Radon & Your Home

What is Radon?
Radon is a radioactive gas that is colourless, odourless and tasteless. It is formed by the breakdown of uranium, a natural radioactive material found in soil, rock and groundwater.

Radon escapes from the ground into the outdoor air. It is diluted to low concentrations and is not a concern. However, radon that enters an enclosed space, such as a home, can sometimes accumulate to high levels. Radon breaks down to form additional radioactive particles called “progeny” that can contaminate the air you breathe.

Concern in Canada about indoor radon levels began in the mid-1970s. Some homes in communities where uranium ore was either mined or processed were found to have elevated radon concentrations. After this discovery, Health Canada surveyed the radon levels in 14,000 homes in 18 cities across Canada. Also, some smaller communities have been identified by provincial government agencies as having the potential for high radon levels in dwellings.

The majority of homes surveyed showed low concentrations of radon. However, a small but significant minority of homes in some locations were found to have high levels.

What is the Risk?
The only known health risk associated with exposure to radon is an increased risk of developing lung cancer.

Radon gas and radon progeny in the air can be breathed into the lungs where they break down further and emit “alpha particles”. Alpha particles release small bursts of energy which are absorbed by nearby lung tissue. This results in lung cell death or damage.

When lung cells are damaged, they have the potential to result in cancer when they reproduce. Cancers caused by radioactivity are started by chance and not everyone exposed to radon will develop lung cancer. The time between exposure and the onset of the disease is usually many years.

Your risk of developing lung cancer from radon depends on the concentration of radon in the air you breathe and the length of time you are exposed.

Until very recently, the estimate of the risk from radon in homes was uncertain. However, two recent independent studies in North America and Europe have confirmed that the lung cancer risk extends downward to radon levels as low as 200 Bq/m3.

What is the Effect of Smoking?
Smoking is the major cause of lung cancer – it is responsible for about 90 per cent of all lung cancer deaths in males and females.

The National Cancer Institute of Canada estimated deaths from lung cancer in 2006 as: 10,700 men and 8,600 women. In 10 per cent of these cases, radon would have caused the lung cancer.

Exposure to radon and tobacco use may combine to increase the risk of lung cancer. Research has compared the cancer rates in smoking and non-smoking uranium miners. Results indicate that smoking promotes earlier development of lung cancers that may have been caused by radon.

Not smoking is the most effective way you or your family can reduce the risk of lung cancer.

A Personal Evaluation of Exposure
Besides smoking habits, there are other living patterns that could influence your assessment of risk and the need to take action. Consider these questions to help evaluate your personal exposure:

• How much time do your family members spend at home? The assumption is that 75 per cent of a person’s time is spent at home.
• Do you have bedrooms or a home office in your basement? Radon concentrations tend to be greater on the lower levels of a home. A person who sleeps or spends much of his/her waking hours in the basement is exposed to more risk than others who occupy higher levels in the same house.
• How long will you live in your home? The guidelines in this booklet are based on an exposure period of about 70 years. Consider the amount of time you expect to live in your home.

Also consider that taking action to reduce radon in your home may have other benefits:

• Mold and odour problems that can result from moisture and soil gas contaminants entering your home are often reduced by radon reduction work.
• Sealing major cracks, holes and gaps in foundations can reduce cold drafts, lower energy bills and keep insects out.
• Sealing a sump will reduce both radon entry and the risk of injury to small children.

The Canadian Guideline for Radon
There is no regulation in Canada that governs what is deemed to be an acceptable radon level in a home. It is the choice of each homeowner to determine what level of radon exposure they are willing to accept.

Health Canada, in conjunction with the provinces and territories, developed the following guideline to indicate when remedial action should be taken. This guideline was approved by the Federal Provincial Territorial Radiation Protection Committee in October, 2006:

• Remedial measures should be undertaken in a dwelling whenever the average annual radon concentration exceeds 200 Bq/m3 in the normal occupancy area.
• The higher the radon concentration, the sooner remedial measures should be undertaken.
• When remedial action is taken, the radon level should be reduced to a value as low as practicable.
• The construction of new dwellings should employ techniques that will minimize radon entry and facilitate post-construction radon removal, should this subsequently prove necessary

The average level of radon in outdoor air is about 10 Bq/m3. However, levels can occasionally reach several times this amount for short periods of time. Indoor radon levels typically range from about 30 to 100 Bq/m3 with an average concentration of 45 Bq/m3. However, in some locations radon can readily exceed 200 Bq/m3, and in a few cases levels have been found as high as 3000 Bq/m3.

Reducing indoor radon levels to be no more than outdoor levels is not yet technologically achievable. However, most homes today can be reduced to 75 Bq/m3 or less.

How Radon Can Enter Your Home
During much of the year, the air pressure inside your home is lower than in
the soil surrounding the foundation. This difference in pressures draws air and
other gases in the soil, including radon, into the home.

Soil gas containing radon can enter a house any place it finds an opening where the house contacts the soil. These openings can be present even in well-built and new houses.

Potential entry routes for radon in homes with poured concrete foundations
include:

• exposed soil or rock in crawl space
• cracks or flaws in the foundation walls
• around utility penetrations and support post
• hollow subjects such as support posts
• cracks or flaws in floor slab
• floor/wall joints
• floor drains & sumps

Homes with concrete block foundation walls can have other entry routes such as:

• missing mortar between bricks
• unclosed voids at the top of exterior walls
• unclosed voids at the top of interior block walls which penetrate the floor slab
• cracks through the blocks or along mortar joints
• floor/wall joints
• pores in the face of blocks

Homes with less common types of foundations (e.g., concrete slab-on grade, stone, pressure-treated wood) may have other entry routes where openings or paths exist between the house and the soil. In many homes, regardless of the foundation type, some entry routes will be hidden. For example, they may be concealed by panelling, carpeting, appliances, wood framing or other objects.

In a few areas, large amounts of radon can be found in groundwater from private or small community wells. It can then be released into the air in a home when the water is agitated by activities such as showering, clothes washing or cooking.

Instead of wells, the water supply for larger communities is often drawn from open bodies of water. These sources tend to be low in radon.

Except in a few unusual cases, building materials used to construct a house are not a significant source of radon.

Which Homes Have a Problem?
Almost all homes have some radon. The levels can vary dramatically even between similar homes located next to each other.

The amount of radon in a home will depend on many factors such as:

• Soil Characteristics – Radon concentrations can vary enormously depending on the uranium content of the soil. Also, radon flows more easily through some soils than others.
• Construction Type – The type of home and its design affect the amount of contact with the soil and the number and size of entry points for radon. It also affects the rate of exchange of outdoor and indoor air.
• Foundation Condition – Foundations with numerous cracks and openings have more potential entry points for radon.
• Occupant Lifestyle – The use of exhaust fans, windows, fireplaces, etc. influences the pressure difference between the house and the soil that draws radon indoors. These factors also influence the rate of exchange of outdoor and indoor air.
• Weather – Variations in weather (e.g., temperature, wind, barometric pressure, precipitation, etc.) can affect the amount of radon that enters a home.

Because there are so many factors, it is very difficult to predict the radon level in a home.

The only way to determine whether your home has high radon levels is to test for it.

Contact your REALTOR at Coldwell Banker Vantage Realty for more tips and advice on what you can do if you have concerns of Radon in your home.

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