The heat smoke and thus lowered light causes problems for crops and workers.

We don’t have a lot of research on smoke because it’s not something that we encounter frequently,” says Tim Waters, a regional vegetable specialist for WSU. “Smoke is hard to replicate in a greenhouse. We have a lot of speculation, but not a lot of fact on what smoke will do to the crop.”

At a nearby farm outside Eltopia, Wash., Alan Schreiber says he’s been having to send his 30 workers home around noon. They’re wearing masks, but even with them on, the smoke is making people sick — with tight chests, itchy eyes and dry throats.

 

https://www.npr.org/sections/thesalt/2018/08/29/642380447/as-wildfires-rage-smoke-chokes-out-farmworkers-and-delays-some-crops