基于OMI数据的新冠疫情影响下福建省臭氧敏感性变化

The change of atmospheric ozone formation sensitivity in Fujian Province based on OMI satellite data during the period of COVID-19

基于OMI卫星数据,利用臭氧敏感性指示剂法研究了福建省及其九地市在COVID-19疫情影响下不同时间阶段大气臭氧敏感性特征以及不同情景下敏感性的变化规律.结果表明,在疫情前,福建省的大气臭氧生成控制区面积占比情况为VOCS控制区占46.5%、协同控制区占25.0%、NO_(x)控制区占28.5%,以VOCs控制区为主,其中厦门市占比最高,南平市最低;在严控期,VOCS控制区占29.5%、协同控制区占21.1%、NO_(x)控制区面积占49.4%,以NO_(x)控制区为主,其中宁德市占比最高,莆田市最低;在平稳期,VOCS控制区占23.1%、协同控制区占29.1%、NO_(x)控制区占47.8%,以NO_(x)控制区为主,其中南平市占比最高,厦门市最低.与疫情前相比,严控期厦门市VOCS控制区面积占比减少最多(38.1%)、最少的是三明市(7.9%);从转化结果来看,第一类城市包括莆田市、泉州市、厦门市,敏感区变化受前体物HCHO、NO2共同影响,而第二类城市主要受NO2柱浓度变化影响.因此,第一类城市臭氧调控更加复杂.

Based on the OMI satellite data,the characteristics of atmospheric ozone sensitivity in Fujian province and its nice municipalities during the period of COVID-19 epidemic were assessed with HCHO and NO2 vertical column densities as proxies for ozone sensitivity.The results showed that Fujian Province was dominated by VOCs-limited regime before the pandemic with the controlled area proportion of 46.5%.The other two regimes:NO_(x)-VOCs-limited regime and NO_(x)-limited regime,controlled 25.0%and 28.5%of the area,respectively.The area proportion controlled by VOXs-limited regime was highest in Xiamen and lowest in Nanping.During the period with strict pandemic control policies,VOXs-limited regime,NO_(x)-VOCs-limited regime and NO_(x)-limited regime controlled 29.5%,21.1%,and 49.4%of the area,respectively.The area proportion controlled by NO_(x)-limited regime was highest in Ningde and lowest in Putian.During the stable period,VOXs-limited regime,NO_(x)-VOCs-limited regime and NO_(x)-limited regime controlled 23.1%,29.1%,and 47.8%of the area,respectively.NO_(x)-limited regime was the dominant regime with highest area proportion controlled in Nanping and lowest area proportion in Xiamen.Compared with the before pandemic period,the area proportion of Xiamen controlled by VOCs-limited regime was obviously reduced(38.1%less)during the period with strict control policies,and the lowest reduction was in Sanming with a moderate decrease of 7.9%.According to the conversion results,Putian,Quanzhou,and Xiamen were categorized into the first city group where changes in ozone sensitivity were jointly influenced by its precursors including formaldehyde(HCHO)and nitrogen dioxide(NO2),while other cities could be categorized into the second group where ozone sensitivities were mainly affected by NO2 column concentrations.Therefore,effective strategies for ozone reduction would be more complex in the first group of cities.