It was raining buckets at the Tanana Valley Farmer's Market in Fairbanks on July 9: a major turning point for Interior Alaska's fire season. Visitors dodged the downpour, hopping from one tent-covered stall to the next. Just a week before, thick wildfire smoke had kept many people indoors.
Amely Wernitz was visiting Fairbanks from Berlin. She came to camp, but got smoked out.
"It was a bit scary, because you can smell the fire and it's harder to breathe," she said. "And all the planes going by and the helicopters like that, was a bit scary at first."
University of Alaska Fairbanks student Erik Tansy, who was there to grab a bubble tea and shop for veggies, said he's glad the worst of the smoke has passed.
"Absolutely everything was just choked," he said. "The sun was orange."
Wildfire smoke isn't just irritating – it's downright unhealthy. Short- and long-term exposure can cause a wide range of health issues, from eye irritation to bronchitis, to heart problems. But researchers say there are still a lot of gaps in their knowledge about the smoke's movement and intensity because they don't have enough sensors in Alaska to get a complete picture. And the gaps get wider the further you get from major population centers.
The Alaska Department of Environmental Conservation is trying to address the sensor scarcity with a fleet of new air quality sensors, paid for by the federal Inflation Reduction Act and covid relief grants.
TJ Brado, a scientist with the department's Air Quality Division, is working with a number of partners — private, municipal, and tribal — to install about a dozen new sensors across Alaska to monitor wildfire smoke. He said those sensors could also help communities measure other pollutants.
"It could be cruise ship emission-related," Brado said. "Sometimes there are oil fields or other mining facilities that nearby communities want to kind of know if there's an impact at all to them."
But they're still trying to make those sensors Alaska-proof.
"When you get to 20 below, 30 below, 40 below, anything that's made of plastics can be really brittle," he said. "And so we've had to overcome challenges with that, power accessibility, and cell phone networks."
At the University of Alaska Fairbanks, researchers are working on another way to measure how bad the air is — and when it's time to head indoors.
Scientists consider fine particle pollution to be any kind of tiny airborne speck with a diameter of 2.5 micrometers or less. It's called PM 2.5, and it's usually assessed by satellites, which look at how much sunlight the pollution prevents from passing through the atmosphere.
But there's a lot of variation in smoke thickness in different layers of the plume that rises out of a wildfire. Satellites aren't great at finding that distribution, or at seeing how bad the smoke is near the ground, where it affects the air we breathe.
Tianlang Zhao is a PhD candidate at the University of Alaska Fairbanks, where he's studying the movement of air pollution. Last year, his research team started using NASA's Cloud-Aerosol Lidar and Infrared Pathfinder Observation Satellite and a computer model to penetrate those smoke plumes with math.
"We separate the intensity into five levels," Zhao said. "At the strongest level, we slightly adjust the factors so that the satellite data won't lead to so much of PM 2.5, and that can make our projection from the satellite more accurate."
Zhao's research group is also developing an app that would model this new observation method, showing users local smoke data and satellite forecasts.
Though scientists could be approaching a better understanding of what's going on in the skies above Alaska, they can't say how the rest of this year's fire season will go.
Wildfires have eased since late June, with the arrival of cooler, wetter weather. Evacuation orders have been lifted for many residential areas, and fire crews are gaining ground on the state's highest-priority wildfires. Still, the Alaska Division of Forestry says fire season could last for the rest of the summer.
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