This has been confirmed in a recent study carried out by Glasgow University. According to British scientists, dogs and cats living with owners who smoke double their risk of developing inflammatory airway diseases aswell as some kinds of cancer. The greater exposure of dogs and cats to cigarette smoke is principally due to the fact that our pets are more often in the homes of their owners, to whom they are often also physically close (nearby or held in their arms). Our little friends are more in contact, compared to humans, with areas of residual deposit. These residuals can also pass into their fur and then be swallowed during the animal's normal daily grooming activity. But the risks don't finish here.
Another dangerous eventuality is the ingestion of cigarette butts: nicotine, when swallowed, is in effect a real neurotoxic poison and it isn’t difficult for a dog to assume a potentially lethal amount seeing how attracted he is to human saliva.
It is obvious that the best solution would be to stop smoking. Alternatively, for those who don't want to give up smoking, it would be best to take some simple precautions, like smoking outdoors, ventilating rooms frequently and ensuring that ashtrays and cigarette butts are always out of reach of our four-legged friends.