Blog Post #1438 – Improving Indoor Air Quality – Part 3

Article from the OH&S Canada magazine – (Fall – 2022)

Written by the Canadian Centre for Occupational Health and Safety (CCOHS)

“Increase the Introductions of Outdoor Air”

Natural ventilation can be maximized in order to improve indoor air quality. Open outdoor air dampers beyond minimum settings to reduce or eliminate HVAC air circulation.

In mild weather, this will not affect thermal comfort or humidity. However, this may be difficult to do in cold, hot or humid weather, and may require consultation with an experienced HVAC professional.

Open windows and doors to allow outside air in, as weather permits and if it’s safe to do so. Allowing outside air in, even for a few minutes at a time throughout the day, can improve ventilation with minimal impact on indoor temperature and humidity. If outside air is of low quality – due to pollen for instance – it may be necessary to minimize its intake or pre-filter the air as it enters the building.

Another approach is to optimize air flow patterns to improve ventilation effectiveness. This improvement can reduce contaminants more efficiently without needing to increase the number of air changes per hour. To do this safely, carefully consider fan placement based on the room’s configuration. Avoid placing fans in a way that could potentially cause contaminated air to flow directly from one person to another. One helpful strategy is to use a window fan, placed safely and securely in a window, to exhaust room air to the outdoors. This will help draw air into the room via other openings and doors without generating strong room air currents. Similar results can be established in larger facilities using other fan systems, such as gable fans and roof ventilators.

Part #4 of 4 should be delivered over the next few days.

HRS Group Inc. has a great team that can help you with all your health and safety needs. Contact Deborah toll free at 1-877-907-7744 or locally at 705-749-1259.

We can also be reached at 

Ensure your workplace is a safe place.

Remember – In Canada, “ALL Accidents are Preventable”

‘Work’ and ‘Play’ safe.

Daniel L. Beal

CHSEP – Advanced Level
CEO & Senior Trainer
HRS Group Inc.


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