If its a kerosene smell its jet exhaust.

If it smells like a wet dog that is engine oil that is burned up and getting into the airconditioner pax and that stuff is "no bueno".

I think Alaskan has a lawsuit against them now from FA's having health problems.

This problem is common to all aircraft, scarebus, or boeing. The root cause is bleed air that is used for airconditioning that can be contaminated with engine gases.