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What is radon, exactly?

Radon is a colorless, odorless, tasteless gas caused by the natural breakdown of uranium in the soil under your home. This hazardous gas seeps into homes from the surrounding soil through porous cement, sump pumps, cracks in the foundation, crawl spaces, etc. Your home acts like a vacuum, drawing radon in.

When inhaled, radon gives off radioactive particles that can damage the cells that line the lung. Radon is the second leading cause of lung cancer and the number one cause of lung cancer in non-smokers. Radon kills 22,000 people every year in the U.S.


Where is it found?

Radon is present in every home. According to the United States Environmental Protection Agency (USEPA), approximately 30-40% of the homes tested nationwide have elevated levels of radon that need to be corrected. Any home can have a radon problem: old homes, new homes, well-sealed and drafty homes, and homes without basements. In fact, you and your family are most likely to get your greatest radiation exposure at home. That is where you spend most of your time.

Your level of risk depends on the level of radon in your home and the length of time you are exposed. To ensure that your home is safe, do what millions of Americans have already done…have your home tested. 


Are there areas (towns or counties) in Maine where radon is more prevalent?

Radon can be found all over the U.S. However, the rocks and soils of Maine create more radon than most other States. High levels are found in all types of buildings, including many schools, offices, and homes. Approximately one in three Maine homes has air radon concentrations over four (4) picocuries per liter of air (pCi/L). While radon problems may be more common in some areas, any home may have a problem.


Where does radon come from?

The soil. Radon is produced from the natural decay of uranium that is found in nearly all soils. Uranium breaks down to radium. As radium disintegrates, it turns into a radioactive gas…radon. As a gas, radon moves up through the soil and into the air you breathe.


Where is your greatest exposure to radon?

While radon is present everywhere, and there is no known safe level, your greatest exposure is where it can concentrate – indoors, where you spend most of your time – at home. Your home can have radon, whether old or new, well-sealed or drafty and without a basement.


How does radon enter a home?

Since radon is produced from soil, it is present nearly everywhere. Because soil is porous, radon gas can move up through the dirt and rocks and into the air we breathe. If allowed to accumulate, radon becomes a health concern.

Radon can enter your home via several entry points or pathways:

Cracks in concrete slabs
Spaces behind brick veneer walls that rest on uncapped hollow-block foundations
Pores and cracks in concrete blocks
Floor-wall joints
Exposed soil, as in a sump or crawl space
Weeping (drain) tile, if drained to an open sump
Loose-fitting pipe penetrations
Building materials: brick, concrete, rock
Well water

In general, whenever air enters a home from the underlying soil, some radon will likely come with it.

What happens after radon gets Into the home?

Radon levels are often highest at the entry point – typically in the lower part of a building. As radon gas moves upward, diffusion, natural air movements, and mechanical equipment (such as a forced-air ventilation system) distribute the radon through the home. Radon gas becomes more diluted in the home's upper levels because there is more fresh air for it to mix with.

Greater dilution and less house vacuum effect occur when the house is more open to the outdoors, as during the non-heating season. This generally results in lower indoor radon levels in the summer compared to the winter.

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