Real Time Detection Systems


Thursday, May 26, 2016, 8:00 AM - 11:00 AM


Field—portable Gas Chromatography—Mass Spectrometry Used to Identify Unknown and Unexpected Airborne Stressors

P. Smith and J. Lodwick, U.S. Department of Labor - OSHA, Sandy, UT

Objective: To understand the processes and mechanisms that generate air contaminants. To identify causative stressors when unexplained medical conditions are observed; especially in situations where the presence of specific important contaminants is unknown and unexpected.

Methods: Person portable gas chromatography-mass spectrometry (GC-MS) instrumentation was used in the laboratory to develop sampling methods compatible with the instrument for use in field investigations. These methods were then used in the field to complete two investigations where worker medical conditions raised important exposure questions. Both solid phase microextraction (SPME) and needle trap (NT) sampling are compatible with solventless sample introduction into the heated injector of the GC-MS instrument used. Methods were developed for both sampling approaches to screen materials, for general area air samples to identify or rule out expected stressors, and to identify unknown/unexpected airborne stressors.

Results: Both SPME and NT sampling ruled out exposure to toluene, although several materials with other solvents (methylene chloride, perchloroethylene, and Stoddard solvent) were identified in a fabric printing shop. Both sampling methods identified and unexpected exposure to aniline and p-toluidine an exposure scenario where a worker spent <1 hour cleaning out a tank that held solidified material derived from methylene diphenyl isocyanate (MDI). Worker suffered a rapid onset methemoglobinemia.

Conclusions: The use of both sampling approaches with the person portable GC-MS instrument used in the field was instrumental in identifying or ruling out important airborne stressors in cases where medical outcomes implicated workplace exposures. , Prior to the field work, there was no information on the causative exposure that produced the near-fatal medical condition in the worker who cleaned the MDI tank, nor was there any understanding of a process or mechanism that may have led to the formation of methemoglobinemia inducing agents within the tank. The identification of the likely causative airborne stressors allowed further work to understand the underlying chemical processes. The new sampling methods developed in the laboratory differentiate the field work completed from a simple case study, and the field work validated the usefulness of the sampling and field analysis approaches used.



Evaluating the Usefulness of Gaseous FTIR Spectroscopy

L. Knoch, Army Public Health Center (Provisional), Aberdeen Proving Ground, MD

Situation/Problem: When industrial hygienists monitor exposures, real-time sampling can be critical to detecting overexposures. Instantaneous overexposures often are undetected when sampling industrial processes and operations using traditional industrial hygiene sampling methods. The ability to quantify contaminants real-time during workplace monitoring offers significant advantages. Real-time gas/vapor monitoring is especially relevant due to the number of chemicals that have short term exposure and/or ceiling limits. In addition, cross interferences can create an exhaustive nuisance for industrial hygienists in complex sampling environments.

Resolution: Innovative Fourier Transform Infrared (FTIR) spectrometers are becoming more accurate, tough, and convenient to use. Due to molecular fingerprinting abilities, FTIR technology is emerging as the cutting edge solution to workplace monitoring problems. Comparable to direct-reading single-beam infrared spectrophotometers, FTIR spectrometers can analyze up to fifty gases simultaneously and detect unknowns. Due to the ruggedness of the instrument and particle filters, the FTIR can be used to sample in most types of environments.

Results: Toxic gas sampling methodologies for a variety of workplace environments will be compared. Sampling capabilities and limitations of an array of instruments and examples of real-life sampling methods will be presented. Pros and cons of various portable, direct-reading instruments and rationale for instrument selection will be presented. The capabilities and accuracy of gas-phase FTIR spectroscopy proves to be superior to other direct-reading instrumentation.

Lessons learned: Instantaneous short-term exposure monitoring for gases/vapors is achievable using state of the art FTIR technology. Future research on instrument design should continue to focus on shrinking the overall instrument size, increasing the accuracy, and improving the signal to noise ratio.



Evaluation of Personal Breathing Zone and Area Airborne Diacetyl and Other Volatile Organic Compounds (VOCs) at a Commercial Coffee Roasting Facility via Real-Time Fourier Transformed Infrared Spectroscopy (FTIR)

M. McCoy and K. Parr, GZA GeoEnvironmental, Inc., Waukesha, WI; J. Cornish, Gasmet, Bellingham, WA; J. Greivell, RAECO, Butler, WI; M. Haapala, Gasmet Technologies Oy, Helsinki, Finland

Situation/Problem: Recent scientific literature has identified the airborne presence of diacetyl and 2,3-pentanedione at concentrations nearing or potentially exceeding the current ACGIH® Threshold Limit Values (TLVs®) at commercial coffee roasting facilities. A large commercial coffee roaster wished to determine its employee breathing zone exposures to these VOCs during various work activities including large-scale coffee bean roasting and grinding, as well as in the general work environment. The coffee roaster was concerned about potential worker inhalational exposure and the potential for adverse health effects.

