Environmental noise logging and calculating

Abstract

Noise pollution in urban environments is a common problem that affects people's health and quality of life. It is therefore one of the main issues addressed in many studies of environmental noise level assessment. The equivalent sound pressure level (L Aeq ) is one of the most widely used indicators for evaluating environmental noise from roads, railways, and industry. According to the European framework of noise management, the day-evening-night noise indicator L den is calculated on the basis of the L Aeq measurements. Several studies show that the use of only one parameter for noise levels assessments is a simplification and it is necessary to take into account the noise frequency characteristics. So the use of parameters, which can estimate subjective people's feelings, are required. In this paper, we analyze the suitability of using the psychoacoustic metrics given by Zwicker's/ISO532 model, in addition to L Aeq . The calculation of the parameters of this model for annoyance assessment requires considerable signal processing features which wireless sensor nodes do not have. Therefore, we propose a two-stage approach. At the first stage a conventional noise measurement is performed. The noise data is logged and the equivalent noise L Aeq over defined time T (LAeq, T) is computed and forwarded to a database. At the second stage, using the logged data, basic psychoacoustic parameters are computed in a LabVIEW environment. Finally, sensor node prototypes and preliminary test results are presented.