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Ethylene Oxide (EtO) is a colorless, flammable gas at room temperature, produced by the catalytic oxidation of ethylene. EtO is widely used by medical sterilization facilities to clean medical supplies and equipment. Recent epidemiological studies showed that EtO is a more potent carcinogen than previously documented, leading the Environmental Protection Agency (EPA) to update, in December 2016, the inhalation unit risk estimate for EtO. This resulted in the identification of EtO as a potential health concern in several areas across the US, including the state of Utah. The geography surrounding Salt Lake Valley creates a bowl; ideal for collecting air pollution emissions. The region often experiences inversion episodes which inhibit vertical mixing and cause an accumulation of air pollutants, leading to unhealthy pollution levels. Using the EPA's dispersion modeling software, AERMOD, this study estimated EtO concentrations through facility stack and fugitive emissions modeling results. These values were compared with those of canister-based concentrations from ambient air samples taken near a medical device sterilization facility in the Salt Lake Valley. Stainless steel, whole-air passivated canisters were used to collect 24-hour ambient concentration samples of EtO. Eight locations surrounding a Salt Lake Valley medical device sterilization facility and four background sites were chosen to measure the ambient concentrations. Accounting for potential atmospheric impacts on EtO, measurements were sampled in winter 2022 (January-March) and summer 2022 (July-September). The modeled EtO concentrations were adjusted to account for background values associated with the winter or summer data. Then the two methodologies were compared using a Wilcoxon Sign-ranked, paired test. The statistical analysis resulted in six of the eight sample locations surrounding the sterilization facility being significantly different when comparing canister-based measurements of ambient EtO to modeled estimates. Canister-based measurements taken at sites one, three, and four were statistically greater than the modeled estimates, while sites two, five, and seven were statistically less than the modeled estimates. Also, the summer background value calculated was almost 2.5 times greater than the winter. The results do not suggest whether one method is more or less conservative than the other. In conclusion, the five of the closest sites and site seven were statistically different when comparing measured and modeled ambient concentrations of EtO. The comparison results do not clearly indicate if a correction factor could be derived for future human exposure to cancer risk assessment modeling. However, it is reasonable that the closer to the sterilization facility, the more total EtO exposure will be realized.

Ultrafine particulate (UFP) matter exposures are associated with negative health outcomes. UFPs (

Indoor Air Quality (IAQ) has been an area of growing concern with the increasing knowledge of health hazards associated with contaminants, particularly in high occupancy buildings where residents may be exposed to high levels of nuisance dust and other contaminants. Leadership and Energy in Environmental Design (LEED®) certification, which is awarded to buildings that prioritize sustainability and efficient resource use, has been increasingly sought in new construction. As LEED-certified buildings become more commonplace, it is worthwhile to consider whether these new building practices improve IAQ for its occupants. This study compares particulate matter (PM) concentrations in 12 LEED-certified buildings to 12 analogous non-LEED certified buildings on the University of Utah campus. Real-time air sampling was conducted in each building for PM measurements and a Wilcoxon signed rank test was conducted to compare PM levels. A statistically significant difference was found between LEED certification and PM concentrations, with LEED-certified buildings containing, on average, approximately half the PM of their non-LEED counterparts. These findings suggest that LEED certification is worth the financial investment, as it may lead to improved IAQ for residents. However, further research on other contaminants is warranted, including the characterization and comparison of formaldehyde and carbon dioxide levels.

Wipe sampling is a commonly used method for testing a surface for beryllium or other metal particle contamination. Existing wipe sampling methods have only been validated for smooth surfaces. On rough surfaces contaminant particles may be located behind surface projections where they would not be collected by the wipe. This could lead to an underestimate of surface contamination levels. Worker exposure to surfaces contaminated with beryllium could contribute to beryllium sensitization leading to chronic beryllium disease. Likewise, exposure to surfaces contaminated with other toxic metals could have their own health effects. This study investigated the efficiency of collecting 1–5 μm diameter zinc oxide particles by five commercially available wipe materials (SKC Smear Tabs, Whatman® 41 filter paper, Kimtech Prep* ScottPure* Critical Task Wipers, Ghost Wipes, and Hygenall LeadOff wipes) from surfaces of different roughness (sandpaper of 60–6,000 grit). Zinc oxide was used as a surrogate for beryllium because of its much lower toxicity. Overall, the wipes were most efficient at collecting particles from the fine grits and poor at collecting particles from the coarse grits. The Smear Tabs and Whatman filters performed poorly in both durability and particle collection efficiency. In both respects, the superior performers were the Ghost Wipes and LeadOff wipes. However, even in the best case, the wipe still left behind 20% of the particles. These results indicate that underestimating metal particle contamination levels is a serious possibility when conducting wipe sampling on textured surfaces.

