How Come Rain Increases Levels Of Radon?

Radon is a harmful, odorless gas that can be found anywhere, both inside and outside our homes. Weather changes can have a huge impact on the radon gas levels in your home, especially during rainy days. Although many other factors can cause a temporary increase in radiation levels, radon may be captured in the rain and brought to the ground. A scientific explanation behind this phenomenon is that radon gas tends to be at its highest level throughout the winter months. This article explains some of the reasons why rain increases the levels of radon. 

How Rain Increases Radon Levels

  • Air Permeability Of The Soil

Heavy rainfall loosens the soil, making it easier for radon gas that was previously trapped underground to escape.

radon detector in the rain

The amount of radon gas that is released into the air when it rains may vary depending on the air permeability of the surrounding soil. Clay and silt are low permeability soils that reduce the flow of radon gas leakage unlike high permeability soils such as sand and gravel. This means that if the surrounding area is primarily made up of sand and gravel, then more radon gas is likely to be released from the soil because a lot of rainwater can pass through easily.

  • Radon Gas Caught By Rainwater Droplets

The small amounts of radon gas present in the air could be potentially ‘caught’ by water droplets falling from the sky. This carries more radon towards the earth’s surface causing it to sink to the groundwater level beneath a home. Radon will be released once the infiltrated groundwater encounters the air in your home. This water can seep into your home through cracks in the basement wall or foundation exposing radon gas that was previously trapped in groundwater.

  • Frozen Ground Soil

When the ground becomes saturated with water from heavy rainfall, it becomes difficult for radon gas to find a path through the soil to the exterior of your home. Rain or storm causes lower air pressure around your home, causing radon to rise from the ground faster than normal. The pressure below the surface increases the level of radon gas entering your home because it is the easiest path for the odorless gas to reach the air. It enters the home through tiny cracks or openings in the foundation and basement walls.

  • Stack Effect

People tend to close their windows and turn on their HVAC systems when it rains. This creates a natural vacuum, which allows radon gas to flow from the soil beneath your foundation into the house or from cracks on your basement walls. Although the air pressure differentials in your house may not be large, they could significantly spike the radon gas readings over time. The greater the contrast between the frigid cold rainy weather and your cozy heated home creates the ‘stack effect’. This occurrence happens when you turn on the HVAC system to warm up the house. Therefore, the greater the heat level inside your home, the greater the amount of radon being drawn inside the house.

How to Protect Your Home From Radon

It is important to take necessary precautions to protect you and your family from the effects of radon during the rainy season. One of the things that can help is to seal up your home. As discussed above, radon can enter your house through cracks on the wall or the foundation. If you have trouble finding every possible opening for radon gas leakage, it is advisable to hire a mitigation professional to help with the task. You can also install a radon mitigation system if you have not installed one already. Although there are various radon mitigation options you can consider, one of the popular choices homeowners go for is an interior system comprised of a pipe that runs from your basement or garage to a radon fan installed in your attic. You can also look into other exterior options recommended to you by a radon mitigation professional.

Radon is a major concern, especially during the winter season because of greater air pressure differentials. All theories that explain how rain increases radon levels show that the primary ways this odorless, harmful gas enters a home are through cracks on basement walls and your home’s foundation. It is important to seal off any openings and install the most appropriate mitigation system to keep you and your family safe from radon.