An aspiration-type Ion Mobility Spectrometer (IMS) was connected to an in-house developed Pulsed Sampling System (PSS) through a heated capillary column acting as transfer line, after being modified to a closed loop IMS device. Performance of the whole system was evaluated using acetone gas standards in the concentration range of 200-2000 ppb. Tests were carried out using an in-house developed chemical environment generator for producing acetone concentrations. The system presented long-term stability, linearity, sensitivity and low minimum detectable level; less than 286 ppb for acetone with a closed loop that circulates 1300 mL/min of purified air. Repeatability (RSD) was less than 15% for all concentrations. All data were produced in dry atmosphere inside the IMS; presence of moisture (e.g. when saturation of molecular sieves occurs) seems to severely reduce performance. (C) 2015 Elsevier B.V. All rights reserved.

Search and Rescue (SaR) in forest fires is usually applied in a broad area, under foggy or smoky conditions. It mostly involves location of entrapped fire crew or people in between fire fronts, as well as, safely removing them away from the dangerous zone. Moreover, SaR is applied in evacuation of rural residential areas due to heavy smoke impacts, or fire front approaching. Experiences achieved during a field trial, in which unmanned aerial and ground vehicles were deployed and used in a simulated forest fire SaR scenario, are presented. For planning and running the field trial a number of parameters were taken into consideration; logistics, safety plan, contingency plan, different agencies cooperation, time frames and ethical issues. Advantages of using unmanned aerial and ground vehicles in SaR operations include capability of planning and monitoring the operations, integration with the manned resources, connectivity with command and control centers, as well as, coordination of the different unmanned aerial and ground vehicles' platforms. Significant increase of personnel safety is possible through the capabilities of air quality monitoring and search over dangerous areas. Current limitations include limited heat resistance of vehicles and limited flying capability in strong winds and turbulence. Failure of communications is also possible due to rough terrain (autonomy limitations). Against all the limitations, a number of unmanned vehicles already exist that can be adapted successfully for SaR operations in forest fires.

Field experiments were devised to mimic the entrapment conditions under the rubble of collapsed buildings aiming to investigate the evolution of volatile organic compounds (VOCs) during the early dead body decomposition stage. Three pig carcasses were placed inside concrete tunnels of a search and rescue (SAR) operational field terrain for simulating the entrapment environment after a building collapse. The experimental campaign employed both laboratory and on-site analytical methods running in parallel. The current work focuses only on the results of the laboratory method using thermal desorption coupled to comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (TD-GC×GC-TOF MS). The flow-modulated TD-GC×GC-TOF MS provided enhanced separation of the VOC profile and served as a reference method for the evaluation of the on-site analytical methods in the current experimental campaign. Bespoke software was used to deconvolve the VOC profile to extract as much information as possible into peak lists. In total, 288 unique VOCs were identified (i.e., not found in blank samples). The majority were aliphatics (172), aromatics (25) and nitrogen compounds (19), followed by ketones (17), esters (13), alcohols (12), aldehydes (11), sulfur (9), miscellaneous (8) and acid compounds (2). The TD-GC×GC-TOF MS proved to be a sensitive and powerful system for resolving the chemical puzzle of above-ground "scent of death".

Recent structural collapses were studied in order to identify gaps in technology and to propose priorities in enhancing urban search and rescue (USAR) tools. The time-lines of the events were examined with the scope of extracting critical factors that affect rescue time and can be used to define priorities in tools and technologies development, so that efficient and fast location, recovery and treatment of victims can be achieved. In this context, seven factors were identified: (1) best practices and lessons learned, (2) rescue technology, (3) community involvement, (4) information systems, (5) technology integration, (6) crisis management and (7) available budget. Each of these factors is reviewed, analyzed and discussed with the scope of providing future developments in tools and technology for USAR operations.

