Variation Trend and Pollution Characteristics of Ambient Air Quality in Sichuan Province from 2015 to 2022
Based on the environmental monitoring data of air pollutant in Sichuan from 2015 to 2022,the variation trend and pollution characteristics of air quality were analyzed.The results indicated that from 2015 to 2022,the air quality of Sichuan had improved significantly,except for O3,which showed an increasing trend,the other 5 pollutants showed a decreasing trend or no significant change.Compared with that of 2015,the 90 th percentile of O3-8 h increased by 20%in 2022,while PM2.5,PM10,SO2,CO and NO2 decreased by 26.2%,28.4%,50%,28.6%and 14.8%respectively.In addition to the 2015-2017 PM2.5 failed to meet national air standards,the other years all pollutants met it.The average percentage of days meeting air quality standard was 83.8%-90.7%,showing a fluctuating increasing trend,and the number of days under heavy pollution and above decreased year by year.The concentration of PM2.5,PM10 showed a clear seasonal variation with high values in winter and spring and low values in autumn and summer,and NO2,CO with high values in winter and low values in summer,and O3 with high values in summer and spring and low values in autumn and winter,while the concentration of SO2 showed no obvious seasonal variation.The ambient air pollution situation had changed from the leading stage of PM2.5 in 2015-2017 to the combined pollution stage of PM2.5 and O3 in 2018-2022.The amount of nonattainment days of PM2.5 mainly occurred in winter(from December to January),and the O3 mainly occurred in summer(from June to August),and the amount of nonattainment days of O3 in spring(from March to May)could not be ignored.The average percentage of low-level O3 light pollution(161-175 μg/m3)and low-level PM2.5 light pollution(76-85 μg/m3)in nonattainment days was 49.8%and 39.9%respectively.Eliminating low-level O3 light pollution could greatly improve the average percentage of attainment days,but the marginal effect of reducing PM2.5 concentration to eliminate low-level light pollution was low.From 2015 to 2022,the monthly distribution range of PM2.5 nonattainment days narrowed year by year and concentrated in winter,while the O3 generally expanded and expanded to spring.The spatial distribution of PM2.5 and O3 showed the pollution characteristics of"high values in the east and low values in the west".The range of spatial distribution narrowed greatly of PM2.5 high concentration values and tended to be uniform,and the range of O3 expanded year by year.According to the analysis of typical pollution processes,O3 pollution in the Sichuan Basin in summer was usually affected by precursor VOCs emission and occurred under dry and high temperature conditions,while PM2.5 pollution in winter was usually affected by adverse meteorological condition such as calm wind and inversion layer,and was aggravated by secondary transformation of precursor.Influenced by the total emission reduction of pollutants,adjust and optimize the industrial structure and energy consumption structure,and other factors,the air quality had a significant improvement.
NETL
NSTL
万方数据
