Q) Oxygen masks are decoys, meant to keep passengers calm before a crash ?
A) This one, propagated by the character Tyler Durden in “Fight Club,” is way off the mark, according to Smith. If the cabin loses pressure (which can easily happen without leading to a crash), everyone on board is left breathing the air at 30,000 feet, which is oxygen-poor (the summit of Mt. Everest is 29,029 feet high). Until the pilots can bring the plane down to about 10,000 feet, where the air is safely oxygen-rich, those masks keep everyone breathing normally. That’s fairly important.
Q) Does recirculated air in planes spread diseases ?
A) This one seems logical, but Patrick Smith puts it to bed: The air circulates until eventually it is drawn into the lower fuselage, where about half of it is vented overboard. The remaining portion is run through filters, then re-mixed with a fresh supply from the engines, and the cycle begins again. Those underfloor filters are described by manufacturers as being of “hospital quality.” Boeing says that between 94 and 99.9 percent of airborne microbes are captured, and there’s a total change-over of air every two or three minutes, far more frequently than occurs in buildings. Do watch out, however, for germs left behind on surfaces like tray tables (consider bringing some sanitary wipes or hand sanitizer).