cigarettes any safer to smoke. Cigarette butt The common name for the remains of a cigarette after smoking is a cigarette butt. The butt is typically about 30% of the cigarette's original length. It consists of a tissue tube which holds a filter and some remains of tobacco mixed with ash. They are the most numerically frequent litter in the world. Cigarette butts accumulate outside buildings, on parking lots, and streets where they can be transported through storm drains to streams, rivers, and beaches. It is also called a fag-end or dog-end. In a 2013 trial, the city of Vancouver, British Columbia, partnered with TerraCycle to create a system for recycling of cigarette butts. A reward of 1¢ per collected butt was offered to determine the effectiveness of a deposit system similar to that of beverage containers. Electronic cigarette An electronic cigarette is a handheld battery-powered vaporizer that simulates smoking by providing some of the behavioral aspects of smoking, including the hand-to-mouth action of smoking, but without combusting tobacco. Using an e-cigarette is known as "vaping" and the user is referred to as a "vaper". Instead of cigarette smoke, the user inhales an aerosol, commonly called vapor. E-cigarettes typically have a heating element that atomizes a liquid solution called e-liquid. E-cigarettes are automatically activated by taking a puff; others turn on manually by pressing a button. Some e-cigarettes look like traditional cigarettes, but they come in many variations. Most versions are reusable, though some are disposable. There are first-generation, second-generation, third-generation, and fourth-generation devices. E-liquids usually contain propylene glycol, glycerin, nicotine, flavorings, additives, and differing amounts of contaminants. E-liquids are also sold without propylene glycol, nicotine, or flavors. The benefits and the health risks of e-cigarettes are uncertain. There is moderate-certainty evidence that e-cigarettes with nicotine may help people quit smoking when compared with e-cigarettes without nicotine and nicotine replacement therapy. However, other studies have not supported the finding that e-cigarettes are proven to be more effective than smoking cessation medicine. There is concern with the possibility that non-smokers and children may start nicotine use with e-cigarettes at a rate higher than anticipated than if they were never created. Following the possibility of nicotine addiction from e-cigarette use, there is concern children may start smoking cigarettes. Youth who use e-cigarettes are more likely to go on to smoke cigarettes. Their part in tobacco harm reduction is unclear, while another review