Radon is a radioactive gas that arises from the natural radioactive decay of radium, which is a natural decay product of uranium. Scientifically, “radon” is known to be radon-222, the most abundant isotope of the element radon. The terms radon and radon-222 are often used interchangeably when referring to the indoor radon issue. As a noble gas, radon is colorless, odorless and chemically inert and cannot be detected by human senses. Also, since radon is not chemically reactive with most materials, it will move freely as a gas. Radon has a radiological half-life of 3.8 days, and can move substantial distances from its point of origin. Radon’s primary hazard arises from inhalation of the gas and its highly radioactive heavy metallic decay products (Polonium, Lead, and Bismuth) which tend to collect on dust in the air. The problem arises when these elements stick to the delicate cells lining the passageways leading into the lungs.
Radon Health Risk
Radon is a Class A carcinogen, which means it is known to cause cancer in humans. It is the second leading cause of lung cancer in the United States, resulting in approximately 21,000 lung cancer deaths each year. Only smoking causes more lung cancers.
A Radon Gas reading of 4 pCi/L is equivalent to 200 chest x-rays/yr.
A Radon Gas reading of 10 pCi/L is equivalent to smoking a pack of cigarettes a day
The problem occurs when radon and radon decay products (RDPs) are breathed in. Radon is exhaled, as are many of the RDPs, but some of the RDPs get trapped in the lungs. As they undergo radioactive decay and emit alpha energy, the alpha particles can strike sensitive lung tissue, causing physical and/or chemical damage to the DNA.
When alpha particles strike and damage a lung cell, the cell will either:
- Die (which seems like a bad thing, but new cells are generated to replace dead cells)
- Repair itself and heal
- Try to repair itself, but do so incorrectly. Eventually, this can lead to the formation of cancerous cells.
Not everyone who breathes radon will develop lung cancer. Your risk is determined by such things as:
- How much radon is in your indoor environment.
- The amount of time you spend in that indoor environment.
- Whether you smoke or ever have smoked.
The only known health effect of radon is an increased risk of lung cancer, and exposure to elevated radon levels does not result in any warning symptoms like headaches, nausea, fatigue, or skin rashes. The only way to know whether you are being exposed to elevated radon levels is to test your home (and other indoor environments).
Many national and international organizations believe radon is an important environmental health concern, and they support testing for radon and reducing exposure to elevated radon levels. Just a few of those organizations are listed below.
♦ American Lung Association
♦ American Medical Association
♦ Centers for Disease Control
♦ Environmental Protection Agency
♦ International Commission on Radiological Protection
♦ National Academy of Science
♦ National Council on Radiation Protection and Measurement
♦ U.S. Surgeon General
♦ World Health Organization
Additional risk information is available at several locations online. The U.S. EPA’s Assessment of Risks from Radon in Homes can be found at their website at http://www.epa.gov/iaq/radon/risk_assessment.html
The U.S. Surgeon General issued a National Health Advisory on Radon on January 13, 2005, warning the American public about the risk of breathing radon. The press release can be viewed at http://www.surgeongeneral.gov/pressreleases/sg01132005.html.
The National Research Council’s Commission on Life Sciences has posted The Health Effects of Exposure to Indoor Radon at http://books.nap.edu/books/0309056454/html/. This report, commonly known at the BEIR VI report (the sixth report on the Biological Effects of Ionizing Radiation) was released in February of 1998 by the National Academy of Sciences, and represented the most definitive accumulation of scientific radon risk data available at that time. An Executive Summary and a Public Summary are also available at http://books.nap.edu/html/beir6/.
Another interesting study, Residential Radon and Lung Cancer Case-Control Study, conducted by the University of Iowa School of Public Health, can be found at http://www.cheec.uiowa.edu/misc/radon.html.