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Poás Volcano made a magmatic eruption in April 2017. The volcanic outburst resulted in an ash and vapor column towering over three kilometers high. Since that time, there has been a continual release of gases, aerosols, and more recently, ash, posing potential issues for visitors and park rangers. In this work, the potential for exposure to acid gases and aerosols faced by park rangers, officials, and visitors to the Poás Volcano National Park was evaluated, and the concentrations found were compared with the exposure limits established by the Occupational Safety and Health Administration (OSHA). The study was conducted between October 2021 and November 2022. the concentrations of HCl(g), HNO3(ac), HF(g), and H2SO4(ac) were determined at three strategic points: the ranger station, the visitor center, and the main crater viewpoint. The maximum concentrations obtained were (7.0 ± 1.6) ppb for HCl(g), (6.2 ± 2.8) ppb for HNO3(ac), and (0.029 ± 0.044) ppm for H2SO4(ac). There were no concentration values above the detection limit (0.94 μg/m3) for HF(g). By comparing the data obtained with similar studies, it is concluded that the measured values in Poás Volcano National Park are low and only show similarities to the results found in volcanoes within the national territory. The exposure limit established by OSHA (0.02 ppm) was only surpassed by H2SO4(ac), and could be the cause of health effects experienced over the years by park rangers. To minimize these risks, the use of personal protective equipment and air quality monitoring is essential. [ABSTRACT FROM AUTHOR]

The Partner Agencies of the International Space Station (ISS) maintain separate career exposure limits and shared Flight Rules that control the ionising radiation exposures that crewmembers can experience due to ambient environments throughout their space missions. In low Earth orbit as well as further out in space, energetic ions referred to as galactic cosmic radiation (GCR) easily penetrate spacecraft and spacecraft contents and consequently are always present at low dose rates. Protons and electrons that are trapped in the Earth’s geomagnetic field are encountered intermittently, and a rare energetic solar particle event (SPE) may expose crew to (mostly) energetic protons. Space radiation protection goals are to optimize radiation exposures to maintain deleterious late effects at known and acceptable levels and to prevent any early effects that might compromise crew health and mission success. The conventional radiation protection metric effective dose provides a basic framework for limiting exposures associated with human spaceflight and can be communicated to all stakeholders. Additional metrics and uncertainty analyses are required to understand more completely and to convey nuanced information about potential impacts to an individual astronaut or to a space mission. Missions to remote destinations well beyond low Earth orbit (BLEO) are upcoming and bestow additional challenges that shape design and radiation protection needs. NASA has recently adopted a more permissive career exposure limit based upon effective dose and new restrictions on mission exposures imposed by nuclear technologies. This manuscript reviews the exposure limits that apply to the ISS crewmembers. This work was performed in collaboration with the advisory and guidance efforts of International Commission on Radiological Protection (ICRP) Task Group 115 and will be summarized in an upcoming ICRP Report.

The Partner Agencies of the International Space Station (ISS) maintain separate career exposure limits and shared Flight Rules that control the ionising radiation exposures that crewmembers can experience due to ambient environments throughout their space missions. In low Earth orbit as well as further out in space, energetic ions referred to as galactic cosmic radiation (GCR) easily penetrate spacecraft and spacecraft contents and consequently are always present at low dose rates. Protons and electrons that are trapped in the Earth's geomagnetic field are encountered intermittently, and a rare energetic solar particle event (SPE) may expose crew to (mostly) energetic protons. Space radiation protection goals are to optimize radiation exposures to maintain deleterious late effects at known and acceptable levels and to prevent any early effects that might compromise crew health and mission success. The conventional radiation protection metric effective dose provides a basic framework for limiting exposures associated with human spaceflight and can be communicated to all stakeholders. Additional metrics and uncertainty analyses are required to understand more completely and to convey nuanced information about potential impacts to an individual astronaut or to a space mission. Missions to remote destinations well beyond low Earth orbit (BLEO) are upcoming and bestow additional challenges that shape design and radiation protection needs. NASA has recently adopted a more permissive career exposure limit based upon effective dose and new restrictions on mission exposures imposed by nuclear technologies. This manuscript reviews the exposure limits that apply to the ISS crewmembers. This work was performed in collaboration with the advisory and guidance efforts of International Commission on Radiological Protection (ICRP) Task Group 115 and will be summarized in an upcoming ICRP Report. [ABSTRACT FROM AUTHOR]

