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

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.