Old man winter is knocking at the door and he might be bringing radon with him. In homes that are located in cold weather environments, radon levels can increase during colder months. This often-overlooked issue with radon gas is potentially one of radon’s greatest threats.
If you are like me, you hunker down for the cold months. When not at work, you tend to spend more time in the house enjoying a book, catching your favorite sports event or watching a movie. The house is our safe haven from the harsh weather outside. But is it really that safe? Radon levels in many homes tend to be higher during the winter months. Here are a few of the reasons why:
1. Greater stack effect can draw more radon into the home. During the winter, stack effect tends to be greater as the warm air within the house rises and escapes to the colder air outside. As air escapes, the house has to replace the air to equalize pressure. Many houses get new air through drafty doors and windows. Houses also get new air from the soil they are built upon. The air from the soil can be pulled in through cracks in the concrete, plumbing pipe penetrations, sump pump pits, floor drains, crawlspaces and any other areas that have contact with the soil. This new air that enters can contain radon gas.
2. Greater concentrations of radon can enter the home during winter months. Radon enters the home from the soil below it but more radon escapes through the soil around the home and dilutes into the fresh outdoor air. During winter months, in cold climates, the ground in our yards can freeze and be covered with a layer of snow. This creates a blanket effect that can trap radon in the soil around the house. Since less radon in the soil is able to escape through the frozen ground in the yard, the house may be pulling in higher concentrations of it.
3. Closed house conditions during the winter can keep radon gas levels from being diluted by fresh air. During warmer months some dilution can occur when you open the windows to bring fresh air in. During the winter the windows are usually shut to keep the house warm which can effect the concentration of radon in the house. Note: Opening windows can have the opposite effect by increasing the home’s stack effect and therefore pulling more radon in.