title: Semi-volatiles in mainstream smoke delivery from select charcoal-filtered cigarette brand variants.
abstract: BACKGROUND
  It has been reported that charcoal added to cigarette filters selectively removes many of the more volatile chemicals, but it is not clear to what extent charcoal may reduce the delivery of important less volatile chemical constituents in mainstream cigarette smoke.
  
  
  METHODS
  We analysed machine-derived mainstream smoke deliveries (under three smoking regimens) for variants of a charcoal-filtered cigarette commercially test-marketed in the USA, focusing on selected polycyclic aromatic hydrocarbons (PAHs), phenols and tobacco-specific nitrosamines (TSNAs).
  
  
  RESULTS
  While charcoal-containing filters selectively removed lower molecular weight PAHs from mainstream smoke, they did not significantly remove the heavier and more toxic PAHs studied, such as benzo[a]pyrene, a known carcinogen. Likewise, charcoal-containing filters removed phenols and TSNAs from mainstream smoke to differing amounts depending on the compound, filter design and the smoking regimen.
  
  
  CONCLUSIONS
  The addition of sufficient charcoal to cigarette filters is known to remove many volatile compounds and can potentially reduce deliveries of certain semi-volatile compounds under some machine smoking regimens. Less volatile compounds, with a significant portion in the particulate phase, are less available for selective filtration by charcoal-containing filters than the more volatile compounds that reside predominantly in the gas phase.
authors.affiliation: Emergency Response and Air Toxicants Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Highway, NE MS F-47, Atlanta, GA 30341, USA. bhearn@cdc.gov
authors.forename: Bryan A
authors.initials: BA
authors.lastname: Hearn
authors.forename: Yan S
authors.initials: YS
authors.lastname: Ding
authors.forename: Christina
authors.initials: C
authors.lastname: Vaughan
authors.forename: Liqin
authors.initials: L
authors.lastname: Zhang
authors.forename: Gregory
authors.initials: G
authors.lastname: Polzin
authors.forename: Samuel P
authors.initials: SP
authors.lastname: Caudill
authors.forename: Clifford H
authors.initials: CH
authors.lastname: Watson
authors.forename: David L
authors.initials: DL
authors.lastname: Ashley
mesh_terms: D002273:Carcinogens / Q000032:analysis; D002606:Charcoal; D005374:Filtration / Q000379:methods; D006801:Humans; D019570:Inhalation Exposure / Q000009:adverse effects; D009538:Nicotine / Q000032:analysis; D009602:Nitrosamines / Q000032:analysis*; D010636:Phenols / Q000032:analysis*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D012906:Smoke / Q000032:analysis*; D012907:Smoking; D014026:Nicotiana
chemical_list: D002273:Carcinogens; D009602:Nitrosamines; D010636:Phenols; D011084:Polycyclic Aromatic Hydrocarbons; D012906:Smoke; D002606:Charcoal; D009538:Nicotine