A portable Fourier transform infrared remote optical sensing spectrometer
was deployed and tested in a constant ventilation test chamber
by using a tracer gas source. Continuous beam path measurements
were collected and compared to air samples obtained from a computer-controlled,
multiple-point sampling array connected to a flame ionization
detector. Measurements were gathered at two different room ventilation
rates and at two different dispersion conditions. A homogeneous
dispersion condition had a uniform tracer concentration over the
beam path and an inhomogeneous dispersion condition had a nonuniform
tracer concentration distribution over the length of the beam
path. Overall, the beam measurements and the point sample readings
showed good agreement regardless of the room ventilation rate.
Comparative data obtained from the inhomogeneous dispersion conditions
did have higher variability, probably as a result of the different
spatial and temporal resolution of the two sampling techniques.
The tests demonstrate that a remote sensing system can be applied
to an indoor room scale setting, but the dispersion of contaminant
in the beam path is an important factor to consider when interpreting
the beam data.
