For city dwellers, maps of noise pollution are a good example of what science can do to improve quality of life.
A three-dimensional (3D) computer graphic can be worth a thousand words. The European Union's efforts to create 3D noise maps of its cities, railways and airports (see page 480) have given experts the tools both to assess the noise pollution to which its citizens are exposed, and to simulate how it can be muffled by intelligent planning of buildings, acoustic shields and speed limits. And less sophisticated versions of the maps have been made available to the public, bringing science closer to the people.
The maps are stunning, with average noise levels superimposed on 3D visualizations of entire cities in coloured contours ranging from pale-green — less than 45 decibels — to deep blue for greater than 79 decibels. They are a powerful way for politicians and the public to better understand noise, and to participate more meaningfully in urban-development and noise-action schemes that were previously limited to experts. Parisians, for example, can now go to the web to look up the noise levels in their street, or even on the façade of their apartment. Where anecdotal evidence and parochial complaints once reigned, the public can now both better argue its own particular gripes and be convinced at a glance of the broader benefits of unpopular controls, such as stricter traffic speed limits.
There is good reason to make a din. Some 80 million Europeans already suffer noise above 65 decibels, enough to cause lost sleep, stress, high blood pressure and even heart attacks, and a further 170 million endure levels that are simply annoying. And traffic of all kinds — the principal source of noise pollution — is set to increase.
Noise modelling is not rocket science, but more research is needed to improve the quality of the geographical information systems and noise data used and to refine the maths and physics of the models. Materials science could bring us quieter road surfaces and more effective acoustic shields, and engineering and fuel science could give us quieter engines. The effect of noise on people and their health also needs to be better understood. The European Union should be congratulated for setting about drafting such a research agenda; other countries should sit up and listen.
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