Correlation Analysis on Pollution Characteristics and Spatiotemporal Changes of PM2.5 and O3——Taking Nanchong City as an Example
Rapid economic development over the past decades has caused serious air pollution problems in China,with high concentrations of fine particulate matter(PM2.5)and ozone(O3),while PM2.5 and O3 have become the two major air pollutants in China in recent years,especially in densely populated cities.Fluctuations in PM2.5 and O3 are strongly dependent on weather processes and anthropogenic emissions.The co-pollution of PM2.5 and O3 not only harms human health,but also harms social economy,which has become a key issue in air pollution con-trol and co-management.In order to integrate the control methods of PM2.5 and O3,it is necessary to analyze the correlation between PM2.5 and O3 concentration and understand the impact of meteorology on the two pollutants.To explore the mechanism of PM2.5 and O3 pollution,the main urban area of Nanchong City(Shunqing District,Gaoping District and Jialing District)is selected as the research area.Based on the data of Sichuan Province air quality monitoring network management system,origin and Excel are used to analyze the pollution status,spatio-temporal trends and influencing factors of PM2.5 and O3 in the ambient air of Nanchong City.The correlation be-tween them is discussed by Pearson.The results showed that:①the interannual variation of PM2.5 and O3 pollution in the main urban area of Nanchong City showed a downward trend from 2018 to 2022.O3 pollution rebounded in 2022,and the O3 concentration reached the standard in the past five years.②from the perspective of seasonal vari-ation,PM2.5 showed a"valley pattern"of high in winter and spring and low in summer and autumn.O3 presents a completely opposite trend to PM2.5,that is,the"peak type"change trend is high in summer and autumn and low in winter and spring.By comparing the observation results of PM2.5 and O3,it is found that both PM2.5 and O3 show obvious seasonal changes.③O3 exceeding the standard usually occurs at 3 to 5 PM,while PM2.5 concentration in-creases at around 11 PM.④The trend of O3 and PM2.5 concentrations at various atmospheric monitoring stations in Nanchong City shows that the O3 and PM2.5 concentrations are affected by humidity,temperature and wind speed.
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