Stuart Johnson, Deseret News
Part of Ensign Peak, at right foreground, pops up above the a layer of fog and smog as an inversion camps out over the Salt Lake Valley on Wednesday, Dec. 13, 2017. In the distance at left is Antelope Island.

The smothering blanket of gloom brought by the current weather pattern brings forth the prospect of a not-so-white Christmas, along with an elevated discussion about what the upcoming session of the Utah Legislature might do in the way of improving overall air quality. Despite the hazards and discomforts of the winter inversion season, we are optimistic about trends that suggest progress is slowly being made in the way of cleaner air.

For perspective, overall air quality in the valleys of northern Utah has improved slightly but steadily over the past several decades, despite rapid population growth and exponential increases in the number of automobiles on the roadways. The EPA reports that Salt Lake City’s average Air Quality Index, a measure based on the number of pollutants in the air, fell nearly 96 points between 1980 and 2014.

There has also been increased investment in mass transit, in better air quality monitoring and in programs aimed at bringing down levels of particulate pollution tied to factory smokestacks, refinery towers and automobile tail pipes. Yet, much remains to be done in a process that will bring improvement only incrementally.

For those striving in the private and public sectors for better air quality, lingering winter inversions present the worst possible optics. They are depressing real-time reminders of a problem that negatively affects both physical and mental health. On an average of 14 to 30 days a year, cold air will get trapped on valley floors under a ridge of high pressure, and breathing air becomes increasingly toxic.

Inversions are largely why the Salt Lake City metro area annually makes the top-10 list of cities with the worst short-term particulate pollution. But Salt Lake City ranks 80th among metropolitan areas in the category of year-round particulate pollution, according to the American Lung Association’s annual State of the Air report. By that 365-day measure, Salt Lake City has healthier air year-round than San Francisco, Cincinnati, Pittsburgh, Indianapolis and even Fairbanks, Alaska. Were it not for periods of inversion, Utah’s cities would likely not suffer from the “among the most polluted” stigma.

But if inversion periods end up promoting more public awareness and increased action on the policy level, there’s at least a little silver in the dank gray lining over the mountain valleys. When it comes to policy, there are currently some positive signs, and others that are worrisome. On the positive side, Gov. Gary Herbert’s recently proposed budget includes an initiative to free up the state’s $600 million transportation fund to invest more in mass transit. In Salt Lake City, a new transportation master plan ambitiously seeks to eventually put a mass transit stop much closer to every resident, with more frequent service.

Taking cars off the road is perhaps the most effective means of bringing down levels of pollution, given that auto emissions account for 57 percent of the particulate count. On that score, it is troubling to see the Trump administration considering a rollback of some regulations governing vehicle emissions. Federal standards for clean burning gasoline and more efficient engines have brought pollution levels down dramatically.

There will be several measures related to air quality up for debate on Capitol Hill when the Legislature convenes in coming weeks. Based on recent history, we are hopeful that thoughtful and effective policy measures will result, continuing a trend toward improvement that is hard to recognize when an inversion surrounds us with a gauzy shroud of unsavory air.