Scientists looking into air quality and climate change have found pollutants from as far as Asia over New England and the Atlantic.
It is the first time Asian pollution plumes have been observed over the East Coast and suggests that American air quality could be threatened as Asian countries become more industrialized.
"We have to be concerned whether the cost of continuing to ratchet up emission controls is not going to be offset by growing pollution coming to us from Asia," Daniel Jacob, a Harvard University researcher, told The Boston Globe.
"At some point, it may be cheaper to sell pollution control equipment to China," he said.
The Asian pollution was spotted above Portsmouth and other locations this by the International Consortium for Atmospheric Research on Transport and Transformation, an air quality study billed as the largest, most comprehensive ever done. The six-week study by researchers from six nations began July 5.
"I think what you're going to see in five to 10 years' time, when you get a better handle on the long-range transport, is that pollution is traveling from continent to continent and there may need to be some new agreements put into place," said Robert Talbot, a University of New Hampshire's scientist.
Talbot also believes results of a parallel New England Air Quality Study may surprise the region, which often blames other regions for creating the smog that drifts in on prevailing winds.
"I think there's quite a bit of pollution generated within the region that we're not really recognizing," said Talbot.
The Asian pollution was identified through chemical fingerprints _ halocarbons produced only in Chinese industry, said Jacob.
"I think the most profound thing that you draw from this is that the globe is one air shed," said Armond Cohen, director of the Clean Air Task Force, a Boston-based nonprofit.
"Right now, there's a lot of interest in the community about this influence of Asian pollution and whether it can compromise our ability to achieve regional air quality objectives," said Jacob.
"We knew the transport from Asia was efficient in the spring, but we didn't know it was so prevalent in the summer," Talbot said.
Three years ago, an Asian storm sent dust across the United States, sprinkling it as far as New Hampshire. Forest fires raging through Quebec in 2002 blanketed New England and much of the East Coast. And divisive battles long have been fought over border-crossing gases.
In recent years, Northeastern states have been suing over the pollution blown from the Midwest, blaming power plants for producing acid rain and ozone, and, most recently, exacerbating global warming. In 1991, the United States signed a treaty with Canada agreeing to reduce U.S. emissions blamed for spoiling lakes and forests with acid rain.