How does Radon enter a home?

Radon, because it is a gas, is able to move though spaces in the soil or fill material around a home's foundation. Some homes tend to operate under a negative pressure - this is especially true in the lowest portions of the home and during the heating season. This negative pressure acts as a vacuum (suction) that pulls soil gases, including radon, into the lower level of the structure. Some causes of home vacuum are:

• Heated air rising inside the home (stack effect).
• Wind blowing past a home (downwind draft effect).
• Air used by fireplaces, wood stoves, and furnaces (vacuum effect).
• Air vented to the outside by clothes dryers and exhaust fans in bathrooms, kitchens, or attics (vacuum effect)

Radon can enter a home through the floor and walls -- anywhere there is an opening between the home and the soil. Examples of such openings include dirt floor crawl spaces, unsealed sumps, cracks in slab-on-grade floors, utility penetrations, and the tiny pore spaces in concrete block walls. A basement, of course, provides a large surface area that contacts soil material.

Why is radon important?

The U.S. Environmental Protection Agency estimates that each year 21,000 people die of lung cancer as a result of being exposed to elevated levels of radon. Radon is the second leading cause of lung cancer for smokers and the leading cause of lung cancer for non-smokers.
Although radon is present throughout the environment, radon levels indoors are generally higher which increase the risk of cancer.