Fires are becoming more violent and frequent resulting in major economic losses and long-lasting effects on communities and ecosystems; thus, efficient fire monitoring is becoming a necessity. A novel triple multi-sensor approach was developed for monitoring and studying the burning of dry forest fuel in an open field scheduled experiment; chemical, optical, and acoustical sensors were combined to record the fire spread. The results of this integrated field campaign for real-time monitoring of the fire event are presented and discussed. Chemical analysis, despite its limitations, corresponded to the burning process with a minor time delay. Nevertheless, the evolution profile of CO2, CO, NO, and O2 were detected and monitored. The chemical monitoring of smoke components enabled the observing of the different fire phases (flaming, smoldering) based on the emissions identified in each phase. The analysis of fire acoustical signals presented accurate and timely response to the fire event. In the same content, the use of a thermographic camera, for monitoring the biomass burning, was also considerable (both profiles of the intensities of average gray and red component greater than 230) and presented similar promising potentials to audio results. Further work is needed towards integrating sensors signals for automation purposes leading to potential applications in real situations.

The design, development, and validation of a dynamic vapor generator are presented. The generator simulates human scent (odor) emissions from trapped victims in the voids of collapsed buildings. The validation of the device was carried out using a reference detector: a quadrupole mass spectrometer equipped with a pulsed sampling (PS-MS) system. A series of experiments were conducted for evaluating the simulator's performance, defining types and weights of different factors, and proposing further optimization of the device. The developed device enabled the production of stable and transient odor profiles in a controllable and reproducible way (relative standard deviation, RSD < 11%) at ppbv to low ppmv concentrations and allowed emission durations up to 30 min. Moreover, the factors affecting its optimum performance (i.e., evaporation chamber temperature, air flow rate through the mixing chamber, air flow rate through the evaporation chamber, and type of compound) were evaluated through an analysis of variance (ANOVA) tool revealing the next steps toward optimizing the generator. The developed simulator, potentially, can also serve the need for calibrating and evaluating the performance of analytical devices (e.g., gas chromatographers, ion mobility spectrometers, mass spectrometers, sensors, e-noses) in the field. Furthermore, it can contribute in better training of urban search and rescue (USaR) canines.

A classification of various categories of entrapped people under the ruins of collapsed buildings after earthquakes, technical failures or explosions is proposed. Type and degree of injury at the moment of building collapse and duration of entrapment are the two basic parameters in this classification. The aim is to provide sources and types of volatile organic compounds (VOCs) that can be used for establishing a new method for locating entrapped victims based on human chemical signatures. Potential target compounds, among others, are ammonia, acetone, isoprene, dimethylsulfide, dimethyldisulfide and trimethylamine. In this context, the possible neuroendocrine, metabolic and physical responses of potential victims during the different types of entrapment are correlated with the sources of VOCs such as expired air, urine, blood and sweat. The proposed classification scheme was developed as part of an integrated research project which investigates the use of combined audio, video and chemical methods for the early location of entrapped people under the ruins of collapsed buildings.

Improved data processing algorithms along with modelling techniques were employed in order to profile the responses and to assess the analytical capabilities of a system consisting of a mass spectrometer, a camera and a microphone for synchronized chemical, optical and acoustic monitoring of lab-scale fires. The combustion of cotton textile, inkjet white paper and oak wood was monitored by this system in a laboratory based environment under controlled conditions. Signal processing enabled the identification of modalities of different material burning, through the modelling and curve fitting techniques. For the chemical and optical responses, the temporal models with curve fitting were used, whereas for the acoustic signal, spectral analysis was applied for quantifying harmonics. The synergy of the three sensing technologies, augmented by signal processing and modelling, resulted in initial models, characteristic for the fire pattern for each material studied. The potentials emerged by this exploratory work needs further elaboration and elucidation, since the analytical prospective of the proposed approach is considerable and auspicious.

The late location of entrapped victims in collapsed buildings is the main reason of high mortality during urban search and rescue (USaR) operations after natural or man-made disasters. Consequently, an effort is currently being made to develop proper rescue searching tools that could improve the early location of trapped casualties. In this context, the knowledge of human scent profile and its behavior in the disaster environment is crucial. The main goal of this study was to investigate the suitability of the ion mobility spectrometry (IMS) for the quantitative monitoring of specific urine-borne volatile members of human scent interacting with the materials of collapsed dwellings. For this purpose, an ion mobility spectrometer with β-radiation source ( 63 Ni) and an in-house made filling chamber mimicking the entrapment scene were employed. In preliminary experiments, quartz sand was used as imitating debris material. The experimental setup was used to investigate the permeation properties of two very promising urine-borne species, 2-heptanone and n -octanal, under the influence of two crucial operational factors; the size of quartz grain and the quartz layer thickness. 2-heptanone was found to penetrate through quartz layer by approximately a factor 4 faster than n -octanal. The twofold and threefold increase of quartz sand thickness lengthened the permeation times on average three and seven times for n -octanal, and three and five times for 2-heptanone. The presented experimental setup can be considered as a useful tool suitable for investigating the interactions of urine markers with the debris materials in the entrapment scene. However, further investigations involving different debris materials (e.g. concrete, brick, cement, wood, plastic, glass) and other urine-borne species are necessary, prior selecting a set of volatile organic compounds (VOCs) that will support the early location method of entrapped victims.

