Noise level Lden of the main railway axes in Wallonia - 2017 report

This data layer locates the noise exposure from the main railway axes (more than 30000 train passages 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. In the Lden calculation, the ‘Levening’ and ‘Lnight’ indicators are weighted to take account of the fact that, at the same level, we are more sensitive to noise during these periods: - +5 dBA in the evening period, which means that a vehicle travelling in the evening is considered equivalent to almost three vehicles travelling during the day; - +10 dBA at night, which means that a vehicle travelling in the evening is considered equivalent to almost ten vehicles travelling during the day. According to the criteria defined for the mapping of noise emanating from the main railway axes, the data layer covers only those sections of railway lines for which rail traffic is 30,000 or more train crossings per year. The data layer is a vector layer with, as an attribute, the value Lden. 6 exposure classes are mapped: less than 55, 55-59, 60-64, 65-69, 70-74 and more than 75 dB(A). The low and high values of the exposure class concerned shall be recalled as an attribute. The value class of less than 55 decibels shall not be exposed at the level of the visualization service. The indicator is averaged over a calendar year. The data layer is therefore representative of a regional annual situation. The noise maps of the main railway axes were drawn up on the basis of source data dating from 2014 (SNCB transport plan - December 2014) or collected in early 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.