Particulate emissions from electric cars as bad as conventional – due to more tyre and brake wear

Date added: 12 February, 2017

While electric vehicles are a welcome technology, enabling a cut in local air pollution from diesel and petrol cars and vans, (as long as the electricity they use has been sustainably produced) they are not wholly a “silver bullet” solution.  A new study shows that much of the particulate air pollution in cities comes from from vehicle tyres and brakes. There is a positive relationship between vehicle weight and these non-exhaust emissions – the heavier the vehicle, the more wear on tyres and brakes, and road surface wear and resuspension of road dust. As electric vehicles tend to be around a quarter heavier, for the equivalent size, than their conventional equivalent internal combustion engine counterparts they produce more of this pollution. Therefore electric vehicle PM emissions – overall  – are comparable to those of conventional vehicles.
The study found that these non-exhaust sources account for around 90% of PM10 and 85% of PM2.5 from traffic.
They conclude: “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.”  Heathrow is pinning its hopes for cutting air pollution on more use of electric vehicles.
.
Tweet

Non-exhaust PM emissions from electric vehicles

by Victor R.J.H. Timmers (University of Edinburgh, Edinburgh EH8 9YL, UK)

and Peter A.J. Achten (INNAS BV, 15 Nikkelstraat, 4823 AE Breda, Netherlands)

Highlights

 -
A positive relationship exists between vehicle weight and non-exhaust emissions.

 – Electric vehicles are 24% heavier than their conventional counterparts.

 – Electric vehicle PM emissions are comparable to those of conventional vehicles.

 – Non-exhaust sources account for 90% of PM10 and 85% of PM2.5 from traffic.

– Future policy should focus on reducing vehicle weight.

Abstract:

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. PM2.5 emissions were only 1e3% 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. Nonexhaust emissions already account for over 90% of PM10 and 85% of PM2.5 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. © 2016 Elsevier Ltd. All rights reserved.

.

Conclusions:

6. Air quality in numerous places in Europe does not reach EU standards. As a result, many people experience adverse health effects due to very high concentrations of PM. Traffic is one of the major sources of ambient PM, especially in urban areas. The EV has been proposed as a solution to air pollution. Therefore, many countries are incentivising alternative fuel vehicles such as EVs.

Vehicle weight was expected to play a role in emission factors, since each of the non-exhaust emission sources is affected by weight. Several studies provided evidence that there is indeed a positive correlation between weight and non-exhaust emissions. However, more research is needed into the exact impact additional weight has on emission factors. EVs were found to be 24% heavier than equivalent non-electric models. Based on the available data, we calculated that EVs produce the same amount of PM10 as average conventional vehicles. EVs have slightly lower PM2.5 emissions, emitting 1e3% less than ICEVs, on average. However, these differences are likely to disappear completely as exhaust emission standards become even stricter.

Therefore, EVs are not likely to have a large impact on PM emissions from traffic. Non-exhaust sources account for more than 90% of PM10 and 85% of PM2.5 emissions from passenger cars, and this proportion is likely to increase in the future as vehicles become heavier. Policy so far has only focused on reducing PM from exhaust emissions. Therefore, future European legislation should set non-exhaust emission standards for all vehicles and introduce standardised measurement methods. In addition, it is recommended that EV technology such as lightweight car bodies and regenerative brakes be applied to ICEVs, and incentives provided for consumers and car manufacturers to switch to less heavy vehicles.

http://www.soliftec.com/NonExhaust%20PMs.pdf

.

Vehicles emit PM through their exhaust and through non-exhaust sources, such as tyre wear, brake wear, road surface wear and resuspension of road dust

See also

.

and

HEATHROW WINS ENVIRO AWARD FOR ITS FLEET OF ELECTRIC VEHICLES

26.10.2015

Posted: Sunday, February 12th, 2017. Filed in Air Quality, News about Airports, Recent News.