8 things you should know about Utah's air inversions

Saturday , January 24, 2015 - 8:30 AM

For 15 years, the state of Utah has collected information on particulates polluting the air during inversions. The travel-trailer sized monitors quietly collect ambient air data at stations throughout the state, particularly in areas known for cold pool air and high levels of accumulating particulate.

The arguably underfunded Division of Air Quality gathers and analyzes the stations’ air quality data daily, partly in the name of public health and partly to appease regulation handed down by the federal government.

Year after year, our state fails to comply. Almost every year, we ring in another year with another inversion and its gloomy, unhealthy air.

On the plus side, the data has tracked our human progress on curbing pollution that collects as part of the natural metrological phenomenon. Still, it also reveals gaps where our state-specific knowledge remains hazy.

1. It’s a different issue from global warming.

Global warming, also called climate change, has to do with greenhouse gases like carbon dioxide and carbon monoxide building up in the atmosphere. Those gases hold in more radiation from the sun, leading to a warmer planet. Inversion pollution comes from air particulate, not gases.

“As we’re focused on solving our problems, what we’re focused on is the wintertime pollution trapped under our inversions,” said Bryce Bird, director of DAQ. “What causes that is the fine particulate matter.”

When it comes to air pollution, the Environmental Protection Agency requires states to pay particular attention to particulate matter that’s 2.5 micrometers and smaller, or PM 2.5. Around 30 PM 2.5 could fit within the width of a human hair, and that’s the problem.

“The smaller bits get down into your lungs,” said Bo Call, DAQ’s air monitoring section manager. “It’s particulate that causes the problem.”

2. Most of the gunk in inversion air is formed after cooking in a chemistry soup.

Some of our air pollution particulates are formed directly, like tiny metals blowing out of smoke stacks or dust from tires getting eroded by freeways. Most of our particulate pollution, however, is formed secondarily after compounds cook in the atmosphere.

Along the Wasatch Front and in Cache Valley, the mountains act like a bowl. That bowl collects a mixture of particles and volatile organic compounds. The mixture acts like a chemistry soup, cooked by sunlight, creating particles that cloud the air and cause breathing problems.

“The end result is … a solid particle, and we can measure it on the filter,” Call said. “In the winter, they might not form as easily or readily. That’s why we have a winter problem.”

According to DAQ information, around 75 percent of our inversion pollution is formed this way.

3. Our inversion air quality has improved over time.

Even with a growing population on the Wasatch Front, the amount of PM 2.5 during inversion seasons has gotten better over the past 15 years.

DAQ has collected PM 2.5 data at monitoring stations throughout the state since 2000, when EPA air pollution regulations went into effect. According to that information, for counties in the Top of Utah, the annual mean of our PM 2.5 has gone down significantly. In Ogden, annual PM 2.5 levels have dropped by 36.5 percent from 2000 to 2013.

The days when Top of Utah counties exceeded EPA standards for air quality — which usually accounts for the thick, nasty inversion days — have mostly dropped as well. In Ogden, 13 percent of monitored days had air dirty enough to exceed standards. By 2013, only 8 percent of monitored days were above the standard.

Those improvements came with tighter controls on emissions from cars and industry. Weather, however, always throws a wildcard. Even with significant improvements for three years from 2009 to 2011, a strong cold front in 2013 trapped air and made for one of the worst inversion seasons in a decade.

“Inversions are natural; they’re going to come and go just based on meteorology,” Bird said. “What we’re focused on is the concentration of pollutants; that’s what we can do something about.”

Even with air improvements over time, Tim Wagner with Utah Physicians for a Healthy Environment said it doesn’t mean we should stop worrying about emissions.

“Even if they aren’t as bad as they used to be, they’re still bad, and they’re still bad for your health … there is no level of safe air pollution, period,” he said. “This is a daunting problem; it’s never going to go away, but we can make it better. We have to keep working hard.”

4. Public interest in the inversion has also grown over time.

In 2007, both Utah Physicians for a Healthy Environment and Utah Moms for Clean Air formed to lobby the state Legislature and grow the public conversation on health issues associated with inversion pollution.

“It’s not a small thing when parents ask for kids to be held in at recess because the air is so bad,” said Ingrid Griffee with Utah Moms for Clean Air. “To me, that’s entirely unacceptable. No family should have to fear for their children playing outdoors.”

In 2013, DAQ worked with Weber State University to develop a cell phone app, meaning real-time air quality information was available at Utah residents’ fingertips. Griffee said she has also seen growing awareness and media coverage of the pollution problem.

“I’ve been really excited to see coverage recently talking about how, right before a pollution episode setting up, there’s a lot of publicity saying ‘we’re heading into an inversion so let’s prepare for this,’” she said. “We can’t control weather, but we can control pollution we put in the air.”

Last year the two interest groups, along with the Sierra Club and HEAL Utah, helped organize the “Clean Air – No Excuses” rally on the steps of the Utah Capitol in Salt Lake City. Around 5,000 people attended. This year, they’re trying to double that number during a rally set for Jan. 31 at noon.

“Already awareness of this is growing and growing,” Griffee said.

5. Sources of particulate pollution vary by season.

One of Ogden City’s worst days for particulate pollution isn’t in the winter. Accordingly to DAQ data, it’s often on July 4.

