Electric vehicles are often seen as a ‘silver bullet’ to the problem of air pollution. While it is true that a move to electric and other alternatively fuelled vehicles will cause large and welcome improvements in roadside nitrogen dioxide, the evidence for reductions in particulate matter (PM) concentrations is less compelling.
A key part of the problem relates to non-exhaust emissions. Technological improvements have delivered impressive reductions in PM emissions from vehicle’s exhaust pipes and, as a result, most traffic-related PM now comes from sources such as tyre wear, brake wear, and road wear. Reducing emissions from these sources is more challenging than for the exhaust stream, in part simply because the emissions sources are not contained. No legislation is currently in place specifically to target non-exhaust emissions.
AQC’s Ben Marner was privileged to join some of the leading academic researchers in the world to summarise the evidence on this issue. The review built on work published in 2019 by the same team, then working as Defra’s Air Quality Expert Group (AQEG). The new review summarises the current state of evidence on non-exhaust PM and volatile organic compounds (VOCs) from road traffic, including emissions sources, modelling approaches, likely future trends, and abatement options. It highlights the scale of the remaining challenge for roadside air pollution, but provides a robust and thorough evidence base for developing future policies and actions.
Harrison, R.M., Allan J., Carruthers, D., Heal, M.R., Lewis, A.C., Marner, B., Murrells, T., and Williams, A. Non-exhaust vehicle emissions of particulate matter and VOC from road traffic: A review. Atmospheric Environment 262, 2021.
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