"Measurement of Indoor-Outdoor and Inter-Room Air Exchange Rates and Concentrations of VOCs and Carbonyl Compounds for Risk Assessment" 

Naohide Shinohara¹, Toshiyuki Kataoka², KouichiTakamine², Toshiyoshi Nakamura², Katunori Motohashi², Kazuhiro Nisijima³, Michio Butsugan⁴, Gamo Masashi ¹

¹National Institute of Advanced Industrial Science and Technology
²Chemicals Evaluation and Research Institute,Japan
³Sigma-Aldrich Corporation
⁴Hitachi Chemical Co., Ltd.

 International Conference on Environmental Epidemiology & Exposure - joint ISEE/ISEA Conference 2006 (Paris (France) 2006/9/3)

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Abstract

Methods
PFT method was applied for the measurement of 24-hours mean air exchange rates. p- fluorocarbon (PFCs) and 39 VOCs sampled by a single charcoal tube were extracted in solvent and analyzed by a GC-MS. The tracers tested in this study were p-methylcyclohexane (PMCH), p-dimethylcyclohexane (PDCH), hexafluorobenzene (HxFBz), octafluorotoluene (OFT) and perfluoroallylbenzene (PFABz). Regarding the extraction solvent, carbon disulfide (CS2), hexane and dichloromethane were tested. We developed an inexpensive and easy-to-use tracer source. The emission rates of these tracers from a developed source were gravimetrically measured in a test chamber. This method was applied to measure the variability of yearly average air exchange rates and indoor concentrations of VOCs and carbonyl compounds. In three rooms and outdoor of 26 houses, 24-hours average concentrations of VOCs and four carbonyl compounds and air exchange rates were simultaneously measured everyday for a week in four seasons each (Summer, 2005 – Spring, 2006). 
Results
Selected tracer gases were HxFBz, OFT and PFABz and CS2 was selected as an extraction solvent. Recovery rates of HxFBz, OFT and PFABz exracted by CS2 were 40% ± 3%, 72% ± 5%, 84% ± 6%. Recovery rates of VOCs were approximately more than 90% by CS2. The emission rates of tracers from the developed sources were confirmed to be very stable. Temperature correction is, however, needed in the field measurement since it was found the emission rates depend on temperature. The air exchange rates measured by PFT were close to that measured by CO2 constant emission method.

Keywords

Air Exchange Rates, PFT, VOCs, Carbonyl compounds, Uncertainty