Ambient ozone(O3)was first identified as a key harmful air pollutant in the study of photochemical smog during the 1950s in Los Angeles.Subsequent studies uncovered that surface O3 was not emitted directly,but formed ...Ambient ozone(O3)was first identified as a key harmful air pollutant in the study of photochemical smog during the 1950s in Los Angeles.Subsequent studies uncovered that surface O3 was not emitted directly,but formed from the reactions of nitrogen oxides(NO_(x))and volatile organic compounds(VOCs)in sunlight.Quantifying the relationship between O3 and its two main precursors,NOx and VOCs,is considered to be the cornerstone for enabling successful mitigation of O3.In the past,a central area for the study and practice of O3 pollution control was Los Angeles and the surrounding area.The ambient O3 concentrations in the area were successfully and continuously reduced from 400 ppb(1 ppb=109 m^(3)/m^(3))to ca.120 ppb due to the joint mitigation of VOC and NOx emissions from 1960 to 2010[1].Nevertheless,O3 pollution still represents one of the most pervasive and stubborn environmental problems in megacities worldwide,with many populous centres regularly breaching WHO 8-hour Interim Targets-1 levels(160 lg/m^(3)),not to mention the updated air quality guideline value of 100 lg/m^(3).The difficulty of O3 pollution control is due to a number of factors,including its non-linear relationship with NOx[2],the difficulty of anthropogenic VOC control[3]and the contributions of biogenic VOCs.展开更多
基金supported by the Natural Science Foundation of Beijing Municipality(JQ19031)the National Natural Science Foundation of China(22221004,91844301,and 91544225).
文摘Ambient ozone(O3)was first identified as a key harmful air pollutant in the study of photochemical smog during the 1950s in Los Angeles.Subsequent studies uncovered that surface O3 was not emitted directly,but formed from the reactions of nitrogen oxides(NO_(x))and volatile organic compounds(VOCs)in sunlight.Quantifying the relationship between O3 and its two main precursors,NOx and VOCs,is considered to be the cornerstone for enabling successful mitigation of O3.In the past,a central area for the study and practice of O3 pollution control was Los Angeles and the surrounding area.The ambient O3 concentrations in the area were successfully and continuously reduced from 400 ppb(1 ppb=109 m^(3)/m^(3))to ca.120 ppb due to the joint mitigation of VOC and NOx emissions from 1960 to 2010[1].Nevertheless,O3 pollution still represents one of the most pervasive and stubborn environmental problems in megacities worldwide,with many populous centres regularly breaching WHO 8-hour Interim Targets-1 levels(160 lg/m^(3)),not to mention the updated air quality guideline value of 100 lg/m^(3).The difficulty of O3 pollution control is due to a number of factors,including its non-linear relationship with NOx[2],the difficulty of anthropogenic VOC control[3]and the contributions of biogenic VOCs.
