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Ventilation Resources

Ventilation Resources for Workplaces to Prevent Transmission of COVID-19

Emerging research suggests that it is likely that SARS-CoV-2 can be transmitted through the air. Workplaces should control airborne exposure to the virus through changes to ventilation systems to reduce airborne exposures. OHC has prepared a fact sheet, “Indoor Ventilation and Reducing Transmission of COVID-19” on best practices for workplaces.

This list of resources and readings below will further help workplaces to understand and prevent the transmission of COVID-19 by improving indoor air quality.

Air Handling in the Era of Coronavirus

This brief article highlights practical steps you can take to minimize the spread of airborne viral particles. These particles come in a variety of sizes but most of the attention has focused on “large” particles that can fall to the floor OR enter human airways within a radius of 6 feet. Spreading of smaller particles is possible which is why improving indoor air quality is important.

Back-to-Work Ventilation-Related Checklist for Workers and Health and Safety Professionals

Are you in charge of protecting health and safety in your workplace? This handy checklist is for you! Getting back to work and school has been a challenge for everyone, but you can boost your efforts by following this checklist. It’s easy to take your everyday heating, ventilation and air-conditioning (HVAC) systems for granted so it’s important to understand where you can adjust your system to promote cleaner, more ventilated air. This will minimize the inadvertent spread of coronavirus particles (small or large, but especially small-size particles). Take a moment now to review whether your workplace is following best practice guidelines.

Ventilation Checklist from Occupational Health Clinic for Ontario Workers (OHCOW)

Ventilation and filtration provided by HVAC systems can reduce the airborne concentration of SARS-CoV-2 and thus the risk of transmission through the air. This Ventilation Checklist (COVID-19) can be used as a guide to assess the suitability of ventilation in your workspace/building. Available in English and French.

What’s Up with Duct Cleaning?

How often do you think about the vents and ductwork in your house or workplace? Probably not often enough. With the global COVID-19 pandemic in full swing it’s important to take some time to understand what you can do to improve indoor air-quality. In this article, you’ll learn the basics of how to maintain a high level of indoor air quality (IAQ), which is critical to minimizing transmission of SARS-Cov-2 the virus that causes COVID-19.

COVID-19 Guidelines from the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)

ASHRAE is considered the industry leader in North America producing the most current COVID-19 guidelines and best practices to prevent indoor transmission of airborne pathogens such as SARS-CoV-2.

Latest COVID-19 Workplace Guidance from ASHRAE:

Schools & Universities
Guidance for Building Operations During the COVID-19 Pandemic
Other Workplace COVID-19 Guidelines from ASHRAE

**Note that downloading other COVID-19 guidelines for other industries will incur a fee**

American Industrial Hygiene Association (AIHA) Guidance Document “Reducing the Risk of COVID-19 Using Engineering Controls”,

A seven page Guidance Document explains the importance of engineering solutions, such as ventilation to reduce the risk of COVID-19. It provides details on air change rates and high efficiency filtration systems.

Background Reading

COVID-19 and Potential for Airborne Transmission – What You Need to Know

The scientific community remains split on the extent to which SARS-CoV-2, the virus that causes COVID-19, is spread through small-particle aerosol transmission. The World Health Organization (WHO) continues to assert that the novel coronavirus is transmitted primarily through ‘large air droplets’ that project and fall within a radius of 1 – 2 metres (the rationale for maintaining at least 2 metres of social distance at all times).

Emerging evidence suggests that the virus can transmit in smaller particles over greater distances depending on many factors affecting indoor air quality. Provided below is a selection of research papers, news articles and industry guidelines for workers, health and safety committees, health and safety professionals, and workplaces who wish to stay informed on this topic.

Current Peer-Reviewed Research Articles

Below are links to current evidence-based literature on the topic of COVID-19, the aerosol transmission of SARS-CoV-2 and indoor ventilation best-practices.

It is Time to Address Airborne Transmission of COVID-19, L. Morawska & D. Milton, Oxford University Press

Two metres or one: what is the evidence for physical distancing in COVID-19?, BMJ (Aug, 2020)

A Rosetta Stone for Understanding Infectious Drops and Aerosols, D. Milton (July, 2020) Journal of the Pediatric Infectious Diseases Society

Recognition of aerosol transmission of infectious agents: a commentary R. Tellier et al (June, 2020)

Airborne Transmission of SARS-CoV-2: A Virtual Workshop, The National Academies of Sciences Engineering Medicine (Aug, 2020)

Reducing transmission of SARS-CoV-2, K. Prather et al, Science (June, 2020)

Current News Articles

These are recent and highly referenced, highly discussed news articles that discuss the potential aerosol transmission of SARS-Cov-2.

“We Need to Talk About Ventilation” The Atlantic Monthly (July, 2020)

This is the safest indoor space to prevent the spread of COVID-19, according to a mechanical engineer” Fast Company (Aug, 2020)

How ‘Superspreading’ Events Drive Most COVID-19 Spread, C. Ashwanden (June, 2020)

Could a Janky, Jury-Rigged Air Purifier Help Fight Covid-19?, A. Rogers, Wired Magazine (Aug, 2020)

OHC’s Webinar: Protecting workers in the pandemic: What needs to be done about airborne transmission and why?

Members of the Canadian Aerosol Transmission Coalition talked about their activities, recommendations and accomplishments designed to truly protect workers in the current pandemic. Members come from a variety of backgrounds, bringing with them skills and experiences related to occupational health principles and practices, microbiology and infectious diseases, medicine, ventilation, respirators, cleaning/disinfecting products and using the law.

Review their presentation here:

Marianne Levitsky, Senior Occupational Hygiene Associate

Laurence Svirchev, Occupational Hygienist

Stéphane Bilodeau, Ventilation Engineer

Simon Smith, Retired Senior Specialist in respiratory protection

Dorothy Wigmore, Occupational Health Specialist

Resource and Chat session

Recorded Webinar

Thank you to Dorothy Wigmore, Occupational Hygienist at for sharing many of the above documents and resources.