Native Americans have experienced a long history of environmental injustice, including natural resource exploitation and commercial activity with environmental impacts. A community-based participatory research (CBPR) approach was used to partner with two Rocky Mountain West reservations to conduct pilot-level assessments of potential soil contamination by heavy metals. The Community Advisory Board in conjunction with the research team selected residential areas and community sites for sampling. Samples were obtained, transported to a laboratory for dehydration and sieving, and were analyzed with a handheld X-ray fluorescence (XRF) tool for the presence of 24 heavy metals. Heavy metals concentrations were compared between reservations and were found to be statistically different from one another. Findings were also compared to levels recommended by the Environmental Protection Agency (EPA) and World Health Organization (WHO) to determine possible hazards to human health. Concentration of Sr, Rb, and Th were well above acceptable EPA levels and require further analysis. High localized Pb levels were found in one area, while Hg levels were found close to EPA standards. CBPR was essential to understanding preliminary contamination patterns. In conclusion, even reservations with similar geographies and histories present with unique contaminations and require individualized study to determine possible environmental mitigation.

Line cooks in commercial restaurants work intense, high-stress shifts during near sources of heat, rendering them vulnerable to heat stress and occupational injury. However, there is a dearth of literature on heat stress among this population. This study investigated three common commercial kitchen configurations—zone, island, and assembly—to determine which design experiences the highest temperatures and if temperatures were in excess of recommended levels. A total of 11 restaurants were sampled for temperature using a Wet Bulb Globe Thermometer (WBGT). Descriptive statistics indicated that, on average, zone configurations are hotter than other kitchens and could pose a risk of heat stress; however, a Kruskal-Wallis test of significance revealed that this distinction was not statistically significant. Two measurements for zone kitchens were borderline significant, suggesting that future studies with greater statistical power would find significant differences between the kitchen types and further illuminate the risk of heat stress.

Native American populations face considerable health disparities, especially among those who live on reservations, where access to healthcare, education, and safe housing can be limited. Previous research on tribal housing has raised concerns about housing construction, damage, and possible linkage to adverse health effects (e.g., asthma). This community-based participatory research (CBPR) project investigated indoor air quality issues on two Rocky Mountain west reservations. At the onset of the project, the research team formed a partnership with community advisory boards (CABs) consisting of representatives from tribal councils and community members. Research design, implementation, and dissemination all took place in full collaboration with the CABs following approval through official tribal resolutions. Residential homes were monitored for particulate matter with diameter 2.5) and radon concentrations. Low-cost air quality sensors and activated charcoal radon test kits were placed in tribal households for 6-8 days. A large amount of data were below the sensor limit of quantification (LOQ), but several homes had daily averages that exceeded suggested PM2.5 guidelines, suggestive of the potential for high exposure. Additionally, nearly half of all homes sampled had radon levels above the EPA action level, with mitigation activities initiated for the most concerning homes. Findings from this study indicate the need for future community-wide assessments to determine the magnitude and patterns of indoor air quality issues.

The present study provides a thermodynamic degradation approach to model human stress response. Finger skin temperature was used as an indicator of stress response to a stressor (or stressful event) followed by a recovery. The entropy change (ΔS) is calculated using heat transfer (δQ) from the peripheral skin and finger skin temperature (Tf). It was hypothesized that the human stress response, as evidenced by finger skin temperature change, is a quasi-static process. The entropy approach is demonstrated using data from a medical school experimental study. The finger skin temperature was measured under three conditions (relaxation, stressor task, and recovery) during the physiological test profile. The entropy change (ΔS) is postulated as entropy damage (ΔSD), which is a metric for measuring the aging or system degradation. The aging-ratio, Aaging-ratio, that is, the ratio of entropy change due to stressor to that of recovery, is presented for both male and female subjects. The statistical t-tests demonstrate statistical significance in human stress response to stressor and recovery states within and between male and female subjects. This novel approach could be valuable to medical researchers, particularly in the field of occupational health to evaluate human exposure to stressful environments.

The Great Salt Lake has been gradually desiccating, increasing the amount of exposed lakebed and potentially exposing heavy metals that may be present in the lakebed soil and sediments. It is hypothesized that there is a statistically significant difference between the current and previous shorelines, with the highest concentrations being at the current shoreline. This study used systematic sampling to collect 32 samples from the current shoreline and previous shorelines (elevation of 1281 and 1282 m, respectively) for a total of 64 samples. All samples underwent X-ray fluorescence analysis to quantify heavy metal concentrations. Nearly all samples contained arsenic (highest concentrations near the current shoreline). The majority of samples (80%) showed mercury levels below the limit of detection (LOD). A statistically significant difference in heavy metal concentrations between the two locations for arsenic, zinc, iron, manganese, rubidium, zirconium, and strontium was found. In addition, it was...

