Special Reports
Trans-pacific Air Pollution Is Worse Than Was Suspected

University of California - Davis

UC Davis researchers will report today 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.

Besides releasing these first results of the University of
California Pacific Rim Aerosol Network, the researchers will
also describe 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

"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

"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.

Cahill and his research collaborators will present their data
today at the First International Conference on Trans-Pacific
Transport of Atmospheric Contaminants, which runs Thursday
through Saturday at the Aljoya Conference Center in Seattle,
Wash. The UC Davis researchers are Cahill; Peter Kelly, an
associate professor of chemistry; Steven Cliff, a postdoctoral
research scientist; and Michael Jimenez-Cruz, manager of the
DELTA group laboratory, all of whom who comprise UC Davis'
DELTA research group (for Detection and Evaluation of
Long-Range Transport of Aerosols). They are joined by Tony
VanCuren, a research scientist for the California Air
Resources Board; and Kevin Perry, a professor of meteorology
at San Jose State University.

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 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 U.S. 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 at this week's invitation-only conference, which
will be attended by about 100 experts.

Cahill will also describe 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 U.S. national

Those land-based machines will collect data in synchronization
with aerosol detectors aboard ships, airplanes and satellites,
Cahill said. The U.S. 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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