An air quality advisory has been issued again for Metro Vancouver and the Fraser Valley as residents in the region woke up to smoky and hazy skies.
The advisory has been issued for the region because of high concentrations of fine particulate matter due to wildfire smoke burning throughout the Pacific Northwest.
Metro Vancouver says on Saturday, clean marine air swept through the region resulting in a clearing of the smoke from last week.
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However, as it transitioned to the next weather pattern, the winds changed to a northwest flow and by late evening on Sunday, smoke was measured throughout the region.
Elevated levels of fine particulate matter are expected to persist until there is a change in fire and/or weather conditions.
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.
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.
Many people have been posting photos to social media of the hazy conditions on Monday.