Study: Radon Risk in Homes UnderestimatedJun 7, 2002 | Healthscout The health risk posed by residential radon exposure may be 50 percent higher than indicated by previous studies, say University of Iowa researchers.
"I think the risk posed by radon is really underestimated," says R. William Field, a research scientist at the University of Iowa College of Public Health and the lead author of a study just published in the Journal of Exposure Analysis and Environmental Epidemiology.
Radon is a naturally occurring, odorless, tasteless, and colorless radioactive gas produced by the breakdown of radium in soil, rock, and water. It seeps out of the soil and into homes. Long-term exposure to the gas in a home is associated with increased lung cancer risk.
Field and his colleagues examined several exposure assessment methods used in previous residential radon studies that were done in North America, Europe and China. Those epidemiological models looked for associations between radon exposure and lung cancer rates.
The Iowa researchers compared those models to a more comprehensive exposure model that assesses the health risk by measuring radon levels in specific areas of a home and how much time the residents spend in those areas.
All the exposure models were assessed using the same study population. The models used in previous studies all produced risk estimates that were about 50 percent lower than the more comprehensive model used by his team, Field says.
"To really get a good radon dose assessment, you have to perform the study on the individual level," Field says.
For example, the basement of a home may have high levels of radon -- but that's not much of a health threat if the occupants don't spend much time there, he says. But if a living room has high radon levels and it's the focus of family activity, then the health risks will go up.
"If you are really concerned about what are the levels you're being exposed to and what kind of risk does that put you at, our study indicates that you should really be testing your living areas of your home and your bedroom. You spend six to 10 hours a night there, so that's a significant amount of your time per day," Field says.
A U.S. Environmental Protection Agency (news - web sites) (EPA) official says Field's research is unique and valuable for helping make residential radon risk estimates more precise.
"His research supports that radon risks are at least as big as we thought," says David Rowson, director of the Center for Healthy Buildings, part of the EPA's Indoor Environments Division.
"The growing body of data on radon risk continues to support the need for all homes in America to be tested for radon and for elevated levels to be fixed," Rowson adds.
The EPA says 15,000 (or nearly 10 percent) of all lung cancer deaths in the United States are attributable to radon.
Smokers are at higher risk of developing radon-induced lung cancer. There's no evidence to link radon to other respiratory diseases such as asthma, the EPA says.
Although radon levels may be higher in some areas of the United States, it's a potential problem in every state. Local geology, construction materials, and how an individual house is built can affect indoor radon levels. So don't assume that you have a problem even if your next-door neighbor does.
Experts advise that the only way to know for certain whether your home has high radon levels is to have it tested.
The EPA recommends that homes be fixed if the occupants' long-term radon exposure averages 4 picocuries per liter (pCi/L). The average indoor radon level in the United States is 1.3 pCi/L.
What To Do
You can buy radon detecting devices or hire a qualified radon tester to check your home's radon levels.
Most radon repairs cost between $800 to $2,500. They may include installing underground pipes and an exhaust system to expel the radon, or sealing cracks and other openings in floors and walls.