WASHINGTON – From 500 miles up in space, satellites track brown clouds of dust, soot and other toxic pollutants from China and elsewhere in Asia as they stream across the Pacific, taking dead aim on the Northwest and the rest of the Western United States.
A fleet of tiny, specially equipped unmanned aerial vehicles, launched from an island in the East China Sea 700 or so miles downwind of Beijing this summer, is flying through the projected paths of the pollution, taking chemical samples and recording temperatures, humidity levels and sunlight intensity in the clouds of smog.
On the summit of 9,000-foot Mount Bachelor in Central Oregon and near sea level at Cheeka Peak on the Olympic Peninsula, monitors track the pollution as it arrives onshore.
By some estimates more than 10 billion pounds of airborne pollutants from Asia – ranging from soot to mercury to carbon dioxide to ozone – reach the United States annually. The problem is expected to worsen as some Chinese officials have warned that pollution in their country could quadruple in the next 15 years if not curbed.
While some scientists are skeptical, others say the Asian pollution could destabilize weather patterns across the North Pacific, mask the effects of global warming, reduce rainfall in the American West and compromise efforts to meet air pollution standards in the United States.
“East Asia pollution aerosols could impose far-reaching environmental impacts at continental, hemispheric and global scales because of long-range transport,” according to a report earlier this year in the Journal of Geophysical Research. The report said that a “warm conveyor belt” lifts the pollutants into the upper troposphere over Asia, where winds can wing it to the United States in a week or less.
The National Academies of Science, at the request of the Environmental Protection Agency, NASA and the National Oceanic and Atmospheric Administration and in consultation with the State Department, has assembled a special panel to look at the problem and its impact. Its report is due next summer.
“Everyone realizes this is an issue of growing importance,” said Laurie Geller of the National Academies of Science. “This is very challenging science with lots of complexities and a lot of uncertainties.”
Though the problem of Asian air pollution has been known for 10 years, no one has an exact handle on how much actually is blown in and what it includes. Scientists say Washington state and Oregon might be feeling the brunt of the effects.
“This pollution is distributed on average equally from Northern California to British Columbia,” said Dan Jaffe, a professor of environmental science at the University of Washington’s Bothell campus. “Anyone who has gone out to measure it has found something.”
Particulates including dust and soot, along with heavy metals, pesticides, PCBs, mercury, ozone, carbon dioxide, nitrogen dioxide and sulfur dioxide, have all been found. Jaffe said the pollutants can’t be tracked to a single source such as a particular coal-burning plant, but their “chemical fingerprints” can point to a specific country.
Viruses, bacteria and fungi also can be transported on dust particles, though so far they’ve been found on only the dust and sand blowing off African deserts, not Asian ones.
Mercury, one of the most hazardous pollutants from the hundreds of coal-burning electricity plants in China and elsewhere in Asia, is of particular concern. One study estimated one-fifth of the mercury entering Oregon’s Willamette River comes from overseas, with China the mostly likely source.
Jaffe, a member of the National Academies of Science panel studying the issue, remains wary of such reports. But he still estimates that up to 30 percent of the mercury deposited in the United States from airborne sources comes from Asia, with the highest concentrations in Alaska and the Western states.
On the worst days, Jaffe said, more than one-third of allowable ozone levels in the United States are Asian in origin, along with 50 percent of the allowable particulate levels. Ozone is a respiratory irritant, and particulates can cause severe respiratory and cardiovascular problems.
“Ten years ago, there was a lot of skepticism,” Jaffe said. “People assumed the atmosphere scrubbed itself and didn’t believe these pollutants could travel thousands of miles.”
The pollution from Asia will make it increasingly difficult for the United States to meet stricter and stricter air quality standards, said Lyatt Jaegle, a professor of atmospheric sciences at the University of Washington.
“It is only expected to get worse,” Jaegle said of the Asian air pollution reaching the United States. He added that scientists have discovered that the problem isn’t unique to the Pacific Rim.
“Air pollution is not a local or regional problem, it is a global problem,” he said.
Days after a major dust storm in the Gobi Desert in Asia, visibility in the Grand Canyon was obscured. Dust from deserts in North Africa has reached Florida. U.S. air pollution can reach across the Atlantic to Europe, even as pollution from Europe can circle the globe and reach the United States.
Air can circulate around the world in three weeks or less. The National Academies of Science isn’t limiting itself to pollution from Asia and will study the phenomenon worldwide.
“It’s one atmosphere,” said Mark Schoeberl, project scientist for NASA’s Aura satellite program.
GLOBAL DIMMING, TOO
Schoeberl said his and other satellites have “transformed” what scientists know about the Earth and can provide a near-real-time snapshot of the track of airborne pollution. When gasoline production spikes, Jaffe said, satellites can detect an increase in sulfur dioxide levels at Saudi Arabian refineries. They’ve also helped confirm global dimming as sunlight reaching the planet’s surface is decreasing because the airborne pollution reflects it back to space. In some places, such as Israel, sunlight has decreased 10 percent, Jaffe said.
The pollution also can mask the effect of global warming by reflecting the sunlight, said Veerabhadran Ramanathan, a climate researcher at the Scripps Institution of Oceanography in California who heads the team of scientists flying the unmanned vehicles off Korea this summer.
The UAVs started flying as China shut down factories and banned automobiles from Beijing during the Summer Olympics. They’re still flying as pollution levels again increase.
“It’s a once-in-a-lifetime opportunity,” Ramanathan said.
The reduction in sunlight could be increasing rainfall or it might be decreasing rainfall because of less evaporation off the ocean, Ramanathan said. In addition, the soot falling on mountains in the Western United States could increase snowmelt, he said.
“There are a lot of questions and few answers,” Ramanathan said. “We shouldn’t be pointing fingers. Everyone else is someone else’s backyard. This is a global problem.”
Les Blumenthal: 202-383-0008