Problem: Radon gas is present in amounts large enough to cause potential health problems.
Background: Radon is a colorless, odorless, tasteless radioactive gas that is present naturally in the environment. Radon is produced from the radioactive decay of uranium. Very small amounts of uranium and radium are present in almost all rocks and soil, so radon is constantly being produced almost everywhere. Exposure to radon and its decay products can cause lung cancer; the greater the amount and the longer the exposure, the greater the risk. For information on other indoor air pollutants.
What to do: Like all gases, radon moves from high to low pressure by airflow, and from high to low concentrations by diffusion, or mixing. If a building provides an easier route, radon gas may enter, become trapped, and eventually decay. (Underground water and some building materials can also emit radon.) Radon can enter a home through sewer pipes, sump pump openings, cracks in the basement floor and walls, and private wells. A drop in air pressure inside a house can help pull the radon indoors from the surrounding soil. This pressure drop can be created by some mechanical systems, furnace operation, or the use of combustion devices.
Most efforts to reduce radon risks in homes center on reducing the entry of radon gas. (Air-cleaning devices may actually increase the problem.) You can buy relatively in expensive canister or alpha-track detectors to test for radon in homes. The canisters with activated char coal are exposed for 48 hours in a closed home and sent to a lab. Alpha-track detectors have a plastic disc which is struck by alpha particles given off by radon decay. The disc, exposed in the home for a period of up to a year, is then read by a lab.
Special advice: High radon levels vary by area within the United States. Alpha-track detectors, which measure long-term averages, are of more value because health risk is related to long-term exposure. When using charcoal canisters, follow directions and keep away from areas of high temperature, humidity, or drafts.
Helpful hint: Professionals in your area also may have more expensive direct-reading instruments to detect radon in your home. They may be set for average results, or to “sniff’ out sources of radon.