Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Chinese traffic restrictions yield quick air cleansing

30.04.2007
Chinese government restrictions on motorists during a three- day conference last fall cut Beijing's emissions of an important class of atmospheric pollutants by up to 40 percent, recent satellite observations indicate. The November restrictions are widely viewed as a dress rehearsal for efforts by the city to slash smog and airborne contaminants when China hosts the 2008 Summer Olympic Games.

The restrictions on Beijing drivers coincided with a summit meeting on China- Africa cooperation from Nov. 4-6, 2006, during which an estimated 800,000 of Beijing's 2.82 million vehicles were taken off the road. Researchers now have used measurements taken from space to evaluate Beijing's air quality before, during and after the conference.

"Traffic restrictions implemented during the Sino-African Summit were remarkably successful in reducing emissions of NOx," report Yuxuan Wang of Harvard University and her colleagues. NOx is a class of nitrogen oxides formed during combustion and thought to contribute to global warming. The research team assessed Beijing's emissions using data from the Dutch-Finnish Ozone Monitoring Instrument aboard NASA's Aura satellite, which was launched in 2004.

"We expected a drop in nitrogen emissions, but not to this extent, and after only a short period of time," Wang adds. She conducted the study with colleagues at Harvard and at the Royal Netherlands Meteorological Institute in De Bilt, Netherlands.

The scientists presented their findings April 28 in Geophysical Research Letters, a journal of the American Geophysical Union.

Past satellite studies by other researchers have detected a "weekend effect"-- reduced NOx emissions on weekends compared to weekdays--over cities and industrial areas in the Europe, Japan, and the U.S.

China is the world's second largest producer of greenhouse gases behind the United States and a major source of atmospheric NOx. Last November's driving restrictions in Beijing ranged from regulating access to specific roads to restricting use of both private and government vehicles.

The size of the resulting NOx reduction surprised Wang and her colleagues in part because it departs from recent estimates. Those say that during non-heating seasons, nearly 70 percent of NOx emissions in the Beijing area are from vehicular emissions. Using this as a standard, the team calculated that there would need to be a 50 percent cut in vehicular use in Beijing to account for the observed 40 percent drop in NOx. This stands in contrast to the reported traffic decrease of nearly 30 percent.

"We're not sure what this means, and there will definitely need to be more detailed data on vehicle energy usage, like gasoline sales data, to develop a more precise value," Wang says.

Traffic cutbacks expected this summer as practice for the Olympics, as well as restrictions during the games themselves, will offer opportunities for further study of the processes determining the quality of air over Beijing, she adds.

The research was supported by the National Science Foundation.

Peter Weiss | AGU
Further information:
http://www.agu.org

More articles from Ecology, The Environment and Conservation:

nachricht Bioinvasion on the rise
15.02.2017 | Universität Konstanz

nachricht Litter Levels in the Depths of the Arctic are On the Rise
10.02.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Tune your radio: galaxies sing while forming stars

21.02.2017 | Physics and Astronomy

Improved Speech Intelligibility and Automatic Speech-to-Text Conversion for Call Centers

21.02.2017 | Trade Fair News

36 big data research projects

21.02.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>