When and why to test indoor air for VOCs in Canadian buildings

Volatile organic compounds are a broad category. The term covers everything from benzene (a known carcinogen) to the terpenes released by a pine floor finish. Not all VOCs are equally concerning, and not every building needs testing. This article helps you decide when testing is warranted and what the process involves.

Common triggers for VOC testing in Canadian buildings ¶

The most common triggers are a renovation or new construction (off-gassing from adhesives, flooring, and paints), a complaint from occupants about persistent odours or symptoms, a known or suspected product spill, or a requirement under an occupational health and safety program. In some cases, a landlord or employer commissions testing proactively after installing new materials, to document baseline conditions before occupancy.

In Ontario, the Occupational Health and Safety Act does not specify numeric VOC limits for most workplaces, but it does require employers to take every reasonable precaution to protect worker health. A documented air quality assessment is one way to demonstrate that precaution has been taken.

Passive versus active sampling: which one applies to your situation ¶

Passive sampling uses a sorbent tube or badge that absorbs VOCs from the air over a set exposure period, typically 24 to 72 hours. It requires no pump or power source, which makes it practical for occupied spaces. The tube is then sent to the laboratory for thermal desorption and GC-MS analysis. Passive sampling gives a time-averaged concentration, which is appropriate for assessing chronic exposure.

Active sampling uses a small pump to draw a known volume of air through a sorbent tube over a shorter period, typically 15 minutes to 8 hours. It is better suited to capturing short-term peak concentrations, such as during a specific work process. Active sampling requires a calibrated pump, which the laboratory can supply or the client can rent from an industrial hygiene supplier.

Health Canada's residential indoor air quality guidelines ¶

Health Canada has published residential indoor air quality guidelines for a subset of VOCs, including formaldehyde (long-term guideline: 50 µg/m³), benzene (no safe threshold; minimise exposure), and naphthalene (10 µg/m³ long-term). These guidelines apply to residential settings; occupational exposure limits for workplaces are set separately by provincial authorities.

The laboratory report will compare results against the applicable Health Canada guideline where one exists, and will note where no guideline is available. For compounds without a specific guideline, the report will reference the detection limit and note whether the compound was detected.

If you are not sure whether your situation warrants testing or which sampling method applies, a brief conversation before you order sampling media can save time and money. Get in touch with us to talk through the specifics.