Following her PhD research in 2011, Fischer became a NOAA Environmental Fellow at the Harvard University Center for the Environment. There, she "explored the processes controlling the distribution of the most important atmospheric oxidants, the hydroxyl radical and ozone." In 2013, she became an assistant professor at Colorado State University, where she works today and leads the Fischer Group, which focuses on studying the troposphere composition; some of the projects include "Fires to Farms: How do wildfire smoke driven changes in radiation impact crops and solar resources?", "Transformation and Transport of Ammonia (TRANS2AM)", "Leveraging Field-Campaign Networks for Collaborative Change," and many others. Her most notable work was done on the Western Wildfire Experiment for Cloud Chemistry, Aerosol Absorption and Nitrogen (WE-CAN) project. The goal of the project was to study both the chemical make-up and travel of compounds produced by wildfires. Additionally the project pioneered a satellite technique for measuring PAN that now gives scientists a panoramic perspective.