Drilling and blasting during the construction of tunnels generate large amounts of dust. Accurately predicting dust yield helps to formulate effective dust control measures that can be employed to reduce worker exposures. However, current dust yield prediction methods mainly rely on empirical formulas for open-pit blasting, which do not fully account for the combined effects of ventilation, rock type, and environmental conditions. This paper uses a railway tunnel as a case study and analyzes the dust dispersion patterns based on on-site measurements. Through numerical inversion, a dynamic correlation model between dust concentration at monitoring points and total dust generation was established, and sensitivity analysis of influencing factors was conducted using the Whale Optimization Algorithm-Deep Extreme Learning Machine (WOA-DELM) neural network. A new calculation formula for tunnel blasting dust yield is proposed. The results showed a bimodal dispersion pattern: the initial dispersion was driven by the blasting shock wave, while the secondary dispersion was caused by mechanical ventilation. The surrounding rock type was the most significant factor affecting dust yield, with a variation of up to 8.04 kg. Other factors influencing yield included tunnel temperature (0.97 kg/°C), humidity (0.74 kg/%), tunnel water-content level (0.51 kg per level on a field-based 1-10 scale) and distance from the monitoring point to the tunnel face and ventilation duct outlet (0.17 kg/m and 0.02 kg/m, respectively). By using the WOA-DELM neural network to optimize the traditional open-pit blasting dust calculation formula, an average prediction error of 4.6% was achieved. The research results provide a scientific basis and parameter guidance for developing data necessary to implement engineering controls for tunnel dust control.
Graphene is among the most utilized nanoscale materials in the United States. It is a single-layer carbonaceous nanoscale material with a hexagonal structure. Subtractive synthesis from graphite is common in high-volume manufacturing, with graphene and graphite often present within the same workplace. There is little worker exposure data available to inform risk assessments, particularly for graphene. Dustiness determinations using EN15051-2 Workplace Exposure-Measurement of the Dustiness of Bulk Materials. Part 2: Rotating Drum Method were conducted for two graphene nanoplatelets, two graphene oxides, one few-layered graphene, one furnace carbon black, three natural and five synthetic graphites, and two coals. All 16 test materials were composed mostly of carbon. Dustiness determinations were compared to established thresholds for the inhalable, thoracic, and respirable particle size fractions. Measurements of specific surface area, moisture content, and unconsolidated bulk density were further obtained. Particles were imaged through scanning electron microscopy. The EN15051-2 test is a gentle gravity-induced procedure where the test material falls a limited distance. Dustiness determinations resulted in 2.2% or less of the test material collected in the inhalable size fraction, 0.89% or less in the thoracic, and 0.37% or less in the respirable subfraction. The thoracic fraction constituted ∼31% of the inhalable fraction overall. The masses of four of five graphenes were below the gravimetric limit of detection of 0.57 µg in the respirable size fraction. Contributing factors were the gentle nature of the test and low unconsolidated bulk densities (5.9 to 174 kg/m3) for the nanoscale materials, resulting in 0.21 to 6.1 g loaded masses. Modest enhancements to the testing protocol could potentially improve quantification for low-density materials. All test materials and quantifiable size fractions were classified as moderate or high dustiness on a mg/kg basis. The carbonaceous materials in this study have a moderate to high propensity of becoming airborne when subjected to a gentle gravity-induced stimulus. Without adequate controls to prevent dust emissions, handling could result in inhalation, dermal, and mucous membrane exposures as well as present slip, electrical, fire, and dust explosion hazards.
