GRAND FORKS-Although the air remains relatively clean in North Dakota and Minnesota, according to each state's division of air quality, the organizations have shifted their concern to smoke from wildfires in the western United States and Canada during the past couple of years.
"On a typical day in North Dakota, it's very clean air," said Ryan Mills, who manages North Dakota's Department of Ambient Air Quality. "We definitely hold our heads pretty high on that. We've had some of the cleanest air in the nation, and as of late, the only issues we have had are from forest fires."
Levels of pollutants from vehicles and stationary facilities-including carbon monoxide, oxides of nitrogen, particulate matter and sulfur dioxide, all of which cause respiratory difficulties-remain low in North Dakota, Mills said.
In September, his division released a report on last year's air quality, sharing data the state gathered from monitoring sites across the state, located mostly in the west where the oil fields are. The report also uses self-reported data from companies that produce air pollutants.
"They're required by law to submit their emission report every year," Mills said.
His report only lists facilities that release at least 100 tons of a pollutant per year. American Crystal Sugar Co. frequently made this benchmark and was one of the state's highest polluters last year.
"It's not that there's any issue with them. They're just our bigger sources, so that's why we have them in our report," Mills said.
Most notably, the company's Hillsboro plant was No. 1 on a list of facilities that had released 100 tons or more of carbon monoxide in 2017. Its plant in Drayton was No. 1 on a list of locations that had released at least 100 tons of PM 2.5 in 2017, that being one of two types of particulate matter according to National Ambient Air Quality Standards. On a list of PM 10 contributors (a second, chunkier particulate matter), the Hillsboro and Drayton plants were No. 7 and 8, respectively.
The company was mentioned several other times for releasing at least a hundred tons of sulfur dioxide, oxides of nitrogen and volatile organic compounds.
Minnesota fined American Crystal's plant in East Grand Forks last year for exceeding its maximum emission limits up to 280 times over a three-year period, the state said. Last year, American Crystal disputed these claims before paying a $135,000 fine and agreeing to help reduce the amount of hydrogen sulfide it was releasing.
Outside the Red River Valley, Minnkota Power Cooperative's power plant near Center, and Dakota Gasification in Beulah were also listed among several other contributors in North Dakota. Dakota Gasification was the only facility reported that released at least 100 tons of ammonia last year.
In North Dakota, plants like American Crystal are allowed to emit as many pollutants as their permits allow. Beyond that, facilities also have to follow restrictions specified in the National Ambient Air Quality Standards, which Mills at the Division of Air Quality follows. No North Dakota industry violated those standards last year, he said.
In Minnesota, Air Quality Meteorologist Daniel Dix said he's noticed many industries are reducing their emissions by switching from coal to natural gas. The University of North Dakota, which was also listed on the North Dakota's Ambient Air Quality report this year for its heating plant's sulfur dioxide emissions, will make this change within the next couple of years.
"As far as industry, with regulations and permitting that all the states are doing, I think that's helped significantly," Dix said. "I think the focus of the future is going to be vehicles, as they transition to less gasoline power and electric, and wildfires."
In North Dakota, Mills said his division started seeing more particulate matter in the air than normal due to wildfires. The state's worst year on wildfire record was in 2015, Mills said, when he recorded the most days with elevated particulate matter.
Dix said his group of meteorologists were previously only working in the Twin Cities and Rochester area when they started to notice more wildfires affecting the air quality of the state. "So we said hey, we can expand this forecasting statewide and help do a better job of air quality alerts and all that," Dix recalled.
Now Minnesota's Pollution Control Agency has an office of Air Quality Dispersion Modeling.
While neither state can do much to prevent wildfires from happening across state borders and in Canada, Dix said Minnesota advises people to limit pollutants and emissions as much as possible when wildfires are raging far away. Residents can reduce their trips and car pool or convert to electric vehicles.