Empirical revision of noise mapping

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