SCATTERING AND ABSORPTION-COEFFICIENTS VS. CHEMICAL-COMPOSITION OF FINE ATMOSPHERIC AEROSOL-PARTICLES UNDER REGIONAL CONDITIONS IN HUNGARY

The light scattering and absorption coefficients of aerosol particles with a dry diameter below 1 mu m were recorded in the country air of H ungary. Concentrations of different inorganic and organic ions were me asured in parallel to estimate the nature of particles causing light s cattering. The sample air was heated gently to maintain a relative hum idity of 30% and coarse particles were removed by a multi-jet impactor . The aerosol light scattering coefficient was monitored with an integ rating nephelometer, while absorption was measured on the basis of the rate of blackening of a filter. Results gained during two time period s, mostly in the winter months, are presented in this paper. Data show that the winter average light scattering coefficient is 93 Mm(-1), wh ile the corresponding figure for light absorption is 8.9 Mm(-1). This results in a single-scatter albedo of 0.91. Comparison of the optical data with chemical information indicates that there is a good correlat ion between light scattering coefficient and sulfate concentration. Th e relationship is significant, in particular, in the winter half-year. Regression calculations among the measured parameters suggest for sum mer and winter half-year a sulfate mass scattering efficiency of 6 and 8 m(2) g(-1), respectively. By using a mass absorption efficiency of 10 m(2)g(-1), the average winter absorption coefficient corresponds to an elemental carbon concentration of 0.9 mu g m(-3). (C) 1998 Elsevie r Science Ltd. All rights reserved.