Direct identification of total and missing OH reactivities from light-duty gasoline vehicle exhaust in China based on LP-LIF measurement  

作　　者：Xuehui Liu Zibing Yuan Qing’e Sha Shengrong Lou Hongli Wang Xin Li Junyu Zheng Bin Yuan Min Shao 

机构地区：[1]School of Environment and Energy,South China University of Technology,Guangzhou 510006,China [2]Institute of Environmental and Climate Research,Jinan University,Guangzhou 511443,China [3]State Environmental Protection Key Laboratory of the Cause and Prevention of Urban Air Pollution Complex,Shanghai Academy of Environmental Sciences,Shanghai 200233,China [4]College of Environmental Science and Engineering,Peking University,Beijing 100871,China

出　　处：《Journal of Environmental Sciences》2023年第11期107-117,共11页环境科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.91644221 and 41627809);the National Key Research and Development Program of China(Nos.2016YFC0202201 and 2018YFC0213904);the Key-Area Research and Development Program of Guangdong Province(No.2019B110206001).

摘　　要：Considerable efforts have been devoted to characterising the chemical components of vehicle exhaust.However,these components may not accurately reflect the contribution of vehicle exhaust to atmospheric reactivity because of the presence of species not accounted for(“missing species”)given the limitations of analytical instruments.In this study,we improved the laser photolysis–laser-induced fluorescence(LP-LIF)technique and applied it to directly measure the total OH reactivity(TOR)in exhaust gas from light-duty gasoline vehicles in China.The TOR for China Ⅰ to Ⅵ-a vehicles was 15.6,16.3,8.4,2.6,1.5,and 1.6×10^(4) sec^(-1),respectively,reflecting a notable drop as emission standards were upgraded.The TOR was comparable between cold and warm starts.The missing OH reactivity(MOR)values for China Ⅰ to Ⅳ vehicles were close to zero with a cold start but were much higher with a warm start.The variations in oxygenated volatile organic compounds(OVOCs)under different emission standards and for the two start conditions were similar to those of the MOR,indicating that OVOCs and the missing species may have similar production processes.Online measurement revealed that the duration of the stable driving stage was the primary factor leading to the production of OVOCs and missing species.Our findings underscore the importance of direct measurement of TOR from vehicle exhaust and highlight the necessity of adding OVOCs and other organic reactive gases in future upgrades of emission standards,such that the vehicular contribution to atmospheric reactivity can be more effectively controlled.

关 键 词：Total OH reactivity LP-LIF Missing OH reactivity Emission standard Light-duty gasoline vehicle 

分 类 号：X831[环境科学与工程—环境工程]