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. This creates a number of different occupations. The basis of all decisions is supported by the objective and accurate measurement of noise. Noise is measured in decibels (dB) using a pattern-approved sound level meter. The measurements are typically taken over a period of weeks, in all weather conditions.
Environmental noise emission
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.
Environmental noise policy and regulation
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 more than 60,000 trains per year, major airports with more than 50,000 movements per year and metropolitan areas with more than 250,000 inhabitants. In the second phase, these numbers are halved; only the criteria for airports remains unchanged. In the third and the following phases, the methods for calculation of the noise levels will change while the criteria remain unchanged. Each phase consists of three steps: the collection of the data from the main sources of noise, strategic noise maps and action plans.
In Austria the institution which is responsible for the noise sources is also responsible for the noise maps concerning these sources. This means that the Federation is responsible for the federal roads and each state is responsible for the country's roads.
France reported 24 metropolitan areas, Paris was the biggest with 9.6 million inhabitants and 272 square kilometres.
Germany implemented national regulations in 2005 and 2006 and reported 27 metropolitan areas in the first phase: Berlin was the biggest with 3.39 million inhabitants and 889 square kilometres, Hamburg the largest with 1,045 square kilometres and 2 million inhabitants. The smallest was Gelsenkirchen with 270,000 inhabitants and 105 square kilometres. In the national legislation, noise resulting from recreational activities like sports and leisure is not considered as environmental noise.
The United Kingdom reported a total of 28 metropolitan areas, where London is the largest with 8.3 million inhabitants. The majority of metropolitan areas are located in England; in Scotland and Wales there are each two, in Northern Ireland only the capital Belfast.
- European Commission. "The Green Paper on Future Noise Policy" (PDF). Archived from the original (PDF) on 23 November 2010. Retrieved 7 September 2013.
- Kinsler, L.E., Frey, A.R., Coppens, A.B. and Sanders, J.V. (2000). Fundamentals of acoustics. New York City: John Wiley & Sons. p. 359. ISBN 978-0471-84789-2.
- World Health Organization. "Guidelines for community noise". Retrieved 7 September 2013.
- Report from the Commission to the European Parliament and the Council concerning Directive 2002/49/EC
- Directive 2002/49/EC of the European Parliament and of the Council of 25 June 2002 relating to the assessment and management of environmental noise