LETTER: “Ventilation not Ventilators”
November 24, 2020
Hon. Christine Elliott
Deputy Premier of Ontario, Ontario Minister of Health and Long-Term Care
Dr. David Williams, MD, MHSc, FRCPS
Chief Medical Officer of Health, Ministry of Health and Long-Term Care
Dr. Brian Schwartz, MD, MScCh
Vice-President, Public Health Ontario
Dear Hon. Christine Elliott, Dr. David Williams and Dr. Brian Schwartz,
We are a group of Ontario engineers, physicians and professionals who have been following the COVID19 developments closely. We are deeply concerned by the recent increase in cases and hospitalizations in Ontario. We urge you to update the Province’s COVID-19 guidelines, regulations and public communication to reflect the importance of ventilation and to better align with the Public Health Agency of Canada’s recent acknowledgment of aerosol transmission. 1 With winter approaching, our activities are moving indoors and it is therefore imperative that public institutions, workplaces and individuals understand the risk of aerosol transmission as well as the actions that can be taken to combat it.
The rapid global spread of COVID-19 has sparked unprecedented cross-disciplinary research. Contributions from the fields of engineering, aerosol science, medicine and epidemiology are driving a paradigm shift in our understanding of aerosol transmission of respiratory viruses, including COVID-19. With this evolving science, the importance of monitoring and improving ventilation in our communities has become increasingly clear.
The September 28, 2020 report by Canada’s Chief Science Advisor Expert Panel on COVID-19 summarizes high-yield short-term and long-term goals to reduce indoor transmission of COVID-19 and improve indoor air quality. 2 We believe that these recommendations need to be urgently adopted by public health authorities and disseminated to schools, businesses and to the public at large. It is clear from school and corporate pandemic policies and communications that the risk of aerosol transmission is not yet fully integrated. These policies focus on deep-cleaning and two-metre physical distancing, while overlooking ventilation and air filtration.
Current evidence supports the aerosol route as an important mode of transmission of COVID-19 (Appendix A). Virus-laden aerosols can infect susceptible contacts through shared room air, but they are also concentrated at close proximity – like smoke. Control strategies targeting close-proximity transmission, such as physical distancing and mask wearing (for protection of the wearer and source control), are well-established and remain critical to reduce aerosol transmission risk. For transmission in shared room air, however, ventilation and air filtration become even more important, as expelled aerosols from breathing, talking or exercising build up in poorly ventilated spaces. We know that many buildings and residences in our communities have substandard ventilation.
To reflect the current scientific evidence, we call on Ontario’s public health leaders to:
- Update COVID-19 guidance to reflect the risk of aerosol transmission of COVID-19
- Engage engineers and other ventilation specialists to develop clear ventilation standards for indoor institutions and integrate these standards into the reopening guidelines for businesses with a higher risk of aerosol transmission (restaurants, bars and gyms)
- Mandate and fund ventilation assessments and upgrades of essential public institutions such as schools and long-term care homes
- Promote strategies to reduce transmission risk in private homes and businesses through clear public health messaging and education o Promoting indoor mask use even when distanced, routinely opening windows to refresh the air, regular HVAC maintenance and filter replacement, turning on available vented range hoods and bathroom exhaust fans
- Recommend and deploy carbon dioxide (CO2) monitors as a surrogate measure of adequate ventilation o During a TB outbreak, CO2 concentrations above 1000 PPM significantly increased the risk of becoming infected with TB.3 Improving the building ventilation to a CO2 concentration of 600 PPM stopped the outbreak in its tracks.
- Promote portable air filtration (HEPA) units or low-cost homemade devices using MERV-13 filters and box fans
Specific strategies to reduce indoor aerosol transmission of COVID-19 are adeptly summarized in Canada’s Chief Science Advisor Expert Panel on COVID-19 bioaerosol report , the Occupational Safety and Health Administration (OSHA) Alert , and the Harvard TC Chan Risk Reduction Strategies for Reopening Schools Report.
Experts warn that future respiratory viral pandemics are likely. Investing in ventilation and indoor air quality now will save lives and prevent economic hardship in the future. Santé Quebec is actively updating their guidance on ventilation in schools and is rolling out short-term measures in schools across the province. Internationally, Germany is investing €500m to improve ventilation systems in public buildings. The Ontario public health “sanitary reformers” of the late 1800s led the way in overcoming water-borne diseases like cholera and typhoid fever through investments in sewer systems and water treatment plants. 9 We are certain that there were those who thought the task at hand was insurmountable. When the history of Ontario’s response to COVID-19 is written, we hope that our province is once again viewed as a public health innovator.
Signed,
Signed,
Christine Shea, MASc Eng
Environmental Control Systems Engineer
Mississauga
Jennifer McDonald, MD, FRCPC
Physical Medicine and Rehabilitation Physician
Ottawa
Sarah Addleman, MDCM, CCFP-EM
Emergency Physician
Ottawa
Margaret Wolfe-Wylie, MD, FRCPC
Paediatrician
Toronto
Ryan Utter, MA
Ottawa
Carrie Loughry, MBA
Toronto
Supporting Engineers and Scientists:
David Elfstrom, P.Eng, CEM, CMVP
Freelance Energy Engineer, Masks4Canada
Simcoe (Norfolk County)
Conor A. Ruzycki, MSc, PhD Candidate and Killam
Scholar, Aerosol Science, U of A, Masks4Canada
Edmonton
Jose-Luis Jimenez, PhD Aerosol Science
Professor of Chemistry and Fellow of CIRES,
University of Colorado-Boulder, Colorado
Cheryl White, P.Eng
Engineer, Masks4Canada
Toronto
Ilvana Montgomery P.Eng
Electrical Engineer
Toronto
Hugh Montgomery, BASc
Mechanical Engineer
Toronto
Shraddha Pai, PhD Biology, Postdoctoral Fellow
University of Toronto, Masks4Canada
Toronto
Jean-Paul R. Soucy, MSc Epi, PhD Candidate and Vanier
Scholar, Dalla Lana School of Public Health, UofT
Toronto
Daniel Shea, BASc
Electrical Engineer
Richmond Hill
Paul Machuk, P.Eng
Mechanical Engineer
Mississauga
David Markin, BSc Physics,
Physicist
Ottawa
Supporting Physicians:
Kashif Pirzada, MD, CCFP-EM
Emergency Physician, Masks4Canada
Toronto
Edith Hui, MD, CCFP
Family Medicine Physician, Masks4Canada
Toronto
Margaret Wilson, MD, CCFP-EM
Emergency Physician
Ottawa
Shoshanah Deaton, MD, CCFP
Family Physician
Ottawa
Vidya Sreenivasan, MD, FRCPC
Physical Medicine and Rehabilitation Physician
Ottawa
Brie-Anne Rosenberg, MD, CCFP
Family Physician
Ottawa
Lauren Reid, MD, FRCPC
Physical Medicine and Rehabilitation Physician
Ottawa
Jenna Gale, MD, FRCSC
Gynecologist
Ottawa
Rachel Markin, MD, FRCPC
Paediatrician
Toronto
Jennifer Galle, MD, FRCPC
Paediatrician
Toronto
Melanie Ostreicher, MD, FRCPC
Paediatrician
Toronto
Kim Zhou, MD FRCPC
Paediatrician
Toronto
Rae Brager, MD, FRCPC
Allergy and Immunology Physician
Toronto
Katherine Ker, MD, CCFP
Family Physician
Toronto
Shannon Stogryn, MBBS, MSc, FRCSC
General Surgeon
Toronto
Stephanie Siu, MD, FRCPC,
Geriatric Medicine Physician
Toronto
Brian Yau, MD, FRCPC
Anesthesia
Toronto
Julia Sharp, MD, FRCPC
Paediatrician
Toronto
Supporting Professionals and Concerned Citizens:
Michael McDonald, FSA, FCIA
Actuary
Toronto
Jaime Trick, MScPT, BScH, Bed
Physiotherapist
Ottawa
Shael Markin, DDS, MASc
Dentist
Toronto
Meredith Alexander, BSc, BScN, RN
Nurse
Carleton Place, ON
Liza Abraham, RN
Hepatology Nurse
Toronto
Vanessa Chang, MA
Ottawa
Mindy Sichel
Ottawa
APPENDIX A – EVIDENCE FOR AEROSOL SPREAD OF COVID-19
§ We know that 96%, 99% and 94% of particles emitted while coughing, sneezing and speaking,
respectively, are < 100 µm in size10
§ We know that small liquid particles up to 100 µm in size can float in the air for minutes to hours
before settling on surfaces and are thus, by definition, aerosols11
§ We now accept that masks are beneficial for both source control and personal protection12
§ We understand that COVID-19 is an overdispersed pathogen,13-14 not unlike Mycobacterium
tuberculosis (TB),15 which also spreads through aerosols. Both pathogens propagate in clusters and
through superspreading events, where one person infects many others. In the case of COVID-19, 10-
20% of individuals may be responsible for 80% of transmission.16
§ We have seen a clear increased risk of transmission in crowded, poorly ventilated spaces, and from
activities that increase the production of aerosols (speaking, singing, shouting, heavy breathing) 17-18
§ Consistent with the fragile enveloped structure of coronaviruses, fomite transmission is not
