Someone Smoking

I suspect someone who smokes in my house when I'm not there ... I see the ashes and it smells when I enter the house sometimes, but not hard proof on the defendant. Is there a material that stains when there nicotine in the air? Something to put in the vent which proves that the smoke has been filtered? Or perhaps another method? I want this to stop ...

You can always put up a couple of cameras ... I do not know everything that can detect it. but the way I think nothing is more convincing than the evidence video