intact when it leaves the cigarette in MS about 2 seconds later. However, once emitted into SS and diluted to become an ETS component, nitric oxide is partially oxidized to nitrogen dioxide and progressively more oxidized as more time elapses, producing a potent hydrophilic nitrosating agent.


The smoldering of tobacco between puffs generates SS. Undiluted SS contains some toxic compounds in much higher concentrations than MS, especially ammonia, volatile amines, volatile nitrosamines, some nicotine decomposition products, and aromatic amines. Furthermore, decay products of radon from the tobacco and from other sources adsorbed on some particles in indoor air might contribute to the carcinogenic potential of ETS.

SS is a major contributor to ETS. Respiratory environments that are polluted with SS contain measurable amounts of nicotine and other toxic agents, including carcinogens. We lack data on the presence and concentrations of many of the known SS components in polluted, enclosed environments. The concentrations of toxic agents of ETS are governed primarily by the amount of tobacco smoked, the degree of ventilation, and the volatility of the agents. Future studies should concentrate on the analysis of toxic and carcinogenic agents in smoke-polluted environments.

What Is Known
  1. SS is the aerosol that is freely emitted into the air from the smoldering tobacco products between puffs.

  2. ETS consists of diluted SS, exhaled MS, smoke that escapes from the burning cone during puff-drawing, and vapor-phase components (such as carbon monoxide) that diffuse through cigarette paper into the environment. However, secondary reactions can occur before a nonsmoker inhales ETS, such as aging, volatilization of nicotine, and adsorption of radon daughters on particles.

  3. Undiluted SS contains higher concentrations of some toxic compounds than undiluted MS, including ammonia, volatile amines, volatile nitrosamines, nicotine decomposition products, and aromatic amines.

  4. Conventional cigarette filter tips primarily influence the yield of MS, but have little impact on the yield of SS. Highly

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