The wind has shifted to bring in clean air from a region that doesn't have smoke — no easy feat given that there are 208 fires burning in B.C. Earlier this week, the air quality in parts of Metro Vancouver was similar to that of Beijing.
"These have been pretty exceptional conditions this week," said Julie Saxton, an air quality planner with Metro Vancouver, on The Early Edition. "I don't recall seeing concentrations [of pollutants] this high while I've been in Vancouver."
The minimal rain forecasted for the weekend may also help air quality, but Saxton said there would need to be a lot of precipitation to really clear the air.
Air Quality Health Index
The fine particulate matter concentrations have been pretty variable throughout the week and changes depending on how those particles interact with other things in the air.
Metro Vancouver also had some ground-level ozone which was contributing to the air quality advisory.
The main scale Metro Vancouver uses is the Air Quality Health Index to look at the combined effect of all pollutants in the air, including ozone and fine particulate matter.
A score of 1 to 3 is low, 4 to 6 is moderate, and 7 to 10 is high. As late as Thursday afternoon, most of Metro Vancouver was at a 4 to 5 on the scale and other parts of the province were at times higher than 10 this week.
A particulate measurement of about 5 to 10 micrograms per cubic metre is considered normal, while 25 micrograms per cubic metre is the threshold for concern. At its worst, Metro Vancouver was recording more than 100 micrograms per cubic metre of fine particulate matter this week.
Saxton says it's important for people to "self-calibrate" as these are guidelines and some people may have higher-than-normal individual responses to the air pollution, even if they're healthy.
Check Metro Vancouver's Air Map and BCAirQuality.ca to see hourly levels and 24-hour averages of what is actually in the air by area and by pollutant.Suggest a correction