A new monitoring strategy, referred to as temporal profile analysis (TPA), has been developed. TPA uses fixed-site, ambient air monitoring of volatile organic compounds (VOCs) to determine the number, VOC composition, and approximate trajectories of nearby source-related emissions. The strategy involves the interpretation of sequential ambient air gas chromatograms generated with sufficient frequency (hourly) to reveal the pronounced temporal variability of individual compounds. VOCs were monitored at a fixed site in the Richmond-Hopewell area of the Commonwealth of Virginia in September 1987 as a demonstration of TPA. The emissions from each of 12 nearby sources or source types were identified by comparing the prominent features in concentration time profiles. Two compound groups contain compounds usually associated with automotive emissions and as such constitute a VOC background that is generally prevalent in urban areas. All other groups, including one composed of Freon 12 and ethylene oxide, and a second composed of Freon 11, acetone, carbon tetrachloride, and sometimes chloroform are site specific. This monitoring strategy appears to be a direct and practical means to identify site-specific local sources and to improve mortality risk assessment. (Copyright (c) 1989 American Chemical Society.)