Spatial and Temporal Distribution of Near-Surface Aerosol Concentration as a Factor of Diversity of Living Conditions in a Megapolis

Abstract

The work examines the spatial (over megapolis territory) and temporal (interannual, seasonal, and daily) variability of the near-surface aerosol mass concentration in Moscow atmosphere during 2020–2023. The data on continuous monitoring of PM₁₀ and PM_2.5 concentration at the stations of State Budgetary Institution “Mosecomonitoring” and at the city observation point of A.M. Obukhov Institute of Atmospheric Physics Russian Academy of Sciences, were analyzed. The station location in various megapolis microdistricts with different urban conditions (relief, density of buildings, intensity of highways, availability of green areas, wind regime, and so on) determine the efficiency of accumulation/dispersion of atmospheric impurities. The annual concentrations of PM₁₀ and PM_2.5 at the “cleanest” and “dirtiest” measuring stations can differ by two times or more. The monthly maximal PM₁₀ concentrations are at all stations in March-April, when daily values can exceed the MPC (60 µg/m³) at the most “dirty” stations. The interannual, seasonal, and daily variability of PM_2.5 and PM₁₀ concentrations are determined by synoptic and meteorological conditions, characteristics of the underlying surface, and intensity of local anthropogenic sources. Urban conditions determine the amplitude of daily fluctuations and can also contribute to the temporary shifts and fuzzing of concentration extreme points in time fluctuations. In Moscow, the episodes of extremely high aerosol air pollution are associated with regional or long-range atmospheric transport of dust and/or smoke aerosols from other regions. These phenomena cause atypical aerosol concentration maxima in different months. Our results can be useful for assessing a variety of living conditions in the megapolis in terms of aerosol air pollution, as well as for analyzing and predicting the state of ecosystems and the climate of Moscow.