Radon is a naturally occurring, invisible, odorless, and tasteless radioactive gas that comes from the natural decay of uranium found in nearly all rocks and soils. This gas can seep from the ground into homes and other buildings through cracks and other openings, accumulating indoors. Radon is considered a leading cause of lung cancer for non-smokers and is the second leading cause of lung cancer overall.
How Radon Leads to Lung Cancer
Radon gas itself is not the direct cause of lung damage; its decay products pose the threat. As radon atoms spontaneously decay, they release radioactive particles known as radon progeny. These progeny are tiny, solid particles that attach to dust and other airborne particles, making them easily inhaled.
Once inhaled, these radioactive particles deposit onto the cells lining the airways within the lungs. There, they emit alpha radiation, which damages DNA within lung cells. This cellular damage can lead to genetic mutations. Over time, the accumulation of these mutations can disrupt normal cell growth and division, ultimately leading to the development of lung cancer.
Key Factors Influencing Your Risk
The concentration of radon in a building is a primary determinant of risk; higher levels mean greater exposure to radioactive decay products. Radon levels indoors can vary significantly, ranging from 10 Bq/m³ to over 10,000 Bq/m³, while outdoor levels are much lower, around 5 to 15 Bq/m³. This variability underscores why individual measurements are necessary, as a neighbor’s test result cannot accurately predict your risk.
The duration of exposure also plays a significant role in cumulative risk. Long-term exposure to elevated radon levels increases the probability of developing lung cancer. Damage to lung cells accumulates over time, making cancerous cell development more likely.
Smoking status profoundly influences the risk of radon-induced lung cancer due to a synergistic effect. Smokers exposed to radon face a significantly higher risk than non-smokers or smokers not exposed to radon. For instance, smokers are estimated to be 25 times more at risk from radon than non-smokers.
Quantifying the Risk of Lung Cancer
The risk of lung cancer from radon exposure is quantified using picocuries per liter (pCi/L) or becquerels per cubic meter (Bq/m³). One pCi/L is equivalent to 37 Bq/m³. The risk of lung cancer increases proportionally with increasing radon exposure.
For individuals who have never smoked, exposure to an average indoor radon level of 1.3 pCi/L carries a 2 in 1,000 chance of lung cancer. At a higher radon level of 4 pCi/L, the lifetime risk of radon-induced lung cancer for never-smokers is approximately 7 per 1,000. If the exposure increases to 10 pCi/L, the risk for never-smokers rises to about 18 per 1,000.
The risk is substantially higher for smokers. At a radon level of 1.3 pCi/L, a smoker has a 20 in 1,000 chance of dying from lung cancer. When exposed to 4 pCi/L, the lifetime risk for ever-smokers is around 62 per 1,000. At 10 pCi/L, this risk escalates to about 150 per 1,000 for ever-smokers. Overall, radon is estimated to cause between 3% to 14% of all lung cancers in a country, with approximately 21,000 lung cancer deaths attributed to radon each year in the United States, including about 2,900 deaths among people who have never smoked.
Reducing Your Exposure and Risk
Since radon is undetectable by human senses, testing homes for its presence is the only way to determine exposure levels. Both short-term and long-term testing kits are available, with long-term tests providing a more accurate average of radon levels over time. It is recommended to test your home, especially if you live in an area with known elevated radon potential.
If testing reveals high radon levels, mitigation techniques can effectively reduce the concentration. Sub-slab depressurization systems are a common and effective method, drawing radon from beneath the house and venting it safely outside. These systems create a vacuum that prevents radon from entering the living space.
For accurate testing and effective mitigation, it is advisable to consult certified radon professionals. These experts can assess the situation, recommend suitable solutions, and ensure correct installation of mitigation systems. Taking these steps can significantly reduce your exposure and risk of developing lung cancer from radon.