Metro Vancouver expands air quality advisory, warns of fine particulate and ground-level ozone

Vancouver -

It’s hard not to notice Metro Vancouver’s hazy horizon. Blue skies have been replaced with a brown fog. It’s something the region has experienced during previous summers, but this year, officials say the haze is being caused by something different.

Portions of the region are under an air quality advisory, first put in place on Saturday for eastern Metro Vancouver and the central Fraser Valley Regional District. But on Tuesday afternoon, the Metro Vancouver authority said the advisory would be expanding.

“The Air Quality Advisory for ground-level ozone is being expanded to include the eastern Fraser Valley Regional District,” reads a statement from Metro Vancouver.

The authority says there’s also an elevated concentration of fine particulate matter in the air, also called PM2.5, which is expected to persist until there is a change in the weather.

“Right now, we’re stuck in a non-movement pattern,” says Armel Castellan, a meteorologist with Environment and Climate Change Canada. In other words, the region is experiencing a high-pressure weather system that allows heat to build up.

“What else builds up? Pollutants. Any kind of car or building exhaust,” explains Castellan. “Those things are building up over time and we can see that haze of smog when we look horizontally.”

In previous summers, views across the Lower Mainland have been obscured by wildfire smoke creeping in from B.C.’s interior, Washington, or as far south as California. So far, fires have not impacted air quality.

While the air closer to land appears to be much clearer than the smoggy skies, experts say it still poses a risk. An air quality advisory remains in place for eastern Metro Vancouver and the Central Fraser Valley Regional District, due to an increase of ground-level ozone.

Ground-level ozone forms as nitrogen oxides and volatile organic compounds react in the heat. Nitrogen oxides include the pollutants emitted when oil and gas is burned, while volatile organic compounds include the particles emitted from solvents.

Fine particulate matter or PM2.5, refers to airborne solid or liquid droplets with a diameter of 2.5 micrometres or less. PM2.5 can easily penetrate indoors because of its small size.

For people with chronic illnesses, children, the elderly and pregnant people, prolonged exposure to ground-level ozone may cause coughing, chest discomfort, or shortness of breath.

“We typically see higher concentrations of ground-level ozone in the afternoon,” says Kyle Howe, an air quality analyst with Metro Vancouver. “We really encourage people over those times to take it easy and not do overly strenuous activities.” Exposure is particularly concerning for people with lung or heart disease, chronic obstructive pulmonary disease (COPD), asthma, diabetes, outdoor workers, and those who are unhoused.

“We advise people to seek out air-conditioned spaces and make sure they’re staying hydrated,” says Howe.

He adds the haze will eventually dissipate as the weather cools down, and could begin thinning out as early as Wednesday. As for whether blue skies will give way to smog again this summer, Howe says it’s difficult to predict.