A new rule making non-medical masks or face coverings mandatory on the TTC takes effect today.

The policy was adopted by the TTC board last month as part of the city's effort to limit the spread of COVID-19.

The public transit agency says the new rule is necessary, as physical distancing simply will not be possible on many routes as more workplaces reopen throughout Toronto.

Children under two years old and those with certain medical conditions that prevent them from being able to safely wear a mask are exempted, as well as TTC employees who work behind a physical shield or in isolated areas.

The TTC says it will rely on an education campaign rather than enforcement to ensure riders know about the new rule. However "compliance rates" will be measured to determine whether stricter enforcement is required.

"Safety is always our top priority and throughout the ongoing COVID-19 pandemic, we have continually adapted our operations and services based on best practices and in consultation with Toronto Public Health," TTC CEO Rick Leary said in a news release this week.

The transit agency is also beginning an initiative to hand out some one million single-use, non-medical masks to riders who may not otherwise have access to a face coverings. The TTC is working with the city's poverty reduction office to try to ensure that masks are available to anyone who may need to use the network.

Any leftover masks will be diverted to the Wheel-Trans service, and distributed in subway stations and along busy bus routes, the TTC says.

Also starting today, riders will be able to board at any door on TTC buses, and fareboxes will be made available for use once again.

The TTC's new mask policy comes ahead of a city-wide by-law that will require the use of masks in all indoor public spaces, which is set to kick in July 7.