769 ISSN 0001-4338, Izvestiya, Atmospheric and Oceanic Physics, 2016, Vol. 52, No. 8, pp. 769–783. © Pleiades Publishing, Ltd., 2016. Original Russian Text © M.S. Artamonova, D.P. Gubanova, M.A. Iordanskii, V.A. Lebedev, L.O. Maksimenkov, V.M. Minashkin, Y.I. Obvintsev, O.G. Chketiani, 2016, published in Geofizicheskie Protsessy i Biosfera, 2016, Vol. 15, No. 1, pp. 5–24. Variations of the Aerosol Concentration and Chemical Composition over the Arid Steppe Zone of Southern Russia in Summer M. S. Artamonova a, *, D. P. Gubanova b, **, M. A. Iordanskii b, ***, V. A. Lebedev b, ****, L. O. Maksimenkov a, *****, V. M. Minashkin b, ******, Y. I. Obvintsev b, *******, and O. G. Chketiani a, c, ******** a Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, Moscow, Russia b AO Karpov Institute of Physical Chemistry, State Corporation Rosatom, Moscow, Russia c Space Research Institute, Russian Academy of Sciences, Moscow, Russia *e-mail: artamonova@ifaran.ru **e-mail: dgubanova@mail.ru ***e-mail: miordan@mail.ru ****e-mail: triak@inbox.ru *****e-mail: maksimenkov@ifaran.ru ******e-mail: vminash@yandex.ru *******e-mail: obvintyu@mail.ru ********e-mail: ochkheti@gmail.com Abstract⎯Variations in the surface aerosol over the arid steppe zone of Southern Russia have been measured. The parameters of atmospheric aerosol (mass concentration, both dispersed and elemental compositions) and meteorological parameters were measured in Tsimlaynsk raion (Rostov oblast). The chemical composi- tion of aerosol particles in the atmospheric surface layer has been determined, and the coefficients of enrich- ment of elements with respect to clarkes in the Earth’s crust have been calculated. It is shown that, in summer, arid aerosols are transported from both alkaline and sandy soils of Kalmykia to the air basin over the obser- vation zone. Aerosol particles in the surface air layer over this region have been found to contain the products of combustion of oil, coal, and ethylized fuel. These combustion products make a small contribution to the total mass concentration of atmospheric aerosol; however, they are most hazardous to the health of people because of their sizes and heavy-metal contents. A high concentration of submicron sulfur-containing aerosol particles of chemocondensation nature has been recorded. Sources of aerosol of both natural and anthropo- genic origins in southern Russia are discussed. Keywords: aerosol pollution, mass concentration, dispersed and elemental compositions, transport, steppe zone DOI: 10.1134/S000143381608003X INTRODUCTION Atmospheric aerosol is an extremely important atmospheric component that strongly affects the bio- sphere and climate. It is a dynamic system, unique in its qualities, and characterized by the spatiotemporal variability of its physical and chemical parameters (Ivlev, 1982; Kondratyev et al., 1983; Seinfeld and Pandis, 2006). Having a large surface, atmospheric aerosol particles can serve as catalyzers for heterogenic processes; be effective sorbents of trace-gas atmo- spheric components; and, due to their physical prop- erties (size, opacity, and density), impact the radiative balance and the Earth’s climate (Aerosol and climate, 1991; Qin et al., 2014). In recent years, due to the increase in environmen- tal pressure, changes in the Earth’s climate and the intensification of related problems, the study of the atmosphere’s composition is becoming ever more important. The study of the physicochemical proper- ties and the structure and sources of atmospheric aerosols causes additional interest. However, the role of aerosols in the ecosystem is still undervalued. Being one of the most common and strongest pol- luters of the atmosphere, aerosol largely contributes to the evolution of the ecosystems of regions that are most vulnerable and prone to ecological strain as a result of their natural, geographic, and climatic fea- tures. Arid steppe regions on the South of the Russian Federation are examples of such regions. As is known, arid regions are one of the main sources of aerosol that enters the atmosphere during both dust storms and dry, hot weather (Kondratyev et al., 1983; Soviet- American…, 1993; Andronova et al., 1998; Golitsin et al., 1998; Gorchakov et al., 1998; Gledzer et al.,