Gerhard Matz

Scanning infrared remote sensing system for identification, visualization, and quantification of airborne pollutants

Remote sensing by Fourier-transform infrared (FTIR) spectrometry allows detection, identification, and quantification of airborne pollutants. In the case of leaks in pipelines or leaks in chemical plants, chemical accidents, terrorism, or war, hazardous compounds are often released into the atmosphere. Various Fourier-transform infrared spectrometers have been developed for the remote detection and identification of hazardous clouds. However, for the localization of a leak and a complete assessment of the situation in the case of the release of a hazardous cloud, information about the position and the size of a cloud is essential. Therefore, an imaging passive remote sensing system comprised of an interferometer (Bruker OPAG 22), a data acquisition, processing, and control system with a digital signal processor (FTIR DSP), an azimuth-elevation-scanning mirror, a video system with a DSP, and a personal computer has been developed. The FTIR DSP system controls the scanning mirror, collects the interferograms, and performs the Fourier transformation. The spectra are transferred to a personal computer and analyzed by a real-time identification algorithm that does not require background spectra for the analysis. The results are visualized by a video image, overlaid by false color images. For each target compound of a spectral library, images of the coefficient of correlation, the signal to noise ratio, the brightness temperature of the background, the difference between the temperature of the ambient air and the brightness temperature of the background, and the noise equivalent column density are produced. The column densities of all directions in which a target compound has been identified may be retrieved by a nonlinear least squares fitting algorithm and an additional false color image is displayed. The system has a high selectivity, low noise equivalent spectral radiance, and it allows identification, visualization, and quantification of pollutant clouds.

Begasungsmittelrückstände und toxische Industriechemikalien in Import-Containern

ZusammenfassungBegasungsmittelrückstände und toxische Industriechemikalien in Import-Containern können für das betroffene Personal gesundheitsgefährdend sein. Um die Gefährdung abschätzen zu können, sollten im Rahmen dieser Studie aus mehr als 2000 Import-Containern Luftproben analysiert werden. Weitere Ziele der Messkampagne waren, Daten für einen Gerätevergleich zu erhalten sowie neuere feldtaugliche Messgeräte im Routinebetrieb zu testen und deren Ergebnisse–soweit möglich–mit etablierten Labor-Techniken (Thermodesorptions-Gaschromatographie-Massenspektrometrie, TD-GC-MS) zu vergleichen.Zum Einsatz kamen ein Gefahrstoff-Detektoren-Array (Handgerät, GDA II, Airsense), ein Selected Ion Flow Tube-Massenspektrometrer (Standgerät, SIFT-MS, Voice 100, Syft Technologies), ein mobiles TD-GC-MS (EM 640S Bruker Daltoniks) und ein Labor-TD-GC-MS (Agilent G530N-MS5973N) sowie Kurzzeit-Prüfröhrchen (Begasungs-Test-Set, Dräger). Je nach Herkunftsland fanden sich in bis zu ca. 50% der Container toxische gasförmige Inhaltstoffe, überwiegend in niedriger Konzentration. In 17,4% (367 Container) der 2111 untersuchten Container, die alle nicht als begaste Einheit oder sonstiges Gefahrgut gekennzeichnet waren, wurden Grenzwertüberschreitungen festgestellt: Phosphorwasserstoff (27), Brommethan (8), 1,2-Dichlorethan (12), Trichlornitromethan (Chlorpikrin) (27), Formaldehyd (218), Benzol (130). Die Grenzwerte folgender toxisch wirkender Stoffe wurden um mehr als das Zehnfache überschritten: Brommethan (1), Trichlornitromethan (13), Phosphorwasserstoff (14), 1,2-Dichlorethan (5).Das GDA II erwies sich als breitbandig messendes Warngerät zur Detektion, bisher aber nicht zur Identifikation einzelner Begasungsmittel geeignet. Es lieferte für die meisten Begasungsmittel (außer z.B. Formaldehyd) ein Warnsignal innerhalb 10 Sekunden. Das SIFT-MS konnte im Prinzip fast alle Gase schnell identifizieren, zeigte jedoch häufig falsch positive Ergebnisse an (Signal, obwohl keine Substanz vorhanden) für Ethylenoxid, Formaldehyd, Phosphorwasserstoff, Sulfuryldifluorid und 1,2-Dichlorethan. Falsch negative Befunde (Substanz vorhanden und kein Signal) traten in den Messungen mit dem SIFT-MS und dem GDA II nur in geringem Umfang und jeweils nur im Bereich niedriger Konzentrationen auf. Die falsch negativen und falsch positiven Ergebnisse wurden mit Hilfe der TD-GC-MS-Analysen bestimmt (Ausnahmen: Cyanwasserstoff, Phosphorwasserstoff, Ethylenoxid, Formaldehyd). Die Ergebnisse, die mit Kurzzeitprüfröhrchen (Dräger) erhalten wurden, waren verhältnismäßig häufig falsch positiv oder falsch negativ. Die Ergebnisse zeigen, dass die Feldgeräte im Prinzip geeignet sind, schnell eine Gefährdung anzuzeigen und damit Sicherheitsmassnahmen einzuleiten. Es besteht jedoch Optimierungsbedarf bezüglich der falsch positiven Resultate, die u.a. unter wirtschaftlichen Aspekten (unnötige Belüftungen und Freimessungen) reduziert werden müssen.Die Studie ergab, dass unter dem Aspekt des Gesundheitsschutzes die Überwachungs- und Präventionsmaßnahmen über Begasungsmittel hinaus auf weitere toxische und/oder kanzerogene Stoffe auszudehnen sind. Das gilt besonders für Schuh- und Textilimporte aus Südostasien. Unter Präventionsaspekten dürfen derartige Risiko-Container, v.a. wenn Lüftungsschlitze verklebt sind, erst nach Ausschluss toxischer Schadstoffbelastungen mittels geeigneter Messgeräte, ggf. nach ausreichender Belüftung und Freimessung betreten werden.SummaryResidues of fumigation agents and toxic industrial chemicals in import containers can be harmful to the health of workers affected. In order to be able to assess the danger, this study was to analyse air samples from the largest and most representative number of over 2,000 import containers. Further objectives of the 9-week study were to obtain data for an equipment comparison, and to test new field measuring devices in routine operation, and wherever possible to compare their results with established laboratory techniques (thermo-desorption gas chromatography mass spectrometry, TD-GC-MS). The equipment used included a hazardous materials detector array (hand-held unit, GDA II, Airsense), a selected ion flow tube mass spectrometer (stand device, SIFTMS, Voice 100, Syft Technologies), a mobile TD-GC-MS (EM 640S Bruker Daltoniks) and a laboratory TD-GC-MS (Agilent G530N-MS5973N) together with shortterm test tubes (Dräger Fumigation Test Set). Depending on the country of origin, up to approx. 