title: Volatile Organic Compound Emissions from Humans Indoors.
abstract: Research on the sources of indoor airborne chemicals has traditionally focused on outdoor air, building materials, furnishings, and activities such as smoking, cooking, and cleaning. Relatively little research has examined the direct role of occupant emissions, even though this source clearly contributes to indoor volatile organic compounds (VOCs) and influences indoor chemistry. In this work, we quantify occupant-related gaseous VOC emissions in a university classroom using a proton-transfer-reaction time-of-flight mass spectrometer. Time-resolved concentrations of VOCs in room air and supply air were measured continuously during occupied and unoccupied periods. The emission factor for each human-emitted VOC was determined by dividing the occupant-associated source rate by the corresponding occupancy. Among the most abundant species detected were compounds associated with personal care products. Also prominent were human metabolic emissions, such as isoprene, methanol, acetone, and acetic acid. Additional sources included human skin oil oxidation by ozone, producing compounds such as 4-oxopentanal (4-OPA) and 6-methyl-5-hepten-2-one (6-MHO). By mass, human-emitted VOCs were the dominant source (57%) during occupied periods in a well-ventilated classroom, with ventilation supply air the second most important (35%), and indoor nonoccupant emissions the least (8%). The total occupant-associated VOC emission factor was 6.3 mg h-1per person.
authors.affiliation: Department of Civil and Environmental Engineering, University of California , Berkeley, California 94720-1710 United States.
authors.forename: Xiaochen
authors.initials: X
authors.lastname: Tang
authors.affiliation: Department of Environmental Science, Policy and Management, University of California , Berkeley, California 94720-3114 United States.
authors.forename: Pawel K
authors.initials: PK
authors.lastname: Misztal
authors.affiliation: Department of Civil and Environmental Engineering, University of California , Berkeley, California 94720-1710 United States.
authors.forename: William W
authors.initials: WW
authors.lastname: Nazaroff
authors.affiliation: Department of Civil and Environmental Engineering, University of California , Berkeley, California 94720-1710 United States.|Department of Environmental Science, Policy and Management, University of California , Berkeley, California 94720-3114 United States.
authors.forename: Allen H
authors.initials: AH
authors.lastname: Goldstein
mesh_terms: D000393:Air Pollutants; D016902:Air Pollution, Indoor; D004784:Environmental Monitoring; D010126:Ozone / Q000737:chemistry; D014691:Ventilation; D055549:Volatile Organic Compounds
chemical_list: D000393:Air Pollutants; D055549:Volatile Organic Compounds; D010126:Ozone