Smoke billows from the chimneys of a heating plant in Jilin, China. Pollutants wafting in from China have harmed air quality on the U.S. West Coast, according to a new scientific study. (REUTERS)

Bad air from China is blowing across the Pacific Ocean and contributing to smog in the United States, according to new scientific research.

And much of that air pollution is being caused by the manufacture of goods in China for export to the United States and Europe.

“We’ve outsourced our manufacturing and much of our pollution, but some of it is blowing back across the Pacific to haunt us,” said Steve Davis, a University of California at Irvine scientist and a co-author of the study. “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.”

The paper was published in the Proceedings of the National Academy of Sciences on Monday and, according to its researchers, is the first to quantify how much of the pollution reaching the West Coast of the United States is caused by production in China.

A decrease in manufacturing in the United States in recent years has led to cleaner air in its Eastern regions. But pollutants wafting in from China have harmed the West, according to the study.

Los Angeles has at least one additional day each year that exceeds federal ozone standards because of nitrogen oxides and carbon monoxide emitted by Chinese factories. And as much as a quarter of the sulfate pollution on the West Coast can be tied to Chinese exports, the report says.

China’s booming economy in recent decades has come with heavy environmental costs, generating international criticism. The study’s authors suggested in a statement that their findings could help spur the negotiation of clean-air treaties.

“When you buy a product at Wal-Mart,” Davis said, “it has to be manufactured somewhere. The product doesn’t contain the pollution, but creating it caused the pollution.”

The study is the work of nine scientists from three countries, including lead author Jintai Lin from Beijing’s Peking University.