An air quality advisory has been issued for eastern parts of Metro Vancouver along with the Fraser Valley.
Metro Vancouver says the advisory was put in place due to high concentrations of ground-level ozone, which are expected to stay for several days.
The advisory covers the entire Fraser Valley, along with the Metro Vancouver municipalities of Surrey, Langley, Pitt Meadows, Maple Ridge and the Tri-Cities.
The advisory comes with a noticeable haze, now in its second day across the region, however, Metro Vancouver says the two phenomena are not linked.
WATCH: Air quality advisory issued due to Okanagan wildfires
The haze, it says, is due to wildfire smoke coming from the Richmond bog fire, B.C. wildfires, and “distant wildfires burning in Eurasia and Alaska.”
But that smoke is not causing fine particulate matter in the air to exceed safe air quality levels, it said.
READ MORE: Wildfire smoke from as far as Ontario and Siberia affecting B.C. air quality
“Ground-level ozone is not emitted directly into the air,” said a media release from Metro Vancouver.
“It is formed when nitrogen oxides (pollutants emitted when fuels are burned) and volatile organic compounds (emitted from solvents) react in the air in the presence of sunlight. The highest levels of ground-level ozone are generally observed between mid-afternoon and early evening on summer days.”
Metro Vancouver advises that people avoid strenuous outdoor activities during the mid-afternoon and early evening.
READ MORE: Extreme fire danger as smoke from Greece, Siberia reaches the Okanagan
It warns that ozone exposure is particularly problematic for infants, seniors, and people with health issues such as asthma or heart and lung disease.
Anyone who experiences shortness of breath, coughing or wheezing should consult their health care provider, it said.
Last summer, Metro Vancouver was put under an air-quality advisory for nearly two weeks, when it was socked-in by a thick blanket of wildfire smoke from fires in B.C.’s interior.
Air quality advisories are issued by the region in consultation with Environment Canada, the Fraser Valley Regional District and B.C.’s Ministry of Environment.
You can find up-to-date air quality readings at Metro Vancouver’s AirMap.
The advisory comes as most of B.C. finds itself under smoky-sky bulletins driven by smoke from B.C. and international wildfires.
You can find a full map of Environment Canada warnings and advisories for B.C. here.