Radon is a naturally occurring colorless, odorless, radioactive gas. It forms from the decay (break down) of the radioactive element, uranium, which is found in soil and rock, right here in Arizona. As uranium in our soil decays and generates radon gas, it moves through the soil and enter our homes through cracks and openings in the foundation into the air we breathe.
The amount of radon in the soil depends on soil chemistry, which varies from one house to the next. Radon levels in the soil range from a few hundred to several thousands of pCi/L (picocuries per liter) in air. The amount of radon that escapes from the soil to enter the house depends on the weather, soil porosity, soil moisture, and the suction within the house. Testing is the only way to know your level of exposure. Radon can have a big impact on indoor air quality.
Based on the American Cancer Society, elevated levels of radon over an extended period of time can cause lung cancer. When we breathe radon in the air and it decays (breaks down), tiny radioactive elements impact the lining of the lungs, where the radiation does damage to the lung tissue. These damaged lung cells can eventually lead to lung cancer.
The International Agency for Research on Cancer (IARC), part of the World Health Organization (WHO) has indicated there is sufficient evidence that radon and its progeny can cause lung cancer, and classifies them as “carcinogenic to humans.”
The conclusion that radon is a serious health risk is supported by the Surgeon General of the United States, the U.S. Environmental Protection Agency, the American Lung Association, the National Academy of Science, and the National Council on Radiation Protection.
Not everyone exposed to radon develops lung cancer; but as the level of radon and length of exposure increase, so do the health risks.
The EPA-recommended action level is not a safety standard. Levels below 4.0 pCi/L still represent some risk. Even outdoor air contains some radon.