Mark Zondlo is a professor of civil and environmental engineering and director of the department’s graduate studies. He is also on the executive committee of the Andlinger Center for Energy and the Environment. His research activities focus on the sources, sinks, and distributions of trace gases important for understanding air quality, the carbon and nitrogen cycles, and climate change. He and researchers in his lab have developed new optical-based sensors to make innovative field measurements as part of large, multi-disciplinary field studies. Other research interests include cloud formation, the role of aerosol particles in atmospheric chemistry and global air pollution and quality. He is a Princeton’s High Meadows Environmental Institute Associated Faculty member and part of the Grand Challenges Program.