Acoustical indicators and index for urban quality evaluation

In the urban health evaluation, the environmental comfort (thermo-hygrometrical, acoustical and lighting comfort and IAQ) represents a fundamental aspect to quantify the influence of the climate and of the human activities on the men's health. The correlations among outdoor comfort, urban landscape and architectural features offer wide perspectives, as they could represent very useful means to give a qualitative and quantitative judgment on the existing real estate or to choose the major actions for the restoration of the urban environment. To obtain urban health global judgment, all the playing factors must be correctly weighted and associated. An analysis based on homogeneous quantities is needed, avoiding multiplying judgment scales and using, for example, one scale for each involved parameter comparable with the others. To quantify and correlate the various environmental elements, a first attempt was performed aimed at a global assessment on the basis of a mutual judgment system. In this paper a proposal of schematisation based on indicators and index has been developed. With the definition of them, relating to the acoustical outdoor comfort evaluation, it is possible to obtain a global quality environment evaluation considering also other aspects like, for example, thermo-hygrometrical and atmospheric pollution effects. First analyses to validate the method on the basis of experimental and simulated sound pressure levels have been developed. Moreover, noise level data, traffic and population density were considered as basic parameters on which it is possible to develop single indicators and a global acoustic quality index. In the meantime a subjective investigation was performed, to correlate the values of the acoustical index to the individual sensation of the people living in the zones of the investigation.