On the West Coast of the U.S., pollution blown in from China can account for 12 to 24 percent of sulfate concentrations on any given day, a study published Monday in the Proceedings of the National Academy of Sciences found. That pollution caused Los Angeles to experience an extra day of smog levels that were above the federal health standards for ozone in 2006.
But though the pollution comes from China, the U.S. still bears part of the responsibility. That’s because about a fifth of China’s air pollution comes from the manufacture of goods for export to other countries, including the U.S., China’s second-largest trading partner. The study found that manufacturing for the export sector contributed to 36 percent of China’s sulfur dioxide emissions, 27 percent of its nitrogen oxides, 22 percent of its carbon monoxide and 17 percent of its black carbon — a pollutant linked to cancer, emphysema and asthma.
“When you buy a product at Wal-Mart, it has to be manufactured somewhere,” Steve Davis, co-author of the study and University of California at Irvine scientist told the Washington Post. “The product doesn’t contain the pollution, but creating it caused the pollution.”
China’s pollution has been setting records recently — in December, Shanghai was hit with a week of air pollution so bad that it cancelled flights and sporting events and forced children and the elderly indoors. And last week, Beijing experienced its first off-the-charts air pollution of 2014. China has implemented pollution reduction targets and a carbon trading scheme in some major cities, but in 2013 the country also approved the construction of $10 billion worth of new coal production capacity.
An oft-cited argument against measures to reduce emissions in the U.S. is that if major polluters like China and India don’t also reduce their emissions, a U.S. effort won’t make a difference. But Davis said that the study’s conclusion that China’s emissions directly affect the U.S. proves that the world needs to “move beyond placing blame” and realize that reducing pollution is within everyone’s common interest.
“We’ve outsourced our manufacturing and much of our pollution, but some of it is blowing back across the Pacific to haunt us,” Davis said. “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.”