Practical ranges of loudness levels of various types of environmental noise, including traffic noise, aircraft noise, and industrial noise

In environmental noise control one commonly employs the A-weighted sound level as an approximate measure of the effect of noise on people. A measure that is more closely related to direct human perception of noise is the loudness level. At constant A-weighted sound level, the loudness level of a noise signal varies considerably with the shape of the frequency spectrum of the noise signal. In particular the bandwidth of the spectrum has a large effect on the loudness level, due to the effect of critical bands in the human hearing system. The low-frequency content of the spectrum also has an effect on the loudness level. In this note the relation between loudness level and A-weighted sound level is analyzed for various environmental noise spectra, including spectra of traffic noise, aircraft noise, and industrial noise. From loudness levels calculated for these environmental noise spectra, diagrams are constructed that show the relation between loudness level, A-weighted sound level, and shape of the spectrum. The diagrams show that the upper limits of the loudness level for broadband environmental noise spectra are about 20 to 40 phon higher than the lower limits for narrowband spectra, which correspond to the loudness levels of pure tones. The diagrams are useful for assessing limitations and potential improvements of environmental noise control methods and policy based on A-weighted sound levels.     

Conclusions from traffic noise studies: suggestions for noise thresholds

Summary Based on 4 surveys, threshold limit values for noise are proposed; beside noise immissions, the quality of living has also been considered.Practical alternatives for noise protection are discussed.

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Résumé 4 études ont permis de proposer des valeurs limites de bruit; outre les immissions de bruit, la qualité de l'habitat a été prise en considération.Des alternatives sont discutées quant aux mesures pratiques pour la protection contre le bruit.

     

Aircraft noise annoyance and average versus maximum noise levels.

A questionnaire study was performed in seven areas located around the airports of Landvetter and Save, Gothenburg, in an attempt to elucidate the extent of annoyance in populations exposed to aircraft noise. Noise exposure was estimated as the energy equivalent level (Aircraft Noise Level--FBN) or as the number of aircraft with levels that exceeded 70 dBA, combined with the maximum noise level. The results were compared with data obtained from the earlier Scandinavian Aircraft Noise Investigation. The results supported the conclusion that the annoyance reaction is better related to the number of aircraft and the maximum noise level than to energy equivalent levels for noise exposure.     

Interpreting noise dosimeter results based on different noise standards.

Three types of noise dosimeters were exposed on workers during routine work in a synthetic rubber plant, two refineries, a petrochemical plant, a petroleum marketing terminal and an off-shore producing platform. The dosimeters represent different methods of noise integration.     

The concept of noise sensitivity: implications for noise control

The term "noise sensitivity" is frequently used in many areas of noise research. However, it can be used to describe several different effects and it can be measured in different ways. In noise surveys, noise sensitivity refers to the fact that individuals differ in the annoyance produced by different sources of noise. Noise sensitivity can be viewed as an independent variable, which may be directly related to outcomes such as health status, or it can be conceptualized as a factor that modifies or mediates the effects of noise exposure on the outcome measure. Noise sensitivity is highly correlated with the general trait negative affectivity, a measure of the extent to which individuals perceive or report negative features of their environment or self. Indeed, few studies have demonstrated effects of noise sensitivity that are independent of negative affectivity. This implies that it is most appropriate to examine general indicators of reported sensitivity rather than a noise-specific measure. Noise sensitivity can also be considered in terms of physiological reactivity to noise sources. Such effects are often only weakly associated with self-reports of noise sensitivity. Habituation to noise is also an important topic to consider and again this appears to be largely independent of self-reported noise sensitivity. Overall, it would appear that it is important to distinguish between subjective reports of noise sensitivity and objective indicators. Different factors will modify these two aspects of noise sensitivity and this implies that different strategies are needed to influence them. Such effects must be taken into consideration when one considers whether control should be targeted at the community in general, or whether it should also cover the most sensitive individuals.     

