Sulfate Sources in Carbonaceous Aerosol Particles in the Urban Atmosphere: The Case of Irkutsk

According to monitoring data, it is found that the main source of sulfates in carbonaceous particles in the atmosphere of Irkutsk is sulfur dioxide captured from the air. Their accumulation in the particles is caused by heterogeneous chemical reactions (HCRs) and is accompanied by the substitution of hydrocarbonates ( $${\text{HCO}}_{3}^{ - }$$ ) for sulfate anions. In this case, sulfur dioxide is oxidized by ozone in the dry atmosphere, and hydrogen peroxide (H2O2), along with dissolved ozone, also participates in the oxidation process in the moist atmosphere. The details of the mechanisms for these HСRs are discussed and the estimates of the dynamics of sulphate production in carbonaceous particles are indicated.