One of MSI's areas of specialty is the design and execution of measurement programs which employ innovative, open-path spectroscopic analysis techniques for the detection of hazardous air pollutants (HAP) and other gaseous compounds in the ambient air. Application of optical remote sensing (ORS) technologies can provide substantial value-added engineering in many instances.
There are many applications for which ORS-based technologies offer the only viable monitoring method. Open-path Fourier-transform infrared (FTIR) spectroscopy is the most versatile ORS technology, but open-path ultraviolet (UV) and tunable diode laser (TDL) spectroscopy represent the ORS technology of choice for certain classes of compounds and applications.
Regardless of which particular technology is employed, optical remote sensing, when coupled with appropriate on-site meteorological data, can generate accurate emission-rate estimates for many toxic compounds. These emission rates can then be used as input information to dispersion models to predict downwind air quality impacts in near-real-time (on the order of seconds).
The ability to provide accurate emission-rate estimates and offsite
impact assessments make the technology ideal for
applications such as:
(Click onto use of open-path FTIR spectroscopy during site remediations for a detailed discussion of this application.)
(Click onto site-specific vertical dispersion coefficient development for a detailed discussion of how open-path FTIR spectroscopy has been used in this capacity to support emission-rate development for hydrogen sulfide at municipal wastewater treatment plants.)
Concerning the site remediation application, it has been our experience that the "high-tech" nature of the ORS technology invariably leads to community appeal and positive public perception. Total fenceline coverage (the "eye which never sleeps") allays public fear. Such community appeal, in turn, benefits regulatory agencies, as there is less public opposition to the selected clean-up remedy. Systems can be configured for automated operation and off-site data transmittal to facilitate decision-making.
Because information is obtained along an entire pathlength instead of at a single point in space, data representativeness and comparability are unequalled when compared to point monitoring. This also means that small, discrete plumes which might otherwise pass between two point monitors are not missed.
An infinite "sample holding" time exists, as analysis information is stored as an electronic document. This means that the ORS data can be reexamined at a later date for evidentiary reasons, or even reanalyzed should an additional target contaminant be later identified. Any sample collection error is eliminated, as there is no "sample" per se; the media is unaffected by measurement method.
Finally, no calibration is required, as the instrument is intrinsically calibrated. Only daily precision and accuracy assessments need to be made.
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Timothy Minnich and Robert Scotto are recognized experts in the application of ORS technologies to a wide range of air-related problems. They have authored or coauthored numerous publications (click onto resumes for publications listings) on topics such as: interpretation of open-path measurement data; quality assurance issues associated with the collection of open-path FTIR spectroscopic data; the application of ORS technologies in determining emission rates from a variety of industrial and ground-level sources; and the role of meteorology in the application of open-path data.
Timothy Minnich was former Chairman of the Air & Waste Management Association (A&WMA) EO-3 Committee, Air Quality and Atmospheric Studies. The purpose of this Committee is to promote the application of appropriate dispersion meteorology principles, methods, and models to the collection, analysis, and interpretation of open-path ORS data. He served as an instructor for two A&WMA ORS courses (1993-96), and was lead author for preparation of USEPA's draft document, "Field Standard Operating Procedure for Use of Open-Path FTIR Spectroscopy at Hazardous Waste Sites." He also conceptualized and directed development of SPECTRAMET-1, a commercially available air dispersion model software package to predict downwind pollutant concentrations in the field based on ORS measurements and on-site meteorological data.
The following table presents a summary of ORS projects designed and managed by MSI for regulatory application.
Client: Jersey Central Power & Light Co.
An R&D project was carried out to develop a combination IR- and UV-based emissions monitoring technique to measure gaseous pollutants (NOx, VOCs, SO2, and CO) from JCP&L's high-temperature combustion turbines. Developed to meet JCP&L's RACT (reasonably available control technology) compliance and enhanced monitoring needs, this approach was approved by the New Jersey Department of Environmental Protection (NJDEP) and was included as part of JCP&L's RACT compliance plan for NOx and VOCs (volatile organic compounds), as these turbines are located within a severe ozone nonattainment area.
Client: Roy F. Weston, Inc.
An ORS-based air monitoring program was performed in support of an 11-month emergency removal action at the Michigan Avenue Dump Site near Detroit, Michigan. Open-path FTIR spectroscopy was used for two purposes: (1) to ensure that VOC emissions generated during the excavation and off-site transport of waste materials did not exceed health-based property-line exposure levels established by USEPA for this site; and (2) to support the application of vapor suppressants whenever exposure levels were approached. This was the first time that any ORS-based monitoring approach was used to drive an emergency removal action.
Client: Sevenson Environmental Services, Inc.
