Several outdoor activities and events scheduled for Thursday in the Greater Toronto Area have been cancelled due to continued poor air quality brought on by smoke from wildfires.

A special air quality statement remains in effect for Toronto as smoke from forest fires in Quebec and northeastern Ontario has resulted in high levels of air pollution.

Environment Canada said poor air quality will persist into the weekend.

As a result, the City of Toronto has cancelled some of its outdoor recreation programs for Thursday.

"Other programs were able to be modified and moved indoors," the city said. "City sport fields, baseball diamonds and parks remain open and available. Toronto Public Health recommends organizers of outdoor sporting events consider air quality when making decisions about holding or modifying events."

The city has also suspended outdoor activities at its Toronto Early Learning & Child Care Centres.

The city added that Toronto History Museums have cancelled all outdoor programming until the special air quality statement is lifted, while St. Lawrence Market is reviewing its outdoor programming.

The Toronto Zoo says it is reducing its operating hours on Thursday and will only be open from 9:30 a.m. to 3 p.m. It is also limiting access to the outdoors for some animals and limiting the amount of time staff and volunteers work outside.

Woodbine Entertainment has announced that both thoroughbred and standardbred racing at Woodbine Racetrack and Woodbine Mohawk Park on Thursday have been cancelled.

"This decision is consistent with the advice Woodbine has received from veterinarians, medical practitioners, and other racing officials, including the Alcohol and Gaming Commission of Ontario (AGCO)," the group said in a statement.

"Woodbine will continue to monitor the situation and weather forecasts to determine whether it will proceed with live racing on Friday, June 9."

Meanwhile, the Toronto District School Board also said that recess will be held indoors.

"We will continue to monitor the Air Quality Health Index and follow advice from Environment Canada and/or Toronto Public Health and provide further updates, as required," the board said in a statement on Wednesday.

"TDSB schools and sites will also continue to ensure that HEPA air filter units are being used where possible."

The board said a decision regarding Friday's outdoor activities will be determined on Thursday.

Several GTA schools made similar moves, adjusting their outdoor activities in response to the deteriorating air quality.