20080317-pollution over east China NASA.jpg
Pollution over east China
Chinese pollution is not just a local phenomena but also a regional and global one. During the spring there are fierce dust and sand storms in the Gobi desert and northern and western China. As the dust and sand are blown eastward by westerly winds, they pick up air pollution particles, especially over heavily industrialized areas in northeast China like Shenyang, and carry them further east into to South Korea and Japan and further east. A group called Project Asia Brown Cloud — using aircraft and ground stations in China, South Korea and Japan — have observed that clouds of industrialized pollution that originate in Shenyang, and merging with dust and sand clouds that originate in the Gobi Desert and Xinjiang

Across large swath of Asia, especially in China, you can find two-mile-thick blankets of sulfates, soot, organic compounds, dust, fly ash and other materials. Particularly worrisome is airborne mercury, a dangerous toxin released from coal-burning power and industrial plants. According to emission researchers, half the world’s man-made mercury emissions come form Asia, with China being the main source.

By some estimates China accounts for between 25 percent and 28 percent of global mercury emissions. Mercury can accumulate in the atmosphere and travel thousands of kilometers before being brought to earth by rainfall. Some of its ends up in water where it enters the food chain and accumulates in fish that are sometimes eaten by people. Acid from Chinese industrial air pollution has been blamed for damaging trees in the mountains of northern Japan. Much of is from factories in the coal-rich areas of Shanxi Province.

People in Korea and Japan complain that acid rain that falls on them is created by emissions of sulfur and nitrogen oxides from coal-burning plants in northern China. South Koreans and Japanese also complain that the winds that carry the sulfur and nitrogen oxides also pick up heavy metals and carcinogens and dump them in their countries. Deaths attributed to yellow-sand-caused cardiovascular and respiratory diseases have been reported in South Korea. Some schools in Japan and South Korea have reduced their activities because of pollution and yellow dust from China.

The Japanese professor Fumitaka Yanagisawa said that when he presented a paper at a Chinese university that suggested some pollution in Japan originated in China he was booed by the audience and said “even now it’s sort of taboo to mention cross-border pollution when I’m invited to give a speech in China.” Reiko Sodeno, of the Japanese environmental ministry, told AFP, “It will have adverse affects if we push China too much on cross-border pollution...Blaming other countries wouldn’t help to solve the problem, as it only hurts national pride.”

Chinese Air Pollution Reaches the United States

Increasing amounts of pollution are being blown across the Pacific Ocean to North America. Pollutants carried by the jet stream can reach the United States in days. Pollutants from Asia reaching the United States are rising at a rate of 5 percent to 10 percent a year. On some days, almost 25 percent of the pollutants in the air above Los Angeles originated in China, the Environmental Protection Agency has found. American heath officials find this figure alarming when is tacked onto pollution that already exist in the United States.

Increases in amounts of ozone and fine particulate matter found in the air in the United States is blamed on “transpollution” from China. Scientists estimate that in 2010, on third of the ozone in Los Angeles will originate in Asia, much of it in China. Asian soot has been blamed for speeding up the thinning of Arctic ice and other polar environmental changes.

Soot, dust and chemical pollutants from China have been captured in a weather observation stations on the summit of Mount Bachelor in Cascade Range in Oregon. Soot, dust, ozone and nitrous oxides can be detected by satellites moving across the Pacific. But just as the Americas worry about air pollution from Asia, Europeans worry about pollution carried by winds from the Americans and Asians worry about pollution carried by winds from Europe.

David Kirby wrote in Discover magazine, “The biggest pollutant coming out of Asia, at least in terms of sheer mass, could be dust from the region’s swelling deserts. Chinese dust has obscured vistas in U.S. national parks, even on the East Coast. The amount of dust is widely variable and can hit rare extreme peaks. The highest level recorded was from a 2001 dust event. One report found it “reached approximately two-thirds of the U.S. air quality standard at several sites along the West Coast.” One study from Taiwan tracked avian flu outbreaks downwind of Asian dust storms and found that the flu virus might be transported long-distance by air spiked with the dust. [Source: David Kirby, Discover magazine, March 18, 2011]

“It’s not a new phenomenon,” University of Washington atmospheric chemist Dan Jaffe told Discover, but it has gotten worse with deforestation and desertification caused by poorly managed agriculture. About every three years, a huge dust storm over China sends enormous clouds across the Pacific. “We can visually see it,” Jaffe says. “It usually hangs around for about a week. We’ve tried to quantify how much it contributes to the particulate loading here, and it’s a little under 10 percent of the U.S. standard on average each year. It’s a significant amount.”

Studying Chinese Air Pollution Traveling Abroad

In the 1990s University of Washington atmospheric chemist Dan Jaffe began asking: Could pollution reaching the West Coast of the United States be blowing in from somewhere else? “We had a hunch that pollutants could be carried across the ocean, and we had satellite imagery to show that,” Jaffe he told Discover magazine. “And we noticed our upstream neighbors in Asia were developing very rapidly. I asked the question: Could we see those pollutants coming over to the United States?”

