I´m commercial pilot and from my 16 years experience, breathing toxic fumes has never been a real issue for crew members. The rate of medical discharges due to

I´m commercial pilot and from my 16 years experience, breathing toxic fumes has never been a real issue for crew members. The rate of medical discharges due to respiratory illness is equal or lower than I you can see in normal population (just my experience). We never talk about it, nor consider it a health factor. It´s true there is a moment when the engines start (there is fuel vapor that is not being burnt at the very beginning) when you can smell strong fuel fumes, they make their way to the packs (air conditioning system) but it only smells for a minute or so. Crews are very, very, VERY sensitive to smells, the worst emergency you can suffer in flight is a fire or smoke (electrical are the worst). We are always trying to discover and track any weird smell. We have procedures to isolate an air conditioning if it´s the cause of the smell or smoke (sometimes it happens). So no, I don´t think air quality it´s an issue in commercial planes. The air is very dry, and the recirculation and cabin altitude of 5k to 8k feet that create a lower oxygen partial pressure, in my opinion these are bigger factors in how you feel in flight than isolated contaminations. Also I must note that some flight attendants have some kind of urban legend were they come to cockpit and check the Flight level we are flying, then if it´s high (above FL320 or so) they start complaining about hipoxia and how tired they feel. Usually there is little difference in cabin pressure between FL320 and let´s say FL380, for example the cabin will keep around 8k feet for an Airbus A320 and 5k feet for an airbus A340 (cabin altitude is lower). I´ve tried several times to see if I can feel the difference somehow, but it´s almost impossible. I guess you need an aerobic test to feel it, or having some hipoxic condition due to an illness. I wouldn't be surprised if the people complaining from the quality of the air is the same one that complains of cabin altitude. But maybe they are right and there is an aerotoxic syndrome, I´m interested in seeing the results of a study. Personally I´m still more concerned about timezone changes 4-5 times a month, accumulated radiation, being bitten by malaria mosquito (when flying to Caribbean or Africa)or simply a van accident when being carried from the hotel to the airport. Edit: typo and clarification.