How much microplastic is settling in Whitehorse each day? Researchers are just starting to find out

The results are in for a study in Whitehorse looking at the amount of microplastics in the city's air.

Based on the Yukon University's findings, an average of 10 microplastic fibres per square metre settle on Whitehorse each day about the equivalent of around4,238 single-use 500 millilitre plasticbottles.

Research over the last several years has highlightedmicroplastic pollution in oceans. This new research, published in October,took a look at how those tiny plastic fibres are affecting Whitehorse's air quality.

Yukon University instructor John Postma, who led the research, says though the finding on microplastics in the air in the city may seem like a lot, it's not as bad as in other large citiesglobally.

Postma spoke with CBC's Paul Tukkerabout the results of the study.

This interview has been edited for length and clarity.

Can you put this in a bit of perspective for us? Is 10 microplastic fibers per square meter per day settling in the city a lot?

It seems like a lot, but on global standards,it is actually quite good. Large mega-cities like Paris and London and Dongguan, China they're up in the hundreds, like 700 per square meter per day. So we're doing a lot better than that. More remote areas the French Pyrenees they were, for particles of this size ...at 36. So you know, worldwide, we're doing well It's not too bad, but it'd ideally be zero.

Back up a little bit and tell us why you wanted to measure this in the first place. What were you hoping to accomplish as you began this project?

We as a worldwide society are starting to recognize the hazards of microplastics. And they're not well studied yet. And we're starting to implement mitigation strategies for plastic pollution, such as the plastic bag ban at grocery stores. But it's very hard to measure the success of those mitigation strategies if we don't have a baseline.

So, one of the goals of this project was to establish a baseline for microplastic pollution airborne mircoplastic pollution in Whitehorse.

So how did you go about doing that?

We switched to a different [microplastics] collector in 2021, which could handle the winter. Basically, they're just metal cans that collect stuff [that] fall into them. Sowe're all familiar with dust settling on our counters, and inside our car dashes and stuff. Basically, this is just a little trap that catches them there's water in the bottom, so they can't fly out again.

Then we filter those samples every month, and then look at them under a microscope. There's a bunch of criteria we follow to see if it's microplastic, or inorganic fibre. That's subject to bias as pretty much everything humans dois. So then we use a hot needle. And we, under the microscope, put a very hot needle to these fibres and if it's plastic, it'll melt. And if it's an organic fibre, it'll burn and just disappear.

How surprising were the findings for you?

It wasn't that surprising. We knew it would be here, just because it's been everywhere in the world we've looked.

They're finding microplastics up on the Arctic ice cap. And those were not brought by the ocean, they were brought there by the atmosphere and the snow. So it wasn't that surprising. It's pleasing that it was actually kind of low. It's still a concerning number... There was quite a bit of fluctuation there. It went up to 29 fibres per square meter per day.

We don't know what these plastics do once they get into us and once they get into the organisms that many Yukoners rely upon for traditional foods.

It seems like we hear a fair amount about microplastics in oceans, but less so a bit microplastics in the air. Why do you think that is?

I think it is due [to the fact] they were first noticed in the ocean. I think it was in the shellfish, and mussels and clams and those type of animals that we do harvest and eat. So we started looking there first.

Then we started to notice in time that, hey, these things are on land, too. So how are they getting on land? And so the obvious answer for that one is the atmosphere is blowing them, they're very small particles, they can be carried, you know, 10s to 1000s of kilometres, depending on their size.

There's a growing interest in looking at atmospheric microplastic loads, and this study was to support that interest.

But there aren't that many places yet doing this type of research, I gather?

That's correct.

How come?

Cost prohibitive. So that was another goal of this study was to try and make an inexpensive sort of do-it-yourself style, atmospheremicroplastic apparatus. And we didn't design this apparatus, it has been used in other places on Earth. But one of the things we did a little more differently is we built everything locally, and just with regular materials that even remote regions most likely have access to.

The only thing they probably have to order is the filters, 1.6 micrometre filters. In comparison, to do a more high-resolution study and granted they are going to be more accurate the instrumentation is about $200,000, which now makes it cost-prohibitive to a great many people and organizations on the planet.

And in that case, you know, what's better? Do a lower cost, slightly lower-resolution study and have a baseline that we can compare with in the future, or just not do it at all?

What about here in Whitehorse, though, I mean, you mentioned this as a baseline. Is this something that can be you know, measured and monitored in a cost effective way in the years ahead?

Yeah, it's quite inexpensive to run. The project was originally called the Yukon microplasticstudy, because the goal was that we would do the communities and other more rural regions of the territory. COVID put a damper on that two times. Every time we were getting ready to go to a community, there was a "don't travel to the communities" warning for COVID. So that got scuttled. And we did some other sampling in the city here where we were allowed to travel.

But the hope is someday, there will be sampling and other communities in the Yukon's more remote areas to see what their microplastic deposition rates are like.

As you mentioned, still a lot of questions about the effect of these microplastics in the air. But what do you think can or should be done to reduce the amount of microplastics that we're releasing into the environment?

Oh, you said the key word there: "reduce." So the plastic bag ban is a good step at the grocery stores. We should just follow the three R's: reduce, reuse, recycle,in that order. The fewer plastics we use, the fewer plastics have the chance to escape into the environment.

What's the next step for your research?

We're hoping to get some community partners at some point and then do community sampling. Another interesting study that I've been thinking about is, a lot of the atmospheric plastic does come from the ocean when the waves break. So if you ever stand on a breaking beach, you'll notice there's sea mist and aerosols that form when the waves rate and some of those aerosols actually contain microplastics, which are then picked up by the wind and brought aloft again.

Whitehorse is in the rain shadow of the coast mountains to the west. So it'd be quite interesting to do a line of sampling from the B.C. border, so White Pass for example, to Whitehorse to see if there are more plastics closer to the ocean. And if so, that would suggest that the ocean is one of the sources for our airborne microplastics here.