MILLIONS OF AMERICANS SUFFER from the harmful effects of ground-level ozone pollution—be they children too sick to go to school, high school football players not allowed to practice outdoors in the summer, 65-year-olds with lung disease unable to take a walk in the park, or farmers at risk when they harvest their fields. Not only does ozone pollution cause a number of serious breathing problems, and therefore a great deal of suffering, it also is damaging in monetary terms. Whether tallying up the dollars lost to sick days or the high costs of emergency room visits, ozone pollution is...

WHEN WEATHER FORECASTERS warn about poor air quality or “bad air days” and report an associated color to indicate healthy or unhealthy air (Figure 2), they are usually referring to the level of smog—a hazardous mixture of air pollutants that affect the health and quality of life of children and adults alike.

Ground-level ozone—the primary component of smog—is formed when oxides of nitrogen (NO_x) and volatile organic compounds (VOCs), which are “precursor emissions,” chemically react in the presence of heat and sunlight. Some of the major human-made sources of these precursor emissions are power plants, vehicles and...

Four key steps are involved in this report’s analyses of a) the effect that a warmer world could have on ozone pollution and b) the associated health and economic impacts across much of the United States (more detail on all of these steps can be found in the technical appendix online):

We surveyed the published studies to pick a “climate penalty factor,” reviewing both measured data and model projections pertinent to the relationship between temperature and ozone (Bloomer et al. 2009; Jacob and Winner 2008 [and references therein]; Steiner et al. 2006; Taha 2001). Selection of the climate penalty factor...

Ground-level ozone, the primary component of smog, irritates the lungs’ mucous membranes and other tissues, thereby compromising a person’s ability to breathe (Figure 6). Exposure to an increase in ozone concentrations¹⁸ on the order of 10 ppb—beyond an already elevated background level—is associated with increased hospital admissions for pneumonia, asthma, allergic rhinitis, and other respiratory diseases, as well as with premature death. By exacerbating respiratory problems, higher ozone pollution levels send more people to the doctor’s office and hospital emergency room and lead to more lost work and school days (Ito, De Leon, and Lippman 2005).

Ozone is...

OZONE POLLUTION IS PROJECTED to get worse with future warming. But how much worse might it be in a world of increasing temperatures? And what would be the implications for the health of our families and our pocketbooks? This report seeks to address these questions by drawing on well-established scientific literature as well as by conducting a new modeling analysis of health impacts and related costs.

This report takes a multidisciplinary approach in evaluating the potentially serious consequences of climate change for ozone pollution and human health in 2020 and 2050. We first surveyed published studies on the relationship between...

WE PRESENT THE OVERALL health impacts of the climate penalty on ozone for 40 states and the District of Columbia (hereafter referred to as “the US-40”) for 2020 and 2050. We also present these health impacts in terms of economic costs for the US-40 for 2020. In addition, we present the 10 worst-affected states in 2020 in terms of health and economic impacts. In each case, our results represent an additional impact above what would have occurred without the climate penalty on ozone.

Our results are derived from a 1 ppb and a 2 ppb ozone increase in 2020 and...

MANY STATES ARE ALREADY struggling with meeting ozone standards, as evidenced by the fact that over 48 percent of Americans currently live in areas with unhealthful ozone levels (ALA 2011: Figure 2). In a warming world, even greater numbers of states could face the health and economic consequences of failing to meet these minimally protective ozone standards. At the very least, the climate-change-induced increase in ozone pollution imposes an additional challenge for the states that currently have areas with unsafe ozone levels: they must work harder to reduce ozone-forming pollutants simply to maintain their current—and often unhealthful—ozone levels...