It actually does happen for 26 hours in Israel one day every year. Yom Kippur.
https://www.israellycool.com/2013/09/11/the-science-is-in-yom-kippur-air-is-cleaner/
https://www.israellycool.com/2010/09/17/being-jewish-is-easy-in-israel-even-on-yom-kippur/
I do believe that, but it won't ever happen on a large enough scale unless the problem gets big enough - which is what should be avoided in the first place.