The United States has witnessed a concerning surge in the incidence of diseases like Coal Workers' Pneumoconiosis (CWP), despite numerous efforts aimed at prevention. This study delves into the realm of respiratory health by investigating the deposition of dust particles within the respiratory tract and lungs. By analyzing particles of varying sizes, shapes, velocities, and aerodynamic diameters, we aim to gain a comprehensive understanding of their impact on deposition patterns. This insight could potentially drive changes in dust exposure protocols within mining environments and improve monitoring practices. The interplay of several critical factors, including particle characteristics and an individual's breathing patterns, plays a pivotal role in determining whether particles settle in the lungs or are exhaled. This paper provides a comprehensive literature review on Respirable Coal Mine Dust (RCMD), with a specific focus on examining particle deposition across different regions of the airway system and lungs. Additionally, we explore the utility of Computational Fluid Dynamics (CFD) in simulating particle behavior within the respiratory system. Predicting the precise behavior of dust particles within the respiratory airway poses a significant challenge. However, through numerical simulations, we aspire to enhance our understanding of strategies to mitigate total lung deposition by comprehensively modeling particle interactions within the respiratory system. [ABSTRACT FROM AUTHOR]

Abstract In the late-1990s, the FCC and ICNIRP adopted radiofrequency radiation (RFR) exposure limits to protect the public and workers from adverse effects of RFR. These limits were based on results from behavioral studies conducted in the 1980s involving 40–60-minute exposures in 5 monkeys and 8 rats, and then applying arbitrary safety factors to an apparent threshold specific absorption rate (SAR) of 4 W/kg. The limits were also based on two major assumptions: any biological effects were due to excessive tissue heating and no effects would occur below the putative threshold SAR, as well as twelve assumptions that were not specified by either the FCC or ICNIRP. In this paper, we show how the past 25 years of extensive research on RFR demonstrates that the assumptions underlying the FCC’s and ICNIRP’s exposure limits are invalid and continue to present a public health harm. Adverse effects observed at exposures below the assumed threshold SAR include non-thermal induction of reactive oxygen species, DNA damage, cardiomyopathy, carcinogenicity, sperm damage, and neurological effects, including electromagnetic hypersensitivity. Also, multiple human studies have found statistically significant associations between RFR exposure and increased brain and thyroid cancer risk. Yet, in 2020, and in light of the body of evidence reviewed in this article, the FCC and ICNIRP reaffirmed the same limits that were established in the 1990s. Consequently, these exposure limits, which are based on false suppositions, do not adequately protect workers, children, hypersensitive individuals, and the general population from short-term or long-term RFR exposures. Thus, urgently needed are health protective exposure limits for humans and the environment. These limits must be based on scientific evidence rather than on erroneous assumptions, especially given the increasing worldwide exposures of people and the environment to RFR, including novel forms of radiation from 5G telecommunications for which there are no adequate health effects studies.

Human milk is the healthiest option for newborns, although, under specific circumstances, infant formula is a precious alternative for feeding the baby. Except for the nutritional content, infant formulas and baby food must be pollutant-free. Thus, their composition is controlled by continuous monitoring and regulated by establishing upper limits and guideline values for safe exposure. Legislation differs worldwide, although there are standard policies and strategies for protecting vulnerable infants. This work presents current regulations and directives for restricting endocrine-disrupting chemicals and persistent organic pollutants in infant formulas. Risk assessment studies, which are limited, are necessary to depict exposure variations and assess the health risks for infants from dietary exposure to pollutants. [ABSTRACT FROM AUTHOR]

Of particular interest within fifth generation (5G) cellular networks are the typical levels of radiofrequency (RF) electromagnetic fields (EMFs) emitted by 'small cells', low-power base stations, which are installed such that both workers and members of the general public can come in close proximity with them. In this study, RF-EMF measurements were performed near two 5G New Radio (NR) base stations, one with an Advanced Antenna System (AAS) capable of beamforming and the other a traditional microcell. At various positions near the base stations, with distances ranging between 0.5 m and 100 m, both the worst-case and time-averaged field levels under maximized downlink traffic load were assessed. Moreover, from these measurements, estimates were made of the typical exposures for various cases involving users and non-users. Comparison to the maximum permissible exposure limits issued by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) resulted in maximum exposure ratios of 0.15 (occupational, at 0.5 m) and 0.68 (general public, at 1.3 m). The exposure of non-users was potentially much lower, depending on the activity of other users serviced by the base station and its beamforming capabilities: 5 to 30 times lower in the case of an AAS base station compared to barely lower to 30 times lower for a traditional antenna. [ABSTRACT FROM AUTHOR]