At that time scientists considered it improbable that a concentration of pollutants high enough to significantly impact American air quality could travel thousands of miles across the Pacific Ocean; they expected he would find just insignificant traces. David Kirby wrote in Discover magazine, “Despite their skepticism, Jaffe set out to find the proof. First he gathered the necessary equipment. Devices to measure carbon monoxide, aerosols, sulfur dioxide, and hydrocarbons could all be bought off the shelf. He loaded the equipment into some university trucks and set out for the school’s weather observatory at Cheeka Peak. The little mountain was an arduous five-hour drive northwest of Seattle, but it was also known for the cleanest air in the Northern Hemisphere. He reckoned that if he tested this reputedly pristine air when a westerly wind was blowing in from the Pacific, the Asian pollutants might show up. [Source: David Kirby, Discover magazine, March 18, 2011]

Jaffe’s monitors quickly captured evidence of carbon monoxide, nitrogen oxides, ozone, hydrocarbons, radon, and particulates. Since air from North America could not have contaminated Cheeka Peak with winds blowing from the west, the next step was identifying the true source of the pollutants. Jaffe found his answer in atmospheric circulation models, created with the help of data from Earth-imaging satellites, that allowed him to trace the pollutants’ path backward in time.” A paper he published two years later summarized his conclusions succinctly. The pollutants “were all statistically elevated . . . when the trajectory originated over Asia.”

Officials at the U.S. Environmental Protection Agency took note, and by 1999 they were calling Jaffe to talk. They were not calling about aerosols or hydrocarbons, however, as concerning as those pollutants might be. Instead, they were interested in a pollutant that Jaffe had not looked for in his air samples: mercury (See Below).

Asian Ozone and Sulfates Traveling Abroad

David Kirby wrote in Discover magazine, “Perhaps the most counterintuitive traveling contaminant is ozone, commonly associated with ground-level pollution in cities. Volatile organic compounds, carbon monoxide, and nitrogen oxides from Asian cars and industry mix in the atmosphere as they cross the Pacific Ocean and convert in sunlight into ozone, a main ingredient in smog, Jaffe explains. When air with high ozone concentrations touches down in North America, it can pose the classic dangers of urban smog: heart disease, lung disease, and death. [Source: David Kirby, Discover magazine, March 18, 2011]

Jaffe has coauthored a paper on Asian ozone coming to America. It found that ozone levels above western North America creep upward every spring. “When air was coming from Asia, the trend was strongest. That was the nail in the coffin,” Jaffe told Discover. “The increase was estimated at 0.5 part per billion [ppb] per year. But that’s huge. In 10 years that’s another 5 ppb. Let’s say the epa orders a 5 ppb reduction and we achieve that, and yet, because of the growing global pool, in 10 years that gets wiped out. We’ll have to keep reducing our emissions just to stay even.”

Over the years, at Mount Bachelor, a ski resort in central Oregon with an altitude of 9,000 feet, Jaffe has monitored many other noxious pollutants wafting across the Pacific. One major category is sulfates, associated with lung and heart disease. When sulfur dioxide exits China’s coal and oil smokestacks, it converts into sulfates in the air. “Sulfates are water-soluble and get removed from the atmosphere relatively quickly, creating acid rain that falls in China, Korea, and Japan,” Jaffe says. Yet some of the sulfates stay aloft, finding their way here and contributing to smog along the West Coast.

Global Circulation of Air Pollution

David Kirby wrote in Discover magazine, “The underlying message of Jaffe’s detective work should not be all that surprising: All of the world’s atmosphere is interconnected. People have accepted this notion when it comes to carbon dioxide or the chemicals that eat away at the ozone layer, but Jaffe is finding that they are still coming to terms with the reality that it applies to industrial pollutants in general.” [Source: David Kirby, Discover magazine, March 18, 2011]

“The fact is, those pollutants are everybody’s responsibility, not just China’s. The EPA has estimated that just one-quarter of U.S. mercury emissions from coal-burning power plants are deposited within the contiguous U.S. The remainder enters the global cycle. Conversely, current estimates are that less than half of all mercury deposition within the United States comes from American sources.”

“Then again, the United States has spent considerable effort over the past half-century trying to clean up its act. China is still much more focused on production. To fuel its boom, China has become a pioneer in wind power but has also begun buying up huge inventories of coal from markets around the world. Streets recently estimated that China’s use of coal for electricity generation will rise nearly 40 percent over the next decade, from 1.29 billion tons last year to 1.77 billion tons in 2020. That is a lot more pollution to come.”

