Human history has been marked by respiratory disease epidemics and pandemics, some still ongoing, such as the seasonal flu and COVID-19. Virus-containing aerosol particles are thought to be the vehicle for spreading respiratory diseases, causing considerable human death tolls and impacts on every aspect of society. Understanding the links between environmental factors and virus infectivity are largely unknown, but understanding them is crucial to focus scientific research and technological efforts on solutions to minimize the infectivity of airborne virus indoors, and thus the spread of aerosol-borne diseases. Most often experiments are carried out in highly idealized conditions (such as in solution, in suspended large droplets or in rotating drum facilities. At EPFL we have developed a unique facility that generates particles from lung (and other) fluid that contain active viruses, and introduces them into a large chamber filled with indoor air to study their response to being airborne, exposed to characteristic atmospheric species and conditions for the purpose of developing appropriate indoor air treatment strategies for transmission risk reduction.

The LAPI BREATH is a novel biosafety level 2 aerosol chamber equipped with state-of-the-art instrumentation including aerosol generation via bubble bursting, size distribution measurement with a size classifier, and collection using condensational growth. The facility is thought to mimic a real airborne virus transmission scenario while minimizing inactivation when retrieving virus infectivity in aerosol particles. In the video you hear LAPI researchers Dr.Ghislain Motos and Dr.Celine Terretaz present the LAPI-BREATH and how it is used to study airborne viruses like the influenza virus (IAV). The facility:

• Features a voluminous chamber to respect natural aerosol settling, avoiding the use of fans or rotating instruments.
• Allows to study infectious viruses in aerosol particles, as well as any type of bioaerosols.
• Main research questions involve the impact of the aerosolization medium composition (saline solutions, saliva, lung fluid) and the air composition (gas-phase acids, organic compounds, NH3, etc.) on virus infectivity. These impacts are modulated by relative humidity.

Related activities include cultivation of virus and quantification of total genomic copies (PCR) & infectivity (plaque assay), carried out through a strong collaboration with the LEV@EPFL lab of Prof. Tamar Kohn. The group also strongly collaborates with Prof. Silke Stertz from University of Zurich, Dr. med. Walter Hugentobler and Prof.Tom Peter, Dr.Uli Krieger from ETH Zürich for modeling and other physicochemical aspects of the aerosols generated. The inner chamber was constructed in collaboration with the CSTACC team at the Institute of Chemical Engineering Sciences (FORTH/ICE-HT).

There is no other facility in Europe that can be used to study the behavior of Biosafety Level 2 viruses (e.g., influenza A, B) in a real atmospheric setting, for testing the response of airborne viruses to real atmospheric conditions – which in turn can be used to determine interventions (relative humidity levels, temperature, oxidants, acidity/alkalinity levels of the air) in response to epidemic and pandemics. With this facility, researchers and collaborators are at a strategically unique position to tackle questions related to airborne viruses, bioaerosols and their interaction with atmospheric constituents and conditions.

Select publications describing facility and its usage 

• Motos G, Schaub A, David SC, Costa L, Terrettaz C, Kaltsonoudis C, Glas I, Klein LK, Bluvshtein N, Luo B, Violaki K, Pohl MO, Hugentobler W, Krieger UK, Pandis SN, Stertz S, Peter T, Kohn T and Nenes A (2024) Dependence of aerosol-borne influenza A virus infectivity on relative humidity and aerosol composition. Front. Microbiol. 15:1484992. doi: 10.3389/fmicb.2024.1484992
• David, S.C., Schaub, A., Terrettaz, C., Motos, G., Costa, L.J, Nolan, D.S., Augugliaro, M., Glas, I., Pohl, M., Klein, L.K., Luo, B., Bluvshtein, N., Violaki, K., Hugentobler, W., Krieger, U.K., Peter, T., Stertz, S., Nenes, A., and Kohn, T. (2024) Stability of influenza A virus in droplets and aerosols is heightened by the presence of commensal respiratory bacteria, J. Virology, e00409-24, https://doi.org/10.1128/jvi.00409-24

History and projects supported to date by LAPI-BREATH

Swiss funding

• The chamber was established with funding from the SNF Synergia IVEA project, a consortium of groups between EPFL, ETHZ and UZH. A total of 15 people were part of this project, and the experiments in the aerosol chamber that were carried out were central to the IVEA outcomes.
• LAPI-BREATH plays a central role in 2 of the 3 WPs of the AirTRAC project, which involves the same consortium members of IVEA but also includes a group from Emory University. 
• The facility is also planned to be used as part of the Lipic-Air project funded by the SNSF, to generate and process bioaerosols and expose them to a number of oxidants and atmospheric stressors.

Horizon Europe funding

• The facility is used to help develop and test virus sensors as part of the SynAir-G project (https://actu.epfl.ch/news/prof-athanasios-nenes-wins-two-prestigious-grant-5/; https://cordis.europa.eu/project/id/101057271) by partners from CNR, Italy. LAPI is the coordinator of the sensor development package and the virus sensor is one of the innovations of the project which will be revolutionary for the characterization of virus levels inside buildings and can play a major role in battling future epidemics and pandemics.

Interviews, video editing & montage: Nikitas Diamantopoulos

Acknowledgments: Funding was provided by the Swiss National Science Foundation (SNSF) projects "IVEA" and “AirTRAC”, SNSF R'Equip funding and SERI/Horizon Europe under the SynAir-G projects. 

For more information, please visit the LAPI website or contact the LAPI director (Athanasios Nenes; athanasios.nenes@epfl.ch) or Dr Ghislain Motos (ghislain.motos@epfl.ch).