Emission-reduction effort in London fails to improve air quality

New Scientist : Despite the establishment of a low-emission zone in London in 2008 to try to cut the city’s traffic-related air pollution, no measurable improvement in air quality was achieved during the first three years of the program, according to a study by Frank Kelly of King’s College London and his colleagues. The researchers based their finding on measurements of air particulates and polluting gases, such as nitrogen oxide, and on the respiratory health of schoolchildren. They found neither measurable decreases in NOx or particulate matter nor marked improvement of various pollution-related symptoms, such as wheezing, rhinitis, and eczema, in children at 23 London schools. The researchers say one reason might be an increase in the number of diesel-powered vehicles, which have been promoted as producing fewer greenhouse gases but which may also generate more health-compromising pollutants.