What is Radon?
Radon is a colorless, odorless, tasteless, and chemically inert radioactive gas. It is formed by the natural radioactive decay of uranium in rock, soil, and water. Naturally existing, low levels of uranium occur widely in earth’s crust. It can be found in all 50 states. Unless you test for it, there is no way of telling how much is present.
When radon undergoes radioactive decay, it emits ionizing radiation in the form of alpha particles. It also produces short-lived decay products, often called progeny or daughters, some of which are also radioactive. Unlike radon, the progeny are not gases and can easily attach to dust and other particles. Those particles can be transported by air and can also be breathed. The decay of progeny continues until stable, non-radioactive progeny are formed. At each step in the decay process, radiation is released.
Sometimes, the term radon is used in a broad sense, referring to radon and its radioactive progeny all at once. When testing measures radiation from the progeny, rather than radon itself, the measurements are usually expressed in working level (WL) units. When radiation from radon is measured directly, the amount is usually expressed in picocuries per liter of air (pCi/L). Nearly one out of every 15 homes has a radon level EPA considers to be elevated—4 pCi/L or greater. The U.S. average radon-in-air level in single family homes is 1.3 pCi/L.
How is radon a health hazard?
Radon is the second leading cause of lung cancer in the United States. Breathing radon does not cause any short-term health effects such as shortness of breath, coughing, headaches, or fever. Research suggests that swallowing water with high radon levels may pose risks, too, although risks from drinking water containing radon are much lower than those from breathing air containing radon.
Radon enters the building through cracks in the foundation, floors and walls, cavities within walls, joints in construction materials, crawl spaces, gaps in suspension floors, and gaps around utility penetrations. Trace amounts of uranium are sometimes incorporated into materials used in construction. These include, but are not limited to concrete, brick, granite, and drywall. Though these materials have the potential to produce radon, they are rarely the main cause of an elevated radon level in a building. The primary routes of potential human exposure to radon are inhalation and ingestion. Radon in the ground, groundwater, or building materials enters working and living spaces and disintegrates into its decay products. Although high concentrations of radon in groundwater may contribute to radon exposure through ingestion, the inhalation of radon released from water is usually more important. Ground water has a higher concentration than surface waters.
The health hazard from radon does not come primarily from radon itself, but rather from the radioactive products formed in the decay of radon. The general effects of radon to the human body are caused by its radioactivity and consequent risk of radiation-induced cancer. Lung cancer is the primary observed consequence of high concentration radon exposures; both human and animal studies indicate that the lung and respiratory system are the primary targets of radon daughter-induced toxicity. More studies are needed to determine the causative relationship to other cancers.
What can I do?
Testing is easily done over a short period of days. Weather can affect the results. Multiple tests may be required.