[simonsarris]

Sure. There's: http://www.soliftec.com/NonExhaust%20PMs.pdf (2016)

Study 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

Part of this is that we already spent a lot of deliberate effort on reducing emissions from engines. As the study notes:

> Before the introduction of air quality standards, exhaust emissions used to be a major source of PM, especially for diesel cars (Miguel et al., 1998). Since then, PM emission standards for vehicle exhausts have become increasingly strict and now all new diesel passenger cars are fitted with a diesel particulate filter (DPF). Bergmann et al. (2009) found that DPFs are very effective at reducing PM emissions, lowering the emitted mass of PM by 99.3%