50% of the containers were found to contain toxic gaseous materials, predominantly in low concentrations. The exceeding of limit values was established in 17.4% (367 Container) of the 2,111 import containers examined, none of which were marked as fumigated units or containing other hazardous materials: Hydrogen phosphide (27), bromide-methane (8), 1,2-dichlorethane (12), trichloro-nitromethane (Chloro-picrin) (27), formaldehyde (218), benzol (130). The limit value of the following toxic materials was exceeded by a factor of over 10: Bromide-methane (1), trichloro-nitromethane (13), hydrogen phosphide (14), 1,2-dichlorethane (5).The GDA II proved to be a suitable broad-band measuring warning device for the detection, although not for the identification of individual fumigation agents. For most fumigation agents (except formaldehyde for example), it provided a warning signal within 10 seconds. The SIFT-MS was in principle able to identify almost all gases quickly, although it frequently indicated false positive results (warning signal, even though the substance was not present) for ethylene oxide, formaldehyde, hydrogen phosphide, sulfuryl-difluoride and 1,2-dichlorethane. False negative findings (substance present and no signal) only occurred in a few cases in the measurements with the SIFT-MS and the GDA II, and then only at low concentrations. The false negative and false positive results were identified with the aid of the TD-GC-MS analyses (exceptions: hydrogen cyanide, hydrogen phosphide, ethylene oxide, formaldehyde). The results obtained with the shortterm test tubes (Dräger) relatively frequently gave false positive or false negative indications. The results show that the field equipment is in principle suitable to indicate any danger quickly and institute corresponding safety measures. There is however a need for optimisation regarding the false positive results, which must be reduced, for economic reasons amongst others (unnecessary ventilation and measurements).The study showed that from the aspect of health protection, the monitoring and prevention measures applied to fumigation agents should be extended to other toxic and/or carcinogenic materials. This applies particularly to shoe and textile imports from South-east Asia.From the point of view of prevention aspects, and especially if the ventilation slots are blocked, such risk containers should only be entered after the absence of toxic contamination has been confirmed by suitable measuring equipment, and if necessary after adequate ventilation and further measurements.RésuméLes résidus d’agents de gazage ainsi que des produits chimiques industriels toxiques contenus dans des conteneurs d’importations sont susceptibles de nuire à la santé du personnel concerné. En vu de permettre d’évaluer les risques, le but de la présente étude consistait à analyser des échantillons d’air contenus dans plus de 2000 conteneurs d’importation, donc d’un nombre aussi élevé et représentatif que possible. Par ailleurs, la campagne de prises de mesures sur une période de neuf semaines visait également l’obtention de données pour une comparaison des appareils ainsi que le test d’appareils de mesures récents adaptés à un fonctionnement de routine de grande envergure ainsi que la comparaison des résultats — dans la mesure du possible — avec des techniques établies de laboratoires (spectrométrie de masse par thermodésorption et chromatographie gazeuse, TD-GC-MS). Ont été utilisés une rangée de détecteurs de substances toxiques (appareil portable, GDA II, Airsense), un Selected Ion Flow Tube Mass Spectrometry (appareil isolé, SIFT-MS, Voice 100, Syft Technologies), un TD-GC-MS mobile (EM 640S Bruker Daltoniks) et un TD-GC-MS de laboratoire (Agilent G530N-MS5973N) ainsi qu’un tube de test rapide (Kit de test de gazage, Dräger). Jusqu’à 50 % de conteneurs — ceci en fonction du pays d’origine — présentaient des substances toxiques gazeuses, essentiellement à des faibles concentrations. Des dépassements des valeurs limites ont été détectés chez 17,4 % (367 conteneurs) sur les 2111 conteneurs contrôlés d’importation dont aucun n’avait été marqué comme unité gazé ou autres matière dangereuse : hydrogène phosphoré (27), méthane de bromure (8), 1,2-dichloréthane (12), trichlornitrométhane (chloropicrine) (27), formaldéhyde (218), benzol (130). Les valeurs limites des substances toxiques suivantes ont été dépassées à plus de dix fois : méthane de bromure (1), trichlornitrométhane (13), hydrogène phosphoré (14), 1,2-dichloréthane (5). Le GDA II s’est avéré être un appareil d’avertissement aux mesures à large échelle pour la détection, mais qui, à ce jour, ne convient pas pour l’identification de différents agents de gazage. Il émettait, pour la plupart des agents de gazage (à l’exception p. ex. du formaldéhyde) un signal d’alarme sonore dans les 10 secondes. Le SIFT-MS était, en principe, en mesure d’identifier presque tous les gaz rapidement, mais indiquait souvent de faux résultats positifs (émission d’un signal malgré l’absence de toute substance) pour l’oxyde d’éthylène, le formaldéhyde, l’hydrogène phosphoré, le difluorure sulfuryle et le 1,2-dichloéthane. Les mesures réalisées avec le SIFT-MS et le GDA II présentaient de faux résultats négatifs (absence de signal malgré la présence d’une substance) dans une moindre envergure seulement et ceci uniquement dans une plage de faibles concentrations. Les résultats erronés négatifs et positifs ont été déterminés à l’aide d’analyses TD-GC-MS (exceptions

