The procedural mask (disposable and often blue) is the safest mask to use, especially when spending 15 minutes or more with someone or when in crowded places, like on buses or the metro. However, if you opt to use a reusable mask, the Public Health Agency of Canada is now recommending that you choose a cloth mask that has three layers of materials, including a filter. This new recommendation is based on the latest research about droplets and aerosols.

More info: https://www.rcinet.ca/en/2020/11/03/canadian-health-authorities-now-urge-using-3-layer-masks/