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Battling against noise pollution for a quieter Europe

May 13, 2005

The first comprehensive methodology to measure and map noise patterns will help the European Union lay down a common approach to avoiding, preventing and reducing harmful noise that currently affects a quarter of Europe's population.

This new technique to calculate and predict noise propagation from different sources was developed and successfully validated by the IST programme-funded project HARMONOISE that ended in January 2005. Its work is being continued in the IMAGINE project under the European Commission's Scientific Support to Policies initiative, with the methodology likely to be adopted across the European Union as the standard for drawing up noise maps that will allow regulators to take effective action.

"HARMONOISE is contributing to the policy goals of the EU in the fight against noise pollution by developing a harmonised and innovative approach to predicting environmental noise levels," explains Margreet Beuving, a senior researcher on the project at AEA Technology Rail in The Netherlands.

Reaching consensus
Under the Directive on the Assessment and Management of Environmental Noise that was approved in 2002, all EU Member States will have to produce strategic noise maps every five years detailing noise pollution from major roads, railways, airports and industrial sites near urban areas. For the first maps due in 2007 national and regional authorities will be able to use their own methods to calculate noise propagation, but by 2012 they will have to use a harmonised method to permit accurate comparisons to draw up more effective noise reduction policies at European, national and regional levels.

HARMONOISE and the follow-up IMAGINE project are contributing to that standard.

"At present every state has its own calculation methods; noise maps made in Germany cannot be compared to those in Holland, for example, because different methods are used to measure propagation and noise sources," Beuving notes. "For the Directive to be applied a standardised method is needed because if you can't compare results from different countries you can't draw up an EU-wide noise pollution map and can't effectively develop an EU-wide policy to specify what action needs to be taken."

Unlike traditional noise prediction methods that depend on linking the propagation of noise to its source and having different models for the propagation depending on the type of source, the HARMONOISE approach can be used to measure noise propagation independently from the source, as it uses one generic propagation model for all different types of noise. The results are expressed in new European noise level indicators, known as Lden and Lnight, that describe environmental noise during the day and night respectively.

HARMONOISE's approach consisted of describing the noise generation and propagation as accurately as possible and then derive a flexible calculation method, that can be used both for noise assessment and for noise mapping. The method may take into account weather patterns in a particular area, permitting predictions about how far sound will travel in colder night air or warmer daytime air or even at different times of year. It can be used for either highly accurate predictions - to within two decibels - or for broader estimates over a large area, thereby creating a generic noise propagation model.

Helping policymakers decide
"There are many advantages to being able to use the same propagation model for different sources, although the principal benefit is that it allows you to describe the source separately, calculate how the sound spreads and predict what source mitigation actions will have what effects," Beuving says. "In doing so it allows policymakers to carry out cost-benefit analyses to determine the best course of action."

Changing the surface on a stretch of road, for example, could either increase or decrease tyre noise depending on the circumstances, while fitting freight trains with composite brake blocks instead of cast-iron ones will cut rolling noise.

"Traditionally noise has been dealt with by building sound barriers but they are costly and not very attractive, so now the focus is turning toward tackling the noise at source," Beuving explains.

While HARMONOISE tested the calculation methodology that predicts the sound levels emanating from sources of road and rail noises in validation trials based on French, German and Italian data, the IMAGINE project will do the same in areas located near industrial sites and airports. It is also taking a more practical approach, developing guidelines for data collection aimed at allowing European Member States to easily implement the methods.

According to Beuving, the European Commission received HARMONOISE's results "very positively" and is likely to adopt the methodology as the standard for noise mapping. From then on the more than one hundred million people across Europe who suffer from noise pollution can expect to lead quieter lives, reducing the annual cost to the EU (estimated at between EUR13 and EUR38 billion) from lost productivity, accidents and health problems caused by lack of sleep and concentration.

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