A1: The U.S. Clean Air Act and the Science-Policy Interface

In 2020, the U.S. will celebrate the 50th anniversary of the Clean Air Act. This landmark legislation offers a prominent and consequential example of how science and policy have shaped air quality management in the U.S. From acid rain and nitrogen deposition to mercury pollution and carbon standards, connections between scientific research and policymaking have propelled air quality progress in the U.S. over the past four decades, while progress on federal regulations to address climate change has lagged and the fate of mercury policy is uncertain given recent proposals to weaken the Mercury and Air Toxics Standards.

While the details vary from pollutant to pollutant, the science-policy interface in the context of the Clean Air Act tends to follow the general arc of (1) problem identification; (2) skepticism; (3) gradual acceptance of science; (4) debate over solutions; (5) incremental policy-, technology- and market-driven pollution reduction; (5) monitoring of progress; and (6) periodic evaluation of the need for reform. Embedded in this arc of progress are scientists engaged in meticulous investigation that lead to scientific break-throughs that require personal persistence.

In this session we will explore four high-profile science-policy case studies with scientists who together have worked on the front lines of Clean Air Act policy for decades. This session will include case studies on acid rain and nitrogen emissions, mercury pollution, climate and carbon standards and public health and global air quality. In the case studies, each presenter will share an account of the scientific breakthroughs that have been vital to policy progress and how policy-relevant questions drove new scientific insights; describe the progress that has been made in addressing these problems as well as new challenges that have emerged in the past few years; and outline research needed to drive policy advances related to the Clean Air Act and greenhouse gas emissions in particular. They will also share insights on the elements of a productive science-policy interface. To round out the panel, a fifth panelist will provide the perspective of a senior Capitol Hill staffer and share insights on how science has been most helpful to her in her years working on Clean Air Act policy.

For acid rain and nitrogen, Charles Driscoll, University Professor at Syracuse University and investigator of the Hubbard Brook Ecosystem Study where acid rain was first documented in North America, will recount the science-policy story of the scientific studies and battles that led to major reductions in sulfur dioxide and nitrogen oxides emissions in the U.S., lessons learned, and how recovery from acid rain is now being influenced by a changing climate.

For mercury, Elsie Sunderland, Gordon McKay Professor of Environmental Chemistry at the Harvard John A. Paulson School of Engineering and Applied Sciences and former Environmental Protection Agency scientist, will trace the connections between mercury science and policy that drove research questions and informed advances that ultimately led to the Mercury and Air Toxics Standards (MATS). She will also offer insights on how current policy proposals to roll-back MATS do not adequately take scientific advances into consideration. She will conclude with reflections on how her work at the science-policy interface has enriched her research while demanding skills beyond science.

For carbon, Amelia Keyes, Research Associate at Resources for the Future and lead author of a ground-breaking study of power plant carbon standards will share her perspective of how science has informed policy and policy has in turn shaped research questions in the context of the Clean Power Plan and the Affordable Clean Energy rule. She will share her perspective on the benefits and challenges of working at the science-policy interface as an early career professional and how the experience has shaped her career interests.

For public health and global air quality, Susan Anenberg, an Associate Professor of Environmental and Occupational Health and of Global Health at George Washington University, will discuss the impact of air quality of U.S. public health. She will share a specific example of the inter-relationships between air quality, climate change, public health, and environmental policy.

Laura Haynes Gillam (invited), Senior Policy Advisor for Clean Air and Climate, U.S. Senate Environmental and Public Works Committee, will discuss what makes science useful to public policy, how scientists can most effectively engage with Hill staff, and what is needed to build and maintain a strong science-policy interface in the U.S. Congress. She will share specific examples from her experience on the Hill of what works, and what doesn’t.

Moderator Kathy Fallon Lambert, Senior Advisor at the Center for Climate, Health, and the Global Environment at the Harvard TH Chan School of Public Health will set up the session by offering an ex-post framework describing the components of a robust science-policy interface from these Clean Air Act examples. She will also offer synthetic remarks at the end of the session based on the ensuing group discussion.


  • Kathy Fallon Lambert, M.S., Senior Advisor, Center for Climate, Health, and Global Environment; Harvard Chan School
  • Charles Driscoll, University Professor, Syracuse University
  • Elsie Sunderland, Professor, Harvard University
  • Amelia Keyes, Research Associate, Resources for the Future
  • Susan Anenberg, George Washington University