Road noise – Exposed areas, over 24 hours (Lden indicator)

_\— _(see comment in the Admin section)_ _ _ ** ** **Strategic Noise Map** Data produced by Impédance engineering on behalf of the metropolis Aix-Marseille Provence ** ** **On the map, the geographical shapes have been simplified in order to optimise the display of the layer. The entire layer, without simplification of geographical shapes, is available in SHAPE format in the Export/Alternative Export tab.** The symbology associated with the noise map is available in the attachment in QGIS format Road noise according to the Lden indicator for type A maps on the Aix-Marseille Provence Metropolis. Results of acoustic modelling calculations. Type A map locates areas exposed to noise. The Lden indicator (for Level day-evening-night) represents the weighted average noise level during the day by giving a stronger weight to the noise produced in the evening (18-22h) (+ 5 dB(A)) and during the night (22h-6h) (+ 10 dB(A)) to take into account the increased sensitivity of individuals to noise pollution during these two periods.（详见管理板块中的注释） **战略噪声地图（Strategic Noise Map）** 本数据集由阻抗工程公司（Impédance Engineering）受艾克斯-马赛普罗旺斯都会区委托制作。 为优化图层显示效果，地图中的地理形状已做简化处理。未简化地理形状的完整图层可在「导出/备选导出」标签页中以SHAPE格式获取。 本噪声地图对应的符号系统已以QGIS格式附于附件中。 本数据集为艾克斯-马赛普罗旺斯都会区A型地图中基于Lden指标的道路交通噪声数据，系声学模拟计算结果。 A型地图用于标注受噪声影响的区域。 Lden指标（即昼夜等效声级，Level day-evening-night）为日间、傍晚及夜间时段的加权平均噪声级：针对傍晚（18时至22时）与夜间（22时至次日6时）的噪声，分别施加+5 dB(A)与+10 dB(A)的权重，以反映人体在这两个时段对噪声污染敏感度提升的实际情况。