12-05-2025
Long-term efforts to clean air in Alaska's second-largest city are paying off
Smokestack emissions rise into the air on Feb. 7, 2025, above Golden Heart Plaza in downtown Fairbanks. Snow dusts the statute of the "Unknown First Family" that is the plaza's centerpiece. (Photo by Yereth Rosen/Alaska Beacon)
Just 140 miles south of the Arctic Circle, far from any major industrial or population centers, Alaska's second-largest city has struggled for decades with some of the nation's worst winter air pollution.
Now years of work to clear particulate pollution from the air in the Fairbanks North Star Borough, the approximately 7,500-square mile district encompassing the city of Fairbanks and its outskirts, is paying off.
At issue are the pollutants known as Particulate Matter 2.5, minute particles no bigger than 2.5 micrometers in diameter. Less than 5% the width of a typical human hair, they are health hazards. They can become embedded in the lungs and even pass through respiratory membranes to get into the bloodstream and body organs.
Since 2015, levels of those fine particulates – the majority of which has come from wood-burning stoves – have been roughly cut in half during the worst winter air-quality days.
'We have made tremendous strides in reducing PM 2.5 in the area, and I think that's something that needs to be acknowledged,' said Steven Hoke, the borough's air quality manager.
Fairbanks North Star Borough Mayor Grier Hopkins remembers past decades, when clunker vehicles filled the streets and poured smoky pollution into the air. That problem has largely been addressed by improved automobile technology and the diligent use of plug-in block heaters that improve engines' efficiency in cold weather. He also remembers old boilers that belched smoke, causing some to drift from the outdoor air into school hallways and classrooms. Those boilers have disappeared, and the difference is dramatic, he said.
'While we can have the reputation of some of the worst air in the nation, it doesn't feel like that when you're here,' Hopkins said. 'I would argue it feels a lot cleaner here when I'm walking around than if I'm in Los Angeles on a smoggy day or something like that.'
An important milestone came in the last days of the Biden administration, when the Environmental Protection Agency gave its blessing to the state's air plan for the Fairbanks North Star Borough. The tentative approval of what is known as the State Implementation Plan, or SIP, means that the borough will likely not face any additional air-quality related restrictions on construction or development at least until 2027.
There are still improvements to be made.
The borough continues to have occasional daily violations of air-quality standards in the winter. And there are continued state Department of Environmental Conservation advisories about health risks from particulate pollution, especially in the outlying community of North Pole, home to about 2,400 people, where inversions tend to be more intense. Over the winter of 2024-25, there were 32 such advisories issued for the borough.
Because federal standards on acceptable levels of fine particulates are tightened periodically, more progress is expected to be needed to meet future Clean Air Act requirements.
For Fairbanks, the air-quality challenge is stubborn, resulting from a mix of geography, climate and economics.
Like other cold-climate cities surrounded by mountainous regions, the Fairbanks area gets enveloped periodically in seasonal inversions, with stagnant cold air filled with ground-level emissions becoming trapped beneath warmer air.
'The cold air gets stuck in the valley and the warm air that's the wind and it's coming in from somewhere else just rides right over it,' said Bill Simpson, a UAF chemistry and biochemistry professor who studies Arctic air pollution.
Inversions are common elsewhere, in places like Denver, Salt Lake City, Calgary and Anchorage. Those cities, like Fairbanks, have contended with trapped particulate pollution during inversions.
But Fairbanks' inversions are more severe, more concentrated and longer lasting.
At this high latitude, there is little winter sunlight to overturn and weaken inversion layers, as happens in Rocky Mountain places like Salt Lake City and Denver. This far inland, there is no ocean breeze to disrupt the inversions, as happens in Anchorage or in Scandinavian cities.
The lack of winter sunlight and lack of ground-level heat and wind compresses the Fairbanks inversion layer to only 230 feet or so, Simpson said. Layers in Lower 48 sites are typically at least twice that high, Simpson said, making their particulate pollution more dispersed.
Once an inversion sets it, violations of the Clean Air Act's 24-hour standard for fine particulates often follow, Simpson said.
'When there's a really bad day, it's just really hard to avoid because the boundary layer is so shallow,' he said.
Fairbanks inversions can persist for days, creating temperature differences between high and low elevations that are much as 30 degrees Fahrenheit. Levels of fine particulates within those inversion pockets, though much lower than they used to be, are typically close to twice the regulatory limit of 35 micrograms per cubic meter, according to the EPA.
Inversions are a fact of life for residents, like the West Valley High School ski team members who congregate for practices and competitions at Birch Hill, the cross-country venue on a ridge rising more than 1,000 feet above the city.
'If it's cold, you don't go on White Bear. It can be like a 20-degree difference sometimes' said team member Maya Griek, referring to a long trail that loops down to the ridge's lowest elevations.
While there are multiple contributors, from big coal-fired power plants to small local coffee roasters, the primary reason for Fairbanks' winter air pollution is relatively simple. It comes down to what people burn to stay warm and how they burn it.
That also makes it hard to control.
Fairbanks temperatures can dip below minus 40 degrees Fahrenheit, and residents rely heavily on woodburning stoves as either main sources of heat or supplemental sources and where natural gas options are limited. That is a contrast to cities like Anchorage and Calgary, where most indoor heat comes from natural gas, or Scandinavian cities, where heat pumps and geothermal energy are widely used.
On the coldest days, severe inversions and pollution problems are most likely — and the desire to burn wood is the highest. But those are the days when burning is banned.
