The authors found that Los Angeles “experiences at least one extra day a year of smog” exceeding federal ozone limits thanks to Chinese factories making goods for export. On some days, “as much as a quarter of the sulfate pollution on the U.S. West Coast is tied to Chinese exports.”
On the other hand, because the Eastern United States has more population density, the authors, from a number of U.S. and Chinese universities, found that the outsourcing of manufacturing from the United States to China actually has an “an overall beneficial effect for the U.S. public health.”
This is one area where China may have something of a point when it comes to culpability for emissions. China’s pollution isn’t solely of its own doing. They’re tied to an export economy making goods for other countries, the U.S. most of all. America’s emissions are lower partially because China’s are higher. Viewed a different way, this is not so much a question of "China's smog" reaching America as the vast majority of smog from the manufacture of American goods staying in China. Of course, as China’s economy continues to shift from export to consumption, this equation is going to change.
Back in the U.S., the outsourcing of manufacturing has had innumerable negative consequences, but—particularly if you live on the East Coast—your lungs are better off for it.