Q: This isn’t a question, but a comment/suggestion. I read one of your columns on your website talking about taking care of the small stuff when it comes time to list your home for sale.

You advise people to get a home inspection before they market their home. And, you suggested that they can make all the repairs to the home before they list it for sale. You also said that you can use the presale inspection as a marketing strategy.

I wanted to add to your suggestions. I would also advise having a long-term radon test (90 days to one year) done on a home before homeowners market the home for sale. This is much better than the short-term test after signing a contract. Long-term tests are more accurate, and if you need to install a mitigation system, it allows the seller time to shop around.

A: Thanks for your suggestion. Sounds like you’ve got some first-hand experience with radon causing problems for a home seller.

First, a refresher on radon. Radon is an odorless and colorless gas that can cause extremely serious health problems, including lung cancer. In fact, it is the leading cause of lung cancer in non-smokers. Children are at a much greater risk, according to the North Carolina Department of Health and Human Services.

The gas comes into homes from underground and seeps in through cracks in the basement floors or where the walls and floors join. When radon does get in, the levels can increase until they become a health hazard. You can’t smell it or see it. That’s partly what makes it so dangerous. The EPA recommends that homeowners take action when the levels of radon are greater than 4 pCi/L (or 150 Bq/m3). These are the customary measures used to determine the level of radon: picocuries per liter or becquerels per cubic meter. It’s a way to measure the amount of radon in a volume of air.

The EPA has a map that assigns three levels of radon to areas in the U.S. Most of the Midwest, upper Midwest and Northeast states tend to have higher levels of radon than the South or West Coast.

If you live in an area where there could be higher levels of radon, test to see if your home’s radon levels are below the EPA recommended levels. Our reader recommends taking a longer term approach to reading radon levels. From our reading of various sources, and talking to various contractors through the years (and testing our own basement), radon levels can fluctuate greatly depending on the weather and even the time of season. The levels may vary seasonally or be higher or lower in different years, so you might want to test every so often.

Radon inspectors will typically place radon readers in basement levels and first floor levels of homes for around 48 hours or so before taking them down and evaluating the test. Homeowners will be asked to close air ducts, windows and doors in areas being tested. In essence, they want the monitored rooms to be sealed off to let the radon accumulate to get the level of radon in a closed environment.

What our reader is saying is that a two-day test may sample the home when radon levels are at their highest or lowest but may not provide an overall accurate reading for the home. In Sam’s deals where radon levels are above 4.0 pCi/L, the homeowners usually install a radon remediation system.

In the most basic sense, a radon remediation system is one that pulls air out from below the foundation and draws it to the exterior. The reasoning is that the system will catch the radon gas before it infiltrates the home. These systems have a fan that continually pulls air out at all times. In homes with sump pumps, the system may cover the sump pump area and pull that air out.

A long-term test should provide additional information on the long-term levels of radon in a home, as our reader suggests. But, it’s unclear what will satisfy a prospective buyer. You might put in one system and think it works perfectly well. But a buyer might hire a radon inspector who tests when the levels are high, and you’ll be asked to install a different system.

If you test over time and discover that you have high radon levels, you might want to consider installing a remediation system. Even if you don’t have young children in the house.

Ilyce Glink is the CEO of Best Money Moves and Samuel J. Tamkin is a real estate attorney. Contact them through the website ThinkGlink.com.