The European Transport Research Review (ETRR), a peer-reviewed open access journal publishing original high-quality scholarly research and developments in areas related to transportation science, technologies, policy and practice, has published a study that compares the ozone-creation effects of vehicle fuels: petrol, diesel, Autogas and electricity (the latter in the United Kingdom). The study finds that ozone impacts of electricity are by far the highest, while the LPG has the lowest.

“For humans, elevated levels of ambient ozone cause eye and respiratory irritation, indicated by symptoms such as cough, throat dryness, eye and chest discomfort, thoracic pain and headache. Lung function is also reduced. Short-term (acute) effects of ozone exposure are undisputed. High ozone concentrations cause the above afflictions, which lead to increased hospital admissions and sometimes to death. Moreover, ground-level ozone is a significant contributor to global warming and it generates about one-fourth the warming of carbon dioxide,” reports the study.

“Considering tailpipe emissions only, gasoline’s and LPG’s per-kilometre ozone impact is 44–88% of diesel’s, while LPG’s is slightly lower than gasoline’s. If fuel production and tailpipe emissions are added together, the liquid fuels generate 48–80% of electricity’s impact, i.e. the electric car’s ozone impact is highest. The liquids’ ozone-impact rankings are the same as for tailpipe only, from most to least: diesel, gasoline, LPG,” adds Eric Johnson, author of the ETRR’s research.

Changing the fuel/energy type of a passenger car changes its emission inventory, so this could be a useful policy in combating ozone, i.e. governments could encourage some fuels/energies and discourage others. Based on the results, a priority ranking of the main types, from best to worst in the UK, is: LPG, gasoline, diesel and battery electric.

For electric, this ranking will vary in other regions, depending on the emissions of the power-generation grid. For the liquid fuels, the rankings are valid for Europe and North America in general. Impact assessment of ozone is complex, because the chemistry of its formation is complex. This complexity is only partially incorporated in existing impact assessment methods.

You can access the complete study here.