Smog covers the Salt Lake Valley during a typical winter inversion. Photo courtesy University of Utah.
By Andrew Haley
One thing is clear: last winter’s heavy smog besmirched Utah’s reputation as an idyllic winter playground and imperiled the health of residents along the Wasatch Front. In January, thousands of out-of-state visitors arriving for the Outdoor Retailer Winter Market and the Sundance Film Festival took home stories of Utah’s terrible air quality, prompting a flurry of bad press from the national news and further enraging locals, who marched on the state Capitol in gas masks and took to social media to protest area industries. But populist anger about the situation, while justified, may fail to understand the complex issue of what causes these inversions, as they are locally known, and how state, county and municipal governments, industry, and citizens can help mitigate the problem.
The primary culprit, known by its government moniker as pm2.5, is tiny particulate matter smaller than 2.5 micrometers trapped in cold air bottled under a layer of warm air that sits like a lid over the mountain valleys of the Wasatch. The majority of the particles are tiny crystals of ammonium nitrate that form like a crust when ammonia and nitrogen gasses mingle in the air. During a strong inversion, which to meteorologists refers not to air pollution but to deviations in normal atmospheric patterns that see normally warm air closer to the ground replaced by unusually cold air that shuts down the natural convection cycle, levels of pm2.5 build and build until they muddy the air and become toxic.
Area residents who point fingers at Kennecott and other Salt Lake County and other Wasatch Front industries misunderstand the sources and, ultimately, the causes of so-called inversions. Patrick Barickman, an environmental program manager at the Utah Division of Air Quality (DAQ), said annual measurements of emissions inventories in the airshed show that industry sources, including Kennecott and five major refineries, produce a fraction of Wasatch Front pollution, while passenger vehicles produce more emissions than all other sources put together.
“When we sum those [sources] up, what we have in our inventory in the Wasatch Front counties is industry is a little over 10 percent and auto and other area sources make up the other 90 percent,” Barickman said.
“It’s mostly cars.”
A full 57 percent of pollution in Salt Lake County comes from passenger vehicles on freeways. Area sources, such as restaurants char broiling hamburgers, snow blowers, auto body shops spraying on a new paint job and cozy wood fires account for 32 percent. Of the remaining 11 percent, Kennecott contributes less than half, accounting for 3.5 percent of total emissions in the county.
“What the data tell us is that it’s relevant to make cuts to industry, but if it only makes up 10 percent, you can make pretty big cuts and have a smaller effect overall,” Barickman said.
“We are reducing emissions more when we project out into the future, and we’re not saying industry is only 10 percent so let’s leave them alone, but I guess the low hanging fruit is gone. We still have reductions that need to be made, but controls get more and more expensive. You get to a certain point where it gets more expensive to get that last little bit, and that’s where we’re at now,” he said.
Complicating the issue, Barickman said that while anecdotally this past winter’s inversions were among the worst in memory, overall pollution levels are down. Emissions in Salt Lake County dropped close to 20 percent between 2002 and 2008, he said.
“I was surprised by this and I’ve worked here for 20 years,” he said.
While prolonged temperature inversions may trap more pollution in the long run, the amount of pollution they start off with is down, making a dramatic solution to the air quality problem even more unlikely.
“I’m not an apologist for Kennecott, nor do I think they are the silver bullet, not only them but the refineries. They’re players, just like everybody else is, but it’s pretty simple arithmetic: if you doubled their emissions to 20 percent, it’s still only 20 percent,” Barickman said.
“It comes back to the issue of meteorology. You do kind of reach a level where you can’t do much really. You get to the point where you have to start shutting down parts of industry to have an effect. When an inversion sets in, it’s not locally generated. There’s just variability in the weather,” he said.
University of Utah professors David Whiteman and John Horel are leading an ongoing, $1.3 million, three-year study of Utah’s atmospheric conditions in order to better understand the causes — and hopefully the solutions — to the state’s terrible winter air quality.
“The presence of inversions is tied directly to the weather, and there is no trend in their prevalence over the last 20-30 years,” Horel said by email.
“The weather ingredients that make our cold-air pools (the layer below the trapping inversion filled with pollutants) is the often elevated inversion or strong stable layer, weak winds within the cold air pool limiting mixing, and the presence of snow cover. Those can happen at any time during the period from December through February. That is the random element. But, the randomness of when such events may happen during a particular winter is of much less importance than the need for planning and regulation for mitigation of the worst cases, such as this past winter,” he said.
“As a citizen living in the valley, there are things all of us can do to reduce emissions more than at present that go beyond what is required now (i.e., no drive or highly restricted driving days). It will become increasingly critical to do so as we have no choice if the health of people along the Wasatch Front is to be protected,” Horel said.
Whiteman said that a key part to solving the air pollution problem lies in understanding that once a prolonged inversion sets in, pm2.5 levels build quite quickly. He said that primary sources of pm2.5 and other chemicals that bond together to form pm2.5, so called secondary sources, generate enough of the dangerous particulate matter to exceed the Environmental Protection Agency’s pm2.5 limits of 35 µg/m3 (micrograms per cubic meter), in four days, once an inversion has trapped pollution in the Salt Lake Valley. Inversions lasting five days or more cause the build up of pm2.5 to considerably exceed those levels.
“You’re not going to be changing the weather. You get what you get. But the pollution we’re getting depends on how long these last,” he said.
Further exacerbating the problem are higher average temperatures that increase overall humidity, Whiteman said.
“There are a lot of different effects of humidity. Let’s say you have a fog. There are a lot of different chemical reactions in air that lead to pm2.5. There are probably different chemical reactions that occur in aqueous solutions that in clear, dry air. Pollution particles in humidity attract water droplets and grow,” he said.
