Shouldn’t your car be clean after a rainstorm?

Tuesday, July 10, 2018 - 09:35
UNT Physics researchers Todd Byers (foreground) and Jack Manual conduct a proton induced x-ray emission (PIXE) analysis on dust.
UNT Physics researchers Todd Byers (foreground) and Jack Manual conduct a proton induced x-ray emission (PIXE) analysis on dust.

DENTON (UNT), Texas – The dusty coat on your car after a rainstorm has a real purpose in our ecosystem, according to a recent scientific study led by UNT Department of Geography and the Environment Professor Alexandra Ponette-Gonzalez.

This study marked the first time that the composition, frequency and amount of dust in rainwater have been quantified in Texas and showed that dust can travel across oceans before being deposited into new environments through rainwater, sometimes bringing with it vital nutrients and sometimes pollutants.

“When most people think about what is in rainwater, the first thing that comes to mind is pollutants. We have found that is not always the case. In some instances, dusty water is literally needed to make the plants grow,” said Ponette-Gonzalez.

She found that droughts, like the one that struck Texas in 2012, bring major dust storms and also lead to dustier rain.

“In some of the areas we sampled,” Ponette-González said. “One third to one half of the calcium in the soil came from dusty rain over the course of a year. After dust is lifted from the ground, it can travel long distances, even around the world. It has been found to carry everything from plant nutrients, like phosphorus and iron, to pollutants, like copper and zinc.”

Ponette-González, Gary A. Glass, professor of physics at UNT, Kathleen C. Weathers, senior scientist at the Cary Institute of Ecosystem Studies, Joe D. Collins, assistant professor of geomorphology at Middle Tennessee State University and Thomas E. Gill, a professor with both the Department of Geological Sciences and the Environmental Science and Engineering Program at the University of Texas – El Paso, studied rainwater samples collected during the major 2012 drought in Texas to determine which ones had dust in them and what the dust contained. They found that dusty rains delivered huge amounts of nutrients and pollutants across the state. This study is the first to quantify dust in Texas rainwater.

The paper, Wet Dust Deposition across Texas during the 2012 Drought: An Overlooked Pathway for Elemental Flux to Ecosystems, was published July 6 in the American Geophysical Union’s Journal of Geophysical Research: Atmospheres.

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