You are a non-smoker. But if you think it would give you a fair amount of protection from lung cancer, you are wrong. Smoking is still the top cause of lung cancer. Unfortunately, the number two cause of lung cancer in the US is lurking right there in your home, unseen and unrecognized. It goes by the name of radon.
What is Radon?
Radio is a radioactive gas produced when radium disintegrates further. It is colorless, odorless and causes no palpable discomfort. Radon is about eight times heavier than air at sea level, and it dissolves in water to some extent. The bedrocks and the soil that contain radioactive uranium and thorium emit radon which enters the atmosphere and mixes with the ground water.
How does radon get into our homes?
All the radon entering our homes comes from the outside, except in cases where radon-emitting building materials are used in house construction. Indoor air mostly comes from outdoor atmospheric air that has low radon levels. But soil gas from the ground can be high in radon, especially if the area has uranium-rich rocks underneath.
Normally, less than 1 percent of indoor air comes from soil gas, but in some houses, it can be as high as 20 percent. Low internal air pressure, certain features of the ground, and cracks in foundation, may be to blame. Radon-rich groundwater can also contribute to indoor radon as it gets released when water is used for washing and bathing.
Being extremely heavy, radon tends to remain at higher concentrations in the lower levels of buildings. Typically, the basements, the crawl space under the houses, and the lower floors, have high levels of radon. But if the water supply is high in radon, the upper floors can be just as affected or if not more.
How does radon cause lung cancer?
Radon, like all other radioactive elements, is highly unstable. Just like it originates from radium, which is formed when radioactive Uranium and Thorium present in earth’s crust decay, radon itself keeps decaying into smaller atoms of polonium, lead and bismuth. They are called radon daughters. The radon in your home gets reduced to half its quantity within 3.8 days, the period known as its half-life, all the while radiating high-energy alpha particles. Even though radon decays pretty fast, the radon daughters stick to the dust particles in the air and remain indoors for a longer period.
Exposure to high energy radiation causes irreversible changes in living tissues and may initiate cancer growth. Remember how Marie Curie and her daughter Irene, who experimented with radioactive elements like radium and polonium, succumbed to radiation-related diseases? Radon and its daughters enter our lung along with the air we breathe, and they keep releasing radiation within our lungs. Among the radioactive radon daughters, polonium-210 is the main lung-cancer causing agent.
How can we detect the presence of radon in our homes?
Radon is present in all houses in varying degrees. Testing is the only way to determine if the radon level in your home is within limits; the maximum permissible level stipulated by the Center for Disease Control being 4 picocurie per liter of air. World Health Organization recommends less that 2pCi/L. The truth is that, there is no safe limit of radon; the lower the levels, the lesser the risk.
There are two types of testing available. The short-term test takes 2-3 days. The exposed kit is kept in a frequently used lower level room and then sealed and sent for analysis. It cannot be considered the true indicator of indoor radon levels that vary throughout the year. But it gives quick results, and a second test is done, if the levels are 4pCi/L or more. The long term test is conducted over a period of minimum 3 months; it can even extent up to a year. The result shows the average level since radon concentration can vary seasonally.
Are there any precautions to be taken to avoid excess radon in indoor air?
For existing buildings, sealing the cracks in the foundation and drywalls, and maintaining a slightly higher indoor air pressure compared to the air pressure outside, will prevent the soil gas from entering into the building. If the water supply has high radon content, reducing it at the point of entry will also reduce radon load.
For buildings under construction, installing a radon-resistant passive system can go a long way in reducing radon levels. In case levels are high in future testing, the system can be activated by simply installing a vent fan.
Once high levels of radon are detected in either a long-term test or a second short-term test, mitigation measures need to be initiated immediately. State radon centers can help locate certified mitigation professionals in your area.
Some of the silly reasons that keep people from testing radon levels:
- It can’t be as bad as they say. It’s rather hard to believe that, unlike tobacco smoke, something that cannot be seen, heard, smelled or felt in any way can be so dangerous. American Lung Association, as well as the Centers for Disease Control (CDC), rates radon as the most common environmental risk after tobacco smoke. The exact toll due to radon-related lung cancer cannot be determined, but EPA estimates it to be around 21,000; next only to tobacco-related lung cancer deaths. Extensive studies have been conducted on lung cancer among miners who have been exposed to high levels of radon. Smoking increases the risk tremendously, but both these causes preventable.
- We have lived here for so many years. People living in older houses may feel a false sense of safety because they associate radon problem with new construction materials and methods. Many synthetic materials used in house construction do release potentially dangerous carcinogens like formaldehyde into the indoor air, but the radon in the house mainly comes from soil gas and water. Certain methods of constructions may contribute to radon accumulation in the house, but all houses, both old and new carry the same risk. Testing is the only way to determine it.
- If radon is everywhere, there’s no point in fighting it. Radon is present in air, water soil and rocks, but its concentration varies. The average radon level in the atmosphere is 0.2pCi/L, but in most places in the US, it may be over 200 pCi/L in the soil gas. It has been found that exposure to higher levels significantly increase the risk of lung cancer compared to low level exposure. Equipping underground mines with good ventilation system has helped reduce this occupational hazard in miners. With proper radon mitigation the radon levels in indoor air can be kept below 2pCi/L, lowering lung cancer risk.
- Testing and mitigation are too expensive. Contrary to what many people think, testing is rather easy and non-disruptive. There are many simple do-it-yourself testing kits for radon available for online purchase. Retail outlets near you may carry such kits too. Or one can contact state radon office and avail the service of certified professionals. If the levels are slightly higher than 4 pCi/L, installing a simple venting system with a fan to redirect the air to the outside may solve the problem. Only very high levels require the involvement of radon mitigation experts.
- Our neighbors tested fine. The radon levels in adjacent buildings are no indication of your status. When the levels vary to a great extent between the different floors of the same house, how can the variation between houses predicted?
- Real estate value. Some people are afraid that if high radon levels are detected in their home, the real estate value of the property may go down. The truth is that if you can show certified test results after necessary radon mitigation steps are taken, it may earn the trust of prospective buyers. In fact, some buyers insist on testing by a third party.
Whether you live in an old house or new, radon testing and mitigation should be a priority. If you are constructing a new house, incorporate radon-resistant system in to the structure.