What is Radon?
Radon is a toxic radioactive noble gas, which is invisible, colorless, odorless and tasteless.
It is found in soil, rock and building material in and around your home. Radon gas is slowly released from underground by radium that breaks down in soil, rocks, and water. Radon gas seeps into our basements through cracks, pipes, holes and other openings in our walls and floors.
Radon gas, or its radioactive decay products are inhaled into your lungs. These decay products can stick to the lung tissue and cause lung cancer. Radon continues to decay and form other radioactive particles that cling onto the lung wall.
Energy is released during the decay, which causes damage to the lung cells. The damaged cells become cancer cells when they improperly repair themselves.
It is found in soil, rock and building material in and around your home. Radon gas is slowly released from underground by radium that breaks down in soil, rocks, and water. Radon gas seeps into our basements through cracks, pipes, holes and other openings in our walls and floors.
Radon gas, or its radioactive decay products are inhaled into your lungs. These decay products can stick to the lung tissue and cause lung cancer. Radon continues to decay and form other radioactive particles that cling onto the lung wall.
Energy is released during the decay, which causes damage to the lung cells. The damaged cells become cancer cells when they improperly repair themselves.
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How radon breaks downThe figure on the left shows the different elements involved when uranium breaks down, eventually forming radon gas and other products (also known as “radon daughters”).
The time periods indicated in each box represent the half-lives of each radioactive element. The half-life is a commonly used measure that quantifies the length of breakdown of radioactive particles. It corresponds to how long it takes for a given amount of each element to break down to half the original amount. |
Health risks of radon gas
Radon gas exists everywhere in the environment. However, it is a health concern when it accumulates to high levels in buildings because, due to its radioactive nature, exposure to high levels of radon gas increases the risk of developing lung cancer.
The risk of developing lung cancer from radon exposure depends on:
As an example, the chances of developing lung cancer for a:
The risk of developing lung cancer from radon exposure depends on:
- How much radon you are exposed to,
- How long you are exposed (length of time),
- Whether you smoke tobacco or not.
As an example, the chances of developing lung cancer for a:
- Lifelong smoker: 1 in 10
- Lifelong smoker + radon: 1 in 3
- Non-smoker + radon: 1 in 20
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Recently, Dr. Goodarzi gave an excellent Tedx talk on radon gas and his project. In a well delivered presentation he makes the dangers of living in a home with high radon levels very clear and easy to understand.
Without pulling any punches on the severity of lung cancer, Dr. Goodarzi compellingly addresses radon in a manner digestible by everyone regarding the dangers or what exactly a high radon level means for them and their families. |
Radon guidelines in Canada
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In Canada, the concentration of radon in the air is measured in units of Becquerels per cubic meter (Bq/m3). Basically, 1 Bq/m3 corresponds to one radioactive disintegration per second in one cubic meter of air.
Health Canada and other government agencies in the world have recognized the risk posed by radon gas. These governments have developed guidelines for indoor radon levels known as action levels. This means that radon levels in homes and buildings are recommended to be below 200 Becquerels per cubic metre (Bq/m3). Any level of 200 Bq/m3 and above should be fixed (radon mitigation). Based on this guideline, indoor radon levels are interpreted as follows: |
Government of Canada - Radon: What You Need to Know
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How does Radon Enter a Building?
The most common source of radon gas is the soil. Other less significant sources of radon are well water, and some building materials that may have some trace amounts of radium and uranium (e.g. some granite counter tops, stone features).
A house can act like a vacuum for gases that emanate from the soil. The air pressure inside your house is usually lower than in the soil surrounding the foundation. This is a conducive condition for soil gases like radon to come into a home.
The difference in pressure between the soil and a home can also be caused by natural air movement, particularly in the cold season when warm air from the house moves outside, also known as stack effect. The use of air exchangers, exhaust fans and clothes dryers can also contribute to this effect.
When air is pushed out of the house, outside air is pulled back in to replace it. Much of the replacement air comes from the ground surrounding the house and brings gases such as radon with it.
A house can act like a vacuum for gases that emanate from the soil. The air pressure inside your house is usually lower than in the soil surrounding the foundation. This is a conducive condition for soil gases like radon to come into a home.
The difference in pressure between the soil and a home can also be caused by natural air movement, particularly in the cold season when warm air from the house moves outside, also known as stack effect. The use of air exchangers, exhaust fans and clothes dryers can also contribute to this effect.
When air is pushed out of the house, outside air is pulled back in to replace it. Much of the replacement air comes from the ground surrounding the house and brings gases such as radon with it.
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Radon gas can enter a house at any place it finds an opening where the house contacts the soil. Here are some examples of potential entry points:
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The concentration of radon gas in indoor air depends on:
The ease with which radon gas can move through the soil can be influenced by many different factors; porosity of soil, moisture content in soil, building structure and other factors that affect air pressure differentials.
- The number of openings in a house that can let in radon.
- The strength of radon source in the soil.
- The ease with which the radon can move through soil and building foundation, walls or any other openings.
The ease with which radon gas can move through the soil can be influenced by many different factors; porosity of soil, moisture content in soil, building structure and other factors that affect air pressure differentials.
Number of homes with high radon levels (200Bq/m3 and above)
A recent Health Canada study estimates that about 7% of Canadian homes (~600,000) have high radon levels above the recommended guideline.
Can you predict the Radon Level in your home?
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Given the number of variables involved, every house or building has unique circumstances that can affect radon levels. A number of factors can affect radon levels in a building.
Radon levels have also been shown to vary even by next door neighbours. A recently reported case in Quebec shows radon tests done in two neighbouring homes, where one home had radon levels at 125 Bq/m3 and the next door neighbour had 20,653 Bq/m3! Some people argue that older homes have are more likely to have entry points for radon and thus are at more risk than newer homes. However, newer homes tend to be more tightly sealed for energy efficiency. This means that radon gas can easily accumulate in the new home. |
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New Home Regulations & Radon
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Alberta building codes requires that ALL NEW HOMES permitted after November 1, 2015 must have a Radon Rough-in for a sub-floor depressurization system. But the builder is not required to install the full mitigation system.
Once the home is occupied the home should be TESTED FOR RADON. We work directly with New Home Builders in the area to ensure their clients have a Certified Radon Measurement Professional at hand to come in and perform the Radon Inspection. We want the public to understand that all homes contain Radon, the question is how much. It doesn't mean your home was poorly built if there is Radon in your home. We also want to ensure that everyone is aware that Radon is a FIXABLE problem. |
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