Environmental noise

Environmental noise is the summary of noise pollution from outside, caused by transport, industrial and recreational activities.

Noise is frequently described as 'unwanted sound', and, within this context, environmental noise is generally present in some form in all areas of human activity. The effects in humans of exposure to environmental noise may vary from emotional to physiological and psychological.

Noise at low levels is not necessarily harmful; environmental noise can also convey a sense of liveliness in an area, and is not then always considered 'unwanted'. However, the adverse effects of noise exposure (i.e. noise pollution) could include: interference with speech or other 'desired' sounds, annoyance, sleep disturbance, anxiety, hearing damage and stress-related cardiovascular health problems.

As a result, environmental noise is studied, regulated and monitored by many governments and institutions, as well as forming the basis or branch for a number of different occupations.

Noise from transportation is typically emitted by the machinery (e.g. the engine or exhaust) and aerodynamic noise (see aerodynamics and aircraft noise) caused by the compression and friction in the air around the vessel during motion.

Industrial and recreational noise could be generated by a multitude of different sources and processes.

Sound propagation outdoors is subject to meteorological effects (e.g. wind, temperature) that affect the distance, speed, and direction with which environmental noise travels from a source to a listener.

The European Union has a special definition based on the European directive 2002/49/EC article 10.1. This directive gives a definition for environmental noise. The main target is an integrated noise management.

The implementation is divided into phases: In the first phase the member states shall inform about major roads with more than six million vehicles a year, major railways with have more than 60,000 trains per year, major airports with more than 50,000 movements per year and agglomerations with more than 250,000 inhabitants. The second phase started with lower, partly the halve numbers. Only the criteria for airports remained unchanged. In the third and the following phases the methods for calculation the noise levels will change but the describd criteria remain unchanged. Each phase consists of three steps: the collection of the data about the main sources of noise as described before, strategic noise maps and action plans.

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