Dr. Timothy Sullivan holds a BA in history from Stonehill College, Easton, Massachusetts (1972); an MA in biology from Western State College, Gunnison, Colorado (1977); and a PhD in biological sciences from Oregon State University, Corvallis (1983) through an interdisciplinary program that included areas of focus in ecology, zoology, and environmental chemistry. He did his postdoctoral research at the Center for Industrial Research in Oslo, Norway, on surface and groundwater acidification, episodic hydrologic processes, and aluminum biogeochemistry. His expertise includes the effects of air pollution on aquatic and terrestrial resources, watershed analysis, critical loads, ecosystem services, nutrient cycling, aquatic acidbase chemistry, episodic processes controlling surface water chemistry, and environmental assessment. He has been president of E&S Environmental Chemistry, Inc., since 1988 and E&S Environmental Restoration, Inc., since 1996. He has served as project manager or lead author for a wide variety of projects that have synthesized for diverse audiences complex air and water pollution effects science. He was project manager of the effort to draft a scientific summary and Integrated Scientific Assessment (ISA) of the effects of nitrogen and sulfur oxides on terrestrial, transitional, and aquatic ecosystems for the US Environmental Protection Agency (EPA) in support of its review of the National Ambient Air Quality Standards (NAAQS). He was author of the National Acid Precipitation Assessment Program (NAPAP) State of Science and Technology Report on past changes in surface water acid-base chemistry throughout the United States from acidic deposition. He served as project manager for preparation of air quality reviews for national parks throughout California and coauthored similar reviews for the Pacific Northwest and the Rocky Mountain and Great Plains regions. He has summarized air pollution effects at all 272 Inventory and Monitoring national p