Evaluation of outdoor environment in preschools using the soundscape approach

Abstract: Exposure to high levels of noise may affect a person’s health and behavior. A lot of education in Swedish preschool occurs outdoor, which makes having good sound environment important for the children and the teachers. Today, Swedish preschools use equivalent sound level Leq24h and max sound level Lmax for outdoor sound environment benchmark values. These standardized sound level indicators have shown some limitations in certain sound conditions such as tonal components, multisource environments, or low frequency noise. During the last couple of years, the soundscape research has seen growth. With information from new research and ISO standards, the soundscape method could prove to be a good complementary to the current standardized approach. This master thesis, among other things, examines how soundscape study can improve the outdoor sound environment in preschools and assesses correlation between measurements and the subjective experience of the participants. Outdoor measurements are conducted in preschools, where educators answer a soundscape questionnaire. The results of the measurements and questionnaires are compiled and analyzed using statistical methods. Psychoacoustic metrics loudness, roughness, sharpness, and fluctuation strength are calculated. In general, no clear correlation is found between questionnaire answers and the parameters. The highest correlation is found between max loudness Nmax and the perception of natural sound. Soundscapes can give more tools to distinguish what type of sound environment more easily is perceived as good or bad, which can be used by not only acousticians but also other professions. With more statistical data better prediction models could be created to predict what type of levels of sharpness, or other indicators, would be necessary to affect how well the sound environment would be perceived. Soundscape method is still however new, especially in terms of standardization and is still being improved upon.