The American west鈥檚 dusty portrayal in movies and literature is no exaggeration 鈥� after the first settlers arrived, dust levels in the region soared.
Jason Neff of the University of Colorado at Boulder and colleagues studied sediment samples from two lakes in Colorado鈥檚 San Juan mountains. They found atmospheric dust levels in the area jumped fivefold around 150 years ago, and have remained at that level ever since.
The team reckons the advent of large-scale agriculture and railway building must have kicked up the dust (Nature Geoscience, ). 鈥淟ooking at their data, it鈥檚 almost like a switch was flipped,鈥� says Aiguo Dai of the National Center for Atmospheric Research in Boulder.
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鈥淟arge-scale agriculture and railway building kicked up dust into the atmosphere鈥�
Dust can have profound effects on ecosystems, Neff says. The soil contains nutrients which, if blown away, can leave an area barren. If dust is deposited on a snowpack, it can accelerate melting. What鈥檚 more, dust tends to stick to other air pollutants, causing respiratory problems.
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