Why is Radon a Health Issue?
Radon is a colorless and odourless radioactive gas that is a product of the radioactive decomposition of uranium. Radon is a naturally occurring substance, but when it is in an enclosed space, it can accumulate to concentrations that pose a health risk. Exposure to high concentrations of radon has been linked to an increased risk of developing lung cancer, and radon gas exposure is the second leading cause of lung cancer after smoking. A number of studies in recent years have shown that a significant number of Canadians are living in homes with radon levels above the current Canadian guidelines. In 2012, Health Canada released the Cross-Canada Survey of Radon Concentrations in Homes final report indicating that 6.9% of Canadians are living in homes with radon levels above the guidelines. Early results from a 2016 Calgary study being undertaken by researchers is suggesting that as many as one and five homes are over the maximum acceptable limit.
Health Canada recommends that remedial measures be undertaken wherever the average radon concentration exceeds 200 Bq/m3 in the normal occupancy area. The World Health Organization (WHO) recommends a lower annual average concentration of 100 Bq/m3 as a threshold.
Measuring Radon Levels
Radon tends to be heavier than air and given that most of the radon in homes is from the soil upon which the building stands, Health Canada has recommended that radon testing be done below the third floor. The concentrations of radon in the indoor environment can vary significantly over time. For this reason, long-term measurements typically of 3-12 months are recommended. Testing for radon for less than three months is not recommended. Long-term radon measurements can be done with an alpha track detector, an electret ion chamber, or a digital detector.
In an alpha track detector, the alpha particles from radon and its decay products strike a special plastic or film, creating damage tracks and at the end of the testing period, the film is analyzed by a laboratory. In an electret ion chamber, there is an electrostatically charged disk detector, which experiences a reduction in charge as a result of the ionization from the decay of radon. The electret can be read in the home using a special device or sent to a laboratory for analysis. A digital detector uses an ion chamber, and after an initial measurement period, the device will display the average radon concentration continuously.
Reducing Radon Concentrations
Radon levels in a building can be reduced by:
Mould is a commonly found problem in homes and buildings and it affects people differently. For some individuals, it can lead to allergic reactions including rashes, coughing, eye irritation, or respiratory conditions including asthma in children. In extreme cases, exposure to certain types of toxigenic moulds such as Stachybotrys chartarum has been linked to more serious chronic health issues (though this is an area where research is ongoing). While exposure to mould spores is unavoidable, factors in the home can lead to greater concentrations of allergenic and toxigenic mould. In some cases, mould issues indoors have become so severe that residents are forced to leave their homes until the problem is addressed. Early detection and remediation is critical to avoid more serious and costly problems down the line.
Factors that Lead to Mould Growth
Mould requires moisture to grow. Mould colonies tend to form when mould spores in the air land in areas of high moisture such as:
What to do When You Suspect Mould
Mould is sometimes detectible by sight or smell (a damp odour), but it is often hidden and its presence unknown without indoor air quality testing. Unfortunately, there is no way to tell how bad a mould problem is for two reasons. First, testing is required to determine the type(s) of mould present. Second, often the mould problem goes beyond the surface and exists behind walls or under flooring. If you see or suspect abnormal mould contamination, you should contact professionals to assess and remediate.
It is important for you or your professional to determine the underlying reason for the mould growth. Without first indentifying and fixing the moisture source supporting the mould growth (e.g., condensation or basement leak), your problem will likely continue to persist. Remediation and clean up strategies for mould vary depending on the type of mould and the degree of contamination. In cases of small surface mould, mould can be removed with scrubbing and disinfection with a simple 50% vinegar solution. Commercial cleaners are also available, though not always necessary.
For larger problems, professional advice is typically warranted as the size of the cleanup effort will vary depending on the extent of contamination. When undertaking mould remediation, it is important to have the right personal protection including N95 masks (or better), non-porous gloves, protective goggles and a protective suit.
Preventing Mould Growth and Proliferation
Some effective strategies to prevent mould issues in the home include: