- Update COVID-19 guidance to address the risk of aerosol transmission of COVID-19
- Promote strategies to reduce transmission risk in private homes and businesses through clear public health messaging and education
- Avoid the “3 C’s” through indoor mask wearing 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
- Mandate and fund ventilation assessments and upgrades of essential public institutions such as schools and long-term care homes
- Ensure that no high-risk health care worker or other essential worker is denied access to a fit-tested respirator (N95, elastomeric or equivalent)
- Risk assessment by health care workers should go beyond the presence of “aerosol generating procedures” and should take into consideration aerosol-generating behaviours (e.g., shouting, singing, coughing, sneezing, heavy breathing), proximity to the patient, time spent with the patient, building air quality, and patient compliance with masking for source control
- Risk assessment for other essential workers should consider crowding, close contact, presence of aerosol-generating behaviours, and building air quality
- Recommend and deploy carbon dioxide (CO2) monitors as a surrogate measure in case of inadequate ventilation to reduce long-range transmission risk in shared room air
- During a TB outbreak, CO2 concentrations above 1000 PPM significantly increased the risk of becoming infected with TB [9]. Improving the building ventilation to a CO2 concentration of 600 PPM stopped the outbreak in its tracks.
- Include appropriately sized portable air filtration (HEPA) units or low-cost homemade devices using MERV-11/13 filters and box fans as options for filtering out bioaerosols indoors when ventilation is suboptimal
- 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 (e.g., restaurants, bars and gyms)
- Specific strategies to reduce indoor aerosol transmission of COVID-19 are adeptly summarized in the Chief Science Advisor of Canada’s COVID-19 Expert Panel’s bioaerosol report [7], the Occupational Safety and Health Administration (OSHA) Alert [10], the Harvard TC Chan Risk Reduction Strategies for Reopening Schools Report [11], the CDC’s “COVID-19 Ventilation in Buildings” guidance [12], the European CDC’s “Heating, Ventilation and Air-Conditioning Systems in the Context of COVID-19: First Update” [13], and the “ASHRAE Position Document on Infectious Aerosols” [14].
from “Time for government to take aerosol transmission of COVID-19 seriously.”