Radon (Rn) is a naturally occurring element that develops from the radioactive decay of radium. Health authorities consider it a health hazard because of its radioactivity.
The United States Environmental Protection Agency (EPA) classes radon as a carcinogen, meaning that radon poisoning can lead to cancer. It is the leading cause of lung cancer in non-smokers and the second leading cause in smokers.
Radon is a health risk, as it is not detectable and does not cause noticeable symptoms until its transformation into lung cancer.
In this article, we will examine what radon poisoning is, its symptoms, how to test for the effects of radon, and how to minimize exposure.
Radon is a gas that occurs as the end product of radium decay. Radon poisoning occurs when large amounts enter the body and cause harmful physical changes.
It is a naturally occurring element that takes a gaseous form at standard temperatures and pressures and is one of the densest substances to remain a gas under normal circumstances.
As a colorless, odorless, tasteless gas, radon is undetectable by human senses. Radon poisoning does not cause the same harmful, obvious symptoms as other radioactive substances. Instead, radon exposure can lead to the development of lung cancer.
Radon occurs throughout most environments in very small quantities. However, it can amass in buildings. Radon accounts for the majority of most people's exposure to ionizing radiation.
Radon poisoning is symptomless, meaning that it gives no meaningful indication of exposure.
A person cannot smell, taste, or see radon with the naked eye. It also does not produce any effects in the body until causing the cellular changes that might lead to lung cancer.
For this reason, taking all necessary precautions against radon exposure is extremely important, especially for people who live in a Zone 1 area. This is an area containing higher levels than the EPA deems safe.
A person starting to cough up blood, feel chest pain, or experience breathing difficulties should visit a doctor immediately to rule out lung cancer.
In the early 20th century, quack doctors touted radon as being beneficial to health. People could pay small sums of money to spend time in a "radiotorium" and receive bombardments of radon.
Other companies attempted to add radon to water, but the short half-life of radon meant that it had disappeared by the time the water reached people.
Researchers only discovered its negative health implications at a later date.
In the 1940s and 1950s, companies who set up mines did not widely implement ventilation systems. Doctors attributed lung cancer in miners in the Czech Republic, South Australia, and Southwestern U.S. to radon inhalation. Despite the eventual realization of the hazards, radon-induced lung cancer in miners remained a significant hazard until the 1970s.
Healthcare professionals now acknowledge that inhaling large quantities of radon causes lung cancer. According to the EPA, radon is the second most common cause of lung cancer, after smoking.
Radon causes 21,000 lung cancer deaths per year in the U.S. About 2,900 of those deaths occur in people who have never smoked.
No test is currently available that can diagnose or identify prior exposure to radon.
With the lack of available testing and noticeable symptoms, it is doubly important to minimize exposure to radon.
A range of natural sources give off radon, including:
- uranium ores
- phosphate rock
- igneous and metamorphic rocks, such as granite
More common rocks, such as limestone, also emanate radon, also this is a less common occurrence and levels are lower than other sources.
Natural rock is not the only source of radon. Man-made structures can also be responsible for radon poisoning.
Radon tends to enter buildings at their lowest point. It often makes its way in through splits in foundations, cracks in walls, gaps around pipes, cavities inside walls and the water supply. The gas is likely to build up in poorly ventilated, airtight buildings.
Levels vary a great deal between locations and, although the half-life of radon is less than 4 days, it can build up in high concentrations, especially in areas of low elevation, such as basements or mine shafts.
Two adjacent homes and even two adjacent rooms can vary significantly in their levels of radon. This helpful resource from the EPA shows the areas of the U.S. with the highest natural levels.
Iowa has the highest percentage of homes scoring above a safe radon level, with 71.6 percent of homes potentially at risk. The high levels of radon in Iowa are the result of ancient glaciers that ground down granite rocks over time and deposited them in the form of soil.
Some spring water and hot springs also contain radon.
The exact risks of radon in the home are difficult to assess. Most studies of the risks used data from miners, who will have had far more exposure to radon than is likely in any building.
The biggest cause of lung cancer is smoking, and this can confuse the identification of radon. Non-smokers may have had exposure to second-hand smoke.
A combination of radon and cigarette smoke could potentially be more harmful than exposure to either in isolation.
Some researchers believe that the risk of cancer from radon without exposure to cigarette smoke is so small as to be almost insignificant.
Others, however, believe the risks that radon presents to lung health are understated and deserve more attention.
Some estimate that 1 in 15 homes in the U.S. has elevated levels of radon. Radon test kits are widely available and generally cheap or even free.
There is a selection of radon testing kits available for purchase online.
Radon kits include a collector. A person with the kit should leave it in the lowest habited room of the house for 2–7 days. They can then send the collected sample to a laboratory for evaluation.
If the radon readings are high, a number of methods can help manage the issue.
The most common methods include:
- Sub-slab depressurization, or soil suction: This consists of a vent pipe system and a fan that pulls radon from under the house, venting it to the outside.
- Improving ventilation: Also, avoid moving radon from lower floors to the rest of the home.
- Radon sump system: A sump is an under-floor cavity into which a pipe is inserted. A fan pulls air and radon up and away from the home.
- Positive pressurization: These systems constantly blow fresh filtered air into the home to clear out radon.
Simply making the home airtight does not limit radon levels until implementing other measures.
Although studies have demonstrated the link between radon and cancer, its implications for health at the levels that occur in the home are still up for debate, with smoking making conclusions difficult to reach.
However, all homeowners can put in place adaptive measures if necessary.