This experiment observed the evolution of metabolite plumes from a human trapped in a simulation of a collapsed building. Ten participants took it in turns over five days to lie in a simulation of a collapsed building and eight of them completed the 6 h protocol while their breath, sweat and skin metabolites were passed through a simulation of a collapsed glass-clad reinforced-concrete building. Safety, welfare and environmental parameters were monitored continuously, and active adsorbent sampling for thermal desorption GC-MS, on-line and embedded CO, CO2 and O2 monitoring, aspirating ion mobility spectrometry with integrated semiconductor gas sensors, direct injection GC-ion mobility spectrometry, active sampling thermal desorption GC-differential mobility spectrometry and a prototype remote early detection system for survivor location were used to monitor the evolution of the metabolite plumes that were generated. Oxygen levels within the void simulator were allowed to fall no lower than 19.1% (v). Concurrent levels of carbon dioxide built up to an average level of 1.6% (v) in the breathing zone of the participants. Temperature, humidity, carbon dioxide levels and the physiological measurements were consistent with a reproducible methodology that enabled the metabolite plumes to be sampled and characterized from the different parts of the experiment. Welfare and safety data were satisfactory with pulse rates, blood pressures and oxygenation, all within levels consistent with healthy adults. Up to 12 in-test welfare assessments per participant and a six-week follow-up Stanford Acute Stress Response Questionnaire indicated that the researchers and participants did not experience any adverse effects from their involvement in the study. Preliminary observations confirmed that CO2, NH3 and acetone were effective markers for trapped humans, although interactions with water absorbed in building debris needed further study. An unexpected observation from the NH3 channel was the suppression of NH3 during those periods when the participants slept, and this will be the subject of further study, as will be the detailed analysis of the casualty detection data obtained from the seven instruments used.

The different aspects of sensors integration, and specifically that of a Mass Spectrometer (MS) with audio and video signals, are investigated for detecting and monitoring indoor fire events. The present study focuses on comparing the capabilities of a variety of chemical sensors, on answering technical challenges in regard to the integration of chemical, audio and video signals and on discussing integration issues for potential field applications. Controlled, small scale fire experiments were carried out in the laboratory. A commercial MS coupled with an in-house developed Pulsed Sampling System (PSS), was used for on-line sampling and near real-time monitoring of the evolved volatiles. The detection limit of PSS-MS was found to be 150ppbv and its linearity was confirmed up to 10ppmv using benzene gas standards. The profiles of ions with m/z 57, 78, 91 and 106, corresponding to indicative Volatile Organic Compounds (VOCs) of the fire event, were recorded and compared with the concentration profiles of CO2, CO, O2, NO and H/C (C3H8), acquired by the gas sensors of a commercial exhaust gas analyzer. Audio and video signals were recorded by a microphone and a visual camera, simultaneously, with PSS-MS data. Two types of fire experiments were performed in order to simulate field conditions: (a) direct fire monitoring, in case of unobstructed direct fire view and (b) indirect fire monitoring through reflection of audio and video signals on metallic surfaces, for simulating obstacles preventing direct fire view. The information derived by audio and video signals reaffirmed the chemical detection inferences for both types of fire experiments, thus increasing the credibility of each individual method. Occasionally, video, audio and chemical information were complementary, thus counterbalancing the detection limitations of the individual methods. The integrated approach of combining MS data with audio and video signals appears to be a promising method in safety and security applications, where reliable, early detection and real-time monitoring is necessary.

Blends of nitrile butadiene rubber (NBR) with polyvinyl chloride (PVC) are widely used in products such as hoses and seals. As part of a project that uses NBR/PVC blends for manufacturing forest fire hoses, blends of NBR/PVC with various inorganic fillers, such as Mg(OH)2, china clay (organic modified kaolin) and nano clay (organic modified bentonite) were studied by TG–MS. No significant changes were observed to the type of the polymers’ decomposition products, compared to that of NBR/PVC blend without additives. The most remarkable change was the absence of HCl from decomposition products in the presence of the Mg(OH)2 additive.

