STI worked with the Sierra Club to conduct air quality modeling and estimate the impacts of power plant emissions on ozone concentrations in downwind states. Multiple Midwestern and Eastern states, impacted by ozone emissions from upwind neighboring states, needed this modeling analysis to support their filing of regulatory petitions under the U.S. Clean Air Act.
Using the CAMx model, STI tagged over 150 individual electrical generating units (EGUs), groups of EGUs, or EGUs over a geographic region so that the model could quantify their contributions to downwind ozone concentrations. STI then used EPA post-processing methods and developed a database containing the ozone impact results from each tagged source.