The definition is also a special definition in the European directive 2002/49/EC article 10.1. This directive should give a common approach intended to avoid, prevent or reduce the harmful effects of environmental noise. The main target is an integrated noise management. In the first step the competent authorities in the European member states had to produce strategic noise maps for major roads, railways, airports and agglomerations. The second step is to inform and consult the public. The third step is producing local action plans to reduce noise.
The implementation is divided into two phases: The first important date was 30 June 2005 until "member states shall inform the Commission of the major roads which have more than six million vehicle passages a year, major railways which have more than 60,000 train passages per year, major airports and the agglomerations with more than 250,000 inhabitants within their territories". Major airports are defined as airports with more than 50,000 movements per year. The second phase starts with lower, partly the halve numbers so that major roads are defined as roads with more than three million vehicles, major railways with more than 30,000 trains and agglomerations with more than 100,000 inhabitants. The member states had to send informations about these datas to the Commission until 30 June 2010. The criteria for airports remained unchanged.
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.
In Germany recreational activities are not considered to be part of environmental noise. Germany has implemented national regulations in 2005 and 2006 and reported 27 agglomeration areas in the first phase: Berlin was the biggest with 3.39 million inhabitants and 889 square kilometers, Hamburg the largest with 1,045 square kilometers and 2 million inhabitants. The smallest was Gelsenkirchen with 270,000 inhabitants and 105 square kilometers. In the national legislation is recreational activities like sports and leisure noise are not considered as environmental noise.
United Kingdom 
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.
See also 
- Report from the Commission to the European Parliament and the Council concernig 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