RACHEL PETKEWICH
In London, C is for congestion charge. Drivers must pay a daily fee on weekdays to bring their cars into certain parts of the city.
in fleet composition in London have exceeded expectations, says Sean Beevers, a modeler in the Environmental Research Group at King’s College London. For the past 10 years, Beevers and his colleagues have been taking air measurements and modeling air quality around the city with the London Air Quality Network, a series of monitoring stations. Car and heavy-truck traffic in the area decreased by 30 and 11%, respectively, whereas bus and taxi traffic increased by 20 and 13%, respectively. Average car speeds were improved by 20%. This kind of traffic management gets cars moving in central London, and increased speed really reduces the pollutant emissions per kilometer traveled, the researchers report. As a result, nitrogen oxides and particulate matter less than 2.5 micrometers (measured as an aggregated number over 1.5- or 2-hour time periods) each decreased by 12%, and CO2 levels plummeted by 20%. The researchers believe that the increase in traffic speeds is at least as effective at reducing emissions as fewer cars on the road or improvements in vehicle technology between 2002 and 2003. “Certain people have to drive in London, such as delivery trucks, so let’s create an incentive for them to bring the cleanest vehicle,” says Colin Matthews, head of Transport Energy Programmes at the Energy Saving Trust, a U.K. nonprofit organization. He says people have bought hybrids and other clean cars, heavy trucks, and vans to take advantage of the discount available. Free-flowing traffic also reduced the number of accidents, he adds. Tom Downs, president of the U.S. nonprofit group Eno Transportation, notes that the key to success was to beef up public transport first. “London proved [cities] can’t simply price road access without creating options in advance.” —RACHEL PETKEWICH
News Briefs State of North Korea’s environment The Democratic People’s Republic of Korea faces significant environmental challenges, according to the first assessment of its environment, which was conducted by the United Nations Environment Programme (UNEP) and Korean authorities. When the report was released in late August, UNEP and the Korean government signed a framework agreement to guide joint activities in environmental protection, including projects to improve data collection and monitoring. The report calls for better protection of water resources. Other priorities are air pollution, forest depletion, and biodiversity protection. State of Environment DPR Korea 2003 is at www.rrcap.unep.org/ reports/soe/dprksoe.cfm.
Progress on PM A U.S. EPA report released in September describes the quantitative link between exposure to ambient particulate matter and morbidity and mortality, which is one of the major accomplishments of the Particulate Matter Research Program during the past five years. EPA scientists, university grantees, and other scientists at U.S. research institutions conducted the research summarized in the report, which the agency described as “part of a federally coordinated effort to define particulate matter health effects.” In 1997, EPA revised the National Ambient Air Quality Standards to set a standard for particles less than 2.5 micrometers after these pollutants were linked to cardiovascular problems. In 2004, EPA created additional regulations. Particulate Matter Research Program: Five Years of Progress is available at www.epa.gov/pmresearch.
NOVEMBER 1, 2004 / ENVIRONMENTAL SCIENCE & TECHNOLOGY ■ 409A
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“Congestion charging is a way of ensuring that those using valuable and congested road space make a financial contribution,” according to Transport for London, the city’s transport authority. Certain vehicles are exempt from the charge—including taxis and emergency vehicles. Cameras monitor license plates. The owners of nonexempt vehicles who fail to pay the daily fee can be slapped with hefty fines. All the money collected pays for improvements to the bus and underground rail systems. The program has been generally viewed as a success, and in August, London’s mayor, Ken Livingstone, proposed expanding the congestion-charge area into Kensington, Chelsea, and Westminster. If accepted, charges in the new area would go into effect in 2006. London is not the first city to implement congestion charges. Singapore officials established their system in 1975 and updated it to electronic road pricing in 1998. Other cities have instituted similar charging systems on smaller scales. Traffic reductions and changes
