Urban Noise Pollution

The soundscape in a town or city has a huge effect on the quality of life there. The noise from traffic and transportation can affect our physical and psychological health.

This is why urban noise management and mapping are major concerns for urban planners, municipal officials, and politicians alike. And since reducing noise levels through traffic regulation, low-noise road surfaces or noise barriers is very expensive, it is best to avoid such measures where possible.

In short, preventing and reducing noise before it occurs, through noise-action plans, is the best way to minimize noise pollution from sources including wind farms and new roads.

Urban noise assessment

Assessment of urban noise from commercial properties or road traffic is the first practical step in urban noise management. The next stage is noise mapping, requiring the systematic charting of individual noise-source activity. Often, a large number of different sources contribute, so the impact of each specific noise source must be evaluated. These are fed into a calculation engine to create a range of noise metrics.

It is necessary to model the propagation of the noise including reflections from and attenuation of buildings and structures. These all greatly affect the noise levels experienced on the ground. Since this requires a large amount of information about the mapped area, it’s important that noise-capturing systems can interface with geographic information systems (GIS) and other management systems.

Environmental noise assessment

Environmental noise assessment is generally about evaluating the impact of one specific noise source, for example, the noise from a production plant. This is not easy as often a number of different sources contribute to the ambient noise at the measurement position.

For years, acousticians have attempted to quantify this to enable objective assessment of noise nuisances and implement acceptable noise limits. With large numbers of people, reactions tend to be distributed around a mean, and the rating level (or Lr) was developed to put a numerical value on a noise to quantify its annoyance in relation to the general population.

The rating level, defined in ISO 1996-1:2016, is a single value for evaluating the potential nuisance factor of noise. It takes into account type of source, time of day, nature of the noise (impulsive and pure tones present) and the overall level of noise. It compares measured levels with noise limits that usually depend on the use of the property under investigation. Almost all countries use the rating Level when assessing industrial noise.