[zahma]

Which health concerns, though? It's not exactly easy to isolate cause and effect. I do not have comparable research into New York and pollution, but you won't convince me that it is safe to inhale elevated levels of PM2.5. That stuff goes straight into your blood and can transition the blood-brain barrier.[1]

Moreover, our bodies did not evolve to eliminate combustion products and micron-sized scraps of rubber and asphalt. In this case where evidence is absent, it is more than prudent to assume the worst case: no amount of pollution is good for us. In the same vein, we know that poly-aromatic hydrocarbons (PAHs) are carcinogenic, but does that mean we do not eat charbroiled steak? Of course not, but par for the course would be smoking a cigarette and introducing a shitload more carcinogens directly into our blood.

All of that is to say that we can probably tolerate and eliminate a low-level of exogenous pollutants entering our body, but sustained intake of pollution surely spells disaster. Then again, something's going to kill you, so pick your poison -- literally.

(Not exactly the damning evidence you're looking for, but the study below asserts causality between exogenous particulate matter infiltrating the CNS and neurological and behavioral disorders, including Alzheimer's-like symptoms and cognitive dysfunction in adults and children alike.)

1-https://www.pnas.org/doi/full/10.1073/pnas.2117083119