Photo: The Canadian Press

Smoky skies in Kamloops in late July.

A group of Kamloops doctors has serious concerns about air quality index ratings in B.C.

Kamloops Physicians for a Healthy Environment Society sent a letter to deputy provincial health officer Dr. Bonnie Henry this week urging the province undertake a review of the impact of forest fire smoke on the health of Interior residents.

They are also concerned by recent statements to the media that exposure to continued heavy smoke from numerous wildfires in the region poses no long-term health impacts for the majority of the population.

“We don't expect to have long-term health effects from this type of exposure like you would, for example, with ongoing issues with air pollution in a city like Beijing," Henry told Radio NL in Kamloops.

The city has experienced an unprecedented run of smoky skies since July 1, the doctors say.

Between July 31 and Aug. 12, hourly concentrations at the Aberdeen monitoring station in Kamloops reached as high as 364 micrograms per cubic metre and 862 in downtown Kamloops. B.C.'s air quality objective calls for a maximum daily average of 25 micrograms.

"The group feels medical literature has spoken clearly about the dangers of forest fire smoke and high short-term air pollution exposure," said spokesperson Dr. Jill Calder.

Meanwhile, Dr. Michael Mehta, a professor of geography and environmental studies at Thompson Rivers University, says the Air Quality Health Index used to measure pollution downplays exposures from particulate pollution.

"How much is a human life worth? If you live in rural British Columbia or in resource-based communities like Kamloops, you may be surprised to learn that your life is worth far less than someone from Vancouver or Victoria," he claims.

Mehta says recent forest fires and the massive amounts of wood smoke produced demonstrate how the AQHI treats air quality differently depending on where you live. 

The AQHI weighs the relative contribution of three air pollutants: particulate matter in the 2.5 micron range (PM2.5), ground-level ozone, and nitrogen dioxide. Ratings range from one to 10, representing a low to very high health risk, but reached 49 on Aug. 3 in Kamloops.

Mehta says the system downplays the significance of particulate matter in smoke, favouring urban areas where tailpipe emissions are more prevalent.

"For example, a community exposed to no nitrogen dioxide, no ozone, and 100 micrograms/m3 of PM2.5 pollution yields an AQHI of 5, or moderate risk. This is actually a staggering amount of pollution, yet the risk messaging is tempered and muted," he says in a research paper.

"It would take 400 micrograms/m3 of PM2.5 with this scenario to hit a 10 on the AQHI. China issues 'red alert' warnings when 24-hour averages exceed 150 micrograms/m3."