Who is Susceptible and How to Stay Safe
Radon is a naturally occurring radioactive gas, which means everyone is exposed to it in some way. However, radon becomes dangerous when it is concentrated, especially in a home or workplace.
After tobacco smoke, radon exposure is the leading cause of lung cancer, according to the Centers for Disease Control and Prevention (CDC). Those who smoke and are exposed to high levels of radon are 10 to 20 times more at risk for developing lung cancer than nonsmokers, as are children who are exposed to both high-level radon and tobacco smoke.
The Environmental Protection Agency (EPA) sets the maximum safe level of radon exposure in the home at 4 picocuries per liter (4 pCi/L), and it is estimated that approximately 6 million homes in the United States have radon levels above the remediation level the EPA recommends.
Despite these clear risks, the general public tends to underestimate the dangers of radon exposure. There is also a great deal of misinformation about radon. For example, it is true that basements and crawl spaces tend to have the highest concentrations of radon. But it is also true that radon can travel, especially through heating and air conditioning systems.
Poor ventilation, moisture control techniques sometimes used in new construction and even certain building materials can increase the risks of radon exposure. The only way to know the level of radon in your home is to test for it. Here is what you need to know about this silent killer.
What is radon, and what does it do?
A highly radioactive, naturally occurring gas, radon was discovered in 1899 by English physicist Ernest Rutherford. German physicist Friedrich Ernst Dorn further refined the discovery in 1900. Chemically inert (non-reactive), radon is odorless and colorless. It comes from the breakdown of uranium or other radioactive elements. Radon is generally found outdoors in rocks and soils, where it rapidly disperses and rarely poses any health concerns.
In comparison with outdoor areas, humans in confined underground locations, especially mines, are exposed to high concentrations of uranium decay from the surrounding natural rock and soil. Radon can build up in underground places such as caves, tunnels and public baths, though typically not to the levels seen in mines.
While most people don’t work underground, the problem for the average homeowner is that radon can easily enter buildings through cracks, holes and construction joints, becoming trapped and unable to disperse. Over time, radon levels in homes, schools or workplaces can build up to unsafe levels. As the radon continues to decay, it forms decay products that can attach to dust and other particles in the air, making it even easier to inhale.
Some areas of the country have higher levels of naturally occurring radon than others. Even if you live in a lower risk area, though, you could still have elevated radon levels in your home. Radon levels can vary widely even among homes in the same neighborhood, regardless of whether they were built by the same company at the same time. Lack of ventilation is a known risk factor for indoor radon exposure, yet even very drafty houses sometimes have high levels of radon.
Radon is carcinogenic, which means long-term exposure to elevated levels can cause lung cancer. Radon is the second leading cause of lung cancer in the United States (and the number one cause among non-smokers), causing an estimated 21,000 deaths per year.
Who is at risk?
Children have an elevated risk of developing lung cancer or other problems related to radon. Their lung shape and size differ significantly from those of adults, and they tend to breathe faster. When exposed to exactly the same amount of radon, the risk for lung cancer is nearly twice as high for children as for adults. In children who are also exposed to cigarette smoke, the risk for lung cancer is at least 20 times greater.
People who work underground, such as in mines, are also at increased risk for exposure, as are those who work in uranium processing factories. However, this risk has been mitigated in recent years by environmental and workplace regulations. Employers in known high-risk fields such as mining must now take active steps to reduce radon levels.
Once exposed to radon, men are more likely than women to develop long-term effects including cancer. Those with chronic respiratory or lung conditions, such as asthma, are also at higher risk for negative effects, and smokers have the highest risk of all adults.
Overall, anyone who lives or works in a building with elevated levels of radon is at risk. Those who live in areas with higher natural concentrations of radon, such as the Upper Midwest, are particularly at risk for exposure. However, radon problems have been found in every state, so don’t assume your home is safe based solely on where you live. In fact, nationwide, nearly 1 in every 15 homes is estimated to have elevated levels of radon. And all types of houses are at risk for having radon problems — old homes, new homes, and homes with or without basements.
Does your home have radon?
Radon often enters homes through the stack effect. Warm air rises and escapes through the upper floors and attic of your home, creating a vacuum in the lower levels that pulls trapped radon gas up from the home’s foundation. The stack effect is most pronounced during the winter months.
Regardless of where you live or what the radon level is in your neighbor’s house, testing is the only way to find out the radon level in your own home. The EPA recommends testing all homes that are located below the third floor of a building, even if yours was built with new radon resistant building methods. Fortunately, even high levels of radon can be mitigated.
According to the EPA, do-it-yourself tests are just fine if you’re not planning to sell your home soon. You can find these tests online, as well as in some hardware or big box stores. Start with a short-term test kit, which will stay in your home for 2 days to 90 days, depending on the exact type of device you choose.
Place the kit at least 20 inches above the floor in a commonly used room on the lowest level of your home, but not in the kitchen or bathroom. Keep all windows and doors shut as much as possible, and turn off fans that bring in outside air. It’s fine to use exhaust fans briefly and to run the heater and air conditioner as usual. Don’t do a 2- or 3-day test during strong storms or high wind conditions, as these can affect the results. When the test is complete, reseal the kit and send it to the specified lab for analysis. You will get results within a few weeks.
