Forest fires in Irkutsk region as a possible source of benz(a)pyrene in the atmosphere of Bratsk

The aim of the study is to analyze wildfires in Irkutsk region and its districts in 2014-2020 as a possible source of benz(a)pyrene pollution of the atmospheric air in Bratsk. The dynamics of the number, the area of fires and their dependence on each other is explored. A comparative assessment of fires in the Bratsk district, Bratsk and its surrounding districts, and in Irkutsk region was carried out. The dynamics of reducing atmospheric air pollution with benz(a)pyrene in Bratsk during the study and the level of average carcinogen content in the atmosphere of 16 cities of the region was explored. Positive trends and linear dependences of the average annual and maximum monthly concentrations of benz(a)pyrene in the atmospheric air of Bratsk on the indicators of wildfires in the Bratsk district, a group of districts and in the entire region were found. A regular increase in the accuracy of the correlation between the content of benzo(a)pyrene in the atmosphere of Bratsk and the indicators of fires in a number of territories from Irkutsk region to Bratsk district was shown. Higher correlation coefficients were found for indicators of average annual concentrations of benzo(a)pyrene and for the number of fires compared, respectively, with maximum average monthly concentrations and indicators of natural burned areas. The average concentration of benzo(a)pyrene in the atmosphere of 16 cities did not depend on the indicators of fires in Irkutsk region. A conclusion is made about possible consequences of wildfires for air pollution in Bratsk with carcinogenic benzo(a)pyrene.