Bleed air is (on any airliner except 787) what you are breathing in the cabin whenever the doors are closed and ground AC equipment is removed, so your post was

Bleed air is (on any airliner except 787) what you are breathing in the cabin whenever the doors are closed and ground AC equipment is removed, so your post was implicitly about bleed air. It’s the air that is “pumped into the cabin”. Exhaust and oil fumes both get into cabin air through non-normal situations. They’re not “pumped in by airlines”, and suggesting that they are (or that they stopped for a while and then started again thinking nobody would notice) is sensationalist and incorrect.