title: Efficiency of log wood combustion affects the toxicological and chemical properties of emission particles.
abstract: BACKGROUND
  Particulate matter (PM) has been identified as a major environmental pollutant causing severe health problems. Large amounts of the harmful particulate matter (PM) are emitted from residential wood combustion, but the toxicological properties of wood combustion particles are poorly known.
  
  
  OBJECTIVE
  To investigate chemical and consequent toxicological characteristics of PM(1) emitted from different phases of batch combustion in four heating appliances.
  
  
  METHODS
  Mouse RAW264.7 macrophages and human BEAS-2B bronchial epithelial cells were exposed for 24 h to different doses (15-300 µg/mL) of wood combustion particles. After the exposure, cytotoxicity, genotoxicity, production of the inflammatory mediators (TNF-α and MIP-2) and effects on the cell cycle were assessed. Furthermore, the detected toxicological responses were compared with the chemical composition of PM(1) samples including PAHs, metals and ions.
  
  
  RESULTS
  All the wood combustion samples exerted high cytotoxicity, but only moderate inflammatory activity. The particles emitted from the inefficient phase of batch combustion in the sauna stove (SS) induced the most extensive cytotoxic and genotoxic responses in mammalian cells. Polycyclic aromatic hydrocarbons (PAHs) and other organic compounds in PM(1) samples might have contributed to these effects. Instead, water-soluble metals seemed to participate in the cytotoxic responses triggered by the particles from more efficient batch combustion in the masonry heaters. Overall, the toxicological responses were decreased when the combustion phase was more efficient.
  
  
  CONCLUSIONS
  Efficiency of batch combustion plays a significant role in the harmfulness of PM even under incomplete wood combustion processes.
authors.affiliation: Department of Environmental Health, National Institute for Health and Welfare, Kuopio, Finland. maija.tapanainen@thl.fi
authors.forename: Maija
authors.initials: M
authors.lastname: Tapanainen
authors.forename: Pasi I
authors.initials: PI
authors.lastname: Jalava
authors.forename: Jorma
authors.initials: J
authors.lastname: Mäki-Paakkanen
authors.forename: Pasi
authors.initials: P
authors.lastname: Hakulinen
authors.forename: Heikki
authors.initials: H
authors.lastname: Lamberg
authors.forename: Jarno
authors.initials: J
authors.lastname: Ruusunen
authors.forename: Jarkko
authors.initials: J
authors.lastname: Tissari
authors.forename: Jorma
authors.initials: J
authors.lastname: Jokiniemi
authors.forename: Maija-Riitta
authors.initials: MR
authors.lastname: Hirvonen
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D000818:Animals; D002244:Carbon / Q000032:analysis; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D054426:Chemokine CXCL2 / Q000378:metabolism; D004249:DNA Damage; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D008670:Metals / Q000032:analysis; D051379:Mice; D009153:Mutagens / Q000032:analysis / Q000633:toxicity*; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014934:Wood
chemical_list: D000393:Air Pollutants; D054426:Chemokine CXCL2; C404915:Cxcl2 protein, mouse; D008670:Metals; D009153:Mutagens; D052638:Particulate Matter; D011084:Polycyclic Aromatic Hydrocarbons; D014409:Tumor Necrosis Factor-alpha; D002244:Carbon