[julianeon]

I live in a part of California where the air is bad for a significant portion of the year - no less than one tenth to one quarter of the year. So opening the window wouldn’t save me from particulates & pollution - in fact, it would introduce them. The only solution for us is to not introduce them in the first place.

[kurthr]

I'd highly recommend putting together one of these very effective and inexpensive ($40?) air filters. Just taping filters together around a box fan.

https://en.wikipedia.org/wiki/Corsi%E2%80%93Rosenthal_Box

We used one them during the horrific fires with excellent effect.