Cabin Air Quality assessment of long-term effects of contaminants (CAQ III)

The quality of the air that passengers and aircrews are exposed to on board commercial transport aircraft has been at the core of a continuing debate for the past 60 years, both from the health and the safety points of view. This debate about cabin or cockpit air quality (CAQ) addresses most specifically single cabin or cockpit air contamination (CAC) events – e.g. due to potential oil leaks – and the intrinsic quality of the cockpit or cabin air in normal operating conditions.

A number of investigations and research projects have been conducted by various scientific teams, involving in-flight measurements, but so far have not allowed a complete characterisation of the chemical compounds involved in CAC events, determination of sources and exposure levels to contamination, nor performance of comprehensive toxicological risk assessment for such events.


The vision of the CAQ III project is to minimise current knowledge gaps in health risk assessment of oil-related “fume events” in aircraft in a reliable, efficient and cost-effective approach, bringing together the expertise and knowledge of all relevant disciplines and stakeholders. CAQ III will unite researchers, regulators and safety scientists from industry to reduce the uncertainties in risk assessment and enhance its practical applicability in line with the requirements of the regulatory authorities. In addition, the CAQ III partners will develop new mitigation strategies to better protect passengers and crew members in commercial aircraft from potentially hazardous chemicals.

The aim of the project is to provide a comprehensive physicochemical characterization of the compounds resulting from engine or APU (auxiliary power unit) oil leakage or dislodgment of deposits and their impact on cabin air quality. Such characterisation will be obtained through a series of measurements performed in controlled environments that are representative of flight conditions. 
The measured particulates and gases, their quantities, particle types and properties, their mixture and partitioning between gas and aerosol particulate phases will support identifying toxicological hazards and assessing exposure levels for crews and passengers.


CAQ III is a leading project to address the oil leakage-driven toxicological impact on cabin air quality and future risk assessments. Therefore, we ensure scientific excellence backed up by regulatory relevance by recruiting leading experts from academia, research institutions and large industry. Partners combine state-of-the-art expertise in human toxicology, exposure assessment, molecular biology, analytical chemistry, biostatistics, aeronautical engineering and chemical risk assessment, as well as expertise in management and dissemination.

The CAQ III project pools first-class knowledge for its envisaged systematic health effects studies on oil-related “fume events”: state-of-the-art inhalation toxicity testing (RIVM), neurotoxicological analysis and biomonitoring (HMGU, RIVM, NRCWE, InstPharmToxBw, Fraunhofer ITEM) and metabolomics screening (Fraunhofer ITEM). In addition, CAQ III aspires to create the broadest possible impact for cabin air quality assessment and thus operate within the realms of the main European regulatory bodies.

Role of RIVM

RIVM co-leads a work package on toxicity testing and biomonitoring. In this work package, a toxicity study addresses whether it is plausible that oil fumes generated using a so-called Bleed Air Contamination Simulator (BACS) can result in neurotoxicity after exposure by inhalation. The results will feed into a health hazard identification of contaminants identified in (simulated) oil-related fume events, performed in another work package. RIVM is also involved in communicating and disseminating CAQIII results and exchanging expertise between the consortium and relevant stakeholders. 

RIVM colleagues involved are Flemming Cassee, Jos van Triel, John Boere, Evert Duistermaat and Paul Fokkens.


This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No MOVE/B3/SUB/2020-243/SI2.826742.