摘要：Long-term monitoring of near-ground ozone concentration was performed in the remote mountain area as well as at rural and urban sites of South-East Siberia. Ozone concentrations at all three sites had similar seasonal dynamics with its maximum in spring and minimum in autumn. Such seasonal trends were characteristic of many areas of the Northern Hemisphere. Diurnal fluctuations of ozone concentrations were caused by photochemical generation of ozone at daytime and its partial depletion at night. Diurnal fluctuations were maximal in spring and summer and minimal in December and January in accordance with solar radiation intensity. At the urban site, mean ozone concentrations were significantly lower (about 2 times) than those in the rural and background areas. This was likely attributed to the increased consumption of ozone for oxidation of air pollutants in the urbanized area. A tendency to the decrease of mean annual ozone concentrations was recorded during long-term observations at the mountain site Mondy.
