Cigarette smoking and ethane exhalation in humans

Michael P. Habib, Neil C. Clements, Harinder S. Garewal

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


The time course of exhaled ethane gas was determined in the alveolar expirate of healthy, fasting smokers and nonsmokers after smoking a cigarette. Baseline ethane was measured by gas chromatography and corrected for background ethane after a 2-min washout using purified air. Ethane was measured immediately after smoking and hourly thereafter. Ethane was highest immediately after smoking, reflecting ethane in cigarette smoke. An exponential decline of ethane in smokers returned ethane to baseline within 3 h. Ethane in nonsmokers also peaked immediately after smoking but returned to baseline by 1 h. Ethane from smokers, measured 3 h after the last cigarette, was compared with ethane from healthy ex-smokers and nonsmokers. Mean (± SEM) baseline ethane in smokers was 2.90 ± 0.52 pmol/min/kg, 1.55 ± 0.36 pmol/min/kg in ex-smokers and 1.11 ± 0.26 pmol/min/kg in nonsmokers (p < 0.05). Ethane in two smokers measured before and after a week of oral beta carotene supplementation (60 mg/d) fell by 80 and 35%. We conclude that cigarette smokers have increased baseline ethane in exhaled breath compared with non-smokers. Trials with antioxidant agents are warranted to assess their ability to reduce expired ethane levels.

Original languageEnglish (US)
Pages (from-to)1368-1372
Number of pages5
JournalAmerican journal of respiratory and critical care medicine
Issue number5
StatePublished - May 1995
Externally publishedYes

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Critical Care and Intensive Care Medicine


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