“It’s a classic example of a tragedy of the commons,” Jaffe told Discover, referring to a dilemma in which individuals act in their own self-interest and deplete a shared resource. “If 20 people are fishing in the same pond, with no fishing limit, then you catch as many as you can because it will be empty in weeks. Nobody has an incentive to conserve, and the same goes for pollution. “

Mercury Pollution in China

China now emits more mercury than the United States, India, and Europe combined. Mercury is a common heavy metal, ubiquitous in solid material on the earth’s surface. David Kirby wrote in Discover magazine, “China is full of the two biggest contributors to human-generated mercury, metal smelting and coal combustion. Smelting facilities heat metal ores to eliminate contaminants and extract the desired metal, such as zinc, lead, copper, or gold. Unfortunately, one of the consistent contaminants is mercury, and the heating process allows it to escape into the atmosphere in gaseous form. Similarly, coal contains trace amounts of mercury, which is set free during combustion at power plants. While it is trapped it is of little consequence to human health. But whenever metal is smelted or coal is burned, some mercury is released. It gets into the food chain and diffuses deep into the ocean. It eventually finds its way into fish, rice, vegetables, and fruit. [Source: David Kirby, Discover magazine, March 18, 2011]

“When inorganic mercury (whether from industry or nature) gets into wet soil or a waterway, sulfate-reducing bacteria begin incorporating it into an organic and far more absorbable compound called methylmercury. As microorganisms consume the methylmercury, the metal accumulates and migrates up the food chain; that is why the largest predator fish (sharks and swordfish, for example) typically have the highest concentrations. Nine-tenths of the mercury found in Americans’ blood is the methyl form, and most comes from fish, especially Pacific fish. About 40 percent of all mercury exposure in the United States comes from Pacific tuna that has been touched by pollution.”

In pregnant women, methylmercury can cross the placenta and negatively affect fetal brain development. Other pollutants that the fetus is exposed to can also cause toxic effects, “potentially leading to neurological, immunological, and other disorders,” says Harvard epidemiologist Philippe Grandjean, a leading authority on the risks associated with chemical exposure during early development. Prenatal exposure to mercury and other pollutants can lead to lower iq in children — even at today’s lower levels, achieved in the United States after lead paint and leaded gasoline were banned.

Studying Mercury Pollution in China

David Streets, a senior energy and environmental policy scientist at Argonne National Laboratory in Illinois, was on the forefront of the study of acid rain in the 1980s and carbon dioxide and global warming in the 1990s. In the mid 1990s he began focusing on emissions from China and has since become such a noted expert that he helped the Chinese government clean up the smoke-clogged skies over Beijing before the Olympics in 2008.

David Kirby wrote in Discover magazine, “In 2004, spurred by increased attention to mercury in the atmosphere, Streets decided to create an inventory of China’s mercury emissions. It was a formidable undertaking. Nobody had ever come up with a precise estimate, and the Chinese government was not exactly known for its transparency. Streets began by studying reports from China’s National Bureau of Statistics. China’s provinces provide the central government with detailed data on industrial production: how much coal they burn, how much zinc they produce, and so on. “China is very good at producing statistical data. It’s not always 100 percent reliable, but at least it’s a start,” he says. Those statistics help the Chinese government monitor the economy, but for Streets they also quantified China’s mercury-laden raw materials.” [Source: David Kirby, Discover magazine, March 18, 2011]

“The numbers from the statistics bureau told Streets the total amount of mercury that might be emitted, but he also needed to know how much actually made it into the air. To obtain that information, he turned to pollution detectives — a group of professional contacts he had met at conferences, along with graduate students who spent time in his lab. Most of the time, Chinese factories turned these “spies” away. “Factory owners had nothing to gain and a lot to lose,” Streets says. “They were nervous that the results would get leaked to the government.” Yet some of Streets’s moles got through by guaranteeing that the data would stay anonymous. Once inside, they took samples of raw materials — zinc ore in a smelting facility, for example — and installed chemical detectors in smokestacks. After a few days of data collection, they passed the information to Streets.”

The statistics Streets collected were hardly airtight. Factory foremen and provincial officials were not above providing inflated data to make themselves look more productive, and the managers who were willing to let his inspectors take measurements were often the very ones with nothing to hide. “There’s still a lot of uncertainty,” Streets concedes, “but we know more than we did before.”

In 2005 Streets and his team reported their first tally of human-generated mercury emissions in China, for the year 1999. The scientists estimated the amount at 590 tons (the United States emitted 117 tons). Almost half resulted from the smelting of metals — especially zinc, because its ores contain a high concentration of mercury. Coal-burning power plants accounted for another 38 percent of Chinese mercury emissions, and that percentage may be going up. As recently as 2007, China was building two new power plants a week, according to John Ashton, a climate official in the United Kingdom. Streets’s team published a subsequent inventory estimating that China’s mercury emissions had jumped to 767 tons in 2003. “Mercury emissions in China have grown at about 5 to 6 percent a year,” he says. “It’s pretty much undeniable.”

Image Sources: NASA

Text Sources: New York Times, Washington Post, Los Angeles Times, Times of London, The Guardian, National Geographic, The New Yorker, Time, Newsweek, Reuters, AP, Lonely Planet Guides, Compton’s Encyclopedia and various books and other publications.

Last updated July 2011

This site contains copyrighted material the use of which has not always been authorized by the copyright owner. Such material is made available in an effort to advance understanding of country or topic discussed in the article. This constitutes 'fair use' of any such copyrighted material as provided for in section 107 of the US Copyright Law. In accordance with Title 17 U.S.C. Section 107, the material on this site is distributed without profit. If you wish to use copyrighted material from this site for purposes of your own that go beyond 'fair use', you must obtain permission from the copyright owner. If you are the copyright owner and would like this content removed from, please contact me.