Name: Russell B.
Status: student
Age: 17
Location: N/A
Country: N/A
Date: Wednesday, June 26, 2002
Question:
What is the range in size and origin of airborne particles?
Replies:
Russell,
Someone else may give a more detailed answer to this. However, particles from
nearly microscopic to tens of micrometers (called micron) in diameter can be
carried in air. The heavier particles can be carried short distances
(miles) by
strong turbulent winds, but eventually settle back to the ground. Particles
less than 3 microns can stay airborne for much larger distances (hundreds of
miles) before they settle out or are removed by rain. Particles less than a
micron can be literally carried around the Earth and into the upper parts
of the
atmosphere if the conditions are right.
Long-range transport of small particles from dry climates especially can
sometimes be seen in satellite photographs. A plume from the western Sahara
extends all the way to Florida at times and dust or sulfate particulates from
China can extend well out over the Pacific Ocean past Japan.
Particles from volcanoes often end up in the stratosphere and stay there for
several years, circling the Earth.
David R. Cook
Atmospheric Research Section
Environmental Research Division
Argonne National Laboratory
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