A new air quality advisory has been issued for eastern parts of Metro Vancouver and the Fraser Valley.
Metro Vancouver issued the advisory on Wednesday due to high concentrations of ground-level ozone, which are expected to stick around until there’s a change in the weather.
The advisory applies to Coquitlam, Port Coquitlam, Surrey, Langley, Maple Ridge, Pitt Meadows and the communities of the Fraser Valley.
A similar advisory was put into place during the region’s last hot spell at the end of July.
Ground-level ozone is a product of pollution from fuel combustion or solvents reacting with air in the presence of sunlight.
Higher concentrations are usually found mid-afternoon and in the evening on summer days.
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Exposure to ground-level ozone can be particularly harmful to infants and the elderly, along with people who have health problems such as asthma or heart and lung disease.
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The region is advising people to avoid strenuous activity later in the day. It also says anyone who shows symptoms such as coughing, wheezing, shortness of breath or chest discomfort should seek medical advice.
The advisory is not related to visible haze in the region, which is being produced by wildfires in the B.C. interior and western U.S. states.
Metro Vancouver says concentrations of fine particulate matter, which is produced by the fires, are not high enough to be of concern.