Investigation of VOC emission characteristics of light-duty gasoline vehicles and combustion-side formation mechanisms of key VOC species
- 1Vehicle Emission Control and Simulation Key Laboratory of Ministry of Ecology and Environment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; Vehicle Emission Control Center, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; College of Mechanical and Electrical Engineering, Qingdao University, Qingdao, Shandong, 266071, China
- 2Vehicle Emission Control and Simulation Key Laboratory of Ministry of Ecology and Environment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; Vehicle Emission Control Center, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
Abstract
Volatile organic compounds (VOCs) are important precursors of atmospheric ozone (O 3 ) and secondary organic aerosol (SOA), making their emissions an important concern for urban air quality. In this study, two light-duty gasoline vehicles (LDGVs), including one China V vehicle and one China VI vehicle, were tested over the Worldwide harmonized Light vehicles Test Cycle (WLTC) under normal TWC and simulated first-stage TWC failure conditions. VOC emissions were analyzed by driving phase, chemical group, and individual species, and their ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAFP) were evaluated. Chemical kinetic simulations were further conducted to investigate the combustion-side formation and transformation behavior of representative aromatic VOCs under controlled conditions. Simulated first-stage TWC failure markedly increased VOC emissions from both tested vehicles, with the total VOC emission factors of the tested China VI and China V vehicles increasing from approximately 22 and 31 mg/km to 78 and 103 mg/km, respectively. For the two tested vehicles, the low-speed phase exhibited the highest phase-specific VOC emission factor under normal TWC conditions, whereas the phase-specific VOC emission factor of the extra-high-speed phase increased markedly following simulated first-stage TWC failure. The VOC profile shifted toward higher contributions of alkanes, alkenes/alkynes, and aromatics. OFP was dominated by oxygenated VOCs (OVOCs) under normal TWC conditions but by aromatics and alkenes/alkynes under the simulated first-stage TWC failure condition, whereas SOAFP was primarily controlled by aromatic species. Under the controlled simulation conditions, xylene isomers mainly accumulated at 800-850 K through side-chain oxidation and HCO-elimination pathways, while toluene peaked at around 900 K and was related to the secondary conversion of xylene-derived intermediates. Increasing equivalence ratio enhanced H-assisted aromatic conversion and weakened oxidative consumption, thereby promoting the accumulation of toluene and xylene isomers.
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BibTeX
@article{zhao2026investigation,
title = {{Investigation of VOC emission characteristics of light-duty gasoline vehicles and combustion-side formation mechanisms of key VOC species}},
author = {Huayang Zhao and Jia Ke and Han Jiang and Miao Tian and Yunjing Wang and Yan Ding},
journal = {Atmospheric Environment: X},
year = {2026},
month = oct,
doi = {10.1016/j.aeaoa.2026.100525},
url = {https://doi.org/10.1016/j.aeaoa.2026.100525},
note = {CC BY},
}
RIS
TY - JOUR
TI - Investigation of VOC emission characteristics of light-duty gasoline vehicles and combustion-side formation mechanisms of key VOC species
AU - Huayang Zhao
AU - Jia Ke
AU - Han Jiang
AU - Miao Tian
AU - Yunjing Wang
AU - Yan Ding
PY - 2026
DA - 2026/10/30
JO - Atmospheric Environment: X
DO - 10.1016/j.aeaoa.2026.100525
UR - https://doi.org/10.1016/j.aeaoa.2026.100525
AB - Volatile organic compounds (VOCs) are important precursors of atmospheric ozone (O 3 ) and secondary organic aerosol (SOA), making their emissions an important concern for urban air quality. In this study, two light-duty gasoline vehicles (LDGVs), including one China V vehicle and one China VI vehicle, were tested over the Worldwide harmonized Light vehicles Test Cycle (WLTC) under normal TWC and simulated first-stage TWC failure conditions. VOC emissions were analyzed by driving phase, chemical group, and individual species, and their ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAFP) were evaluated. Chemical kinetic simulations were further conducted to investigate the combustion-side formation and transformation behavior of representative aromatic VOCs under controlled conditions. Simulated first-stage TWC failure markedly increased VOC emissions from both tested vehicles, with the total VOC emission factors of the tested China VI and China V vehicles increasing from approximately 22 and 31 mg/km to 78 and 103 mg/km, respectively. For the two tested vehicles, the low-speed phase exhibited the highest phase-specific VOC emission factor under normal TWC conditions, whereas the phase-specific VOC emission factor of the extra-high-speed phase increased markedly following simulated first-stage TWC failure. The VOC profile shifted toward higher contributions of alkanes, alkenes/alkynes, and aromatics. OFP was dominated by oxygenated VOCs (OVOCs) under normal TWC conditions but by aromatics and alkenes/alkynes under the simulated first-stage TWC failure condition, whereas SOAFP was primarily controlled by aromatic species. Under the controlled simulation conditions, xylene isomers mainly accumulated at 800-850 K through side-chain oxidation and HCO-elimination pathways, while toluene peaked at around 900 K and was related to the secondary conversion of xylene-derived intermediates. Increasing equivalence ratio enhanced H-assisted aromatic conversion and weakened oxidative consumption, thereby promoting the accumulation of toluene and xylene isomers.
SN - 2590-1621
ER -