Childhood Asthma/Tobacco Smoke

Introduction

Characteristics

Fate and Transport

Exposure Pathway

Methods for Monitoring in the Environment

Methods for Measuring Human Exposure

Strategies for Preventing or Controlling Exposure


Respiratory Harmful Effects

Deposition, Absorption, and Metabolism

Dose-Response Relationship

Organ Sites of Toxicity

Biomarkers

Risk Assessment/Risk Management Considerations

References

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Fate and Transport of Environmental Tobacco Smoke (ETS)

  • The compounds present in ETS are transported in the “smoke” or combination of vapors and particles produced in the combustion of the cigarette.

    o After passing briefly through the hot cone, most of the carbon monoxide is oxidized to carbon dioxide, likely due to the high temperature gradient and sudden exposure to environmental oxygen.

    o Due to the lower temperature in the burning cone of the smoldering cigarette, sidestream smoke (the major contributor to ETS) has higher concentrations of some toxic substances than mainstream smoke (i.e., carbon monoxide and carbon dioxide). The lower peak temperatures between puffing results in oxygen deficiency and thermal cracking of molecules, thus less there is less complete combustion of tobacco.

  • The chemical composition and physical characteristics of ETS becomes transformed once diluted and dispersed in a room. This includes the volatilization of nicotine, a decrease in the size of particles, and the transformation of nitrogen oxide to nitrogen dioxide.

  • Constituents of the vapor phase remain in the ambient air for longer periods of time. Many of the VOCs (such as aldehydes) remain in the air for at least four hours after a cigarette has been smoked indoors, not undergoing any significant chemical reactions.

  • ETS is transported via air and is inhaled into the lungs