Interactive Effects of the Influencing Factors on the Changes of O3 Concentrations Based on GAMs Model in Chengdu

Abstract

To explore the influence characteristics of the interaction effects between meteorological factors on ozone(O3) concentration in Chengdu, daily air pollutants and meteorological data from 2014 to 2019 were collected. Generalized additive models(GAMs) were adopted to explore the effects of different factors on O3 concentration. The results showed that the relationship between O3 and maximum temperature, sunshine hours, relative humidity, wind speed, precipitation, maximum mixed depth(MMD), and ventilation coefficient(VC) was non-linear. Specifically, the maximum temperature, sunshine hours, MMD, and relative humidity had a significant influence on O3 concentration throughout the year. It is worth noting that the influence of relative humidity and precipitation on O3 concentration during summer was more significant than that for the whole year. In the multi-meteorological factors GAMs of O3 concentration, the meteorological factors mentioned above, except average wind, had significant impacts on O3 concentration change. For the whole year, the judgment coefficient(R2) was 0.849 and the variance explanation rate was 85.1%. The maximum temperature was the most important influencing factor on O3 concentration throughout the year. During summer, corresponding R2 was 0.811 and the explanation rate of variance was 81.3%; however, maximum temperature and MMD were the dominant meteorological factors. In the interaction GAMs, for the whole year, the interaction between maximum temperature and sunshine hours, relative humidity, and precipitation, and the interaction between sunshine hours and MMD had a significant impact on O3 concentrations. The interaction between maximum temperature and sunshine hours played a leading role in changes of O3 concentration. The high temperature+strong radiation+MMD(about 2000 m) +no precipitation were conducive to the formation of O3 concentration, but in summer, only the maximum temperature, sunshine hours, and VC had the most significant effect on the O3 concentration, and strong high temperatures+strong radiation+the little horizontal wind in summer were conducive to the formation of O3 concentration near the surface. In summary, GAMs model can not only be used to identify the dominant influencing factors of O3 pollution, but also quantitatively analyze the influence of single effects and interaction of influencing factors on O3 concentration, which has great significance for the prevention and control of O3 pollution.