Not only do fogs aid in the production of harmful chemicals, supercharging the secondary sources of pm2.5, once morning fogs dissipate on cold, clear days, they rise into the air and form a stratus layer of high, thin cloud cover, Whiteman said.
“When we have stratus layers in the clouds, we get better mixing. So instead of having layered smog, it’s mixed through the shallow layer,” he said.
While rising temperatures bring increased humidity, and increased humidity aids in the growth of secondary pm2.5 and in the mixing of air pollution in the lower air, overall, the big culprit remains the inversion itself, and whether or not it appears. While temperature trends are creeping up around the world, Whiteman said that the occurrence of severe, prolonged inversions remains random.
“Looking back 38 years, there’s a huge variation in temperature inversions. I don’t see any trend in that,” Whiteman said.
The chief culprit of last winter’s terrible air was not the Kennecott smoke stack, or even rush hour gridlock choking the freeways, but a high pressure system over the Pacific that wobbled eastward over the Rockies and pinned pollution to the ground. According to one area doctor and air quality advocate, concentrating on those super-sized weather patterns instead of the local sources of pollution only exacerbates the problem.
“I think people all too often focus on our inversions when they want to talk about air pollution,” Dr. Brian Moench said.
Moench is president of Utah Physicians for a Healthy Environment and an anesthesiologist in private practice.
“While inversions get most the attention, and EPA standards we're in violation of, the issue of air pollution is its impact on public health year round. Our air pollution problems are more than inversions,” Moench said.
While pm2.5 levels can reach upwards of 90 µg/m3 during a severe inversion event, dust storms out of the west desert can drive up pm2.5 levels to over 250 µg/m3, he said. According to Moench, dust blown off the dry lakebed of the Great Salt Lake, off Kennecott’s tailings piles, from gravel pits and off the west desert can contain high levels of heavy metals such mercury and even radioactive fallout scattered decades ago by above ground nuclear testing in neighboring Nevada.
“Not all pm2.5 is created equal,” Moench said.
“The fact that heavy metals are attached to it is not brought up because the DAQ is focused on meeting national regulatory standards. Whatever particulate matter has heavy metals attached to it is especially toxic,” he said.
Moench said while their total emissions levels might fall within federal standards, and their percentage contribution to the total amount of pm2.5 might be minimal, Kennecott and the refineries had an outsize negative effect on public health because of benzene related emissions from the refineries and other heavy metals exposed by Kennecott’s mining activity.
“Heavy metals are not biodegradable, they are not combustible, so literally for 100 years dust from Kennecott’s operation drifts over the rest of the valley and anything like Geneva that throws up dust is likely to kick up heavy metals from Kennecott’s operation,” he said.
Moench said there are practical steps to solving the Wasatch Front’s bad air problem.
“First off, we need to acknowledge that it isn’t just inversion events we need to worry about,” he said.
Since the leading two emitters of pollution along the Wasatch Front are cars and homes, a robust mass transit network and bans on certain activities like burning wood for heat would have a tremendous impact on air pollution, he said.
“We need to stop funding new highways and start funding mass transit. The more freeways we build, the more pollution we’re going to generate. Wood smoke is highly toxic. [Burning wood] really is a 50 or 60-year old idea that needs to change. Woodsmoke may be 10 times more toxic to the lungs than urban smog. We need to phase out the wood burning period and help people who are dependent on it for heat,” Moench said.
“The dangerous mindset of the legislature is they don’t see other communities doing much so they figure we don’t have to either, but they don’t take into account our unique geographic circumstances with mountains on both sides,” he said.
While the pace of change may be slow in the state legislature, that is not the case at Kennecott, said Kennecott Utah Copper spokesperson Kyle Bennett.
“We have been highly regulated since the Clean Air Act was passed in 1970. We have invested a lot in capital, and a lot in our employees to create behavioral change. There has been some great progress,” he said.
Bennett said Kennecott had poured well over $1 billion in capital upgrades into the mine since 1970. Its mid-1990s smelter modernization alone cost $1 billion, while recent acquisitions of 22 enormous haul trucks, at $3.5 million each, cost $77 million. Two decades later, the smelter remains one of the cleanest and most modern in the world, and, because of their greater size and efficiency, the new haul trucks reduced the mine’s haul truck emissions by half, he said.
According to Bennett, further efforts are under way to convert the mine’s enormous fleet of small trucks to compressed natural gas, and a no-idling policy encouraging employees to turn their engines off when parked has further reducing emissions. He said employees are taking environmental lessons home from work and reducing idling in their personal vehicles. Others are taking advantage of Kennecott programs incentivizing the use of mass transit to get to work, he said.
With only 3.5 percent of emissions coming from its mining operations, Kennecott’s greatest contribution to air pollution in Salt Lake County may come from the tens of thousands of residents the company hopes to attract to its 20,000-unit Daybreak housing development. But even here, Kennecott is actively trying to get out in front of environmentalist critics by committing itself to strict energy efficiency standards and advocacy of public transit. All of the homes in Daybreak are ENERGY STAR rated and Kennecott is largely responsible for bringing light rail to the southwest corner of the valley, Bennett said.
“We have consistently seen regulations get stricter and stricter. All of the easy things to accomplish are done. Everyone needs to get involved. It really is a shared responsibility. We’ve got to turn off our engines when we’re dropping our kids off. We’ve got to ride public transportation on red air days,” Bennett said.
“The easy solutions with a big impact are getting harder to find,” he said.