"We're living in an unhealthy, horrible place," said Waters, noting that the beautiful landscape and vistas are among the state's most prized qualities.

A Salt Lake City marketing adviser, she escaped a few times to the clear, clean skies in Park City to give her lungs a break. But she knows jaunts out of the valley don't solve the bigger problem of breathing air so sooty day in and day out that being in any other U.S. city was more healthy than being in Salt Lake City, Provo, Ogden or Logan for several days last month.

For Waters and other Wasatch Front residents, air-quality experts have both bad news and good about Utah's wintertime pollution.

The good news? Overall, we have less pollution than we used to.

"Even though we may not have known how bad it was [for our health] in the past," said Bill Reiss of the state Division of Air Quality, "it was worse."

The bad news? January's episode was pretty bad. And, with the knowledge gained about the many, troubling health impacts of microscopic soot, concern is bound to increase as more cars, more homes and more industry add to the pollution.

Waters cannot remember seeing Utah as bad as it was last month even though she grew up here.

But many people can remember breath-choking inversions or have heard stories about them.

Before white settlers arrived in the Salt Lake Valley more than 150 years ago, American Indians called it Smoky Valley.

Even Gordon B. Hinckley, president of The Church of Jesus Christ of Latter-day Saints, has recalled how, when he was a boy, his family had a yearly spring ritual of washing the coal grime from walls of their Salt Lake City home.

And, there have been times since when drivers had so much soot on their car windows, they needed to use their windshield wipers to see the road ahead.

This anecdotal evidence of severe inversions is all scientists have to go on to say the air quality could sometimes be awful. Until the new environmental laws of the 1970s including the creation of the U.S. Environmental Protection Agency and the Clean Air Act, scientific data on pollution wasn't collected.

At first researchers only looked at TSP, or "total suspended particles," that included all the dust and soot in the air. In 1987, monitoring changed to look at "particulate matter 10," or PM10, particles about one-tenth the width of a human hair. Monitoring for the smaller, more dangerous PM2.5 particles, about one-fortieth the size of a human hair, only began in 1999.

Still, based on the PM10 data, it is possible to get an approximate picture of what PM2.5 levels were like in Utah since the mid-1980s. And the picture isn't very pretty.

In Salt Lake County, for instance, four monitors - at Cottonwood High School, Hawthorne Elementary, North Salt Lake and the old air monitoring center at Interstate 15 and 400 South - showed pollution levels comparable to or worse than the highest levels measured in late January.

All of the locations, every year, showed episodes of PM2.5 at least double the current allowable levels, and numerous readings over four years showed levels four times EPA's current "unhealthful" trigger for the pollutant.

Many changes have helped improve the air, even while the state's population and vehicle fleet have grown dramatically.

Geneva Steel and Kennecott Copper updated their plants, and Geneva eventually shut down for good. Pollution checks became a requirement for vehicles in four Utah counties. Power companies and industry switched fuels from coal to cleaner-burning natural gas. And new cars and trucks began replacing older, higher-pollution models.

In fact, state data gathered over the past six years show PM2.5 holding steady just below the national annual standard for PM2.5, an annual average of 15 micrograms per cubic meter of air.

While air-quality officials welcome the improvements, they hesitate to declare victory, especially because the growing evidence is that even smaller amounts of PM2.5 cause health damage.

Arden Pope, a Brigham Young University economist, helped author some of the early studies that identified the dangers of PM2.5. While today's numbers may be lower compared with those from 15 years ago, they still are troubling, said Pope and many others. The reason is that thousands of studies in the past decade have shown the serious effects fine-particles can have on health.

Just last week, a study in the New England Journal of Medicine suggested that PM2.5 pollution elevates the risk of dying of heart disease by 76 percent in older women. The risk of living year-round in high-pollution areas is comparable to living with a cigarette smoker and possibly even smoking, according to the study.

"Our understanding of its effects have improved," said Pope. "And our concern has understandably grown."

The EPA cut its standard for PM2.5 episodes nearly in half last year to 35 micrograms per cubic meter of air- a move that drew criticism even from its own science advisory panel for not being tough enough. Utah air-quality officials are certain that PM2.5 will be so high in Utah from the Idaho border to Juab County that the state will violate the new standard.

That means state officials will be looking hard between now and 2013 at ways to lower pollution. If they fail, the state might be forced to hike fees charged to new and expanding businesses, freeze road-building funds and, if all else fails to get the air cleaned up, to surrender control over air-quality programs to the federal government.

Waters notes that, as measured by the EPA's air-quality index, pollution is often worse in northern Utah valleys than in Denver or Los Angeles.

She blames lax leadership in Utah's Capitol and among regulators. "It's just a joke," she said. "We need to work harder than L.A. has, and we are just doing nothing."

fahys@sltrib.com