Dust Aerosol from the Northern Caspian Sea Regions in Near-Surface Air in the Center of European Russia

Abstract Dust aerosol from the regions of sandstorms is transported by air masses to thousands of kilometers, affecting the optical properties of the atmosphere, climate, and terrestrial natural objects. The northern Caspian region (Kalmykia, the Volga Delta, the Transcaspian lowlands, and northwestern Kazakhstan) is a year-round source of dust aerosol. Based on the data of Mosecomonitoring stations for 2011–2021 we analyzed the episodes of an increase in the level of aerosol pollution in Moscow near-surface air associated with long-range atmospheric transport of dust from the Caspian region. Eight months (about 6%) with the daily PM 10 concentration in Moscow higher than MPC value during 3 or more days were revealed. The duration of each episode ranged from 3 to 10 days, and as a total they did not exceed 9% of days per year on average. During those episodes the maximal daily PM 10 concentration in the near-surface Moscow air was 2.7 ± 1.1 times higher than the corresponding monthly values. The months with episodes of long-range atmospheric dust transport to Moscow are characterized by 1.9 ± 2.0°C higher air temperature and by 9 ± 13 mm lower precipitation amount relative to the corresponding norms for Moscow.