The machining of axle hub flange housings manufactured using G10530 steel is described in this paper. The machining of axle hub flange housings can lead to the entanglement of chips around workpiece holding fixtures, which leads to a loss of productivity due to the interruption of the machining process to remove entangled machining chips in the vicinity of the chuck (chip crowding). The finite element (FE) method was used to predict machining characteristics in order to eliminate the phenomenon of ‘chip crowding’ around rotating machine parts that impede the effective machining of axle hub flange housings. The finite element method is compared to traditional analytical calculations to observe whether discrete computations can accurately predict machining characteristics and to visually predict the shape of chips to eliminate the possibility of ‘chip crowding’. From this study, it is shown that short chips can be created using variable cutting speeds and that the FE method can be used to analyze chip formations in order to optimize the turning of G10530 axle hub flange housings. For the current practice of machining axle hub housings, when fedge/tr = 0.25 (small cutting edge radius), the level of power required for chip formation is calculated to be 6400 W generating a maximum temperature at the onset of chip formation of ~563 °C, and when fedge/tr = 0.75 (large cutting edge radius), the level of power required for chip formation is calculated to be 3200 W generating a maximum temperature at the onset of chip formation of ~292 °C. When forming chips at variable cutting speeds, the best case condition is one that draws the least power and generates the lowest temperature at the chip tool interface. This is achieved when a large cutting edge radius tool (fedge/tr = 0.75) is used for machining axle hub flanges. Closed form solutions appear to describe the machining conditions at the steady-state conditions very accurately. However, the FE method tends to generate accurate values under the conditions of unsteady chip formation when cutting at variable speeds. The innovations presented in this paper are associated with providing the necessary information to machine axle hub flanges with variable cutting speeds that eliminate the occurrence of ‘chip crowding’ by naturally fragmenting the formation of long metal chips.

An ideal inhalable aerosol sampler for occupational exposure monitoring would have a sampling efficiency that perfectly matches the inhalable particulate matter (IPM) criterion. Two common aerosol samplers in use worldwide are the closed-face cassette (CFC) and the Institute of Occupational Medicine (IOM) sampler. However, the CFC is known to under-sample, with near zero sampling efficiency for particles30 µm, whereas the IOM, considered by many to be the "gold standard" in inhalable samplers, has been shown to over-sample particles60 µm. A new sampler in development incorporates characteristics of both the CFC and the IOM. Like the CFC, it would be disposable, have a simple design, and is intended to be oriented at a 45° downward angle. Like the IOM, the new sampler has a 15-mm inlet diameter and incorporates a 25-mm filter cassette with a protruding lip. The IOM is oriented at 0° to the horizontal, so it is hypothesized that orienting the new sampler at ∼45° downward angle will reduce oversampling of larger particles. In comparison, the CFC's inlet diameter is 4 mm; increasing the size of the inlet should allow the new sampler to have an increased efficiency relative to the CFC for all particles. A unique characteristic of the new sampler is the incorporation of a one-piece capsule-style filter that mimics the IOM's cassette but is made of disposable material. Seven different sizes of alumina particles (mean aerodynamic diameters from 4.9-62.4 µm) were tested (total = 124 samples collected). For each test, six samplers were placed on a manikin located inside a wind tunnel operated at 0.2 m/sec. Results indicated that the new sampler improved on the CFC for smaller particles, providing a larger range for which it matches the IPM criterion, up to 44.3 µm. However, the efficiency was significantly lower in comparison to the IPM criterion for particle sizes above 60 µm. Overall, the new sampler showed promise, but additional modifications may help improve sampling efficiency for larger particles.

Traditional machining processes, where material is removed by a cutting tool from a workpiece, can introduce residual stresses at the surface of machined pieces. This paper provides an examination of an alternative machining methodology called modulated tool path machining. The ultimate objective of this research is to determine the effects of modulated tooling path machining processes, as applied to control chip geometry, on the surface stress of selected materials. Residual stresses in machined samples were characterised through the use of X-ray diffraction by comparing the modulated path method with a more traditional material removal technique (i.e. constant surface speed and constant contact).This paper is part of a Themed Issue on Measurement, modelling and mitigation of residual stress.

