Scientists Study Beijing's "Olympic" Air Pollution

When Chinese officials ban two million cars from Beijing during the Olympics, researchers will be measuring the air.

April 21, 2008
By Emilie Lorditch
Inside Science News Service

COLLEGE PARK, MD -- As athletes from around the world are beginning their final training for the summer Olympic Games in Beijing, scientists from China and the United States are making final preparations to study the impact of air pollution controls on Beijing’s notoriously bad air quality during the games.

Air pollution in Beijing is significant and the International Olympic Committee’s medical commission recently said “there may be some risk” to the athletes from the bad air. Indeed, IOC chairman Arne Ljungqvist said, “It may be that some events will not be conducted under optimal conditions.” He noted that, “we may not see records broken in Beijing,” as a result of the air pollution.

China’s scientific response is the Campaigns of Air Quality Research in Beijing (CAREBEIJING) project. It is “by far the largest air quality research campaign in China,” said Tong Zhu, a professor of environmental sciences at Peking University in Beijing and a member of the pollution monitoring project. “The findings from the project bring long-term improvement of air quality for the residents in Beijing and surrounding regions.”

In 2006, members of the CAREBEIJING project identified vehicle emissions as one of the major contributors to Beijing’s air pollution, and in 2007 they put the number of vehicles traveling on Beijing’s roads at more than three million. To get an idea of how much pollution was coming from vehicles, officials working with the project instituted a vehicle-restriction program that would keep vehicles off the roads.

For four days in August, 2007, 1.3 million vehicles were not allowed on the city’s roads. “We measured the main pollutants emitted by vehicles: nitrogen oxide, carbon monoxide, and volatile organic compounds,” said Zhu.

Using satellite, aircraft, and ground measurements, the research team determined what impact the reduction in vehicle emissions had on overall air quality. The results were significant, with satellite measurements of nitrogen oxide showing a reduction between 17 and 50 percent, while ground-based measurements showed carbon monoxide was reduced by about 22 percent, and volatile organic compounds were reduced by between 20 and 30 percent.

Based on the success of this small-scale test, Zhu said he will recommend even tighter vehicle restrictions during the Olympic Games, which begin August 8th. “During the Olympic games, two million vehicles will be restricted from the roads,” said Zhu. He contends that, “with all the controlling measures that are taking place, the air quality will be improved significantly and won’t affect visiting athletes and spectators.”

Scientists from the United States are joining the Chinese researchers in studying the impact of the vehicle restrictions on pollution. Beginning in June, V. Ramanathan, an atmospheric and climate scientist at Scripps Institution of Oceanography, and his team will use four unmanned aircraft equipped with instruments launched from South Korea's Cheju Island to measure the air pollution downwind of Beijing.

The real-time aircraft data will be combined with satellite data and ground observations from China to give a more complete air quality picture. This mission will last through September, so scientists will have pollution data from before, during, and after the Olympic Games vehicle restrictions.

Although Ramanathan’s team will be able to compare the changes in air pollution levels related to the restrictions, they are specifically looking at atmospheric brown cloud (ABC), a phenomenon made up of all pollutants that can affect rainfall, cloud formation, and air temperatures. Because of the long, dry seasons, ABC is more persistent in Asia and India, but can also be found in Los Angeles.

“By flying two unmanned aircraft at the same time at different altitudes -- one above the ABC and one below it -- we can get a cross-section of the atmosphere,” Ramanathan said. “Then, we can fly one of the aircraft inside the ABC, which will give us a cross-section of the cloud.”

By adding data from the study to computer models, he said, “we are hoping to learn more about ABCs and the aerosol/monsoon interaction. This happens at a larger scale in China with southern China experiencing flooding, while northern China has drought conditions.”

The Olympic Games helped Ramanathan open the lines of communication with China’s researchers, he said. “We would have done this even without the Olympics, but the games have given us a big opportunity.”

Although Beijing is infamous for its high levels of pollution, Ramanathan said the international political disputes over pollution are counterproductive. “Instead of blaming North America, Europe, or Asia as the source of air pollution, we need to stop pointing fingers and everyone needs to work together,” he said.

Emilie Lorditch is a writer for the Inside Science News Service, and is the senior science editor for the American Institute of Physics’ Discoveries and Breakthroughs Inside Science television programming.

***This story is provided free for media use by the Inside Science News Service, which is supported by the American Institute of Physics, a not-for-profit publisher of scientific journals. Please credit ISNS. Contact: Jim Dawson, news editor, at jdawson@aip.org.