There are lots of reasons why you shouldn't smoke, most of them variants on 'it's bad for you' and 'it's anti-social'; the smoking ban that comes into force this July is something I'm looking forward to tremendously. Finally pubs will be bearable places! I think that smokers tend to underestimate just how horrible cigarettes are to non-smokers: smoking blunts your sense of smell, and gets you used to tobacco anyway; the fact that you can smell a smoker ten feet away even if he isn't smoking at the moment, or that one cigarette on the other side of a crowded room contaminates the whole place, is probably something they just aren't aware of. That, and the virulence of it; nothing lingers like the smell of cigarettes. It's like something creeps inside you and chews on your lungs, and if you spend one minute in a smoky room, the smell of it will linger in your clothes and hair until you wash them, for days.

So hooray for the smoking ban. But I'm currently living with a more direct experience of why smoking is unhealthy, and it has to do with redecorating my new house.

The previous owners were clearly heavy smokers. I first viewed the house last December. It was standing empty, and had been for some time, and yet the first thing I said going through the door was 'It stinks of smoke in here.' I moved in four months later, the house still having been empty and smoke-free all that time, and it still stank of smoke, even after I got the carpets shampooed. It was only when it came to stripping the walls that I realised the full extent.

The ceilings were discoloured, a kind of dingy beige marbling effect like the inside of a neglected teacup. I realised that those were smoke stains - but then we got out the steamer. And as the steam started loosening the paper, it also loosened the stains. Nicotine residue started dripping down, fat rusty globules that stained everything they touched, over everything. It's hard to describe just how revolting they were; it was like the house was sweating stale urine. All of which was because the previous owners smoked indoors, probably blithely unaware of the effect it was having.

If you've got a child and you want to put them off smoking, I've got the answer: send them round to my place when we're steaming the ceilings, point to the orange dribbles and say 'That's what the inside of your lungs will look like.' In fact, give them some paint and a roller and I'll let them in for free.

For anyone in the UK who's trying to quit, here's a website that gives you the location of your nearest NHS stopping-smoking service. Good luck to you.