USA imports Chinese pollution

SUBHEAD: It takes 15 days for China's air pollution to reach the U.S. Blame ourselves for buying stuff made there.
Image above: Photo by Lu Guang of Chinese steel town pollution. From (

 By Staff on 21 January 2010 in New Scientist -  

Asia may be exporting more than just goods to the US. The world's emerging industrial hubs in the region seem to be sending harmful ozone towards North America. Emissions of gases such as nitrogen oxides are the primary source of ozone in the troposphere. These gases are both health hazards and greenhouse gases. Satellite studies between 1996 and 2005 suggest that there was a decrease in emissions of such ozone precursors from North America and Europe but an increase from China and other parts of Asia.

As ozone levels remain higher than estimated in North America, Owen Cooper of the Earth System Research Laboratory in Boulder, Colorado, and colleagues decided to investigate. They used data collected between 1995 to 2008 by balloons and aircraft fitted with ozone-measuring instruments. The team also used computer models and meteorological data to retrospectively work out the movement history of pockets of air that had passed over Asia during those years.

The team found that the air pockets that had the greatest probability of having passed near the land surface in east and south Asia were the ones found 15 days later in regions of the US that showed the greatest increase in ozone concentrations. This suggests that the emissions of ozone precursors came from Asia (Nature, DOI: 10.1038/nature08708).  

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