Estimation of urban contribution into variability of the aerosol characteristics in the near-ground atmospheric layer in Tomsk region

Abstract

Abstract The paper presents the results of monitoring the aerosol characteristics in the near-ground layer of the atmosphere at the Aerosol Station of the Institute of Atmospheric Optics of the Siberian Branch of the Russian Academy of Sciences (IOA SB RAS) located at the southeastern outskirts of city of Tomsk and in the background forest area (the Fonovaya Observatory, ∼ 70 km to southwest from Tomsk) in 2014 – 2018. The data were considered on the concentration of aerosol and absorbing substance (soot, black carbon) at two measurement points, as well as the hygroscopic properties of aerosol particles. The features of the annual behavior and interannual variability of the anthropogenic contribution of the city to the average values of aerosol characteristics are analyzed. A significant trend by 7% per year was revealed for an increase in the soot fraction of aerosol under urban conditions. The typical diurnal behavior of the aerosol and soot concentrations at the Aerosol station is characterized by an increase in these parameters at 21-23 hours local time compared to daytime hours. Also a significant decrease in the aerosol hygroscopicity is observed in evening under urban conditions.