Moreover, there are many situations where noise is appropriate: for example a football Greatly and some people are not bothered by noise that would be intolerable to However, this presumption is by no means always true. Levels on the basis that any sound could be annoying to someone. This presumption is even the basis of some legislation, which often seeks to limit sound Will be someone who doesn’t like it, there is a common presumption that all sound isīad. Since it is quite probable that whatever the noise, there Person finds enjoyable, such as some music perhaps, could be very annoying to another Noise is often defined as ‘sound which is undesired by the recipient’. Legal rulings regulate what is consider audible, acceptable, allowable or significant. Set parameters for equipment limits, city, state or federal requirements. As part of modernĬivilizations standards and legal ruling have been developed and are continuously updated to Noise has a multitude of effects on our environment and society. Vivek Mariappan Environmental Engineer ConsultantĬontact (or) (or), Noise Mapping (Sound Level Modelling) This is particularly important in noise action planning, where a cost-benefit analysis of various options can be tested before a decision is made. Thus the effect of a proposed new road can be assessed and suitable noise mitigation can be designed to minimise its impact. Secondly, to obtain complete coverage of an area, measurements would have to be made on private property, where access might be difficult, and thirdly, measurements cannot distinguish the different sources of noise, so they would not be able to give information on how much noise was being made by each of the sources in an area.įor these and other reasons, noise mapping is usually done by calculation based on a computerised noise model of an area, although measurements may be appropriate in some cases.Ī further benefit of having a noise model is that it can be used to assess the effects of transportation and other plans. For a start, a long-term average must be measured over a long period of time. It may be thought that the best way of doing this is by measurement, but experience shows that this is not the case. This means that it is not possible to say with confidence what the noise level will be at any particular point at any instant in time, but where the noise sources are well-defined, such as road or rail traffic, or aircraft, then it is possible to say with some confidence what the long-term average noise level will be. In the longer term, wind, weather and season all affect noise levels. Then again, there is a greater volume of activity from more people and traffic in the day-time than in the evening or at night. In the slightly longer term, noise levels may be higher in peak periods when the roads are busy, and lower in off-peak periods. This would cause a short-term variations in noise level. For example, noise levels may rise as a vehicle approaches, and reduce again after it has passed. The noise levels over an area will be varying all the time.
Sometimes, the noise levels may be shown by contour lines which show the boundaries between different noise levels in an area. 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.A Noise Map is a map of an area which is coloured according to the noise levels in the area. 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.
In a second step using the distribution of the population the actual number of annoyed people can be evaluated. Under the assumption that the annoyance for the different sources are only weakly correlated, a combined annoyance map can be calculated. 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. Examples for noise mapping are Birmingham (GB), Linz (A) and various German cities. 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. This directive will make noise mapping mandatory for cities with at least 250.000 inhabitants. 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.