We designed and managed a 3-year program to provide continuous open-path FTIR spectroscopic monitoring during site remediation activities at Lipari Landfill, the nation's No. 1 site on the National Priorities List for cleanup (NPL) in Pitman, New Jersey. Two monitors were used simultaneously to ensure that VOC emissions generated during soil disturbance and temporary stockpiling activities did not exceed health-based exposure levels established by the Agency for Toxic Substances and Disease Registry (ATSDR) and the NJDEP. This project was significant, as it represented the first time ORS-based monitoring was required as part of a U.S. Army Corps of Engineers (USACE) site clean-up specification.
Client: OHM Remediation Services, Inc.
We designed and managed a comprehensive pilot-scale air monitoring program to support a permit-equivalency demonstration in accordance with requirements of the NJDEP. Open-path FTIR spectroscopy was employed, together with Summa canister, Tedlar bag, and PM10 monitoring, to develop maximum potential emission rates during site-disturbance activities associated with the clean-up of sand pits and lagoons contaminated with petroleum hydrocarbons. Emission rates were demonstrated to be below levels of significance for each of a total of 41 target contaminants, and all analyses were performed to the satisfaction of the NJDEP.
Client: City of New York, NYCDEP
A study was conducted to characterize compounds within the hopper room of the newly constructed sludge dewatering building of the Wards Island wastewater treatment plant. Open-path FTIR spectroscopy was used to identify the source of worker headaches and other health concerns.
Client: National Council of the Pulp and Paper Industry for Air
and Stream Improvement (NCASI)
We designed and managed a 3-day open-path FTIR monitoring program to assess chloroform and methanol emission rates from operations typical of primary clarifiers and aeration basins at a paper mill in Augusta, Georgia. The intent of this program was to refine the emissions module of the CHEMDAT-7 Model for regulatory application under Section 112 of the Clean Air Act concerning MACT (maximum available control technology) implementation. Emission rates were back-calculated based on Gaussian dispersion theory using dual, simultaneous tracers to generate site-specific vertical dispersion coefficients.
Client: USEPA - Environmental Response Team
We designed and managed more than 10 separate projects involving FTIR and UV spectroscopy, all administered under contract to Roy F. Weston as part of their Response Engineering Analytical Contractor (REAC) services contract. These projects involved: development of emission factors during pilot-scale waste disturbance activities; model validation and site-specific vertical dispersion coefficient development downwind of hazardous waste sites; and emissions monitoring during full-scale hazardous waste site remediation activities to protect off-site residents. Also administered under this contract was development of the draft guidance document, "Field Standard Operating Procedure for Use of Open-Path FTIR Spectroscopy at Hazardous Waste Sites." This document remains the most comprehensive guidance developed to date for the application of optical remote sensing to Superfund needs.
Client: Confidential Chemical Manufacturing Facility
A 6-week, 24-hour-per-day program was carried out in which open-path FTIR spectroscopy was employed to determine whether worker health complaints were the result of a documented release of an EHS (extremely hazardous substance). A total of 11 target compounds were identified, and 17 others were added upon spectroscopic review of the initial monitoring results. Instrument operators worked closely with facility engineers to create several PC-based software reports which provided graphical and tabular displays of compound concentrations and action levels as functions of time and meteorology.
Client: Baker & Botts, Inc.
We designed and managed a dispersion model validation study for a confidential client of the law firm of Baker & Botts in support of a class-action suit involving a Houston-based industrial facility. Open-path FTIR spectroscopy was employed over a 2-day period in multiple downwind configurations while a tracer gas was released inside the facility, under controlled conditions, to simulate normal facility operations. The ISCST Model was then configured to predict the path-integrated tracer concentrations along the FTIR pathlengths under a range of observed atmospheric transport and dispersion conditions. Results of the validation study conclusively demonstrated model overprediction by as much as several factors.
Client: American Cyanamid Company
An open-path FTIR-based air monitoring program was performed to estimate VOC emissions from a wastewater lagoon at Cyanamid's Bound Brook, New Jersey facility. This work was part of a comprehensive 10-source evaluation of contaminant migration via the air pathway for a baseline endangerment assessment in support of a site-wide cleanup.
Client: U.S. Army Chemical Biological Defense Command
We designed and managed a comprehensive engineering feasibility assessment concerning the installation of open-path FTIR monitoring equipment to monitor for release of nerve agents stored at three sites at Aberdeen Proving Ground (APG) in Maryland. Two sites were assessed for permanent installations, and the third site, which included buried ordnance, was assessed for FTIR operation during its remediation. The engineering assessment considered issues such as extended operations, maintenance costs and labor, monitoring configurations, and housing design.
Client: Caldwell Trucking Company Responsible Party Group
A complex air characterization assessment was performed in support of the remediation of the Caldwell Trucking Site in Fairfield, New Jersey. This was a two-phased program involving use of open-path FTIR spectroscopy. The first phase, conducted during pilot-scale remediation activities, involved development of emission factors to address NJDEP permit equivalency requirements and to demonstrate that ARARs would not be compromised during full-scale remediation. The second phase involved monitoring during actual cleanup to support protection of off-site residents and to support the application of vapor suppressants whenever off-site exposure levels were approached.
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