Powered air-purifying respirators (PAPRs) are an important and commonly used form of respiratory protection in healthcare, particularly during high-risk clinical activities. The main purpose of this study was to determine the simulated workplace protection factor (SWPF) for several PAPR models, investigate the effects of simulated healthcare exercises on individual exercise SWPFs (SWPFi), and monitor for the occurrence of over-breathing during testing. Ten human subjects participated in this study, each performing a series of 10 simulated healthcare exercises lasting two minutes each for five loose-fitting and one tight-fitting PAPR, repeated three times. Two scanning mobility particle sizers were used to measure the aerosol concentration inside and outside the respirator synchronously, with the overall SWPF determined by taking a ratio of the two aerosol concentrations. Significant differences in the geometric mean (GM) of the overall SWPF were found among different PAPR models. A safety factor of 10 (SF10) was applied to the 5th percentile SWPF to adjust for uncertainties between simulated and actual workplace settings. With this factor applied, two PAPRs exceeded the Assigned Protection Factor (APF) of 1,000, one (loose-fitting helmet) exceeded the APF of 25, and three models did not achieve the APF of 1,000. The findings suggest that a safety factor of 10 may be too conservative for PAPRs, and their appropriate application remains an important consideration in SWPF studies. Significant differences in SWPFi were observed across exercises, with lower-demand exercises yielding more conservative protection estimates. Over-breathing was not observed during any of the simulated healthcare exercises. Future studies with larger sample sizes and a broader range of PAPR models are needed to better establish the relationship between safety factor application and the APF, and to further evaluate the effects of exercise on SWPFi. The findings of this study may inform the development of an ASTM draft standard for methods to measure respirator SWPFs.
The sporadic occurrence of contradictory lab results regarding the presence of asbestos in building materials has raised questions about the quality of routine analyses performed by labs that offer their services on the Swiss Asbestos Forum (FACH) website, which is administered by the Swiss National Accident Insurance Fund (Suva). These labs have committed to a careful preparation of "difficult" samples, such as window putty, tile adhesive and other materials containing often low concentrations of asbestos, so as to increase the likelihood of detection. Most of the labs are accredited for asbestos analysis by their respective national accreditation body, and all have regularly passed proficiency testing (PT) schemes such as the Asbestos in Materials Scheme (AIMS) of the Health and Safety Executive (HSE, Buxton, UK) or the Bulk Asbestos Proficiency Analytical Testing (BAPAT) provided by the American Industrial Hygiene Association (AIHA, Falls Church, VA). Sample sets of pre-tested building materials were shipped to these labs from unsuspicious senders at irregular intervals, approximately once per year since 2019. Error rates were high at the beginning of the program, with a maximum of 17% false negative results in the second round, decreasing to less than 5% in subsequent rounds. The rate of false positives was markedly lower, with a maximum of 3% in the first of five rounds. Overall, Swiss labs performed better than non-Swiss labs, and concentrations greater than 1% were correctly detected more often than those of lower concentrations. The method used (mostly polarized light microscopy (PLM) or scanning electron microscopy (SEM)), as well as accreditation and price of the analyses, did not significantly influence analysis outcomes. Approximately half of the laboratories provided an estimate of the asbestos content in the samples, often with significant discrepancies between individual and reference laboratories. The use of SEM analysis has led to significantly higher asbestos content estimates than PLM analysis.
Violence against healthcare workers (HCWs) is a growing global concern. In the wake of the pandemic, HCWs are subjected to physical and verbal violence more than ever before. This violence is largely unreported, and therefore, the true scope of the problem is unknown. Violence training is mandated in many jurisdictions; however, this has usually been online or classroom-based learning with hypothetical scenarios. Virtual reality (VR) offers a unique opportunity for HCWs to interact in violent scenarios to learn and practice de-escalation techniques. This research focuses on VR training of physicians in a 1-hour session with both quantitative and qualitative feedback from participants. The 27 physicians who participated showed statistically significant positive shifts in self-reported confidence in handling potentially violent situations and understanding of basic verbal de-escalation techniques. In addition, the participants consistently rated the VR training tool extremely high across all core evaluative domains, confirming its strong perceived usability, realism, engagement, satisfaction, and value. Notwithstanding logistical challenges and the need for longitudinal follow-up to test real-life impacts, VR allows physicians to practice their ability to interact with potentially violent patients or their families in a safe manner, which could increase their confidence in de-escalation skills and response to high-risk/violent incidents.
Studies have shown that industrial hygiene exposure assessments are subject to inaccurate judgment, may not be different from random chance, and may be biased low, resulting in underestimation of exposures. However, these limitations can be mitigated by the use of modeling and statistical tools. This study shows that before sample collection or when few samples have been taken, modeling tools such as the Structured Deterministic Model (SDM) 2.0 and Expostats can augment a practitioner's risk communication to an employer. SDM and Expostats were used to analyze compliance datasets as follows: (1) comparing the performance of the SDM tool to predict airborne lead and silica overexposures as confirmed by sample data; (2) comparing statistical outputs for similar exposure groups (SEGs) between initial samples that did not contain overexposures and respective follow-up samples that did contain overexposures for airborne lead and iron oxide, and noise; and (3) statistical analysis of airborne lead and silica, and noise datasets that did not contain overexposures to determine the prevalence of unacceptable overexposure risk. In evaluation one, SDM correctly predicted overexposures in all SEGs where samples were above the exposure limit. Evaluation two results showed that inferential statistics from the initial results indicated an unacceptable risk of overexposure, and this was confirmed by follow-up samples that contained overexposures. In evaluation three, results suggested an unacceptable risk of overexposure in half of the datasets analyzed. The results of this study demonstrate that compliance-focused practitioners could also voluntarily leverage modeling and statistical outputs to communicate overexposure risk and encourage controls to reduce the risk of future occupational illnesses and compliance activity.
