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Spruce pollen is more than three times the size of birch and alder pollen because the main body of the pollen grain is surrounded by two air sacs that allow wind transport. Heavy concentrations of spruce pollen can often be seen as a yellow coating on puddles or yellow dust on the surface of a car.
Courtesy Susan Harry
Birch catkins signal what many allergy sufferers in Fairbanks already know — that pollen season is upon us.
Spruce pollen is more than three times the size of birch and alder pollen because the main body of the pollen grain is surrounded by two air sacs that allow wind transport. Heavy concentrations of spruce pollen can often be seen as a yellow coating on puddles or yellow dust on the surface of a car.
The red dot with three pores at the top right is birch. The red dots with five pores in the middle are alder
The big clump in the middle is comprised of birch pollen.
Susan Harry
For the past 25 years, Susan Harry has been peering into a microscope every spring to count and classify minuscule grains of pollen.
It’s a task that can take a few minutes up to an hour and a half at the height of pollen season, in May and early June.
She found the task interesting but not personally noteworthy until she noticed her toddler son getting sick every spring.
“I thought maybe he’s got allergies,” Harry said. “And, of course, he did. It was one of those things where it crossed over into my personal life.”
Harry also developed allergies. “I kind of know what’s going on without actually looking at the microscope, like pretty much anyone else with allergies,” she said.
For decades, Harry’s pollen counts were displayed by the allergy clinic at Tanana Valley Clinic in Fairbanks. More recently, she has been working with OneTree Alaska at the University of Alaska Fairbanks.
The counts are hosted on the UAF Cooperative Extension Service website, bit.ly/FairbanksPollen.
Harry, the lab and safety coordinator for the UAF Department of Veterinary Medicine, started counting pollen this spring on April 20 but only found about six alder grains. She plans to count two to three times per week through July or August. Typical pollen sources are birch, spruce, alder, willow, sedges, grass and mold.
Harry said the count was originally a way for allergists and allergy sufferers to track what was in the air and making people miserable. Over the years, researchers from around the world have become interested in the data, which is being used in climate studies.
Papers published by researchers using these pollen counts show longer pollen season lengths. Fairbanks, in particular, is having longer and more intense seasons. In 2020, a sudden warmup after a cold spring triggered an explosion of birch pollen, setting a world record.
This spring, Harry received certification from the National Allergy Bureau, which maintains a nationwide database of pollen counts. To become certified, candidates must take an aeroallergen course and successfully complete a 70-question multiple-choice test and a slide identification exam.
“I began this process many years ago, but the identification portion was especially difficult since we have only four to five main pollen types here,” Harry said. “The slide is based on pollen found in the Lower 48, so most of the grains were ones I never see here in Alaska. We don’t have oak. We don’t have maple. We don’t have any of those things in Alaska, unless it’s ornamental. So that made it a little challenging for me. There was birch. I was pretty solid on that one.”
The certification means that Harry’s pollen counts will also be displayed on the NAB site, https://pollen.aaaai.org/#/.
Pollen is collected using a tool called a rotorod on which silicone grease is spread. The rod turns on a schedule and pollen sticks to the grease. After 24 hours, the pollen is collected, stained and counted under a microscope. That raw data goes into a formula that gives the pollen count per cubic meter, which is the number Harry reports. It is something that allergy sufferers track closely.
With the certification, Harry can now train others to do the pollen counts, which will give her a backup for times she isn’t available.
“It started as this kind of curiosity and something to do that’s outside of my normal job,” she said. “And then I just kind of went with it.”
Contact Julie Stricker at jestricker2@alaska.edu.
