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 μm were recorded in the country air of Hungary. Concentrations of different inorganic and organic ions were measured in parallel to estimate the nature of particles causing light scattering. The sample air was heated gently to maintain a relative humidity of 30% and coarse particles were removed by a multi-jet impactor. The aerosol light scattering coefficient was monitored with an integrating nephelometer, while absorption was measured on the basis of the rate of blackening of a filter. Results gained during two time periods, mostly in the winter months, are presented in this paper. Data show that the winter average light scattering coefficient is 93 Mm⁻¹, while 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 correlation between light scattering coefficient and sulfate concentration. The relationship is significant, in particular, in the winter half-year. Regression calculations among the measured parameters suggest for summer and winter half-year a sulfate mass scattering efficiency of 6 and 8 m² g⁻¹, respectively. By using a mass absorption efficiency of 10 m² g⁻¹, the average winter absorption coefficient corresponds to an elemental carbon concentration of 0.9 μg m⁻³.