Air Canada says face masks with exhalation valves will not be considered as acceptable face coverings on the airline.

The carrier issued an advisory this week indicating that masks with exhalation valves have been deemed ineffective in protecting against COVID-19 by Transport Canada.

Health Canada says non-medical face masks or coverings must allow for easy breathing, fit securely with ties or ear loops, maintain their shape after washing and drying, and be changed as soon as possible if damp or dirty.

They should also be comfortable and not require frequent adjustment and be made of at least two layers of tightly-woven material fabric.

They should not be shared with others, impair vision, or be placed on children under the age of two.