Holding Our Breath: Airshed Management Society works on the particulate problem

Photo Credit: Photo BC Ministry of Environment

Holding Our Breath: Airshed Management Society works on the particulate problem

👤Morgan Hite 🕔Apr 04, 2014

Feb. 6, 4 p.m. Smithers: -16 C, clear, with the slightest breath of wind at 0.5 metre/second from the northwest. PM2.5 is 34 micrograms per cubic metre.

After a week of cold, clear air sitting over the Bulkley Valley, I go into the Ministry of Environment offices in Smithers to talk to meteorologist Barry Watson. I want to ask him about air quality and how local weather can cause it to deteriorate.

He explains that this week is a classic example of weather and emissions combining to create bad air quality. We’re in a stable, high-pressure system, with very little wind. Everything being put out by wood stoves and industrial facilities is just hanging around.

“There are two things that you have to think of when it comes to air quality,” he says. “On the one hand, there are emissions into the atmosphere of a substance, such as particulate matter. On the other, there’s the ability of the atmosphere to disperse it.”

I’ve noticed that the air is having trouble dispersing particulate matter because I’ve been visiting bcairquality.ca to check the readings. PM2.5 is the measurement of particles in the air smaller than 2.5 microns and is the biggest health concern in our area. Hourly averages of PM2.5 concentration are automatically reported by monitoring equipment in Smithers, Telkwa, Houston and Burns Lake. On average, over a year, the numbers are below 8, but this hour in Smithers it’s 34. In Telkwa it’s only 3. In Houston and Burns Lake it’s 0 and 2.

While PM2.5 dispersion depends on the weather, sources depend on the season. Today it’s residential woodstoves, the forest product mills in Houston and Smithers, and the pellet plants in Houston and east of Burns Lake. In the spring it will include road dust. In the fall we’ll be contending with the smoke from burning forestry slash piles.

Since we can’t control the weather, it seems evident we have to control the sources of pollution. But, a little bit of particulate in the air—what’s the big deal?

Feb. 7, 8 p.m. Houston: -19 C, clear, wind one metre per second from the southeast. PM2.5 has been around 5 most of the day, but now it has risen to 36.

PM2.5 is not the smoke particles you can see and smell. PM2.5 particles, explains Smithers doctor Biz Bastian, are small enough to get deep into the lungs and possibly into the bloodstream. They damage blood vessel walls and can lead to clotting. In addition, they create an inflammatory response.

“Inflammation in the body has been linked with any kind of chronic disease development, particularly cancers and immune system problems,” she says.

In a study done at Smithers’ Bulkley Valley District Hospital during periods of high PM2.5, Bastian tells me, they expected to see more bronchitis, asthma and pneumonia. “But what came up as our number one admission during that time was men under the age of 30 with irregular heartbeats.”

As you might expect with a hazardous substance, the Ministry of Environment has a limit (called an air quality objective) for PM2.5. The number is 25, and PM2.5 has to remain there on average for 24 hours to trigger an air quality advisory. The 34 that I was breathing in Smithers did not trigger an advisory—it was just a spike on a day when the average reading was closer to 18.   

Sarah Henderson, a UBC researcher who has been studying the health effects of woodstove particulate, says that, on the whole, research supports 25 as a good, protective limit. But she cautions that we have to distinguish sudden exposure to high levels of particulate—a scenario in which otherwise healthy people are pretty resilient—from long-term exposure to low levels—a scenario that seems to lead to more and more health problems, specifically coronary disease.

As well, she argues that while air quality in BC may be better on average than it is in Ontario or China, we still need to advocate for constant improvement.

Feb. 8, 3 p.m. Telkwa: -18 C, clear, wind 0.6 metres per second from the north. PM2.5 has been below 5 most of the day, but now it has risen to 22.

The BVLD Airshed Management Society (AMS) was founded 10 years ago. It is a cooperative effort between the Ministry of Environment, mills, pellet plants and concerned citizens to improve air quality from Moricetown to Endako. “The idea of this group,” explains AMS secretary Greg Tamblyn, “is that everyone needs to do their bit—for everyone to reduce their emissions.”

