Environment Canada has issued a special air quality statement for much of southern Ontario, including Windsor-Essex.
It advises of the potential for deteriorating air quality because of the hot, sunny conditions which could increase ground level ozone concentrations this afternoon.
Short-term high risk humidex values for a couple of hours are possible where the public may experience coughing, throat irritation, headaches or shortness of breath.
Children, seniors, and those with cardiovascular or lung disease, such as asthma, are especially at risk and the national weather service advises to limit strenuous outdoor activities until the statement is lifted.
Exposure to air pollution is particularly a health concern for people with heart or breathing problems, those with diabetes, children and the elderly.