Source: 科学与发展网络 (SciDev.Net)
6 August 2008 | EN | 中文
Smog around the 'bird's nest' Beijing National stadium
Chinese action on Olympic air pollution is a huge experiment that will be closely watched across China, and further afield, writes Wang Ying.
As the 2008 Beijing Olympic Games get underway, an expensive environmental experiment is taking place, providing a golden opportunity for pollution science.
The Beijing Olympic Air Quality Monitoring and Warning Project, a 30 million yuan (US$4.3 million) monitoring system, has been created in an attempt to guarantee clear skies for the games.
Jointly launched by the Beijing municipal government and the Chinese Academy of Sciences (CAS), the system has been fully active since June. It has 25 comprehensive air quality monitoring stations and several mobile surveillance vehicles in Beijing and adjacent cities.
Beijing's air quality has been unpalatable to some athletes. Back in May, the marathon world record holder Haile Gebrselassie, who suffers from asthma, confirmed that he would skip the games for fear of Beijing smog. And in June, Australian officials said their track and field athletes will not participate in the opening ceremony, partly because of pollution problems.
But Chinese scientists say the monitoring is providing ways to improve air quality, in the short term at least.
China's pollution problem
China has been monitoring air quality since the 1950s. But in the late 1990s, air quality worsened and respiratory disease increased, triggering attempts to tackle the problem.
Ten cities, including Beijing, Shanghai and Tianjin, started issuing daily air quality reports in 1998.
Each year, China sees 350,000 cases of respiratory diseases, such as asthma and bronchitis, due to urban air pollution. The Chinese Centre for Disease Control and Prevention estimates this costs around seven per cent of the country's annual gross domestic product.
Jin Yinlong, an official with the centre, says that although the country's air quality has recently improved, urban air pollution "remains serious".
In 2006, 37.6 per cent of China's 559 major cities did not meet national air quality standards.
"Beijing's major pollutants — nitrogen oxides, sulphur dioxide, suspended particulate matter (dust less than ten micrometres diameter), ozone and carbon monoxide — come from vehicle exhaust, factories, and construction sites, and volatile organic compounds (VOCs) mainly come from gas stations," says Wang Yuesi, a researcher with CAS's Institute of Atmospheric Physics.
"Vehicle emissions contribute 60 to 70 per cent of air pollution in Beijing, and these pollutants usually stay in the air for three to four days," Wang adds.
When Beijing was awarded the 2008 Olympics in 2001, the city's air pollution came under further scrutiny.
When Beijing was awarded the 2008 Olympics in 2001, the city's air pollution came under further scrutiny
The Beijing Municipal Government pledged a green Olympics to the International Olympic Council. Under that commitment, concentrations of sulphur dioxide, nitrogen dioxide and ground-level ozone should meet WHO recommended levels for air quality, and dust concentrations should be comparable to levels in major cities in developed countries.
Beijing's environment authorities, including the Beijing Environmental Protection Bureau, have taken steps to rapidly cut pollution levels.
They ordered 19 heavily polluting industries to cut emissions by 30 per cent, and closed large factories in major pollution source areas, such as the Yanshan petrochemical zone and around the Beijing Capital International Airport.
They stopped quarrying operations and suspended construction projects on windy days. Coal-burning industries have been relocated permanently outside of built-up areas.
Beijing's traffic also faces strict controls. An 'even-and-odd' licence plate rule, implemented three weeks before the games open, lets drivers use their cars only on alternate days.
A trial of the system last summer pulled 1.3 out of the city's three million cars off the roads each day, reducing pollutants by 17–28 per cent.
Poised for action
Beijing environment officials have vowed to publish air quality forecasts up to a week in advance during the games.
"If air pollution is to reach an alarming level, often triggered by extreme weather conditions, such as high temperatures, high humidity and no wind, emergency plans will start, including pulling more cars off road or shutting down more factories," says Liu Jianguo a scientist on the air quality project, and deputy director of CAS's Key Laboratory of Environmental Optics and Technology.
Beijing has 40 ground-level air quality monitoring stations able to measure up to an altitude of ten metres, and the 25 comprehensive monitoring stations in the Olympic Air Quality Project can measure pollution up to five kilometres.
