Abstract: The harm of smoking mainly comes from the harmful substances produced by the combustion of cigarettes, such as tar, polycyclic aromatic hydrocarbons, carbon monoxide, and cyanides. These substances could lead to various diseases including cardiovascular diseases, respiratory system diseases, cancer, and chronic inflammation. Therefore, it was urgent to reduce the harm of cigarettes and decrease the content of tar and other harmful substances. To this end, the generation patterns of harmful substances in cigarette smoke and the mainstream technologies for harm reduction and tar reduction were extensively explored. The application of numerical simulation techniques in cigarette combustion and harm reduction were introduced. Thereby providing both theoretical foundations and practical guidelines for a comprehensive understanding of cigarettes and related issues, as well as for reducing the health hazards of smoking.

Key words: composition of cigarettes, tobacco composition, pyrolysis and combustion characteristics of tobacco, cigarette smoke, hazard reduction and tar reduction, numerical simulation