Microbial volatile organic compounds in full scale stud cavities: Identification and transport analysis.

摘要

An experimental project is carried out, as a part of the Collaborative Research and Development (CRD) project, to investigate the capacity of wall cavities to contain mold products, emanating from studs with 10% of their surfaces covered with mold, and to constrain their penetration into the indoor space. 20 full-scale stud cavities were constructed to incorporate six experimental parameters related to the design of air leakage path (direct and long), mold contamination, wall construction configurations (vapour barrier, insulation and sheathing material) and ambient conditions (wet and dry conditions). Twelve specimens incorporate wood studs that were inoculated with three predetermined mold species and prepared for about 3 weeks in a mycological lab until 10% of mold coverage was reached. A stainless steel sampling chamber over drywall induced prescribed air infiltration. The tests were designed primarily to study the movement of spores. The project was subsequently extended to investigate the identification of microbial volatile organic compounds (MVOCs) and their transport through the building envelope. This thesis reports the identification of mold related VOCs, the analysis of transport of these MVOCs from the stud cavity to the indoor space and the assessment of the influence of the parameters on this transport. The chemical analysis of the VOCs (volatile organic compounds) samplers and the identification of the chemical components were performed using gas chromatography/mass spectrometry. The identified compounds include VOCs that are commonly found in the indoor air (e.g. Benzene, Toluene, Xylenes, etc.) as well as frequently reported MVOCs (e.g. Furan 3-Methyl). The results were analyzed using multiple regression analysis to identify the mold related VOCs, and to determine the transport through the building envelope. Five VOCs (1-propanol, cyclohexanone, furan 3-methyl, alpha pinene and pentadecane) were identified as significantly related to the presence of mold in the stud cavity, at 5% level of significance. The transport of these MVOCs from the sampling chamber to the cavity was confirmed, however, no significant effect of the parameters related to wall construction configuration were detected.