Fractionated PM10 Aerosol Samples Collected from an Industrial Area in Brisbane, Australia

Thirty-seven days of PM 10 aerosol samples (particles with aerodynamic diameter <10 w m) were collected in an industrial area in Brisbane during April to June 1999 to study the light extinction efficiencies of urban aerosols in different size ranges. The light scattering coefficient of the air was measured by nephelometry. The light absorption coefficient of the aerosol samples was measured by the integrating plate laser absorption method. Multiple linear regression techniques were used to investigate the relationships between the visibility degrading properties and the chemical composition of the aerosol samples. The results are comparable with those from other visual air quality studies. The absorption of light by fine (PM 2.5 ) aerosols is mainly due to elemental carbon (EC) particles smaller than 0.5 w m. The b 0 ap values of EC particles in different size ranges are 9.08 (< 2.7 w m) and 0.32 (2.7-10 w m)m 2 g -1 , respectively. The absorption of light by coarse (PM 2.5-10 ) aerosols is mainly due to ...