EU project uses plants to muffle urban noise
08 April 2013
Dense planting and other soft materials is better at shielding residents from traffic noise than the straight-sided sound barriers commonly used to prevent noise pollution, according to the results of a EU-funded study.
Apart from being a nuisance, the World Health Organization has stated that noise pollution is associated with health risks such as stress and cardiovascular problems. It has been estimated that the cost of traffic noise in Europe equates to 0.04% of total economic output, mainly from road transport.
The EU-funded HOSANNA project was tasked with tackling the issue of urban noise. Research into noise reduction has, until now, mainly focused on insulation and blocking out the noise. HOSANNA, in contrast, has changed focus to examine how we might quieten the urban environment itself.
The 13 project partners involved in HOSANNA, which ran for three years until November 2012, are supported by a €3.9 million EU grant. The project’s wide-ranging proposals have already attracted interest from decision-makers such as architects, city planners, acoustic consultants and noise-control engineers.
One success story supported by HOSANNA was in Lyon, France, where researchers showed that a natural plant sound shield could deliver significant noise reduction. The project involved setting up a barrier just 15m long, 1m high and 40cm thick in front of the Church of St George on Lyon’s busy Quai Fulchiron.
The wall was made of recycled materials – including coconut fibres and lava stones – and some 1,200 different plants. “Although it is low in height, it is able to muffle sounds,” said Bruno Vincent, a director of Acoucité, a Lyon-based urban noise observatory that worked with HOSANNA on the project. The acoustic performance of the barrier was measured before and after the barrier was erected, with pedestrians asked to assess the sound environment. “The prototype was able to stop sound waves and create a quiet acoustic zone: the noise reduction behind the wall was estimated at between four and eight decibels,” he added.
Vincent, who has worked on noise issues for 25 years and has a PhD in environmental psychoacoustics, said the barrier was also successful in raising interest with politicians and city engineers. “It showed how vegetation could be used to deal with noise,” he said. A key to the success is that it reduced noise and also raised the attractiveness of the location. “It addressed a real problem with a solution that is both practical and visually pleasing: it could be both acoustically efficient and aesthetically attractive. So it is good for us, and it is good for our quality of life.”
The HOSANNA project provided a toolbox to reduce noise pollution that differs from traditional solutions such as sound barriers and speed limits.
“Urban noise can be tackled in two ways. If we can do something with the source of the noise first, we will. After that, we look at the way sound is propagated and perceived,” said Jens Forssén of Gothenburg’s Chalmers University of Technology and the project co-ordinator of HOSANNA.
“We looked at a range of solutions that can help with urban noise reduction. For example, sound barriers that exploit soft materials, vegetation or possibly recycled materials could achieve significant reduction in noise compared to the straight-sided sound barriers commonly used now,” Forssén continued.
“The perception of the sound scope overall is very important, which is why we applied a range of assessments, including questionnaires and even physiological measurements of stress, to assess the effectiveness of the measures we will finally recommend,”
The European Commission unveiled plans in December 2011 to cut vehicle noise in the coming years. The 2002 EU Environmental Noise Directive had already placed heavy obligations on city authorities to solve the problem. To support them, the Commission has invested millions of euro in research projects to find new ways of reducing urban noise.http://www.engineersjournal.ie/2013/04/08/eu-project-uses-plants-to-muffle-urban-noise/http://www.engineersjournal.ie/wp-content/uploads/2013/04/Sound-barrier-1024x682.jpghttp://www.engineersjournal.ie/wp-content/uploads/2013/04/Sound-barrier-300x300.jpgNewsEuropean Union