Volatile Organic Compounds in Twelve California Office Buildings: Classes, Concentrations and Sources

Concentrations of total volatile organic compounds (TVOC) and of 39 individual volatile organic compounds (VOCs) were measured in 12 northern California office buildings of three different ventilation types. The objectives were to characterize indoor air exposures to VOCs, to investigate variations in chemical composition and concentrations among the buildings, and to identify potential sources of the VOCs. Indoor TVOC concentrations ranged from 230 to 7000 μg m⁻³ with a geometric mean of 510μg m⁻³. The highest TVOC concentrations were measured in two buildings with wet-process photocopiers. Geometric mean concentrations of individual VOCs were, with one exception, less than 5 ppb. There was considerable variation in the chemical composition of the VOC mixtures among the buildings. For most buildings, the oxidized hydrocarbons were the dominant class. Factor analysis identified motor vehicle emissions from outdoor air as a major source of seven aromatic and five alkane hydrocarbons. There was evidence of freon leaking from air conditioning or refrigeration systems in several of the buildings.