Our perception of sound is governed not only by sound pressure levels, as measured in decibels. Numerous other factors exert an influence. The composition of sound (noises from transport, fans, children playing, conversations and so forth) is one example. The term ‘soundscape´ includes every factor that affects how we perceive the acoustic environment. Aspects studied in ‘Soundscape Support to Health´ included the characteristics of positive and negative soundscapes, and how they affect our health and well-being. The potentially detrimental effect of noise from road traffic on our health, for example, is well established.International studies
In studies carried out in Sweden, Germany, the Netherlands and elsewhere, residents of areas severely affected by road-traffic noise have been found to suffer more than others from stress-related illnesses, especially cardiovascular disease. For Sweden´s part, the number of people concerned may be broadly comparable to the number of fatalities in road accidents. In monetary terms, it may be a matter of some tens of billions of kronor a year, according to calculations performed by Truls Gjestvang at the SINTEF Group, a multidisciplinary Norwegian research institution. These figures were presented at a seminar held by the research programme in Gothenburg last year.
Kjell Spång, programme manager of ‘Soundscape Support to Health´, says: ‘These research findings show fairly clearly that we´re paying a high price today, in the form of impaired health, for high levels of traffic noise in our urban areas.´
Good soundscapes
‘We can see,´ Spång continues, ‘that having good soundscapes in our vicinity is a key factor in public health, and benefits the economy as well. At the same time, more and more people are living in built-up areas, without access to good soundscapes. We need to find ways of combining life in urban areas with access to favourable soundscapes. In measurements carried out in the programme, we´ve managed to show that the number of people disturbed by traffic noise is halved if their homes have an attractive, “quiet" side. In terms of the measurable data, a “quiet side" is defined as having no more than 48 decibels, as a 24-hour average, two metres from the façade. To achieve this, proper barriers to noise from adjacent traffic must be set up. What´s more, the quiet side must be a visually relaxing environment with green elements, one that provides scope for social relations — a green courtyard, for example.´
Positive soundscape
What, then, characterises a positive soundscape, and how can its overall quality be measured? Through what are known as ‘listening walks´ in genuine environments and in laboratories where acoustic environments are recreated, the programme has engaged a number of people as subjects to listen to, and gauge their perceptions of, various soundscapes. The researchers have also developed a method of measuring soundscape quality.
‘One general statement one can make is that “technical" sounds, such noise from traffic or a fan, are perceived as disagreeable by virtually everyone. Other, social sounds, such as conversation, are regarded by most people as neutral to positive. And almost everyone finds sounds from children´s games positive,´ Kjell Spång says.
‘It´s vital,´ he adds, ‘to point out that a positive acoustic environment isn´t the same as total silence. On the other hand, technical sounds must be below a certain level in order for positive sounds to be perceived as such at all.´
Throughout the course of the programme, its results have been communicated to various public stakeholders, i.e. local, regional and national agencies and boards. The Swedish National Board of Housing, Building and Planning, for example, has adapted its guidelines in the light of the programme findings.
Noise barriers
One highly practical application of the programme´s results is the noise abatement under way in a housing area in the municipality of Partille, in south-west Sweden. By joining homes and erecting noise barriers, disturbance from traffic noise on the most exposed side of the housing area has been reduced, and a ‘quiet side´ created.
The programme and its results also live on in the knowledge portal that the researchers have established. This portal comprises three levels, from a more general to a more research-oriented level.
‘The portal will be updated with new research findings, and it will be possible to post questions there for the people involved in it to answer. It will also give the research team a reason to meet at least once a year to update the content,´ Kjell Spång relates.
Links
Link to the knowledge portal (in Swedish)
