Comparative testing of an FTIR remote optical sensor with area samplers in a controlled ventilation chamber

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.