"It has the potential to cause respiratory problems, if you're sensitive to fine particulates," he says. "It effected me a little bit."
Choking on Sand
Long range transport of dust is not a new problem. Occasionally, dust storms in Africa's Sahara Desert reach Florida, and it's not altogether a bad thing. Dust from those storms transport many nutrients, including iron, enriching soils in one area of the Earth at the expense of another.
And of course we all know these days about what dust did to the dinosaurs. Most scientists now believe that dust from the impact of the Earth with a giant meteor or asteroid blackened the sky so intensely and for so long that food resources around the globe died out, killing off the dinos.
No one is suggesting that the dust storms in Mongolia pose any such threat. At this point it is more a matter of intense scientific interest than anything else. NASA, the National Science Foundation, and the National Oceanographic and Atmospheric Administration are all intensifying their research in the area.
It turns out the timing is ideal. A team of American researchers is already in Asia studying aerosol particles and their effect on Earth's climate, and a second dust storm has kicked up enough stuff to give them much to ponder.
On Tuesday the National Oceanic and Atmospheric Administration reported the second storm was already looming over Colorado. If it holds together, the dusty system is expected to reach the East Coast by Saturday.
As for the cloud that darkened the normally pristine skies of northern Arizona, it eventually moved on, according to NOAA.
By April 19, it had reached the East Coast, stretching from Hudson Bay to Northern Florida, and then it moved on out to sea.
What did it leave behind? Some dust, and some marveling over the complexity of a planet that just seems to be getting smaller and smaller.
Lee Dye’s column appears weekly on ABCNEWS.com. A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.