According to scientists, tobacco contains hundreds of complex chemical components, most of which are harmful to human body. Among them, 40 kinds of tar, nicotine, phenols, alcohols, acids and aldehydes are toxic and carcinogenic. After the cigarette is lit, the smoke produced contains all the chemical components in tobacco, and at the same time, it also adds some harmful substances to tobacco itself, such as carbon monoxide and cigarette tar.

This is because in the process of making cigarettes, in addition to the tobacco itself, some substances such as cocoa, licorice, sugar, glycerol and ethylene glycol are added to the raw materials. Although these additives are harmless in themselves, they have changed during combustion. For example, when the back of a mouse is coated with smoke oil produced by cocoa burning, skin tumors will grow. Glycyrrhizic acid in licorice. After combustion, it can be combined with other components to generate carcinogenic polycyclic aromatic hydrocarbons.

When sugar is burned with tobacco, the tar content increases, and the products of sugar combustion are important carcinogens in tobacco. After burning, substances such as glycerol and ethylene glycol may not only make smokers suffer from bladder cancer, but also produce acrolein, which inhibits the discharge of tracheal and ciliary secretions from the lungs, thus increasing the chances of suffering from tracheitis and emphysema and aggravating the conditions of people suffering from these two diseases.

Smoking index

The calculation method is as follows:

Smoking index = number of cigarettes per day × number of years of smoking.

If you smoke an average of 20 cigarettes a day for 20 years, then your smoking index is 400. If you smoke 30 cigarettes a day, your smoking history is 15 years and your smoking index is 450. Medical scientists list people who smoke more than 400 cigarettes as "high-risk groups" of lung cancer. Therefore, during the period of 50-59 years old, lung cancer is the most common, and the incidence of lung cancer over 40 years old continues to rise.