MIAMI, FL - FEBRUARY 20: Julia Boyle enjoys an electronic cigarette at the Vapor Shark store on February 20, 2014 in Miami, Florida. As the popularity of E- cigarettes continue to grow, leading U.S. tobacco companies such as Altria Group Inc. the maker of Marlboro cigarettes are annoucing plans to launch their own e-cigarettes as they start to pose a small but growing competitive threat to traditional smokes. (Photo by Joe Raedle/Getty Images)
