Radon in homes boosts cancer risk

Radon, a naturally occurring radioactive substance undetectable by the human senses and a major cause of lung cancer, has been confirmed as a potential health hazard in private residences in Korea, especially during the wintertime.

The JoongAng Ilbo and JTBC’s “Investigative Code J” team exclusively obtained investigative reports by the Ministry of Environment and the National Institution of Environmental Research entitled “Radon Concentration in Indoor Air in Houses Nationwide.” The investigation took place from the summer of 2010 to last spring covering 1,300 sites.

According to the investigation, in the case of detached, private residences, the radon concentration was 1.4 percent lower than the safety standard during the summer, but was 25.7 percent higher in the autumn, and 33.3 percent higher in the winter.

Radon gas concentrations are measured in picocuries per liter (pCi/l), and the safety standard for indoor radon levels is 4 pCi/l or 148 Bq, becquerel per cubic meter (Bq/m3). Any level over that amount is considered a radioactivity risk.

In Pyeongchang, Gangwon, some private residences registered a level of 1508.7 Bq, 10.2 times the safety standard. The private residences measured during the investigation all exceeded 158.7 Bq.

According to Seo Su-yeon, a researcher at the National Institution of Environmental Research, “Radon leaks from the ground and enters indoors, and in the case of private residences, because they are close to the ground and not well ventilated during the winter, the radon pollution is severe.”

Radon is a colorless, odorless and tasteless radioactive gas that is released by the breakdown of uranium and radium in the ground.

Once radon enters the atmosphere, it is diluted in the air and is of minor concern. However, when the radioactive gas gets into homes, it can pose a risk if it accumulates in an enclosed space.

When radon breaks down, it releases new radioactive elements called radon daughters, or decay products, which are solids and can stick to dust particles and other surfaces and can contribute to developing lung cancer when inhaled.

Radon poses the highest risk in the winter. Residences closest to the ground, especially basements, have the highest risk of radon pollution.

The U.S. Environmental Protection Agency estimates radon causes 21,000 lung cancer deaths per year in the United States. There is no concrete data on radon-induced cancers in Korea.

The Environmental Ministry recorded the highest concentration of radon in a town in Pyeongchang, Gangwon. The investigation team, with the aid of Yonsei University researchers, measured radon levels in 20 households. Half exceeded the standard level of radon.

An 80-year-old resident of the neighborhood whose house was recorded to have a high concentration of radon is currently undergoing chemotherapy for lung cancer.

“One person passed away from lung cancer in this town,” said a resident, “and it is common for people to suffer from lung diseases, though not necessarily lung cancer.”

“Although radon is dangerous,” said Yonsei University Professor Lee Seok-jung, “it is possible to minimize the radon level with frequent ventilation and by sealing cracks in the floor and walls.”

The Environment Ministry plans to continue to measure radon levels in 10,000 households nationwide.

By Kang Chan-su [sarahkim@joongang.co.kr]