Historical Context for Radioactive Particulates Moving from Asia to the US

As as the Lawrence Berkeley National Laboratory wrote last December:

About a third of the airborne lead particles recently collected at two sites in the San Francisco Bay Area came from Asia, a finding that underscores the far-flung impacts of air pollution and heralds a new way to learn more about its journey across vast distances.

In a first-of-its-kind study, scientists from the U.S. Department of Energy's Lawrence Berkeley National Laboratory and the California Air Resources Board tracked variations in the amount of lead transported across the Pacific over time.

It's well known that particles and other aerosols cover long distances through the Earth's atmosphere. But the details of this transport, such as that of the lead particles' 7,000-mile journey from the smokestacks of China to the west coast of North America, are largely unknown.

From 2001:

http://earthobservatory.nasa.gov/IOTD/view.php?id=1352

From 2010:

http://newscenter.lbl.gov/feature-stories/2010/12/01/lead-isotopes-air-pollution/

From 1998:

http://www.agu.org/journals/ABS/2001/2000JD900758.shtml