Forget Secondhand Smoke—Start Worrying About Secondhand Smog

Researchers discover that 10 percent of the harmful ozone in California’s polluted San Joaquin Valley comes from Chinese coal plants.

(Photo: Getty Images)

Apr 1, 2015· 1 MIN READ
John R. Platt covers the environment, wildlife, and technology and for TakePart, Scientific American, Audubon, and other publications.

Does the beating of a butterfly’s wings in China set off a tsunami of health problems in California? Not exactly, but new research has revealed that China’s coal plants are contributing to smog problems all the way across the Pacific Ocean in California’s San Joaquin Valley, one of the most polluted areas in the United States.

That “secondhand smog” is, in turn, affecting people’s health.

The Chinese coal plants contribute about 10 percent of the ozone in Fresno, Stockton, Bakersfield, and the surrounding cities, but it adds up. Bakersfield has the third-highest ozone levels of any major U.S. metropolitan area, according to the American Lung Association’s annual State of the Air report, which gives the entire region a failing grade for air quality. Researchers found that nearly 12 percent of Bakersfield’s residents suffer from pollution-related asthma or COPD, which is about twice the national average.

Ian Faloona, an atmospheric scientist at the University of California, Davis, who led the new study, said in a statement that this shows pollution is a global problem that can affect people no matter where they live.

“How do we deal with this not just as an air district of a couple of counties, but as a nation and a global citizen of the planet?” he said. “Traditionally, air pollution has always been considered an issue to be handled locally: ‘It’s your backyard, it’s your problem.’ But we’re going to have to treat air pollution to some extent how we treat greenhouse gases.”

Faloona and his team spent three years collecting air samples from a mountaintop station and by airplane. They tested each sample for ozone and accompanying tiny particles, some of which showed elemental compositions of sodium, iron, calcium, and aluminum that could be linked to coal mined and burned in China.

“These things have different elemental ratios when the soil came from Asia versus North America,” he said in an interview. “When we see this combination of factors, we think this is predominantly of Asian origin.”

The preliminary details of the team’s work were presented on Tuesday at the Transboundary Ozone Pollution Conference outside Yosemite National Park. They have not yet been published in a peer-reviewed journal. The conference was organized by the San Joaquin Valley Air Pollution Control District, whose executive director, Seyed Sadredin, called ozone a “tremendous public health challenge.” The district also funded Faloona’s research.

The California smog research was released the same day as a similar study that found pollution from factories in China and other countries in Southeast Asia travels 1,000 kilometers a day and is creating air-quality issues deep in the rainforests of Borneo. Lead researcher Matthew Ashfold from the University of Nottingham’s Malaysia campus said this impacts not just Borneo but the entire world, because “the region is an important source of air for the stratosphere.”

Faloona made a point of not blaming China for the pollution in California, saying that most of the ozone in the region came from local sources. He said this research shows that “air is something we have to share,” and “all of our decisions have to be made on a global scale from here on in.”