Optical Remote Measurement of Toxic Gases

Grant, William B.; Kagann, Robert H.; McClenny, William A.

doi:10.1080/10473289.1992.10466965

Cited by 91 publications

(24 citation statements)

References 89 publications

(36 reference statements)

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“…However, when only a few gas species are of interest, it may be more beneficial to use other PI-ORS instrumentation, such as the TDLAS or PI-DIAL. 3,15 For landfills, a scanning TDLAS system (hardware and software) was developed to identify hot spots of methane emissions.…”

Section: Technical Papermentioning

confidence: 99%

“…[1][2][3] The radial plume mapping (RPM)-based methodologies use a single ORS monitor to collect path-integrated concentration (PIC) data from multiple beam paths in a plane and combine these with optimization algorithms to map the field of concentration across the plume of contaminant. 4 -14 Horizontal RPM (HRPM) methodology, which is the subject of this paper, was designed to map pollutant concentrations in a horizontal plane.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical Evaluation of a Method for Locating Gaseous Emission Hot Spots

Hashmonay

2008

Journal of the Air & Waste Management Association

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This paper describes and theoretically evaluates a recently developed method that provides a unique methodology for mapping gaseous emissions from non-point pollutant sources. The horizontal radial plume mapping (HRPM) methodology uses an open-path, path-integrated optical remote sensing (PI-ORS) system in a horizontal plane to directly identify emission hot spots. The radial plume mapping methodology has been well developed, evaluated, and demonstrated. In this paper, the theoretical basis of the HRPM method is explained in the context of the method's reliability and robustness to reconstruct spatially resolved plume maps. Calculation of the condition number of the inversion's kernel matrix showed that this method has minimal error magnification (EM) when the beam geometry is optimized. Minimizing the condition number provides a tool for such optimization of the beam geometry because it indicates minimized EM. Using methane concentration data collected from a landfill with a tunable diode laser absorption spectroscopy (TDLAS) system, it is demonstrated that EM is minimal because the averaged plume map of many reconstructed plume maps is very similar to a plume map generated by the averaged concentration data. It is also shown in the analysis of this dataset that the reconstructions of plume maps are unique for the optimized HRPM beam geometry and independent of the actual algorithm applied.

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Section: Technical Papermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Theoretical Evaluation of a Method for Locating Gaseous Emission Hot Spots

Hashmonay

2008

Journal of the Air & Waste Management Association

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“…The OP-FTIR can identify and quantify multiple air pollutants and provide real-time information in situ. 4 When scanning two-dimensionally across the monitoring areas, OP-FTIR covers a much larger area than the point samplers to obtain spatially representative data. The hot spots or high concentration regions could further be identified by reconstructing concentration maps from the OP-FTIR's path-integrated concentration (PIC) data with computed tomography (e.g., refs 5 and 6), or radial plume mapping techniques (e.g., refs 7 and 8).…”

Section: Introductionmentioning

confidence: 99%

Developing and Evaluating Techniques for Localizing Pollutant Emission Sources with Open-Path Fourier Transform Infrared Measurements and Wind Data

