Indoor air quality resources for professionals

Learn more about guidelines for indoor air quality and exposure limits for indoor air contaminants.

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Guidelines and guidance for indoor air contaminants

We publish documents that summarize the health risks of specific contaminants in indoor air and provide information on:

  • sources of indoor air contaminants
  • recommendations to reduce exposure to indoor air contaminants

These documents include:

  • residential indoor air quality guidelines
  • guidance documents

Residential indoor air quality guidelines

The Residential Indoor Air Quality Guidelines present recommended exposure limits (also called guideline values) for contaminants. The exposure limits represent the concentration of indoor air contaminants below which health effects are unlikely to occur. The guidelines include:

  • long-term exposure limits
    • for health problems that can occur from continuous or repeated exposure over several months or years
  • short-term exposure limits
    • for health problems that can occur immediately after a brief exposure

We have developed guidelines for specific indoor air contaminants. This list shows the recommended exposure limit for the sampling time (in brackets):

  • acetaldehyde
    • long-term exposure limit (24 hours): 280 µg/m3 (157 ppb)
    • short-term exposure limit (1 hour): 1420 µg/m3 (795 ppb)
  • acrolein
    • long-term exposure limit (24 hours): 0.44 µg/m3
    • short-term exposure limit (1 hour): 38 µg/m3
  • carbon dioxide
    • long-term exposure limit (24 hours): 1800 mg/m3 (1000 ppm)
  • carbon monoxide
    • long-term exposure limit (24 hours): 11.5 mg/m3 (10 ppm)
    • short-term exposure limit (1 hour): 28.6 mg/m3 (25 ppm)
  • formaldehyde
    • long-term exposure limit (8 hours): 50 µg/m3 (40 ppb)
    • short-term exposure limit (1 hour): 123 µg/m3 (100 ppb)
  • naphthalene
    • long-term exposure limit (24 hours): 10 µg/m3 (1.9 ppb)
  • nitrogen dioxide
    • long-term exposure limit (24 hours): 20 µg/m3 (11 ppb)
    • short-term exposure limit (1 hour): 170 µg/m3 (90 ppb)
  • ozone
    • long-term exposure limit (8 hours): 40 µg/m3 (20 ppb)
  • radon
    • exposure limit 200 Bq/m3
  • toluene
    • long-term exposure limit (24 hours): 2.3 mg/m3 (0.6 ppm)
    • short-term exposure limit (8 hours): 15 mg/m3 (4.0 ppm)

*You can request the science assessments on which these exposure limits are based.

Guidance documents for specific indoor air contaminants

In some cases, we can’t determine an exposure limit from the available scientific evidence. When this happens, we develop a guidance document that focuses on actions to reduce indoor exposure.

For example, we have developed guidance documents for indoor air contaminants, including:

  • mould
  • benzene
  • fine particulate matter (PM2.5)

Indoor air reference levels (IARLS)

We have also identified indoor air reference levels (IARLs) for 25 different volatile organic compounds (VOCs) commonly found in indoor air.

Risk assessment prioritization

We have developed a process to prioritize contaminants for assessment based on their potential to pose a health risk at levels found in Canadian homes. We conduct this prioritization process approximately every 3 years.

Guidance for non-residential (public) indoor spaces

We have developed detailed guidance for use in non-residential indoor environments. These documents provide evidence-based recommendations on maintaining and improving air quality in public indoor spaces. These documents can be used by local jurisdictions, public officials, managers, employees and anyone who has a role to play in indoor air quality. They include:

Contact us for more information.

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