Under the Cantonal Airport Act, Flughafen Zürich AG is obliged to calculate the level of aircraft noise exposure caused by its actual flight movements.
Article 38 of the Noise Abatement Ordinance (NAO) stipulates that aircraft noise imissions must be determined by calculation. Such calculations are performed by the independent Swiss Federal Laboratories for Materials Testing and Research (EMPA).
Aircraft noise attributable to civil aviation is assessed according to Annex 5 of the NAO. The aircraft noise maps show areas where thresholds have been exceeded. The threshold curves with the day and night noise values are illustrated per sensitivity level for residential zones (SLII), mixed residential/industrial zones (SLIII) and industrial zones (SLIV).