Wanted: air purifier for the home

Ross writes: I'm currently looking for an air purifier for my home. I'm a single dad and my little girl comes to stay with me every weekend. I don't smoke in the house from Friday (she comes Sat morning) until I take her back to her mum on Sunday but I know it's not healthy her breathing in any lingering smoke.

I often smoke outside during the week for this reason but, let's be honest, that's not always great in this country with its weather and sometimes you want to sit down with a coffee and a fag. Our inclement climate is also the reason why my usual fallback of opening the window as often as possible isn't always advisable.

I'm trying to find a good, relatively-small, air purifier that will remove the smoke and the airborne tar. I live in a relatively small cottage so I don't need some massive industrial-sized unit and I don't smoke upstairs at all, so essentially it needs to cover the lounge and the kitchen which are joined.

I can find 1001 different "purifiers" on the Internet but, obviously, each has their benefits and my quite specific requirements aren't covered in the sales blurb! I'd appreciate any advice or pointers you can give. Of course, I could give up.