In December 2019, Coronavirus Disease 2019 (COVID-19) caused by infection with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) was first identified in Wuhan City, Hubei Province, China, and rapidly spread across the globe, affecting millions and overwhelming global public health systems. To evaluate the incidence and severity of head and face device-related pressure injuries (DRPI) among front-line nurses and identify factors contributing to DRPI, from March to May 2020, 143 clinical first-line nurses from Guangdong Province who were deployed to Hubei Province were surveyed with a self-designed device-related pressure injury questionnaire. Frequent distributions and logistic regression were used to identify factors associated with injury incidence and severity. In summary, 75.5% of nurses reported DRPI, and continuous use of personal protective equipment (PPE) on the head and neck was a major contributing factor to injury. While protective strategies such as adjusting for the size of the equipment, applying dressing, and washing the affected areas with warm water were reported, there were inconsistencies in their effectiveness. It was noted that each additional hour of PPE use increased the risk of developing DRPI by 52.5% (OR 1.53, 95% CI 1.10-2.12). The high incidence of DRPI among participants highlights the need for focused and comprehensive intervention strategies in future research. Though the findings suggest that it may be helpful to develop acute care settings-appropriate individualized assessment tools, multicenter studies will need to be conducted before a standardized assessment tool can be developed.
Noise in the clinical dental setting has been shown to exceed safe levels, and the risk to dental professionals, including occupational noise-induced hearing loss, is well-established. This pilot study investigated dentists' perceptions and experiences of the use of custom-made earplugs as a means of attending to the risk in the clinical dental setting. Dentists were recruited using convenience and purposive sampling and provided with custom-made attenuated earplugs, which were worn for a period of 12 weeks of usual clinical dental practice. Questionnaires were completed periodically. Data were analyzed statistically and thematically. There was a total of eight participants. Participants recognized the risk of hearing loss and supported the promotion and inclusion of hearing protection as a part of personal protective equipment. Participants noted an improved focus due to a reduction in noise perception. Disadvantages included discomfort and communication challenges. This pilot study assessed the process for, and feasibility of, conducting a larger-scale study and will contribute to the reliability and validity of such, which is recommended.
Measurements are considered to be the basis of exposure assessments used to determine risks to workers. Inhalation exposure poses the greatest risk for most airborne chemicals, and measurements are based on collecting (sampling) and analyzing air samples. Samplers have been developed for more than 120 years. Each new design has been intended to address flaws perceived in earlier designs. Users are faced with a varied array of samplers from which to choose. Comparisons are difficult to make because tests of sampler performance were not standardized until recently and have not been applied consistently. The existing large body of work does allow some conclusions to be drawn regarding performance. Many samplers have been shown to work effectively with test aerosols under controlled conditions in the laboratory. Further testing in the field has shown that not all samplers perform equally well in every situation; for example, under different wind speeds and directions or with aerosols that maintain unusual physical characteristics. There is not one aerosol sampler that can be used for all situations. Further, the design of a sampler and how the sampler needs to be handled can have an enormous influence on the result. Quality of manufacture, material of construction, cost, reusability, ease of use, setting of flow rates, transportation issues, and wearer acceptability all have an impact on selecting from among different samplers with similar performance. The range of available samplers constitutes a toolkit from which the most appropriate sampler could be selected for a given specific situation. Common inhalable and respirable aerosol samplers are considered in respect of their history of design and manufacture, validated performance studies, environmental factors, and practical use. However, the impact of these considerations on sampler selection is minimized through generalized industry-specific or task-specific recommendations. An online web-based Sampler Selection Tool is under development. It will use the information presented in this Commentary to provide a ranked list of appropriate samplers to be used in specific situations.
