Firstly, smoking in a public place should be banned because people who do not smoke are affected just as much as those who are smoking. This is due to second hand smoke, as the smoke emitted by a cigarette lingers in the air. Studies have shown that a single cigarette contains over 4,000 chemicals, with at least 50 of them being known carcinogens (Johnson, 2012). Carcinogen is a chemical, which is known to be directly linked to cancer.