Dust in the wind: How cities alter natural airborne particles

Summary

One of 20 dust collectors, Jeff Munroe, a geologist with Middlebury College, has deployed on mountaintops around the Southwest U.S. This one is in the Independence Mountains of northern Nevada. Credit: Jeff Munroe Airborne dust pollution is a growing problem for residents of Utah and other Western states, especially with the exposed lakebed of Great Salt Lake potentially becoming more hazardous as the lake dries. Natural dust blows from the Great Basin and settles along the western edge of the Wasatch Front, Utah's major population center, and the surrounding mountains. While airborne, the dust mixes with local human-made materials, potentially contaminating the nearby watershed and resulting in other negative consequences, according to new research from the University of Utah that investigates the influence of urban environments on transient dust. The findings are published in the journal Scientific Reports. A study team led by Utah atmospheric scientist Kevin Perry and Jeff Munroe, a geology professor at Middlebury College, considered Earth's "Critical Zone," a near-surface layer where organisms interact with rock, air, soils and water. Dust processes such as deposition, erosion and transport influence the Critical Zone. Dust particles are typically diverse in their composition, as they are influenced by natural environments. However, agriculture, grazing, off-roading, construction, mining and other human activities alter the dust composition, with important implications for places like Utah's populated Salt Lake Valley. "The problem is that there are lots of dust sources in the urban area, and when it's windy and it's picking up dust from the Great Salt Lake and other places upstream, it gets mixed in with this local dust that has a lot more junk in it," Perry said. "So if we think about the contaminants of concern in Great Salt Lake dust, and then you add in additional contaminants from the local dust, it just makes it that much more potent, and not in a good wa...