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Researches use TRAX for more than commuting

A team of U researchers has launched an air pollution monitoring project using TRAX that will result in a better understanding of air pollution across the Wasatch Front.

Utah researchers Logan Mitchell, Erik Crosman, John Horel, and John Lin from the University of Utah’s Department of Atmospheric Sciences are a few months into an ongoing project, in which data are being gathered from sensors mounted on TRAX trains, in coordination with several partners in the community. Click here for more details.

Lin explains the project in a Q&A with @TheU.

Describe the TRAX project. What are you studying? 

The project seeks to measure pollutants (PM2.5, ozone), greenhouse gases and meteorology using instruments installed on the Utah Transit Authority’s light rail train (TRAX) that travels through the Salt Lake Valley.  These measurements take place continuously, yielding a detailed look at how pollutants vary around the clock as well as fine spatial detail when the train is operating from the early morning to late in the evening.  As far as I am aware of, these measurements are quite unique–the Salt Lake area is one of only a few urban regions in the entire world that have environmental sensors onboard a light rail car.

What do you hope to discover?  How could this tie-in to the broader debate of air quality issues in Utah?

The combination of the fact that (a) the TRAX system crisscrosses the Salt Lake Valley regularly, from north to south, east to west and (b) the measurements are continuous, automated, and require only occasional human maintenance means that the TRAX-based measurements provide a level of detail about pollutant distributions that is difficult to obtain by other means.  Through these unique observations, we hope to characterize how pollutants are distributed in different parts of Salt Lake Valley, at various times of the day, with fine granularity.  Then we seek to understand the emission patterns, meteorological processes, and chemical phenomena that explain the observed pollutant distributions.  These TRAX-based measurements, in combination with other environmental data, could be used by health researchers in the future to help understand the variability of exposure to pollutants for Salt Lake Valley residents. I should point out, however, that due to the preliminary nature of these measurements, we are just starting to understand how to interpret the information we are obtaining.

You have several students who are a part of the project, which is unique because of Utah’s landscape. How does student participation on the project help advance the research, and why does the University of Utah offer such a special laboratory for this particular subject matter?

Students at the graduate (Alex Jacques) and undergraduate (Ben Fasoli, Luke Leclair-Marzolf, Nate Larsen) levels in the Department of Atmospheric Sciences have been critical members of the project.  The students have been engaged in almost all aspects of the project, from installing the instruments, designing the system to store and transmit the data in real time, to analyzing the data and displaying them on a website.  This was possible at the University of Utah because of the fantastic training the students received, in both atmospheric science theory as well as hands-on skills in computer programming and environmental instrumentation.  Furthermore, the collaborative environment at the University of Utah has made the project a real success:  the project was a close collaboration among the Land-Atmosphere Interactions Research (LAIR) group (, the MesoWest group ( and the Global Change and Sustainability Center (  The spirit of cooperation extends beyond the campus: the collaboration among the U, the Utah Transit Authority (UTA) and the Utah Division of Air Quality (DAQ) has been absolutely essential for this project.