Measuring and mapping for better noise action plans
The production of strategic noise maps, as required by the EU Environmental Noise Directive (END) (Directive 2002/49/EC), must include noise from any major source such as industrial activities, airports, railways and major roads. The Harmonoise project aimed to improve assessment and management methods for the latter two, and on this basis, the 'Improved methods for the assessment of the generic impact of noise in the environment' (Imagine) project was established for aircraft and industrial noise. The developed noise source databases aim at easy implementation of the methods in all Member States, with noise action plans being based on strategic noise maps. Using the Harmonoise methodology for development of prediction methods for aircraft and industrial noise sources required setting up modified industry and aircraft source models. For both projects, this led to a common assessment method that could eventually be adopted for strategic mapping as defined by the END. Imagine extended the Harmonoise propagation method for practical use and developed a step-by-step method for defining the occurrence of meteorological conditions necessary for weighting short-term levels, on which basis long-term averaged noise levels can then be calculated and determined. The report 'Guidelines for the use of traffic models in noise mapping and noise action planning' allows for the production of more accurate traffic flow data when using a traffic model, and therefore can help authorities and consultants for both noise mapping and noise action planning. Separate guidelines are given for the two. The improved rail model includes combined roughness of wheels and rails as a key parameter for rolling noise, offering a major improvement in modelling accuracy. Improvements to the model and apportionment of noise sub-sources also resulted in a valuable tool for action planning since the effects of noise mitigation can be applied. For industry, general knowledge of the source is not enough; they need to be able to measure the source, given that operations differ greatly among companies. Project efforts resulted in being able to offer a large number of measurement possibilities for obtaining sound power levels of areas and machines, with the source database SourcedB providing a wide range of noise sources based on measurements or formulae. Imagine's aircraft noise model is a source propagation model offering much more accurate analysis; it takes into account factors previously not included such as contributions from sound sources like the engine, fan, jet and aerodynamic effects. The measurement and calculation methods developed by Imagine are harmonised for road, rail, aircraft and industry noise, thus extending available methods considerably. Project advances pave the way for less noise and for better future actions for safeguarding the exposure to noise for certain populations.
