The pulp mills are the likely source of the haze that settled over the Bowl area this morning, according to University of Northern British Columbia professor Peter Jackson.
Jackson noted a light easterly wind and a spike in the reading for particulate matter at the Plaza 400 monitoring station, which jumped from about 17 micrograms per cubic metre at 10 a.m. to 61 at 11 a.m.
"The high levels are most likely from the pulp mill area - a phenomena called 'fumigation' where there is a spike in air pollution levels in mid-late morning when the nocturnal inversion begins to break down and pollution-rich air mixes downward to the surface," he said in an email shortly before noon.
"In a couple of hours the PM2.5 levels should go down again as fresh air mixes with the polluted air."
B.C. Ministry of Environment air quality meteorologist Gail Roth confirmed Jackson's assessment.
"Those types of events are common at this time of year," she said. "That was just a particularly noticeable one because the visibility went down as well. But a lot of that visibility would've been from water vapour, although we did see the spike, like Peter had mentioned, in the PM 2.5."
The haze had lifted by early afternoon and fell short of prompting the ministry to issue an air quality advisory.
