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Environmental Topics

Radon Data

picture of a family standing in front of a houseRadon is the leading cause of non-smoking related lung cancer in the United States, and smokers living in high radon homes are at greater risk of lung cancer.

Radon has no color, odor or taste, making it difficult to detect without testing.


view data about radon


What is radon?

Radon is a naturally occurring radioactive gas that emanates from soil and bedrock, including granite, and can seep into homes primarily through cracks and seams in foundation floors and walls. It may also enter through well water. Radon is a known carcinogen, a substance capable of causing cancer in living tissue. When radon accumulates in indoor air, it poses an increased risk of developing lung cancer.

As the Granite State, potential exposure to radon in New Hampshire is greater than the national average. In the U.S., the average level of indoor radon is 1.25 picocuries per liter (pCi/L) but here in NH, it is estimated to be 1.8 pCi/L.

How is radon measured?

The concentration of radon in the air is measured in units of picocuries per litre (pCi/L).The US Environmental Protection Agency (EPA) has established 4.0 pCi/L as the level at which action should be taken to reduce radon to under 2.0 pCi/L.

Which communities in NH are at greatest risk?

In general, communities in southeastern and eastern New Hampshire have the highest percentage of homes with elevated radon levels. Rockingham, Carroll and Coos counties have several communities in which more than half of the homes tested had elevated radon.

What health risks are associated with exposure to radon?

Almost all risk from radon comes from breathing air with radon. Exposure to radon gas is the second leading cause of lung cancer in the United States, with more than 21,000 deaths attributed annually to radon-related lung cancer. Radon is associated with approximately 100 lung cancer and related deaths in New Hampshire residents each year.

It is important to realize, there is no safe level of radon. Any exposure poses some risk of cancer. Smokers have an increased chance of developing lung cancer in a home where radon gas is found.

How can I test my home for radon?

There are "do-it-yourself" radon test kits available through the mail, in hardware stores and other retail outlets. If you prefer, you can hire a nationally-certified radon measurement professional.
For information on certified radon contractors, visit:

What data are included about radon in New Hampshire’s Tracking program?

The available data related to radon focus on awareness, testing behavior, test results and mitigation behavior.

view data about radon

Where can I learn more about radon?

Portable Document Format Symbol Portable Document Format (.pdf). Visit nh.gov for a list of free .pdf readers for a variety of operating systems.

New Hampshire Environmental Public
Health Tracking Program
NH Department of Health and Human Services,
Division of Public Health Services
29 Hazen Drive  |  Concord, NH 03301
(603) 271-4988  |  (800) 852-3345 ext.4988