All Americans should be able to breathe clean air. But pollution from power plants and vehicles puts the health of our nation’s children and families at risk. Ground-level ozone, the main component of smog, is one of the most harmful and one of the most pervasive air pollutants. According to the American Lung Association, nearly half of all Americans – 48 percent – still live in areas with unhealthy levels of smog pollution. Studies show that on days with high concentrations of smog pollution in the air, children and adults suffer more asthma attacks, increased respiratory difficulty, and reduced lung function. Exposure to smog pollution can exacerbate respiratory illness and even cause premature death. Sensitive populations including children, the elderly, and people with respiratory illness are particularly at risk of the adverse health effects of air pollution.
Though air quality has improved significantly in the last decade as a result of policies at the state and federal level, there is still much to be done, as there are millions of people living in metropolitan areas around the country exposed to multiple days each summer when the air is unhealthy to breathe. This report ranks metropolitan areas for their unhealthy air days in 2010 and 2011. This report also presents data indicating that the problem may have been even worse than we thought. Because the national health standard for smog pollution set in 2008 was set at a level that scientists agree is not protective of public health, people across the country have been exposed to days of poor air quality each summer without even knowing it. We have calculated the additional days on which the air was unhealthy to breathe, according to a pollution threshold that is more consistent with what scientists say is necessary to protect public health. But because the 2008 standard was set too loosely, the public was not alerted to these days of unhealthy air.
Millions of Americans suffer from the harmful effects of ground-level ozone pollution, which exacerbates lung diseases such as asthma and can cause breathing difficulties even in healthy individuals. The result is more time spent in hospital emergency rooms, as well as additional sick days and even premature deaths. These health impacts not only involve suffering; they are also costly, constituting a significant drag on the U.S. economy. While power plants and cars are among the main sources of ozone-forming pollutants (the chemical precursors to ozone), ozone’s formation is dependent on temperature, among other conditions. As a result, climate change has the potential to increase ozone pollution—and its health and economic burdens—across large parts of the country both now and in the future.
This report from the Union of Concerned Scientists combines projections of future climate-induced temperature increases with findings on the relationship between ozone concentrations and temperature to illustrate a potential “climate penalty on ozone.”1 This penalty demonstrates how higher temperatures could increase ozone pollution above current levels, assuming that emissions of ozone-precursor pollutants remain constant.
We analyzed this climate penalty’s health consequences expected in 2020 and 2050, including increases in respiratory symptoms, hospital visits for the young and old, lost school days, and premature mortality, for most of the continental United States. We also projected the economic costs of these health impacts in 2020.