A carefully designed study was conducted during the summer of 1998 to simultaneously collect samples of ambient air by canisters and compare the analysis results to direct sorbent preconcentration results taken at the time of sample collection. A total of 32 1-h sample sets were taken, each composed of a "real-time" sample analyzed by an autoGC/MS XonTech 930/Varian Saturn 2000 system, and SUMMA and Silco canisters. Hourly total non-methane organic carbon (TNMOC), ozone, and meterological measurements were also made. Each of the canisters was analyzed on the autoCG/MS system for a target list of 108 VOCs and on a manual cryosampling GC/FID system. Comparisons are made between the collection and analysis methods. Because of the low sample loading (150-250 ppbC TNMOC), these comparisons are a stringent test of sample collection and analysis capabilities. This research was funded in part by the U.S. Environmental Protection Agency under Contract 68-D5-0049 to ManTech Environmental Technology, Inc. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.