Analysis of urban air quality and pollutant changes in Shandong Province from 2015 to 2019

: In this paper, the heavily polluted cities of Jinan, Zibo, Dongying and Linyi in Shandong Province were taken as the study area. Based on the daily air quality and pollutant concentration data from 2015 to 2019, the change of air quality and pollutant concentration in the study area was analyzed from four time scales of year, month, working day and day by time series analysis, combined with meteorological, industrial and other influencing factors. The analysis showed that: (1) With the implementation of the blue Sky Defense plan in 2018, the air quality in the study area was significantly improved, and the decrease of SO2, PM2.5 and CO was the largest, the percentage reduction was 41.5%, 62.36%, 39.35%; (2): Monthly variation: it shows a "W" -shaped variation, with severe pollution in winter and light pollution in early autumn; (3) Working days and rest days show an "S" -shaped change, with Tuesday as the pollution trough and Saturday as the pollution peak; (4) A "convex" type of fluctuation was observed, with the heaviest pollution in the middle of the month and lighter pollution in the beginning and end of the month.