Environment Canada warned the air quality in Toronto is deteriorating on Wednesday and urged people to avoid strenuous outdoor activity until it improves.

A special air quality statement was issued at 11:30 a.m.

Environment Canada said the hot and sunny weather is increasing the concentrations of ground-level ozone, which could cause coughing, throat irritation, headaches or shortness of breath.

Children, seniors and people with lung conditions will be hit hardest by the poor air quality, the agency said.

The poor air is expected to be at its worst this afternoon.