Screening methods for the identification of organic emissions from indoor air pollution sources

Abstract

Development of on-line gas Chromatographic screening procedures is necessary to permit subsequent evaluation of materials in test chamber studies. This screening uses techniques such as static vapor-phase sampling by ‘headspace’ methods, and a dynamic method similar to the ‘purge-and-trap’ procedures used for determination of volatile organic compounds in water samples. These are methods of sampling that simulate the chamber conditions on a small scale, while allowing emissions to be collected and analyzed. The evaluation is done to select gas Chromatographic columns and develop operating conditions that will permit the rapid and reliable separation of chemical compounds generated during testing. The Chromatographic procedure is used in the qualitative identification of chemical compounds by gas chromatography/mass spectrometry. After identification of the compounds or, alternatively, their chemical classes, representative members are selected as calibration standards for the actual emission testing program. The standards selected are adequate to allow, in most cases, either quantitative or semi-quantitative calculation of the amount of each material present in the chamber exhaust gas. The use of response curves for the chemical classes allows subsequent recalculation of the amounts for each compound.