Cars and Drivers

Electric Cars Pollute More Than Gas-Powered Ones?

Douglas A. McIntyre

Published: May 16, 2016 9:45 am

Last Updated: January 13, 2020 8:01 am

When it comes to air pollution, vehicle weight is more important than engine type. That undercuts the claims of many electric car makers that their vehicles are 100% good for the environment.

The news is not particularly good for Tesla Motors Inc. (NASDAQ: TSLA) and the army of other manufacturers racing to get into the electric car business. A study done by Victor Timmers and A. J. Achten at the University of Edinburgh, results of which ran in the journal Atmospheric Environment, take into account much more than engine emissions alone. A heavy car has disadvantages over a light one, to some extent because of the wear it puts on roads.

In complex language, the study states:

Particulate matter (PM) exposure has been linked to adverse health effects by numerous studies. Therefore, governments have been heavily incentivising the market to switch to electric passenger cars in order to reduce air pollution. However, this literature review suggests that electric vehicles may not reduce levels of PM as much as expected, because of their relatively high weight. By analysing the existing literature on non-exhaust emissions of different vehicle categories, this review found that there is a positive relationship between weight and non-exhaust PM emission factors. In addition, electric vehicles (EVs) were found to be 24% heavier than equivalent internal combustion engine vehicles (ICEVs). As a result, total PM₁₀ emissions from EVs were found to be equal to those of modern ICEVs. PM_2.5 emissions were only 1–3% lower for EVs compared to modern ICEVs. Therefore, it could be concluded that the increased popularity of electric vehicles will likely not have a great effect on PM levels. Non-exhaust emissions already account for over 90% of PM₁₀ and 85% of PM_2.5 emissions from traffic. These proportions will continue to increase as exhaust standards improve and average vehicle weight increases. Future policy should consequently focus on setting standards for non-exhaust emissions and encouraging weight reduction of all vehicles to significantly reduce PM emissions from traffic.

The conclusion? Weight matters.