A dust advisory continued for a second day in a row on Friday before coming to an endlate afternoon after the reading for coarse particulate at the Ministry of Environment's downtown monitor fell below the threshold for triggering the warning.
As of 4 p.m., the reading for PM 10 at the Plaza 400 station was 47 micrograms per cubic metre, compared to 68 as of 9 a.m. Advisories are issued whenever a reading hits 50.
"Based on the air quality data, the high levels were mainly due to road dust in the bowl area," Northern Heath and Ministry of Environment officials said in a news release.
The afternoon reading at College Heights was 23 and at the BCR industrial site it was 38.
For fine particulate, or PM 2.5, the readings were six downtown and four at College Heights. An advisory is issued whenever the reading reaches 25.
