Abstract
This study based on daily data of six major pollutants (PM2.5, PM10, SO2, NO2, CO and O3) from 2016 to 2020, the spatiotemporal variation characteristics of air quality in Panzhihua and its surrounding cities were analyzed. On this basis, trajectory model is used to analyze the origin and direction of migration of the pollutants in the days with high pollution degree, so as to find a method to prevent and control the air pollution in the cities with special geographical location. The results show that the concentration of pollutants in the study area showed an overall downward trend, but Ozone showed an opposite trend. The air quality in the study area has been significantly improved. Air quality was the best in 2018, followed by 2020. The annual variation trend of PM2.5, PM10, SO2, NO2 and CO is U-shaped (flat W), while the O3 is M-shaped. In addition, the monthly average concentration of pollutants in Panzhihua is higher than these in its surrounding cities. O3 has a significant correlation with its various precursor pollutants, and the air pollution situation is complex and diverse. According to the analysis of pollutant diffusion trajectory, the direction of pollution source in Panzhihua city is southwest and the diffusion direction is east and southeast.