A Study Of The Effects Of The Deterioration Of Light-duty Gasoline Passenger Cars On VOCs Emission And Ozone Forming Potentials

In recent years,ozone pollution has become a serious problem in Chinese cities,which has aroused widespread public concern.VOCs are important precursors of photochemical reaction,which are discharged into the air through the source of pollution and produce ozone by photochemical reaction.Light-duty passenger gasoline vehicles(g-LPV)are mainly emission sources of VOCs.The emission factors are greatly attributed to deterioration,the engine capacity and the accumulated mileages.Therefore,the research on the effect of the deterioration of g-LPV on VOCs emissions and ozone formation potentials has important significance for the establishment of control measures for ozone pollution.In this study,the g-LPV were classified according to the control technology level,the engine capacity and the accumulated mileages.Based on the chassis dynamometer testing method,the concentrations of 51 varieties of VOCs from different types of g-LPV were measured and converted into emission factors based on fuel consumption.Firstly,the effect of control technology levels,cumulated mileages and engine capacity on VOCs emissions were analyzed.Secondly,the ozone formation potentials of different vehicles were estimated by using Maximum Incremental Reactivity(MIR)method.Finally,the deterioration models for the emission factors of TVOCs and typical VOCs were established and used to estimate the emission lists of g-LPV under National III and National IV standards in 2017 preliminarily.The results show that the emission factors of different varieties of VOCs from g-LPV with different control levels,engine capacity and accumulated mileages differ greatly.Alkanes,aromatics and chlorinated hydrocarbons were the most abundant VOC in exhaust gas,which contributed 35.82-51.37%,22.5-42.4%and 12.7-21.4%of the total emissions.Aromatics(50.5-75.5%)contributes the most to the ozone forming potential,followed by olefins(13.5-39.6%).The total contribution of typical VOCs(butene,pentene,toluene,xylene,tritoluene and diethylbenzene)to ozone formation potentials was above 80%.The emission factors of TVOCs and typical VOCs were exponentially increasing with the increase of the accumulated mileages.It was estimated that the TVOCs emissions of g-LPV under National III and National IV standards were 93 8,700 and 466,600 tons respectively in 2017.