Infrared remote sensing of hazardous vapours: surveillance of public areas during the FIFA Football World Cup 2006

The German ministry of the interior, represented by the civil defence agency BBK, established analytical task forces for the analysis of released chemicals in the case of fires, chemical accidents, terrorist attacks, or war. One of the first assignments of the task forces was the provision of analytical services during the football world cup 2006. One part of the equipment of these emergency response forces is a remote sensing system that allows identification and visualisation of hazardous clouds from long distances, the scanning infrared gas imaging system SIGIS 2. The system is based on an interferometer with a single detector element in combination with a telescope and a synchronised scanning mirror. The system allows 360° surveillance. The system is equipped with a video camera and the results of the analyses of the spectra are displayed by an overlay of a false colour image on the video image. This allows a simple evaluation of the position and the size of a cloud. The system was deployed for surveillance of stadiums and public viewing areas, where large crowds watched the games. Although no intentional or accidental releases of hazardous gases occurred in the stadiums and in the public viewing areas, the systems identified and located various foreign gases in the air.

Hand‐portable gas‐detector array (GDA) for rapid field detection and identification of chemical threat

In the case of accidents at chemical plants, during transportation of chemicals or during terrorist attacks, hazardous compounds may be released and may harm emergency personnel and population. To prevent this a simple chemical hazard monitor is required to help locate the dangerous area, its border, and the safe area, as recently pointed out by Overton1 in a FACT editorial. Normally, only one or a few compounds are released, but a wide range of compounds has to be considered and must be measurable. In such cases, single-compound detectors may not provide any information or may provide misleading information. Alternative systems that determine sum parameters will give insufficient information to make a decision plan for environmental-protection activities or intervention by firefighters. However, there is always the danger of failing to detect important toxic substances if only one sensing technology is used. In principle, all relevant compounds can be measured at low concentrations by laboratory analysis. However, techniques for task forces in the field are usually limited to simple equipment2,3 and are useful for only a limited range of substances. Making laboratory analytical techniques available to the firefighter is the first successful step in accident analysis. However, devices such as mobile GC/MS and optical systems4,5 need to be operated by specially trained personnel. Furthermore, because of relatively high costs only few special-purpose forces use this equipment. Given the large amount of chemical hazardous compounds produced nowadays and the frequency of accidents reported in the past and anticipated accidents in the future, guidelines with lists of the major fraction of hazardous substances have been established in the United States (Emergency Response Planning Guidelines, ERPG26) and in Germany (Einsatz Toleranz-Werte: ETW, tolerable concentration values7). In addition to the substances in these lists, chemical warfare agents have to be considered, for example, in the case of terrorism. Detecting these substances in the field has been the objective of incident detection and measurement device developments. One result of our development efforts is the portable gas detector array (GDA). Its analytical task, selected sensors, signal interpretation, and measuring strategy as well as first experiences from the fire brigades using the prototype instruments are presented here.

New scanning infrared gas imaging system (SIGIS 2) for emergency response forces

The German ministry of the interior, represented by the civil defense agency BBK, is currently establishing analytical task forces for the analysis of released chemicals in the case of fires or chemical accidents. One part of the equipment of these emergency response forces will be a remote sensing system that allows the identification of hazardous clouds from long distances. Therefore, a new scanning infrared gas imaging system, SIGIS 2, is currently being developed at TUHH. The system is based on an interferometer with a single detector element (Bruker OPAG 33) in combination with a telescope and a synchronized scanning mirror. The new scanning system allows 360° surveillance. For simple interpretation of the results, the system is equipped with a video camera and the results of the analyses of the spectra are displayed by an overlay of a false color image on the video image. This allows a simple evaluation of the position and the size of a cloud. In order to allow simultaneous display of false color representations of measurement results and of the video image in real-time, a new scanner module has been developed. In the standard measurement mode, 16 two-sided interferograms per second are measured, analyzed, and the results are displayed. The spectral resolution is 4 cm-1. The new interferometer, the new scanning system, the data analysis method, and first results of measurements are presented.

Remote detection of methane by infrared spectrometry for airborne pipeline surveillance: first results of ground-based measurements

The total length of natural gas pipelines in Germany exceeds 350,000 km. Currently, inspections are performed using hand-held sensors such as flame ionization detectors. Moreover, transmission pipelines are inspected visually from helicopters. In this work, remote detection of methane by passive Fourier-transform infrared (FTIR) spectrometry for pipeline surveillance is investigated. The study focuses on fast measurements in order to enable methane detection from a helicopter during regular inspection flights. Two remote sensing systems are used for the detection of methane: a scanning infrared gas imaging system (SIGIS), which was originally developed for the visualization of pollutant clouds, and a new compact passive scanning remote sensing system. In order to achieve a high spectral rate, which is required due to the movement of the helicopter, measurements are performed at low spectral resolutions. This results in overlapping signatures of methane and other constituents of the atmosphere in the measured spectrum. The spectra are analyzed by a detection algorithm, which includes simultaneous least squares fitting of reference spectra of methane and other atmospheric species. The results of field measurements show that passive remote sensing by FTIR spectrometry is a feasible method for the remote detection of methane.