The verification of the limits of the population’s exposure to the magnetic field generated by double-circuit power lines from field measurements carried out on site is not trivial. It requires knowledge of the power line current instant values during the measurement period, the determination of the relationship between current and field at the measurement points (made more complex by the double-circuit overhead line configuration) and the use of that relationship to extrapolate the field values. Nevertheless, the verification of exposure limits for double-circuit power lines from on-site measurements is often conducted with rough, or not particularly stringent, procedures. A practical and straightforward procedure of general validity for non-optimized double-circuit lines is proposed here. No specific measurement position or conductors disposition knowledge is required as well as no complex three-dimensional finite element method code is necessary. The procedure, potentially also applicable to high- and extra-high-voltage lines, is validated on a medium-voltage (15 kV) double-circuit overhead power line study case. Exposure limits assessment suggests that if the line is operated at its rated capacity (230/285 A), the 3 μT quality target is missed. Results are provided with a 95% confidence interval ranging from ±100 nT to ±140 nT in all the cases.

Maximum power extrapolation techniques from measured data are usually employed to assess the compliance with standards of average fields radiated by base stations. However, such techniques provide an upper bound, which is not reached in real scenarios. This is particularly true in 5G Communications, where Active Antenna Systems allow a decrease of the average power density according to the adopted scheduling strategy. This paper is focused on the power reduction estimation in realistic scenarios. In particular a deterministic model of a communication system is used to obtain simple formulas only requiring the knowledge of the served area angular extension and of the Envelope Radiation Pattern of the antenna. The model, developed for beam steering and grid of beams antennas, is also extended to analyze the case of Multi User massive Multiple Input Multiple Output (MU-mMIMO) antennas with single layer per user, showing that under proper hypothesis on the beams of the antenna it is possible to estimate the reduction parameter without the explicit knowledge of the number of layers of MU-mMIMO systems. In spite of the simplicity of the approach, comparison with stochastic models and results reported in recent literature show that the formulas obtained using the model proposed in this paper allow to obtain a useful approximation of the power reduction factor, making the formulas suitable for a preliminary fast estimation of the Electromagnetic Field in 5G cells for human exposure assessment.

In this contribution, we focus on the exposure limits and compliance distances of 5G communication systems based on large antenna arrays with high gain and multiplexing capability. In particular, starting from the observation that the antenna array continuously changes its radiation pattern to communicate with a number of user terminals, we develop a simple approach for evaluating a reliable but not overly conservative boundary for the fields radiated by the antenna array. This approach is based on the use of the Normalized Average Power Pattern, and through the paper we show its behavior and demonstrate its usefulness in some cases of interest. Finally, the obtained results are validated by means of an electromagnetic simulation of the antenna and the propagation scenario, that is achieved by means of a ray-launching code.

This study examines thermal responses of skin to pulsed millimeter wave (mm-wave) and radiofrequency (RF) radiation. We review limits for pulse fluence in the IEEE Std. C95.1-2019 and the 2020 guideline of the International Commission on Nonionizing Radiation Protection (ICNIRP), as well as the recently re-affirmed guidelines of the U.S. Federal Communications Commission (FCC). The focus of the study is on millimeter-wave frequencies (30-300 GHz) where energy is absorbed close to the body surface and intense pulses could potentially cause high temperature gradients at the skin, but the model is extended to lower frequencies as well. The study employs a simple one-dimensional baseline thermal model for skin and Pennes' bioheat equation (BHTE), together with a baseline model for thermal damage to skin based on a standard model. The predicted temperature increases produced by 3-sec pulses at 94 GHz are consistent with previous experimental results with no adjustable parameters in the model. The few reported data on thermal damage to the skin from pulsed 94 GHz energy are insufficient to enable a conventional analysis of damage thresholds and the data may be affected by errors in dosimetry. The baseline model suggests that the implicit limits on pulse fluence in the present FCC guidelines might allow, in extreme (but in practice unrealistic) cases, transient increases in skin temperature that approach thresholds for thermal pain but which remain well below levels anticipated to cause thermal damage. Limits on pulse fluence in the current IEEE and ICNIRP exposure guidelines would preclude such effects. Such extreme pulses are far above those that are emitted by wireless and other technologies but may be emitted by some nonlethal weapons systems. FCC's proposed “device-based time averaging” rules will restrict thermal transients in skin from mm-wave transmitters to levels that are roughly an order of magnitude below the slower temperature increases produced by the low-frequency components of the modulation waveform and appear to be excessively conservative. An appendix discusses the applicability of two approximations to the analytical solutions to the bioheat equation that can be used to estimate temperature increases in skin from exposure to mm-waves.

