机动车来源多环芳烃及其衍生物的排放特征研究进展

Research progress of emission characteristics of polycyclic aromatic hydrocarbons and their derivatives of vehicle exhaust

随着机动车保有量快速增长,机动车排放成为大部分大中城市大气中PAHs及其衍生物的主要来源之一.因此,基于以往的研究成果,汇总了台架实验、车载实验、隧道实验、路边实验等常用的机动车尾气采集方法,对机动车来源PAHs及其衍生物的排放特征(排放因子、气粒分配规律、成分谱研究以及机动车车型、工况和行驶里程的影响等)进行了总结,为不同研究需求下实验方法的选取以及机动车减排措施的制定提供科学参考.此外,为缓解能源问题和机动车排放污染问题,中国计划2020年在全国范围内推广使用车用乙醇汽油.由于乙醇汽油与普通汽油的性质存在诸多不同,乙醇汽油对机动车排放的影响也引起了研究者们的关注,因此分析了乙醇汽油实施对机动车尾气PAHs及其衍生物的污染特征变化的影响,以期为该领域未来的研究方向提供建议,为机动车污染防控研究提供科学合理的参考.

Polycyclic aromatic hydrocarbons(PAHs)are a type of persistent organic pollutants with carcinogenic,teratogenic,and mutagenic effects.Moreover,the derivatives of PAHs,including nitro-PAHs(NPAHs)and oxygenated-PAHs(OPAHs),have strong oxidizing properties,and their mutagenicity and carcinogenic potential can reach 10 times and 100,000 times of the parent PAHs,respectively.Various epidemiological and toxicological studies have shown that PAHs and their derivatives are closely related to the occurrence and growth of many critical diseases.Therefore,PAHs have received immense attention in academics and is becoming a hot topic in scientific research.In recent years,a rapid increase in the number of motor vehicles has resulted in emissions from vehicles that have become one of the primary sources of PAHs and their atmospheric derivatives in almost all large and medium-sized cities.Based on the previous research,this review has summarized several standard sampling methods for vehicle exhaust,including bench experiment,vehicle-mounted experiment,tunnel experiment,and roadside experiment,and concluded the characteristics of PAHs and their derivatives from vehicle emissions(i.e.,emission factor,gas-particle phase partitioning,source profiles,the influence of vehicle type,operating condition,and vehicle mileage).This review also provides scientific references for collecting sampling methods under various research demands by formulating emission reduction measures for motor vehicles.The oxygen content of ethanol–gasoline is higher than that of regular gasoline.The use of ethanol–gasoline can reduce many kinds of harmful substances in vehicle exhaust.At the same time,as straw is one of the raw materials of bioethanol,the promotion of ethanol gasoline for vehicles is also an important measure to solve the problem of burning agricultural waste such as straw and reduce the emission of pollutants.In this context,China plans to promote using vehicles with the ethanol–gasoline fuel nationwide in 2020 to alleviate the problem of pollution due to energy and motor vehicle emissions.However,there are certain differences in the properties between ethanol–gasoline and regular gasoline;hence,the impact of ethanol-blended gasoline on emissions from motor vehicles has attracted the attention of researchers.This paper reviewed the effect of ethanol-blended gasoline on the variation of pollution characteristics of PAHs and discussed their derivatives.Some useful suggestions for future research directions in this field are made,and scientific and reasonable references for the prevention and control measures of motor vehicle emission reduction are provided.