Firstly, the principle of smoke production between the two is completely different. Cigarettes are burned through an open flame, and during the process of burning smoke and inhaling it into the lungs, they will bring substances such as tar and nicotine. Other overly professional terms such as benzene, pyrene, and hydrogen cyanide will not be mentioned separately. In short, they are all extremely harmful to the body. The main condition for the production of these substances is open flame combustion.
The principle of smoke generation in electronic cigarettes is to heat and evaporate the e-liquid, which can be understood as water vapor. Therefore, during the smoke production process, there is no tar or other substances brought about by the combustion of an open flame. But it also contains nicotine, and the amount of nicotine depends on the nicotine content in the e-liquid (cartridge) you use. This is marked on the e-liquid of all regular e-cigarettes, and usually the salesperson will tell you when selling, allowing you to choose the dosage independently.
Simply put, the main difference between the two lies in tar.