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TEMPORAL VARIABILITY MEASUREMENT OF SPECIFIC VOLATILE ORGANIC COMPOUNDS
Citation:
Pleil, J., W. McClenny, AND K. Oliver. TEMPORAL VARIABILITY MEASUREMENT OF SPECIFIC VOLATILE ORGANIC COMPOUNDS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-89/313 (NTIS PB90198581).
Description:
Methodology was developed to determine unambiguously trace levels of volatile organic compounds as they vary in concentration over a variety of time scales. his capability is important because volatile organic compounds (VOCs) are usually measure by time-integrative techniques that average peak exposures to insignificance. he specific method involves a preprogrammed sequential syringe sampler that can fill 150-cm3 syringes with air at rates of 2 to 90 min per syringe. he 12 collected samples are then transported to the laboratory for fully automated gas-chromatographic separation with mass spectrometric detection. he instrumentation and method are described, and representative results are given to document the variability in V0C concentrations in situations such as use of household products and water outgassing in residential air, automobiles during driving, and office indoor air that is subject to ventilation system cycling. he method is shown to perform automatically in both sampling and analytical modes. ontamination and sample integrity tests show typical precision to be about 10% relative standard deviation. ield tests show that VOC concentrations can vary by greater than an order of magnitude on different time scales.