Different types of criteria for dealing with anomalous noise events in urban environments under stable road traffic flow conditions

Abstract

The management of anomalous noise events in the assessment of environmental noise of specific sources is an important issue for determining the actual exposure of the population to noise pollution. Of all the sources currently considered in the European Noise Directive, road traffic is the most important in cities, both in terms of its temporal and spatial presence, as it is generally maintained 24 h a day and affects almost all streets in urban environments. This paper proposes two types of criteria for dealing with these events in urban environments under stable vehicle flow conditions. The results show the convenience of using each type of the suggested criteria for the elimination of anomalous noise events depending on the objective of the research. Those exclusion criteria based on applying a threshold to the average sound level, may be considered the best among the proposed options to study the variation of the annual average LAeq,1h. However, to study the relation between road traffic noise and temperature, a novel proposal for anomalous event elimination criteria based on dividing the full temperature range into small intervals may be a relevant approach. Overall increases of 8 %, respectively, 14 %, in the explanation of variability were found for the criteria C6 (successive application of the thresholds ±10 dB, ±6 dB and ±3 dB at each temperature interval of 3 °C) with respect to the cases where anomalous sound events were not excluded, respectively, using criteria C1 from the scientific literature. The application of this type of criteria for the management of anomalous noise events could also be useful for the study of the relation between road traffic noise and other objective and subjective variables in cities, especially in those areas with a greater daily thermal oscillation.