TORONTO -- Wearing a face mask is required in most indoor settings across the country, but some experts are advising Canadians to also wear masks when outdoors.

While the risk of transmission is lower outside than indoors, infectious disease specialist Dr. Isaac Bogoch told CTV News Channel on Monday that masks should still be worn if physical distancing cannot be maintained.

"The risk of transmission is negligible. Of course, nothing is 100 or zero per cent in medicine or life but… it doesn't matter. If you're indoors or outdoors, and you can't maintain a two metre separation, you should be wearing a mask," Bogoch said.

Masks are mandatory in indoor public spaces, including businesses and retailers, in most provinces, but the same measure hasn’t been implemented for outdoors.

Bogoch said masks are only necessary outdoors when the area is crowded and keeping a safe distance from others isn’t possible. But if one was alone outside, for example, Bogoch said he sees no need for a face covering.

"If you're walking through the park outside and you're not near anybody, there's no reason to put on a mask," he said.

Bogoch said he has seen more Canadians wearing masks while outside and recommends people use "common sense" when deciding if they need one.

"Masked indoors for sure, masks outside if you can't maintain two metres of distance, but if you're outside and you're separated from other people by two metres, a mask isn't going to do much there," he said.

However, Bogoch added those who choose to wear a face mask while outside, despite being an appropriate distance from others, should not be shamed for their choice.

"If people want to wear it, there's no shaming and no blaming. People who want to wear masks please do, obviously it's certainly a good thing," he said.

Anna Banerji, director of Global and Indigenous Health at the University of Toronto's Temerty Faculty of Medicine, suggests that Canadians have a mask in their pocket "just in case" when heading outdoors.

Banerji explained in an email to on Monday that certain areas may become unexpectedly busy, and in those situations, she says Canadians may want a face covering if physical distancing is no longer possible.

"The risks for outdoor transmission are generally low, but it depends on context. If you are sitting with the same person for a while the risks increase, versus passing someone by on the street," Banerji said.

McGill University Health Centre emergency physician Dr. Mitch Shulman told CTV Montreal that exhaled virus droplets behave differently in cold weather compared to warm climates. As a result, he says the risk of COVID-19 transmission during winter is greater than at any other time of year.

"Winter is a particularly dangerous time. The virus likes cold, dry weather and so if you’re outdoors, not maintaining proper distancing, (or) wearing a mask, you are actually at more risk than you might otherwise have been," Shulman said.

Infectious diseases specialist Dr. Earl Rubin explained to CTV Montreal that virus droplets exiting one's nose or mouth hang in the air longer in cold weather, increasing the risk of transmission.

Because of this, Rubin said Canadians need to continue doing everything they can to protect themselves from the novel coronavirus, including physical distancing and wearing a mask both indoors and outdoors.

"I'll never say don't wear a mask. We don't have very much in our tool kit to protect ourselves besides distancing, appropriate masking and good handwashing," Rubin said, adding that following these public health measures is prudent regardless of the weather.

Ottawa's medical officer of health Dr. Vera Etches told CTV Ottawa that Canadians should wear face coverings as often as possible when outside one's home.

She stressed last week that Canadians should be staying home amid recent spikes in COVID-19 cases except for essential reasons such as going outdoors for work, errands or physical activity.

In addition to wearing a mask while outside, Etches recommends Canadians choose times and places outdoors that won’t be overly crowded.

"That will just decrease your risk of coming into contact with COVID," Etches said. She added that those who are able wear a mask while exercising outdoors should "absolutely" do so.

With files from CTV Ottawa and CTV Montreal