I think that instead we will see cleaner air in cities since the economics of electric/hybrid cars will win, especially in city traffic. This trend can already be seen in SF where zero-emission hybrids and electrics make up a decent percentage of the traffic.
Personal automobiles are part of the problem. Perhaps not the biggest problem but a big one in cities.
Emphasis added. https://en.m.wikipedia.org/wiki/Exhaust_gas
https://www.bts.gov/content/estimated-national-average-vehic...
This gives actual figures for PM2.5 emissions from exhaust, brake wear, and tire wear per mile for both gasoline and diesel vehicles.
There is an argument about how much EV's would reduce PM2.5. The above shows things were a lot worse 20 years ago. And current gasoline cars produce 0.008gm/mile PM2.5 from exhaust and 0.003 and 0.001 from brakes and tire wear.
That says to me that EV would still reduce emissions a lot. One can assume that brake wear is half that of a gasoline powered car. So you go from 0.011gm/mile for gas. To probably 0.003 for EV's.
Electrifying diesel trucks is a huge win.
Citation needed. The whole economic and environment footprint of electric vehicles in relation to their efficieny is rather bad. The future would the CNG but something is holding it back.