China v. Utah: Whose air is worse?

  • Salt Lake City or Beijing?

    Mark Ralston, AFP, Getty Images
  • Salt Lake City or Beijing?

    Ed Kosmicki
  • Quiz answers:

    Mark Ralston, AFP, Getty Images; Ed Kosmicki
  • High above the smog that blankets Utah's Wasatch Front.

    Ed Kosmicki

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).

Jim Vance
Jim Vance
Feb 19, 2013 05:41 PM
The really big difference between SLC and Beijing (indeed, any city of size which lies north of the Yangtze River) stems from the particulates and other emissions in the exhaust from many widely-dispersed furnaces whose associated boilers produce steam fed into the district heating systems that are the primary means for apartment and office buildings to maintain a reasonably warm interior temperature. Any city which lies to the south of the Yangtze is prohibited by central government decree from construction or operation of such systems.

Where they exist, the furnace-boiler operations utilize the cheapest coal available and most of the equipment is old, not that well-maintained and operates with relatively low combustion efficiency. In combination with the much shorter exhaust stacks (short by comparison with power generation plants' tall stacks) and complete lack of any emissions control technology, the exhaust mix produced by these many small furnaces is easily trapped in close proximity to the ground by air inversions which are common during cold winter months and combines with motor vehicle exhaust to produce a much more toxic mix than any city in the US ever experiences.
Mike Welch
Mike Welch Subscriber
Feb 19, 2013 06:55 PM
Not to make any excuses for the atrocious smog seen in SLC, but the REAL difference between places like SLC and Beijing (or even between SLC and Los Angeles) is that SLC experiences terrible air quality for really only about (1) month out of the year---that month being January. Sure, there are poor air quality days here and there in other months, but for the VAST majority of the days and months and year, SLC's air is as crisp and clean as the Rocky Mountains that loom high over the city. Now, Beijing on the other hand...
Lyn McCormick
Lyn McCormick
Feb 19, 2013 07:03 PM
Does anyone know if the ozone study by NOAA in the Uintah Basin (referenced in the sidebar of this article) was completed and if so, what was the outcome ?
Evan Dillon
Evan Dillon
Feb 19, 2013 09:49 PM
Real-time air quality for Utah is available here:
Jonathan Thompson
Jonathan Thompson Subscriber
Feb 20, 2013 07:16 AM
Evan: Thanks for the link!
Lyn: Yes, the study was just released days ago, in fact, and finds that (surprise!) oil and gas are the main cause of the ozone pollution in the Uintah Basin. Here's the link to the study: