Radon in Minnesota Homes

January is National Radon Action Month - Watch this video to see how radon has impacted one Minnesota family.

 

The Minnesota Department of Health (MDH) provides information on radon and how to protect your family's health. MDH also recommends that every Minnesota home be tested for radon.

Click to download Radon Brochure

What is radon?

Radon is a colorless, odorless radioactive gas that seeps up from the earth. When inhaled, it gives off radioactive particles that can damage the cells that line the lung.

Long term exposure to radon can lead to lung cancer. In fact, over 21,000 lung cancer deaths in the US each year are from radon, making it a serious health concern for all Minnesotans.

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Where does radon come from?

Radon comes 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 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. And where you spend most time-at home. Your home can have radon whether it be old or new, well-sealed or drafty, and with or without a basement.

Why is radon a common problem in Minnesota Homes?

High radon exist in every state in the US. In Minnesota, one in three homes (1/3) has radon levels that pose a significant health risk. Some factors that further contribute to Minnesota's high radon levels include:

  • Minnesota's geology produces an ongoing supply of radon.
  • Minnesota's climate affects how our homes are built and operate.

How does radon enter a home?

Radon, because it is a gas, is able to move though spaces in the soil or fill material around a home's foundation. Minnesota homes tend to operate under a negative pressure - this is especially true in the lowest portions of the home and during the heating season. This negative pressure acts as a vacuum (suction) that pulls soil gases, including radon, into the lower level of the structure. Some causes of home vacuum are:

  • Heated air rising inside the home (stack effect).
  • Wind blowing past a home (downwind draft effect).
  • Air used by fireplaces, wood stoves, and furnaces (vacuum effect).
  • Air vented to the outside by clothes dryers and exhaust fans in bathrooms, kitchens, or attics (vacuum effect).

Radon can enter a home through the floor and walls -- anywhere there is an opening between the home and the soil. Examples of such openings include dirt floor crawl spaces, unsealed sumps, cracks in slab-on-grade floors, utility penetrations, and the tiny pore spaces in concrete block walls. A basement, of course, provides a large surface area that contacts soil material.

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Major Radon Entry Routes

diagram of major radon entry points
  1. Cracks in concrete slabs.
  2. Spaces behind brick veneer walls that rest on uncapped hollow-block foundations.
  3. Pores and cracks in concrete blocks.
  4. Floor-wall joints.
  5. Exposed soil, as in a sump or crawl space.
  6. Weeping (drain) tile, if drained to an open sump.
  7. Mortar joints.
  8. Loose fitting pipe penetrations.
  9. Open tops of block walls.
  10. Building materials, such as brick, concrete, rock.
  11. Well water (not commonly a major source in Minnesota homes).

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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 forced-air ventilation system) distribute the radon through the home. Radon gas becomes more diluted in the upper levels of the home 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.

Understanding how radon moves through the home environment helps to explain why timing and location are important factors to consider when conducting a radon test.

How can I find out if my home has a radon problem?

MDH recommends that all Minnesota homeowners test their homes for radon. A radon test is the only way to find out how much radon is in your home and if you and your family are at risk. Performing a radon test on your own is easy, inexpensive and takes only a few minutes of your time. The results of a properly performed radon test will help determine if you need to take further action to protect yourself from the health risks of radon.

How can I protect my family from radon?

A number of steps can be taken to lower the amount of radon in a home. A quality radon reduction (mitigation) system is often able to reduce the annual average radon level to below 2 pCi/L. Experienced radon mitigation professionals are available and can install appropriate control systems.

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Updated Thursday, 19-Jan-2012 10:54:14 CST