Pratt works in atmospheric chemistry. She was appointed to the faculty at the University of Michigan in 2013. She is interested in various chemical reactions that occur in the environment, including those that occur between trace gases, in aqueous solutions and on surfaces. Primary atmospheric particles can originate from natural and human-made sources, which include sea spray, soot and bacteria. These undergo various reactions and can form secondary atmospheric particles, evolving into dynamical chemical mixtures such as aerosols. These particles can take on a variety of different sizes, between 3 nm and 10 µm. Pratt investigates the interactions between trace gases and clouds using mass spectrometry. She is particularly interested in the atmospheric composition of winter environments, for example, in the Polar regions.  The Arctic is undergoing a rapid loss of sea ice.
Pratt makes use of mass spectrometries to various degrees of sensitivity, for examples aerosol time-of-flight mass spectrometry (aerosols of 0.07 – 1.6 µm diameter), chemical ionization mass spectrometry (gases at sub parts per trillion) and ambient ion mass spectrometry. These results are combined with one-dimensional modelling to understand how atmospheric compositions as a function of altitude and time. She looks to establish the feedbacks between human-made emissions, aerosols and the Earth to better predict air quality. In 2018, she started a United States Department of Energy project to use single particle mass spectrometry during the Polar night. These measurements were combined with data collected from aerosol samples on the German icebreaker RV Polarstern.