Solving the Wasatch Front's winter smog just got harder at least on paper.
That's because updated number-crunching shows that the clean-air fixes regulators already have proposed won't do as much as originally expected for the spikes of PM2.5, which sometime shrouds northern Utah in a brown fog for weeks at a time in winter.
In fact, Utah County needs to cut its wintertime pollution by another 20 percent, and a five-county area around the Salt Lake Valley needs to reduce emissions by 10 percent more to meet the U.S. Environmental Protection Agency's health-based standards.
And that's on top of tons and tons of pollution that's already averted in the Utah Division of Air Quality's six-year plan.
"As you can see," said the air-quality division's PM2.5 guru, Bill Reiss, "we still have a ways to go."
The state's scientists and engineers have been working for three years to meet the EPA's limits for episodes of PM2.5 microscopic soot from exhaust that mixes with other pollutants to make even more pollution that gets trapped in Utah's mountain basins during periods of high atmospheric pressure.
The pollution causes health problems, which range from the irritating scratchy eyes and throats to the dangerous attacks that send asthmatics to hospitals and trigger premature death from heart and lung conditions.
And it was bad enough last winter to prompt three rallies on Utah's Capitol Hill during the inversion-choked legislative session and to garner "F" grades from the American Lung Association.
New data revealed Wednesday showed that, in order to reach the EPA's 2019 target level of 52 tons of pollution on a typical winter day, Utah County will have to cut another 10 tons of emissions. And the Salt Lake County area, which also includes parts of Box Elder, Tooele, Davis and Weber counties, will have to find a way to eliminate another 22 tons of pollution to reach a 227-ton target.
That's twice more than was expected in Utah County and nearly five times as much in the five-county area compared with the estimates air-quality officials tallied in December, when plans were originally due at the EPA.
The reason the estimates are so different is the computer model EPA is requiring state regulators to use is not well-suited to Utah's unusual pollution profile and also because the state has had time since December to add more data to the computer calculations, as the EPA has required.
Dave McNeill, who oversees the state's pollution-plan effort, told the Air Quality Board on Wednesday that the easy pollution cuts from industrial smokestacks were made a long time ago, and now the state is making an unprecedented effort to reduce emissions from everyday activities and from vehicles, which account for around 57 percent of the state's winter pollution problem.
Regulators already have imposed restrictions on exhaust from grills and fumes from auto-body shops. New standards are even in place for the pollution released by consumer products like window spray and hair spray.
And everyone is affected, McNeill said.
"We've done almost everything we can do, and we need more a lot more."