Great point about the filter effect, Kat. I routinely now include the wind screen when I clean the car, and it is surprising how much black dust comes off of it.
Also with you on the windows up - my earlier comment may have been misleading. I only go top down / windows up when 1) it's really cold, like below 50, 2) I'm on the highway, extended time at speed above 60, 3) on the phone I'll sometimes roll them
Up to reduce traffic noise.