Healthy Indoors Magazine
Issue link: https://hi.healthyindoors.com/i/1076124
Healthy Indoors | 43 In our homes, as we know, hot air rises, which puts our floor slabs at a lower pressure. This tends to draw air in through cracks in the slab. Sealing the slab is not enough to prevent radon entry; instead, contractors install a radon removal system. This is usually a pipe that goes below the slab and through the roof, or up the exterior of the house. Most systems also include a fan in the attic (or on the exterior) to actively draw the air up the pipe (sub-slab depressurization). How do we know the risk? Well, it's radioactive, so can- cer is likely. Radon has also caused cancer in animal stud- ies. More importantly, a set of studies used data from urani- um miners, who were exposed while mining. The evidence (contained in the Biological Effects of ionizing Radiation (BEIR) studies), is unmistakable: radon causes cancer in humans. The greater the dose, the more cases of cancer. EPA estimates that around 15% of homes have radon levels above 4 pCi/L. Unfor- tunately, thousands of new homes are built every year without any design for radon removal, even though it is much cheaper to install when under construction. Why not test the soil before building? Because no one has done so suc- cessfully. Soil tests, while seeming logical, have failed to predict which homes will contain radon, in part, because we can't predict a structure's pressure dif- ferences very well until it's built. It is easier and cheap- er to build a home to be ra- don-resistant, with the ex- haust pipe installed when it's built, than it is to defer to putting a radon system in later. Every January, EPA celebrates Radon Action Month with messages encouraging everyone to test their home. You cannot know if radon is present unless you test, and it's been found in every state, and even in high-rise condo buildings! In some cases, it's coming from the concrete, and many buildings have no outside air ventilation to remove it. So, please test your home (if you've not done so within the past few years) and fix it if you find high radon. Henry Slack retired from EPA Region 4 in Atlanta after 27 years in the IAQ program, helping people and agencies in the southeast understand IAQ issues. He has spoken numerous times for IAQA chapters and for the IAQA Na- tional Convention. A mechanical engineer, he has been an ASHRAE Distinguished Lecturer since 2014.