title: Contribution of human-related sources to indoor volatile organic compounds in a university classroom.
abstract: Although significant progress has been made in understanding the sources and chemistry of indoor volatile organic compounds (VOCs) during the past decades, much is unknown about the role of humans in indoor air chemistry. In the spring of 2014, we conducted continuous measurements of VOCs using a proton transfer reaction mass spectrometer (PTR-MS) in a university classroom. Positive matrix factorization (PMF) of the measured VOCs revealed a 'human influence' component, which likely represented VOCs produced from human breath and ozonolysis of human skin lipids. The concentration of the human influence component increased with the number of occupants and decreased with ventilation rate in a similar way to CO2, with an average contribution of 40% to the measured daytime VOC concentration. In addition, the human skin lipid ozonolysis products were observed to correlate with CO2and anticorrelate with O3, suggesting that reactions on human surfaces may be important sources of indoor VOCs and sinks for indoor O3. Our study suggests that humans can substantially affect VOC composition and oxidative capacity in indoor environments.
authors.affiliation: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.|Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA.
authors.forename: S
authors.initials: S
authors.lastname: Liu
authors.affiliation: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.|Department of Atmospheric and Oceanic Sciences, University of Colorado, Boulder, CO, USA.|Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA.
authors.forename: R
authors.initials: R
authors.lastname: Li
authors.affiliation: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.|Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA.
authors.forename: R J
authors.identifier: 0000-0002-4800-5172
authors.initials: RJ
authors.lastname: Wild
authors.affiliation: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.|Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA.
authors.forename: C
authors.initials: C
authors.lastname: Warneke
authors.affiliation: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.|Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: de Gouw
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA.|Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA.
authors.forename: S S
authors.initials: SS
authors.lastname: Brown
authors.affiliation: Department of Mechanical Engineering, University of Colorado, Boulder, CO, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Miller
authors.affiliation: Department of Mechanical Engineering, University of Colorado, Boulder, CO, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Luongo
authors.affiliation: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.|Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Jimenez
authors.affiliation: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.|Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: Ziemann
mesh_terms: D016902:Air Pollution, Indoor / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D006801:Humans; D014495:Universities; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D055549:Volatile Organic Compounds
keywords: Human occupants; Indoor air quality; Positive matrix factorization; Proton transfer reaction mass spectrometer; Skin lipid ozonolysis; Volatile organic compounds