tat, and food production (IPCC 2007, 2012). The scientific and technical challenges associated with the goal of taking action on climate change and improving air quality are broad and complex. Finding efficient and effective approaches to mitigate and adapt to climate change and improve air quality requires systems thinking and research in diverse disciplines, including environmental engineering, atmospheric sciences, biology, ecology, engineering, economics, sociology, and public health. EPA has been involved in climate-change research and policy development for more than 2 decades see (Box 2-1). Beyond its statutory assignments, EPA undertakes broader efforts to address climate change and improve air quality through various approaches that include public education, consumer information, technical exchanges, grants, and voluntary certification programs.
Regulatory Drivers for Air Quality and Climate Change
EPA’s regulatory drivers in the climate-change and air-quality arena have helped to marshal resources in and outside the agency, which has yielded substantial advances in scientific understanding and technology. For example, designation of particulate matter and photochemical oxidants as criteria pollutants under the Clean Air Act has led to thousands of epidemiology and toxicology studies that have improved the understanding of associated health effects and provided the scientific basis of standard-setting and regulatory efforts. In contrast, one challenge posed by regulatory drivers is the blind spots that they create for issues deemed outside the scope of regulatory authority or issues that have lower priority because of later deadlines or milder penalties for noncompliance. For example, EPA recognizes both indoor pollution and outdoor air pollution as posing important health risks, but the agency places relatively low priority on indoor air-quality research due to lack of a regulatory mandate. The structure of the Clean Air Act has also encouraged heavier emphasis on criteria pollutants over other hazardous air pollutants, human health over ecosystem effects, and industrial sources over agricultural sources of pollutants. EPA faces a challenge in trying to balance its own research portfolio between issues that arise out of its regulatory mandate and issues that warrant attention from the perspective of human health and welfare but for which there is no legislative mandate. Approaches for how EPA can support and promote science and engineering in the face of these challenges are discussed in Chapters 4 and 5.
Continued research efforts and leadership are important for a strong understanding of the health effects and fate and transport of conventional air pollutants, including both hazardous air pollutants and criteria pollutants, and understanding the synergistic effects of air-pollutant mixtures. EPA would benefit from advancing the understanding of sources, transformations, and transport of pollutants, including improved quantification and forecasting of international contributions to US air-quality challenges (for example, mercury deposition and