Radon in homes poses significant health risks primarily because it is a radioactive gas that can accumulate indoors without any color, smell, or taste, making it undetectable without testing. The most serious health risk associated with radon exposure is lung cancer. Radon gas originates from the natural decay of uranium in soil, rock, and water, and it can seep into homes through cracks in foundations, gaps around pipes, and other openings. Once inside, it can build up to dangerous levels, especially in poorly ventilated areas like basements and crawl spaces.
When radon gas is inhaled, it decays into radioactive particles that lodge in the lungs. These particles emit radiation that damages lung tissue at the cellular level, causing mutations that can lead to lung cancer over time. This process is gradual, and lung cancer typically develops years, often decades, after exposure begins. Radon is recognized as the second leading cause of lung cancer after smoking and is the leading cause among non-smokers. The risk is especially high for smokers exposed to radon, as the combination multiplies the likelihood of developing lung cancer by about ten times compared to non-smokers without radon exposure.
The risk from radon exposure is measured in picocuries per liter (pCi/L) or becquerels per cubic meter (Bq/m³). The Environmental Protection Agency (EPA) recommends action to reduce radon levels if they exceed 4 pCi/L (approximately 148 Bq/m³). At or above this level, the risk of lung cancer is comparable to smoking a pack of cigarettes daily. In the United States, about 1 in 15 homes has radon levels above this threshold, and radon exposure is estimated to cause around 21,000 lung cancer deaths annually.
Other respiratory diseases such as asthma or chronic bronchitis have not been definitively linked to radon exposure. Children and adults appear to have similar susceptibility to radon-induced lung cancer, although children’s higher breathing rates and developing lungs might suggest some increased vulnerability, but evidence remains inconclusive.
Radon exposure does not cause immediate symptoms, so people living in homes with high radon levels often remain unaware of the danger until health effects manifest years later. Testing is the only way to detect radon, and it is recommended for all homes, especially in areas known for elevated radon levels. Testing is simple and affordable, using either short-term or long-term test kits or continuous radon monitors.
If high radon levels are found, mitigation techniques can effectively reduce radon concentrations indoors. These include methods such as sub-slab suction (venting radon from beneath the foundation), sealing cracks and openings, improving ventilation, and installing systems that pressurize or ventilate the home to prevent radon entry or remove it once inside. New homes can be built with radon-resistant features to prevent accumulation from the start.
In addition to lung cancer, some studies have suggested that chronic radon exposure might contribute to other lung conditions like emphysema, pulmonary fibrosis, or respiratory lesions, but these links are less well established and require further research.
Overall, the health risks of radon in homes are serious because of its invisible nature and its strong association with lung cancer, particularly among smokers and those exposed to high radon levels over long periods. Awareness, testing, and mitigation are key to protecting health from this silent hazard.