Abstract: Based on the daily average air quality monitoring data of national control stations in Zigong area from 2014 to 2018, the temporal and spatial variations of PM2.5 concentration in Zigong city were analyzed by using multi-scale data. The results showed that the hourly variation trend of PM2.5 concentration in Zigong area was mainly related to human activities and solar irradiation time; The ratio of days of PM2.5 concentration per day reaching the first-class national air quality standard was 27.5%, and the ratio of days reaching the second-class standard was 73.5%; The period of high PM2.5 concentration was mainly in January, February and December; And it had the distribution characteristics of high in spring, autumn, winter and low in summer, and the proportion of days exceeding the standard in winter was as high as 69.02%. The spatial distribution characteristics of PM2.5 concentration were not only affected by the location of monitoring sites, topography, climate and urban structure, but also closely related to the contribution of wind direction and other pollution sources in surrounding cities. Overall, PM2.5 concentration levels were higher in Da'an, Gaoxin and Gongjing district with high industrial output, frequent transportation and dense population.

Key words: monitoring data, PM2.5 concentration, spatial-temporal feature, Zigong city