The paper presents a novel approach involving the use of Maxwell relations to combine multiple physiological measures to provide a measure of entropy change. The physiological measures included blood pressure (BP), heart rate (HR), skin temperature (ST), electromyogram (EMG), and electrodermal response (EDR). The multiple time-series physiological data were collected from eight subjects in an experimental pilot study conducted at the Human Engineering Laboratory of NASA Langley Research Center. The methodology included data collection during a relaxation period of eighteen minutes followed by a sixty-minute cognitive task. Two types of entropy change were computed: (a) entropy change (ΔSBP) due to blood pressure, heart rate, and skin temperature and (b) entropy change (ΔSEMG) due to electromyogram, electrodermal response, and skin temperature. The results demonstrate that entropy change provides a valuable composite measure of individual physiological response to various stressors that could be valuable in the areas of medical research, diagnosis, and clinical practice.

A newly designed, low-cost, disposable inhalable aerosol sampler was developed to assess workers personal exposure to inhalable particles. This sampler was originally designed to operate at 10 L/min to increase sample mass and, therefore, improve analytical detection limits for filter-based methods. Computational fluid dynamics modeling revealed that sampler performance (relative to aerosol inhalability criteria) would not differ substantially at sampler flows of 2 and 10 L/min. With this in mind, the newly designed inhalable aerosol sampler was tested in a wind tunnel, simultaneously, at flows of 2 and 10 L/min flow. A mannequin was equipped with 6 sampler/pump assemblies (three pumps operated at 2 L/min and three pumps at 10 L/min) inside a wind tunnel, operated at 0.2 m/s, which has been shown to be a typical indoor workplace wind speed. In separate tests, four different particle sizes were injected to determine if the sampler's performance with the new 10 L/min flow rate significantly differed to that at 2 L/min. A comparison between inhalable mass concentrations using a Wilcoxon signed rank test found no significant difference in the concentration of particles sampled at 10 and 2 L/min for all particle sizes tested. Our results suggest that this new aerosol sampler is a versatile tool that can improve exposure assessment capabilities for the practicing industrial hygienist by improving the limit of detection and allowing for shorting sampling times.

INTRODUCTION Americans spend the majority of their time indoors where levels of pollutants may run two to five times—and occasionally more than 100 times—higher than outdoor levels [1]. Many of these pollutants can cause adverse health reactions in building occupants, which can contribute to lower worker productivity and increased sick leave. Traditional methods of indoor pollutant control in sealed buildings involve the use of outdoor ventilation. Outdoor ventilation requires the intake of outdoor air, which must be heated or cooled to meet indoor temperature and humidity requirements. This represents between 10–20% of the total energy consumption of a building [2]. Even though past research has touched on incorporating actual biofiltration into building systems, there is little to no research on the incorporation of biofilters into energy-efficient residential dwellings. One of the first applications of biofiltration for energy-efficient homes was conceived close to 30 years ago [3]. Figure 1 shows an e...

The manufacture of stringed instruments has strong elements of traditional practice, particularly in the choice of materials from which the instruments are made. While man-made materials have been used in successful instruments, they are overwhelmingly made of wood. The preferred species include Sitka spruce, mahogany, rosewood and maple. Furthermore, the grade of materials used for instruments is extremely high, only one step below that used for the load-carrying structures of aircraft. The ideal piece of wood is straight-grained and without imperfections such as knots, checks or discolouration. The growth rings should be close together, so slow-growing trees are preferred. The result is that trees yielding instrument-quality wood have been heavily logged and are becoming very scarce. This is reflected in the rising prices of instrument grade wood. At this writing, a master-grade top blank for a single acoustic guitar can cost up to $300. The retail value of guitars sold in the USA is approaching $1 billion per year, so the demand for materials is not going to ease soon. Clearly, the industry must change its practices if it is to sustain production. Several fundamental changes are required. The strong prejudice against laminated materials must be overcome. High grade plywood exhibits structural properties and uniformity that would make it ideal for instrument manufacture, but its use is limited to student grade instruments. The Convention on International Trade and Endangered Species (CITES) outlines the terms under which traditional species can be legally and sustainably harvested, but it limits production volumes and the temptation to skirt the regulations is strong. Thus, another required change is to switch to fast-growing species. Finally, manufacturing processes must be modified and life cycle management procedures should be implemented to allow for the effective and efficient use of smaller, younger trees.

With increased scope and activity of the nanotechnology industry, there is a need for greater understanding about filter collection performance and efficiency. Filtration is a process which is used to control the particulate fluxes in exhaust streams throughout various manufacturing and laboratory processes. Filtration becomes a key factor in effective ventilation system design, particularly in relation to environmental and health concerns. The purpose of this paper is to explore filtration theory and techniques, summarise the various filter types employed, and illustrate the effectiveness for reducing particulate emissions during the machining process.