The Public Health Agency of Canada has developed a guide to inform Canadians about how indoor ventilation, in combination with other recommended public health measures, can reduce the spread of COVID-19 . The guide provides practical tips on how to improve indoor air, ventilation and filtration to help reduce the spread of COVID-19. While this guidance is intended to be used generally across indoor environments, its application will depend on occupancy, the type of building, and the type of activity undertaken in the indoor setting .
According to the guide, the virus causing COVID-19 is known to spread through droplets and aerosols, which represent a risk particularly to people who are in enclosed spaces and indoor situations where people are in close proximity . In addition to preventive measures such as minimizing the number of persons in a place at the same time, maintaining a physical distance of at least 2 metres, using well-constructed, well-fitting masks, and practicing good hand and respiratory hygiene, adequate ventilation can contribute to reducing the risk of COVID-19 transmission in indoor settings .
The guide recommends the following actions to help protect you and others from COVID-19 infection in indoor settings :
– Limit indoor gatherings
– Open windows and doors
– Ventilation systems in non-residential settings (like office buildings) may recirculate air through the HVAC system. In this case, some of the indoor air is diluted with outdoor air and filtered before returning to the occupied space .