Environmental surface disinfection is a fundamental component of infection prevention and control (IPC) in healthcare settings. Sodium hypochlorite remains widely used owing to its broad-spectrum efficacy, availability, and low cost. Concerns regarding occupational health risks associated with chlorine spraying have led public health authorities to revise existing guidance. The World Health Organization currently recommends wiping as the preferred chlorine-based surface disinfection method. This policy revision was based on very low certainty evidence, and quantitative data directly comparing exposure risks between methods remain limited. This study quantified and compared occupational exposure to chlorine gas (Cl2) and ultrafine particles (UFPs) generated during surface disinfection with sodium hypochlorite applied by spraying versus wiping and assessed the influence of task duration and environmental conditions on cumulative exposure. Under controlled conditions, UFP and Cl2 emission factors (EFs) were measured, and a randomized crossover simulation was conducted to determine disinfection duration per method in a mock clinical room. A well-mixed room model estimated airborne concentrations and inhaled doses across 0.1 to 12 air changes per hour (ACH), including under high temperature, with organic load and soap-with-ammonia interaction. Mean UFP EFs were comparable between methods (spraying 3.1 × 108 and wiping 1.95 × 108 particles·min-1·m-2), while Cl2 concentrations remained below detection limits. Spraying was significantly faster (9.4 ± 3.0 vs. 25.0 ± 7.1 min; p < 0.001) and consistently resulted in lower cumulative exposure: at 0.2 ACH, wiping produced a 4.3-fold higher inhaled UFP dose. Across the 0.1 to 12 ACH range, spraying reduced the inhaled dose by 50 to 75% (p < 0.001). Although environmental factors exerted a stronger influence on absolute exposures, spraying consistently yielded lower Cl2 and UFP concentrations and inhaled doses. These findings indicate that cumulative inhalation exposure is driven primarily by environmental conditions, task duration, and ventilation, rather than the application method's intrinsic emission rate. Spraying shortened procedures consistently and reduced inhaled doses relative to wiping, supporting reconsideration of current IPC recommendations to incorporate duration-sensitive exposure-based assessments when selecting disinfection methods.
Loose-fitting powered air-purifying respirators (PAPRs) are widely used by healthcare workers to protect against inhalation hazards, as they require no fit testing. However, incorrect use can compromise their efficacy, which may progressively deteriorate over time. Therefore, there is a critical need for real-time monitoring of PAPR performance during occupational activities. In this study, a portable device called the Exposure Protection Integrated Communicator (EPIC) was developed, which uses optical particle sensors to evaluate the workplace protection provided by PAPRs. EPIC monitors concentrations inside and outside a respirator using two sensors to quantitatively calculate the protection factor (PF), defined as the ratio of particle concentrations outside to inside the respirator. The system applied algorithms to correct sensor readings and alert wearers if respirator protection was compromised. The prototype EPIC was evaluated using a manikin headform connected to a breathing recording and simulation system (BRSS) to simulate a sinusoidal breathing pattern. A PortaCount fit tester based on a single-condensation-nuclei-counter principle served as the reference measurement device during parallel tests. The results were expressed as PFs for comparison between the EPIC system and the reference method. The prototype EPIC demonstrated to be an effective tool for quantifying the real-time performance of PAPRs, particularly in environments with particle concentrations of 40,000 to 70,000 particles/L. Data collected from both the EPIC and PortaCount were compared, revealing that the EPIC could measure PFs ranging from 10 to 10,000. The EPIC showed a strong correlation with the reference PortaCount (R2 = 0.84), despite the two systems using different measurement principles and detection limits. The study results confirmed the effectiveness of EPIC in quantitatively assessing respirator particle ingress.
