I've thought of putting filters on the dash intakes outside like the environment filters in our cars. I couldn't get up under the front of the capto see what would be required.
We were getting a lot of dust and dirt from where the Dealer cut large holes under the shower area. Factory fixed those and it cut a whole lot of it out plus added t heating and cooling efficiency.Once you could make a housing for filters replacement should be easy. there is wide variety of filters, out there.
The positive pressure from vents on top should work fine with a max air or something to keep wind from blowing the covers of vent fans off going down the road.
Surprised someone hasn't come up with a product.
Lots or RVers might be interested.
