Pollution Characteristics of PM2.5 and O3 under Atmospheric Circulation Types in the Yangtze River Delta Region during 2014-2019
Based on the PM2.5 and O3 monitoring data and NCEP-FNL data(i.e geopotential height and u、v wind at 925 hPa)in the fall and winter(i.e.,January,February,November,and December)and the warm season(i.e.,April-October)in the central-eastern region of China from 2014 to 2019,typical atmospheric circulation types(CTs)were recognized via T-mode PCA classification method.The results showed that during the research period,seventeen CTs affected air quality in the Yangtze River Delta region(YRD region),and the CTs that were prone to the occurrence of PM2.5 and O3 pollution were furtherly identified.High PM2.5 concentration in autumn and winter(i.e.,January,February,November,and December)were usually related to cold front(AW_CT2)and High Pressure Moving to Sea(AW_CT3 and AW_CT5)weather system.Atmospheric circulation conditions may be conductive for upstream pollutant transport for AW_CT2 and local accumulation for AW_CT3 and AW_CT5 respectively.While high ozone concentration in warm season(i.e.,from April to October)were associated to subtropical high control(Spring_CT1 and Summer_CT1)and uniform pressure field(Summer_CT3 and Autumn_CT2),but there may be differences in the impacts of meteorological characteristics and photochemical processes for O3 pollution.The O3 polluted days and MDA8 O3 concentrations in the five cities of the YRD region were higher than those controlled by other CTs in the same seasons.Moreover,double high pollution was frequently occurred in Shanghai,Hangzhou and Nanjing under subtropical high control and uniform pressure field.
Atmospheric circulation typePM2.5OzoneDouble high pollutionYangtze River Delta
NETL
NSTL
万方数据
