When u smoke, it not just ruins your own health, but the health of other people that live with you. How? Well because cigarettes have a combination of bad chemicals that ruin your health, and when people inhale that smoke, they breath in those bad chemicals. But the smoker gets the most harm. How? Well smoking is very bad for your lungs. Like i have said , the smoker inhales the chemicals, and it goes to his lungs, because thats where he inhales it. and the lungs get the chemicals, and the more they smoke, the more the mungs get blacker, and untill you just get lung cancer.
Hope i helped!