As the body decays shortly after death, a variety of gases and volatile organic compounds (VOCs) constantly emanate. Ethical and practical reasons limit the use of human corpses in controlled, time-dependent, intervening experiments for monitoring the chemistry of body decay. Therefore the utilization of pig carcasses serves as a potential surrogate to human models. The aim of this work was to study buried body decay in conditions of entrapment in collapsed buildings. Six domestic pigs were used to study carcass decay. They were enclosed in plastic body bags after being partially buried with rubbles, resembling entrapment in collapsed buildings. Three experimental cycles were performed, employing two pig carcasses in each cycle; VOCs and inorganic gases were measured daily, along with daily visible and thermal images. VOCs were collected in standard sorbent tubes and subsequently analyzed using a Thermal Desorption/Gas Chromatograph/high sensitivity bench-top Time-of-Flight Mass Spectrometer (TD/GC/TOF-MS). A comprehensive, stage by stage, detailed information on the decay process is being presented based on the experimental macroscopic observations, justifying thus the use of pig carcasses as surrogate material. A variety of VOCs were identified including almost all chemical classes: sulfur, nitrogen, oxygen compounds (aldehydes, alcohols, ketones, acids and esters), hydrocarbons, fluorides and chlorides. Carcasses obtained from a pig farm resulted in more sulfur and nitrogen cadaveric volatiles. Carbon dioxide was by far the most abundant inorganic gas identified along with carbon monoxide, hydrogen sulfide and sulfur dioxide. Visual monitoring was based on video captured images allowing for macroscopic observations, while thermal camera monitoring which is mostly temperature dependent, resulted in highlighting the local micro-changes on the carcasses, as a result of the intense microbial activity. The combination of chemical and optical methods proved very useful and informative, uncovering hidden aspects of the early stages of decay and also guiding in the development of combined chemical and imaging methods for the detection of dead bodies.

A risk assessment framework was used to assess the risks of forest fire smoke (ffs) to the exposed communities, critical infrastructures and the environment. The present work is focused on the planning and problem formulation phases of this risk assessment procedure. Specifically, as part of the problem formulation phase, integration of the available ffs chemical data was carried out by answering critical questions regarding the ffs. In this way, critical factors have been identified, which mostly define and characterize ffs as a cause of problems and possible symptoms. The integrated information can be used in order to determine assessment endpoints, conceptual models, and risk hypotheses, as presented in an indicative example referred to a simple risk scenario. This work, enhanced with additional risk scenarios, can be used for the next phases of the risk assessment procedure, such as risk analysis and risk characterization. Future research needs for adequate evaluation of ffs impacts on communities, infrastructures, and the environment are also discussed.

In the present study, the time profile, measured as "accumulation", of volatile organic compounds (VOCs) produced during the early stages of human decomposition was investigated. A human cadaver was placed in a sealed bag at approximately the 4th day after death. Evolved VOCs were monitored for 24 h by sampling at different time intervals. VOCs produced were analyzed by thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS). Over 30 substances were identified in total. These included mainly aliphatic and aromatic hydrocarbons, oxygenated compounds (alcohols, aldehydes, ketones) and organic sulfides. The last were the most prominent class of compounds identified. Eleven compounds were present in all the sampling cycles and constitute a "common core": ethanol, 2-propanone, dimethyl disulfide, methyl benzene, octane, 2-butanone, methyl ethyl disulfide, dimethyl trisulfide and o-, m- and p-xylenes. The last sampling cycle yielded the most abundant compounds in number and quantities. Inorganic gases such as CO2, CO, NH3 and H2S were also determined. The fundamental physicochemical properties of the evolved VOCs were used for evaluating their environmental impacts. It appears that the decay process, which is a dynamic procedure, can provide chemical signals that might be detected and properly evaluated by experts in the fields of forensic sciences, search and rescue units and environmental scientists.

