Micromineral Composition and Morphology of Near-surface Dust Aerosol in a Megapolis in Winter

Abstract

The morphology and composition of aerosol particles determine their activity in atmospheric heterogeneous processes and affect the radiation and chemical properties of the atmosphere. However, there is still insufficient information about the morphological characteristics of atmospheric aerosols. This work studies mineral composition of dust aerosol particles and identify natural and anthropogenic components in aerosol composition in the surface air layer in Moscow metropolis in winter. Microparticles containing a lot of potentially toxic elements, such as heavy metals and metalloids of anthropogenic or mixed origin, were found. Several groups of metal-containing microparticles in near-surface aerosols were identified, the most common of which were: (1) sulfates (mainly Ba and Sr); (2) sulfides (Fe, Sb, and Pb); (3) oxides (Fe, W, Cu, As, Cd, and Pb); (4) intermetallides (Pb–Sn–Zn, Pb–Zn, Cu–Zn, Cu–Pb, Te–Sb–Al–Bi, and Fe–Ni–Cu–Sn–Fe–Cr–Ni); (5) native metals (Pb, Zn, Ni, Te, Fe, Zr, and W). The distributions of different elements over the surface of a filter with an aerosol sample was estimated. It was found that most of microminerals in dust particles were in the calcium phase, and to a lesser extent, in silicate and aluminosilicate phases. The results complement information on the morphology and micro-mineral composition of aerosols in the near-surface air of a megalopolis and can be useful both for clarifying the role of aerosol particles in atmospheric heterogenic processes which change the climate and for solving applied environmental problems.