[steelrat1 (OP)]

OK  the news today was about a coroner has ruled that air pollution contributed to the death of a nine-year-old girl in the first case of its kind in the UK. we hear about car exhaust pollution, but can the real reason be tyres? Some 5.8 grams per km of harmful particles produced by tyres during driving due to wear, Particulate matter is microscopic solids or liquid droplets that can be inhaled and exposure to this type of pollution can affect both your lungs and your heart.
Measurements found that 5.8 grams per kilometre of harmful particles are emitted by tyres as they wear when a car is being driven.
That compares to 4.5 milligrams per kilometre produced from exhaust pipes.
How come this isn't being addressed?  Also shoe trainers are made from problematic materials including nylon, synthetic rubber and plastic they wear down creating the same problematic particulates into the air the same way, so are we blaming all onto just one area of concern when we should be addressing the bigger picture here?

[alancalverd]

Average car tyre has about 3000 g of rubber. Multiply by 4, 12000 g per car. Divide by 5.8 gives you  2000 km wear to zero.

I drive like a lunatic and get 40,000 km before replacing at the legal limit, with more than half of the rubber still in  place.

Something wrong somewhere.

[steelrat1 (OP)]

These are not my figures, but found ones,  still it's a problem or not a problem?  This is the question,  not having enough information / data.on this subject. should this be taken into account with air pollution?

[alancalverd]

It's always a good idea to begin with the obvious truth.

My calculation gives 0.3 gram per km, a fair bit of which sticks to the road surface. Being dense and nonhygroscopic, I'd expect most of the rest to settle on the road or get washed down by rain.

Then we have to decide what proportion of what is left in the air gets into people's houses, how much of that gets into their lungs, and what justifies the word "harmful".

The particular and very sad case in today's papers concerned a known asthmatic. Asthma is an idiosyncratic allergic response to a stimulus that would not cause problems for the majority of people. There's a limit to what you can prohibit for the protection of asthmatics: you might ban smoking in public places, but we need grass pollen to feed ourselves! Given that maybe 10% of the population is asthmatic, Ella's case must be regarded as exceptional since around 30,000 other people live or work within 30 m of the same road, which is itself unexceptional for London.

The statistics of asthma are interesting. In the UK it affects significantly more boys than girls. In the USA it's the other way around. But our demographics are very similar.

[Slickscientist]

Plastic "'bags for life" also have the same problem. Have you ever noticed, some of the green bits on an Asda bag have white lines/patches in them? This is the evidence. Because of repetitive use, microplastic sheds off, and because the top layer is dyed green when shed, it will expose the white plastic underneath.

[alancalverd]

The 1662 version of the Book of Common Prayer

earth to earth, ashes to ashes, dust to dust

So if you get the fossilised or liquefied corpses of our ancestors out of the ground and turn them into plastic (or artificial rubber) they will surely return in time.

[Slickscientist]

A very long time though.