World Health Organization lowers recommended action level for radon; goal is to reduce lung-cancer risk

Based on recently completed research, the World Health Organization is recommending that homeowners take action to remediate the radon level in their home if it exceeds 100 becquerels (Bq), which corresponds to 2.7 picocuries per liter (pCi/L).That's lower than the 4.0 pCi/L current action level in this country as recommended by the U.S Environmental Protection Agency.

The WHO also says that if this level can't be reached because of country-specific conditions, the action level should not exceed 300 Bq, or about 8 pCi/L. 

The WHO research, based on four years of work by 100 scientists from 30 countries, appears in the " WHO Handbook on Indoor Radon" (PDF).

The EPA has just learned of the WHO's recommendation, according to Tom Kelly, acting director of the EPA's Office of Radiation and Indoor Air. The EPA regularly reexamines its recommendations on radon and will take the WHO's advice into account but is not changing the level now. "The WHO does not say 2.7 is a safe level; there is no safe level. The EPA has said that homeowners should consider mitigation at levels of 2.0 pCi/L," says Kelly. "At levels of 4.0 pCi/L, homeowner should be very concerned. What's most important is that homeowners have their homes tested and that our message on radon is simple, clear, memorable, and actionable."
 
Radon, a radioactive gas, results from the natural decay of uranium that's present in most soils and can enter the home through cracks and holes in the foundation. Radon is a leading cause of lung cancer among nonsmokers. The WHO states that as many as 14 percent of lung-cancer cases in many countries, including the United States, are caused by exposure to radon. Smokers who live in a home with radon face an even higher lung-cancer risk.
 
Detecting radon is relatively simple and fixing the problem isn't difficult. However, as we found in our latest report on radon test kits, some kits underreported radon levels by almost 40 percent, so choosing the right one is crucial. Check out our ratings of radon test kits to find the most accurate, reliable models.

Long-term kits are more accurate because radon levels can vary from day to day. You should place the test kit(s) on the lowest occupied level of your home away from windows or vents.—Celia Kuperszmid Lehrman | e-mail | Twitter | Forums | Facebook

Essential information: Remember, radon levels can vary from one house to another in a neighborhood, so even if all surrounding homes are free of radon, you should have yours tested, especially important if you've done major structural renovations. To find a remediation contractor, contact your state radon office. Remediation will cost $800 to $2,500, depending on the radon-reduction system used and the characteristics of your home.