This paper considers the problem of choosing an appropriate “averaging time” in radiofrequency (RF) exposure limits to protect against thermal hazards, focusing on the RF frequency range above 3-10 GHz. Analysis is based on examination of the dynamic properties of thermal models for tissue using Pennes' bioheat equation. Three models are considered: a baseline model consisting of a uniform half space with dielectric and thermal properties similar to those of human skin with adiabatic boundary conditions; a layered 1D model with dielectric and thermal properties similar to those of skin, fat, and underlying muscle, with convective boundary conditions appropriate for room environments; and exposures to the head of an anatomically detailed image-based model (“Taro”). RF exposure consisted of plane wave radiation incident on the two planar models, and radiation from resonant dipoles located 1.5 cm from the head model, at frequencies ranging from 1 to 300 GHz. The dynamic properties of the models were explored by analytic solution of the baseline model, and from numerical solutions of the thermal responses of the layered and head models. From the step responses of the models (increases in surface temperature to a suddenly imposed exposure), the impulse and frequency responses of the models were obtained. In the frequency domain, the thermal models exhibit extreme lowpass characteristics with cutoff (-3 dB response) frequencies below 1 mHz. The impulse response to millimeter wave radiation (30-300 GHz) shows a sharp peak at zero time, due to short term accumulation of heat near the surface, which dissipates quickly as heat is conducted into deeper layers of tissue. Simple analytical results of a further simplified model assuming purely surface heating agree well with results of a more detailed assessment for millimeter waves. Response of the model to pulse trains and to single maximum fluence “big bang”pulses in which all allowable energy over a 6-min averaging time is delivered in one short pulse raises the possibility of excessive transient temperature increases at the tissue surface from exposure to short high-fluence pulses at mm-wave frequencies. Such exposures are not produced by current technologies apart from certain military weapons systems but may occur from future high-power mm-wave technology. By contrast, simulations of exposure from a communications waveform at 1.9 GHz show extremely tiny transient temperature fluctuations. The results generally confirm the present choice of 6 min for an averaging time in the current generation of RF exposure limits but suggest the need for additional limits on fluence for brief high-fluence pulses at mm-wave frequencies. This paper addresses thermal hazards only, and a larger range of evidence would need to be evaluated as well in revising exposure limits.

Benzene is a carcinogenic pollutant with significant emission sources present in the atmosphere. The need for accurate and precise measurement of benzene in the atmosphere has become increasingly evident due to its toxicity and the adverse health effects associated with exposure to different concentrations. Certified reference material (CRM) is essential to establish the traceability of measurement results. The present review compiles the available national and international measurement methods, certified reference materials (CRMs) for benzene and the limit of benzene in fuel composition (v/v) worldwide. Overall, the review indicates the benzene level in the atmosphere and the resulting impacts on the environment and human health, which frequently exceed the exposure limits of different environment regulatory agencies. An extensive literature review was conducted to gather information on monitoring and analysis methods for benzene, revealing that the most preferred method, i.e. Gas Chromatography- Flame Ionization Detector and Mass Spectrometry, is neither cost-effective nor suitable for real-time continuous monitoring. By analysing existing literature and studies, this review will shed light on the understanding of the importance of benzene pollution monitoring in ambient air and its implications for public health. Additionally, it will reflect the mitigation strategies applied by regulators & need for future revisions of air quality guidelines.

Featured Application: The developed software facilitates the quick calculation of magnetic flux density produced by electric current in facilities in whichever conditions, which can be used to detect inadmissible levels of immission and to propose design improvements. The World Health Organization (WHO) warns that the presence of magnetic fields due to the circulation of industrial frequency electrical currents may have repercussions on the health of living beings. Hence, it is crucially important that we are able to quantify these fields under the normal operating conditions of the facilities, both in their premises and in their surroundings, in order to take the appropriate corrective measures and assure the safety conditions imposed, in force, by regulations. For this purpose, CRMag® software has been developed. Using the simplified Maxwell equations for low frequencies, CRMag® calculates and represents the magnetic flux density (MFD) that electrical currents produce in the environment. Users can easily model electrical facilities through a friendly and simple data entry. MFDs calculated by CRMag® have been validated in real facilities and laboratory tests. With this software, exposure levels can be studied in any hypothetical scenario, even in inaccessible zones. This allows designers to guarantee that legal limits (occupational, general population, or precautionary levels related to epidemiological studies) are fulfilled. A real case study has been described to show how the reconfiguration of conductors in a distribution transformer substation (DTS) allows significant reductions in MFD in some points outside the facility. [ABSTRACT FROM AUTHOR]

