Our Mh is pretty tight. The air conditioners recirculate air inside the RV. Going down the road we get a lot of dust and everything else through the dash air intake to the ac
Newer models may have intake filter. Bad smokey air in the ac an air purifier sound like the better approach. here lately we've seen a number of ads for them on tv. May have something to do with the fires, I dunno.
Just a thought: one of your roof fans, an air filter taped over one and the fan control turned to pull air in. Good filter might catch everything and positive air pressure keep air with smoke etc from getting in anywhere else. I have not tried it and don'tknwo the percentages, so to speak.
