Healthy Indoors Magazine
Issue link: https://hi.healthyindoors.com/i/778725
Healthy Indoors 23 pathway into the home, and a negative pressure differential from the inside of the building to the soil. Radon is an equal opportunity pollutant, so every home has the potential to be a high radon home. What your neighbor's radon level is has no bearing on what your radon level is. Most North American soils and rocks have some trace amounts of uranium in them; it is the strength of that source that is variable. Pathways into the home are almost too many to list but some major ones are exposed soil crawlspaces, sump pits, curtain drains from basement to soil, un- trapped floor drains, box outs for HVAC system drains, cold joints between basement slab and basement walls, hollow block walls, and plumb- ing and electrical piping that has not been sealed. It only takes an aggregate 1 square cm opening to the soil if you have high source strength to have elevated radon levels in your home. Radon seeps into buildings because there is a pressure differential between the building and the soil that surrounds it. To explain this in non- technical terms, I often ask people to think about a soda pop cup. I ask them to imagine them tak- ing a hold of the top of the cup with the lid off and then imagine it being pushed down into a bucket of water without letting the rim of the cup go un- der the water. I then ask, why is the water trying to get into the cup? Because there is more pres- sure in the water surrounding the cup than there is in the air inside the cup. What would happen if there were a couple of tiny holes in the soda cup? Yes, it would fill up. What happens when we stick a house with a basement into the soil? Yes, the soil gas will seep in. You might ask: My home is slab on grade so I am safe, right? The next thing we must consid- er is the stack effect, when the warm air in a home comes up against the underside of the ceiling, it migrates through pulling on the whole building and the soil and creating a stack effect on the whole building. So, sorry, no, you are not safe. The only way to know your radiation exposure from radon is to test your home or workplace for radon. Testing for radon is simple: bring in a cer- tified radon testing professional, have a proper test conducted and then you will know. If you are more frugally minded and can follow detailed in- structions you can buy a test kit from the internet, or even your local big box store. Remember to Becquerel's per cubic meter (Bq/m³). Yes, we use different measurement systems in the two coun- tries but they have a mathematical relationship 1 pCi/l = 37 Bq/m³. Radon gas is responsible for 37–50 percent of the average North American's exposure to ra- diation. This is based on average indoor levels of radiation from radon of 1.3 pCi/l or 48 Bq/m³ in Canada. If the radiation caused by radon in your home/workplace measured about 4 pCi/l or 150 Bq/m³ you would be at a significantly higher ex- posure to radiation than the general population. That's what the fuss is all about. "Radon is the #1 cause of lung can- cer for non-smokers. Elevated radon is found in one out of 15 homes na- tionally, and the only way to know if a home has high levels is to test it." — Henry Slack, Indoor Air Coordinator EPA Southeastern Office, Atlanta, GA https://blog.epa.gov/blog/tag/cancer/ Action levels recommended in the U.S. by the Environmental Protection Agency (EPA), in Can- ada by Health Canada, and by the World Health Organization (WHO) all suggest different action or reference levels. In the U.S. the EPA action level is 4 pCi/l (148 Bq/m³). The EPA also recom- mends that Americans consider fixing their home for radon levels between 2 pCi/l (74 Bq/m³) and 4 pCi/l (148 Bq/m³). In Canada, Health Canada recommends mitigation at 200 Bq/m³ (5.3 pCi/l). The WHO recommends that a decision to miti- gate should be made at 100 Bq/m³. Whether a home or building has radon in it is dependent on three things: a radon source, a