Climate Change May Cause 70 Percent Increase in Unhealthy Ozone Levels by 2050

It turns out that the United States may be having a lot more trouble with ozone pollution in the future. Researchers have found that Americans face the risk of a 70 percent increase in unhealthy summertime ozone levels by 2050 as temperatures continue to rise.

"It doesn't matter where you are in the United States-climate change has the potential to make your air worse," said Gabriele Pfister, one of the researchers, in a news release. "A warming planet doesn't just mean rising temperatures, it also means risking more summertime pollution and the health impacts that come with it."

Ozone pollution isn't emitted directly. Instead, it forms as a result of chemical reactions that take place between nitrogen oxides and organic compounds in the presence of sunlight. These gases can come from the combustion of coal and oil as well as from natural sources, such as emissions from plants. Yet unlike ozone in the stratosphere, which blocks ultraviolet radiation from the sun and benefits our Earth, ground-level ozone and trigger health problems.

In order to examine how much ozone we may have to deal with in the future, the researchers examined two different climate scenarios. In one, emissions of nitrogen oxides and organic compounds would continue at current levels. In the other scenario, emissions would be cut by 60 to 70 percent.

So what did they find? If emissions continue at present rates, the number of eight-hour periods in which ozone would exceed 75 parts per billion would jump by 70 percent by 2050. In addition, researchers found that 90 percent of the time, ozone levels would range from 30 to 87 ppb in 2-5- compared with 31 to 79 ppb in the present.

Yet it isn't all bad news. Reducing emissions showed a drastic decrease in problems. In fact, 90 percent of the time, ozone levels would range from 27 to 55 ppb.

"Our work confirms that reducing emissions of ozone precursors would have an enormous effect on the air we all breathe," said Pfister in a news release.

The findings are published in the Journal of Geophysical Research-Atmospheres.