NEUTRAL PRESSURE
When good communication to the outdoor air exists in the basement , like open windows and doors or other big openings , the differential pressure reduces significantly . Therefore , there is not much movement between inside air and the Radon laden soil gas .
Open windows and doors significantly affect the differential pressure and also provide some dilution , which helps reduce the Radon level .
Radon & Neutral Pressure
It is interesting to know that a positive pressure equal to a few thousandths of an inch of the water column is enough to draw Radon into the house .
NEGATIVE PRESSURE
Most houses have negative pressure , which means that the pressure inside the house is lower than the outside air pressure . Negative pressure inside the building creates a vacuum that draws the outside air , including the soil gas , into the house . The negative pressure and the indoor Radon level are directly correlated . Higher negative pressure cause higher indoor Radon level , and by decreasing the negative pressure , the indoor Radon level decreases .