Volatile organic compounds in ambient air are usually estimated by trapping them from air or collecting whole air samples and returning them to a laboratory for analysis by gas chromatography using selective detection. Immediate data can be obtained, and sampling errors minimized, by analyzing with a field-deployable instrument at the time samples are collected. Portable gas chromatographs are available, but they don't fully meet the need for quick, high-quality data under field conditions. Shortcomings include insensitive detectors, non-selective detectors, poor resolution, retention time drift, maladroit data processing schemes, excessive energy consumption, and vulnerability to weather. Improved waterproofing, temperature regulation, and energy efficiency are particularly crucial to true field-deployability. Mass spectrometric detection, high-speed chromatography, polycapillary chromatography, and peak modulation may lead to useful enhancements in future.