Comparison study on portable wind tunnel system and isolation chamber for determination of VOCs from areal sources

Abstract

Many environmental monitoring programmes require the determination of volatile organic compounds (VOCs) emitted from large areal sources including liquid surfaces. A study was carried out to compare existing sampling techniques. Both the isolation chamber method (static technique) and the wind tunnel method (dynamic technique) were examined. A review of the mechanisms suggested that static techniques would not be appropriate for determining emissions from liquid surfaces which result from gas phase controlled volatilisation processes. A portable wind tunnel developed at the University of New South Wales and an isolation chamber built to USEPA specification were used in an experimental study of emissions from aqueous liquid surfaces. An acetone solution was chosen to represent gas phase controlled volatilisation processes. Toluene and methyl ethyl ketone in aqueous solution were chosen, respectively to investigate (1) liquid phase controlled volatilisation processes, and (2) combined gas and liquid phase controlled volatilisation processes. It was found that the use of the isolation chamber method resulted in different degrees of underestimation of the emission rates for the above three compounds. The wind tunnel method is suitable for sampling all VOC emissions from areal sources.

Odor Emission Rate Estimation of Indoor Industrial Sources Using a Modified Inverse Modeling Method

“…11 The system is operated with carbon-activated filtered air that is supplied at a controlled rate by a blower. 24 Results from a wind tunnel system are repeatable during the sampling process. 12 Wind tunnels simulate an ideal condition of uniform horizontal airstream over the measurement section.…”

“…Under the same wind conditions, the smaller wind tunnel exhibits higher emission rates. 25 The University of New South Wales wind tunnel by Jiang et al 24 was used to measure emission rates of volatile organic compounds released from large area sources. Jiang and associates determined the appropriate velocity on the basis of wind speeds associated with the most odor complaints.…”

Developing Odor Impact Assessment Procedures

“…The inherent design and performance characteristics of static isolation flux chambers in comparison with portable wind tunnels for measuring odor emission rates have been discussed in detail (Environmental Odour Laboratory, 1999). Furthermore, the designs and comparative performances of static isolation flux chambers and portable wind tunnels for measuring volatile chemical compounds have also been discussed in detail (Jiang and Kaye, 1996).…”

Estimation of odor emission rate from landfill areas using the sniffing team method

“…A first way to estimate the overall odor emission rate from a diffuse source, like the fresh deposits of municipal waste, is to use an isolation flux chamber (Reinhart et al, 1992) or a portable wind tunnel (Jiang and Kaye, 1996) placed on the landfill surface to collect gases, which are then transferred to a Tedlar ® bag for subsequent testing by olfactometry. Dynamic olfactometry (e.g.…”