Does anyone know if there is a suitable detector for aircon fumes that we could use, a bit like the CO detectors in puddle jumpers? That way, when our airlines inevitably shut down a report citing a lack of evidence, or worse threaten a crew who diverted with disciplinary action for an event that they can't prove, we'd have some evidence? It really is a common event - I've had many similar experiences to Barkingmad's "altimeter check" at similar altitudes at idle on the 737 (classic and NG alike), despite it being an aircraft with a relatively good reputation (at least compared to the 146 and 75).