Cabin crew: we highly recommend that you invest in a fullface respirator with cartridges, which would give you protection in the case of fume events (cockpit crew have their O2 full-face masks). The only 100% protection is possible by wearing a hazmat suit with integrated CO cartridges and pressurised O2 - that way the wearer is cut off from the environmental pollution and safe.
Please check out specialised companies such as i.e. 3M, Dräger, Honeywell etc. and view a couple of examples below.
The appropriate colour code would be according to the contaminants we know about: brown /filter type Nr 2. Also the "Bundeswehr Schutzmaske M65" (by Dräger) would be helpful.
Better suited is a civil mask like the "Dräger X-plore 6300 Full Mask". It has a standardized 40 mm threaded filter connection. A suitable filter would be the "Dräger X-plore A2B2E2K2HGP3". This is a "combined filter" for "organic gases and vapours" (A), "inorganic gases and vapours" (B), and other substances.
Personally we would carry a foldable one on our body (pocket) for the emergency case to pop it on while fetching the fullface respirator out of your flight bag.
Filter Selection Guide
A wider choice of contaminants is offered by Dräger VOICE 5.0 database of hazardous substances. With Dräger VOICE, you have the unique option to search for approx. 1,750 contaminants and their chemical properties in a compact database.
Note: no affiliation with mentioned company