Analysis on the Characteristics and Causes of Ozone Pollution in Nanjing in the Spring of 2022
Affected by the new round of COVID-19 in the spring of 2022,cities in the Yangtze River Delta adopted a series of control measures,resulting in a reduction in the emission level of air pollutants.The variation characteristics of six pollutants,especially ozone(O3),in Nanjing and Yangtze River Delta in the spring(from March to May)of 2022 were analyzed.From the aspects of meteorological factors and O3 precursors,and using observation-based models(OBM),the cause of variation of O3 pollution in Nanjing were studied.Key active components and sources of volatile organic compounds(VOCs)of Nanjing were analyzed.The results showed that:compared with that in 2021,the average concentrations of PM2.5,PM10,NO2 and CO all decreased,but O3-8 h concentration increased by 19.8%and days of O3-8 h exceeding standard increased by 9 days in Nanjing,and O3-8 h concentration increased by 17.9%,and the number of days of O3-8 h exceeding standard increased by 1.5 times in the Yangtze River Delta in the spring of 2022.On the one hand,the rise of O3 concentration in Nanjing was due to unfavorable meteorological conditions,on the other hand,O3 generation in Nanjing was more sensitive to VOCs,but reduction percentage of nitrogen oxides(NOx)concentration was more than that of VOCs,and combined with the analysis results of O3 precursor emission reduction scheme,it was found that the improper emission reduction ratio of VOCs and NOx could lead to O3 concentration rising instead of falling.The key active species of VOC for ozone generation of Nanjing were acetaldehyde,propylene,m/p-xylene,acrolein and ethylene.The results of positive matrix factorization(PMF)showed that vehicle exhaust was the main source of VOCs in Nanjing urban area,followed by LPG/NG use and petrochemistry.
NETL
NSTL
万方数据
