The EC has published a Green Paper on noise policy in the EU and has issued a directive on the assessment and reduction of environmental noise. This directive will make noise mapping mandatory for cities with at least 250.000 inhabitants. Due to the development in computer technology it is possible to calculate noise maps for large urban areas using the available data on buildings, ground profile, road and rail traffic. Examples for noise mapping are Birmingham (GB), Linz (A) and various German cities. Based on noise maps and empirical data on the correlation between annoyance and noise levels annoyance maps for different sources (rail, road, aircraft) can be calculated . Under the assumption that the annoyance for the different sources are only weakly correlated, a combined annoyance map can be calculated. In a second step using the distribution of the population the actual number of annoyed people can be evaluated. This analysis can be used, for example, to identify noise hot spots and to assess the impact of major traffic projects - roads, airports- on the noise situation as well as the impact on the population. Furthermore, the combined annoyance maps can be used to investigate on health effects and to check whether or not empirical correlations between annoyance and noise levels are sufficiently correct.
Keywords: Noise mapping, annoyance, noise policy, environmental noise
|How to cite this article:|
Knauss D. Noise mapping and annoyance. Noise Health 2002;4:7-11
| Introduction|| |
During the past mobility of people and goods have increased an thus the mount of traffic combined with the increase of environmental noise levels. Beside the annoying effect, noise also influences the public health. To reduce noise levels and to minimize noise polluted areas noise maps are an excellent tool. Noise maps can be used
- For planning purposes
- For setting up noise reduction measures
- For monitoring trends in environmental noise
- To assess the costs of noise reduction measures
Noise maps showing the ambient noise levels can also be used as a basis for further analyses of annoyance effects, e.g. calculating the number of people annoyed by different noise sources. This is an important aspect of noise mapping, since it allows one to easily identify noise 'hot spots' regarding the number of people affected and to minimize the number of people annoyed by noise.
The production of noise maps can be roughly divided into the following steps:
- Collecting traffic data (road, rail, aircraft), data for industry
- Digital model: buildings, screens, topography
- Calculation of noise levels using noise propagation models
- Analysis of the maps (annoyance, planning areas, etc.)
Since in most cases traffic noise is the major noise source in the following we will only consider these noise sources.
One major aspect in noise mapping are the noise limits for the different noise sources which are usually at set at different values. In order to compare the noise limits, a common basis is needed which could be provided by empirical studies on the relation between noise levels and for example annoyance. On the other hand noise maps can also be used to evaluate empirical studies on noise effects on health.
| Noise Maps; Annoyance Maps|| |
The calculation of noise maps are based on traffic data (no. of vehicles, speed, etc.) and a model for calculating the noise levels in the surrounding using these data (Calculation of Road Traffic Noise, Department of Transport (1995); Guide du Bruit des Transports Terrestres Prevision des niveaux sonores (1980); ISO 96132 (1996)).Usually the calculated noise levels are converted to colours an depicted as a map. [Figure - 1] and [Figure - 2] show noise map (City of Birmingham) for road and rail noise. The maps are covering only a small part (1 km2) of the whole area of 330 km2.
Instead of calculating a combined noise map like [Figure - 3], a combined annoyance map can be calculated, depicting the annoyance potential. Since the relation between the annoyance potential and the noise level depends on the source type (road, rail, aircraft) the combined annoyance map can not be derived from the combined noise map. One way to produce a combined annoyance map is to calculate the annoyance potential for each source type as for example, given in 'Response function for environmental noise in residential areas' (Response function for environmental noise, TNO Report, H.M.E. Miedema, 1992). and then „add" the annoyance potentials. The combined annoyance; PCAn, of n noise sources can be calculated - under the assumption that the annoyance of the different noise sources are only weakly correlated - as
P J : annoyance for source j in %/100
The combined annoyance, for example, of 3 sources with an annoyance of 5%, 7% and 11% are:
PCA3 = 100• (0.05 + (1-0.05) •0.07 • (1-0.05-0.07)
.11) % = 21.4 %
[Figure - 4] shows the annoyance calculated for the noise levels shown in [Figure - 3].
Combining the annoyance potential with the distribution of the population, the actual number of people annoyed by the noise sources can be calculated. From such a map the effects of noise reduction measures, for example, can be easily seen by the number of effected people. The example in [Figure - 5] shows the distribution of highly annoyed people. The squares are 50x50 m and corresponds to the distribution of the population.
| Summary|| |
Noise maps showing the distribution of ambient noise levels covers the various aspects in protecting the environment from noise. In combination with empirical studies on annoyance noise mapping is a ideal tool for planning and cost assessment of noise protection. Furthermore, the calculations are a good basis to investigate empirical studies on annoyance.
| References|| |
|1.||Calculation of Road Traffic Noise, Department of Transport Welsh Office, HMSO, 1995 |
|2.||Guide du Bruit des Transports Terrestres, Prevision des niveaux sonores, Ministre de L'Environment et du carde de vie, Nov. 1980 |
|3.||ISBN 2.11.083290 8ISO 9613-2, Acoustics- Attenuation of sound during propagation outdoors. Dec. 1996 |
|4.||Miedema, H.M.E. (1992) Response function for environmental noise, TNO Report. |
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Source of Support: None, Conflict of Interest: None
[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5]