Resolution: Workers were monitored for 8-TWA exposures to alpha diketones, as well as for task-based, short-term exposures for 15 minute periods during specific roasting and grinding processes. Airborne temperature and relative humidity were also evaluated during the study. The authors utilized an AIHA certified laboratory for the analysis via modified OSHA method 1012 for the sensitive and specific quantification of diacetyl and 2,3-pentanedione by gas chromatography with electrochemical detection (ECD). Additionally, the authors performed real-time FTIR analysis of breathing zone and area workplace air for VOCs to determine the sources, as well as quantify and identify various VOCs in the close proximity of roasting and grinding activities. Real-time FTIR provided both identification and quantification of both diacetyl and 2,3-pentanedione, as well as other VOCs generated during coffee bean roasting and released during grinding operations.

Results: Airborne concentrations of diacetyl in the worker’s breathing zone for 8-hour TWAs were less than the ACGIH® TLV® for diacetyl, and 2,3-pentanedione was non-detectable by standard laboratory methods. Two short-term breathing zone samples revealed airborne concentrations for diacetyl exceeded the ACGIH® STEL of 0.02 ppm. FTIR analysis of air collected from both the breathing zone and the workplace area air samples revealed low concentrations of various VOCs. Diacetyl and 2,3-pentanedione were detected in breathing zone and area samples at concentrations less than the limit of detection for the FTIR methods. However, when air samples were collected for FTIR analysis from the headspace of bags of freshly ground beans, elevated concentrations of diacetyl, acetaldehyde, carbon monoxide, carbon dioxide as well as other VOCs were detected. Concentrations of these gases rapidly deceased with increasing distance from the freshly ground beans, and neither breathing zone or area workplace air samples reflected hazardous atmospheres in these conditions.

Lessons learned: Coffee roasting and grinding, with adequate ventilation and proper roasted bean handling and grinding, appear to generate minimal worker breathing zone exposure to diacetyl and 2,3-pentanedione. It appears from this study that roasted coffee beans naturally generate alpha diketones and other VOCs as naturally occurring compounds resultant of the roasting process. Real-time FTIR proved to be both beneficial in quantifying as well as identifying various VOCs during coffee roasting and grinding operations. Small scale and micro roasting operations, based on their individual ventilation conditions, may need to consider monitoring for alpha diketones as well as other VOCs during roasting and grinding operations.



Handheld Non-Dispersive Infrared (NDIR) Sensing for Field Detection of Light Hydrocarbon Gases

J. Hill and P. Smith, USDOL/OSHA, Sandy, UT

Objective: When assessing airborne light hydrocarbon concentrations, handheld multi-gas meters are often used to quantify exposures and assess potentially flammable environments. During oilfield activities, hydrocarbon concentrations greater than the LEL may be encountered and proper LEL assessments are essential to worker protection. When detectors are not accurately calibrated or calibrated with a gas dissimilar to the environment being tested, knowledge of potential hazards isn't reliable. Field users may make decisions resulting in hazardous working conditions. To better understand the impacts of gas detection when calibrated to a different gas, tests conducted in a laboratory setting provided valuable information for field personnel when determining multi-gas meter response in varying conditions.

Methods: Due to limitations of catalytic combustion sensors to values below the LEL, non-dispersive infrared (NDIR) detection was selected as a means to evaluate hydrocarbon gas concentrations ranging from 0 to 100 vol%. Instruments with NDIR sensors were exposed to methane, propane and butane to determine response accuracy when calibrated to one gas but exposed to a different flammable gas. A wide range of concentrations were generated in 5 layer bags for methane, propane, and butane ranging from 10 to 100 vol% to determine NDIR sensor response.

Results: Analysis of the data indicated loss of accuracy for scenarios when calibration to methane occurs but detection of propane or butane is necessary. Strong linearity was identified when meters are calibrated to methane and methane was monitored (slope=1.0, r2 > 0.99). In addition, in low concentrations (less than 6 vol%), propane was linearly detected using a meter calibrated to methane but higher propane concentrations caused the meter to read out “over limit” results due to the greater molecular IR absorptivity of propane compared to methane.

Conclusions: This demonstrates a need to determine the composition of potential flammable gases to be encountered when calibrating handheld portable multi-gas meters for detection of gas concentrations greater than LEL values. For reliable results in the field, one must use a sensor that measures the gas to be encountered and that sensor must be calibrated to the appropriate gas to ensure results are accurate and representative of the actual airborne concentrations.



