Anywhere in the US west of Texas and most of Canada.

I don't think the east coast escapes, they got slammed this year by Canadian wildfire smoke IIRC.

Infectious particles? In most of USA and Canada? I don't believe you.

I'm talking about smoke, I don't even know what an "infectious particle" is.

Me neither, and that's why I asked, but it apparently offended the HN commentariat.

Yes, there are viruses in USA & Canada.