Annoyance

Noise consists of sounds that people do not enjoy and do not want to hear. However, it is difficult to relate the annoyance caused by noise to purely acoustical phenomena or descriptors. When people are forced to listen to noise against their will, they may find it annoying, and certainly if the sound pressure level of the noise increases as they are listening, their annoyance will likely increase. Louder sounds are usually more annoying, but the annoyance caused by a noise is not determined solely by its loudness.

Very short bursts of noise are usually judged to be not as loud as longer bursts at the same sound pressure level. The loudness increases as the burst duration is increased until it reaches about 1/8 to 1/4 seconds, after which the loudness reaches an asymptotic value, and the duration of the noise at that level does not affect its judged loudness. On the other hand, the annoyance of a noise at a constant sound pressure level may continue growing well beyond the 1/4 seconds burst duration as the noise disturbance continues [1].

Annoyance caused by noise also depends on several other factors apart from the acoustical aspects, which include its spectral content, tonal content, cyclic or repetitive nature, frequency of occurrence, and time of day. Nonacoustical factors include biological and sociological factors and such factors as previous experience and perceived malfeasance. We are all aware of the annoyance caused by noise that we cannot easily control, such as that caused by barking dogs, dripping taps, humming of fluorescent lights, and the like. The fact that the listener does not benefit from the noise, cannot stop the noise, and/or control it is important. For instance, the noise made by one’s own automobile may not be judged very annoying while the noise made by other peoples’ vehicles, motorcycles, lawnmowers, and aircraft operations at a nearby airport, even if experienced at lower sound pressure levels, may be judged much more disturbing and annoying.

Of course, noise annoyance is difficult to measure and is possibly subject to biasing effects. Whenever a team of people is introduced into a neighborhood to make a social survey, there is a danger that their mere presence may affect people’s attitudes. The design of the questionnaire and the way in which it is conducted can also seriously affect the results [2]. The response of a community to noise is even more complicated than the response of individuals. It has been found that individuals who are driven to make a complaint are not always those most annoyed. Also, of those seriously disturbed, only a small fraction will complain. With individuals, noise annoyance is complicated by other factors, e.g. whether a man or woman is annoyed by other factors such as marital quarrels. When concerned with community response, additional factors such as social and political circumstances, noise action groups, and community attitudes toward the noise and even the regulatory authorities may be important. Here the public relations activities of the noise maker are clearly important. If the community is convinced that the noise intrusion is necessary for their economic wellbeing or their safety, then their acceptance of the situation is much more likely to occur (see Chapter 16). Chapter 6 reviews the annoyance caused by noise in more detail and provides references for further reading.