Radon as a health hazard
Radon is a naturally occurring radioactive gas produced through the decay of radium found in rocks and soils. While it contributes significantly to the background radioactivity in the environment, radon can become a health hazard when it accumulates in enclosed spaces like homes and buildings, particularly in areas with high uranium concentrations in the soil. Indoor radon levels are often much higher than outdoor levels due to air dilution, leading to potential health risks. The primary concern comes from radon-222, which has a half-life of 3.8 days and decays into radioactive particles that can be inhaled. These particles can attach to dust and become trapped in the lungs, potentially damaging sensitive lung tissue and increasing the risk of lung cancer. The U.S. Environmental Protection Agency (EPA) estimates that radon products contribute to over 20,000 lung cancer deaths annually. To mitigate these risks, the EPA recommends remediation strategies when radon levels exceed 4 picocuries per liter of air, often involving proper ventilation in homes. Understanding radon’s health implications is crucial for homeowners, especially in regions known for higher soil radium concentrations.
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Radon as a health hazard
DEFINITION: Radioactive gas that occurs naturally in rocks as the decay product of radium
Although it accounts for approximately 50 percent of the normal background radioactivity in the environment, radon can pose a health hazard if it accumulates in houses and other buildings.
Unsafe levels of have been detected in structures built over soils and rock formations containing uranium. One of the radioactive products of uranium is radium, which decays directly to radon. Every 3 square kilometers (1.2 square miles) of soil to a depth of 15 centimeters (6 inches) contains about 1 gram (0.035 ounces) of radon-emitting radium. Certain regions across the United States and around the world contain comparatively high concentrations of radium in their rocks and soils. One such area is the Reading Prong, which stretches from southeastern Pennsylvania to northern New Jersey and portions of New York.
Three forms of radon are generated in the decay of uranium in rocks and soils. The potential health risks are posed by the radon with an atomic mass of 222 (radon 222), which has a 3.8-day half-life. Radon 220 and radon 219 also form in rocks and soils, but these isotopes have half-lives of 56 seconds and 4 seconds, respectively. The shorter half-lives of these isotopes compared to radon 222 give them a much greater chance to decay within rocks and soils before they can become airborne; thus they are of lesser radiological significance.
Radon is chemically inert, and within its 3.8-day half-life, the gas can become airborne and enter buildings through small fissures in the foundations. Indoor radon levels are typically four or five times more concentrated than outdoor levels, because air dilution occurs in outdoor settings. Contributions to indoor radon levels also come from building materials, well water, and natural gas.
Airborne radon itself poses little hazard to health. As an inert gas, inhaled radon is not retained in significant quantities by the body. The potential health arises when radon in the air decays, producing nongaseous radioactive products. These products can attach themselves to dust particles or aerosols. When inhaled, these particles can be trapped in the respiratory system, causing of sensitive lung tissue. Sustained may result in lung cancer. The US Environmental Protection Agency (EPA) has estimated that more than twenty thousand deaths from lung cancer each year are attributable to radon products. The EPA recommends measures if radon levels in a building exceed 4 picocuries per liter of air. Remediation techniques to relieve indoor radon usually involve ventilating basements and foundation spaces to outside air.
Bibliography
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"Radon." World Health Organization, 25 Jan. 2023, www.who.int/news-room/fact-sheets/detail/radon-and-health. Accessed 22 July 2024.