‘We are expecting it to get worse,’ Calgary Region Airshed Zone program manager Mandeep Dhaliwal says of the outlook for Calgary’s air quality.Chris Bolin/The Globe and Mail
Smoke from fires raging in the northwestern U.S. and British Columbia has blanketed much of downtown Calgary in a thick haze this week. On some days, concentrations of dangerous particulate matter have surpassed levels more commonly associated with smog-choked cities, such as Beijing, New Delhi and Los Angeles.
Mandeep Dhaliwal, air quality program manager with the Calgary Region Airshed Zone, spoke with The Globe and Mail.
How would you rate Calgary's air quality this week?
The pollution was not only similar to some of the other parts of the world, but it was actually worse than places like Beijing, New Delhi and L.A. in terms of the particulate matter that we're experiencing.
In the air, there's a lot of contaminants. We only monitor the ones that are called criteria air contaminants that are known to cause significant health hazards. There's no point in monitoring everything else in the air. PM 2.5, which is short for particulate matter, is one of those criteria air contaminants.
We have three continuous monitoring stations in Calgary. They monitor all criteria air contaminants, and all three of them monitor PM 2.5, so we have continuous analyzers that give us one-minute averages. However, we are only required to report one-hour averages. We monitor one-hour average of PM 2.5 and compare it to Alberta ambient air quality guidelines.
Back up. What is 'PM 2.5' and why is it dangerous?
Particulate matter, or PM, is any tiny solids or suspended solids in the air. In layman's terms, you can call it dust. Or you can call it ash. Depending on the size of it, then we have a different name for it. Anything bigger than 100 microns in diameter – a micron is 10 to the negative six – we call them TSP, total suspended particulates.
Two-point-five microns is so small it's about 30 times smaller than a human hair. So forget about even seeing that; our body does not even know that we took it in. Our lungs don't know it. Our throat doesn't feel it. You do feel the after-effect of it; you'll get throat irritation.
But in the beginning you will not notice that you are breathing it in. So, if you're walking around and you're breathing in PM 2.5, there's no way you can tell . As compared to dust, you'll know right away.
What are the risks of exposure?
What it does is it goes right into your lungs, deep into your lungs. There's a lining inside our lungs called alveoli, and it sits there. That's exactly where the air or oxygen exchanges with the bloodstream. These little tiny solids go right into our bloodstream.
The immediate effect of exposure could be lung inflammation. It can aggravate your asthma or any other pre-existing conditions you have. Chronic exposure of high levels of PM 2.5 can even lead up to lung cancer.
How do this week's conditions compare to a typical day?
On a typical day, on a regular day, you'll have concentrations of PM 2.5 in the air anywhere from 10 to 30 micrograms per cubic metre.
Approximately 70 per cent of our PM 2.5 comes from man-made sources. So it's you and me driving vehicles, or construction vehicles. It's elevated at the moment due to the fires in the Washington area. PM 2.5 can travel tens of thousands of kilometres away.
We experienced this back in 2003, when we had lots of forest fires happening in and around Calgary or even further away. At that time, actually, our highest concentration of PM 2.5 did go above 200 micrograms per cubic metre. In this episode, a couple days ago, we reached it up to 186.
What's the outlook?
We are expecting it to get worse. The forest fires are not stopping in Washington, and the Weather Network is predicting the winds are going to come our way. We are expected to get more of that again. Who knows, we might even exceed the levels that we had back in 2003.
This interview has been edited and condensed.