Tiny dust particles from Asian deserts common over western Uni...(stern United States. She looked at dust ...)

The research is being presented at this year's annual meeting of the American Geophysical Union in San Francisco.

For the dust detected at ground stations in the United States, Fischer also looked for and found evidence of calcium, which is a tracer for desert dust.

"The calcium lends more confidence to our conclusion," she said.

While the results of the research are not unexpected, they provide supporting evidence that particles of 2.5 microns or smaller appear in higher concentrations in the western United States in years when there are high dust concentrations over Asian deserts.

"The transport of dust across the Pacific is not a new phenomenon," Fischer said. "But we are just beginning to understand it and quantify it on a year-to-year basis instead of on a case-by-case basis.

"We know that just having dust over Asia doesn't mean that it's going to come here. There is the transportation part of the puzzle, which I'm working on now. But we already know that some years are more favorable than others for dust to be transported across the Pacific."

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