Half The Aerosols Affecting North America Climate Change Are From Foreign Countries: 94 Percent Is Dust From Foreign Countries And Only 6 Percent Is Industrial Emissions From Foreign Countries: Curbing Industrial Emissions Alone Is Not Enough

From "N. American air suffers from foreign dust" on ScienceBlog:

Roughly half the aerosols that affect air quality and climate change in North America may be coming from other continents, including Asia, Africa and Europe,....

Atmospheric particles can travel thousands of miles downwind and impact the environment in other regions, found lead researcher Hongbin Yu of the University of Maryland, and his team in a report published in the August 3, 2012 issue of the journal Science. This could offset emission controls in North America and suggests there are more factors affecting domestic pollution than the Environmental Protection Agency has accounted for.

"People have been concerned about how an emerging Asian economy and increased manmade pollution will influence North American air quality and climate, but we found that dust makes large contributions here," explained Yu, an associate research scientist in UMD’s Earth System Science Interdisciplinary Center (ESSIC). "So we cannot just focus on pollution. We need to consider dust."***Most of the pollution migrating into the North American atmosphere is not industrial emissions but dust from Asia, Africa, and the Middle East, Yu found. Out of the total annual accumulation of foreign aerosols, 87.5 percent is dust from across the Pacific, 6.25 percent is comprised of combustion aerosols from the same region and 6.25 percent is Saharan dust from across the Atlantic.***UMD climate scientist Antonio (Tony) Busalacchi, who is chairman of the Joint Scientific Committee for the World Climate Research Programme and chairman of the Board on Atmospheric Sciences and Climate of the U.S. National Academy of Sciences/National Research Council, says one of the most interesting points Yu and his coauthors make in their study is that even a reduction of industrial emissions by the emerging economies of Asia could be overwhelmed by an increase in dust emissions due to changes in meteorological conditions and potential desertification. [Emphasis added.]