The document discusses the different types of smoke produced by cigarette smoking and their effects. It identifies three types of smoke: mainstream smoke that is inhaled by smokers, sidestream smoke emitted from the burning end of cigarettes, and thirdhand smoke that remains on surfaces long after smoking. The document also outlines some key Philippine laws regarding cigarette smoking, including the Tobacco Regulation Act of 2003 which governs tobacco production and use and establishes smoking bans in public places and minimum age restrictions for tobacco sales. The Clean Air Act of 1999 is also mentioned as it relates to regulating smoke emissions.