Help! Apartment ventilation randomly working??

[Simplesdiy]

I have lived in a apartment for 5 months and last night the -I'm assuming ventalition in the hallway (circular device in ceiling) randomly started to work and blowing in cold air, plus for a while smelly cooking scented cold air!
I haven't, as far as I know, flicked any switches etc so how do I get it off? It's boody freezing in here at the moment and there are no instructions or obvious switches/controls
Help required please!!

 

[AronSearle]

What?

Why does it smell of cooking, you say it's a ceiling fan, to a loft, why does you loft smell of cooking?

Does it have it's own switch on the fusebox, what about in the loft?

 

[Simplesdiy]

I live in a ground floor apartment, so no loft!

Also no switch on the fuse box, def no 'communal' switch in main lobby where fuse boxes are or switch in apartment

Any ideas? Thanks