Funny canaries in the coal mine, not funny for safety and those who have become ill.
Ultrafine fine particle detectors look like the best option…
The thing is the sensors need to developed and the installation of ultrafine particle detectors should be really mandated by EASA and the FAA, to develop reliable sensors and have indications in the cockpit. Boeing and Airbus prefer to have sensors for maintenance only at the moment. From my point of view we pilots need to write our unions and the authorities on this issue. As the manufacturers and airlines fear lawsuits,etc theres a reluctance to admit the problem and advance safety in this issue.
Also..
“ several chemicals have been identified as having potential as markers for oil contamination.
60
“Potential marker chemicals representative of bleed air contamination
Chemical Potential
Formaldehyde Good
Acetaldehyde Good
Carbon Monoxide Fair
TVOC Fair
Carbon Dioxide Good
*Note: Good as a discriminator but not for primary detection
Various methods can be used to detect these gasses. These methods can be divided into four broad categories: 1) electro-chemical sensors, 2) metal oxide sensors, 3) photo ionization detectors, and 4) spectrometers.
The electrochemical sensors and the metal oxide sensors are relatively inexpensive and can be designed to target a variety of specific compounds. They have the potential for detecting low concentrations. Multiple sensors can be combined and tuned to detect specific substances. Some disadvantages include a tendency to drift over time, poisoning of the sensing medium, and slow recovery after exposure. Various measures may be employed such as cleaning cycles and calibration to address these concerns.”
Have a look this FAA document
https://rosap.ntl.bts.gov/view/dot/6..._62770_DS1.pdf
“The purpose of this project was to provide a data-driven process to identify sensing technology with good potential for detecting bleed air contamination from engine oil, hydraulic fluid, or deicing fluid. Reports from major aircraft cabin air studies were reviewed to identify the range of constituents that can be expected in cabin air, especially as they pertain to the aforementioned contaminants and their potential markers. One of the projects was the National Aeronautics and Space Administration Vehicle Integrated Propulsion Research (NASA-VIPR) project where controlled amounts of engine oil were injected into the engine compressor of a C-17 transport aircraft and the resulting contaminants in the bleed air measured. Three additional cabin air quality studies conducted on revenue flights were reviewed. These three studies provide data for a combined total of 249 flights on a variety of makes and models of aircraft. These studies provide adequate documentation of typical aircraft cabin air. Information from this review was used to identify potential markers of the bleed air contaminants. Additionally, collaboration was established with several technical committees from the Society of Automotive Engineers (SAE), American Society of Heating, Air-Conditioning and Refrigerating Engineers (ASHRAE), and American Society for Testing and Materials (ASTM) and with project personnel from the prior European Union Aviation Safety Administration (EASA)-funded cabin air study. Key objectives of the project were to identify sensors and sensing technology with potential for detection of one or more of the three aforementioned bleed air contaminants and to develop a plan for test stand engine experiments to evaluate the sensors with controlled amounts of the three contaminants. Sensors and instruments were identified and a test plan was developed. Additionally, through the collaboration with ASHRAE 1830 and the support of the industry working group, many of the experiments identified in the test plan were completed. The analysis of the data from these experiments is ongoing and will be reported in the ASHRAE 1830 project report. However, preliminary assessment of the sensing technology has been possible”.