“There’s a lot of PM 2.5 from fireworks,” Call said. “The metals that make them boom and give them sparkly colors, we know their residues and residuals. They show up on our filters, so we can say ‘oh yeah, this is fireworks.’”

The difference is, there aren’t usually inversions in July so the air in the atmosphere mixes and helps clear out the gunk.

Those seasonal mixes have a major influence in the state’s air quality. Based on DAQ numbers, the vast majority of northern Utah’s annual PM 2.5 comes from “area sources,” or a broad category of areas without a specific point spewing particulate.

“Area sources are anything within a fence line combined together,” Call said.

In the summer, those area sources include things like dust billowing from dirt roads, plowed fields and construction sites. Those area-sourced particles tend to drop in colder months, however, when the ground is frozen.

Summer is also wildfire season, which can lead to heavy levels of particulate pollution. During the summertime, plants also naturally give off a lot of the volatile organic compounds that can mix in the atmosphere to become particulate matter. In the winter, however, wildfires typically stop burning and plants mostly go dormant.

Winter also brings the cold spells and atmospheric pressure systems that put a lid on the valleys and cause inversions. That stagnant air means particulates don’t mix out. Instead, they hover low in the valleys where most of us live.

“When we develop a plan for a certain pollutant like PM 2.5, we focus on days we have inversions,” Bird said, “so we’re able to look at what’s happening on a typical winter weekday.”

6. The bulk of wintertime inversion pollution comes from cars and broad area sources, not from smokestacks.

DAQ’s state implementation plan, or SIP, closely evaluated sources of pollution during winter inversions in the Salt Lake non-attainment area, which includes Box Elder, Weber and Davis counties.

“Sources basically come down to cars and cows; that’s pretty much what it is,” Call said.

Mobile sources, or cars on roads, account for around 44 percent of PM 2.5 during winter inversions, according to the SIP. Area sources from activities like wood burning, feedlots and vapors escaping from gas stations account for around 30 percent of particulate pollution. Point sources, or particles coming from smokestacks, account for 20 percent.

Still, industry can have significant local impacts to air quality. Emissions from point sources are more abundant near the refineries clustered in Davis and Salt Lake counties, for example. Small particles like PM 2.5 can travel long distances in the atmosphere, Call said, but during an inversion situation the air isn’t mixing.

“One of the problems, with that lid on, all pollution we create tends to build and build until it can all flow out,” he said. “Most of it, during an inversion, is almost certainly homegrown.”

When air sits stagnant, area sources of pollution can have health impacts as well, like wood smoke.

“If you have any kind of respiratory ailment at all, like temporary pneumonia or lifelong asthma, you don’t want to be exposed to any smoke,” Wagner said. “If you have a neighbor that burns smoke all the time, that smoke will get into your home and impact you significantly … it pits neighbor against neighbor.”

7. Even when it’s clear out, inversion pollution might still be accumulating.

While it’s still tricky to predict how much snow is going to fall or if a thunderstorm will roll in, scientists at DAQ have fine-tuned their predictions of when an inversion is building. They can use that information to send out public alerts to start carpooling and curbing wood burning.

Unfortunately, there still isn’t good information on how long an inversion will last. Even when it rains and helps mix up particles in the air, the atmospheric pressure might still be in place that keeps local pollution from escaping.

“It will rain or snow, or the wind will blow, and the next day the air is clear. People say I should be able to burn, because it’s not inverted,” Call said. “Well, an inversion happens when high pressure builds up, not when it looks yucky.”

8. To fully understand our complex inversion issue, we need more Utah-specific studies.

While researchers know particulate matter is bad for health, there’s little specific information on the harmfulness of Utah’s particular air blend. Questions remain on whether PM 2.5 is even the best way to monitor air quality.

“We know it takes money to do good research, and a lot of federal research money has been spent in California and the East Coast,” Bird said at a recent air quality workshop.

The EPA uses that research to develop its federal air quality standards, which are up to the states to implement and enforce. According to Bird, however, it’s hard to know if that data is applicable to Utah, with its low humidity, high elevations and inversions. 

“This needs to be a science-driven process, but also under that (federal) structure we have deadlines,” Bird said. “So we have to make a decision before we have all the information.”

Last year, the Utah Legislature granted DAQ one-time funding of $1 million to collect more state-specific information. Bird said his division received 40 study proposals looking at emissions, summer ozone, health or air quality in the Uinta Basin. They ranked and selected 12 projects.

“That’s when the money ran out,” Bird said.

The studies will help DAQ better understand several Utah air variables. For example, current DAQ monitoring stations are big, bulky and stationary. They only measure air and pollution at specific locations and specific elevations. A portable monitoring trailer will provide more flexibility, and a study at Weber State will use a weather ballon to get a vertical profile of pollution in the atmosphere. Another study will explore the role of the Great Salt Lake in forming ozone pollution, then pushing it to surrounding communities. Another will explore the true impacts associated with idling vehicles and cold starts in Utah-specific conditions.

“We have had to rely on national information and try to apply it to Utah,” Bird said. “With the funding we received last year we were able to focus on Utah-specific questions. We’ve got good results, but it also brings up more questions we need to address as well.”

Bottom line, Bird said, “there needs to be ongoing funding.”

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