America seems to be more and more linked to Asia--not just by complicated financial ties, but also by currents of air pollution that are boosting smog levels in American skies. For years scientists wondered why some rural areas in the western United States had high levels of ozone, when the areas had very little industry or automobile traffic. The answer, apparently, was blowing in the wind. A new study, published in Nature reveals that springtime ozone levels in western North America are on the rise, because of air pollution coming in from south and east Asia.
The study, led by Owen R. Cooper, an atmospheric scientist at the University of Colorado, examined nearly 100,000 observations two to five miles above ground -- in a region known as the free troposphere -- gathered from aircraft, balloons and ground-based lasers [Los Angeles Times].
This is the area between the stratosphere, that contains ...