Clean air is more than a health issue, points out Tamblyn. “There are people who have left the community due to air quality and there are people thinking of leaving. So it’s also a community development issue. If a place develops a reputation for bad air, people will find that a reason not to move there.”

Industrial sources produce a good bit of PM2.5. In 2012, the pellet plants in Burns Lake and Houston reported emitting 176 and 108 tonnes, respectively. Timber mills are smaller contributors, that same year showing PIR at 6.5 tonnes, CanFor 11, Houston Forest Products 7.9 and Babine Forest Products less than one. Ideally, all industrial sources stay up to date with the latest emissions-reducing technology.   

“The idea is continuous improvement throughout the industry,” Tamblyn says. For example, Pinnacle Pellet near Burns Lake will soon install a $5 million wet electrostatic precipitator to reduce its PM2.5 emissions.

An equally significant contributor is residential woodstoves. A 2003 study by UBC estimated that woodstoves in the airshed put out more than 340 tonnes of PM2.5 a year. They are a dispersed source, with stoves scattered all over the airshed, but where clustered together they can have a huge local impact. Mobile monitoring indicates that older, denser neighbourhoods and trailer parks often have worse air quality than town’s official monitor would indicate.

AMS’s woodstove exchange program, which ran from 2007 to 2013, attempted to clean up the worst emitters. Owners of classic airtight stoves, which have no ability to re-burn smoke, could trade them in and get a $250 rebate on a new, EPA-certified stove. Almost 650 stoves were switched out in the airshed. Colin McLeod, who directed the program, says that although it improved air quality in certain neighbourhoods, it didn’t do as much as AMS had hoped.

“I think where we hit the stumbling block,” he explains, “is that the new stoves are capable of burning 90 percent cleaner, but they require burning differently and, more importantly, burning seasoned firewood.”

Next, AMS will be taking a look at municipal bylaws and what role they might play in reducing PM2.5 emissions. If all this motivates you to get involved and maybe clean up your woodstove act, check out cleanairplan.ca.

Feb. 10, 9 p.m. Burns Lake: -13 C, wind 0.9 metres per second from the north. PM2.5 has been below 10 most of the day but is now spiking to 24.  

Thanks to the AMS, annual average PM2.5 numbers are declining slightly in the airshed. On the other hand, mobile monitoring shows that unless you live next to the town monitoring site, the official numbers may not represent the air you’re actually breathing.

We need to know more about how air quality varies throughout the airshed. And when we find out, there may be difficult societal and lifestyle choices to be made. Could we require woodstove owners to have licences? What if plants that couldn’t decrease emissions over time were shut down?

Take a deep breath and think about it.

Want to sound like a pro when talking to friends and family about air quality? Here are some terms you can casually drop.

PM2.5: Particles suspended in the air you breathe that are less than 2.5 microns across.

Air quality objective: The average concentration of a pollutant that the province considers acceptable for health purposes.

Air quality advisory: A public notification from the province that the air quality objective (25 micrograms per cubic metre) for the 24-hour average of PM2.5 has been exceeded.

Venting: The atmosphere’s ability to carry smoke aloft and disperse it.

Vertical mixing: Movement in the atmosphere that exchanges upper level and ground level air

Nephelometer: An air-sampling machine that measures particulate concentration in the air right here, right now.


The problem with any air quality index is that individual families can be exposed to levels of particulates much higher than that measured at a distant monitoring unit.  Dr. Moench of the Utah Physicians for a Healthy Environment speculates that exposure could be 100 times higher.  I am not sure about this but I have encountered levels 20 times that at a unit.  The point about long-term effects of low concentrations is important as. like cigarette smoking or second-hand smoke there is no safe exposure.  This is significant in relation to cancer as there are Class One carcinogenic vapours in wood fire emissions.  I identified formaldehyde, benzene and polycyclics in a typical wood burning area but this only hints at the problem. 
Canadian Clean Air Alliance