Air Quality in a Changing Climate

doi:10.1289/ehp.1103649 Once, in the not so distant past, smoke belching from urban factories and plants was viewed as a symbol of a prosperous, growing economy with abundant jobs. However, awareness of the downside of such pollution spawned the environmental movement of the 1960s, culminating in the Clean Air Act Amendment of 1970. This landmark legislation provided the regulatory mandates and legal tools that stimulated innovative technological efficiencies. Remarkably, over the next 40 years, emissions were brought down by more than two-thirds, even as productivity improved. Today, the absence of sooty urban air and the presence of clear vistas are the visible hallmarks of successful air pollution policies. Indeed, in the past two decades, the percentage of people who view the threat of air pollution with “a great deal of concern ” has been reduced by 25 % (Jones 2010). Even the Office of Management and Budget (2007) noted that air pollution regulations have yielded substantial benefits to the U.S. economy—providing $3 to $17 for every $1 spent over the previous 10 years on implementation of air rules. Ironically, about 127 million Americans still live in counties where air pollution levels exceed one or more of the six National Ambient Air Standards (NAAQS), and politicians still debate whether the health-based regulation of air quality is hurting the economy and stymieing job growth despite evidence to the contrary. For example