Washington, Aug 23 (IANS) About half of the aerosols affecting air quality as well as causing climate change over North America seem to be originating from other continents, including Asia, Africa and Europe, says a study.
The study was led by researchers from the University of Maryland, College Park, NASA Goddard Space Flight Center, University of Maryland, Baltimore, and the Universities Space Research Association.
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, the journal Science reports.
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, according to a Maryland statement.
"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," said Yu, associate research scientist at the University of Maryland's Earth System Science Interdisciplinary Centre (ESSIC).
The study, which provides the first satellite-measurement-based estimate of the amount of airborne particles that come to North America from overseas, shows this migrating dust usually comes in at high altitudes and is likely to affect upper atmospheric conditions in the region.
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 composed of combustion aerosols from the same region and 6.25 percent is Saharan dust from across the Atlantic.