Comment by mrguyorama

The conditions that trigger the "Fuel like smell" of kerosene is that you are in a place where thousands of gallons of actual kerosene are handled, moved, spilled, and burned every day.

The air quality at an airport is horrific, in general, and as long as the plane is on the ground, it will be moving that air into the cabin.

People notice it because you go from highly filtered, airport air, to unfiltered air on the jetway, to possibly filtered (depending on specifics) air from the ground equipment, to bleed pack air.

It goes away when you are flying because the air quality 4000 feet above the airport is so much better.

The oil seals in a jet engine are not magically perfect, and so there is absolutely some miniscule amount getting into bleed air. But bleed air comes out from the compressor section, before any fuel can be there, and modern jet engines are exceptionally good one way valves (compressor stall is the term for when they aren't). Engine oil consumption is also monitored for every single flight, but not to that level of precision.

If the smell goes away in the air, it cannot be related to small amounts of oil vapor coming from the engine compressor section. Because that would still be present at 30k feet.