Academia has carried out extensive research on the pressing issue of regional air quality and achieved rich results in which its perspective has mainly focused on two aspects. The first is related to the spatio-temporal variation of regional air quality. The characterization indexes of air quality usually have included a single pollutant, such as SO
2, NO
2, O
3, PM
10, and PM
2.5 (Liu and Du,
2016; Xu and Li,
2016; Li
et al.,
2020) and a comprehensive air quality index, such as air pollution index (API) (Deng
et al.,
2013) and air quality index (AQI ) (Lin and Wang,
2016; Zhang
et al.,
2020) among others. The time scales involved in the research include daily, monthly, seasonal, and inter-annual evolutionary characteristics (Chen
et al.,
2015; Dai
et al.,
2020). The regional scale and spatial scope are also diverse, and include countries and provinces (Guo
et al.,
2019; Wang
et al.,
2019), urban agglomerations (such as the Beijing-Tianjin-Hebei urban agglomeration and the surrounding areas (Cheng
et al.,
2019), and the Yangtze River Delta (Chen
et al.,
2017)). Such features as the spatial agglomeration and spatial spillover can affect air pollution (Li
et al.,
2019). The second aspect is concerned with the impact factors of air quality. Air pollution is formed under the dual effects of natural meteorological factors and socio-economic activities, so its overall mechanism is more complex. Research shows that climatic-meteorological factors such as dust (Liao
et al.,
2016), wind (Yu
et al.,
2018), precipitation (Yang
et al.,
2019), and temperature (Wang and Wang,
2018), together with physio-geographical factors such as topography (Long
et al.,
2016) and vegetation (Liu
et al.,
2017b), exert a direct impact on the detention time and concentration of pollutants to either strengthen or slow down the interaction between pollutants. Such interactions ultimately affect the regional air quality through regional transmission, diffusion of air pollutants, and self-purification of air. Meanwhile, socio-economic activities are the main source of air pollutants. Some scholars have discussed the influence of socio-economic factors such as economic growth, industrial structure (Liu
et al.,
2017c), urbanization (Jiang
et al.,
2019), industrialization (Wang
et al.,
2019b), land use (Xu
et al.,
2015), foreign direct investment (FDI) (Jiang
et al.,
2018), and population density (Liu
et al.,
2017a) on air quality. Their research methods include a spatial econometric model (Bai
et al.,
2018; Liu
et al.,
2018), a geographically weighted regression (GWR) model (Bai
et al.,
2019), a geographic detector model (Zhang and Gong,
2018), principal component analysis, and a multiple linear regression model (Cheng
et al.,
2019). Generally speaking, the existing research on regional air quality mainly focuses on a single pollutant or the spatio-temporal characteristics of multiple pollutants over a single year. Yet, research that focuses on comprehensive evaluations based on multiple pollutants over multiple years is limited. Research on impact factors has paid less attention to the interaction between different types of air pollutants. In addition, most models are affected by the collinearity between variables, thus restricting their interpretation and robustness, causing them to be potentially ineffective in identifying the dominant impact factors. Urbanization, a geographical process dominated by human activities, is subjected to mutual feedback with the environmental system (Chen,
2015). The urban atmospheric-environmental system results from interactions between humans and nature; therefore, research on the impact factors and driving mechanisms of urban air quality still needs to be deepened.