Newbie question - can I remove smell in the room without external extraction?

Just setting up a small grow, maybe three plants, in a small attic room that's about 6 ft square. It's all plasterboarded out though a good draught does get through.

I'll be using a Plantphotonics LED light so no worries on heat extraction.

The entrance to the room is right next to our bed, so I'm keen not to have the smell coming through to the bedroom.

Someone mentioned you can just pass the air in the room through a carbon filter without having it vented outside? Is this true as I would rather do this than worry about the extracted air smelling for the neighbours.

You can run internal scrubbers but you'll still need some sort of positive air exchange.

yep, you'll need to set up some kind circulation for fresh air exchange; even without heat issues your plants will need fresh co2 from somewhere. In the process you'll be able to scrub the air your venting. if you're in an attic, why not route a simple dryer vent w/ booster into the roof? just put a backdraft damper on the end so you don't get cold air blowing back in.
be easy,

You won't need a heavy air exchange system if you haven't a heat issue. Have a vent coming into the grow from outside and an exhaust vent. If you draft from inside the attic(house) and exhaust outside you could cause damage to the house.

Great, that all makes sense, thanks chaps, it'll be easy enough to get that sorted.