Abstract:
In summer-autumn 2002, peat bog fires led to the formation of a prolonged large-scale smoke screen in the central district of the Russian Federation. This provoked notable changes in the radiation regime of the atmosphere and worsening of the ecological situation in the region. In July-September 2002, we carried out multidisciplinary studies of the dispersion and chemical composition of smoke aerosol in the surface air layer and atmospheric column. The optical properties of aerosol were measured. The aerosol microstructure and refraction index were determined using methods of light dispersion. It is shown that smoke with low specific absorption is formed during peat bog fires. The single scattering albedo is equal to 0.95-0.98. Two types of smoke formation regime during peat bog fires are distinguished. Along with the narrow (unimodal) particle size distribution, which is typical for the aerosol formed when a biomass burns, comparatively wide (including bimodal) distribution in a radius range of 0.1-0.6 μm is also observed. Peat bog smokes are distinguished by their relatively high condensation activity in the submicrometer-sized aerosol fraction. We determined the element composition of smoke aerosol, including the soot and heavy metal content, which is significantly transformed during the migration of air mass with smoke. Increased concentrations of heavy metals in the smoky atmosphere over Moscow are explained by the impact of urban sources of air pollution. The objective of this work is to study the peculiarities of the microstructure (function of particle size distribution) and absorbing capacity of peat bog smoke.
