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Know the West

China v. Utah: Whose air is worse?


Quiz: Utah's Wasatch Front or Beijing?

1. Which area had the worst air quality in its respective nation during January 2013?

2. Which place prepared for hosting the Olympic games by expanding the public transit network?

3. Which region has real-time air quality data, frequently updated on Twitter?

For answers, see the bottom of this page.

Beijing? Or Utah's Wasatch Front? This winter it's been hard to tell the difference, since the air in both places has been so thick with pollution that you can't tell if you're looking at the Mormon Tabernacle or the Great Hall of the People. On Jan. 23, Provo, Utah's air-quality index hit 190, meaning there were about 130 micrograms of tiny particulates in every cubic meter of air, nearly four times the national ambient air quality standard. (Beijing is much worse, with an AQI sometimes exceeding 500.)

The phenomenon in Utah is caused, first, by particulates spewed into the air by cars, airplanes, wood-burning stoves and a host of industrial sources, including Kennecott mining and smelting operations and a couple of refineries. Then it's trapped by a temperature inversion.

Typically, temperature drops as altitude increases and warm air rises, taking pollution with it. However, during winter days with high barometric pressure, the pattern can be inverted, so that the temperature near the ground is colder than it is up high, creating a "cold air pool" in the Salt Lake Valley and neighboring Utah Valley. At the peak of this year's "mother of all inversions," as University of Utah Atmospheric Sciences Professor Jim Steenburgh called it on his "Wasatch Weather Weenies" blog, the temperature at 7,000 feet of elevation was 40 degrees warmer than it was on the valley floor, 3,000 feet below. That trapped all that nasty smog in the valleys for several days, slashing visibility and making breathing a dangerous pursuit.

Quiz Answers: 1. Both; 2. Both; 3. Beijing (the Wasatch Front has limited air-quality monitors, and a Twitter feed is updated just once per day).