The results of a computer simulation examining the compliance of a given transcranial magnetic stimulation device to the 2010 International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines are presented. The objective was to update the safe distance estimates with the most current safety guidelines, as well as comparing these to values reported in previous publications. The 3D data generated was compared against results available in the literature, regarding the MCB-70 coil by Medtronic. Regarding occupational exposure, safe distances of 1.46 m and 0.96 m are derived from the simulation according to the 2003 and 2010 ICNIRP guidelines, respectively. These values are then compared to safe distances previously reported in other studies.

The results of a computer simulation examining the compliance of a given transcranial magnetic stimulation device to the 2010 International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines are presented. The objective was to update the safe distance estimates with the most current safety guidelines, as well as comparing these to values reported in previous publications. The 3D data generated was compared against results available in the literature, regarding the MCB-70 coil by Medtronic. Regarding occupational exposure, safe distances of 1.46 m and 0.96 m are derived from the simulation according to the 2003 and 2010 ICNIRP guidelines, respectively. These values are then compared to safe distances previously reported in other studies. [ABSTRACT FROM AUTHOR]

This work proposes exposure limits for carbon monoxide in the nuclear submarine environment. Linear and non-linear forms of the Coburn-Foster-Kane equation were used to evaluate carbon monoxide exposure for an environment with low oxygen content, different exposure times and crew physical activity levels. We evaluated the 90-day Continuous Exposure Guidance Level, 24-h and 1-h Emergency Exposure Guidance Levels and 10-day and 24-h Submarine Escape Action Levels. The results showed that the concentration of carbon monoxide in the environment must not exceed 9 ppm for the 90-day Continuous Exposure Guidance Level, 35 ppm for the 24-h Emergency Exposure Guidance Level, 90 ppm 1-h Emergency Exposure Guidance Level, 60 ppm for the 10-day Submarine Escape Action Level and 80 ppm for the 24-h Submarine Escape Action Level. Comparing these values with those established by the National Research Council for the United States Navy, the limits proposed by this work are verified to be lower, which may indicate a risk to the health of the crew. They also show the impact of the crew's level of physical activity on the formation of carboxyhemoglobin. [Display omitted] • Carbon monoxide exposure levels are lower when physical activity is considered. • Physical activity increases carboxyhemoglobin formation for short term exposure. • Linear CFK model showed closer fit to experimental data than the non-linear one. [ABSTRACT FROM AUTHOR]

The pharmaceutical industry is one of the most regulated industries in Switzerland. Though the concept of good manufacturing practises (GMP) was implemented for chemical production in the early 1990s, the rules and regulations for our industry are in constant evolution. In this article we will highlight the impact of these changes to the industry using three recent guideline up-dates as examples: the implementation of ICH Q3D 'Guideline for elemental impurities', the EU-GMP Guideline Part III Chapter 'Guideline on setting health based exposure limits for use in risk identification in the manufacture of different medicinal products in shared facilities' from 01. June 2015, and the new guidelines to data integrity such as 'PIC/S 041-1 Good Practices for Data Management and Integrity in regulated GMP/GDP environments'. These examples show how scientific approaches help to modernize the control strategies for our products and increase product quality for a better patient safety. The requirements of data integrity regulations are also of interest to industries and universities not working under GxP requirements as they also support the business to improve data quality (traceability) for patent applications, and reduce risk of data falsification.

The World Health Organization (WHO) warns that the presence of magnetic fields due to the circulation of industrial frequency electrical currents may have repercussions on the health of living beings. Hence, it is crucially important that we are able to quantify these fields under the normal operating conditions of the facilities, both in their premises and in their surroundings, in order to take the appropriate corrective measures and assure the safety conditions imposed, in force, by regulations. For this purpose, CRMag® software has been developed. Using the simplified Maxwell equations for low frequencies, CRMag® calculates and represents the magnetic flux density (MFD) that electrical currents produce in the environment. Users can easily model electrical facilities through a friendly and simple data entry. MFDs calculated by CRMag® have been validated in real facilities and laboratory tests. With this software, exposure levels can be studied in any hypothetical scenario, even in inaccessible zones. This allows designers to guarantee that legal limits (occupational, general population, or precautionary levels related to epidemiological studies) are fulfilled. A real case study has been described to show how the reconfiguration of conductors in a distribution transformer substation (DTS) allows significant reductions in MFD in some points outside the facility.