A functional understanding of human anatomy is fundamental for students studying health and medical sciences. Formalin, which is a formaldehyde-saturated solution, continues to be used for the preservation and disinfection of human specimens for teaching because other formalin substitutes are not readily available, practical, or preferred. The continued use of formalin exposes anatomy technicians who dissect human specimens to acute and chronic health effects, which has led to Australia's national government policy agency, Safe Work Australia, to pursue lower permitted airborne formaldehyde workplace exposure limits (WEL). During this study, 14 personal airborne samples were collected to calculate the geometric mean and 95th percentile of the formaldehyde 8-hr time-weighted average (8-hr TWA) and short-term exposure limit (STEL) for comparison to the current Australian WES and proposed Australian formaldehyde WELs. Three participants were recruited for the study and participated in formaldehyde air sampling and completed a questionnaire after each monitoring session to report formaldehyde exposure symptoms. The calculated 8-hr TWA and STEL geometric means were 1.1 and 1.4 ppm respectively, and the 95th percentile of both the 8-hr TWA and STEL exceeded the current Australian WES and proposed WELs. Questionnaire responses identified participants had experienced formaldehyde exposure symptoms related to itching eyes, inflamed eyes, headaches, and discomfort during dissection. Lower formaldehyde concentrations were identified during dissection in a dedicated dissection room where a partially effective dissection table with downdraft local exhaust ventilation and a laboratory fume hood were utilized, compared to teaching rooms with no local exhaust ventilation system. Formalin use continues to remain an occupational hazard for anatomy technicians who perform dissection, and careful attention is required toward implementing effective control measures such as substituting formalin with other suitable solutions, reducing formalin concentrations in embalming solutions, installing local exhaust ventilation systems, and using suitable personal protective equipment.
The filter used in an N95 filtering facepiece respirator (FFR) has a collection efficiency and pressure drop that are primarily influenced by filter depth and solidity, as well as the average diameter and electrostatic charge of its fibers. A sensitivity analysis was performed to determine the influence of each property on particle collection efficiency at the most penetrating particle size (MPPS) and pressure drop using previously verified N95 FFR filter performance models. Collection efficiency was most influenced by changes in filter solidity and least influenced by fiber charge. Likewise, pressure drop was most influenced by fiber diameter, least influenced by changes in filter depth, and was not affected by fiber charge. Given the competing desire for low pressure drop and high collection efficiency, the use of a quality factor demonstrated that increasing filter charge and fiber diameter had a nearly equal positive association with overall filter efficacy. A filter optimization process was also conducted that employed a non-linear optimization routine to first determine the filter depth required to obtain a collection efficiency criterion of ≥ 95% collection efficiency at the MPPS for sets of fiber diameter and filter solidity values, and to determine the pressure drop resulting from each combination of the three property values while holding fiber charge constant. This analysis demonstrated that filters with low solidity, high fiber diameter, and high depth produce the lowest pressure drop. However, all combinations of filter properties within the ranges analyzed produced acceptable pressure drops, indicating that an upper limit on filter depth can be applied based on N95 FFR design constraints and still maintain a reasonable pressure drop. To aid filter design efforts, linear regression models were developed to first predict the filter depth needed to meet the efficiency criterion given known fiber diameter and filter solidity, and then to predict the pressure drop from those three properties.
This manuscript describes the technical components and performance of a custom whole-body vibration (WBV) instrumentation system designed for autonomous, prolonged field measurement. The study demonstrated the technical readiness of the system's accelerometers. The system integrates a Teensy 4.1 microcontroller, triaxial microelectromechanical system accelerometers, force sensing resistors, global positioning system module, and microSD data storage. The accelerometers were validated against reference accelerometers commonly used in field-based WBV measurement using a motion simulator programmed with complex vibration input profiles specified in ISO 7096:2020 Earth-Moving Machinery-Laboratory Evaluation of Operator Seat Vibration for testing operator seat vibration in earth moving machinery. In the time domain, accelerometers in the custom WBV instrumentation system exhibited ≤ 2.21% error in root-mean-square (RMS) amplitude measurements and < 0.03 g sample-to-sample RMS deviation from the reference accelerometers. Frequency-domain analysis (1/3-octave band) suggested slight underestimation of signal power at low frequencies (≤10 Hz), but the differences were practically small at each 1/3-octave band. Ultimately, the system will enable WBV monitoring in settings in which operators are remote and/or the schedule of machine operation is variable (e.g., agriculture). Future work will focus on real-world validation and exploring use of the force sensing resistors to characterize operator posture, further enhancing the system's utility in occupational WBV exposure monitoring.
