The hot and humid conditions are creating “elevated pollution levels” Tuesday across parts of the region.
Environment Canada issued a heat warning for parts of Simcoe County and, in a special air quality statement, noted, “high levels of air pollution have developed.”
The weather agency said the situation has resulted in “increasing ground-level ozone concentrations.”
The affected areas include Innisfil, New Tecumseth, Angus, and parts of Dufferin County.
The poor air quality will last through the evening.
“Individuals may experience symptoms such as increased coughing, throat irritation, headaches or shortness of breath. Children, seniors, and those with cardiovascular or lung disease, such as asthma, are especially at risk,” Environment Canada’s website states.