High intensity optical radiation can cause damage to the eye and intense radiation in the range of 770-1400 nm can cause thermal retinal damage. In the workplaces where there are high temperature sources, the workers in front of these hot sources without bright light maybe exposed to the intense IR radiation, thus regular measurement of these radiations seems crucial. Measurement of IR radiations by radiometer in specific wavelength ranges is elusive. Moreover, when radiometers are used, the correct application of the recommended exposure limits requires knowledge of spectral radiance which seems sophisticated for hygienists. The main objective of the present study is applying a model to express retinal thermal injury in terms of temperature for molten aluminum ovens in an aluminum foundry that emit optical radiation without visible light. In the proposed model, ACGIH TLVs for retinal thermal injury in the range of 770 to 1400 nm was used where source luminance was under 0.01 cd/cm2. Also, by using the output results of this proposed model it is possible to present a new chart for evaluation of exposure to IR for hot sources based on Threshold Temperature.

A research study was conducted to assess the effectiveness of cool coat in reducing heat strain among workers exposed to heat in a steel plant located in south India. The study consists of assessing heat strain of workers exposed to heat in a steel plant by measuring physiological reactions of workers such as pulse rate and core body temperature with and without cool coat. The coal coat taken for this study was procured from M/s Yamuna Industries, Noida. Out of 140 employees exposed to heat hazard, 101 employees were examined in this study. Study was done in important production units in steel plant having heat hazard. Workers were interviewed and examined and information regarding thermal comfort was collected. First, the heat strain was assessed when the workers were not using cool coats. The air temperature was measured at all hot zone workplaces and found in the range of 34 0 C to 39.4 0 C (Mean: 36.54 0 C & S.D: 1.54). Physiological response such as core body temperature, pulse rate and blood pressure of workers exposed to heat hazard were measured before & after work to know the heat strain sustained by workers when they were working. Maximum core body temperature after work was found to be 39.3 0 C (Mean; 38.52 & S.D; 0.7). Maximum pulse rate of workers after work was found to be 120 beats/minute (Mean; 94.96 beats/minute, S.D: 13.11). The study indicate core body temperature of workers was found more than the permissible exposure limit prescribed by ACGIH, indicating the heat strain sustained by workers is significant, whereas the pulse rate and blood pressure was found normal & not exceeded the limits. Second, with cool coat, the heat strain was assessed among 10 workers selected from the 101 employees. Core body temperature was measured before and soon after work, The core body temperature recorded soon after work was in the range of 35.5 - 37.20C (Mean 36.36, SD= 0.52), indicating a drop in the core body temperature. In this study, a core body temperature rise in the range of 1 0 -1.4 0 C was noticed when the employees were not wearing cool coats. Whereas, with the usage of cool coat a rise in core body temperature was not found and in many coat wearing workers a drop in core body temperature (0.2 to 0.9 0 C) was noticed. Employees revealed that the cool coats was comfortable to use and provided the thermal comforts. The study concluded that the cool coat taken for this study was found effective in reducing the heat strain. [ABSTRACT FROM AUTHOR]

Nanoparticles exist for a long time as both inorganic and organic parts of nature. Recently, massive expansion of nanotechnologies is evidenced, together with intentional production of new nanoparticles which have not been in contact with living organisms until now. Besides obvious positive aspects, potential threats related to their exposure should be taken into consideration. Unique physical-chemical properties of nanoparticles cause a high bioactivity following their intake (through air, ingestion and skin) and unrestricted spread in exposed organs. Primary effects of nanoparticles on cellular level represent oxidative stress and reactions leading to apoptosis, autophagocytosis and necrosis. Number of studies indicating contribution of nanoparticles to numerous disorders has been recently increasing. However, detailed mechanisms of health effects are not well known. Similarly, there is insufficient information on life cycle of nanoparticles in the environment. Research in this field as well as legislation is behind rapid development and use of nanotechnologies. Considering absence of mandatory exposure limits and other protective measures, nanomaterials represent a potential threat for population health. Recommendations and guidelines of international institutions can contribute to deal with situation, however, passing of effective legislation both on national and European level is urgently needed. [ABSTRACT FROM AUTHOR]