Burn bans have been unpopular. In 2018, voters passed an ordinance stripping the borough of enforcement powers on air-quality matters. Enforcement of bans and other matters, as a result, is up to the state.
That means the borough's job, as Hopkins and Hoke describe it, is to monitor, provide opportunities for cleaner air and encourage residents to do the right thing.
'You can't convince somebody to do something they don't want to do,' Hoke said. 'The best way to get them to do that is get them to see the benefits and then to convince themselves.'
Since wood burning remains the top source of particulate pollution, much of that encouragement has focused on better wood stoves.
Since 2010, the borough, state and EPA have collaborated on a stove-trading program that enables people to replace inefficient stoves with modern versions. From 2010 to 2024, 4,783 old wood-burning stoves were swapped out for upgraded heating devices, according to the borough's records.
Officials are also pushing residents to burn better wood. Kiln-dried wood, which burns more efficiently and produces less particulate pollution, is an important element of the newly approved plan.
Such wood has been offered since 2020 by a company called Aurora Energy Solutions. It has two kilns to process mostly birch, though some spruce is in the mix as well.
Birch, a hardwood, is the main firewood source in Interior Alaska. Though ubiquitous in the region and readily available through timber sales held on state land, it contains large amounts of water that can make burning slow and smoky.
The moisture content in delivered birch logs can be as high as 50%, in the form of liquid water in summer and ice in winter, said Susan Shopper, the general manager.
The kilns, which are heated to 230 degrees, convert most of that moisture into steam that is released into the air. The resulting product has a moisture content that is no higher than 20%. The company aims for even lower levels that are in the teens, Shopper said.
There is high demand in winter for the dried wood, which costs money up front but saves it in the long run, she said.
But when it comes to meeting that demand, there is a seasonal mismatch.
The best season for drying wood is summer, when the coal-fired electricity plant across the street has the most excess steam power to sell to the kiln operation. It generally takes 4 ½ days to complete a wood-drying cycle in the winter; in summer, that time is cut to two days, Shopper said.
The worst time to dry wood, or to buy dried wood, is the dead of winter, when people want it the most.
During the hot, around-the-clock summer daylight, it can be a challenge to get customers to think about stocking up on wood for the cold, dark winter to come, Shopper said.
'Processing and drying in the summer is very advantageous for us economically. But that's not what people tend to want to buy firewood, so it's kind of hard,' she said.
While the characteristics of Fairbanks' air-quality situation make it tough to address, they also fascinate scientists.
In 2022, nearly 50 scientists from North America and Europe gathered at UAF for a project to examine details of the borough's air quality. The Alaskan Layered Pollution and Chemical Analysis project, or ALPACA, was not focused on regulation, but the information has proved useful to agencies and to people trying to address air-quality problems in other far-north and mountainous regions that also face inversion challenges.
For seven weeks, the group made detailed measurements of air quality and weather conditions at varying atmospheric layers. They also examined indoor air quality and the interplay between indoor combustion and outdoor particulates.
Their studies have explored not only what goes into the air but how different pollutants react with each other once emitted, said Simpson, the project's leader.
While woodsmoke is the underlying problem, emissions from other sources like power plants and heavy diesel-burning vehicles compound it, as different pollutants' molecules bond with the woodsmoke molecules.
One important finding is that sulfur, a byproduct of diesel, oil and coal combustion, is a significant problem. Through that chemical bonding process, sulfur is responsible for about 20% of the particulate mass, Simpson said.
Information about sulfur's proven contribution helped lead the EPA to propose a mandate for ultra-low-sulfur fuel for those businesses and residents that burn diesel.
But state and borough officials convinced federal regulators that such a requirement would be counterproductive because the high cost of ultra-low-sulfur fuel in such an isolated market would drive some Fairbanks residents to burn more wood, even if they did so on the sly during ban periods.
A compromise that went into effect in September 2022 is a state regulation requiring low-sulfur in the Fairbanks area, but not ultra-low-sulfur fuel. While regular fuel has sulfur levels of about 2,000 parts per million, lower-sulfur fuel has half that. Ultra-low-sulfur fuel, in contrast, has no more than 15 parts of sulfur per million.
Simpson said that the compromise has been effective in reducing the sulfur dioxide.
'What we've seen is that the SO2 in the atmosphere is cut in half. It's really, really worked to clean up the amount of sulfur in the atmosphere,' he said.
Could Fairbanks ever be entirely free of winter woodsmoke? It seems unlikely in the near future
The particulate-free source of energy used for heat elsewhere in Alaska – natural gas — has limited application in Fairbanks. The borough-owned Interior Gas Utility provides liquefied natural gas that is delivered by truck to about 3,000 customers. The utility touts the air-quality attributes of natural gas with a simple slogan on its website: 'Breathe Easy.'
However, Fairbanks lacks the grid connections and economies of scale that make natural gas the dominant energy source in Anchorage and other parts of Southcentral Alaska.
To Hopkins, a wholesale switch to natural gas may be desirable from an air-pollution standpoint, but it is not realistic.
'The problem is even if you get a gas line coming through Fairbanks, you're never going to get infrastructure to a place that's the size of Connecticut when you only have 100,000 people in the area. It's too dispersed,' he said.
The challenging atmospheric inversions will remain, he notes. So will the winter cold, which means the appeal of wood and woodburning will endure among many residents.
Continued access to better stoves and better wood is a practical way to benefit both air quality and residents' pocketbooks, he said.
'People see that it works. People see the financial savings to themselves,' he said.'
This story has been supported by the Solutions Journalism Network, a nonprofit organization dedicated to rigorous and compelling reporting about responses to social problems,
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