Metro Vancouver says ground-level ozone concentrations are expected to remain high for several days.

The Metro Vancouver Regional District issued an air quality advisory for eastern parts of the region, along with the Fraser Valley.

The regional district says ground-level ozone concentrations are the concern — not the haze of wildfire smoke from the Nohomin Creek fire near Lytton.

“We’re advising people to kind of take it easy,” said Kyle Howe, air quality analyst with Metro Vancouver. “Especially those with underlying, chronic conditions — go inside, find a cool spot with air conditioning if you can. Make sure you’re drinking fluids and just make sure you’re monitoring yourself during this.”

Ozone is a good thing when it’s high in the atmosphere, blocking harmful UV rays, but according to Howe, ground-level ozone can be harmful.

It can cause difficulty breathing, and irritate the eyes, nose and throat, according to Health Canada. People with underlying conditions are more sensitive to ozone. 

Howe said ozone is not emitted directly into the air, but rather results from a chemical reaction between nitrogen dioxides, which come from things like combustion emissions, volatile organic compounds, which come from things like solvents and fuels, and sunlight.”This is something that can affect everyone,” said Howe, who recommends people shift their more strenuous, outdoor activities like exercising to the morning, when ozone concentrations are lower. Concentrations increase in the afternoon and evenings.

He said anyone who wants to help reduce their impact and improve the air quality can reduce their driving and refueling vehicles, and consider retrofitting their homes to be more efficient.

Environment Canada is forecasting hot temperatures throughout the week and possibly into the weekend, meaning the conditions to produce plenty of ground-level ozone will continue for several days, said Howe.