Intermediate and semi-volatility organic compounds(I/SVOCs)are crucial precursors for secondary organic aerosols(SOA).Vehicles are major sources of I/SVOCs,yet their emission profiles remain insufficiently characteriz...Intermediate and semi-volatility organic compounds(I/SVOCs)are crucial precursors for secondary organic aerosols(SOA).Vehicles are major sources of I/SVOCs,yet their emission profiles remain insufficiently characterized.We conducted dynamometer tests on eight in-use gasoline and diesel vehicles(DVs),employing non-targeted analysis with comprehensive two-dimensional gas chromatography coupled with high-resolution mass spectrometry(GC×GC-TOFMS)to investigate vehicular I/SVOC emissions at the molecular level.A total of 438 and 424 compounds were identified and(semi)-quantified in the gas and particle phases,respectively.DVs exhibited higher emission factors(376.7±74.9 mg/(kg·fuel))compared to gasoline vehicles(GVs)(114.4±42.1 mg/(kg·fuel))across both phases.Alkanes(29.7%-41.9%),single-ring aromatics(2.6%-29.8%),and cycloalkanes(1.0%-13.1%)were dominant I/SVOCs groups.Oxygenated I/SVOCs were more abundant in particulate phases(40.3%-56.8%)than in gas phases(14.4%-15.3%).Upgrading emission standards reduced organic emissions by 89.2%from China IV to China VI for DVs,particularly in the particle phase.Coldstart conditions resulted in higher I/SVOC emissions(528.4 mg/(kg·fuel))than hot-starts(224.8 mg/(kg·fuel))due to reduced combustion efficiency and suboptimal after-treatment performance at low temperatures.Our composition-based SOA estimation method improved SOA predictions by 1.5 and 1.2 times for diesel and GVs,respectively,compared to the traditional bin approach.These findings provide valuable insights into the molecular composition of vehicular I/SVOCs and their environmental impacts.展开更多
Previous studies have demonstrated that intermediate-volatility and semivolatile organic compounds(I/SVOCs) are important precursors of secondary organic aerosols. Motor vehicles are important sources of atmospheric I...Previous studies have demonstrated that intermediate-volatility and semivolatile organic compounds(I/SVOCs) are important precursors of secondary organic aerosols. Motor vehicles are important sources of atmospheric I/SVOC emissions. In this paper, existing test methods for motor vehicle I/SVOCs are summarized, the advantages and disadvantages of various sampling methods and analytical techniques are compared, and the main factors influencing motor vehicle I/SVOC emissions are analyzed. The results show that the onboard test method compensates for the shortcomings of the bench test method, reflects the emission characteristics of I/SVOCs on actual roads, and has great application potential. The identification capability of traditional gas chromatography-mass spectrometry for I/SVOCs is very limited, whereas the high sensitivity and species identification capability of comprehensive two-dimensional gas chromatography provide obvious advantages in the study of I/SVOC samples. Motor vehicle I/SVOC emissions are influenced by many factors. The individual and combined effects of different factors remain uncertain, so the importance of control variables must be more notably emphasized in future studies of influencing factors. In this paper, a systematic review is offered that could serve as a valuable reference for future research on motor vehicle I/SVOC emissions and contribute to mitigating fine particulate matter pollution.展开更多
基金supported by the National Key Research and Development Program of China(Nos.2023YFC3706201 and 2022YFE0135000)the National Natural Science Foundation of China(Nos.42175123 and 42311530112)the Fundamental Research Funds for the Central Universities of China(Nos.63241318,63241322,and 63243126).
文摘Intermediate and semi-volatility organic compounds(I/SVOCs)are crucial precursors for secondary organic aerosols(SOA).Vehicles are major sources of I/SVOCs,yet their emission profiles remain insufficiently characterized.We conducted dynamometer tests on eight in-use gasoline and diesel vehicles(DVs),employing non-targeted analysis with comprehensive two-dimensional gas chromatography coupled with high-resolution mass spectrometry(GC×GC-TOFMS)to investigate vehicular I/SVOC emissions at the molecular level.A total of 438 and 424 compounds were identified and(semi)-quantified in the gas and particle phases,respectively.DVs exhibited higher emission factors(376.7±74.9 mg/(kg·fuel))compared to gasoline vehicles(GVs)(114.4±42.1 mg/(kg·fuel))across both phases.Alkanes(29.7%-41.9%),single-ring aromatics(2.6%-29.8%),and cycloalkanes(1.0%-13.1%)were dominant I/SVOCs groups.Oxygenated I/SVOCs were more abundant in particulate phases(40.3%-56.8%)than in gas phases(14.4%-15.3%).Upgrading emission standards reduced organic emissions by 89.2%from China IV to China VI for DVs,particularly in the particle phase.Coldstart conditions resulted in higher I/SVOC emissions(528.4 mg/(kg·fuel))than hot-starts(224.8 mg/(kg·fuel))due to reduced combustion efficiency and suboptimal after-treatment performance at low temperatures.Our composition-based SOA estimation method improved SOA predictions by 1.5 and 1.2 times for diesel and GVs,respectively,compared to the traditional bin approach.These findings provide valuable insights into the molecular composition of vehicular I/SVOCs and their environmental impacts.
基金supported by the Natural Science Foundation of Beijing Municipality (No.8222041)the National Key Research and Development Program of China (No.2022YFC3700604)。
文摘Previous studies have demonstrated that intermediate-volatility and semivolatile organic compounds(I/SVOCs) are important precursors of secondary organic aerosols. Motor vehicles are important sources of atmospheric I/SVOC emissions. In this paper, existing test methods for motor vehicle I/SVOCs are summarized, the advantages and disadvantages of various sampling methods and analytical techniques are compared, and the main factors influencing motor vehicle I/SVOC emissions are analyzed. The results show that the onboard test method compensates for the shortcomings of the bench test method, reflects the emission characteristics of I/SVOCs on actual roads, and has great application potential. The identification capability of traditional gas chromatography-mass spectrometry for I/SVOCs is very limited, whereas the high sensitivity and species identification capability of comprehensive two-dimensional gas chromatography provide obvious advantages in the study of I/SVOC samples. Motor vehicle I/SVOC emissions are influenced by many factors. The individual and combined effects of different factors remain uncertain, so the importance of control variables must be more notably emphasized in future studies of influencing factors. In this paper, a systematic review is offered that could serve as a valuable reference for future research on motor vehicle I/SVOC emissions and contribute to mitigating fine particulate matter pollution.
