Several years ago I remember reading about a technique to prevent dust from getting into your RV while travelling down dirt roads.

I seem to remember it had something to do with opening the roof vents (one or both ? or ???) to create a pressure on the inside of the RV while travelling..... It was also effective to keep the diesel exhaust fumes from entering the travel trailer or 5th wheel. 

Does anyone know this technique ????

From a 1964 Avlon Travelcade owners manual,

"At times while traveling on extremely dusty roads, it is
advisable to leave the front roof vent open slightly.
This has a tendency to create an air pressure inside of
the trailer and prevent dust from filtering into the trailers."  
 
Don't ask me if it works I have never tried it, of course I travel dusty roads very infrequently.  If anyone can shed some light on this please do so. 
 
Flyone

Wow, you remembered that from 1964, good memory......

Thanks for the reply and info.  That's what I remebered about the technique. You had to do something with one of the vents to create the pressure and it was counter-intuitive to what I would expect to happen.

I never tried it but remembered it was in answer to someone's question about preventing diesel fumes, from the tow vehicle, entering their 5th wheel while travelling.

I can remember "way back when", travelling in the campershell of my dad's pickup while on a roadtrip.  My brother and I discovered if you opened the roof vent and poured a box of cereal, the cereal would go up to the vent and stay as we drove down the highway.   It wasn't until we stopped we discovered the other part of the experiment..... the clean up and Dad's questioning look when he saw the mess on the floor.    Oops.....

Ahhh-no I don't remember it from 1964, I remember reading it somewhere before and looked around and was able to find it again. Good story about the cereal, that may lend some credance to the theroy of positive pressure inside the rig and keeping dust and or fumes out. 
 
Flyone