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Radionuclides in Air

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This page describes the radionuclides commonly found in air.

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Some radioactive materials - most of which are naturally occurring elements - are actually air pollutants. All of them, as a whole, are a relatively small proportion of the many elements and chemicals that are considered air pollution. Radon is the most significant of these elements, but most radon exposure stems from the indoor environment. Improving technology continues to minimize man-made radioactive air pollutants and monitor air quality.

Under EPA’s Clean Air Act, significant air pollutants include ozone, particulate matter, nitrogen dioxide, sulfur dioxide and lead. An additional 189 air pollutants are considered toxic in small amounts, including cadmium, benzene and radionuclides.

Air pollution affects everyone to some extent, but it is particularly harmful to the following groups:

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Terrestrial Radiation (Radon)

The majority of our total radiation exposure stems from naturally-occurring radioactive materials, including uranium, thorium and radon. The most significant of these is radon — a colorless, tasteless, and odorless gas that comes from the decay of radium found in nearly all soils. Levels of radon vary throughout the country.

From the ground, radon migrates into homes and other buildings through cracks and holes in foundations or walls. Accumulated radon, trapped inside the buildings, may become a health hazard if the building is not properly ventilated. Radon in the air decays into radioactive polonium, which, if inhaled, can damage lung cells and can even lead to lung cancer.

In a January 2005 news release, the U.S. Surgeon General Richard H. Carmona noted that radon is the second leading cause of lung cancer in the United States, with more than 20,000 Americans dying each year from radon-related lung cancer. Only smoking causes more lung cancer deaths, and smokers exposed to radon are at an even higher risk than nonsmokers. Dr. Carmona also noted that “radon can be detected with a simple test and fixed through well-established venting techniques.”

Radon can be detected with a simple test and fixed through well-established venting techniques.

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Cosmic Radiation

Another 8% of our radiation exposure comes from outer space, originating from our galaxy, other galaxies, and even our own sun. People in higher elevations, such as those who live in the mountains or fly on airplanes, experience higher doses of cosmic radiation. The atmosphere shields us from cosmic radiation. The more air that is between us and outer space, the more shielding that we have. While radon is absorbed through breathing, cosmic particles are absorbed through the skin.

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Industrial Emissions

Nuclear power plants, mining facilities, and research facilities are man-made contributors to radioactive air pollutants. These industrial facilities account for less than 0.1% of the average American's total radiation exposure, much less than that from medical x-rays and various consumer products.

Health and the environment become a concern when radionuclides are released into the air as a result of facility accidents, nuclear weapons testing or acts of terrorism. Air monitors are used to track changes in radiation levels and assess the spread of contamination in the case of a radiation accident or incident.

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Who is protecting you

U.S. Environmental Protection Agency (EPA)

Under EPA’s Clean Air Act, EPA’s Office of Air and Radiation (OAR) develops national programs, technical policies, and regulations for controlling air pollution and radiation exposure. Within OAR, the Office of Radiation and Indoor Air (ORIA) maintains responsibility to protect the public from the risks of radiation. Additionally, EPA’s RadNet program monitors the air throughout the country for changes in radiation levels and assesses the spread of contamination in the case of a radiation accident or incident.

U.S. Department of Energy (DOE)

DOE’s Office of Environmental Management issues regulations related to spills, releases, and clean-up of radiation in the air from DOE facilities. DOE has requirements that limit how much radiation may be released from its facilities, and it ensures that all facility operators comply with these internal agency standards.

U.S. Nuclear Regulatory Commission (NRC) and Agreement States

The primary mission of NRC is to protect public health and the environment from the effects of radiation from nuclear reactors, materials, and waste facilities. Thirty-four states have signed formal agreements with NRC, providing the states regulatory responsibility over small quantities of special nuclear material, special nuclear material sources and their byproducts. These states are known as Agreement States.

The States

Individual states have the authority to also establish standards for radiation protection, and many have adopted such standards. The state agencies also are empowered to enforce compliance with these standards in order to ensure public health and the environment are protected from industrial and governmental uses of radioactive materials.

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What you can do to protect yourself

Test Your Home for Radon

Testing is the only way to know if you and your family are at risk from radon. If you do not wish to hire a professional, using a low-cost, “do-it-yourself” radon test kit only takes a few minutes of your time. You should test your home for radon every two years, and retest any time you move, make structural changes to your home, or occupy a previously unused level of a building. Radon in the air is measured in units known as "pico curies per liter," or "pCi/L." Sometimes test results are expressed in Working Levels (WL) rather than pCi/L. If you have a radon level of 4 pCi/L (0.16 WL) or more, take steps to remedy the problem as soon as possible. If you find radon concentrations above 4 pCi/L, you can reduce them through methods that can be as simple as sealing cracks in floors and walls or as complex as installing systems that use pipes and fans to draw radon out of the home or building.

Be Informed

Cosmic radiation is a natural part of the background radiation, and there is little that can or needs to be done to protect yourself from it. Emissions of radioactive materials from routine operations of nuclear power plants should not require any protective actions on your part. However, in the event of an accident or a significant unplanned release, you may be instructed to evacuate or shelter-in-place. During such an event you should listen to the radio or television for information and instructions from your local emergency management directors and/or your elected officials.

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March 28, 2012. U.S. Environmental Protection Agency
This website provides information about radon and EPA’s radon protection activities.
Air Quality Planning & Standards
March 28, 2012. U.S. Environmental Protection Agency
On this page, you will find general air quality links. It include links for information on the Clean Air Act, air emissions and visibility.
March 29, 2012. U.S. Environmental Protection Agency
On this website, you can learn about RadNet. It is EPA’s national network of radiation monitoring stations. RadNet regularly collects air, precipitation, drinking water and milk samples to test for radioactivity.
Guidance on Implementing the Radionuclide NESHAPS (PDF) (94pp, 979Kb[about pdf format] )
U.S. Environmental Protection Agency, Office of Radiation Programs
This document contains a brief history of radiation protection in air. Its main purpose is to guide EPA’s regional offices as they put the National Emission Standards for Hazardous Air Pollutants into effect.
Radiation: Facts, Risks and Realities (PDF) (14pp, 1.17Mb[about pdf format])
April, 2012. U.S. Environmental Protection Agency
This document provides facts about ionizing radiation. It also discusses risks and benefits of using ionizing radiation.
March 26, 2012. U.S. Environmental Protection Agency
On this page, you can read a description of EPA’s National Emissions Standards for Hazardous Air Pollutants (NESHAP), Radionuclides. The page also provides links to more detailed information about NESHAPS.
Directory of Agreement State and Non-Agreement State Directors and State Liaison Officers
March 28, 2012. U.S. Nuclear Regulatory Commission
This site provides a list of Nuclear Regulatory Commission Agreement and Non-Agreement State contacts.
Sources of Radiation
March 28, 2012. U.S. Nuclear Regulatory Commission
On this page, you can see a chart of the public’s exposure to ionizing radiation. It shows natural and man-made sources.

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