Oh, sure, but again the CO, NOx, SOx and most of the unburnt hydrocarbons in gasoline-fueled vehicle exhaust are not particles (they're gasses) and are not removed to any significant degree by a HEPA filter.
In the US, diesel cars are rare, and I would guess that the non-diesel cars in the US produce very little in the way of particulate pollution. Am I wrong about that?
That's why I used the qualifier "gasoline-fueled": the particulates are coming mostly from _diesel_ engines.
(I didn't belabor that point earlier because I assumed that people here would already know that because the VW diesel-emissions cheating scandal was such a big story.)
During a busy commute in a major US metro area, the vast majority of the vehicles on the road are gas-powered (because a large fraction of trucks will avoid busy commutes). I realize the situation is different in Europe where diesel-powered cars are much more common.
In the US, diesel cars are rare, and I would guess that the non-diesel cars in the US produce very little in the way of particulate pollution. Am I wrong about that?