How much Radon is “too much” and what is the risk?
Although you may still occasionally hear remarks such as “radon is a hoax!” or “some radon is good for you,” there is no scientific doubt that exposure to high radon levels can cause lung cancer.
Radon is measured in pico (peeko) curies and the US EPA considers 4.0 pCi/L (pico curies perliter of air) as an “action level,” above which measures should be taken to reduce exposure to “as low as reasonably achievable.” Living in a home with 4.0 pCi/l is the equivalent of each family member smoking ½ pack of cigarettes a day. For this reason the World Health Organization lowered its recommended action level from 4.0 to 2.7 pCi/l.
The state of Ohio is classified as a Zone 1 Radon Area. This means that the average home in the state exceeds the EPA action level of 4.0 pCi/l.
Below is a risk table taken from EPA Publication 6604J, “Air and Radiation.”
Need more information?
Much more information is now being done to see if exposure to radon gas may cause cancers other than lung cancer. This research is centered around the p53 tumor suppressor gene.
There is evidence to suggest that damage to this important gene due to radon exposure can be the link to other cancers. In fact, there is evidence that mutated genes can be passed on to future generations, explaining why some families seem to be susceptible to certain kinds of cancers.
For more information, check out these web sites.
Article on p53 tumor suppressor gene
Watch our Community Awareness Video from the American Association of Radon Scientists and Technicians
Types of Mitigation Strategies
Any home can have a radon problem, regardless of the foundation type. All mitigation strategies encompass methods to divert soil gas from the soil around your house to a solid PVC pipe and exhausting that air to the outside with a fan.
Sump and drain tile depressurization
This strategy begins with sealing openings in the basement floor (including special covers for sump pits, sealants, etc.). A PVC pipe (usually 4” in diameter) is inserted through an opening in the sump cover or a hole bored through the concrete floor and runs to a point outside the house where a fan runs continuously, sucking air from under the basement slab.
Crawl Space sub-membrane depressurization
This strategy begins with a special “radon barrier” installed in the crawl space and attached to the foundation walls. Similarly, a PVC pipe is connected to a section of perforated pipe beneath the radon barrier. The pipe then runs to the outside of the house where a fan is mounted and runs continuously sucking air from beneath the radon barrier.
For homes built on a solid slab of concrete, one or more 4” holes are bored through the slab (usually hidden in interior closets). A PVC pipe is then inserted in the opening and rises to the attic space above where a fan is attached. The vent stack then exits the house through the roof and is properly flashed to avoid any possible leaks. This fan runs continuously and sucks the air from beneath the slab.