title: Variability among electronic cigarettes in the pressure drop, airflow rate, and aerosol production.
abstract: BACKGROUND
  This study investigated the performance of electronic cigarettes (e-cigarettes), compared different models within a brand, compared identical copies of the same model within a brand, and examined performance using different protocols.
  
  
  METHODS
  Airflow rate required to generate aerosol, pressure drop across e-cigarettes, and aerosol density were examined using three different protocols.
  
  
  RESULTS
  First 10 puff protocol: The airflow rate required to produce aerosol and aerosol density varied among brands, while pressure drop varied among brands and between the same model within a brand. Total air hole area correlated with pressure drop for some brands. Smoke-out protocol: E-cigarettes within a brand generally performed similarly when puffed to exhaustion; however, there was considerable variation between brands in pressure drop, airflow rate required to produce aerosol, and the total number of puffs produced. With this protocol, aerosol density varied significantly between puffs and gradually declined. CONSECUTIVE TRIAL PROTOCOL: Two copies of one model were subjected to 11 puffs in three consecutive trials with breaks between trials. One copy performed similarly in each trial, while the second copy of the same model produced little aerosol during the third trial. The different performance properties of the two units were attributed to the atomizers.
  
  
  CONCLUSIONS
  There was significant variability between and within brands in the airflow rate required to produce aerosol, pressure drop, length of time cartridges lasted, and production of aerosol. Variation in performance properties within brands suggests a need for better quality control during e-cigarette manufacture.
authors: Department of Cell Biology and Neuroscience, University of California, Riverside, CA 92521, USA.
authors: Monique
authors: M
authors: Williams
authors: Prue
authors: P
authors: Talbot
mesh_terms: D000280:Administration, Inhalation; D000336:Aerosols; D003132:Commerce; D004581:Electronics; D004867:Equipment Design; D006801:Humans; D009330:Nebulizers and Vaporizers; D009538:Nicotine / Q000008:administration & dosage*; D011312:Pressure; D012907:Smoking; D014030:Tobacco, Smokeless
chemical_list: D000336:Aerosols; D009538:Nicotine