By Laura Keil
Kinbasket Reservoir is not a significant contributor to Valemount’s air quality problems, according to a new report commissioned by the Village of Valemount.
During the Village’s June 15, 2021 Clean Air Task Force meeting, Nancy Chan, an air quality specialist with Hemmera, told the committee that the purpose of the study was to understand the contribution of Kinbasket Reservoir’s drawdown to the Village’s air quality and its impact on human health.
“Winds exceeding a certain threshold velocity when it blows over the surface of the sand, it can pick up the surface particles and transport it downwind,” she said.
She said the possible health effects come from a variety of possible sources such as particulate matter PM10 and PM2.5, crystalline silica (usually present in industrial settings, can cause lung disease) and amorphous silica (larger particles, more benign, no links to cancer). But she notes it’s unclear whether crystalline silica is present in the sand and more studies need to be done to determine that.
Hemmera Environmental Consultants analyzed seven years of PM10 and PM2.5 data from 2013-2019, data collected by the air quality monitoring station on the Valemount Courthouse roof. It found that the PM10 and PM2.5 levels in Valemount (from all sources) exceeded the BC air quality objectives during that time.
To study the impact of the reservoir, they took meteorological data and isolated 14 dust events on days when water levels were low, there was no rain, and wind was high and blowing north for at least two hours. Most of these events were between March and May when water levels in the reservoir were very low.
For the 14 events, they looked at how air quality levels changed and found that PM10 and PM2.5 increased, but the dust events typically only lasted a couple hours.
“These dust events are one hour—maybe two hours at the most—in duration,” Chan said. “So when you look at your daily 24-hour average concentrations, they remain below your BC air quality objectives for both PM10 and PM2.5.”
Chan noted a previous study by the Ministry of Environment determined that the primary sources of particulate matter came from wood burning and vehicle traffic.
“You have lots of other times when PM levels are elevated in the community and the magnitude of your 1-hour concentrations (from dust events) are not that high compared to other events happening in the community.”
She said the overall conclusion is the dust events from the Kinbasket Reservoir are infrequent, and while they elevate the on-hour PM10 and PM2.5 concentrations, they remain below BC air quality objectives. What they don’t know is how much crystalline silica is present in the sand and dust. She said they recommend testing samples of the sand and particulates in the air.
Gail Roth of the Ministry of Environment said it’s really good the village is reviewing the data to see what the biggest contributors of particulate are, since the purpose of the task force is to come up with ideas to improve air quality.
“It’s not to say that the reservoir dust never affects the community; members of the community know it does, and when it does it’s quite dramatic,” she said. “But even if those didn’t happen there would still be a big air quality issue in the town, so if we want to see an improvement, we really need to focus on those local sources.”
“There’s other sources that really need to be looked at,” said Mike Milner, of Hemmera. “Given that we’ve only seen 14 in seven years, that’s twice a year, you guys have other issues, the lower hanging fruit, so to speak.”
“There’s not many spikes in the summer. There’s a few in the spring, but the majority are in the winter, which leads you to the wood smoke issue,” Milner said.
“We know that wood smoke is a huge player with health,” said Counc. Hollie Blanchette.
Funding for the study was provided by the Provincial Government through the Ministry of Energy, Mines and Low Carbon Initiatives.