Environmental noise

Like other industrial plants, the infrastructure needed to operate CERN’s large accelerators emits noise, especially when the accelerators are operational or undergoing maintenance. The main sources of noise at CERN are cryogenic installations, transformers, compressors, pumps, cooling towers and HVAC systems. In addition, mobile sources such as transportation and civil-engineering activities are also responsible for noise emissions.

CERN has an environmental noise reduction policy that sets out both preventive and corrective measures to avoid exceeding the existing noise levels (baseline year: 2018). Since the baseline was defined, CERN carries out yearly noise measurement campaigns in the vicinity of some 120 locations, during both daytime and night-time, to verify that the noise levels remain within the set limits.

Sources of noise, such as existing noisy infrastructure and equipment, are characterised, based on the ISO 9614-3 standard. The noise source data is then processed by a 3D georeferenced modelling software, CadnaA, which computes CERN’s environmental noise footprint with respect to the nearest residential areas. Mitigation measures are defined where needed, based on the results of the modelling.

Priority is given to reducing the noise at the source, for example by modifying the installations or replacing noisy equipment with quieter equipment. Patrols are also organised to detect malfunctioning equipment early. Should it prove impossible to make the modification for technical reasons, CERN instead implements mitigation measures, such as noise barriers and silencers.


Noise footprint reduction policy and implementation strategy.

Memorandum - CERN's noise emissions to the environment 

Noise barrier

A noise barrier put in place on a CERN site to reduce noise from industrial equipment.

Noise measurements being taken at Point 1 of the LHC.