CORRELATION ANALYSIS OF PM2.5 AND O-3 IN DRY AND RAINY SEASONS IN HONG KONG AND GUANGZHOU FROM 2016 TO 2021

Based on the environmental monitoring and meteorological data of Hong Kong and Guangzhou from 2016 to 2021, the correlation between PM2.5 and O-3 under rainy and dry seasons is analyzed, and so does the role of meteorological factors in the interaction between PM2.5 and O-3. Through analysis, it is found that in rainy seasons, PM2.5 and O-3 in Hong Kong and Guangzhou are positively correlated, and the correlation coefficients are 0.77 and 0.46, respectively. However, in dry seasons, there is a weak correlation between PM2.5 and O3 in Hong Kong, with a correlation coefficient of 0.17, and a negative correlation between PM2.5 and O-3 in Guangzhou, with a correlation coefficient of -0.13. This indicates that the precipitation may contribute to different interaction between PM2.5 and O-3. On the other hand, in the rainy seasons, the contribution concentration of primary PM2.5 is basically unchanged and the contribution rate decreases gradually, while the contribution concentration and contribution rate of secondary PM2.5 increases with the increase of photochemical level. After taking the solar radiation, temperature and atmospheric oxidation of Hong Kong and Guangzhou in rainy and dry seasons into account, the impact of O-3 on PM2.5 is dominant in rainy seasons and the inhibition of PM2.5 on O-3 is dominant in dry seasons.