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10 ways to reduce COVID-19 exposure with better ventilation

10 ways to reduce COVID-19 exposure with better ventilation

Ensuring effective ventilation in your workplace is an important way to help control the spread of COVID-19, says Sara Lovell, a WSPS occupational hygiene consultant. But it's sometimes overlooked. "We know that COVID-19 is an airborne, transmissible virus," she explains, "so better air quality and air flow can reduce the risk of the virus spreading in the workplace."

Sara recommends adding improved ventilation to your arsenal of COVID-19 control measures to better protect your workplace and to ensure you are meeting your legal requirements. "Employers are required under the Occupational Health & Safety Act to do everything reasonable to protect workers. I think improved ventilation is a reasonable control."

If you're worried about incurring capital costs, don't be. "This doesn't always have to be an expensive undertaking, and it can make a world of difference," says Sara.

Here are 10 easy and inexpensive options for improving air quality in your workplace, based on guidelines from the U.S. Centers for Disease Control and Prevention (CDC) and Public Health Ontario, with comments from Sara.

Consult with your certified HVAC contractor on implementing the first six HVAC modifications. If you are a tenant, contact your landlord with the same requests.

  1. Upgrade filters. To be effective, HVAC filters need to be able to remove small airborne particles (in the range of 0.1-1 um). Sara suggests switching to a HEPA (high efficiency particulate air) filter if your system can handle it, or to a filter with a high MERV (minimum efficiency reporting values) rating.
  2. Bring in more fresh air. To effectively dilute coronavirus particles, Public Health Ontario recommends ventilating with outdoor air as much as practically possible to minimize or avoid recirculating the air.* One caveat: "If your building is in an area with high levels of smog, ask your contractor whether filters need to be changed more often."
  3. Ensure a steady, even air flow. Bringing in fresh air and extending the time that your fans are running will help to provide a steady source of fresh, clean air into your workplace.
  4. Run the HVAC system longer. Operate it at maximum outside airflow for two hours before and after the building is occupied to increase the number of air changes. "If possible, run it 24/7 to maximize the amount of fresh air coming into your facility," says Sara.
  5. Do a walk-through with your HVAC contractor. Identify rooms or areas with stagnant airflow. Should there be a supply air vent and a return air grate in the room? Have employees blocked off the supply air ducts due to a draft? Ensure the HVAC system is operating as it was designed.
  6. Turn off demand-controlled ventilation (DCV). These controls reduce air supply based on occupancy or temperature during occupied hours, which is something you don't want.

Additional steps to improve ventilation

  1. Open windows and doors. In areas not serviced by an effective HVAC system, this is an easy way to increase fresh outdoor air when weather permits, but make sure it doesn't result in a safety or health risk (e.g., risk of falling).
  2. Use fans to bolster effectiveness of open windows. Place fans so that contaminated air does not flow from one worker to another. "Also make sure they don't disrupt the ventilation controls in welding cells or other types of equipment," says Sara. Use a window fan to exhaust room air to the outdoors and draw in fresh air through other open windows.
  3. Reduce the number of workers in areas where outdoor ventilation cannot be increased.
  4. Ensure restroom exhaust fans are functional and operating at full capacity when the building is occupied.

"When used in conjunction with physical distancing, good personal hygiene, mask wearing, sanitizing and other control measures in your COVID-19 safety plan, better filtration and cleaner air can help reduce the potential for airborne transmission," concludes Sara.

How WSPS can help

Use this Ventilation Checklist (COVID-19) from the Occupational Health Clinics for Ontario Workers (OHCOW) as a guide.

Read about how to fulfil your obligations as an employer in 8 ways for employers to take every reasonable precaution during a pandemic (article)


Focus on Heating, Ventilation and Air Conditioning (HVAC) Systems in Buildings and COVID-19

, Public Health Ontario,


The information in this article is accurate as of its publication date.