SALT LAKE CITY — A recent study that is one of the first of its kind looked at a dozen major air pollutants and their link to visits to emergency rooms or doctors in five major cities.

Not surprisingly, the study published this month in Environment International found an increased risk of adverse health outcomes given greater exposure to the array of pollution.

The study led by George Mason University's Jenna R. Krall, however, did find secondary pollutants — those formed by chemical reactions in the air — may play a greater role in heart disease or respiratory ailments than most research emphasizes.

In addition to Mason, researchers from Emory University, Georgia Institute of Technology and the University of Pittsburgh looked at levels of 12 pollutants in Atlanta, Dallas, Pittsburgh, St. Louis and Birmingham, Alabama, over a multiple-year period.

The research time frame generally began as early as 2002 and ended in 2008, and involved gaining consent from individual patients to cull through more than 1.8 million billing records.

Researchers looked at air pollution data for primary pollutants and chemical constituents such as sulfate, nitrate and ammonium from ambient monitoring stations within each of the five metropolitan areas.

The key question at the heart of the research asked what happened to people during short-term exposure to these pollutants and if there was an increased risk of medical treatment for asthma, chronic obstructive pulmonary disease, congestive heart failure and others.

Researchers noticed that many previous studies used only a single-pollutant framework.

"Most previous studies of air pollution and cardiorespiratory (emergency department) visits are single-city studies that only examine a few pollutants or a few specific outcomes," the research noted.

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Utah cities ranked with worst air quality in nation during inversion

KSL tracked the EPA's ranking of cities with the worst air quality in the nation for six days, and Utah cities made a prominent appearance three out of the six days during a particularly bad inversion.

This study developed a multicity model that treated each pollutant individually, but did not attempt to identify individual sources of pollution.

They found that across the five cities, the number of days with complete pollution and emergency room visit data varied from 1,096 days in Dallas to 2,557 days in Atlanta.

The study noted the complexity of the research, with its variable outcomes, statistical uncertainty in some instances and its limited, regional scope focusing on the southeast.

Bryce Bird, director of the Utah Division of Air Quality, said he was unaware of any study in Utah that looked at that array of pollutants and any correlation to emergency room visits.

Local research focuses primarily on Utah's chief culprit, PM2.5, as the indicator pollutant, he said.

"For us that would be difficult to tease out. They (other pollutants) do increase in concentration when the lid is on, but we don't see those high concentrations unless we are seeing the PM2.5."

A majority of northern Utah is out of attainment with federal Clean Air standards for PM2.5, which is fine particulate matter. Those pollution particles are 2.5 micrometers or less — 3 percent the diameter of a human hair — and small enough to invade even the smallest airways.

Over the last several years, Utah lawmakers directed money to the state air quality division and university researchers for local studies that probe PM2.5 pollution problems along the Wasatch Front and to arrive at better answers for the ozone problem in eastern Utah.

Bird said while it is difficult to separate what is happening in a Utah inversion as it relates to PM2.5 compared to other pollutants, the southeast U.S. research could be helpful in the future.

"It would help us in the future to identify strategies to improve health as the result of improving air quality, and determining the exact mechanism that is causing harm," he said.

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