A Portable Colorimetric Biosensor for Real-Time Personal Exposure Assessment to Bisphenol A in Indoor Environments

R. Alkasir, A. Rossner, and S. Andreescu, Clarkson University, Potsdam, NY

Objective: Bisphenol A (BPA) is a phenolic compound commonly used in the plastics industry that can result in human exposure and potentially lead to behavioral, reproductive, developmental, and neurological disorders. While relatively high concentrations of BPA are released in the living environment, there is a lack of temporal and spatial resolution data to characterize BPA exposure. An improved understanding of the exposure response effects requires field deployable instrumentation that can be used for rapid multisite monitoring in the living environment.

Methods: To facilitate spatiotemporal measurements of BPA exposure, we have designed a compact portable colorimetric paper based biosensing device with integrated sampling/analysis units for field-based measurements of BPA. The system employs interchangeable BPA responsive paper sensors as a colorimetric test zone for BPA. Sample analysis through measurement of color intensity was made directly on the sensing pad, immediately following sample aspiration. The sensor was validated with the conventional Gas Chromatography (GC) method and used to detect BPA exposure in household dust.

Results: The sensor enabled selective detection of BPA with a detection limit of 0.28 µg/g. Sensor data was gathered as a visual color change with the naked eye and by using common image analysis software such as Adobe or Image J, or with an iPhone. BPA concentrations in household dust samples ranged from 0.05 to 3.87 µg/g. Side-by-side comparison of BPA concentrations in the household dust samples shows excellent correlation between the two methods: portable biosensor and GC.

Conclusions: This study demonstrates the feasibility of low cost paper based devices with biomolecular recognition as reliable detection tools for field based assessment of BPA exposure in dust samples. Advantages include on-site measurements, ease of use, real-time detection and reagentless operation with all in one sampling, extraction and analysis. The system could be adapted to other chemicals such as volatile organic compounds (VOCs), phthalates and pesticides, and can be used in homes, day care centers, schools and the work environment.



Real-Time Particulate and Toxic-Gas Sensors for Firefighters

F. Takahashi and C. Liu, Chemical Engineering, Case Western Reserve University, Cleveland, OH; P. Greenberg, G. Hunter and M. Kulis, NASA Glenn Research Center, Cleveland, OH; G. Hunter, NASA Glenn Research Center, Cleveland, OH; S. Carranza and D. Makel, Makel Engineering, Inc., Chico, CA

Objective: Removal of respiratory protection during fire overhaul activities can expose firefighters to unknown toxicants, but current practice relies solely on the Carbon Monoxide concentration. Wildland firefighters do not even wear respiratory protection despite low-level but long-term exposure to smoke. Simultaneous monitoring of particulates, aldehydes (formaldehyde and acrolein), and hydrocarbons are needed as they include carcinogens and exceed frequently the exposure limits during fire overhaul and wildland firefighting. The purpose of this project is to develop prototypes of compact, highly sensitive, real-time particulate/gas detection systems to reduce the number of firefighter fatalities and injuries.

Methods: This study endeavors to: (1) combine the NASA developed compact particulate and gas (O2, CO, and hydrocarbons) sensors, (2) micro fabricate and integrate new sensitive aldehyde sensors, and (3) test prototypes in the laboratories, burn rooms, fire overhaul, and wildland fire environments.

Results: The preliminary testing of existing particulate and micro fabricated gas sensors was conducted in a controlled burn room using different fuels and in the laboratory using smoke from wood samples being pyrolyzed in a tube furnace. The preliminary testing resulted in further understanding of the device responses and room for improvement.

Conclusions: The preliminary testing of the previously developed particulate and gas sensors demonstrated their performance and potential. Additional micro fabricated sensors for the aldehydes are being developed. Compact real-time particulate and toxic-gas detectors to be derived from the prototypes under development can be adopted by fire services eventually in the future.



Practicalities & Early Lessons: Small Unmanned Aerial Platforms for Monitoring Stressors

R. Eninger, Air Force Institute of Technology, WPAFB, OH; K. Fullerton, US Air Force School of Aerospace Medicine, WPAFB, OH

Situation/Problem: Rapidly developing unmanned aerial technologies are offer the potential for a novel, mobile sensing platform for use by environment, safety & occupational health professionals and in related disciplines. Employment of small unmanned aerial systems (SUAS) for these purposes is nascent and has yet to develop standard practices and specifications. In particular, improvements in sensor design, employment, and interoperability are needed to foster wider adoption. Currently, sensor solutions tend to be customized for a chosen airframe.

