Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 May 30;57(21):8026-8034.
doi: 10.1021/acs.est.3c00845. Epub 2023 May 16.

Unreported VOC Emissions from Road Transport Including from Electric Vehicles

Samuel J Cliff  1 , Alastair C Lewis  1   2 , Marvin D Shaw  1   2 , James D Lee  1   2 , Michael Flynn  3 , Stephen J Andrews  1   2 , James R Hopkins  1   2 , Ruth M Purvis  1   2 , Amber M Yeoman  1
Affiliations

Unreported VOC Emissions from Road Transport Including from Electric Vehicles

Samuel J Cliff et al. Environ Sci Technol. .

Abstract

There are widespread policy assumptions that the phase-out of gasoline and diesel internal combustion engines will over time lead to much reduced emissions of Volatile Organic Compounds (VOCs) from road transport and related fuels. However, the use of real-world emissions measurements from a new mobile air quality monitoring station demonstrated a large underestimation of alcohol-based species in road transport emissions inventories. Scaling of industry sales statistics enabled the discrepancy to be attributed to the use of ancillary solvent products such as screenwash and deicer which are not included in internationally applied vehicle emission methodologies. A fleet average nonfuel nonexhaust VOC emission factor of 58 ± 39 mg veh-1 km-1 was calculated for the missing source, which is greater than the total of all VOCs emitted from vehicle exhausts and their associated evaporative fuel losses. These emissions are independent of the vehicle energy/propulsion system and therefore applicable to all road vehicle types including those with battery-electric powertrains. In contrast to predictions, vehicle VOC emissions may actually increase given a predicted growth in total vehicle kilometers driven in a future electrified fleet and will undergo a complete VOC respeciation due to the source change.

Keywords: air pollution; ethanol; screenwash; urban atmosphere; volatile chemical products.

PubMed Disclaimer

Conflict of interest statement

The authors declare no competing financial interest.

Figures

Figure 1
Figure 1
Time series benzene, m/p-xylene, toluene, and trimethylbenzene at the Marylebone road, central London air quality monitoring station.
Figure 2
Figure 2
Median average diurnal profiles for six VOC species (benzene, ethanol, m-xylene, methanol, toluene, and trimethylbenzene) and both tracer species (CO2 and NOx) for the summer and winter at both measurement sites.
Figure 3
Figure 3
Median average diurnal profiles for traffic counts at the roadside site during the summer and winter measurement periods.
Figure 4
Figure 4
Box plots of measured VOC emission factors at the Manchester roadside using CO2 and NOx as tracer species, compared to COPERT calculated exhaust and evaporative emission factors as bars, faceted by season. In the top right of each facet is an expanded view of the aromatic emission factors to improve clarity.
Figure 5
Figure 5
(a) VOC emission projections for road transport for fuel-related and NFNE sources. Fuel-related emissions are proportionally reduced from 2020 estimates using projected electric vehicle fleet percentage. NFNE emissions are generated by multiplying the derived emission factor in this work (58 mg vh–1 km–1) by projected vehicle kilometers traveled in the U.K. (b) Electric vehicle proportion and UK annual vehicle kilometers traveled predictions used to produce (a) from DfT (Road Traffic Forecasts 2018). (c) A global timeline of commitments to the banning of new petrol and diesel vehicle sales. Data were mainly taken from COP 26 signatory list, but also from the EU “Fit for 55” proposal and the US Executive Order on Catalyzing Clean Energy Industries and Jobs through Federal Sustainability.
See this image and copyright information in PMC

References

    1. McDonald B. C.; de Gouw J. A.; Gilman J. B.; Jathar S. H.; Akherati A.; Cappa C. D.; Jimenez J. L.; Lee-Taylor J.; Hayes P. L.; McKeen S. A.; Cui Y. Y.; Kim S.-W.; Gentner D. R.; Isaacman-VanWertz G.; Goldstein A. H.; Harley R. A.; Frost G. J.; Roberts J. M.; Ryerson T. B.; Trainer M. Volatile chemical products emerging as largest petrochemical source of urban organic emissions. Science 2018, 359, 760–764. 10.1126/science.aaq0524. - DOI - PubMed
    1. Timmers V. R.; Achten P. A. Non-exhaust PM emissions from electric vehicles. Atmos. Environ. 2016, 134, 10–17. 10.1016/j.atmosenv.2016.03.017. - DOI
    1. Lewis A. C.; Hopkins J. R.; Carslaw D. C.; Hamilton J. F.; Nelson B. S.; Stewart G.; Dernie J.; Passant N.; Murrells T. An increasing role for solvent emissions and implications for future measurements of volatile organic compounds. Philos. Trans. R. Soc. A 2020, 378, 20190328.10.1098/rsta.2019.0328. - DOI - PMC - PubMed
    1. Winkler S. L.; Anderson J. E.; Garza L.; Ruona W. C.; Vogt R.; Wallington T. J. Vehicle criteria pollutant (PM, NOx, CO, HCs) emissions: how low should we go?. npj Clim. Atmos. Sci. 2018, 1, 1–5. 10.1038/s41612-018-0037-5. - DOI
    1. Li J.; Deng S.; Li G.; Lu Z.; Song H.; Gao J.; Sun Z.; Xu K. VOCs characteristics and their ozone and SOA formation potentials in autumn and winter at Weinan, China. Environ. Res. 2022, 203, 111821.10.1016/j.envres.2021.111821. - DOI - PubMed

Publication types

MeSH terms