The study is the first to quantify pollution reaching the West Coast from the Chinese manufacturing sector that produces mobile phones to televisions for global export, according to a statement about the study from the University of California, Irvine, where one of the authors is based.
Los Angeles sees at least one extra day a year of smog that exceeds federal limits because of nitrogen oxides and carbon monoxide emitted by Chinese factories producing for export, the analysis found. China’s economic ascent has been accompanied by a surge in pollution and the World Bank estimates that the Asian nation has 16 of the 20 most-polluted cities globally.
“We’ve outsourced our manufacturing and much of our pollution, but some of it is blowing back across the Pacific to haunt us,” Steven Davis, a co-author of the study and an earth system scientist at the University of California, Irvine, said in the statement. “Given the complaints about how Chinese pollution is corrupting other countries’ air, this paper shows that there may be plenty of blame to go around.”
Winds called the “westerlies” can drive airborne chemicals across the ocean and lead to dangerous spikes in contaminants, according to the university’s statement. Dust, ozone and carbon may collect in valleys in California and other Western states, it said, while noting that China still isn’t responsible for the lion’s share of pollution in the U.S.
Jintai Lin of Beijing’s Peking University was the lead on the study and joined by experts at several global universities as co-authors.
In China, President Xi Jinping has pledged to tackle pollution amid rising public concern that smog and environmental degradation are affecting the nation’s health and the economy. The Ministry of Environmental Protection this month told all provinces and municipalities to cut air pollutants by as much as one quarter.
The Asian nation is the world’s largest emitter of anthropogenic air pollutants, according to the paper, with a fraction of its emissions caused by the manufacture of goods for foreign consumption. Anthropogenic pollutants typically refer to those originating from human activity.
In 2006, 36 percent of anthropogenic sulfur dioxide, 27 percent of nitrogen oxides, 22 percent of carbon monoxide, and 17 percent of black carbon emitted in China were associated with production of goods for export, according to the paper. For each of these pollutants, about 21 percent of export-related Chinese emissions could be traced to U.S.-related exports, the paper said.
Black carbon, linked to conditions including asthma and cancer, is a “particular problem,” according to the University of California statement.
On some days, the export-related Chinese pollution contributed to as much as 24 percent of sulfate concentrations over the western U.S., according to the study.
More than 600 million people were affected in China by a “globally unprecedented” outbreak of smog in the country that started last January and spread across dozens of provinces, lasting several months, Ma Jun, the founder and director of the Beijing-based Institute of Public & Environmental Affairs, told reporters on Jan. 15.
“Air pollution doesn’t have boundaries,” said Zhi Ning, an assistant professor at City University of Hong Kong’s School of Energy and Environment who isn’t connected to the latest study. “It can come from China to the U.S., but it can also go the other way.”
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