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Influence of meteorological conditions on explosive increase in O3 concentration in troposphere

Wang, Jizhi, Yang, Yuanqin, Zhang, Yangmei, Niu, Tao, Jiang, Xiaofei, Wang, Yaqiang, Che, Huizheng
The Science of the total environment 2019 v.652 pp. 1228-1241
air, basins, meteorological parameters, mixing, nitrogen dioxide, ozone, pollutants, pollution, river deltas, rivers, troposphere, China
Ozone (O3) pollution in the troposphere, especially at the surface layer, has become a focus of attention in recent years. High O3 concentration events tend to occur frequently in north China, Yangtze, the Pearl River Delta, and the Sichuan Basin, among others. Studies on the meteorological contribution to O3 in the troposphere have become a new direction for the scientific community. This research intends to explore how meteorological conditions contribute to O3 pollution in all seasons on the basis of further studies of the PLAM index. Our findings are as follows. (1) In pollution-sensitive areas, following a height uplift in the pollution mixing layer (H_PML), NO2 concentration decreases initially, followed by an explosive increase (EI) in O3 concentration after sunrise. (2) This process varies significantly by season and area. (3) According to an analysis of the meteorological conditions causing rises in O3 concentration within a few hours after sunrise, the initial decrease–subsequent increase in NO2 versus O3 concentration satisfies the law of exponent power rule, according to which seasonal and regional differences in coastal and inland areas depend on coefficients α and β. The explosive increase in O3 concentration, decrease in NO2 concentration, and characteristics of their diurnal cycles are also discussed. (4) Under the meteorological condition of static stability, below the static and stable cover, the H_PML of the polluted mixed layer consistently indicates the reciprocating cycle of day uplift and night pressure. The effect of air pump suction on the pollutant is an important mechanism of large-scale pollution in the study area under the condition of static and stable cover. (5) The influencing mechanism of meteorological conditions in the diurnal H_PML cycle aids in improving the understanding of O3 concentration increases in the troposphere.