Radon is an invisible, unscented gas that can inaudibly accumulate in your home, posing a significant health risk. As the second leading cause of lung cancer in the United States, every homeowner should understand what radon is and what could cause its levels to spike in a house. Below, we’ll explain the things that can affect radon levels in your home, from its foundation to the local geography.
1. Soil Composition Around Your Home
The primary source of radon is the natural decay of uranium found in nearly all soils and rocks. The specific composition of the soil beneath and around your house plays a major role in determining your home’s potential radon levels.
For instance, soils rich in granite, shale, or phosphate contain higher concentrations of uranium, which in turn produce more radon gas. This gas can then seep into your home from the ground. The permeability of the soil also matters; radon travels more easily through loose, sandy, or gravelly soil than it does through dense clay.
2. Cracks in the Foundation and Walls
Your home’s structure is the main barrier against radon entry. However, small cracks and openings can provide a direct pathway for the gas to enter. Common entry points include cracks in the foundation slab, gaps around service pipes, construction joints, and even small pores in concrete walls.
Radon gas from the surrounding soil can seep into the house through these openings. Regularly inspecting your basement or ground floor for any visible cracks and sealing them promptly will reduce potential entry points for this harmful gas.
3. Local Geology and Radon Hotspots
Another thing that can affect radon levels in your home is its geographical location. The U.S. Environmental Protection Agency (EPA) has identified certain regions across the country as radon “hotspots” due to their underlying geology. These areas have higher natural uranium deposits in the ground and are more likely to elevate indoor radon levels.
You can consult the EPA’s Radon Zone Map to see if your home resides in a high-risk area. However, it’s important to remember that even homes in low-to-moderate risk zones can have high radon levels, making testing essential for everyone.
4. Ventilation and Air Pressure
The airflow and air pressure within your home can dramatically influence radon concentrations. A sealed, modern home might trap radon inside, allowing it to build up to dangerous levels. Even the wind can affect radon levels, especially if your home is a walk-out, built into a hillside, or on a hilltop.
Conversely, homes with poor ventilation can also create a “stack effect,” where warm air rises and escapes through the upper levels, creating a slight vacuum in the lower levels. This negative pressure can actively pull radon gas from the soil into your basement or ground floor.
Know Your Home’s Radon Levels
Since you cannot see or smell this dangerous gas, the only way to know for sure if your home has elevated levels is to test for it. Affordable and easy-to-use test kits are widely available.
If your home’s radon level is found to be 4 pCi/L or higher, the EPA recommends acting immediately. Contact a certified radon mitigation professional to discuss the best solutions for reducing radon levels in your home.