If your short-term test shows a radon level of 4 pCi/L or higher, test again. If you need results quickly, or if your first test shows a level of 8 pCi/L or above, do another short-term test and average the two results. Otherwise, consider a long-term test, which does a better job of helping you understand your home’s average radon levels over time. Long term tests remain in your home for more than 90 days, but are otherwise very similar to short-term tests.
If a long-term test, or the average of two short-term tests, shows a radon level of at least 4 pCi/L, it is important to have your radon levels remediated right away. If your radon level is between 2 pCi/L and 4 pCi/L, you might want to consider remediation, especially if anyone in your home has respiratory conditions or smokes.
If you plan to sell your home, it may be better to have its radon level professionally tested. Home buyers often prefer the reassurance of knowing an outside third party performed the testing, and they may be interested in radon levels in areas you don’t currently use, such as an unfinished basement. Your state radon office is a good source to find a qualified professional radon tester. Testing typically costs $150 to $800, depending on your geographic location and the specifics of your home.
Note that combustion appliances like your furnace are also possible sources of radon in the home. And your HVAC system can push radon through your home’s ducts. In many cases, homes with basement furnaces have radon levels on the first floor as high as those found in the basement. Getting a new furnace and making sure you have the best possible equipment, as well as ensuring it is regularly maintained by a professional, can help to bring down the radon levels in your home.
If your radon levels are in the questionable range, between 2 pCi/L and 4 pCi/L, this could be enough to bring them down to an acceptable value in the living areas of your home. If your radon levels are higher, you will still need professional remediation, but replacing your furnace can help to minimize future buildup of radon.
How do I get rid of radon?
High levels of radon (above 4 pCi/L) must be professionally mitigated. Your state radon office can help you find a certified radon specialist in your local area. There are a wide range of mitigation options, depending on the type of home you have, but most fall into the general category of active soil depressurization, or ASD. The basic principles of ASD are pulling out the radon gas, safely channeling it, and venting it back outdoors to harmlessly dissipate.
Sub-slab suction, as the name implies, pulls radon gas from the soil beneath your home’s foundation. In drain tile suction, a pipe is used to tap into the drain tiles around a home. Drain tiles are usually found on homes in areas with a high water table or known drainage issues. Sub-membrane suction may be used in homes with a crawl space below, where the soil is covered with plastic sheeting. A pipe is run through the plastic sheeting to pull out the radon gas.
Regardless of which specific method is used, the gas is then channeled through a pipe that runs straight up to at least 10 feet above the roof and 10 feet away from any windows, doors or openings to your home or adjacent buildings. A radon fan is installed in the attic or on the roof to ensure the radon can’t leak back inside.
Depending on the specifics of your home’s design, construction, size and foundation, as well as the local climate, radon mitigation may cost between $800 and $1,500, with a national average of $1,200. However, your costs could be higher depending on what else is involved in your project, as well as aesthetic concerns about the look of your home.
Basement sealing is an important part of radon mitigation, as it closes entry points for radon gas and reduces the amount of conditioned air that is lost from your home. However, it is not enough on its own. Your house will continue to settle over time, opening new cracks. Therefore, basement sealing should only be used in tandem with other types of radon mitigation.
An air to air heat exchanger, also known as a heat recovery ventilator or HRV, can help keep your home properly ventilated, reducing both radon levels and other airborne pollutants. Again, it is not enough on its own, but it can be used alongside a radon mitigation system to improve results.
Passive mitigation systems, which rely on natural pressure differentials rather than fans, are not as effective as active systems. However, they may be an option for homes with radon levels in the questionable range of 2 pCi/L to 4 pCi/L.
It’s important to re-test your home for radon after your mitigation system is installed to ensure everything is working properly. This test should be performed at least 24 hours, but no more than 30 days, after system installation. Your radon specialist will likely perform their own test, but the EPA notes an independent test will remove any possible conflict of interest. The EPA also suggests testing every two years just to make sure your radon levels are still where they should be.
If your mitigation system doesn’t completely reduce radon to acceptable levels, you might consider adding pressurization to your basement or the lowest level of your home. This can help keep radon out, but it can also raise your monthly energy bills and introduce moisture. Therefore, it is not considered a first line of defense against radon.
Are you ready to test your home for radon?
Radon is a colorless, odorless, naturally occurring gas that is sometimes known as a silent killer. It is the leading cause of lung cancer among nonsmokers, and it dramatically raises cancer risks among smokers. Children are at particular risk from radon, due to their smaller lung size and higher respiration rate.
Fortunately, radon is relatively easy to remove from your home, even if you have a high starting concentration. Test your home with a do-it-yourself kit or have it professionally tested. If your radon levels are high, a radon specialist can install a mitigation system and bring your radon levels down to an acceptable range. With your family’s health on the line, it only makes sense to test for radon as soon as possible.