Sick Building Syndrome may be caused in part by volatile organic compounds (VOCs). One hypothesis is that the total volatile organic concentration (TVOC), rather than individual compounds, is a main factor in the syndrome. The TVOC level at which symptoms occur has been estimated to be in the range of 1-2 mg/cum, based on measurements employing GC-FID techniques. Very few measured data are available to determine the frequency with which homes and buildings in the United States may approach TVOC levels of this magnitude. However, data on 12-hour average values of individual VOCs from 750 homes and 10 buildings were available from EPA's TEAM Studies (1981-88). An initial study to determine the feasibility of obtaining a TVOC value from stored GC/MS data showed that TVOC estimated could be obtained with satisfactory precision ((+ or -) 30-60%). Therefore TVOC values were calculated from about 2700 personal, indoor, and outdoor air samples collected in the TEAM Studies.