More than 230 scientists recently called on health authorities, including the World Health Organization (WHO), to recognize the potential for airborne spread of COVID-19.
Their letter, published in the journal Clinical Infectious Diseases on July 6, 2020, explains, “Studies by the signatories and other scientists have demonstrated beyond any reasonable doubt that viruses are released during exhalation, talking, and coughing in microdroplets small enough to remain aloft in air and pose a risk of exposure at distances beyond 1 to 2 m from an infected individual.”
Three days later WHO responded grudgingly, “Some outbreak reports related to indoor crowded spaces have suggested the possibility of aerosol transmission, combined with droplet transmission.”
Regardless, the weight of evidence and the precautionary principle dictates more prudent action is required in indoor spaces, including workplaces to prevent the transmission of this dreaded disease.
Enhanced ventilation in indoor workplaces
Such is the context for a recent webinar conducted by the Workers Health & Safety Centre (WHSC) on the role for enhanced ventilation
in indoor workplaces confronting COVID-19. Be sure to view the above recording. There we take you through what we mean by enhanced ventilation. Strategies to introduce fresh air, exchange rates, proper filters and other air purifying technologies are among concerns covered.
You may also want to download and share the fact sheet upon which we based the webinar, COVID-19: Enhanced Ventilation.
Also available is the PowerPoint
file for the webinar.
More on the context
Until last week, the WHO and some other health authorities, have focused attention almost exclusively on the spreading of the virus through large respiratory droplets within a one to two metre zone. Further to this, these same health authorities continued to promote what many believe to be a narrow continuum of control measures
including social distancing, hand washing and, most recently, face coverings, as key measures to limit transmission.
While recognizing the appropriateness of all these precautions, the signatories to the above-mentioned letter believe they are “insufficient to provide protection
from virus-carrying respiratory microdroplets released into the air by infected people.”
The letter concludes, “We are concerned that the lack of recognition of the risk of airborne transmission of COVID-19 and the lack of clear recommendations
on the control measures against the airborne virus will have significant consequences: people may think that they are fully protected
by adhering to the current recommendations, but in fact, additional airborne interventions are needed for further reduction of infection risk.” To this end, they suggested a range of measures that should be taken to mitigate airborne transmission, including sufficient and effective ventilation, filtration and air purification technologies.
These scientists are not alone in calling for these preventive actions.
The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE
) has stated, “Transmission of SARS-CoV-2 (the virus that causes COVID-19 disease) through the air is sufficiently likely that airborne exposure to the virus should be controlled. Ventilation and filtration provided by heating, ventilating, and air-conditioning systems can reduce the airborne concentration of SARS-CoV-2 and thus the risk of transmission through the air.”
Many other organizations, including the U.S. Centres for Disease Control and Prevention (CDC
) and Occupational Safety and Health Administration (OSHA
), have also recommended enhanced ventilation and filtration as essential precautionary actions.
And now with their admission of the “possibility” of airborne transmission WHO advises among other things, “avoid crowded places, close-contact settings and confined and enclosed spaces with poor ventilation” and “ensure good environmental ventilation in all closed settings.”
WHSC virtual training & COVID-19 docs
WHSC webinars, our virtual training classrooms and many COVID-19 resources
are made available during these unprecedented and challenging times
to help ensure workers, supervisors, joint health and safety committee members and others have access to a trusted source of training and information. Register today
for any one of a growing list of WHSC virtual training classrooms. Follow us too on social media sites
. There we share important news and insights.
As Ontario’s only designated health and safety training centre
, WHSC supports workers, their representatives, supervisors, contractors and employers in every work sector with comprehensive training programs
and information services
. In all we do, we put workers first. After all, it is their lives and livelihoods that are affected most when workplace hazards, including the COVID-19 virus go uncontrolled.
To learn more: