[dofm]

This is now quite well-studied because we have had two periods in our own lifetimes (OK I guess maybe not in the lifetimes of some HN readers!), where we have cut air pollution radically almost overnight. 9/11 and the COVID pandemic transport shutdown.

In both cases, the pan evaporation rate went up; in the case of 9/11 it went up very noticeably in a short period of time.

Essentially: clean air == less "global dimming". Whether any really recent changes like the increasingly successful rollout of electric cars is yet having an effect, I don't know.

[Wacari]

Yeah, another example is when the Internation Maritime Organization reduced the legal sulfur content limit in shipping fuel.

This reduced SO2 emissions by about 80%, which improved human health, but also caused an increase in short-term atmospheric warming.