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Scientific rational for IONA

The Problem

• Air pollution has been shown to contribute to one in eight deaths globally 
• People with asthma are disproportionately impacted by air pollution
• In order to reduce air pollution governments are targeting policies which reduce fossil fuelled vehicles
• Very little work examines the impacts of non-exhaust emissions

Solving one problem creates another

• Heavier vehicles increase non-tail pipe emissions: Electric and hybrid vehicles produce less air pollution from exhausts but due to their increased weight, they increase air pollution from tyre and road wear
• Reductions in particulate matter PM10 and PM2.5 that might be expected from the switch to electric vehicles may not be realised (Figure)
• While the reduction of exhaust emissions will undoubtedly be beneficial for health of society, the health effects of an increase non-tailpipe emissions remains to be determined
• These non-exhaust particulate matter are capable of causing immune responses which could be linked to worsening of asthma symptoms and other health conditions

Julia C. Fussell, Meredith Franklin, David C. Green, Mats Gustafsson, Roy M. Harrison, William Hicks, Frank J. Kelly, Franceska Kishta, Mark R. Miller, Ian S. Mudway, Farzan Oroumiyeh, Liza Selley, Meng Wang, and Yifang Zhu Environmental Science & Technology 2022 56 (11), 6813-6835 DOI: 10.1021/acs.est.2c01072

Figure. UK Traffic-related PM2.5 by year (Source DEFRA)

What the experts have to say

DEFRA’s Air Quality Expert Group report on Non-Exhaust Emissions from Road Traffic:

"Brake wear is a major source of coarse mode metals, which contribute significantly to the oxidative potential of particulate matter, and so potentially play a major role in driving adverse health effects."

UK Organisation for Economic Co-operation and Development report (2020):

 “While electric vehicles are estimated to emit slightly less PM10 from non-exhaust sources than conventional vehicles, heavier-weight electric vehicless are estimated to emit more PM2.5 than conventional vehicles.”

UK Health Security Agency: Statement on the differential toxicity of particulate matter according to source or constituents: 2022

When discussing fleet electrification: “There remains some uncertainty as to the precise directions of change [of increased electrification], but declines in sulphate and nitrate particles seem likely, with a possible increase in biogenic secondary organic aerosol. Changes in particle composition may present an opportunity to evaluate effects of differing components upon health.”