There is deep concern over air quality in China especially during the 2008 Olympics held there. Concern was raised over the air quality, and its potential effect on the athletes. Beijing committed then to remove 60,000 taxis and buses from the roads by the end of 2007 and relocate 200 local factories, including a prominent steel factory, China’s Olympian attempt to improve air quality during the 2008 summer games did more than provide a healthier atmosphere for the athletes. It also demonstrated that widespread changes in transportation patterns could greatly reduce the threat of climate change. New research by an international team of scientists led by the National Center for Atmospheric Research (NCAR) indicates that China’s restrictions on motor vehicles had the side benefit of dramatically cutting emissions of carbon dioxide by 24,000 to 96,000 metric tons (about 26,500 to 106,000 U.S. tons) during the event.
There is deep concern over air quality in China especially during the 2008 Olympics held there. Concern was raised over the air quality, and its potential effect on the athletes. Beijing committed then to remove 60,000 taxis and buses from the roads by the end of 2007 and relocate 200 local factories, including a prominent steel factory, China’s Olympian attempt to improve air quality during the 2008 summer games did more than provide a healthier atmosphere for the athletes. It also demonstrated that widespread changes in transportation patterns could greatly reduce the threat of climate change. New research by an international team of scientists led by the National Center for Atmospheric Research (NCAR) indicates that China’s restrictions on motor vehicles had the side benefit of dramatically cutting emissions of carbon dioxide by 24,000 to 96,000 metric tons (about 26,500 to 106,000 U.S. tons) during the event.
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To put this in perspective, the authors note that this reduction by a single city represents more than one-quarter of 1 percent of the emissions cut that would be necessary worldwide, on a sustained basis, to prevent the planet from heating up by more than about 2 degrees Celsius (3.6 degrees Fahrenheit) by the end of this century. That is the amount of heating generally considered to lead to major societal impacts.
"The Beijing Olympics allowed us to actually measure what happens when people drive much less, and it turns out that it makes quite a substantial difference to our climate," says NCAR scientist Helen Worden, the lead author. "People may think their choice of how to commute to work doesn’t make a difference, whether driving their cars or riding their bikes. But on a large scale, it really does."
Recent research has confirmed that the restrictions successfully reduced levels of air pollutants such as carbon monoxide and ozone. Worden and her colleagues, using new methods in satellite observations and computer simulations, were also able to estimate the impact on carbon dioxide, a powerful greenhouse gas.
"This implies that sustained controls on urban transportation emissions, on the scale implemented in Beijing, could potentially provide a significant part of [emissions reduction]," the study concludes. "However, in this study, we do not address the sustainability of these controls or the feasibility of applying traffic restrictions in other cities."
The research required several steps. Worden and her colleagues first turned to an instrument developed by NCAR and the University of Toronto called MOPITT (Measurements of Pollution in the Troposphere), which flies aboard NASA’s EOS-Terra Satellite. The instrument’s measurements, analyzed with a new multispectral data product, enabled the researchers to estimate the amount of carbon monoxide in the Beijing atmosphere in August 2007, without traffic restrictions, and in August 2008, during the Olympics.
The researchers then inferred the amount of carbon dioxide emissions by drawing on other studies in Beijing that have measured the ratio of emissions of the two gases at 0.03 grams of carbon monoxide to 1.0 grams of carbon dioxide. They used simulations by the NCAR-based Weather Research and Forecasting model (WRF) to fill in gaps in the observations because MOPITT could not obtain measurements during overcast days. The computer model also enabled the researchers to focus on carbon dioxide emissions from motor vehicles as opposed to other sources, such as factories.
"We knew there had to be some reduction in carbon dioxide from the Beijing traffic restrictions, and this experiment enabled us to find out how much," Worden says.
Beijing air quality improvement required significant changes. Among them were various last ditch measures. In July 2008, stricter emergency pollution controls were introduced, including suspending production at more factories and coal-fired power plants, lowering the number of cars on the road and expanding driving restrictions to nearby Tianjin. In early July, Beijing ordered 40 factories in Tianjin and 300 factories in Tangshan to begin suspending operations in an effort to reduce air pollution. There were license plate restrictions which allowed Beijing motorists to drive on alternate days only.
For further information see Beijing Olympics.
Percent Decrease image via UCAR.
