The causes of ozone concentration growth in the night during the Shanghai Cooperation Organization Summit in Qingdao

To investigate the causes of ozone concentration increasing at night during the Shanghai Cooperation Organization Summit in Qingdao, the ground observation data and pollutant concentration data were used to analyze it in this study. As the results showed that, the ozone concentrations increased continuously with peak concentration of 194μg/m3, and the growth rate of 10.7μg/(m3•h) from 20:00 to 23:00 on the 6th. By using the NCEP/FNL reanalysis data, it could be known that ozone and its precursors emitted from Jiangsu and Anhui province were transmit to Qingdao under condition of southwest wind at night, and transmitted to the surface under the sinking movement in the boundary layer. By calculating the ventilation index of the boundary layer, height of the maximum wind speed decreased gradually in the boundary layer on the 6th, which met the standard of low-altitude jets, and the ventilation index increase fluctuation below 1000m at night, of which were 3900 and 5892m2/s at 500m and 500~1000m, respectively. What's more, the ozone pollution sources in Qingdao were simulated based on the Ozone Source Apportionment Technology (OSAT) in the CAMx air quality model. As the results indicated that the main sources areas were Jiangsu, Anhui province and Shanghai, with average contribution ratio of 62.3%, 16.6% and 8.6%, respectively. © 2020, Editorial Board of China Environmental Science. All right reserved.