Facts
The municipal authority of Würenlos received a building permit for the construction of a sports facility. Several residents filed a complaint against the project. The Administrative Court of the Canton of Aargau commissioned an expert to prepare a noise assessment report and conducted a site inspection. Subsequently, the Administrative Court partially upheld both the complaint of the municipality and that of the private complainants. The municipality of Würenlos and the couple D. (private complainants) then filed an administrative court appeal with the Federal Supreme Court.Considerations
The Federal Supreme Court examined whether the approach proposed by the Federal Office for the Environment (FOEN) to clarify the noise situation was appropriate and lawful. It stated that the Noise Abatement Ordinance (NAO) does not contain limit values for all types of noise, particularly not for so-called "non-technical" everyday noise, such as that inherent in sports facilities. In such cases, the enforcement authority assesses the noise emissions in accordance with Art. 15 of the Environmental Protection Act (EPA), taking into account Arts. 19 and 23 of the EPA (Art. 40 para. 3 NAO). In this context, technically well-founded foreign guidelines, such as the German Noise Abatement Ordinance for Sports Facilities (18th BImSchV), can provide decision-making assistance, provided that the criteria are compatible with Swiss noise protection law. The FOEN recommended using the values of the 18th BImSchV for the assessment, as these better meet the requirements than Annex 6 of the NAO. It developed an assessment scheme to translate the values of the 18th BImSchV to the Swiss sensitivity levels. Based on this,…