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Know the West

EPA releases a stricter, health-based smog standard

Failure to meet the new requirements can trigger serious economic consequences for some communities.


When atmospheric scientist Dan Jaffe talks to his students about the tighter smog standard released today by the Environmental Protection Agency, he calls it the “make work for atmospheric scientists standard.” Many areas in the Intermountain West measure smog levels that exceed the new health-based standard of 70 parts per billion,  even rural areas without any big local pollution sources. States will need to recruit atmospheric scientists to figure out whether conditions beyond states’ control were to blame.

Air quality on Mt. Bachelor and other unexpected places in the Intermountain West exceeds the new ozone standard.
Courtesy Stan Shebs
In the West, a variety of sources can contribute to elevated ozone levels — forest fires, pollution from abroad or ozone that storms push down from the stratosphere, six to 30 miles above Earth’s surface. Up until now, Western states, besides California, haven’t had to pay much attention to teasing out the sources of ozone. They generally met the standard. But that will change dramatically under the new health-based standard, according to scientists and regulators.

“The lower the standard gets, these so-called exceptional events aren’t going to be exceptional any more,” says Andrew Langford, an atmospheric scientist with the National Oceanic and Atmospheric Administration.  “Stratospheric contribution and Asian pollution contribution are not very significant in the northeast and southeast, but they’re really big in the West, particularly the Intermountain West.”

The source of the pollution matters because under EPA rules, the agency can excuse high ozone days if they were caused by a wildfire, dirty air from Asia or Mexico or a storm that delivered stratospheric ozone into a community. However, if the smog came from a U.S. anthropogenic source, even another state like California, intermountain states will not be off the hook.

This is important to states and communities because failure to meet the standard can trigger serious economic consequences. For instance, in communities that exceed EPA air quality standards, new industrial facilities must install pollution controls, which can be expensive and deter companies from building their factories or even hospitals in those communities.

Some of the places likely to find the new standard challenging are in rural Utah. Monitors in Zion and Great Basin National Parks have detected high enough ozone levels that nearby rural communities and the small city of St. George may end up exceeding the new standard, according to Bryce Bird, air quality director at the Utah Department of Environmental Quality.

Utah could try to make the case that the elevated ozone levels in these counties were the result of causes beyond the state’s control — such as wildfires, stratospheric ozone or dirty air in Asia. But each time, the states would have to deliver detailed reports to the EPA making that case.

“Air pollution research costs lots of money. It’s something that’s not funded by the EPA, and states would have to bear those costs,” Bird complains.

Bird says Utah and other Western states have communicated their concerns to the EPA. “I don’t mind spending resources to improve air quality but to expend resources to have air quality stay the same I don’t think is the best use of our funds,” Bird adds.

Scientists agreed that at least under current EPA rules and procedures, states are in for a lot of hassle.

“What is problematic for them is the amount of work it takes,” agreed Jaffe, a University of Washington atmospheric scientist. That’s why the new standard is good news for his students. “It absolutely is going to require the states to hire more people to understand what’s going on. It takes a pretty substantial scientific case to prove.”

It’s too early to say which areas will be designated as not meeting the standard, which is known as nonattainment. The EPA plans to make those decisions in 2017, based on the average of the 4th highest 8-hour ozone level in each of the previous three years.

EPA maps show large areas in Colorado, Nevada, Utah, Arizona and New Mexico as well as California currently measure ozone higher than the new standard.

However, the EPA estimates that because of anticipated improvements in air quality from regulations and proposed regulations, only 14 counties outside of California, including Larimer and Jefferson Counties in Colorado, would be out of attainment in 2025.

Atmospheric scientists say that EPA’s projections seem optimistic and must reflect states in the Intermountain West getting excused for high ozone levels because they were caused by stratospheric ozone or other circumstances beyond states’ control. Otherwise, there is probably no amount of pollution reduction that would bring many high-elevation Western counties below the new ozone standard.

Scanner atop Angel Peak, Nevada, where ozone levels frequently exceed the new standard.
A. Langford/NOAA

For example, Langford studied ozone in Clark County, Nevada over 43 days in the spring and early summer of 2013. That’s the time of year when the impact of dirty air from Asia and stratospheric ozone intrusion tends to be highest. Remarkably, ozone levels exceeded the new standard on 14 days. He found that stratospheric ozone played a significant role and pollution from Asia played a smaller role. “Models suggest that this applies across much of the Intermountain West,” Langford adds.

Jaffe has studied the impact of stratospheric ozone over the last ten years at his air monitoring station on Oregon’s Mt. Bachelor at 9,000 feet.  The air there should be pristine but instead it exceeds even the 2008 standard of 75 parts per billion.

“It’s going to throw large parts of the West out of compliance at least on the face of it; this is going to be a very hard standard to meet, a very hard standard for sites at high elevations,” Jaffe said about the new 70 parts per billion standard.

EPA plans to work with states and simplify the process for proving that exceptional events contributed to high ozone levels.  The agency does not expect this to hinder states’ abilities to meet the new standard.

“The Clean Air Act and EPA policies provide a number of tools to help states in the limited number of areas where background ozone may contribute to high ozone concentrations on a few days,” said Enesta Jones, an EPA spokeswoman. “These tools may help areas avoid a nonattainment designation, or minimize attainment control requirements where appreciable levels of background ozone influence air quality.”

Elizabeth Shogren is HCN's DC Correspondent.