considered to be the primary mechanism of spread16,19
§ COVID-19 genetic material has been harvested in ventilation systems20 and ferret studies have
demonstrated COVID-19 infections through the aerosol route21
§ We now recognize that ventilation is an important factor in preventing the spread of COVID-19
indoors22
REFERENCES
1. Government of Canada. Coronavirus disease (COVID-19): Prevention and risks: How Covid-19
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2. Government of Canada. The Role of Bioaerosols and Indoor Ventilation in COVID-19
Transmission. September 28, 2020 http://science.gc.ca/eic/site/063.nsf/eng/h_98176.html
(accessed Nov 15 2020)
3. Du CR, Wang SC, Yu MC et al. Effect of Ventilation Improvement during a Tuberculosis Outbreak
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4. Occupational Safety and Health Administration. OSHA Alert: COVID-19 Guidance on Ventilation
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8. (Oct 19 2020). Coronavirus: Germany improves ventilation to chase away Covid. BBC News.
https://www.bbc.com/news/world-europe-54599593
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https://www.cpha.ca/sewage-and-sanitary-reformers-vs-night-filth-and-disease (accessed Nov
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Occupational Safety and Health. Centers for Disease Control and Prevention.
https://www.cdc.gov/niosh/topics/aerosols/pdfs/Aerosol_101.pdf (accessed Nov 15 2020)
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https://www.canada.ca/en/public-health/services/diseases/2019-novel-coronavirusinfection/prevention-risks/about-non-medical-masks-face-coverings.html (accessed Nov 15
2020)
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in two Indian states. Science. 2020 Nov 6;370(6517):691-697. doi: 10.1126/science.abd7672.
Epub 2020 Sep 30. PMID: 33154136.
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reveals hidden super-spreading events during the early outbreak phase. Nat Commun 11, 5006
(2020). https://doi.org/10.1038/s41467-020-18836-4
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in Mycobacterium tuberculosis transmission: evidence from contact tracing. BMC Infect
Dis 19, 244 (2019). https://doi.org/10.1186/s12879-019-3870-1
16. Fang, F., Benson, C., del Rio, C., et al. COVID-19 – Lessons Learned and Questions Remaining.
Clinical Infectious Diseases. 26 October 2020. https://academic.oup.com/cid/advancearticle/doi/10.1093/cid/ciaa1654/5940148
17. Government of Canada. Coronavirus disease (COVID-19): risks of getting COVID-19. 2020-11-03
https://www.canada.ca/en/public-health/services/diseases/2019-novel-coronavirusinfection/prevention-risks.html#r (accessed Nov 15 2020)
18. WHO. Coronavirus disease (COVID-19): How is it transmitted? 20 October 2020.
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2020)
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https://www.cdc.gov/coronavirus/2019-ncov/faq.html (accessed Nov 15 2020)
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COVID-19 wards. Sci Rep 10, 19589 (2020). https://doi.org/10.1038/s41598-020-76442-2
21. Kutter J, de Meulder D, Bestebroer T, et al. SARS-CoV and SARS-CoV-2 are transmitted through the
air between ferrets over more than one meter distance. BioRxiv. October 19 2020.
https://doi.org/10.1101/2020.10.19.345363
22. WHO. Coronavirus disease (COVID-19): Ventilation and air conditioning in public spaces and
buildings. 29 July 2020. https://www.who.int/news-room/q-a-detail/coronavirus-disease-covid19-ventilation-and-air-conditioning-in-public-spaces-and-buildings (accessed Nov 15 2020)