When Smurfit-Stone Container Corp.'s linerboard plant in Frenchtown stopped making paper last week, it also stopped spouting what for years has been the largest plume of emissions rising out of the Missoula Valley. Air quality experts say the reduction in particulate matter could improve Missoula's air quality, just as it teeters on the edge of violating the U.S. Environmental Protection Agency's (EPA) standards.
According to a 2007 study conducted by the University of Montana and the Missoula City-County Health Department, emissions from Smurfit-Stone's kraft recovery boiler accounted for 7 percent of Missoula's ambient PM2.5 (particulate matter less than or equal to 2.5 microns in diameter).
In addition, the hog fuel boilers at Smurfit-Stone, the Stimson Lumber Co. mill in Bonner (which has also since closed) and the Roseburg Forest Products plant on Missoula's Westside together accounted for 11.7 percent of that particulate matter.
So will Smurfit-Stone's closure bring with it some modicum of good news for Missoulians' lungs?
"It's so weather dependent," says Ben Schmidt, a Missoula County air quality specialist. "I really don't know if it's going to be an important factor or not. If you still look at all the sources, even with all the wood stove regulations we've done in the urban area, residential wood combustion still causes the majority of the air quality issues that we have. And that's what it is throughout all of western Montana."
Wood combustion, according to the study, accounted for 55.5 percent of particulates in Missoula's air.
"If you get, let's say, seven days with inversions and no frost to help pull particulates out of the air," Schmidt says, "whether Smurfit-Stone is here or not here, it's irrelevant: We're in trouble probably."
The EPA changed its air quality standards for PM2.5 in 2006, dropping from 65 micrograms per cubic meter for the 24-hour standard down to 35, and putting Missoula very close to "non-attainment."
Beyond particulates, the Smurfit-Stone smokestack also released, according to a 2008 Department of Environmental Quality emissions inventory, some measures of carbon monoxide, ammonia, sulfur dioxide, nitrogen dioxide and volatile organic compounds.