Empirical revision of noise mapping

Following the Directive 2002/49/EC the European States shall apply the day–evening–night level, Lden, among others, for revision of the strategic noise mapping. Definition of Lden is based on A-weighted long term average sound levels, Ld, Le, and Ln, which represent 365 days, evenings, and nights of a typical year. Lden approximation can be found from a few measurements of the A-weighted short term average sound levels, during the day-, evening-, and nights, Ldi, Lei, and Lni, where i = 1, 2, … , m ≪ 365. The uncertainty of Lden approximation is calculated.