Infrared remote sensing and determination of pollutants in gas plumes

Prengle, H. W.; III, Charles A. Morgan; Fang, C. S.; Huang, Ling-Kun.; Campani, Paolo.; Wu, Wei

doi:10.1021/es60077a007

Cited by 22 publications

(10 citation statements)

References 13 publications

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“…Perhaps the most common monitoring technique is provided by Fouriertransform spectrometers (FTS), and their use for environmental monitoring is well documented. [1][2][3][4][5][6] This is no surprise as their ability to measure spectral emissions across a wide spectral band at arbitrary (in principle) spectral resolution with excellent efficiency makes them well suited to the species identification and quantification problem. FTS-based ultraspectral imagers have recently become commercially available and could significantly improve the accuracy of species quantification.…”

Section: Introductionmentioning

confidence: 99%

Instrument calibration and lineshape modeling for ultraspectral imagery measurements of industrial smokestack emissions

Gross¹,

Tremblay

Bradley³

et al. 2010

SPIE Proceedings

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The Telops Hyper-Cam midwave (InSb 1.5-5.5 μm) imaging Fourier-transform spectrometer observed the plume from a coal-burning power plant smokestack. From a distance of 600 meters, the plume was captured on a 128 × 64 pixel sub-window of the focal-plane array with each pixel imaging a 19.5 × 19.5 cm 2 region. Asymmetric interferograms were collected with long side and short side maximal optical path differences of 2.4 cm and 0.9 cm, respectively. Interferograms were recorded for each scan direction. The plume was strongly emissive across 1800-3000 cm −1 , and raw spectra revealed emissions from CO 2 , CO, H 2 O, NO, SO 2 , and HCl. A complete description of the instrument calibration and lineshape modeling is presented, including a simple and computationally efficient method of averaging spectra from forwardand reverse-scan interferograms that avoids the need to model a complex instrument lineshape. A simple radiative transfer model is developed to interpret the spectrum between 2565 ≤ν ≤ 3000 cm −1 . Examination of the HCl spectrum demonstrates exceptional agreement between the data and an ideal instrument lineshape. For a pixel immediately above the stack exit, the plume temperature is estimated to be 399.6 ± 0.6 K with an SO 2 concentration of 376 ± 10 ppm v , and these values agree well with in situ measurements of 407.0 ± 0.2 K and 383 ± 2 ppm v , respectively.

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Section: Introductionmentioning

confidence: 99%

Instrument calibration and lineshape modeling for ultraspectral imagery measurements of industrial smokestack emissions

Gross¹,

Tremblay

Bradley³

et al. 2010

SPIE Proceedings

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“…This procedure is a correction for the intrinsic strengths of the molecular transitions, which will generally differ from the blackbody curve. If the ratio is known at some particular temperature, Equation (7) or Equation (8) can be used to predict the ratio at other temperatures. Comparison with the measured ratio provides the temperature diagnostic.…”

Section: Discussionmentioning

confidence: 99%

Theory, modeling, and measurements of gas plumes

2003

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Spectroscopic measurements of infrared CO2 transitions in gas plumes are reported, and evaluated for their potential to yield a reliable remote sensing technique for determination of plume temperature. Measurements were made on two types of plumes: a sideways-directed plume from a vehicle exhaust, and a stack plume from a propane-burning portable plume generator. Modeling of CO2 emission near 4.25 tm from the portable plume generator does not yield a temperature diagnostic due to heavy and unpredictable atmospheric absorption. The 4.25 jim band is optically thick in the vehicle exhaust plume measurements. For the vehicle plume, the blackbody Planck equation is used to derive temperatures that agree with results of thermocouple measurements. The ratio of optically thin signals obtained in the vicinity of the 4.25 im and 14.4 im transitions is related to temperature in accordance with Boltzmann statistics. For these experimental conditions, the ratio calculated from the Boltzmann distribution has similar temperature dependence to the ratio obtained from the blackbody Planck equation. Because the ratio of signals obtained at two optically thin wavelengths is independent of concentration, this technique has promise for field measurement of plume temperatures.

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“…Attempts to use OP-FTIR for environmental measurements were made as early as 1967, 1 however it was not until the late 1980s that the method began to gain the interest required for full development of its potential. 2,3,4 The potential of OP-FTIR for stand-off chemical agent detection has compelled the military community to also play a major role in the development of the technology. 5 Many different optical configurations are available to enable an OP-FTIR measurement to achieve an appropriate optical beam path to monitor the compounds of interest.…”

Section: This Issue Of Field Analytical Chemistry and Technologymentioning

confidence: 99%