Residential Indoor Air Quality Guidelines

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Summary of guidelines

The Residential Indoor Air Quality Guidelines summarize the health risks of specific indoor pollutants. They also provide information on:

  • known health effects of indoor air contaminants
  • indoor sources of air contaminants
  • recommended exposure limits
  • recommendations to reduce your exposure to pollutants

In some cases an exposure limit cannot be determined from the available scientific evidence. When this happens, a guidance document is developed that focuses on actions to reduce indoor exposure.

Summary of recommended exposure limits

The guidelines recommend exposure limits for contaminants that affect indoor air quality. These limits 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

The following guidelines or guidance have been developed for various contaminants. The recommended sampling time that this guideline is based on is shown in brackets:

  • benzene
    • keep indoor levels of benzene as low as possible
  • 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)
  • fine particulate matter (PM2.5)
    • keep indoor levels of PM2.5 as low as possible
    • use a stovetop fan (which exhausts outdoors) while cooking and do not allow smoking indoors
  • mould
    • address any water damage in residences within 48 hours to prevent mould growth; and,
    • address any visible or concealed mould growing in residential buildings
  • 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)

New guidelines are posted as more contaminants are assessed.

Contact the Air Health Science Division office if you:

  • have questions about the Residential Indoor Air Quality Guidelines
  • would like to read the scientific assessments used to develop the guidelines
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