Environmental noise nuisance

Summary Severe noise problems involving a small number of people can often be solved following a detailed examination of the factors involved. At very least, provided the necessary resources are available, the noise source and the offended people can usually be separated by distance or by sound insulation. More usually, however, real noise nuisance problems are very complex, involving trade-offs between the benefits of less noise and the costs of lessening it. It is clearly desirable to minimise the harmful effects of noise upon public health but how low must the limits be set and can the costs be met?In general the environmental planner is faced with two problems, firstly to predict the extent and severity of environmental noise impact and secondly to assess the acceptability, or otherwise, of this impact in some absolute sense. The second of these problems is perhaps the more difficult as its solution ultimately rests on the political question of how many affected people can be justified. But the first is of no less importance since the policy-maker must be able to make qualitative evaluations of the effects of different policy options.This paper examines the problem of environmental noise nuisance what it is and how it can be measured and predicted. Detailed methodology is beyond the scope of the paper which concentrates instead upon a discussion of the factors involved and the nature of the relationships between them.

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Belästigung durch Umgebungslärm

Zusammenfassung Ernsthafte Lärmprobleme, die eine kleine Gruppe von Personen betreffen, können oft durch eine detaillierte Studie der fraglichen Faktoren gelöst werden. Im allgemeinen können die betroffenen Personen wenigstens durch eine entsprechende Distanz oder Geräuschisolation von der Lärmquelle getrennt werden. Die schädlichen Auswirkungen des Lärms auf die Volksgesundheit müssen auf ein Minimum reduziert werden, aber sind die Kosten tragbar?Im allgemeinen sieht sich der Umgebungsplaner zwei Problemen gegenüber, erstens das Ausmass des Umgebungslärms vorauszusagen und zweitens sein erträgliches Maximum festzusetzen. Das zweite dieser Probleme ist wahrscheinlich das schwierigere, da seine Lösung auf der politischen Frage beruht, welche Anzahl betroffener Personen gerechtfertigt ist. Aber auch das erste Problem ist sehr wichtig, da qualitative Schätzungen der Wirkungen verschiedener Verfahrensmöglichkeiten gemacht werden müssen.Dieser Artikel prüft das Problem der Belästigung durch Umgebungslärm, aus was er besteht und wie er gemessen und vorausgesagt werden kann. Der Artikel will keine detaillierte Methodologie aufstellen, sondern sich auf die damit zusammenhängenden Faktoren konzentrieren sowie auf ihre Beziehungen zueinander.

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Bruit ambiant excessif

Résumé De sérieux problèmes de bruit concernant un petit groupe de personnes peuvent souvent être résolus à base d'un examen détaillé des facteurs y relatifs. Au moins, pourvu que les ressources nécessaires soient obtenables, la source du bruit et les personnes affectées par ce bruit peuvent être séparées soit par une distance adéquate soit par des mesures d'isolation sonore. Il est certainement désirable de diminuer les effets nuisibles sur la santé de l'homme, mais où fixer les limites minimum et est-ce que les frais ne surpassent pas les moyens?En général, deux problèmes doivent être résolus: prédire le volume et la sévérité du bruit ambiant et déterminer son maximum acceptable. Le second de ces problèmes est peut-être le plus difficile, en vue du fait que sa solution dépend de la question politique: quel est le nombre justifiable de personnes affectées? Mais le premier n'est pas moins important, puisque des évaluations qualitatives concernant les effets des différents procédés possibles doivent être faites.Cet article examine le problème du bruit ambiant excessif, ce qu'il est et comment il peut être mesuré et prédit. Une méthodologie détaillée n'est pas l'intention de cet article, qui veut uniquement se concentrer sur la discussion des facteurs y relatifs et la nature de leur relations.

     

Industrial noise control

Only option E reduced the overall A-weighted level to less than 90 dBA, and in fact, it reduced it to less than 85 dBA, the level at which OSHA requires a hearing conservation program. Thus, a worker could be exposed to the resulting sound level using option E for up to eight hours. The results of all of the other measures required limited exposure, according to Table 1. Untreated (and without hearing protection), the worker could be exposed to the 112-dBA sound level for only about 15 minutes during the day. Option B would allow the employee to be exposed to the 105-dBA sound level for one hour; Option C of 98 dBA for about 2 hours; and Option D of 91 dBA for about 7 hours. These times assume the worker is not exposed to other high noise levels; otherwise, these have to be accounted for, as well. The best solution depends on how long the parts tumbler is in operation and whether barriers or enclosures are practical. Other solutions may exist, as well. It's always best to have a qualified acoustician evaluate the problem and make recommendations.