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Ventilation and air cleaning for pandemic preparedness

Clean Air For Everyone

CLAIRE is the acronym of the research project Clean air for everyone. In CLAIRE, we do scientific research to explore the potential of mechanical ventilation and air cleaning technologies to limit the adverse impacts of pandemics on health and well-being. Our consortium comprises research institutes, civil society organizations and innovative SME’s. Together we pursue a scientifically sound but practice-oriented approach to translate academic research outcomes into potential societal impact.

CLAIRE conducts experimental research into airborne transmission of viruses in indoor environments. CLAIRE develops measurement methods and risk assessment models. And CLAIRE engages with civil society organizations and the business community to explore what is needed for effective innovations in ventilation and air cleaning technologies to find broad application in practice.

CLAIRE’s primary focuses areas are primary schools and nursing homes. Both sectors were hit particularly hard during the COVID-19 pandemic. There is consequently a lot to be gained if effective deployment of ventilation and or air cleaning can help limit infections and reduce the need for painful limitations to care and education provision.

The CLAIRE research consortium is led by Utrecht University. The study is in full swing and will run until mid-2025.

Funding information

The Claire project is powered by Health~Holland, Top Sector Life Sciences & Health, through its Public-Private Partnership (PPP) Allowance programme.  Health~Holland is the trade name of the Dutch Top Sector Life Sciences & Health. Health~Holland is one of ten top sectors set up by the Ministry of Economic Affairs to harness Dutch innovation potential for a substantial contribution to global societal challenges. Show more

CLAIRE’s total research budget is approximately €4.3 million. Health~Holland contributes € 2.7 million to this. The rest of the budget is raised through in-kind contributions from the research partners.

For more about Health~Holland, visit

Contact us

Want to know more about our the CLAIRE project? Get in touch with researchers from the partner organisations? Alert us to your own research work? Don’t hesitate to drop us an email!

Access our scientific outline

For the benefit of fellow researchers in various disciplines, we have drawn up a complete methodological outline, detailing the research logic and set-up of the project and its various work streams and work packages. You can access the scientific outline here.

Design and objectives

Ventilation and air cleaning can help limit the spread of viruses (such as the SARS-CoV-2 virus) through the air in indoor environments, also known as airborne or aerogenic transmission. But there is currently insufficient insight into what performance requirements ventilation systems and mobile air cleaning systems must meet to contribute effectively to the prevention of airborne transmission.

CLAIRE develops practically applicable knowledge about the effectiveness of various interventions in indoor environments using deployment of ventilation, air cleaning systems and/or a combination of the two. Properties of air cleaners and ventilation systems are investigated, while aerosols and (infectious) viruses in the air are quantified. In addition to the architectural, technological and virological aspects, the feasibility and acceptability of the interventions are also examined.

Experimental research is conducted in real-life settings in primary schools and care homes (classrooms, communal areas such as living rooms). The project is organized into multiple research streams, which are strongly interconnected through use of uniform intervention scenarios, sampling and measurement methodologies and research settings across the streams.

The performance under realistic conditions of both ventilation systems and air cleaning technologies is investigated experimentally. Research set-up and objectives take into account possible interdependencies between ventilation systems and air cleaners. For both types of technology, CLAIRE’s research approach also looks towards the development of improved and easier-to-use measurement and modelling methods to assess and predict systems performance.

To build up knowledge on aerogenic dispersal patterns of and exposure risks to pathogens, sampling of indoor air will take place in a selection of test environments also used for the systems performance workstream. This research will make use of controlled release of inactivated and/or proxy viruses as well as sampling of naturally occurring viruses when appropriate and feasible. Sampling methodologies will be combined and optimized to improve reliability and representativeness of sampling outcomes. These measurements will be used as input for risk analysis models, which evaluate the risk of infection under the different interventions.

Sociological and psychological, mostly qualitative research methods will be brought to bear to investigate and map risk awareness, willingness and capability to invest, performance expectations and trust mechanisms among potential users (aged care providers and primary education trusts) of ventilation systems and air cleaning technologies to chart developmental avenues for mainstreaming and upscaling of effective solutions.

This public-private partnership provides a scientific basis to evaluate ventilation systems and air cleaning equipment during different intervention scenarios. The use and validation of effective indoor air interventions that are acceptable and fit-for-purpose for end-users is of great importance to Dutch society: not only in light of possible resurgence of SARS-CoV-2 variants, but also and especially as a means to be better prepared for future pandemic threats.

Research streams

The research in CLAIRE is organised into three research streams. You will find these fully explained in the scientific outline. In brief, this is what they are about.

  1. Measuring and predicting airflows
    How do airborne particles spread through indoor environments? How effective are ventilation systems and air cleaning technologies in removing particles? Which ambient factors affect dispersal patterns and removal effectiveness? What methods can be developed or improved for fast and reliable measurement and prediction of system performance? Three work packages are dedicated to these research issues.
  2. Exposure to biobased pathogens
    Airborne pathogens are notoriously hard to detect and quantify. CLAIRE’s microbiology based research stream works towards improved sampling methods and risk assessment models. Two work packages are dedicated to these objectives.
  3. Acceptability and implementation of interventions
    Broad implementation of new insights, methods and technologies is required to turn innovation potential into substantive societal impact. A knotty problem. Successful implementation of innovations requires both demonstrable effectiveness and trust and acceptance from end users. In this research stream CLAIRE explores underlying sociological and psychological mechanisms underlying trust and adoption.

Partner information

CLAIRE is carried by a consortium comprising 17 partner organisations. The consortium’s composition reflects the project’s distinctive practice-oriented approach. In addition to universities and research institutes, the CLAIRE consortium is home to a substantial number of innovative SME’s. Trade organisations representing both the business community and end-users are also part of the research team.

Universities and research institutes participating in CLAIRE
  • Utrecht University
  • Leiden University
  • Eindhoven University of Technology
  • The Netherlands Organisation for Applied Scientific Research TNO
SME’s part of the consortium
  • Euromate
  • PlasmaMade
  • Dolphine Global Trade Holding Ltd
  • Ultrasun International Ltd
  • Noa Air Ltd
  • Fellowes Benelux
  • Trox Nederland Ltd
  • WOLF Energiesystemen Ltd
  • JAGA Konvektco Nederland Ltd
  • Trotec
  • VFA Solutions
  • Habitat Solutions
Trade organisations participating in CLAIRE
  • Binnenklimaat Nederland
  • ActiZ
  • Stichting Binnenklimaattechniek