The higher elevation monitoring lets scientists trace pollutants from neighbouring cities, as well as local sources.
Wang Yuesi explains that the weather and geographical conditions both in Beijing and nearby areas control how regional air pollutants accumulate and disperse, particularly in the summer.
Winds from the south and southeast sweep through Beijing in summer. They blow pollutants to the north and northwest, where the mountains slow down their spread, letting them descend upon the city.
By measuring the amount of pollutants floating into Beijing at its outskirts, CAS scientists estimated in June that 30 per cent of the capital's pollutants come from nearby cities.
A CAS technician checks air monitoring data in a Beijing monitoring site
Now, Bejing's neighbouring areas — such as the provinces of Tianjin, Hebei, Shanxi, Shandong and Inner Mongolia — are helping out by closing factories and removing highly polluting cars.
Beijing is also seeking advice from further afield. A 12-member panel on air quality assessment, including three foreign experts, will help monitor air quality during the Games.
Du Shaozhong, deputy director of the Beijing Environmental Protection Bureau, says involving foreign experts ensures authority and transparency in air quality monitoring and forecasting.
Ivo Allegrini, a member of the panel and head of the air pollution department at the Italian National Research Center, told SciDev.Net he will be leading an Italian team working in Beijing throughout August, beyond the two weeks of the games. His team will receive data from the Environmental Protection Bureau and will also conduct independent monitoring.
The latest technology
The techniques being used during the Olympics showcase China's latest monitoring technologies that can now measure air quality out in the field, as well as air samples in the laboratory.
Ultraviolet and infrared radiation spectroscopy technologies help to monitor trace gases in the atmosphere. To study the correlation between pollutants and traffic, microwave radars have been installed at main roads in Beijing to count the vehicles on the road each hour.
Meteorological instruments also measure temperature, humidity, air pressure, wind speed and direction, to better understand how pollutants spread in different weather conditions.
And much of the equipment used is produced in China for China's needs.
"About 70 per cent of the devices used in the [monitoring] network were developed domestically, including the equipment that measures pollutants such as nitric oxide, carbon monoxide, methane, ammonia and VOCs," says Liu Wenqing, a member of an expert panel for China's National High-Tech Programme, which has earmarked several million dollars annually for environment projects.
But Liu says more could be done, pointing out that China has launched dozens of satellites, but not one has been used for air quality monitoring. Instead, China uses foreign satellite data. Yet the United States and some European countries, such as the United Kingdom, have used remote sensing satellites for air quality monitoring since 1995.
"We do not lack talents or technology, but policy support," says Liu.
China also lacks the large-scale monitoring equipment that can provide more accurate data, and the equipment to deal with extreme air pollution emergencies, such as an explosion at a chemical factory or a major gas leakage, Liu adds.
Further afield and the future
As the Olympics approach, scientists are watching closely to see how effective pollution control will be, both for Beijing and beyond.
US scientists believe that as much as 25 per cent of the air pollution in Los Angeles comes from China. An article in the Los Angeles Times stated, "When the Chinese undertake this enormous change in their emissions, it will send a signal to the United States that the control of air pollution in one part of the world can in fact affect the atmosphere on the other side of the globe".
Scientists are watching closely to see how effective pollution control will be, for Beijing and beyond
"The scientific community should plan immediately to take advantage of this monumental experiment, mobilising to measure the effect by studying pollution levels before, during and after the great shutdown," the article reads.
Los Angeles itself took radical measures to cut smog in 1984 when it hosted the Olympics, forcing political leaders to tackle the issue.
Chinese scientists hope for a similar effect. The monitoring area for the Olympics includes 79 cities in the greater Beijing area and CAS is looking to expand this network in the long run, including to the two city clusters of Guangzhou and Shanghai.
CAS has already begun cooperating with Guangzhou and Shanghai to promote regional air quality management. The Beijing experience will be particularly useful since Shanghai will host the 2010 World Expo and Guangzhou will host the 2010 Asian Games.
In April, CAS signed a contract with the Beijing municipal government to jointly tackle Beijing's long-term air pollution. The city's five-year environmental plan (2005–10) aims to cut major air pollutants by 20 per cent of 2005 levels and develop an environmental management system in Beijing and nearby cities.
All eyes are on China, for the Olympics and beyond.
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