Submicron aerosol and nitrogen dioxide in the atmospheric near-surface layer at the Zvenigorod Scientific Station of the A. M. Obukhov Institute of Atmospheric Physics RAS: Thirty years of measurements

The paper presents results of measurements and trend analysis of the mass concentration of submicron aerosol and the NO2 content in the atmospheric surface layer at the Zvenigorod Scientific Station of the A. M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences. The station is located in a rural area of the western Moscow region. Aerosol concentration is determined by directional light scattering in a flow nephelometer. The NO2 content is measured spectrometrically by zenith-scattered solar radiation. Three decades of aerosol and NO2 measurements give a possibility to analyze long-term trends in near-surface aerosol and NO2. Seasonally dependent estimates of the aerosol trends are presented for three periods differing in character of aerosol variability: 1991–2002, 2003–2012, and 2013–2020. The common feature of the trends is a general decrease in the aerosol concentration. There are however significant interdecadal differences in the strength of the trends and in their seasonal dependence. The NO2 content in the near-surface layer undergoes a significant positive trend. The NO2 increase is likely associated with an increase in the population and human activity resulting, in particular, in the increase in motor traffic in the region. Effects of wind direction on aerosol and NO2 anomalies are also studied.