Calibration error results in Kitimat air quality station reporting huge SO2 concentration

A calibration of equipment at an air quality station in Kitimat raised eyebrows with an SO2 level well above the norm.

If an air quality graph on the provincial government’s air quality website was to be believed there was an hours long spike in sulphur dioxide (SO2) on November 6 that went several times over the provincial standard.

However a more than 200 parts per billion (ppb) reading was a technical error relating to the machine’s automatic calibration which isn’t supposed to even be published, according to the ministry.

The Kitimat for Clean Air Facebook group shared a screenshot of the readings showing an uncharacteristic rise in SO2.

Barry Watson, an air quality meteorologist for the BC Ministry of Environment, explained the error.

“It’s basically a calibration, it’s erroneous data,” he said, noting the machines self-check themselves which involves inputing false data. “That information goes through a quality control to calibrate itself…so it artificially puts in numbers to check its calibrations.”

“They’re not supposed to be published,” he added.

He said the wrong data, which has since been corrected on bcairquality.ca, showed from 3 p.m. to 7 p.m. on November 6.

A number for SO2 in the hundreds would be alarming as Watson says the provincial standard is 75 ppb over one hour.

A five-day graph at the time of writing showed SO2 readings at Riverlodge’s station now peaking at approximately 8 ppb late on November 4.