Friday, December 10, 2010

Impact of Air Pollution Controls during the 2008 Beijing Olympic Games

This is a summary report by Crop Science Society of America.


China is currently the largest developing country in both area and population in the world. Since the “Economic Reform and Open-Door Policy” of 1978, China’s economy has been developing rapidly. Accompanying this, air pollution has become increasingly serious and is now one of the major environmental concerns in China, especially in large cities. In recent years, the concentration of airborne particulate matter, which is strictly controlled in developed countries, has been very high in many Chinese cities, including Beijing, Shanghai, Guangzhou, and Wuhan.

This has been reported to be one of the causes of the increase in premature mortality and in respiratory and cardiovascular diseases observed in some Chinese cities. Besides health impacts, the concentrations of air pollutants associated with eutrophication and acidification, such as ammonia (NH3), nitrogen (NO2), and sulfur dioxide (SO2) and their corresponding secondary particulates, have also been found to be high in many areas in China.

Although some laws, regulations, and standards have been established to tackle air pollution problems in China, the priority of economic development over environmental protection weakens their enforcement. Therefore, air pollution in China remains very serious.

In August 2008, the Summer Olympic Games were held in Beijing. To fulfill the requirements for air quality during the Games, several measures were enforced to reduce ambient air pollutant concentrations. These measures included the so-called odd-even car ban, stopping production or reducing the output from the most polluting factories, and limiting pollutant emission from coal combustion facilities in Beijing and the surrounding areas.

For example, the odd-even car ban, based on license plate numbers, kept vehicles off the road on alternate days between 20 July and 20 September and suspended the use of 70% of government motor vehicles (nearly 2 million) during that period. As a result of this measure, vehicle emissions of volatile organic compounds (VOCs), carbon monoxide (CO), nitrogen oxides (NOx), and particulate matter (PM) with an aerodynamic diameter of 10 mm or less (PM10) during the Games were estimated to be reduced by 55.5, 56.8, 45.7 and 51.6%, respectively, compared with the emissions before the Olympics. Similar temporary vehicle use controls were found to improve air quality in the 2004 Athens Olympics, the 2002 Busan Asian Games, and the 1996 Atlanta Olympics.

Similar measures limiting pollutant emissions were enforced in neighboring Tianjin, Hebei, Shanxi, and Inner Mongolia provinces during the Beijing Games. This presented an invaluable opportunity for scientists to study the anthropogenic contributions to air pollution in Beijing by comparing air pollutant concentrations before, during, and after the Games.

It also allowed an assessment of the effectiveness of the control measures, as well as the opportunity to provide direction for future air pollution control measures in Beijing and the rest of China.

The objectives of this study were to show the change in concentrations of a range of major atmospheric pollutants (i.e., PM10, PM2.5, inorganic ions in PM, NH3, NO2, SO2) before, during, and after the Olympic Games as affected by pollution control measures at a suburban site in Beijing through in situ measurements; and to provide scientific insight for controlling air pollution in large cities, especially that induced by anthropogenic reactive nitrogen and sulfur emissions.

The researchers and others studies have all showed large decreases of PM10, PM2.5, NH3, NO2, and SO2 concentrations in Beijing during the Olympic period when strict emission control measures were adopted. This suggests that the pollution control measures are effective. Thus lower air pollutant concentrations can be achieved in areas where serious pollution occurs due to anthropogenic emissions if strict measures for controlling pollutant emission can be executed.

Air pollution caused by particulate matter, reactive nitrogen, and sulfur compounds is still serious in many big cites in China. The experience of air pollution control during the Beijing Olympic Games may help in controlling air pollution in the major cities of China in the future.

The air pollution control during the Beijing Olympics mainly focused on reducing emissions from transportation and industry. In view of the importance of NH3 in secondary particle formation and relatively high NH3 concentration in Beijing (a mean of 17 mg m−3 at DBW during 2006–2009), reducing NH3 emission from agricultural sources may also be important for controlling air pollution.

The “blue sky” over Beijing during the Olympic period was achieved, but at the cost of reduced gross domestic product growth rate and inconvenience. After the Games, to reestablish a high rate of economic development, most of the emission controls were removed, and air pollution quickly became serious again, a view strongly supported by the BPNEP data (BPNEP, 2009). The rapid economic development (particularly the rapid growth of private car numbers) is accompanied by high energy consumption, 70% of which is from coal in China. Besides this, energy use efficiency is low and the exhaust gases from energy consumption are not decontaminated effectively before being emitted to the atmosphere.

Also, as the real-estate sector develops rapidly, many construction sites are producing pollutants. In view of the priority given to economic development in China, and the difficulties in controlling air pollution, much greater and lasting efforts will be needed to get “blue-sky days” in its large cities in the future.

Significant decreases in PM10, PM2.5, NO2, SO2, and particulate inorganic ion concentrations were found in Beijing during the 2008 Olympic period, although different reduction rates can be given by researchers due to the discrepancy of the chosen baselines.

These decreases indicate that the pollution control measures were successful. Thus, lower air pollutant concentrations can be achieved in areas where serious pollution occurs due to anthropogenic emissions if strict measures for controlling pollutant emission (including controlling NH3 emission from agriculture) can be executed.

But air pollution quickly became serious again after the Olympic Games; the “blue sky” over Beijing during the Olympic period existed only for a very short period. The short successful pollution controls in Beijing reveal the difficulties in controlling air pollution and the much greater efforts required to get “blue-sky days” in mega-cities of China in the future. It would be worthwhile for China and other rapidly developing regions to reduce emissions of anthropogenic pollutants (i.e., reactive N and sulfur compounds) substantially by efficient resource use or even partly sacrificing their economic growth rates, to obtain a better environment for their people and next generations.

Material adapted from:

Impacts of Pollution Controls on Air Quality in Beijing during the 2008 Olympic Games

Jianlin Shen, Aohan Tang, Xuejun Liu, Jenny Kopsch, Andreas Fangmeier, Keith Goulding, and Fusuo Zhang
doi:10.2134/jeq2010.0360; Published online 7 Dec. 2010 in the Journal of Environmental Quality

More on the efforts on "air pollution in China".

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