Radon is a naturally occurring, radioactive gas that is both odorless and colorless, making it undetectable by human senses. It forms from the natural breakdown of uranium found in nearly all soils and rocks. This gas poses a serious health concern, particularly when it accumulates in enclosed spaces such as homes, where it can build up to elevated concentrations without residents’ knowledge.
Understanding Radon in Your Home
Radon originates deep within the earth as uranium in soil, rock, and water naturally decays. As this radioactive gas is produced, it moves up through the ground and can enter homes through various openings. Common entry points include cracks in foundation walls and floor slabs, construction joints, gaps around service pipes, floor drains, and sump pits. Any home, regardless of its age, design, or whether it has a basement, has the potential for a radon problem. While radon from soil gas is the primary source, it can also enter a home through well water, though this is less common.
How Exposure Duration Affects Risk
The health risk associated with radon exposure is cumulative, meaning it builds up over time. While short periods of exposure to high radon levels can contribute to this risk, it is primarily long-term, continuous exposure to elevated concentrations that significantly increases health concerns. Agencies like the U.S. Environmental Protection Agency (EPA) have established an action level of 4 picocuries per liter (pCi/L), recommending that mitigation steps be taken if radon levels meet or exceed this concentration.
Health Risks and Latency
The primary health risk linked to radon exposure is lung cancer. When radon gas decays, it produces tiny radioactive particles. These particles can become trapped in the lungs upon inhalation, where they continue to break down and release small bursts of energy. This energy can damage the DNA in lung tissue cells, potentially leading to the development of cancerous cells over time.
The development of lung cancer from radon exposure typically has a long latency period, meaning that the disease may not manifest until many years after the initial exposure, often ranging from 5 to 25 years. Radon is recognized as the second leading cause of lung cancer overall and is the leading cause of lung cancer among non-smokers.
Testing and Reducing Radon Levels
Determining radon levels in a home is straightforward and involves testing. Both short-term and long-term radon tests are available. Short-term tests typically measure radon for 2 to 90 days and are useful for initial screenings, providing quick results. However, long-term tests, which measure radon levels over 90 days or longer, offer a more accurate average of exposure by accounting for daily and seasonal fluctuations.
If elevated radon levels are detected, mitigation systems can effectively reduce concentrations. The most common and effective method is active soil depressurization, also known as sub-slab depressurization. This system uses a fan and a vent pipe to pull radon from beneath the house’s foundation and safely exhaust it outside, preventing it from entering the indoor air. Sealing cracks and other entry points in the foundation also helps to improve the efficiency of these systems.