​Factors Influencing Radon Exposure

The three main factors that affect radon exposure, are geography, where you spend your time indoors, and home air circulation.

1. Geography

Geographically, mountainous regions, the Midwest, and the northern United States (U.S.) have a higher potential for radon.

2. Time Spent Indoors

Because you typically spend most of your time at home and radon tends to accumulate in buildings, this is where you are likely to have the most exposure. Where you spend your time indoors is important because locations nearer to where the radon enters a building (e.g., basements) are likely to have higher concentrations.

Air Circulation

Controlling the air flow in your home with good ventilation or by preventing radon from entering your home will reduce your exposure.​

Health Risks Associated with Radon Exposure

According to the EPA, radon is the number onecause of lung cancer among people who do not smoke, and it is the second leading cause of cancer for people who do. The EPA states that your health risk from radon exposure at home depends “mostly on how much radon is in your home, the amount of time you spend in your home, and whether you are a smoker or have ever smoked."¹ If you smoke and you breathe air containing radon, your risk of lung cancer can increase even more.

The amount of radon in the air is typically measured in picocuries per liter (pCi/L). In the U.S., the average indoorradon level is about 1.3 pCi/L, and the average outdoor level is about 0.4 pCi/L.
 
In the U.S., the EPA estimates the risk of lung cancer from a lifetime (75 years) of exposure to 4 pCi/L of radon as follows:

• For people who have never smoked: About 7 out of 1,000 people could get lung cancer. 
  
• For people who smoke: About 62 out of 1,000 people could get lung cancer. 
  
  It's noteworthy that if you've quit smoking, your risk level is likely to fall within the values determined by the EPA. 

Mana​ging Your Radon Risk

Reducing your risk of lung cancer due to radon exposure involves proactive measures that you can easily incorporate into your lifestyle.

1.    Quit Smoking–Quitting smoking significantly reduces your risk of lung cancer associated with radon exposure.

2.    Test Your Residence–Consider testing your residence for radon, especially if you reside in an area with a high radon potential. 

Act on High Radon Levels–If your radon levels are at or above4 pCi/L, the EPA recommends immediate action to reduce radon in your building. Additionally, if levels fall between 2 and 4 pCi/L the EPA urges people to take mitigation measures.

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Mitigation Timeframes

Mitigation timeframes, as outlined in Public Works Technical Bulletin 200-1-144, offer guidance based on EPA action levels. Generally, the higher the radon level, the more urgent the EPA suggests acting.

For Department of Defense (DoD) housing, the DoD has adopted the EPA guidelines for remediation of radon in living quarters. Contact your housing office for more information on local radon testing and remediation efforts.

More on Radon

​​EPA​​​​
CDC

​EPA Map of Radon Zones​
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