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Radon is a colourless, odourless and tasteless radio active GAS formed by the breakdown of uranium. Radon is a natural radioactive material found in soil, rock and groundwater. Outside when 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 in some circumstances accumulate to high levels.

Serious increase in Lung Cancer risk has been idendified 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.

How does Radon get into a Building?

First a bit of background about 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 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 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
  • disolved 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.

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, temperature, original concentration of Uranium, are only some of the factors.

Conditions inside the home such as ventilation, and the type of heating are factors.

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, and tend to be higher in the basement. It 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 idication 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.
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 sufaces 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 including Radon. 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. Its 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.

Preliminary Canadian Radon map showing areas of higher concentration Note that the Port Hope area has tested much higher than other area due to contamination from radio active waste.

Some Radon Information Links

Radon Detect sells Radon Detectors and monitoring instruments online.

Government of Canada info on Radon

How things work has an interesting article

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 alot 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.

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 but not much more. 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.
  • A 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.

Nick Boothby, Maddy Dennett and Greg McDowell
REALTORS® / Salespersons

Christine DeMerchant Unlicenced Support Person
Real Estate Homeward, Brokerage
1858 Queen St. E., Toronto, On, M4L 1H1, Canada
tel: 416-698-2090   fax: 416-693-4284
Maddy's cell: 416-951-5507   Greg's cell: 647-984-3065
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