Everyone has heard about how smoking is bad for your health. You’re thinking it’s only my body that’s affected, right? Wrong. Smoking can be damaging to those around you as well, especially if exposed chronically. Think of your children! But don’t forget about your pets.
Have you ever been inside a smoker’s house? It smells of stale smoke. Why? Because over time, there is a film that develops from all the pollutants in the air and it sticks to the walls, furniture, floor, and anything living there. We can always tell which pets have owners who smoke because their fur smells the same way. Smoking in a car is not much better, even if the windows are down as not all smoke will leave through the window and it is a small, enclosed space. Pets can be exposed to cigarette smoke not only by inhaling particles (Second hand) but also by absorbing it through the skin or ingesting particles that have landed on the fur (Third hand). Cats are at more of a disadvantage with being so close to the floor and being fastidious (thorough) groomers. Cats are at 2-3x higher risk of developing lymphoma if living in a home with a smoker.
Dogs tend to sniff the carpets and can inhale carcinogens through their nose. Exposure to cigarette smoke damages the DNA in back of the throat predisposing that area to cancer. Testing of airway and lung tissue shows increased inflammation and tissue damage and coal miner’s lung (anthracosis). The longer nosed dogs are at a higher risk of nasal carcinomas, where the brachycephalic breeds (short-nosed) dogs would be more prone to lung cancer. 
Irritants including pollens, pollution or cigarette smoke can trigger asthma attacks in humans. Studies show it affects animals, too. One of the first things your veterinarian will ask if your pet comes in for wheezing or cough is if there were any diffusers, aerosol sprays, or cigarette smoke in the house.
The nicotine metabolite is seen in the urine of pets exposed to cigarette smoke, indicating they are processing the toxic nicotine chemical without actually inhaling the cigarette itself. E-cigarettes/vaping may not have the same tarry carcinogens, but they still carry the nicotine. Some are flavored as well which may make them more enticing to animals. If an animal ingests any of the liquid from an e-cigarette, they are exposed to excessive amounts of nicotine which can be acutely fatal.  Pets should be kept away from nicotine patches, nicotine gum, and chewing tobacco for similar reasons.
Marijuana toxicity is becoming increasingly more common in areas where marijuana has been legalized. Marijuana may be legal, but the effects can still be very toxic to animals exposed to large quantities, whether by ingestion or inhalation. Those used in baked treats are especially enticing to dogs. In addition to the normal clinical signs of being high, they may also experience irregular heart rate, trouble walking, agitation, vomiting, trembling, seizures, inability to regulate body temperature, and coma. There is no specific antidote for marijuana toxicity so treatment is based around supportive care. 
If you suspect nicotine poisoning or marijuana toxicity, please seek help from your veterinarian or Pet Poison Hotline at 200-213-6680.
 Exposure to cigarette smoke causes DNA damage in oropharyngeal tissue in dogs. Mutat Res Genet Toxicol Environ Mutagen. July 2014;769(0):13-9.
 Stop smoking - for your health and your pets’ health. AVMA. 2019
 Marijuana toxicity in pets. PetPoisonHelpline. 2019
Written by Dr. Emily Russo-Moon