The CARST and UoC publications are based upon the Health-Canada need for long-term average exposure rates. As the levels of radon can fluctuate hour-to-hour and day to day, and are also affected by the way the home is operated, long-term testing is the only means to accurately identify the average long-term exposure to radon.
This does not mean that short-term measurements are not effective. You needs to understand the reasoning for them.
- It is generally accepted that ANY exposure to radon is not healthy.
- It is also generally accepted that exposed to higher radon levels for longer periods of time increases the risk of contracting lung cancer as a result.
- Radon is a radioactive gas, produced as part of the radiation decay chain or uranium, which is pervasive through the planet (and the universe).
- As a gas, it moves from an area of high-pressure, deep underground, to an area of low-pressure, at the earths surface, and this movement is pretty rapid.
- The average background radon levels in most of Canada is around 35Bq/m3, so anything over that indicates a possible increased level of exposure.
- Homes, especially moden homes, are supposed to be sealed against infiltration of soil gases, of which radon is one.
With this in mind, any increase in radon level in a home over the average background level, regardless of the timeframe the levels are measured over, indicates that soil gasses, and in particularly radon, may be seeping into the home through cracks and fissures in the building envelope.
The important thing to recognise is that the precision of the measurements is based upon the equipment used. For OCRMI Inspectors, any ultra-short measurement MUST be performed using an approved constant radon monitor. These are highly accurate devices, unlike the devices discussed in the UoC publication. They also provide an hour-by-hour reading of not only radon, but also pressure and humidity. This helps identify if radon level changes are exacerbated by factors other than holes in the building.
the OCRMI measurement protocols were developed to provide home owners, and home purchasers, early detection that something might be defective in the building envelope, allowing radon to build-up to what would be considered dangerous levels.
Many people think that 200Bq/m3, being the Health-Canada recommended action level, means that anything below that is safe.
Health-Canada themselves are very vague, talking about “acceptable levels” and “increased risks with longer exposure”, but the truth is, nearly every health organization on the planets is of the opinion that there is no “safe” level of radon. Indeed, the World Health Organization in their key facts report on radon state “The lower the radon concentration in a home, the lower the risk of lung cancer as there is no known threshold below which radon exposure carries no risk.”
Our arguments against performing only a long-term test and only during the heating seasons are:
- During a real-estate transaction this is an impossible timeline.
- If there is a risk, the occupants are subjecting themselves to that risk longer than required.
- As Home and Property Inspectors we are focussed on building defects, not long-term, average, health risks.
- Any increase in radon, above the background average indicates that the risk is there, and that the soil gas prevention mechanisms in the building are defective in some way.
Looking at it another way. If you were going to buy a boat, and on inspection of the interior you found water at the bottom of the hull, would you want the leak found and fixed, or would you rely on the bilge pumps to keep the boat dry?
If the background average radon level is 35Bq/m3 and the interior level, even for 2 hours is shown to be 80Bq/m3 (that’s above the background level) or 120Bq/m3 (that’s above the World Health Organisation reference level) or 160Bq/m3 (that’s above the U.S. recommended action level) or 220Bq/m3 (that’s above the Health-Canada action level) wouldn’t you want to ensure something was done about it?
Answer that question, and you’ve answered your posted question.