In most cases, a medical-grade mask provides necessary protection. N95 masks are reserved for specific patient care situations. There are protocols in place for the use of N95 masks under the PPE allocation framework
(PDF) for the specific settings in which they are required.
Evidence from over 50 million cases worldwide suggests that COVID-19 is primarily spread by droplet and contact transmission. Liquid droplets come out of the mouth and nose when a person coughs, sneezes, and talks or sings. These droplets will quickly fall to the ground within 1-2 metres, but they can land on another person if they are within that range. COVID-19 can spread if droplets containing the virus enter another person’s body through the eyes, nose or throat or through contact if a person touches an infected surface and then touches their mouth, nose or eyes.
There is some evidence demonstrating that COVID-19 can occasionally be spread via the aerosol (or airborne) route in specific circumstances. Aerosols are generally smaller than droplets, and can linger in the air for longer. This means that there are rare situations where aerosols containing COVID-19 may occur and infect individuals (e.g. small spaces with many people and poor ventilation, such as fitness classes). This is not known to have occurred in health care settings, though an exception is aerosols produced by aerosol-generating medical procedures (AGMPs). With the exception of AGMPs, N95 masks are generally not required to protect from COVID-19.
We appreciate that the issue of COVID-19 being spread via aerosols has caused some concern. So far, the evidence continues to show that COVID-19 is spread primarily by droplets, with clear protection provided by physical distancing, mask use, and hand hygiene. These measures, once instituted in a widespread manner in B.C. in the spring, worked extremely well in reducing infections. If aerosols played a primary role in COVID-19 spread, the measures that we have been using would not have worked, and we would be seeing widespread outbreaks in areas implementing them, such as health care settings – something that has not been observed.