Resolution: The literature was reviewed and two distinct pilot efforts were undertaken to develop airborne platforms for chemical and aerosol monitoring. The first effort pursued a design to locate chemical emissions using micro aerial vehicles. The second effort attempted to design and fly a platform for monitoring combustion emissions. Through these efforts, practical lessons were garnered across the planning, design, development, and attempted employment phases.

Results: Observations were made on operator/pilot requirements, controls, sensor employment, and platform characteristics which impacted the feasibility of operations. Claims for UAS efficacy for use in environmental monitoring should be viewed with some skepticism based upon complexities that are yet to be worked out.

Lessons learned: An interdisciplinary approach is required to effectively design, plan, and employ small unmanned aerial systems for monitoring of stressors. The technology is not sufficiently mature to consider these capabilities for routine employment but does have promise to do so in the future. A trade-off occurs between payload, flight time, and sensor detection limit/sophistication. These are additional considerations when formulating data quality objectives.



Lessons Learned in Selecting an All-Hazards Equipment Suite of Direct Reading Instruments

C. Baker, Alliance Solutions Group, Inc., Helotes, TX; R. Campbell, Alliance Solutions Group, Inc., Newport News, VA; W. Weisman, Consulting, Newport News, VA

Situation/Problem: Any organization purchasing direct reading equipment knows the challenges of selecting the right tool for the job, even if the hazards are known. Take this situation and apply it to an organization with one hundred seventy branches in nine countries responsible for protecting workers and the surrounding communities from known and unknown hazards; the combination of challenges skyrocket. This presentation will cover the process used to select a comprehensive, standardized package of direct reading equipment for teams of occupational health and emergency response specialists engaged in global operations.

Resolution: The effort focused on identifying best of breed instruments that addressed global and local risks, satisfied the technological capability needs, and balanced the selection based on life-cycle cost and ease of user interface. An organization wide equipment list was stratified by target capability (e.g., radiological, VOC, high volume air sampler, biological agent, etc.) and if it could detect, identify, and/or quantify hazards. From this, a set of instruments with similar capabilities was scored on its ability to address the risks and satisfy the technical criteria (e.g., instant quantification of gamma radiation). These factors included: life-cycle cost, operations and maintenance schedule, anticipated lifespan, supply-chain availability, consumable and accessory shelf life, power source, value, user feedback, training time required for proficiency, and other practical considerations—are the buttons big enough to push when in Level A PPE?

Results: Each item selected filled a specific need in the teams’ all-hazards direct reading equipment suite. Some duplication of capabilities was intentionally incorporated into the final equipment suite to ensure field teams had redundant capability.

Lessons learned: Thousands of hours of real world responses and all-hazards exercises, using the recommended equipment set, provided lessons learned about the equipment, how well users were able to choose the best instrument based on time constraints and available information, and how standardization improved cost, logistical support and streamlined training efforts.



The Role of Data Science on the Industrial Hygiene Team

R. Reed, University of Arizona, Tucson, AZ

Situation/Problem: Advances in data collection (such as sensors), data storage, and data processing technologies have opened the hypothetical data flood gates. Today, data science drives marketing, political campaigns, and it even drives cars. Data science could and should be utilized for improving industrial hygiene, but our field has yet to embrace it. The objective of this presentation is to deepen understanding of data science, its impact on health and safety, and help quicken the pace at which IHs see utilization and improvement.

Resolution: Data science is simply the aggregation of 1) field expertise (Industrial Hygiene), 2) some statistical knowledge, and 3) some computer programming skills. Certain predictive data science techniques were developed with human brain physiology in mind and are a form of ‘machine learning’. Machine learning techniques can continue to model and improve their predictions, sometimes without human supervision.

Results: Data science has already invaded occupational health and safety. Some companies use it to predict when workers are too fatigued to operate heavy equipment based on wearable monitors or anomalies in every day, measurable behaviors. Other applications for data science include predicting measures that are otherwise too difficult or costly to collect. Further insight and predictive capabilities can be gleaned from data already collected, such as machine health. Future wearable, real-time sensors will measure several contaminants at once and predict risk based on a host of inputs.

Lessons learned: Several barriers will slow the application of data science to industrial hygiene. While sensor technology, data integration and processing power continue to be barriers in some cases, they will quickly be overcome. Other issues include the ethical premise of activity monitoring, and the effect risk prediction could have on individual risk aversion. While many questions remain unanswered, for now, industrial hygienists should 1) understand the benefits and challenges that data science will bring, 2) be proactively involved in the discussions and actions that will shape the future of health and safety, and 3) think outside of the box, integrate ideas from other life and work experiences, and apply them to the work of improving health and safety.​