E-cigarettes are not completely harmless, but they are smaller than cigarettes; there is controversy as to whether e-cigarettes can quit smoking. Oxford Dictionary of the United Kingdom, the annual vocabulary is selected. In 2013, the vocabulary of the year was a selfie; in 2015, it was the crying and smiling emoji expression ""; in 2014, it was "vape", which is an electronic cigarette. From 2010 to 2014, the world's e-cigarette sales surged. However, for most Chinese people, e-cigarettes are a strange product. E-cigarette is regarded as a fashionable trend from foreign countries, and it is popular among a few people, although it is both invented by the Chinese and mostly produced in China. More people will only hear the news of e-cigarettes sporadically. For example, in October 2018, Hong Kong Chief Executive Lin Zheng Yue'e stated in his policy address that Hong Kong will completely ban the sale of e-cigarettes; for example, e-cigarettes have become a popular entrepreneurial project in the Mainland. What exactly is an electronic cigarette, and is it good or bad? Can electronic cigarettes really help quit smoking? E-cigarettes are harmful, but better than cigarettes. If you have been curious about the introduction of e-cigarette products, you may have seen some domestic merchants blowing e-cigarettes into medicine. They claim that e-cigarettes are "healthless", "clean" Lung detoxification. " You may have seen some other Chinese popular science articles that have gone through the hazards of various e-cigarettes, and some even claimed: "E-cigarettes are 7 times more carcinogenic than cigarettes!" Is e-cigarettes harmful? And, is electronic cigarette more harmful than traditional cigarettes? To answer these two questions, we must first briefly understand the structure of electronic cigarettes. Electronic cigarettes are usually divided into two major parts: electronic atomizers and nicotine-containing liquids (liquid oil). These two parts are similar to the relationship between pen and ink, syringe and medicine. The principle of e-cigarette is to atomize the e-liquid into nicotine smoke, and the smoker inhales the smoke like smoking. This kind of article is also called "vape" in English, sometimes called electronic atomizer. Of course, sometimes, electronic cigarette refers to a low-temperature flue-cured tobacco electronic cigarette, also called "IQOS", which will not be discussed here.