CERN is committed to limiting the impact of the Organization’s activities on the environment. Within the HSE Unit, this goal is achieved mainly by:

  • integrating pollution prevention, waste minimisation and conservation of resources into existing and planned activities in order to limit their environmental impact (environmental prevention and awareness);
  • carrying out an environmental monitoring programme, updated yearly and agreed upon with the Host States' authorities, aimed at measuring the physicochemical and radiological impact the Organization’s activities (environmental monitoring);
  • informing the Host States' authorities (France and Switzerland) of the results of the environmental monitoring programme and of any other relevant environmental matters.

Environmental Prevention & Awareness

Integrating environmental prevention and awareness in the Organization’s activities is part of the mission of the CERN Occupational Health & Safety and Environmental Protection (HSE) Unit. The HSE Unit strives to keep the impact of the Organization’s activities on the environment as low as possible. Legal requirements and best practices in environmental matters for existing and planned activities are typically identified by the HSE Unit and communicated to the CERN Departments concerned. The HSE Unit also carries out specific environmental studies according to the needs of the Organization and follows-up indicators, defined in collaboration with the CERN Departments, for relevant environmental domains.

Environmental monitoring

The CERN environmental monitoring programme carried out by the HSE Unit includes the control of both radiological and physicochemical parameters ensuring the monitoring of emissions into the atmosphere and the discharge of effluents into watercourses surrounding CERN sites. Besides measuring releases into the environment, the monitoring of stray-radiation linked to the operation of CERN's accelerators and associated experiments, is a significant domain of the environmental monitoring programme.

The environmental monitoring programme is defined on an annual basis by the environmental monitoring plan (EMP), according to accelerator operation and industrial activities carried out by the Organization. It includes on-line monitoring and continuous sampling, periodic instantaneous measurements, regular sample collections and numerous laboratory analyses carried out by the HSE Unit. The on-line monitoring stations and the various sampling points are spread all over CERN’s sites and in the surrounding municipalities.

The environmental monitoring plan (EMP) is both complementary and parallel to the monitoring plans of the Host States' authorities (France and Switzerland). It is considered as the reference document for the radiological and physicochemical monitoring carried out by CERN to check the Organization’s impact of its activities on the environment. It describes the methods, the instruments and their locations, the sampling places, the schedules related to environmental monitoring on and around CERN’s sites. The parameters monitored and the French and Swiss limits they shall comply with are also specified.

Some online radiological measurement data, concerning CERN and its neighbourhood, is also provided by Switzerland, the “Office fédéral de la santé publique (OFSP)” and by France, the “Institut de radioprotection et de sûreté nucléaire (IRSN)”. This information can be accessed at the two following addresses:


All data resulting from the on-line monitoring, the regular sampling and associated laboratory analyses are compiled in reports on a quarterly basis and distributed within the Organization and to the relevant Host States' authorities.

Annual reporting on radiological data is also provided by the environmental radiological experts to the Office fédéral de la santé publique (OFSP, CH) to contribute to their report: “Radioactivité de l’environnement et doses de rayonnements en Suisse”.

Reporting is also done on environmental incidents and their evolution to the Host States' addressees concerned.

For any questions related to the CERN on-line environmental monitoring, sampling and analysis, please contact: