Lawrence T. Dauer, PhD is a clinical physicist at Memorial Sloan Kettering Cancer Center. His clinical expertise is in Radiation Protection and Medical Health Physics. He discusses the connection between Radon and lung cancer. Radon is the second leading cause of lung cancer in the United States. Only smoking causes more lung cancer deaths.
Many people have not heard of Radon. Radon is a radioactive gas given off by soil, rock, and water. It results from the breakdown of naturally occurring radioactive isotopes in uranium buried deep underground. The US Environmental Protection Agency (EPA) classifies radon as a carcinogen because it can get into the air and increase the risk of lung cancer. People can be exposed to radon primarily from breathing radon in air that comes through cracks and gaps in buildings and homes. There are maps of areas in the U.S. that show the level of radon concentration.
The link between radon and lung cancer has been firmly established over the past four decades from studies in people and in the lab. The elevated lung cancer risk was first noticed in uranium miners, who worked in confined spaces underground for long periods. This led scientists to consider that radon exposure could be a wider problem.
“They performed studies measuring radon levels in homes, especially in areas where houses are buttoned up for heating and cooling for much of the year,” Dr. Dauer explains. “Some homes had radon levels close to some of the lower levels in the mines.” Major scientific organizations believe that radon contributes to approximately 12% of lung cancers annually in the United States. Among smokers, the increase in risk is dramatic due to the synergistic effects of radon and smoking. The EPA estimates that radon exposure increases lung cancer risk eight to nine times in smokers compared with nonsmokers.
Exactly how radon causes lung cancer is also well understood — and explains why it does not seem to contribute to other cancers. Some forms of radioactive material can be absorbed into the body and may even concentrate in the bone, but radon gas goes only to the lungs. “As radon gas breaks down, the particles lodge themselves in the alveoli, the tiny air sacs in the lungs,” Dr. Dauer says. “Or the radon gas molecules themselves attach to small dust particles, which go into the deep part of the lungs. Either way, once present, the energy they give off can damage lung cells and eventually lead to cancer.”
Home testing is recommended and it is simple and inexpensive. Test kits can be purchased at home improvement stores, hardware stores, or online for about $20 to $30. “It usually is about the size of a hockey puck and has perforated holes and charcoal inside,” Dr. Dauer says. “You open it, like you would an air freshener, leave it sitting for a few days in your house in one of the lower-level rooms, and then send it off to a lab for testing.”
Radon is measured in picocuries per liter of air (pCi/L), an indicator of radioactivity. The average indoor radon level in the United States is about 1.3 pCi/L. The average outdoor level is about 0.4 pCi/L. Both the US Surgeon General and EPA recommend fixing homes with radon levels at or above 4 pCi/L.
The process, called radon mitigation, is easier than most people think. Rather than trying to seal the house so that radon doesn’t seep in at all, the most common method diverts the radon gas from under the basement floor through a pipe to the outside — either through the roof like a chimney or through a wall to a vent. Once outdoors, the radon gas dissipates and is not a hazard.
Radon mitigation systems have become common because of the EPA’s push to inform people about the potential risks of radon,” Dr. Dauer says.
For more information visit:
National Cancer Institute: cancer.gov
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Ask your child’s school too what the Radon level is. A lot of schools do testing.