In the past ten years, the frequency of e-cigarettes has increased significantly, and e-cigarettes have emerged and become a popular alternative to traditional cigarettes. The National Institutes of Health's funding for tobacco research and e-cigarette publications is closely related, which proves the importance of e-cigarettes in tobacco research. In the past decade, the public generally believed that e-cigarettes are less harmful, and some health experts even pointed out the potential value of e-cigarettes in helping people quit smoking.

    However, the use and safety of electronic cigarettes are controversial. This controversy clearly shows that although the harm of traditional cigarettes has been fully proven, people still lack understanding of the safety of electronic cigarettes.

    An independent report from the Department of Public Health of the United Kingdom in 2015 concluded: “Although e-cigarette smoking may not be 100% safe, e-cigarettes do not contain most of the chemicals that can cause cigarette-related diseases, and the chemical substances contained are also harmful. Very limited". Only one-third of adults in the UK know that e-cigarettes are far less harmful than smoking. However, the fact is that the National Academy of Science, Engineering, and Medicine (NASEM) research has found that electronic cigarettes are far less harmful than traditional cigarettes.

    In February 2019, the National Institute of Health (NIHR) funded a large-scale clinical trial. The clinical trial involving nearly 900 participants found that e-cigarettes are twice as effective as nicotine replacement therapy (NRT) in helping smokers quit. An independent study by University College London (UCL) found that e-cigarettes help 50,000 to 70,000 cigarette users in the UK to quit smoking every year. The main components of e-cigarette oil are nicotine, propylene glycol and glycerin, as well as various flavorings. Unlike cigarettes, electronic cigarettes do not emit sidestream smoke into the atmosphere, but only release aerosols. At present, it has not been found that smoking electronic cigarettes will harm the health of people around