www.emissionsanalytics.com/ news/ pollution-tyre-wear-worse-exhaust-emissions /
www.greencarcongress.com/ 2020/ 01/ 20200113-bad.html
...Oxford, 6th March 2020: Pollution from tyre wear can be 1,000 times worse than what comes out of a car's exhaust, Emissions Analytics has found. Harmful particle matter from tyres - and also brakes - is a very serious and growing environmental problem, one that is being exacerbated by the increasing popularity of large, heavy vehicles such as SUVs, and growing demand for electric vehicles, which are heavier than standard cars because of their batteries. What's more, vehicle tyre wear pollution is completely unregulated, unlike exhaust emissions which have been rapidly reduced by car makers thanks to the pressure placed on them by European emissions standards. New cars now emit very little in the way of particulate matter but there is growing concern around â€˜non-exhaust emissions'. Non-exhaust emissions (NEE) are particles released into the air from brake wear, tyre wear, road surface wear and resuspension of road dust during on-road vehicle usage. No legislation is in place to limit or reduce NEE, but they cause a great deal of concern for air quality. ...To understand the scale of the problem, Emissions Analytics - the leading independent global testing and data specialist for the scientific measurement of realworld emissions - performed some initial tyre wear testing. Using a popular family hatchback running on brand new, correctly inflated tyres, we found that the car emitted 5.8 grams per kilometer of particles. Compared with regulated exhaust emission limits of 4.5 milligrams per kilometer, the completely unregulated tyre wear emission is higher by a factor of over 1,000. Emissions Analytics notes that this could be even higher if the vehicle had tyres which were underinflated, or the road surfaces used for the test were rougher, or the tyres used were from a budget range - all very recognisable scenarios in â€˜real world' motoring. ...
...It is estimated that only 7% of PM2.5 pollution from traffic comes from tailpipe exhaust fumes at roadside sites-the rest comes from sources such as tire, clutch and brake wear, as well as the resuspension of road dust. Brake dust is the source of approximately 20% of total PM2.5 traffic pollution....