Fast detection of preservatives on waste wood with GC/MS, GC-ECD and ion mobility spectrometry

Large amounts of waste wood have to be separated into contaminated material containing wood preservatives and wood ready for reuse, according to the planned German federal legislation for recycling. Therefore three different methods for the detection of wood preservatives on wood waste are presented and compared. A battery-powered ion mobility spectrometry (IMS) device has been equipped with a thermal desorption chamber for the analysis of small pieces of preserved wood samples. The results obtained with this new instrument are compared to those of a mobile GC/MS system and a portable, multicapillary GC-ECD instrument, both equipped with direct thermal desorption injection devices. In this comparison the IMS device emerges favorably. Compound identification by ion mobility spectra, a short analysis time of less than 1 minute without sample treatment, low cost per analysis and good portability of the equipment are the advantages of IMS.

Online Measurement of Polycyclic Aromatic Hydrocarbons by Fast GC/MS

Abstract A novel system, based on gas chromatography mass spectrometry has been developed for the on-line assessment of PAH at combustion processes. The analytical results are obtained on site after minutes. Because of their wide range of volatility, PAHs always occur in a gaseous fraction and a particle adsorbed fraction. A sampling technique for the particulate fraction, based on the dilution method and filter tape sampling, has been constructed. By thermodesorption, fast GC and the combination with a membrane inlet system for the MS an analysis down to the ppb level at a cycle rate of 5 minutes has been achieved. Quick GC runs are possible because of the light weight construction of the chromatographic system. This analytical system has been tested on-site at several emission sources (oil combustion plants, coke oven and diesel engines). Analytical results demonstrate the advantages of this concept. A comparison is done with results from other methods.

SIGIS HR: a system for measurement of aircraft exhaust gas under normal operating conditions of an airport

To gather information about the impact on the environment caused by airport operations, knowledge about the amount of gases such as CO or NOX emitted by aircraft engines on the ground is important. In order to avoid influences on airport operations an analysis system for this application has to enable measurements on the hot jet engine exhaust gas from a distance. The infrared radiation emitted by the hot gas can be analysed by Fourier-transform infrared spectroscopy to determine the composition of the gas. To fulfil this task, a new version of the scanning infrared gas imaging system (SIGIS HR), using relatively high spectral resolution (0.2 cm-1), has been developed. The period of time for measurements on the engine exhaust gas of an aircraft on the ground is short during normal airport operations. Hence the remote sensing system has to be aligned to the exhaust gas plume quickly. For this reason the system is equipped with a scanning mirror actuated by stepper motors in order to allow fast changes of the line of sight. An infrared camera combined with a DSP-system enables automatic alignment of the system to the hot exhaust gas and tracking of a moving engine via online analysis of the infrared image. Additionally fast scans with low spectral resolution of the area around the engine-outlet can be performed. On the basis of the low resolution data the optimal direction for the exhaust gas measurement can be found using several automatic evaluation- and positioning-algorithms. After the SIGIS HR-system has been positioned correctly it is operated in high- resolution-mode in order to quantify the target compounds.

Ölemission eines Ottomotors

Die Messung der Olemissionen, die durch thermische und gasdynamische Prozesse eines Verbrennungsmotors entstehen, und die anschliesende Validierung eines Simulationsprogramms war Ziel der FVV-Forschungsvorhaben „Olverdampfung“ I bis III (FVV-Nr. 902). Dafur wurde von Helmut-Schmidt-Universitat (Universitat der Bundeswehr Hamburg), Technischer Universitat Hamburg-Harburg und Universitat Kassel erstmalig eine Zylinder-Gasentnahme und ein schnelles Massenspektrometer-Messverfahren entwickelt, mit dem die dampfformigen Olbestandteile im Zylinder eines Ottomotors erfasst werden. Durch die Messungen konnte die Simulation der Kolbenring-Zylinder-Olemissionen in diesen Forschungsvorhaben entscheidend weiterentwickelt werden.