Environment Canada has issued a special air quality statement for Metro Vancouver, showing a very high risk to health due to wildfire smoke from Washington and Oregon.

The agency advised people with underlying medical conditions or serious infections such as COVID-19 to postpone or reduce activities outside.

It said people with heart and lung conditions are most affected by air pollution and the very high risk is expected to continue through at least Sunday in Metro Vancouver and elsewhere in British Columbia.

However, smoke concentrations may vary widely across the Metro Vancouver area and the Fraser Valley Regional District as winds, temperatures and wildfire behaviour change, it said.

The air quality health index ranks risk from low to high on a scale of one to 10, but the current risk goes beyond that level and is listed as 10-plus.

Environment Canada meteorologist Armel Castellan said children, the elderly and pregnant women should avoid spending too much time outdoors to protect their health.

• Murky skies, poor air quality in B.C. as more smoke from U.S. wildfires drifts north

"As for the general population, otherwise healthy adults, we're actually recommending they reduce or actually straight up reschedule strenuous activities outdoors," Castellan said, adding that's particularly the case for anyone experiencing a cough or throat irritation.