High intensity optical radiation can cause damage to the eye and intense radiation in the range of 770-1400 nm can cause thermal retinal damage. In the workplaces where there are high temperature sources, the workers in front of these hot sources without bright light maybe exposed to the intense IR radiation, thus regular measurement of these radiations seems crucial. Measurement of IR radiations by radiometer in specific wavelength ranges is elusive. Moreover, when radiometers are used, the correct application of the recommended exposure limits requires knowledge of spectral radiance which seems sophisticated for hygienists. The main objective of the present study is applying a model to express retinal thermal injury in terms of temperature for molten aluminum ovens in an aluminum foundry that emit optical radiation without visible light. In the proposed model, ACGIH TLVs for retinal thermal injury in the range of 770 to 1400 nm was used where source luminance was under 0.01 cd/cm2. Also, by using the output results of this proposed model it is possible to present a new chart for evaluation of exposure to IR for hot sources based on Threshold Temperature. [ABSTRACT FROM AUTHOR]

In this paper, a power tiller vibration was investigated at handle position as well as seat position of a trailer pulled by the power tiller. The experiments were conducted at five levels of engine speed, four levels of transmission gear ratio during transportation, and in three directions. Then the weighted 1/3rd octave spectrum was calculated from the narrow band vibration acceleration signals. The amount of vibration damage on operator's body and allowable exposure limits were calculated based on ISO standards. The results showed that the vibration increased with the engine speed increased for all the gear ratios and directions. The magnitude of vibration was the greatest at vertical direction in all the experiments. The vibration allowable exposure time was in the range of 2.32 - 5.7 years at the power tiller handle for the different engine speeds and gear ratios. The total equivalent vibration, A (8), at the trailer seat was in the range of 0.5 to 0.87 m/s2 and it exceeded the allowable limits for the reduced comfort boundary, fatigue-decreased boundary and exposure limit for 8 hrs day-1. So, it is necessary to reduce the vibration transmitted to the operator's hand and body by designing and developing adequate insulating systems. [ABSTRACT FROM AUTHOR]

A series of experiments were conducted in vivo using Yucatan miniature pigs (Sus scrofa domestica) to determine thermal damage thresholds to the skin from 1319-nm continuous-wave Nd:YAG laser irradiation. Experiments employed exposure durations of 0.25, 1.0, 2.5, and 10 s and beam diameters of ~0.6 and 1 cm. Thermal imagery data provided a time-dependent surface temperature response from the laser. A damage endpoint of fifty percent probability of a minimally visible effect was used to determine threshold for damage at 1 and 24 h postexposure. Predicted thermal response and damage thresholds are compared with a numerical model of optical-thermal interaction. Resultant trends with respect to exposure duration and beam diameter are compared with current standardized exposure limits for laser safety. Mathematical modeling agreed well with experimental data, predicting that though laser safety standards are sufficient for exposures <10 s, they may become less safe for very long exposures. [ABSTRACT FROM AUTHOR]

Abstract: Our study is the first to test if mandatory pollution disclosure programs, exemplified by the Toxics Release Inventory (TRI) program, reduce worker chemical exposure. We examine newly available measurements of personal exposure to air contaminants at 1333 plants in the US chemical manufacturing sector between 1984 and 2009. The maximum ratio of exposure to the legal limits per inspection declined substantially, by 11%, in the post-program period. This result provides the first evidence of a reduction in measured risks coinciding with the inception of the TRI program. We find suggestive, not conclusive, evidence to attribute this reduction in part to the TRI program. Our preferred specifications find that plants that are more responsive to the TRI program, as indicated by larger industry-level TRI emission reduction, had 6.5% to 8% lower exposure. However, not all models find statistically significant larger exposure reductions in plants that are more responsive to the TRI program. [Copyright &y& Elsevier]

