An air quality advisory was issued Tuesday morning due to high levels of particulate matter as measured downtown.
"Light winds and dry conditions overnight as well as clear skies contributed to dust accumulating in the air shed," Northern Health and the Ministry of Environment said in a press release issued shortly before 9:30 a.m.
"Air quality is expected to be better at higher elevations. Levels may improve slightly this afternoon but increase again this evening."
Levels of coarse particulate, or PM 10, exceed the provincial air quality objective of 50 micrograms per cubic metre, averaged over 24 hours, at Plaza 400 downtown, where it struck 55.
"Based on the quality data, the high levels are mainly due to road dust in the bowl area," officials said.
The level remained well below 50 at both the BCR industrial site and College Heights.
Levels of fine particulate were also well below the standard of 25 micrograms per cubic metre at the three measuring stations.
The advisory is expected to be in effect at least until Wednesday afternoon.
Starting at midnight, the city will offer free transit until the advisory ends. All transit buses will switch their digital signs to display stating Free Fare for Clean Air and will cover the fare boxes so passengers will not be able to deposit money.
