China Exports One Smoggy Day to LA Each Year

You can offshore manufacturing, but a new study shows that doing so doesn’t mean you’ll fully escape the pollution.

We’ve known for some time that roughly one third of China’s greenhouse gas emissions and up to 36 percent of China’s overall pollution can be tied directly to the nation manufacturing so many goods for global export, with about one fifth of that linked to goods destined for the United States. Now, for the first time, researchers have tracked how much of that pollution is literally blowing back across the Pacific, and reaching US shores.

The report authors are careful to note that the overwhelming majority of pollution in the United States comes from domestic sources, but that at certain times of the year, particularly in spring, Chinese pollution can cause spikes in pollution across California and other western states.

According to this study, published in Proceedings of the National Academy of Sciences, up to one quarter of sulfate pollution on the West Coast can be traced back to Chinese factories making goods for export. Overall, pollution being dragged across the Pacific by the wind is responsible for Los Angeles experiencing one additional day each year where smog exceeds federal ozone limits. Smaller amounts of black carbon pollution, a significant component of both climate change and unhealthy air quality, also reaches the west coast of North America.

Previous research, conducted by the US Department of Energy, found that one third of airborne lead particles in the San Francisco Bay area could be traced to pollution originating in Asia.

Image: UC Irvine

The report’s authors, spread out across universities in China, the US, and the UK, concluded, “International cooperation to reduce transboundary transport of air pollution must confront the question of who is responsible for emissions in one country during production of goods to support consumption in another.”

Study co-author Steve Davis, of UC Irvine, added, “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.”

Historically, international cooperation to end transboundary pollution has shown to be successful—both acid rain and the hole in the ozone layer have been tackled in this manner. Climate pollution has obviously proven to be a more divisive issue. Here, no nation much wants to confront the issue of transboundary pollution, most of the greatest polluting nations being content, instead, to point fingers at one another demanding someone else act first to stop it.

Hopefully what studies like this can do is show, in specific terms, how pollution respects no man-made boundary, and hthat international negotiations have to recognize this.