Pollution from China’s export manufacturing sector is blowing across the Pacific Ocean to reach the US West Coast, according to a paper published in the Proceedings of the National Academy of Sciences, Bloomberg reported, citing a statement from the University of California, Irvine. Los Angeles experiences at least one extra day per year of smog that exceeds federal limits because of nitrogen oxides and carbon monoxide emitted by Chinese factories. Winds called “westerlies” can drive airborne chemicals across the ocean and lead to dangerous spikes in contaminants in California and other Western US states.