It is insane how we (as a society) have been so blind on this issue. In many countries, people have been debating why crime rates rose sharply from the 60's to the 90's. The explanation may have been simply that airborne lead particles caused brain damage in kids. In the 80's and 90'l leaded gasoline was phased out in most of the Western world so there is a clear temporal correlation between the crime wave and lead particles.
An euphemism for brain damage is "cognitive defects" but it is of course the same thing. Now imagine someone caused brain damage to your children (for example by causing a head trauma), would you be ok with that? Probably not. Not even a very small brain injury would be ok, but millions of cars doing the exact same thing, no problem!
This is pretty interesting, since the effect is so big.
I did a bit of reading and it looks like the best thing to do is to run an indoor air filter and have indoor plants that are effective at absorbing CO2 with indoor lighting[1] (not all are!).
Unfortunately recent research indicates plants aren't great at removing general particle pollution though.
An euphemism for brain damage is "cognitive defects" but it is of course the same thing. Now imagine someone caused brain damage to your children (for example by causing a head trauma), would you be ok with that? Probably not. Not even a very small brain injury would be ok, but millions of cars doing the exact same thing, no problem!