Expired air chemical analysis is investigated as a search and locate method for the early detection of entrapped people under the ruins of collapsed buildings after an earthquake. Fasting individuals were examined as a group that simulates the medical status of some of such victims. Exhaled air from seven fasting male monks (after 63h) was analysed using thermal desorption–gas chromatography–mass spectrometry (TD–GC–MS) analysis. Over 150 volatile organic compounds (VOCs) were identified and the 43 most frequent are presented. Acetone showed by far the highest “positive alveolar gradient”. Other compounds included phenol, di-limonene, 2-pentanone, isoprene and acetaldehyde. Quantitative results showed a 30-fold increase of acetone concentration (5.8ppmv) compared to control measurements of a volunteer. Breath acetone was also identified through a portable gas chromatography-ion mobility spectrometer showing possible, under certain conditions, effectiveness of the method in the field.

A case study of a real forest fire incident is presented, where field measurements held out near the flame-front in smoky, hostile conditions. Permanent gases, such as CO, CO2, NH3, volatile organic compounds (VOCs) and particulate matter (PM2.5, PM10) were monitored. Complexity and possible origin of some of the forest fire smoke components are examined and discussed; styrene identified seems that was originated mostly from the combustion of plastics, due to the forest fire expansion to a plastics storehouse. A new approach, regarding the chemical composition of forest fire smoke and possible origin of smoke components depending on the flame-front expansion (e.g. to rural fields, rural and urban constructions or landfills), is presented in the format of a road-map. The case study tests part of the validity of the road-map, which could be used for air-quality indications and risk assessment in a forest fire. Criteria for monitoring air-quality in a forest fire, for health and safety issues, are also discussed.

Thermogravimetry-massspectrometry (TG-MS) was used to study the effect of the inorganic salts (NH4)2SO4 and (NH4)2HPO4,active substances of many commercial forest fire retardants, on the pyrolysisof Pinus halepensis needles and their maincomponents (cellulose, lignin and extractives). These salts seemed to affectthe pyrolysis of cellulose by increasing significantly the char residue, decreasingthe pyrolysis temperature and changing the composition of the evolved gases,that is, increasing levoglucosenone and decreasing oxygen containing volatileproducts. (NH4)2SO4seemed to have negligible effect on the pyrolysis of lignin, while (NH4)2HPO4 increased the char residue and decrease the relative contribution of guaiacolsin the evolved gases. No effects of the inorganic salts on the extractiveswere observed. Finally, the inorganic salts seemed to affect the pyrolysisof pine-needles, mainly the cellulose component, but the effects were notas intense as in the pyrolysis of cellulose.

In this work a new method called TG-bridge/mass spectrometry is presented, for the on-line monitoring of the pine needles combustion emissions in a common lab furnace. The TG-bridge (thermogravimetry-bridge) system has been developed in-house as a TG-MS (thermogravimetry-mass spectrometry) interface, for TG-MS analysis. In this work, TG-bridge was used for directly sampling of the combustion emissions from the inside of the furnace and transferring them into the mass spectrometer (MS), without disturbing the sub-pressure conditions inside the MS ion source. The effect of Fire-Trol 931 (a long-term fire retardant) on the emissions, produced during the combustion of pine needles, is tested in the lab for future application in the field. It was shown that in treated samples, increased evolution of ammonia and aromatic compounds took place, compared to untreated samples. Maximum concentrations of specific compounds, such as benzene and toluene, evolved during the combustion experiments in the furnace, were determined.

Discriminant Analysis is used as a part of a research, which aims at using expired air analysis for the early location of entrapped people under the ruins of collapsed buildings in an earthquake. This work focuses on the possibility of distinguishing Volatile Organic Compounds (VOCs) in the entrapment area which originate from different sources. Five categories of samples were analyzed by Thermal Desorption-Gas Chromatography–Mass Spectrometry (TD-GC–MS). Expired air samples from healthy humans (Category 1) and fasting people (Category 2) were analyzed for studying the VOCs attributed to entrapped people. Headspace air of urban waste disposal bins (Category 3), headspace air of bags with decaying human bodies (Category 4) and urban air samples (Category 5) were analyzed for studying the VOCs attributed to background sources. Discriminant Rotation, a specific type of Discriminant Analysis was applied on the VOCs concentration matrix of the five categories. Combinations of VOCs that best discriminated each category were determined. Cluster Analysis was used to validate the results of Discriminant Analysis. The advantages and limitations of the method are presented and discussed.