Stinky boot on 330D- exhaust fumes?

[shortshiftin]

Driving around in the 330 the other day and for the first time ever - no really - I had cause to put something in the boot.. and when I opened it I was greeted by what can only be described as an exhaust fume type smell...

...anyone else notice this?

the car had been parked up for a while so its not a residual smell from me pulling up and getting straight out.