It's the smell of turpentine which can get a little overpowering in a small space. You don't want to breathe in the fumes.
I used to do a lot of painting but I haven't done it in a long time. I had carpal tunnel surgery several years ago and my hand just hasn't been as steady.
It is a great hobby, though, and I encourage you to give it a shot! It's very relaxing and you get a real feeling of accomplishment creating art.