Cluster Analysis for Temporal Stratification of the Week Days

Noise maps has become the main tool to evaluate the exposure of population to noise pollution. According to the European Noise Directive 2002/49/EC, for noise assessment, at least and should be presented for the minimum time of one year. When the noise assessment is performed by on site measurements, the land use plays an important role as the measurements could be affected by other noise sources, examples of them could be night clubs, sport centers, hospitals, shopping malls and so on. In order to improve the long term estimation for the night period, a cluster analysis using the equivalent level of each day of the year of 14 different sampling points was performed to find out the influence of leisure noise in the temporal stratification of noise levels related to the land use. It is shown that the week days stratas are changed by the influence of leisure activities. Modifying the stratas to the ones found by the cluster analysis yields into a long term estimation with a reduced temporal sampling compared to sampling randomly during the year.