University of Utah scientists are using an unlikely tool to collect groundbreaking data about air pollution – TRAX.

In 2014, scientists installed an air quality monitor on a single TRAX car. Last year, another monitor was installed on a second car. As the TRAX cars travel on the Red and Green lines, monitors measure air pollutants like ozone, particulates, dust and greenhouse gases. The data is then used to help study factors like pollution patterns and hotspots.

“It gives us a new way of looking at things,” said University of Utah Department of Atmospheric Science Research Assistant Professor, Erik Crosman. “We’re seeing pollution in the valley as a fluid mass, ever-changing and more complex than we could have guessed. It’s provided us with proof for some hypotheses that we never would have expected.” 

In many ways, Crosman said, TRAX is the perfect vehicle for the monitors. Data can be collected across the valley, day and night, at different altitudes and in cities as well as suburbs. Unlike cars, TRAX trains are powered by electricity and don’t release emissions that could distort the air quality data. The project has been so successful that it has been presented at global scientific conferences and other cities are considering following suit.

The project has resulted in some unexpected findings, Crosman said. Scientists have discovered that canyons along the Wasatch Front act as clean air tributaries, pushing fresh air into the valley. Another surprise, he said, is that although the University of Utah sits on the east bench and escapes some of the winter inversion, it has higher levels of summer ozone pollution than other valley locales.

Crosman said that he and University of Utah Post-doctoral Researcher Logan Mitchell plan to continue the study, if funding remains available for staffing and equipment maintenance. Eventually, they hope to see monitors placed on more trains and possibly electric buses.

The monitors are currently located on top of TRAX cars 1136 and 1104. Although they’re not visible to riders, when you ride in those cars, know that you’re taking part in a unique scientific study to help improve Utah’s air.