Fourth-Hand Smoke?

- First-hand smoke: You smoke cigarettes, cigars, pipe, etc.

- Second-hand smoke: You are exposed to somebody's tobacco smoke.

- Third-hand smoke: You are exposed to the invisible yet toxic brew of gases and particles clinging to smokers’ hair and clothing.

- Fourth-hand smoke: You see through the window somebody smoking.

The fourth and last exposure to smoke was added as a joke by an experienced allergist. All forms of smoking are harmful however.

See this comment by a reader of the clinical case about bullous emphysema:

"My dad is fighting for his life at the hospital because of severe breathing difficulty. He has bullous emphysema. Why is this happening? Smoking. He's been a smoker since age 16, he is now 63, and he looks like a 93 year old man because of smoking. His last words before taking him to he hospital were: "I wish I could have a couple smokes."

References:
Bullous Emphysema
A New Cigarette Hazard: ‘Third-Hand Smoke.’ NYTimes.

Worldwide, 40% of children, 33% of male non-smokers, 35% of female non-smokers are exposed to second-hand smoke http://goo.gl/xFGef
Image source: Wikipedia, Tomasz Sienicki, Creative Commons Attribution ShareAlike 2.0 License.