Chemical composition of atmospheric aerosols between Moscow and Vladivostok

S. Kuokka (1) , K. Teinilä (1) , K. Saarnio (1) , M. Aurela (1) , M. Sillanpää (1) , R. Hillamo (1) , V.-M. Kerminen (1) , E. Vartiainen (2) , M. Kulmala (2) , A. I. Skorokhod (3) , N. F. Elansky (3) , I. B. Belikov (3)

1 FMI - Finnish Meteorological Institute
2 Helsingin yliopisto = Helsingfors universitet = University of Helsinki
3 IAP - A.M.Obukhov Institute of Atmospheric Physics

The TROICA-9 expedition (Trans-Siberian Observations Into the Chemistry of the Atmosphere) was carried out at the Trans-Siberian railway between Moscow and Vladivostok in October 2005. Measurements of aerosol physical and chemical properties were made from an observatory carriage connected to a passenger train. Black carbon (BC) concentrations in fine particles (PM_2.5, aerodynamic diameter <2.5 ?m) were measured with an aethalometer using a five-minute time resolution. Concentrations of inorganic ions and some organic compounds (Cl^?, NO₃^?, SO₄^2?, Na⁺, NH₄⁺, K⁺, Ca²⁺, Mg²⁺, oxalate and methane sulphonate) were measured continuously by using an on-line system with a 15-min time resolution. In addition, particle volume size distributions were determined for particles in the diameter range 3?850 nm using a 10-min. time resolution. The continuous measurements were completed with 24-h. PM_2.5 filter samples which were stored in a refrigerator and later analyzed in chemical laboratory. The analyses included mass concentrations of PM_2.5, ions, monosaccharide anhydrides (levoglucosan, galactosan and mannosan) and trace elements (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sb, V and Zn). The mass concentrations of PM_2.5 varied in the range of 4.3?34.8 ?g m^?3 with an average of 21.6 ?g m^?3. Fine particle mass consisted mainly of BC (average 27.6%), SO₄^2? (13.0%), NH₄⁺ (4.1%), and NO₃^? (1.4%). One of the major constituents was obviously also organic carbon which was not determined. The contribution of BC was high compared with other studies made in Europe and Asia. High concentrations of ions, BC and particle volume were observed between Moscow and roughly 4000 km east of it, as well as close to Vladivostok, primarily due to local anthropogenic sources. In the natural background area between 4000 and 7200 km distance from Moscow, observed concentrations were low, even though there were local particle sources, such as forest fires, that increased occasionally concentrations. The measurements indicated that during forest fire episodes, most of the aerosol mass consisted of organic particulate matter. Concentrations of biomass burning tracers levoglucosan, oxalate and potassium were elevated close to the forest fire areas observed by the MODIS satellite. The polluted air masses from Asia seem to have significant influences on the concentration levels of fine particles over south-eastern Russia.

Domaines: Océan, Atmosphère

S. Kuokka, K. Teinilä, K. Saarnio, M. Aurela, M. Sillanpää, et al.. Chemical composition of atmospheric aerosols between Moscow and Vladivostok. Atmospheric Chemistry and Physics Discussions, 2007, 7 (3), pp.7473-7508. ⟨hal-00302827⟩