... continued from page 53.
She says that along with the data from population centers, the state is still trying to reach out to smaller communities and villages to gain more understanding of radon levels in other parts of Alaska.
For buildings constructed on top of piles or stilts, allowing air movement underneath, there are no reported increases in radon levels. Homes with basements below ground face higher risks. In northern areas underlain with permafrost, building on stilts or pilings is common, allowing for variations in the permafrost.
Much of northern Alaska is underlain with “continuous permafrost,” in a solid layer, but many lower regions have “discontinuous,” “sporadic,” or “isolated” sections of permafrost. Athey says that as the atmosphere warms, continuous and discontinuous permafrost lines will move northward.
“Places that used to be discontinuous permafrost or even continuous permafrost down the road are going to be available for people to build on,” she says, “ and that’s going to open up new land for people so they might be building with more traditional techniques with cross bases and basements.” These techniques, popular in the Lower 48, can increase radon levels indoors.
Avoid putting out a ‘welcome mat’ for increased indoor radon
An additional hazard in bitterly cold climates is that a home’s heating system can pull radon out of the ground and into the home. As hot air rises, heaters can create negative pressure, drawing gases up from the ground.
“In Alaska in the winter time, particularly when people are running their heaters, the stack effect happens, where air in the house that is hot goes up and out of the house, and that actually creates a negative pressure environment in the house and draws in ground gases.” The result “creates an environment that really invites radon into the home.”
She pointed out that running things like stove and bathroom fans and heaters will pull out hot air and exhaust. “The air has to be made up from somewhere, and if your house is built very tightly because you want to keep your house warm, but the foundation has cracks, that air makeup is going to come from the ground, and that’s where the radon is,” Athey says.
When homes or buildings test high for radon, a variety of methods can help mitigate the radon level. Sometimes, sealing basement cracks, joints, and seals around pipes will help reduce radon levels, but at other times a mitigation system involving ventilation or pressurization may be necessary.
However, building houses to be radon-resistant from the start is the most effective and least expensive way to control for radon, according to Athey.
“Radon-resistant home construction is very important, and that’s something that we try to highlight in Alaska, and it’s a lot cheaper to install radon mitigation from the get-go when you’re building your house than to try and retrofit and mitigate a problem that’s already there,” Athey says.
The study authors note this paper is an initial study, and they say more studies are needed to model variations in radon, building ventilation, speed of thaw, soil compaction, and other factors.
However, their work serves as a warning that thawing permafrost may have a wide range of impacts on people’s health and well-being, bringing more awareness to this little-known issue.
“Education and outreach is very important because a lot of people in Alaska don’t know about radon,” Athey says.
Continued on page 55 ...
54