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Standard Deviations: There’s just no crawling under our winter inversions

By Mark Saal - | Oct 4, 2016

Whenever something would go south in our family, my father had an old line he liked to use.

“Well, you know what they say,” he’d intone with a sad smile. “The rich get richer, and the poor get pregnant.”

Ah, but as it turns out, that’s not all the poor get. Apparently, they also get lung cancer, bronchitis and asthma.

Permit me to explain.

So, last year, during one of those murky temperature inversions along the Wasatch Front, I found myself up high on Ogden’s east bench, looking out over a thick layer of pollution stretching across the valley. As I stood there, the thickest part of the haze was at eye level while closer to the ground it appeared a bit clearer.

It got me to thinking. One of the few safety lectures I remember from my childhood was being taught that if I ever woke to the smell of smoke, I should crawl out of the room. Smoke, I was told, rises toward the ceiling, so the air is better closer to the floor. (The other safety lecture I remember: “Never accept candy from strangers, unless it’s Oct. 31.”)

Standing there, looking at that layer of haze hanging just above the valley floor, I had an epiphany: Maybe temperature inversions are like smoke-filled buildings. Maybe the better air is closer to the ground.

As I gazed around at the trophy homes perched high on the east bench, I recall reasoning, “Well, at least the huddled masses crawling around down on the valley floor are breathing a little easier than the high and mighty standing upon their elevated locations.”

That comforting thought sustained me through many a depressing inversion that winter.

Boy, was I ever wrong.

With the new diesel emissions testing program in Weber County — and winter just around the corner — I thought I ought to at least get some facts to back up my hypothesis. So I called up the Program for Air Quality, Health, and Society at the University of Utah, and shared my theory with Kerry Kelly, an assistant professor of chemical engineering.

Funny you should ask, Kelly told me. She just happened to be involved in a study several years ago at the university, wherein they examined that very thing. Their conclusion?

“It is better to be higher up,” she said. “Because the inversion starts lower in the valley, and it builds. And so, the higher up you live, the later you get into the inversion, and the sooner you get out of it.”

What’s more, apparently the pollutants during an inversion act a little like water in a dish.

“The inversion actually kind of sloshes around the valley during the day, and so you’ll end up out of the inversion a little bit as it sloshes around,” Kelly said.

Even healthier than living along the benches of the Wasatch Front, according to Kelly, would be living in Park City — although she doesn’t recommend a change.

“It is better in Park City,” she said. “But I’m reluctant to tell people to move to Park City because then they end up driving more — which is a major contributor to poor air quality.”

But what about the pollution we see during the summer? Is it better to live at higher or lower elevations when it’s warm out? For that, we turn to the department of atmospheric sciences at the university.

Kevin Perry is an associate professor and the chairman of the department. Surely he knows if it’s better to live in the mountains or the valleys during the summer.

“The short answer is … we don’t know the answer,” Perry said.

In the summer, pollution comes from a lot of different sources, according to Perry. There are local sources, like vehicle emissions. But there are also regional sources, like wildfires. With wildfires, the pollution will probably come in at a higher altitude, he said.

“In situations like that, the air quality up at, like, Alta or Snowbird may be temporarily worse than it is down in the valley,” Perry said.

Compounding the breathing problems in the summer are various plumes of dust — from local sources, such as the Great Salt Lake or the Kennecott tailings pile; regional sources, like the Sevier dry lake; and intercontinental sources, such as China.

“If a place is being dominated by local sources, the closer you are to those sources the worse the air quality’s going to be,” he said. “But if it’s dominated by these regional air sources, then it could be flipped. You could have worse air quality at higher altitudes.”

As you can see, predicting the impact of air pollution is much more difficult during the warmer months.

“Wintertime’s easy,” Perry said. “The lower you are, the worse it is. But summer is more complicated.”

Of course, if it makes you feel any better, Kelly points out that even in the heart of one of these soupy winter inversions, whether you live on the bench or in the valley doesn’t make much difference.

“It isn’t an enormous effect,” she says. “But it is an effect.”

In other words: The rich only get a little bit richer, and the poor only get a tiny bit pregnant.

Contact Mark Saal at 801-625-4272, or msaal@standard.net. Follow him on Twitter at @Saalman. Like him on Facebook at facebook.com/SEMarkSaal.


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