Radon is a colourless, odourless and tasteless radioactive GAS formed by the breakdown of uranium. Radon is a natural radioactive material found in soil, rock and groundwater. Outside, radon is found in the air it is not a concern because it has been diluted to low concentration. Radon, in enclosed spaces, such as basements, can accumulate to dangerously high levels exposing inhabitants to radiation.
Significant increase in Lung Cancer risk has been identified with high level of Radon exposure. In particular Radon exposure AND smoking pose a serious risk to health. Whereas a lifelong smoker has a one in eight likelyhood of getting lung cancer, a lifelong smoker exposed to high Radon concentrations has a ONE IN THREE likelyhood of getting lung cancer. This is a significant effect.
Where does Radon come from?
First some background on Uranium decay
The Uranium isotope is not stable and goes through several intermediate products as it decays. Some of these intermediate products have long half lives ranging from 25 days to several billion years. Others decay in just a few days or seconds. Radon is one of the intermediate products of Uranium isotope decay and it has a half life of 3.8 days. Eventually it decays further and becomes stable lead.
Radon atoms are short-lived (3.8 days half life). Over the course of several days Radon becomes lead. While it is existing as RADON, it is a gas.
How does Radon get in a building?
Because Radon is a gas, it can seep from the ground into the air in a building mainly through the foundation, It can also be dissolved in ground water:
- Exposed soil in basements
- Cracks in basement floors and foundation walls
- Drains, sump pumps
- Construction joints
- Concrete blocks and porous foundations
- Loose fitting pipes
- Dissolved in well water
How do you determine Radon concentration?
Because we can't smell, taste or see it it has to be tested for. There are a number of ways of doing this. Professionals have equipment that can monitor the levels. There are also home tests. These work in various ways. The most common use a charcoal filter that accumulates radon. This is then sent to a specialized facility that can measure the Radon and report back the result. Other methods involve exposing a plastic sheet that gets etched, or exposing a charged surface and measuring the change of charge. There are also radon meters that get plugged in and give an average reading.
The concentration of Radon in homes has been found to vary a great deal even in very short time periods. It tends to be higher in winter. Not all the reasons for the wide fluctuations have been identified. Outside concentration is one factor. Water content and drainage of soil, temperature, and original concentration of Uranium, are only some of the factors.
Conditions inside the home such as ventilation, and the type of heating have a great deal of influence on radon concentration. Accumulation of Radon will be higher if you run many exhaust fans and the inside air pressure is lower than outside air pressure. Outside air including Radon gas from below soil level will be sucked in.
To obtain an accurate picture of Radon concentration in a home it is necessary to test over a long period, (3 months or more) or to take several readings over short periods. Concentrations tend to be higher in Winter because for one thing the house is not as well ventilated, and radon concentrations tend to be higher in the basement. Winter is therefore a good time to test and hopefully get a maximum reading.
Home basement testing in Winter will likely return a higher than average result and will give an indication of a potential problem Radon concentration.
How can Radon concentration be reduced?
Radon is a natural substance found in varying concentration in the soil. It is not likely that we can completely eliminate it. We can however reduce the concentrations to much safer levels.
There are several ways of reducing Radon concentration in a Building
- By ensuring a good air flow in the building the concentration can be diluted into a larger area. This occurs in hot air heating systems. Radon that would accumulate in a small area is diluted throughout the building.
- Outside air Supply
- Bringing fresh air from outside further dilutes the Radon concentration in a building. An intelligent balance has to be struck between keeping a home warm (or cool) and managing Radon concentration. Heat exchangers in ventilation system allows more cold outside air to be brought in while keeping warmth inside.
- Improving Basement impermeability.
- Radon gas seepage can be greatly reduced by cementing exposed soil in basements, filling in cracks and improving joints at the basement floor and walls, by caulking any loose fitting pipes to the outside and by enclosing sump pumps. Sometimes simple things such as painting the inside foundation can have a positive effect. Some surfaces are more porous than others such as old stone foundations and cement blocks.
- Construction Practices
- Coating the outside of the foundation, using vapour barriers, waterproofing surfaces all help decrease Radon concentrations. Choice and thickness of foundation material also has an effect.
- Managing exhaust fans.
- Exhaust fans, such as kitchen or bathroom fans, lower the air pressure inside a home compared to the outside. This sucks in air to replace the exhausted air and this new air includes radon particularly if the air sucked in comes from the basement (and the soil from outside the foundation). It is good practice to provide an easy fresh air entry point to replace the air being exhausted. Clothes dryer also suck air out and reduce inside air pressure.
- Fireplace or Gas furnaces
- These act as exhaust fans and create a low pressure area in the building which sucks in outside air and Radon. It's better to provide an above ground outside air supply rather than letting the air and Radon come in indiscriminately.
- Avoiding a Closed home
- Keeping a building closed up to help air conditioning or heating increases the risk of noxious substances accumulating including volatile organic compounds (VOX) and Radon. A balance has to be struck between the need for fresh air and the increased concentration of nasty chemicals in the building resulting from closed areas. Much has been written on Sick Building Syndrome mostly in relation to high rise accumulation of VOC but it has a Radon component.
Is Radon concentration the same in all localities?
Of course not. Some areas have more uranium in the soil and thus have greater concentration of Radon. The type of soil which allows for gas movement is also likely to have greater Radon concentrations. Porous open soil allow more air movement and thus more radon to move through.
Mr.Radon has a radon potential Canada Map Note that the Port Hope area has tested much higher than other area due to contamination from radioactive waste.
Some Radon Information Links
There are a great number of sites providing information on Radon. Most Canadian sources seem to be quoting the Government of Canada web information. Since there is a lot of research currently going on it is useful to re-visit the search at regular intervals. Products are coming on the market quite fast as well. Meters and testing devices, sealants for basements, fans and ventilation systems are example of these.
What to do if you suspect High Radon Concentration in your home.
Get your home tested. There are meters that give a read out, or test packages that need to be exposed then sent away for analysis.
Make sure that outside air can come in through an above ground window to minimize low air pressure in the home, and prevent air including radon from seeping in from the basement. By having vapour barriers, painted floors, caulked pipes and enclosed sump pump you reduce the number of entry points from the basement.
In an area where Radon concentrations are elevated, it might be necessary to bring in professionals who will install strong ventilation and help seal your home.
Conclusion of my Radon Research
This is what I took home from my couple of days of research on the topic of Radon contamination and health concerns.
- The health effect of Radon are important particularly if you are a smoker. Radon gas causes lung cancer. No other serious health effects have been linked to radon (yet). Drinking water with Radon is not a significant problem.
- I am concerned enough to have ordered a testing kit. In fact I ordered a monitor at a slightly higher cost and intend to keep a close eye on it for the next few months.
- I will increase outside ventilation particularly in 2 specific areas. In the basement near the gas furnace and hot water heater, and in the kitchen near the stove exhaust fan.
- I will complete the painting of the cement floor, and the parging and painting of my old house foundation to reduce porosity of the basement surfaces.
- An existing radon problem is completely manageable with relatively inexpensive procedures and modifications.
NOTE: I am NOT an expert on Radon, I would say I am an informed amateur. I spent a couple of days reading and digesting the information I found. Do your own homework, and have your home tested or buy a home test. If you think you have a problem get an expert in. If you smoke it is even more important for you to get informed. If you have a problem don't panic, it is a problem that can be solved and managed.