At present, there is no formal method for predicting and monitoring noise from industrial sources. However, the issue is assuming growing importance, driven by a 2002 Directive on environmental noise which requires Member States to prepare noise maps and action plans (ENDS Report 327, pp 50-51 ).
DEFRA commissioned Bureau Veritas Acoustic Technology to explore the potential for a simple, reproducible and robust method for characterising noise levels from industrial complexes.
The consultants also sent a questionnaire to all 368 English local authorities asking them to identify the three main industrial noise sources in their area and, where available, information on the level and type of noise they emit.
Responses were received from 168 authorities - a 45% response rate. Just 43 said they had no major industrial noise sources in their area. Respondents identified some 300 sites which they considered to be affecting their areas, of which 147 were seen as significant sources of noise. Roughly half of the councils said they already hold noise data for industrial sites.
The data are not sufficiently robust to give a detailed sectoral breakdown. The most common sources of industrial noise were the production and processing of metals and the food industry. However, a broad spread of other sectors was identified, including chemical plants, power stations, car manufacturing, minerals extraction and processing, wood mills, waste transfer stations, ports, printworks and general manufacturing.
The consultants propose a methodology to allow the mapping of industrial noise for "strategic purposes" - although they warn that more detailed measurements "will almost always be necessary to investigate a particular noise issue."
The comments reflect the concerns of the Environment Agency, which is charged with controlling noise from larger sites under the integrated pollution prevention and control (IPPC) Directive.
The Agency is concerned that a methodology which homes in on a single measurement may fail to account for the low frequency, tonal or impulsive nature of many industrial noise sources which can make them annoying even at apparently low levels. The Agency generally requires IPPC applicants to carry out measurements and a full noise assessment rather than relying on acoustic modelling, and is concerned that moving to a simplified methodology could undermine this (ENDS Report 321, p 43 ).
DEFRA is now refining the proposed method and preparing procedural documents, in part to meet the Agency's concerns. It plans to carry out further trials of the approach and seek peer group approval.