VANCOUVER -- While smoky skies remained in Metro Vancouver Thursday, Environment Canada says there was “another slight improvement” in air quality overnight

Meteorologist Matt MacDonald tweeted Thursday morning that the improvement was from a weak onshore flow Thursday. 

A special air quality statement is still in effect for the region, with Environment Canada noting the conditions are causing poor air quality and reducing visibility. 

“A weather system forecast for Friday is expected to bring further improvements this weekend,” the statement says.

A website that uses measurements from the air quality health index listed Vancouver as having the second worst air quality in the world behind Portland, Ore. Thursday morning.

It’s now been 10 days since wildfire smoke from fires burning on the west coast of the U.S. starting affecting conditions in Metro Vancouver.

Environment Canada says people with underlying health conditions should continue to avoid physical activity until the advisory is lifted, especially if breathing feels uncomfortable.