The ASTM D8445-22a Standard Practice for Measuring Chemical Emissions from Spray Polyurethane Foam (SPF) Insulation Samples in a Large-scale Ventilated Enclosure establishes procedures for measuring chemical emissions of volatile and semi-volatile organic compounds (VOCs and SVOCs) from spray polyurethane foam (SPF) insulation samples. This standard practice can be used to identify chemical emissions during SPF application and for three days following application. The goal of the D8445-22a is to generate chemical emissions data that can be used for research activities, modeled, and/or used as a basis for recommending reentry and re-occupancy times following the application of SPF in residential or commercial buildings. Potential reentry and re-occupancy times only apply to applications that meet the manufacturer's guidelines and are specific to the tested formulation. The purpose of the study was to demonstrate how data collected in accordance with the ASTM standard practice may be used by health professionals to recommend a time for unprotected trade workers to be restricted from entry into affected work areas following SPF application. Chemical emissions from two generic, high-pressure, open-cell formulations were evaluated in a ventilated enclosure. One SPF formulation contained emissive catalysts, and the other formulation, non-emissive catalysts. Exhaust ventilation was supplied to the enclosure at a rate of 10 Air Changes per Hour (ACH) for 2 hr during and post SPF application. The air change rate was then lowered to 0.3 ACH for the remainder of the test period. Chemical components selected for evaluation represent those typically present in SPF formulations and include methylene diphenyl diisocyanate (MDI), amine catalyst, aldehydes, and flame retardant.
Improvements in lithium-ion battery (LIB) safety rely on understanding the thermal runaway failure of the cells. Thermal abuse tests are done on LIBs to study their exothermic reaction kinetics and gaseous hazards. Typically, testing is conducted in either pressure vessels or accelerating rate calorimetry (ARC) systems. These experimental systems are often used with little cleaning between tests, raising questions about whether the accumulated or adhered vented products pose respiratory and other health concerns. Also, the guidelines on personal protective equipment (PPE) for researchers often do not specifically address hazards associated with LIB thermal abuse tests. There is a relative lack of data on what species might be re-emitted from these experimental systems and how standard PPE reduces exposure to any off-gassed species. To help answer some of these questions, this paper characterized gas emissions from a vessel containing LIB residue post-thermal runaway, detecting species including electrolyte solvents, dimethylcyclosiloxanes, and other low-volatility organic compounds. The most abundant species were ethylene carbonate (39 ppb) and propylene carbonate (34 ppb). None of the species concentrations from this well-ventilated vessel posed acute toxicity, but repeated exposure may result in chronic health impacts. Fabric samples from clothes exposed to the vessel headspace re-emit the adsorbed gases, which extends the duration of inhalation exposure for individuals. The low volatility of the species was further supported by partition coefficient values above one, indicating their persistence and dermal exposure risks. Respirator effectiveness against gases evolved from LIB residue was investigated. Suggestions on improving worker safety were given based on the results of this paper.
The National Academy of Sciences (NAS) Biological Effects of Atomic Radiation Committee (BEAR), particularly the BEAR I Genetics Panel, committed scientific misconduct by misrepresenting their research record in a 1956 publication in the journal Science to hide apparent massive disagreements amongst Panelists on population-based mutation risk estimates to achieve their ideological goals. While this circumstance has now been well documented, the present paper shows that Panel concerns over massive disagreements were misplaced as the Panelists misinterpreted mutation estimates and confused risk assessment concepts. This paper shows for the first time that their concerns with massive absolute Panelist disagreements over radiation-induced mutation rates across diverse species (i.e., bacteria vs. mammalian/insect species) and procedures disappeared when normalized within a doubling dose framework, which was well known to them. The Panel's decision to commit scientific misconduct (i.e., alter the research record by excluding widely divergent absolute mutation estimates, most notably from Milisav Demerec) was therefore not necessary to ensure support for their ideologically based LNT policy recommendations. Ironically, their ethical misconduct, which has damaged the reputation of the US NAS and their individual reputations, was not needed for the Panel to achieve its ideological goals. Finally, while the doubling dose offered an apparent convenient vehicle for hereditary risk assessment, this concept has numerous limitations that have restricted some of its risk assessment applications.
