I can't really work it out but a type of carbon particle, carbon black, is used predominantly in the manufacture of tyres. I would not mind betting that this, from tyre wear, is a significant addition to airborne fine carbon particles in the cities.
A recent research in Germany has found that only ca. 7% of small particulates are caused by Diesel engines, most of it older ones which are Euro 4 or less). More is produced by tyre wear and brake abrasion. But most of the dangerous small particulates are already on the tarmac and get whirled up again by driving.
(In southern European countries streets in cities are cleaned often by water spraying vehicles every morning or evening. The research says that this treatment would reduce the amount of particulates dramatically in our cities as well.)
The survey also states that most of PM-10 and PM-2,5 you breathe are close to or in a subway station, again caused by brake abrasion of the train brakes.
I´m not the biggest fan of Diesel engines but what the study means is, that the Diesel engines are not so dominantly influencing the measurements.
The politicians do NOT like the outcome of this serious study, nevertheless they have found a scapegoat which gives reason to milk the car drivers/ tax payers or to forbid driving certain kind of cars.
What is even more frightening, the politicians could have some more scapegoats in reserve. For example they could introduce a tyre tax for all vehicles, orientated towards the tyre width.
