A dust storm that began more than two weeks ago on the Mongolian-China border covered areas from Canada to Arizona with a layer of dust quadrupling particulate pollution across the western United States.
In Aspen, Colorado, particulate levels measured 58 millionths of a gram per cubic metre of air, compared with 14 millionths of a gram a week earlier. High particulate concentrations have meant reduced visibility and an increase in respiratory problems.
In Denver and along the foothills of the Rockies, the mountains were obscured by the haze. Russ Schnell, Director of Observatory Operations at the Climate Monitoring and Diagnostics Laboratory at the National Oceanic and Atmospheric Administration in Boulder, Colorado, said the dust had swirled in for several days but was now leaving the Colorado area. “It’s moving on now and is being diluted by clouds and weather systems,” he said. “It was very unusual for this dust cloud to have hung together as long as it did.”
Satellite images show a thick, yellow swirl of dust streaming out across Korea and the Pacific Ocean. The plume that hung over the Colorado area was about four miles thick Schnell said. “Over the last few years, there has been a growing awareness that air pollution from China is affecting us. Pollution is a global problem. Nature has sent us a perfect storm to reinforce the fact that we are all downwind of someone else’s pollution,” the expert said.
Dust storms from Asia are not uncommon, although this latest one has been particularly noticeable with atmospheric scientists being aware that the westward airstream has brought pollution from Asia across the oceans. As the Chinese economy grows, the resulting pollution is predicted to become increasingly problematic in the United States.