Chen

Chang

et al. 2008

Journal of the Air & Waste Management Association

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This paper presents the simulation and field evaluation results of two approaches to localize pollutant emission sources with open-path Fourier transform infrared (OP-FTIR) spectroscopy. The first approach combined the plume's peak location information reconstructed from the Smooth Basis Function Minimization (SBFM) algorithm and the wind direction data to calculate source projection lines. In the second approach, the plume's peak location was determined with the Monte Carlo methodology by randomly sampling within the beam segment having the largest path-integrated concentration. We first conducted a series of simulation studies to investigate the sensitivity of using different basis functions in the SBFM algorithm. It was found that fitting with the beta and Weibull basis functions generally gave better estimates of the peak locations than with the normal basis function when the plumes were mainly within the OP-FTIR's monitoring line. However, for plumes that were symmetric to the peak position or spread over the OP-FTIR, fitting with the normal basis function gave better performance. In the field experiment, two tracer gases were released simultaneously from two locations and the OP-FTIR collected data downwind from the sources with a maximum beam path length of 97 m. For the first approach, the release locations were within the 0.25-to 0.5-probability area only after the uncertainty of the peak locations was included in the calculation process. The second approach was easy to implement and still performed as satisfactorily as the first approach. The distances from the sources to the best-fit lines (i.e., the regression lines) of the estimated locations were smaller than 10 m. INTRODUCTIONLocalizing (i.e., locating) toxic air pollutant sources is an important issue in many environment and health-related fields. To minimize the air pollutants' impact on the environment and the public health, it is necessary to identify the releasing sources in a timely fashion so that an effective control strategy can be implemented. For example, in homeland security applications, the release locations of harmful airborne contaminants usually are unknown. Their locations must be estimated from the postrelease concentration observations. 1 Another example is the leak detection of volatile organic compounds (VOCs) from the refinery or petrochemical industries. Detecting the source of a leak from thousands of possible components is always a challenging task; nevertheless, fixing the identified leaking components not only protects public health and the environment but also reduces waste and any potential liability.For a large area, one way to locate the fugitive emission source(s) of hazardous chemicals is placing a matrix of point samplers at the monitoring site. In Chen et al., 2,3 3-hr canister samples were taken from 25 sites inside a petrochemical plant, twice per season for 1 yr. These samples were then analyzed with gas chromatography/ mass spectrometry (GC/MS) according to the U.S. Environmental Protection Agency (E...

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“…These sensors have been used to characterize emissions from area sources such as hazardous waste sites. 11 A major disadvantage of remote sensing is the high cost of instrumentation and personnel training. In addition, atmospheric trace gases such as water vapor, carbon dioxide, and ozone can interfere with measurements of the target gas.…”

Section: Introductionmentioning

confidence: 99%

Near Surface Soil Vapor Clusters for Monitoring Emissions of Volatile Organic Compounds from Soils

Ergas

Hinlein

Reyes

et al. 2000

Journal of the Air & Waste Management Association

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The overall objective of this research was to develop and test a method of determining emission rates of volatile organic compounds (VOCs) and other gases from soil surfaces. Soil vapor clusters (SVCs) were designed as a low dead volume, robust sampling system to obtain vertically resolved profiles of soil gas contaminant concentrations in the near surface zone. The concentration profiles, when combined with a mathematical model of porous media mass transport, were used to calculate the contaminant flux from the soil surface. Initial experiments were conducted using a mesoscale soil remediation system under a range of experimental conditions. Helium was used as a tracer and trichloroethene was used as a model VOC. Flux estimations using the SVCs were within 25% of independent surface flux estimates and were comparable to measurements made using a surface isolation flux chamber (SIFC). In addition, method detection limits for the SVC were an order of magnitude lower than detection limits with the SIFC. Field trials, conducted with the SVCs at a bioventing site, indicated that the SVC method could be easily used in the field to estimate fugitive VOC emission rates. Major advantages of the SVC method were its low detection limits, lack of required auxiliary equipment, and ability to obtain realtime estimates of fugitive VOC emission rates. IMPLICATIONSThis research will aid in achieving both hazardous air pollutant and ozone precursor goals set by the U.S. Environmental Protection Agency and state regulatory agencies by providing an accurate, rugged, and easy to use method of monitoring air emissions of volatile organic compounds and other gases from soil surfaces. The method has several advantages over methods of monitoring fugitive emissions from soil surfaces, including faster sampling time, lower detection limits, and the ability to obtain real-time results without cryogenic or sorbent tube trapping.

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Optical Remote Measurement of Toxic Gases

Cited by 91 publications

References 89 publications

Theoretical Evaluation of a Method for Locating Gaseous Emission Hot Spots

Theoretical Evaluation of a Method for Locating Gaseous Emission Hot Spots

Developing and Evaluating Techniques for Localizing Pollutant Emission Sources with Open-Path Fourier Transform Infrared Measurements and Wind Data

Near Surface Soil Vapor Clusters for Monitoring Emissions of Volatile Organic Compounds from Soils

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