1. What is radon?
Radon is a colorless, odorless radioactive gas that’s produced by decaying uranium. It’s present in nearly all soils, and very low levels of radon are found in the air we breathe every day.
2. Why is radon a problem?
The problem occurs when radon gas enters your home and gets trapped. Long-term exposure to high levels of radon can cause lung cancer. The Environmental Protection Agency estimates that lung cancer caused by radon exposure kills about 21,000 Americans every year.
3. How does radon get in your house?
The radon gas moves from the soil into a home. Although it can seep directly through pores in concrete, the worst entry points are gaps in walls and floors (see picture above). Any house, of any age, in any state can have elevated radon levels. It really depends on the way your specific house interacts with the surrounding soil. Your neighbor’s radon level may differ significantly from yours.
Testing your home from radon is the only way to know whether or not your house has unsafe radon levels.
4. How do you test your home for radon?
Conduct the test in the lowest livable area of your house that is regularly used 8 to 10 hours per week.
- Short-term tests (pictured below) These are useful to see if further testing is warranted. Most are activated charcoal-based or electret ion that measure radon levels for two to seven days. You mail the tests to a lab for the results. Short-term tests are available at home centers, hardware stores, and online retailers.
- Long-term radon tests (pictured below) These radon tests measure levels for 90 days to one year. Most, such as the AccuStar test, are based on alpha particle tracking. This is a more accurate indicator of average annual levels, which can vary significantly from day to day and month to month based on factors such as a drop in air pressure, gusty winds,variable soil moisture, and snow cover, which traps radon gases. Long-term radon tests are available through state radon agencies and online retailers.
- Continuous radon tests (pictured below) Electric monitors, such as the Safety Siren Pro Series digital meter in the photo (available from online retailers), plug into a standard outlet. These can be used for both short-term and long-term testing to give you a running average every day.
5. What should you do if your house has high levels of radon?
If an initial short-term test registers 4 picoCuries per liter (pCi/L) or higher, the EPA recommends doing a second radon test. A long-term test will give you the most accurate information, but a short-term test is acceptable if you need the results quickly, such as for a real estate transaction, or your first levels registered 8 pCi/L or higher.
If a second test registers above 4 pCi/L, consider taking steps to reduce radon levels in your home.
How do you lower radon levels in your house?
You can start by trying these easy repairs to reduce radon levels. These efforts alone rarely reduce levels significantly, but if your level is only slightly elevated, these repairs might make the difference. They will also make other radon reduction methods more effective and cost efficient.
- Caulk foundation cracks, construction joints, and other openings with polyurethane caulk.
- If you have a sump pump, install an airtight cover on it (choose one that allows access to your sump).
- Cover soil in crawl spaces with polyurethane plastic sheeting (with a minimum thickness of 6 mil, available at home centers) tightly attached to the walls.
- You can also try sealing concrete, although the EPA has found concrete sealers to be a temporary solution at best.
Once you’ve tackled these, retest. If levels are still high, consider installing a radon mitigation system yourself or hire a pro.
7. What’s a radon mitigation system and how does it work?
It basically involves ventilating your home by using PVC piping to draw radon gas up from the soil and out of your house.
The most effective system is a vent pipe placed in the sump pit (if you have a sump pump) or a hole made under your concrete floor slab. A special in-line radon fan is placed in the attic or outside the house to draw air through the vent and radon from under the basement floor. The easiest method is to run the vent out the side of the house and up to the eaves. (You can also run the vent up through the house and out the roof, which is a lot more work and cost, but it looks better).
Pros usually charge between a few hundred and a few thousand dollars to install a radon mitigation system, depending on your home and your radon levels. Your state radon office will have a list of qualified contractors.
If your house has high radon levels, it’s important to act, but don’t overreact. Risks from radon are cumulative, which means serious effects result from exposure to high levels over a long period of time. It is prudent to test radon levels and decide on a course of action. But you don’t have to move out of your house or hire the first contractor who can fix the problem. For more information, contact your state radon office.