Pollutants in smoke from wildland and wildland urban interface (WUI) fires present an increasing risk to outdoor workers, field technicians, and others as the frequency and severity of these fires increase due to expansion of the WUI, changing land management practices, and climate change. Recent advancements have improved our understanding and ability to track and model wildfires, smoke plume chemistry, and associated health impacts. There are indications that smoke from burning certain fuels, including artificial materials present in many WUI fires and other biomass burned under certain conditions, may present enhanced health risks relative to smoke from typical biomass-only fires. However, large uncertainties, data gaps, and a lack of integration of available tools and datasets present substantial challenges in making recommendations and developing guidance to protect outdoor workers. Notwithstanding these uncertainties and data gaps, outdoor workers are exposed to potentially harmful wildfire pollutants with limited health protection guidance. There is a pressing need to advance the understanding of the relative risk of wildfire smoke based on the burned fuel and to provide tools to support real-time decision-making to protect the health of outdoor workers. Therefore, researchers and health professionals need to fill data gaps and develop integrated tools to provide decision-makers with clear guidance. This new guidance should be action-oriented, reflect current knowledge, and highlight remaining uncertainties. With these resources, decision makers can better strategize when and where outdoor work needs to be done to best protect those doing the work.
Hermann J. Muller, Nobel Prize recipient for producing gene mutations, was the de facto leader of the radiation genetics community from the mid-1920s until he died in 1967. Muller had a major impact on US hereditary/cancer risk assessment policies/practices, and the course of the secondary school biological sciences curriculum development in the US and worldwide. Despite these accomplishments, Muller was at the center of provocative controversies. Within this context, this paper reports the discovery of a letter (April 4, 1956) from Muller to Warren Weaver, Chair of the BEAR I Genetics Panel, about a major controversy in which the radiation-induced hereditary damage estimates of Panelist Milisav Demerec were strikingly lower than those of others, especially Muller's. In this recently discovered letter, Muller attempted to reconcile these differences and unexpectedly claimed that Demerec's estimates were correct. However, Muller appears to have inexplicably confused the evaluation by switching his focus away from Demerec's data on radiation-induced mutation rates in bacteria to his old unresolved dispute with Demerec regarding fruit flies. He even suggested that Demerec was correct in that Muller's groundbreaking mutational research had induced mostly major chromosomal aberrations rather than gene mutations. Muller curiously suggested that he had thereby resolved the conflict amongst Demerec, himself, and other BEAR I Genetics Panel members. Yet, as noted, Demerec's data for the BEAR I Genetics Panel mutation risk estimates were based on his (i.e., Demerec's) more current research on bacteria, with Muller completely missing the entire point of the Panel's scientific conflict with the Demerec data. Thus, Muller never addressed the real issue. This transitory detachment from factual reality by Muller is obvious and acute. Finally, if Weaver had shared this letter from Muller with the BEAR I Genetics Panel, it seems possible that many members might have been so troubled by Muller's apparent detachment from reality (on such a consequential disagreement) that they would have questioned why they had allowed Muller to exert so much influence on their report.
This pilot research assessed the reliability of wet-bulb globe temperature (WBGT) screening tools and examined how different microenvironments might affect worker-level WBGT in Taiwanese agriculture. In July 2024, WBGT was recorded at six locations using a QUESTemp monitor with sensors positioned at the head, abdomen, and ankle (weighted 1:2:1), along with portable Kestrel and AZ (AZ) devices and the AIHA® app. The AZ devices were evaluated for within-site variations across various work environments, including soil, shade, ground-cover cloth, grassland, asphalt, and ridges. Agreement analyses and Bland-Altman plots were used to compare methods. Median WBGT values ranged in the low to mid-30s°C, with four sites having 50% or more of measurements at or above 32 °C. The Kestrel device demonstrated the closest agreement (bias +0.32 °C; RMSE 0.80 °C), the AZ device tended to underestimate (-0.94 °C; RMSE 1.28 °C), and the AIHA app showed the largest errors (bias -0.83 °C; RMSE 1.82 °C). Microenvironmental factors caused WBGT shifts between -1.25 and +2.87 °C, with decreases caused by working in shaded areas and increases caused by working in reflective ground covers. When screened against the operational WBGT benchmarks (30 °C and 32 °C), the QUESTemp monitor frequently recorded values at or above these thresholds, indicating high-heat conditions. However, the systematic underestimation by the wearable AZ device resulted in a significantly lower detection rate of the high-heat conditions, highlighting the risk of false-negative safety assessments when using uncorrected personal monitors. Overall, the portable/wearable Kestrel and AZ devices showed closer agreement with the QUEST than the weather-station-based app estimates. Given the limitations of regional weather data observed in this pilot study, effective heat-risk management in agriculture requires site-specific monitoring to account for microenvironmental variations, rather than relying solely on app-based estimates.
