CAiMIRA is a risk assessment tool developed to model the concentration of viruses in enclosed spaces, in order to inform space-management decisions. It does this by simulating the airborne spread SARS-CoV-2 virus in a finite volume, assuming homogenous mixing for the long-range component and a two-stage jet model for short-range, and estimates the risk of COVID-19 airborne transmission therein. Please see the About page for more details on the methodology, assumptions and limitations of CAiMIRA.

The full CAiMIRA source code can be accessed freely under an Apache 2.0 open source license from our code repository. It includes detailed instructions on how to run your own version of this tool.


CAiMIRA is composed of two applications, the Calculator and the Expert App.


About page for details on methodology, assumptions and limitations of CAiMIRA.


Documentation for CAiMIRA, available here.


Official CAiMIRA GitLab repository.


CAiMIRA has been developed by CERN with the intention of allowing members of personnel with roles related to supervision, health & safety or space management to simulate the concerned workplaces on CERN sites. A hosted CERN version of the CAiMIRA Calculator is available on this site to members of the CERN personnel.

Reference & Citation

For use of the CAiMIRA model:

  • Henriques A, Mounet N, Aleixo L, Elson P, Devine J, Azzopardi G, Andreini M, Rognlien M, Tarocco N, Tang J. (2022). Modelling airborne transmission of SARS-CoV-2 using CARA: risk assessment for enclosed spaces. Interface Focus 12: 20210076.
  • Download citation
    Short-range expiratory jet model from:
    • Jia W, Wei J, Cheng P, Wang Q, Li Y. (2022). Exposure and respiratory infection risk via the short-range airborne route. Building and Environment 219: 109166.
For use of the CAiMIRA web app:
  • CAiMIRA – CERN Airborne Model for Indoor Risk Assessment tool
  • DOI
    © Copyright 2020-2021 CERN. All rights not expressly granted are reserved.
    Licensed under the Apache License, Version 2.0


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We wish to thank CERN at the different Departments working on the project: Occupational Health & Safety and Environmental Protection Unit, Information Technology Department, Beams Department, Experimental Physics Department, Industry, Procurement and Knowledge Transfer Department and International Relations Sector for their support to the study. We also wish to thank our collaborators at the World Health Organization (WHO) for thier endless support to this project, in particular to the members of the ARIA Expert Group.