Development of a novel methodology for indoor emission source identification

Abstract

The objective of this study was to develop and evaluate a methodology to identify individual sources of emissions based on the measurements of mixed air samples and the emission signatures of individual materials previously determined by Proton Transfer Reaction-Mass Spectrometry (PTR-MS), an on-line analytical device. The methodology based on signal processing principles was developed by employing the method of multiple regression least squares (MRLS) and a normalization technique. Samples of nine typical building materials were tested individually and in combination, including carpet, ceiling material, gypsum board, linoleum, two paints, polyolefine, PVC and wood. Volatile Organic Compound (VOC) emissions from each material were measured in a 50-liter small-scale chamber. Chamber air was sampled by PTR-MS to establish a database of emission signatures unique to each individual material. The same task was performed to measure combined emissions from material mixtures for the application and validation of the developed signal separation method. Results showed that the proposed method could identify the individual sources under laboratory conditions with two, three, five and seven materials present. Further experiments and investigation are needed for cases where the relative emission rates among different compounds may change over a long-term period. ► Unique emission patterns appear to exist for building materials. ► These unique patterns can be established as emission signatures by PTR-MS. ► VOC mixture emissions among material mixtures appear to be superposed. ► Sorptive effects exist, but can be accurately assessed with the new technique. ► By these identified features, material emission sources can be clearly pointed out.