China air pollution affecting California

Date of Release: 
Aug 11 2015

Aside from smartphones, toys and computers, China exports a different kind of product into the western United States — air pollution.

A study released by the Jet Propulsion Laboratory and NASA found that smog-forming chemicals making their way across the Pacific Ocean from China are undermining the progress California has made in reducing ozone, the most caustic component in L.A. smog.

From 2005 through 2010, western states have cut ozone-forming air pollutants by 21 percent, but the NASA/JPL study found no drop at all when measuring smog-forming gases in the midtroposphere, located 10,000 to 30,000 feet above ground level.

Just under half of what should have been a 2 percent drop was offset by China’s contribution, stemming from a 21 percent rise in ozone-forming pollutants emitted by car tailpipes and coal plants from a robust Chinese economy during the six years studied. Slightly more than half was due to natural causes — stratospheric ozone descending through the sky as a result of cyclical atmospheric winds helped by an El Niño in 2009-2010, the scientists concluded.

“The contribution from China increased steadily throughout the study, and we don’t know what will happen to it in the future because it depends on human rather than natural factors,” said JPL scientist Jessica Neu, co-author of the study with Willem Verstraeten, an atmospheric chemist at Wageningen University in the Netherlands. The study was published Monday in the online journal Nature Geoscience.

“In a manner of speaking, China is exporting its air pollution to the West Coast of America,” Verstraeten told the online publication phys.org.

About half of the pollutants in the midtroposphere reach the surface as ozone and affect the air people breathe, Neu said. Ground-level ozone causes shortness of breath, eye irritation and sore throats, and long exposure can prematurely age the lungs and cause lung disease, according to the U.S. Environmental Protection Agency and hundreds of studies done in Southern California.

Previous studies published in the Journal of Geophysical Research-Atmospheres in 2012 estimated Asian pollution accounts for about 20 percent of the total ozone pollution in the spring in the western states such as California, Oregon, Washington, Montana and Wyoming. Some scientists estimate Asian air pollution pushes Southern California above the 75 part per billion federal hourly ozone standard for about 53 percent of the recorded exceedances.

The most recent study quantifies the impact of Chinese air pollution on the West Coast. It also raises the issue of whether countries need to treat smog as a global pollutant that knows no borders.

Source URL: Daily Democrat

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