air filtration isn't expensive nor hard... last generation cleaned water, perhaps we should clean the air. start small, indoors and transportation, reduce exposure simple stuff and just gotta do it.
The problem is that all the bad stuff from cars by definition is OUTIDE, where it's essentially impossible to filter besides wearing a properly fitting respirator.
Air filtration is a really great idea, but it doesn't help if you want to spend time in your own yard or open a window. Thankfully we haven't yet reached the point where we're all forced to live in hermetically sealed houses with filtered air pumped in, or where we need to wear a hazmat suit outdoors. I'd prefer to clean up the air and avoid excessively or needlessly polluting it further so that we can enjoy it rather than having to living in a bubble.
We can't filter our way out of this problem. If we can build cars better to reduce their harms and there are ways to place particle collectors near streets and houses to reduce the environment impacts of traffic I'm all for it.
