Noise level Lden of the main roads in Wallonia - 2017 report

This polygonal data layer locates noise exposure exclusively from main roads (3 to 6 million vehicles per year) outside agglomerations according to the Lden index and integrated into the 2017 European report. The Lden index is one of the two indicators recommended by the European Directive 2002/49/EC, relating to the assessment and management of environmental noise, in order to measure the noise level describing environmental noise. Within the meaning of the Directive, the latter is emitted by means of transport, road, rail or air traffic or comes from sites of industrial activity. The Lden index stands for "Level Day - Evening - Night". It is therefore an indicator of the overall noise level for 24 hours (day, night and night) used to describe the discomfort associated with exposure to noise. It is calculated from the indicators "Lday", "Levening" and "Lnight", averaged sound levels over the periods 7h-19h, 19h-23h and 23h-7h. It is expressed in decibel A (dB(A)), which is the unit chosen to represent the sensitivities of the human ear. The lower noise limit to be reported for the Lden index is 55 dB. According to the criteria defined for the mapping of noise emanating from the main roads, the data layer covers only those regional road sections for which road traffic is between 3 and 6 million vehicles/year. Sections with road traffic in excess of 6 million vehicles were pre-mapped (2006). The data layer is a polygonal vector layer with, as an attribute, the value Lden. 5 exposure classes are mapped: 55-59, 60-64, 65-69, 70-74 and above 75 dB(A). The low and high values of the exposure class concerned shall be recalled as an attribute. The indicator is averaged over a calendar year. The data layer is therefore representative of a regional annual situation. The mapping of the main roads (3 to 6 million vehicles/year) was drawn up on the basis of source data dating from 2014 or collected at the beginning of 2015. Therefore, the data layers transcribe noise exposure to this period of time. The information was reported to the European Environment Agency in 2017 and therefore included in the 2017 report.