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 niversity of California, Davis researchers reported
last month that rising industrialization in Asia is discharging
millions of tons of previously undetected contaminants annually
into the winds that travel across the Pacific Ocean. These aerosols
make people sick and destroy crops in Asia, may be polluting
American waters, and could dramatically change global climate.
 The
researchers also described their role in the forthcoming ACE-Asia
project. ACE-Asia, for Aerosol Characterization Experiment, will
be the world's largest attempt to identify the exact sources
and destinations of those tiny particles of dust, sulfate and
organic matter. This information does not exist for much of Asia
and is badly needed by scientists trying to generate reliable
predictions of global climate change.
"Previous
research has shown that every spring there are massive dust storms
in Asia that transport soil eastward to Japan and across the
Pacific to the United States. Now we've found that sulfate and
organic aerosols are also present, and in roughly the same amounts,"
said Thomas Cahill, a UC Davis professor emeritus of physics
and atmospheric science and an international authority on the
atmospheric transport of pollutants.
"That
is very important for several reasons. First, the northern Pacific
Ocean is one of the last really clean areas of the Northern Hemisphere.
If we start to pollute the air above that ocean, we'll change
the balance of heating and cooling of the ocean and that will
produce changes in the weather.
"Second,
there are increasing numbers of reports of what appear to be
toxic Asian pollutants in the lakes and streams of North America.
"Finally,
and perhaps most important, there is an established link between
aerosol levels and rates of illness and death in people. Working
with our Asian colleagues, we hope to help them efficiently address
the causes of these aerosols and aid in developing mitigation.
The findings may prompt Asian policy-makers to restructure developmental
mandates to take into account the devastating air-quality problem
they have," Cahill said.
Asia is the
largest source of aerosols in the world, Cahill said. That's
largely because the region burns millions of tons of coal annually
from its abundant coal deposits. Aerosols are released from coal-burning
power plants and coal-fired locomotives; heavy industry, such
as metals production; automobile and truck exhaust; home heating;
and the overtilling of dry-area farmland.
While releases
of one key type of aerosol, sulfur dioxide, have been decreasing
in the United States and Europe since tough air-pollution rules
were enacted, the releases are increasing in Asia, particularly
in China, Cahill said. Between 1990 and 2000, annual releases
of sulfur dioxide into the atmosphere in the United States dropped
from about 20 million tons to 13 million tons, but in China they
have climbed to about 45 million tons.
Once released
into the air, aerosols ride the wind over land and sea, rising
to altitudes of several miles, where their travel is sped by
the dry atmosphere and swift winds. Wherever they go, they retain
a unique signature of their origins in their composition of trace
elements, such as nickel, copper, zinc, arsenic and lead. Aerosols
with these unique signatures from Asia have been detected all
the way to the US Rocky Mountains, Cahill said.
The new data
are the first results of a research project named the University
of California Pacific Rim Aerosol Network, which was started
in 1998 with $67,000 from the university system. Cahill said
he expects the findings to suggest more Asian impacts.
Cahill also
described the network's planned role in the large, multimillion-dollar
ACE-Asia international research program. In ACE-Asia, the existing
air samplers and some additions will gather data for six weeks
in spring 2001. New samplers will be installed at sites in five
Asian countries (China, Taiwan, the Philippines, South Korea
and Japan), Mexico and the United States.
The heart
of the network is the newly designed International Aerosol Sampler,
which was designed and built at UC Davis. It is inexpensive,
lightweight and low-tech for producing reliable data in undeveloped
regions with unreliable power supplies. It collects air samples
that can be chemically checked for unique signatures and tracked
as they move around the globe. This method of developing chemical
signatures has been put to intensive use at UC Davis since the
early 1970s, when Cahill and colleagues were conducting the first
studies to identify the origins of view-blocking haze in US national
parks.
Those land-based
machines will collect data in synchronization with aerosol detectors
aboard ships, airplanes and satellites, Cahill said. The US National
Science Foundation has granted UC Davis $350,000 over three years
for its part of the ACE-Asia project.
After the
ACE-Asia work concludes, the UC network will continue to deliver
critical information, Cahill said. "The relationship between
a smelter in Manchuria and aerosol pollution in Japan is not
obvious. That's the understanding we're trying to achieve,"
he said. 
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ucdavis.edu, (530) 752-7704.