Toronto businesses should have to come clean about their pollution, according to Toronto Public Health.

A new report says 80 per cent of air toxins in the city are caused by small businesses, and the department is recommending city hall pass a bylaw forcing companies to reveal exactly what they're emitting.

"With disclosure ... individual businesses become aware of the kinds of toxic chemicals that they're using on the premises and are emitting into the community," said Monica Campbell, a spokesperson for Toronto Public Health.

"It's very, very helpful -- it's that concept of what you measure, you manage."

The report says 11,000 Toronto businesses contribute a significant amount of cancer-causing chemicals. These air pollutants, such as chromium, mercury and lead, can also cause breathing problems.

It identifies a total of 25 toxic chemicals stores, such as drycleaners and auto body shops, produce.

If city council accepts the plan, Toronto could become North America's first major city to tell people what pollutants they're exposed to -- and where they come from, the Toronto Star reported.

Large industries nation-wide have to report about 330 chemicals to the federal government's National Pollutants Release Inventory.

Their emissions have dropped by more than one-third since the system began 15 years ago, but that accounts for about only 3 per cent of Toronto's sources, according to the Star.

Campbell said companies need to have regulations and co-operate with government to have the tools to help clear up Toronto's dirty air.

"Business needs to be brought alongside -- we want to collaborate with them," Campbell said.

"It's important to not only tell them about reporting requirements, but to also give them the necessary technical resources and information so that they can actually take steps to improve their activities."

Toronto Public Health will present its findings to the city's board of health on Monday.

If the measures are approved, they won't come into effect until next spring, so the city can have more time to consult with local businesses.

With a report from CTV's Desmond Brown