Facts
Parties and procedural history:
The Swisscom (Schweiz) AG (hereinafter: Swisscom) filed an application for construction with the Building Division of the City of Zurich for the expansion and modification of an existing mobile radio antenna system. The system was to transmit on the frequency bands 700–900 MHz, 1'400–2'600 MHz and 3'600 MHz and in the azimuths 40° and 130°. In the 3'600 MHz frequency range, the antennas were to operate adaptively with 16 sub-arrays each, with the cumulative transmission power amounting to 700 WERP and to be distributed across the transmission directions 40° (300 WERP) and 130° (400 WERP).
The Building Division of the City of Zurich granted Swisscom the requested construction permit by decision dated 20 October 2021. A. filed an appeal against this decision with the Building Appeals Court of the Canton of Zurich, which dismissed the legal remedy by decision dated 6 May 2022. The appeal filed by A. against this decision was also dismissed by the Administrative Court of the Canton of Zurich on 12 May 2023. A. filed an appeal against the administrative court judgment with the Federal Supreme Court (1C_307/2023) on 20 June 2023 in public law matters.
Facts and subject matter of the dispute:
The central issue in the proceedings is whether the provisions in the Ordinance on Protection from Non-Ionising Radiation (NIRO) concerning adaptive mobile radio antennas – in particular the application of a correction factor (KAA) to the maximum transmission power and the averaging of the transmission power over 6 minutes – are compatible with the precautionary principle under environmental law (Art. 11 para. 2 EPA). In addition, the suitability of the existing quality assurance system (QA system) for monitoring the operation of such antennas in compliance with the permit is discussed.
The adaptive antennas in dispute were to be operated with a correction factor KAA of ≥ 0.20 pursuant to para. 63 subpara. 2 and 3 Annex 1 NIRO. A. challenged in particular the legality of these provisions and the unsuitability of the QA system for monitoring compliance with the limit values.
Considerations
1. Legal basis and precautionary principle:
The Federal Supreme Court first examined the legality of the provisions on the correction factor and the averaging of transmission power contained in para. 63 Annex 1 NIRO. Pursuant to Art. 11 para. 2 EPA, emissions must be limited as far as technically and operationally feasible and economically reasonable, irrespective of the existing environmental burden. The NIRO specifies these requirements by means of system limit values that must be complied with for fixed mobile radio systems at all locations with sensitive use (LSU). These limit values serve as a safety margin in relation to the immission limit values and are intended to minimise the risk of harmful effects (para. 3.1).
2. Delegation authority of the Federal Council and proportionality:
The Federal Supreme Court confirmed that the Federal Council was authorised under Art. 38 para. 3 EPA to issue the contested provisions in the NIRO. The regulation of the correction factor and the averaging of transmission power over 6 minutes constitutes a technical calculation method that the Federal Council may establish to specify the system limit values. The delegation is proportionate as it remains within the scope of the statutory authorisation and does not entail any serious interference with the legal position of those affected. Moreover, the regulation at ordinance level allows for flexible adaptation to new technical developments (paras. 5.1–5.4).
3. Compatibility with the precautionary principle:
The appellant argued that the regulation leads to a preferential treatment of adaptive antennas over conventional antennas and lowers the level of protection. The Federal Supreme Court dismissed this objection. Adaptive antennas are characterised by dynamic adjustment of the transmission direction and the antenna diagram (“beamforming”), which focuses the radiation specifically towards the users. As a result, the average radiation exposure in the vicinity of such antennas is lower than with conventional antennas. The correction factor and the averaging of the transmission power over 6 minutes take this circumstance into account by preventing adaptive antennas from being assessed more strictly than conventional antennas. The regulation thus does not lower the level of protection but ensures that the existing level of protection is maintained (paras. 6.1–6.4).
The Federal Supreme Court based its decision on scientific studies and measurements by the FOEN, which show that the transmission power of adaptive antennas averaged over 6 minutes is in the vast majority of cases significantly below the maximum transmission power. The correction factor was derived on the basis of the 95th percentile of realistic maximum outputs and ensures that power peaks only occur briefly and that the safety margin in relation to the immission limit values is maintained…