Characterization of short duration noise events for the evaluation of annoyance in schools exposed to traffic noise

The relationship between traffic noise and corresponding annoyance has been widely investigated in literature. In particular, the effect of noise on students has been studied, for instance the correlation between road traffic noise perceived in classrooms and the student's performance, including reduced memory, motivation and reading ability. These studies mainly investigated the relationship between the A weighted equivalent sound pressure level LAeq, measured over the teaching period and/or in noise neighborhood, and the cognitive impairment of students and children. Anyway, the annoyance of students and other subjects is frequently related to the effect of short duration noise events characterized by high levels, such as the aircraft fly-over noise, pass-by of buses, heavy trucks, motorcycles or street sweepers. These noise events are often described, over specific measurement periods, in terms of maximum A weighted SPL, LAmax, or statistical levels, such as LA1 or LA10. This aspect is not considered in the noise maps drawn in accordance with the European Environmental Noise Directive, as they provide the LAeq only, determined over day, evening and night periods. The paper analyses the correlation between the equivalent LAeq, determined over 1 hour periods, and the maximum and statistical levels due to traffic noise in different kinds of road. This analysis is carried out on several urban roads belonging to different typologies and characterized by different kind of traffic. The results can be useful for further analysis on the relationship between traffic noise events of short duration and the corresponding annoyance in schools and in other type of buildings.