Chemical composition and microphysical characteristics of atmospheric aerosol over moscow and its vicinity in June 2009 and during the fire peak of 2010

The microphysical characteristics of aerosol were measured in the atmospheric surface layer simultaneously over the center of Moscow and its vicinity (Zvenigorod Scientific Station, Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences) from June 15 to June 30, 2009, in order to compare the mass concentrations, particle-size distribution functions, and elemental compositions of aerosol over the megapolis and the background zone. During the fire peak of 2010, on August 8, aerosol samples were taken in the center of Moscow and their chemical composition was determined. Comparing results obtained from the simultaneous measurements of the concentrations of aerosol and its elemental composition made it possible to determine their interdiurnal variability, which suggests that the features of time variations are of a regional character and they are determined mainly by the dynamics of the synoptical processes of air-mass exchange. The chemical composition of obtained samples was determined using the method of atomic absorption spectrometry. The measurement results obtained in June 2009 revealed an increase in the content of anthropogenic elements in the atmosphere over Moscow when compared to their content in the atmosphere over the background zone. In Moscow, during the summer fires of 2010, the concentration of sulfur exceeded its concentration in June 2009 by an order of magnitude, and the concentrations of Na, Mg, Al, Si, K, Ca, and Fe increased several times. The mean mass concentration of aerosol amounted to 917 μg/m³ in August 2010 and 50–70 μg/m³ in June 2009.