Aircraft and Background Noise Annoyance Effects

Abstract

Traditionally, community aircraft flyover annoyance has been studied in the absence of other noises. However, the importance of considering the flyovers along with other community noise sources is gaining increasing awareness. To investigate annoyance of multiple noise sources, two experiments were conducted. The first experiment used 48 subjects, and the second used 216 subjects. The first experiment was designed to establish annoyance-noise level functions for three community noise sources presented individually: jet aircraft flyovers, air conditioner, and traffic. This experiment provided baseline data for a second experiment which is currently being conducted to investigate (1) effects of background noise on aircraft annoyance as a function of noise level and spectrum shape; (2) the relative contributions of background noises and aircraft noise to overall annoyance; and (3) effect of type of annoyance rating: overall or source specific. In the second experiment, the subjects were required to make either overall or source specific annoyance ratings or a combination of the two. Both experiments used two dependent measures: rated annoyance and amount of subconscious body movement or fidgeting.

Results of the first experiment indicated that the slope of the annoyance-noise level function for traffic was significantly different from the slopes corresponding to flyover and air conditioner noise. This added further justification to the need to determine the influence of different background noises on aircraft noise annoyance (e.g., experiment two). Preliminary body movement analysis indicated no relationship of body movements to source noise level.

Results of the second experiment showing differential effects of signal-to-noise ratio and background source type across total noise level will be presented and discussed. Results will also be presented to illustrate the effects of all the sources (flyover, air conditiner, and traffic) on relative annoyance as a function of the type of annoyance questionnaire. Further data on the correlation of movement with source noise level will be discussed. However, based on the results of the first experiment, little relation to annoyance is expected. All results will be applied in an effort to develop an improved model of human response to community noise.