The operators of the single-axle tractors are especially exposed to hand-arm transmitted vibrations. These vibrations can cause the complex of vascular, neurological and musculoskeletal disorders, collectively named hand-arm vibration syndrome. Among these, the most common disorder is vibration-induced white finger (Raynaud's phenomenon). The vibration levels were measured in three tractor's working conditions, namely idling, transportation and soil tillage. The vibration level on the handles was measured and analysed and the frequency spectra for the chosen working conditions were obtained. The frequency-weighted acceleration, given in m/s2, was calculated and the obtained values are graphically presented. The measured vibration levels are then discussed with regard to the operator's daily exposure limits recommended by the ISO 5349. The vibration levels were much higher in the x and y directions than the z- direction in all working conditions. The vibration total values in idling, transportation and soil tillage were 3.37, 8.37 and 9.62 m/s2, respectively. Results showed that the 10% of workers are exposed to a risk of vibration-induced white finger disorder of the hands after relatively short periods (3-4 years), if the tractor is used 8 hour per day in soil tillage and transportation at full load. Considering the criteria of the ISO 5349, the daily working time with the single-axle tractor should be limited in order to protect the operator and work schedules should be arranged to include vibration-free periods. [ABSTRACT FROM AUTHOR]

Transient current density J(t) induced in the body of a person exposed to a single magnetic pulse of arbitrary shape or to a magnetic jump is filtered by a convolution integral containing in its kernel the frequency and phase dependence of the basic limit value adopted in a way similar to that used for reference values in the International Commission on Non-lonising Radiation Protection statement. From the obtained time-dependent dimensionless impact function W(J)(t) can immediately be determined whether the exposure to the analysed single event complies with the basic limit. For very slowly varying field, the integral kernel is extended to include the softened ICNIRP basic limit for frequencies lower than 4 Hz. [ABSTRACT FROM AUTHOR]

The European Union (EU) has recently introduced a directive that aims to protect workers from adverse effects of exposure to electromagnetic fields. All countries within the EU are required to incorporate this directive into their national law by 2008. This legislation applies to all types of occupational exposure to electromagnetic fields with frequencies from 0 Hz to 300 GHz. It has dramatic implications for interventional magnetic resonance (MR) imaging, because workers who are close to the MR scanner while scanning is taking place are exposed at levels substantially above the exposure limits. This is especially the case for time-varying magnetic fields in the 110 Hz–5 kHz range, which includes the field from the imaging gradients. In this article, the scientific evidence on which the limits are based is brought into question. It is concluded that an urgent review of the directive is required and that more research, especially at MR gradient frequencies, is needed. [Copyright &y& Elsevier]

Abstract: At the moment there are more than 40 framesaws in use in Croatia, and many framesaw operators have a serious spine problem. Complex measurements have been carried out in order to determine the vibration level on the operator''s seat. This paper reports and analyzes the measurement results of the whole-body vibration transmitted to a framesaw operator during an ordinary working day. Vibrations were measured at all operations performed during the normal framesaw working cycle. For all the measurements frequency spectra were obtained and the results graphically represented according to the ISO 2631-1-1986 recommendations. The weighted r.m.s. acceleration was also calculated and the duration of each single framesaw operation was measured. The energy-equivalent vibration level, corresponding to the total duration of exposure was calculated, too. The values so obtained were compared with the daily exposure limits according to the ISO 2631-1-1997. The measurement results showed that the framesaw operator, under the given measuring conditions, is exposed to a higher vibration level than the given daily exposure limits. Also, the energy-equivalent vibration level calculated according to the guidelines given in the new ISO 2631-1-1997 is higher than the limits recommended for an effective 4-h daily exposure. [Copyright &y& Elsevier]

The paper presents research results of the vibration transmitted from the steering wheel of the small tractor with a 4-wheel drive to the driver''s hands. The vibration measurements were carried out on the tractor randomly chosen from the producer''s store-house. Before testing the tractor was examined and adjusted following the producer''s recommendations. The vibration levels were measured at idling and at full load. The vibration level on the steering wheel was measured and analyzed and the frequency spectra for the chosen working conditions were obtained. The frequency-weighted acceleration, given in m/s−2, was calculated. The vibration total value was defined as the root-mean-square of the three component values. The obtained values are graphically represented in accordance with ISO/DIS 5349-1979 and ISO5349-1-2001. The vibration exposure for the predicted 10% prevalance of vibration-induced white finger in accordance with Annex C of the same standard was also tested. [Copyright &y& Elsevier]

Occupational and environmental medicine evolved out of concern for the effect of work hazards on health. The experienced gained in considering such hazards has been extended to understanding general risks in the environment. As we look toward the future, classical occupational and environmental hazards such as over exposure to lead, asbestos and mercury are waning and being replaced by concerns around sustainable development, toxicology testing and exposure information for high production volume chemicals, development of better approaches for setting workplace and community exposure limits, environmental justice and many others. The opportunities for the future exist in overcoming these new challenges. [ABSTRACT FROM PUBLISHER]