@MrDK
My point was that all of the suggested forms would be of interest, if "fume" is used generically, rather than technically, for all sorts of airborne and ingestible lubricant-related muck. I understand that "oil fume incident" tends to be used to cover all.
Hence a test will be difficult, since the offending material could be in this wide variety of forms: a gas, a mist of different sized drops with different compositions, as a mantle on solid smoke particles, within the smoke particles…
MrSnuggles' swab traveling along with you sounds like a good start, although the swab is dry and doesn't inhale. You'd also probably be best to run a control with a fresh one, and to try exposing them in other circumstances, far from engine oil. The same goes for your collection sampler, which would be better since it has an airflow.
Another problem would be potential loss of volatile materials from the filter during the hours after exposure, as the level likely isn't at all constant.