7 Quiet Areas
7.1 Introduction to Quiet Areas and Criteria for Their Designation
The regulations require that Quiet Areas within agglomerations are identified. What does quiet mean? The Transport Research Laboratories ( TRL) undertook research for Defra ( http://www.defra.gov.uk/environment/noise/research/pdf/quiet-areas.pdf) on the subject of Quiet Areas. The research reported that defining, identifying and appreciating the benefits of preserving quiet or relatively Quiet Areas in urban conurbations cuts across many different fields including health, physical and psycho-acoustics, and environmental psychology. An important aspect of the research carried out into Quiet Areas has been to establish the positive effect natural sounds have on health and well-being.
7.2 Current Research Into Quiet Areas
Research carried out in Sweden (Berglund et al., 2004) 1 has examined how adverse health effects of noise are related to individual exposure and perceived soundscapes in residential areas with and without access to Quiet Areas. Their results show that access to a quiet façade of a dwelling reduces annoyance to noise by 10-20%, depending on the sound level from road traffic at the most exposed side. Results suggest (Nilsson and Berglund, 2006) 2 that a good urban outdoor soundscape should (a) be dominated by positive sounds from nature, and (b) have an overall equivalent sound level below 50dB (A) during the daytime.
Research carried out in Norway has examined the relationship between localised areas of noise and quiet within a neighbourhood on residential noise annoyance in Oslo (Klaeboe, 2005) 3. Results indicate that noisy neighbourhoods have the potential to increase residential noise annoyance primarily for apartments exposed to low residential noise levels whereas quiet neighbourhood areas have the potential to reduce residential noise annoyance the most at intermediate and high residential noise levels.
In the Netherlands, reviews of current research has concluded that the percentage of time during which a disturbance is present (or the length of time during which a 'level of quiet' is regarded as acceptable) is generally more important than the actual noise level (van den Berg and van den Berg,2006) 4. Alongside these acoustic criteria additional criteria about the sounds heard which convey positive or negative feelings, with regard to appropriateness for a given context, are also important.
Research carried out in Italy to identify indicators to describe perceived soundscapes is following a similar approach to that found in the Netherlands in that it is related to temporal variations in noise although the method is more complex (Licitra and Memoli, 2006) 5.
Research in the UK into Quiet Areas has primarily been carried out to assist in the implementation of END (Symonds Group Ltd, 2003) 6.
The TRL research recommended that public and open spaces in the UK, should fall within the noise band < 55 dB L day, as determined from the first round of noise mapping) and a minimum area (the candidate area must be at least 9 hectares). The specifications for the filter definitions and the candidate list of Quiet Areas should be reviewed and, where necessary, revised by the relevant authorities before the list is finalised.
The following filter specifications which may require revising include:
- Noise Level filter: The specification of a 55 dB L day limit is seen as an appropriate compromise, based on the mapping requirements of the END and definitions for Quiet Areas used elsewhere in Europe;
- Minimum Area filter: The specification of a minimum area of 9 hectares is based upon consideration of both the minimum area that should lie within the defined noise limit to warrant preservation (50%) and the minimum area required to achieve 55 dB L day, based on the presence of at least one major road at the boundary.
- Minimum Area 'of Quiet' filter: The specification that a minimum area of 4.5 hectares must fall within the noise band < 55 dB L day is to allow areas significantly larger than 9 hectares to qualify as candidate Quiet Areas when less than 50% of the area falls within the specified noise band.