54 Assessing the impact of noise can be complex, not least because of the subjective nature of many of its effects. Despite this, a number of approaches to quantifying the impact of changes in noise according to the source, the scale and nature of the proposals have been developed. For example, the impact of new transport infrastructure or industrial developments can be quantified according to the number of people/households affected by an increase or decrease of noise levels measured in average decibels (dB(A)). This approach can also be used to assess the impact of changes to traffic control measures.
55 This is a rapidly developing area and studies are being taken forward to obtain monetary values for noise.31 Recent studies across Europe have yielded a range of values, many of which lie in the range of €20 - 30 per household per decibel per year. The median value from those studies is €23.5 per household per decibel per year (2001 prices).32
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31 The results of DfT noise studies in the UK and guidance on how to implement values when undertaking appraisal are published on the DfT and Defra websites.
32 Summarised in the 2002 report to the European Commission DG Environment "The State of the Art on Economic Valuation of noise" by Stale Navrud .