Indoor air in residential premises may contain various volatile organic compounds (VOCs) which may pose a risk to human health at certain exposure concentrations. Therefore, Health Canada has specified exposure limit values for a small number of VOCs such as benzene, formaldehyde, naphthalene, toluene and acetaldehyde in its Residential Indoor Air Quality Guidelines. These VOCs are prioritised in the assessment as they are often present in indoor air and pose potential health risks.
These Residential Indoor Air Quality Guidelines were published in 2006. They contain information on
- known health effects of indoor air contaminants
- indoor sources of air contaminants
- recommended exposure limits
- recommendations to reduce your exposure to pollutants
For the time being, testing to ensure compliance with the Canadian guidelines is voluntary.
In the summer of 2021, the Formaldehyde Emissions From Composite Wood Products Regulation: SOR /2021-148 was also published, which defines requirements for wood-based materials (wood-based panels, laminated products and finished products whose components include previously mentioned elements). (A link to the regulation can be found under the “Related Links” tab on this page). On January 7, 2023, this is scheduled to go into effect for wood-based panels. In 2028, the regulation will come into force for laminated products.
To assist healthcare professionals, including those involved in the development of standards and who may need to assess the potential risk of exposure to other VOCs in indoor air, Health Canada further developed screening values known as Indoor Air Reference Levels (IARLs). The IARLs are intended to complement Health Canada’s Residential Indoor Air Quality Guidelines.
Residential Indoor Air Quality Guidelines: recommended exposure limits
The recommended exposure limits of the Residential Indoor Air Quality Guidelines refer to a short-term exposure limits (usually one hour) and a long-term exposure limits (usually 24 hours).
||Short exposure duration||Long exposure duration|
|Acetaldehyde||after 1 hour ≤ 1420 μg/m3
||after 24 hours: ≤ 280 μg/m3|
|Acrolein||after 1 hour ≤ 38 μg/m3
||after 24 hours: ≤ 0.44 μg/m3|
|Carbon dioxide||after 24 hours: ≤ 1800 mg/m3|
|Carbon monoxide||after 1 hour: ≤ 11.5 mg/m3
||after 24 hours: ≤ 28.6 mg/m3|
|Formaldehyde||after 1 hour ≤ 123 μg/m3||after 8 hours: ≤ 50 μg/m3|
|Naphthalene||after 24 hours: ≤ 10 μg/m3|
|Nitrogen dioxide||after 8 hours: ≤ 170 μg/m3||after 24 hours: ≤ 20 μg/m3|
|Ozone||after 8 hours: ≤ 40 μg/m3|
|Radon||Exposure limit: ≤ 200 Bq/m3|
|Toluene||after 8 hours: ≤ 15 mg/m3||after 24 hours: ≤ 2.3 mg/m3|
|Xylol||after 1 hiour: ≤ 7200 μg/m3||after 24 hours: ≤ 150 μg/m3
*unless otherwise stated
Guidance documents for specific indoor air contaminants
In some cases, the determination of an exposure limit from the available scientific evidence is not possible. When this happens, a guidance document that focuses on actions to reduce indoor exposure is developed. There are guidance documents for indoor contaminants such as
- fine particulate matter (PM2.5)
Indoor Air Reference Levels (IARLs)
To determine IARLs, Health Canada evaluated assessments developed by internationally recognised health and environmental organisations. Health Canada did not carry out any new risk assessments for the IARLs and chose only the most relevant reference level set by other companies. The IARLs listed below represent concentrations associated with acceptable risk levels after long-term exposure (over several months or years) for each specific VOC as determined by the company that performed the risk assessment. The link to the IARLs on Health Canada’s page can be found on this page under the ‘Links’ tab.
Source & image: ©Health Canada
Subject to change without notice; last update: July14, 2023