For decades the United States has benefitted from air pollution protections backed by science. From ambient air quality standards to industrial emission controls to climate mitigation efforts, many federal policies are required to protect public health. Yet, recent efforts to change science and process at the US Environmental Protection Agency now threaten the longstanding role of science in federal air pollution and climate policy development. Science advice has diminished, data collection has declined, science-informed policy processes have been upended. Other proposals may restrict the kinds of science that can inform policy decisions in the first place. Focusing on EPA policy developments in recent years, this session will examine the implications of proposed and actual changes to how the country approaches air quality and climate protections and offer ways researchers and decisionmakers can ensure science informs US air pollution and climate policy.