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Comment by ThinkBeat | Hacker News Reader

This will come from all ground transportation sources, right? Busses, trains, trams, subways etc.

Probably the heavier the vehicle the more particles are likely to be produced?

Being on or near a train platform and you can see brake dust caked on everything. Probably dust combined with grease. It's worse looking than roads.

I’m pretty sure they grease the rails in some spots, particularly the curvy bits that are often near platforms so it would get stuck to the rails and such. Cars would put out massively more pollution but it’s more free to blow around in the wind.

I had some boxes stored in a storage cage in my apartment car park and after 6 months sitting there, they were all coated in a thick black dust. Since there was no wind or rain to move it around, it just settles and builds up.

They don't grease the cross beams on ceilings though, and those things are nasty in train stations. Same stuff you see creeping up the walls around the tracks in the subway tunnel. Not a competition though, the pollution is bad and we're all so used to it.

>Not a competition though

It is quite important to discuss exactly where the top sources of pollution are through so we can cut back on the worst sources of them to have the most impact.

I could always smell iron filings when standing on an enclosed train platform. There's definitely something floating around there.

Heavy vehicles like busses and trucks more often have drum brakes which I guess are better from a air pollution view?

drum breaks have the breaks enclosed so the particles won't be in the air

If you've ever worked on a vehicle with drum brakes, you would see the foolishness in your statement. Brake dust goes everywhere, whether it be drums or disc brakes. Older drum brakes were even more hazardous because the brake linings were built with asbestos, at least until the 1990s for US-made brake products. Aftermarket and foreign-made brake pads apparently still have asbestos in them.

I'm not too worried about this. It's an engineering problem and now that is been raised, we can find solutions.

> It's an engineering problem and now that is been raised, we can find solutions.

Engineers won't be permitted to spend any time or dollars solving this till there is a law capping particulate emissions.

Drum brakes that I've worked on often have a lot of dust in the drum. Which is a good thing because all of that dust is not in the air. But of course they are not anywhere close to being sealed.

> It's an engineering problem and now that is been raised, we can find solutions.

This should be the default attitude of society

It should at least be the default attitude on this site.

Not really. Most brake dust falls from the drums by design.

All wheeled ground transportation sources that use brakes. Legged vehicles and ground effect vehicles would not suffer from this problem, and we shouldn't necessarily assume the wheel will be the forever solution, we should not fail to dream.

From airplanes, you get the lead from their fuel

Only very small piston airplanes, and the need fuel is being phased out. Areas immediately surrounding heavily used ga airports are occasionally seeing elevated levels but it's not a particularly potent source for the public. The issue is mostly employees at the airport being exposed while fueling and performing maintenance.

why are they still using it?

They want a perfect changeover where new fuel can run in old engines. Problem is general aviation is stick in the 1950s, and dont want to have to replave their valve seats with hardened ones.

Partly because boomers, partly because the FAA is bad at their jobs.

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