Management of soundscape

Evaluation of noise in terms of its effect on the quality of life has been reconsidered in Europe since 1977. This process introduced a concept called "soundscape" first coined by R Murray Schafer.  According to the International Standard Organisation (ISO) soundscape is defined as 'the acoustic environment as perceived or experienced and/or understood, by a person or people, in context'.
It recognises sound as a resource, rather than noise as waste. It suggests exploring all of the sound in an environment.  So, a holistic approach is needed in order to understand and evaluate soundscape. It relies on human perception, physical measurement and physical environment. It also relies on human capital in terms of local expertise of a particular environment's inhabitants.

*The person who exposed to noise, their sensational reality depends on the combination of their socio-cultural background and the psychological dimension with the acoustical setting.*
There is a diversity of opinion about soundscape. In one side we have acoustic environment and on the other side we have perceptual construct. This means soundscape exist through human perception. Our aesthetic taste can shape a landscape and our perceptive taste can shape a soundscape. Professor Berglund from Stockholm University suggests that 'the great challenge is not just to decrease the adverse health effects in noisy areas, but to create good and health promoting soundscapes.'There are three basic sources of sound that comprises the soundscape. First sound generates by organisms are referred as the biophony. Second, sound generates from non-biological natural categories are classified as the geophony, and third sound produced by humans are known as anthropophony.  
Most urban cities in South Asia such as in Dhaka, soundscapes are dominated by a subset of anthropophony or technophony such as noise from vehicle or electro-mechanical noise. This sub-class of noise pollution or disturbance can produce a negative effect on a wide range of organisms. It also affects the behavioural characteristics of a human being.
In the United Kingdom (UK), the National Planning Policy Framework introduced a Local Green Space designation, which allows local communities to identify for special protection green areas of particular importance to them. Designating land as Local Green Space local communities will be able to rule out new development other than in very special circumstances. The designation should only be used where the green area is demonstrably special to a local community and holds a particular local significance, for example because of its beauty, historic significance, recreational value, tranquillity or richness of its wildlife.
One of the expected soundscape parameter is tranquillity, which has been included in the UK noise policy. There are no precise rules, but for an area to be protected for its tranquillity it is likely to be relatively undisturbed by noise from human caused sources.
In addition to the designation of green space, current policy also requires, where possible, the improvement of health and quality of life through effective noise management. Different European Environmental Noise Directives has been introduced to reduce environmental noise level. Also the preservation of natural soundscapes is now a recognized conservation goal in Europe.
Addressing noise issues is more than simply seeking sound level or exposure reduction rather it is also about managing the acoustic environment or soundscape. There are other scientific issues such as the concepts from toxicology apply to noise impacts assessment. These are NOEL -- No Observed Effect Level.
This is the level below which no effect can be detected.  LOAEL -- Lowest Observed Adverse Effect Level. This is the level above which adverse effects on health and quality of life can be detected. SOAEL -- Significant Observed Adverse Effect Level. This is the level above which significant adverse effects on health and quality of life occur.
Recently, some research reported in media suggests that in Bangladesh actual level of noise in silent areas are much higher than acceptable limit of sound. As a result of that due to sound pollution people are suffering from physical, psychological health hazard along with sleep disturbance.  
It is a well known fact that constant exposure to high levels of noise is likely to cause headache, hypertension, insomnia, nervousness, hearing loss, and dementia. Research also suggests that noise induced hearing loss is a common disease in urban areas.
Think about noise in Dhaka city, which is mainly from traffic noise. This is causing annoyance to individual and also a contributing factor for non-visual orientation in one's daily life. On the other hand, certain level of music noise has soothing affect which help dementia patient.
The person who exposed to noise, their sensational reality depends on the combination of their socio-cultural background and the psychological dimension with the acoustical setting. So, the exploration of the soundscape requires both microscopic as well as macroscopic tool.
Cost benefit analysis of noise take account of the cost of noise and the value of quiet areas. In an environmental impact assessment noise assessment should be considered.  First consider the impact of high noise level on amenity. This take into account adverse impact on quality of life, well-being, property
prices etc.
Second consider health. This take account of hearing impairment, mental health, cardiovascular effects, sleep disturbance, cognitive development etc.
Third consideration is productivity. This take account of cognitive effects in children, concentration, creativity, reduced work productivity through tiredness etc.
Fourth consideration is ecosystems. This takes account of effects on factors such as animal health, breeding patterns, communication and foraging.
Almost all existing valuation work looks at costs and dis-benefits of high noise levels, not benefits of low noise levels or benefits of quiet or benefits of good quality acoustic environment/good quality soundscape. Identification and valuation of these benefits may provide evidence to support the protection and enhancement of the acoustic environment.
However, one should be careful about the fact that concentrating efforts towards managing noise hot-spots may result in a spreading of noise into areas and times where levels are currently low.
In his book, Silence in the age of noise Norwegian writer Erling Kagge argued that "Silence in itself is rich. It is exclusive and luxurious and a key to unlock new ways of thinking.
I don't regard it as a renunciation or something spiritual, but rather as a practical resource for living a richer life." In fact silence works with the whole person on many levels. Silence can help us not only to feel better physically and to experience calmness and clarity of mind, but also to have more intuition, creativity and compassion in our daily lives.
So, an atmosphere or environment created by or with sound of appropriate level is important. In order to achieve this, unnecessary horn in city area should stop. Within the urban areas any landscape development should be in compatible with soundscape ecology and in order to achieve this community engagement is needed.

Dr Kanan Purkayastha is an Environmental Advisor and writer based in UK The views are the author's own and do not reflect the view of the organisation he works.