Nearly half the vehicles in Beijing will be ordered off the roads during the "Good Luck Beijing" sports events to test the city's air quality. Test results will be used to revise the Olympic Air Quality Guarantee Scheme.

In an interview with the Beijing News on August 9, Ms. Tang Xiaoyan, an expert invited for the drafting of this scheme, member of the Chinese Academy of Engineering, professor at Peking University, and scientific advisor for the Beijing municipal government, talked about this air quality test and traffic restrictions during the Olympic test events.

The Beijing News (BN): Beijing has ordered some vehicles off the roads to test the air quality. How important is air quality to the Olympics?

Tang Xiaoyan (Tang): Since 1998, Beijing has taken measures to control air pollution, and air quality has consequently improved. For next year's Olympics, air quality is of the utmost importance to the athletes. The key issue is to prevent high concentrations of air pollutants.

BN: In which aspects will air pollutants be highly concentrated?

Tang: Take inhalable particles for example. This kind of pollutant contains many small particles which cause atmospheric visibility to decline. The particles consist of even smaller particulates, their size ranging from nano to micrometer. They can enter into the human body very easily, and if they get into the respiratory tract, or even the lungs, respiration might be affected. So air quality must be guaranteed for the sake of the athletes.

BN: Has air quality been taken into consideration in Beijing's bid for the Olympics?
Tang: In its bid for the Olympics, Beijing promised to keep air quality in line with national standards and try to meet WHO requirements.

Last year, the Beijing municipal government invited a group of experts to carry out research on air quality during the Olympics. They have studied the desirable standards, goals, as well as measures to be taken. An Olympic Air Quality Guarantee Scheme has been submitted to the municipal government, covering the city itself as well as its surrounding areas.

BN: What pollution controls are covered in the Scheme?

Tang: It includes controls on coal burning, industrial emissions, vehicle emissions, and raised dust.

BN: What can we expect from this Scheme?

Tang: This Scheme was made based on our past practices. Predictions have been made about what will happen next year, but it's still not clear what the level of success will be. We hope to have an opportunity to test it, even just for a small part. We want to see if it can really meet the requirement of air quality standards during the Olympics next year.

We suggested that the municipal government should test a certain part or parts of the Scheme during the Olympic test events. As a result, the government decided to conduct a test from August 17 to 20, 2007. It can be considered as an exercise for this Scheme.

BN: Do you think 4 days' time is enough?

Tang: We were expecting a longer time for a better effect. But we were afraid that it might affect other work in the city. The municipal government has given us 4 days: a Friday, a weekend and a Monday. Friday and Monday are the busiest weekdays. We hope to see this Scheme's practical effect.

BN: As you have mentioned, the Scheme includes various pollution controls, so why does this test only focus on vehicle emissions?

Tang: It's because vehicles are the biggest inhalable particulate emitters, and the leading cause of particle pollution. It impacts significantly the visibility in the air and people's health. Moreover, the primary pollutants emitted by the vehicles will be converted to cause secondary pollution in the air. So, the whole Scheme's success depends largely on the vehicles emissions control. Other pollutants will be attended to later on.

BN: What air quality test will be conducted at that time?

Tang: We've set up some monitoring stations, and our work will be divided into three phases: first, from August 1 to 17; second, from August 17 to 20, when the drill is being applied; third, from the August 20 to the end of August. We'll collect the data of these phases respectively, do the comparison and see how the Program works.

BN: If the traffic restrictions are imposed, what do you expect for air quality?

Tang: This is not the first time Beijing has imposed traffic restrictions. During the Sino-African Cooperation Forum, we did well in improving the air quality because we forbade more than 400,000 cars belonging to companies or the government driven on the road.

A survey by Harvard University shows from satellite pictures that the nitrogen oxides were reduced significantly during those days.

This time, we have done a lot of arrangements and preparations, including researching the conditions of meteorology and emissions.

BN: What difficulties will be encountered?

Tang: Rainy days. For example, we had no way to get valid data during the thunderstorms a few days ago.

(China.org.cn by Zheng Na, Lu Lu and Fan Cong, August 13, 2007)