Moscow smoke haze in October 2014: Variations in gaseous air pollutants

Abstract

The composition of the Moscow atmosphere during the joint smoke screening by near fires in the Moscow region and far forest fires in October 2014 is studied. According to ecological monitoring data, the ratio of mass concentrations of nitrogen oxides and carbon monoxide in “fresh” smokes of near fires reached 0.35; in “old” smokes of far fires, decreased to 0.025. The ratio of the nitrogen oxide concentration to the sum of oxide and dioxide concentrations reached 0.87 in “fresh” smokes” and decreased to zero in “old” ones. It has been shown that statistical characteristics of variations and empirical probability distributions of carbon monoxide and nitrogen oxide concentrations in the smoky Moscow atmosphere in October 2014 radically differ from the corresponding characteristics and empirical distributions in a smokeless atmosphere and during the smoke events in 2002 and 2010. The empirical concentration distribution function for carbon monoxide can be approximated by piecewise exponential functions; for nitrogen oxide, by piecewise power functions. During the smoke event in Moscow in October 2014, a close correlation between the concentration of carbon monoxide and total concentration of nitrogen oxides was observed in a wide range of time scales, which testifies to the joint formation of the abovementioned pollutants during forest fires. The coefficient of the spectral correlation between ozone and nitrogen dioxide concentrations on different time scales varied from +1 to–1, which indicates the complexity of relationships between ozone and nitrogen oxides in a smoky atmosphere.