Climate change threatens to worsen U.S. ozone pollution

http://www2.ucar.edu/atmosnews/news/11540/climate-change-threatens-worsen-us-ozone-pollution

May 05, 2014

BOULDER—Ozone pollution across the continental United States will become far more difficult to keep in check as temperatures rise, according to new research led by the National Center for Atmospheric Research (NCAR). The detailed study shows that Americans face the risk of a 70 percent increase in unhealthy summertime ozone levels by 2050.

This is because warmer temperatures and other changes in the atmosphere related to a changing climate, including higher atmospheric levels of methane, spur chemical reactions that lead to ozone.

Unless emissions of specific pollutants that are associated with the formation of ozone are sharply cut, almost all of the continental United States will experience at least a few days with unhealthy air during the summers, the research shows. Heavily polluted locations in parts of the East, Midwest, and West Coast in which ozone already frequently exceeds recommended levels could face unhealthy air during most of the summer.

“It doesn’t matter where you are in the United States—climate change has the potential to make your air worse,” said NCAR scientist Gabriele Pfister, the lead author of the new study. “A warming planet doesn’t just mean rising temperatures, it also means risking more summertime pollution and the health impacts that come with it.”

However, the research also showed that a sharp reduction in the emissions of certain pollutants would lead to dramatically decreased levels of ozone even as temperatures warm.

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Unlike ozone in the stratosphere, which benefits life on Earth by blocking ultraviolet radiation from the Sun, ground-level ozone can trigger a number of health problems. These range from coughing and throat irritation to more serious problems, including aggravation of asthma, bronchitis, and emphysema. Even short periods of unhealthy ozone levels can cause local death rates to rise. Ozone pollution also damages crops and other plants.

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