School of Geography - Theses
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ItemUrban road traffic noise and health( 2000)Some people say they are annoyed by traffic noise. There is rather a lot of evidence to show that where traffic noise is louder, more people say they are annoyed by it. On the basis of this sort of evidence, there is a consensus that road traffic noise causes annoyance. Traffic noise is also suspected of being dangerous to health: of making people ill; so ill they reach for painkillers or even visit a doctor to get medicine prescribed. The fundamental aim of this thesis is to find out whether this is happening in Melbourne. The available evidence contains anomalies: people seem to be healthy where noise is loudest. Even annoyance studies sometimes detect unexplained peaks of annoyance in quieter places; or a plateau of annoyance in high noise. However, the anomalies display a certain consistency. Traffic noise is orthodoxly measured by loudness. Several studies have found a peak of annoyance at around 60 decibels. The consistency of the anomalies suggests that some other physical characteristic of noise may be responsible for the anomalous responses. This thesis sets out to explore the urban soundscape in an attempt to find such a characteristic, and discovers the pattern of alternation of passby noise and background sound: passby patterns. The orthodox loudness measure is essentially a proxy for the daily average sound energy delivered to the ear by traffic. To define patterns requires taking this measure apart - splitting traffic noise into two sounds: the sound of passbys and the background sound. The definition builds up through the use of point source theory, observations in urban and rural environments, experiments with a typical sedan in isolated locations, and experimentation with techniques for the measurement of background sound generated by roads. The tools applied are ears, stopwatch and sound meter. The result is a set of techniques aimed to measure patterns of passby noise in urban environments. Application of these techniques at 102 randomly selected sites spread over 150km2 of urban environments detects passby patterns in Melbourne. By way of an example, the final stage of this investigation embeds pattern measurements within a small, orthodox study of the annoyance and health responses to traffic noise measured by decibels. The results are consistent with regular or rapidly alternating passby patterns being closely associated with annoyance and ill health. In particular, in relation to people who are sensitive to noise, it should no longer be assumed that peak distress at approximately 60dB(A) is anomalous. It may well be due to high levels of patterning of passby noise. The result requires confirmation, to be sure, but the evidence is sufficiently strong to suggest that traffic noise and patterns of passby noise, or something closely associated with them, are probably associated with health problems in Melbourne.