Face masks are dangerous to the health of some Canadians and problematic for some others, health advocates say.
In recommending people wear masks in public to prevent the spread of COVID-19, national chief public health officer Theresa Tam has also warned against judging those who can't wear them.
"Be very aware of those with different types of cognitive, intellectual disabilities, those who are hearing impaired and others," Tam said.
"Don't assume that someone who isn't wearing a mask or is wearing something different doesn't have an actual reason for it."
Asthma Canada president and CEO Vanessa Foran said simply wearing a mask could create risk of an asthma attack.
She said if a mask inhibits the ability of someone to breathe in any way, it's recommended to not wear one.
Foran suggests asthmatics wear a mask in their homes for 20 minutes to test their comfort level before venturing out, and also to head out in cooler weather.
"Wearing masks means breathing hot and humid air, so that can trigger asthma symptoms," she said.
"We say if they cannot wear a mask, they must ensure they're maintaining physical distancing and practising good hand hygiene."
Foran said people with severe allergies might also find wearing a mask difficult at this time of year.
Dominique Payment, family support representative for Autism Canada, said people on the spectrum have trouble with sensory processing.
They also have tactile, olfactory and nervous-system hypersensitivity that wearing a mask could aggravate.
"It could cause some serious challenges," she said. "Because their senses are so heightened, it affects everything."
Payment has two children on the autism spectrum. One is anxious about masks because he associates them with having his teeth cleaned at the dentist, which he dislikes.
"Unfortunately this whole COVID situation and everyone wearing masks can cause some anxiety for these children because they are associating with not-so-positive experiences."
Payment said having children put a mask on a favourite stuffed animal, or choosing a fabric colour and pattern for a mask, could help prepare them to wear one.
The deaf and hard of hearing can't read lips covered by an opaque mask, which also muffles sound for those with partial hearing.
"Typically hard-of-hearing individuals rely more on lip-reading. Masks are still a challenge for deaf people," said Wissam Constantin, vice-president of governance and membership for the Canadian Association of the Deaf.
"The sign for tired, you can sign for tired, but depending on your mouth movement, it will emphasize how exhausted you are.
"It's not only about lip-reading. It's about facial expression."
Constantin said he laboured to communicate with masked employees at a grocery store this week.
"I just wanted them to lift up the mask to tell me what they were trying to tell me," he said.
"The workers did struggle. Of course, they have their own concerns. It is a really difficult situation," he said.
"That situation is definitely lending to more isolation within the deaf community.
"We really rely on facial expression as a form of communication, so the masks are a barrier in making those connections in the community."
Alaska-based company Rapid Response PPE has developed face masks with clear shields so the deaf and hard of hearing can see facial cues and lip movement.
"That could be useful," Constantin said. "If the ministry of public health thinks they're safe, that would really help if we were able to see mouth movement."
This report by The Canadian Press was first published May 21, 2020
-- With files from The Associated Press.
