Sunset

Shown here is a view from Valle Crucis of the sun setting over Beech Mountain on June 25.

BOONE — A sweeping plume of dust — traveling 5,000 miles from the Sahara Desert to the U.S. — offered an unexpected bright spot for the High Country, along with an opportunity for university researchers at Appalachian Atmospheric Interdisciplinary Research (AppalAIR), last week.

According to CNN, though it is common for dust from the African desert to move across the Atlantic Ocean to the U.S., this storm is the largest of its kind in more than five decades — and with it came stunning sunscapes and potential health risks.

While much is known about these dust plumes, Bob Swarthout, an assistant professor who holds dual appointments in Appalachian’s A.R. Smith Department of Chemistry and Fermentation Sciences and Department of Geological and Environmental Sciences, said there is “still uncertainty about the mineral composition and size of Saharan dust particles transported to the U.S. and how much they contribute to air quality decreases.”

This uncertainty presents opportunities for researchers like James Sherman, a professor in Appalachian’s Department of Physics and Astronomy, to contribute to the growing knowledge base.

Sherman serves as senior research scientist at AppalAIR, where he manages National Oceanic and Atmospheric Administration (NOAA) and National Aeronautics and Space Administration (NASA) atmospheric monitoring sites. There, he and his research students from Appalachian study the effects of atmospheric aerosols — haze, smoke and dust — on climate change in the Southeast. AppalAIR’s field sites on Appalachian’s campus were continuously monitoring and measuring the dust storm.

“The unique capabilities of the collocated NASA/NOAA sites at Appalachian should provide quantitative information on the amount of dust, how high up it is in the atmosphere and its effect on sunlight, visibility and air quality,” Sherman said.

Sherman added that the NOAA and NASA sites at Appalachian have been acquiring data continuously for more than a decade. “App State is one of only two locations in the U.S. with such a suite of instruments and the only one relying exclusively on students for help with operations,” he said.

Swarthout said there are several positive effects of this dust storm. For instance, the dust will scatter more light than is normally scattered in the atmosphere, which will produce “strikingly red sunsets and sunrises.”

Additionally, Swarthout said the formation of tropical storms and hurricanes would be disrupted during the dust storm because “the dust is highly reflective compared to the surface of the ocean, so it blocks and reflects incoming sunlight, cooling the air and water.”

The dust plume also had the potential to present health considerations related to air quality.

“We are primarily concerned with exposure to the very smallest particles — those less than 10 micrometers in diameter and especially those smaller than 2.5 micrometers in diameter,” Swarthout said. “These are the size classes of particles that are associated with increases in respiratory problems and increased incidence of heart problems.”

According to Swarthout, reports from monitoring stations in the Caribbean have shown particle concentrations at the heart of the plume that are considered “hazardous” to all people.

Though the concentrations of particles will be diluted before reaching the High Country, Swarthout advised the area will probably see “concentrations considered to be unhealthy or unhealthy for sensitive groups” by Environmental Protection Agency standards.

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