Frequently Asked Questions:
Statewide Emissions Inventory Program

What is the difference between air monitoring data and emissions inventory data?

Air monitoring data shows current air pollution levels collected from 23 monitoring stations throughout the state, while emissions inventory data is a summary of pollutants released in Utah throughout the year. Air monitoring data is expressed as a concentration, such as µg/m3 (micrograms of pollutant per cubic meter of air) or ppm (parts per million), whereas emissions inventory data is expressed as tons/year.

Because the units of measurement are different, it is challenging to compare the two data sets; this means it is difficult to compare what we think should be in the air (inventory) to what is actually in the air (monitoring). While there is currently not a comprehensive comparison of the two data sets, in specific situations, the division’s air modeling team runs inventory data through complex computer models to simulate how it would look in real time.