by Oyvind Birkenes
A naturally occurring substance, radon is an odorless, colorless gas found in buildings all over the world. It is also poisonous—according to the U.S. Environmental Protection Agency (EPA), radon is estimated to cause 21,000 deaths per year in the United States in the form of lung cancer and other health problems. It is generally recommended people conduct radon testing before purchasing a new home, but it is just as important for nonresidential buildings to be tested and mitigated to ensure high indoor air quality (IAQ) for those inside.
Radon is a radioactive gas that forms because of the decomposition of uranium in the earth’s crust. This process from uranium to radon takes several thousand years, but it speeds up at the later stages, continuing to break down into dangerous isotopes, such as polonium, in a matter of days. Radon and polonium emit alpha-particles that damage lung tissue and DNA, which can lead to cancer over time.
Radon is a problem found throughout the country, especially in Colorado and northern states bordering Canada. Levels tend to fluctuate based on weather and ventilation, so great variances can exist between regions, structures, or even rooms within the same building. Since radon comes up from the ground, higher amounts are often found in basements and on the first floor of buildings.
How to measure radon levels
As radon levels can vary between rooms, tests should measure as many individual rooms as possible for an accurate reading. Standard procedures take 48 hours—to save time, multiple spaces may be measured at once with several radon detectors. (One radon detector moved from room to room will also work when time permits.) Emphasis should be placed on measuring radon levels in the basement, ground floor, and rooms occupied by people.
When setting up the radon detector, it is important for the device to remain undisturbed on a flat, stable surface for the duration of the measurement to ensure an accurate reading. While modern devices have sensors to monitor movement, it is also recommended to place warning tape and signs around the detector to reduce the likelihood of tampering.
Windows should be closed during the entire measurement, and devices should be placed at breathing height as far away from fans or sources of ventilation as possible. However, the ventilation system in the building should run as normal. Each radon detector brand is different, so the instruction manual should be thoroughly read before the test is conducted.
Professional radon detectors usually come with reporting options, including mobile variations allowing users to implement an app to extract data from a device via Bluetooth. The data should include details on the room in which the measurement was made, the dates of measurement, the length of measurement, and long-term average radon levels to keep track of fluctuations over time.
Some devices also come with software allowing users to plot radon levels’ movement on a graph during the measurement period. This is important when a school or workplace is using a ventilation system only active during work hours. Often, a measurement will show the radon levels being low when ventilation is switched on, and rising again during the night. Additionally, radon levels change with the seasons, being generally higher in winter when windows are kept shut and indoor heating causes the air to rise. This results in a negative pressure inside the building that pulls more radon out of the ground.
When to mitigate (and how to get buy-in)
EPA recommends taking action when radon levels are measured to be 4 pCi/L or higher during the time the building is used. To truly reduce health concerns, earlier mitigation is recommended. According to the World Health Organization (WHO), the risk of lung cancer increases by 16 percent per 2.7 pCl/L increase in radon exposure. It is also estimated lowering the national average to 2 pCi/L could reduce deaths attributed to radon by 50 percent. In fact, Congress has set a goal for indoor radon levels to be no higher than standard outdoor levels at 0.4 pCi/L.
When determining whether or not it is appropriate to mitigate, it is important to keep in mind radon levels fluctuate throughout the year. It is common to see levels double during the winter compared to the summer—a measurement of 4 pCi/L in January is less worrisome than the same reading in July. When there is doubt, another measurement can be done a few months after the first test to compare.
As radon is an often-underestimated health concern not uniformly regulated across the country, obtaining buy-in is often required for its mitigation. Sharing information and having the discussion early on can help reduce conflict down the road—one good solution is to create a signed document stating at what level radon will be mitigated.
Buy-in works best when it comes from the senior level. EPA recommends targeting administrators and building managers, connecting them with a radon professional for additional information. Becoming or working with an American Association of Radon Scientists and Technologists National Radon Proficiency Program (AARST-NRPP)-certified radon professional also helps build credibility. Additionally, linking the effort to general health initiatives or departments already focusing on health builds further trust. For schools, obtaining support from parents is also effective.
Mitigating radon in nonresidential buildings is similar to procedures for homes. To begin, it is recommended to walk the grounds to get a feel for where there might be structural or mechanical issues allowing higher radon concentrations to enter the building. Expansion joints, foundation cracks, sub-slab HVAC ducts, and building pressurization patterns should be checked. A positive pressure area tends to keep radon out, whereas a negative pressure area can allow its presence.
If mitigation is necessary, it should start in the areas with the highest radon levels first to potentially reduce the presence in nearby rooms as well. Radon solutions vary depending on where the gas is coming from and the size of the leak. Solutions could include installing polyvinyl chloride (PVC) piping with fans from the sub-slab, changing the settings of HVAC systems, or closing cracks in the foundation. Retesting should be conducted at regular intervals after mitigation to ensure the solution was effective.
Prevention is the best cure
Just as in health, prevention is the best cure with radon exposure. Considering ways to stop the gas from the beginning of building construction is the best approach to ensure safe IAQ. This can be done in many ways. Creating a radon-blocking membrane in the foundation, as is required in Norway, is one solution. Another is being sufficiently meticulous to ensure there are zero cracks in the foundation, along with properly sealing any gaps or potential entrance-points.
Additionally, setting up the ventilation system to create a mild positive pressure indoors makes it more difficult for radon to enter the building. The ability for users of the building on the ground floor to have operable windows will also allow for more natural ventilation to help keep radon levels at a minimum.
Oyvind Birkenes is the CEO of Airthings (formerly called Corentium), a Norway-based company involved in air quality solutions. He has more than 20 years of technology industry experience, including key roles at Texas Instruments and Chipcon.