Occupational Safety And Health Administration Research Articles

Classroom indoor air quality and noise level assessment of different educational institutions in a university area in Bangladesh

Introduction: The classroom environment is crucial for fostering effective learning and safeguarding teacher-student health. This study assessed the Indoor Air Quality (IAQ) and noise levels in classrooms across three institutions: a university, a secondary and higher secondary school (called a school and college), and a primary school. Materials and methods: Various IAQ parameters such as Particulate Matters (PM2.5 and PM10), Carbon monoxide (CO), Carbon dioxide (CO2), Total Volatile Organic Compound (TVOC), and temperature, Relative Humidity (RH), light, and noise levels were measured using calibrated instruments from February to March 2024. Results: The air pollutants and noise levels varied among the institutions. The mean values of PM 2.5 (76.6 µg/m3) and PM (116.7 µg/m3) were highest The mean values of PM 2.5 (76.6 µg/m3) and PM (116.7 µg/m3) were highest in the primary school, while CO (0.82 ppm), light (92.9 lux), temperature (27.6 °C), and noise levels (77.6 dB) peaked in the school and college. University classrooms showed the maximum concentrations of CO2 (804.9 ppm), TVOC (32.9 ppb), and RH (58.6%). In all institutions, PM2.5, PM10, and noise levels exceeded WHO-recommended limits, whereas CO, CO2, RH, and temperature remained within their respective standards. Light levels were below Occupational Safety and Health Administration (OSHA) guidelines. Correlation analysis showed significant positive correlations between PM2.5 PM10, and CO. Hazard Quotient (HQ) values for PM 2.5 and PM10 exceeded 1.0, indicating potential health risks. Variations in pollutants and noise levels among institutions may be due to classroom facilities, student density, ventilation systems, and student activities. Conclusion: Long-term exposure to IAQ pollutants and noise levels could impair cognitive function, respiratory health, and overall well-being of the students and educators. Implementing proper ventilation (e.g., HEPA filters) systems, soundproofing acoustic panels, and continuous IAQ monitoring is recommended for a safer classroom environment.

Methods for a Non-Targeted Qualitative Analysis and Quantification of Benzene, Toluene, and Xylenes by Gas Chromatography-Mass Spectrometry of E-Liquids and Aerosols in Commercially Available Electronic Cigarettes in Mexico.

The chemical components of the e-liquids and aerosols contained in electronic nicotine delivery systems (ENDSs), better known as vapes, were evaluated. The analytical technique used was gas chromatography-mass spectrometry, where the extraction and injection methods were established in this study. The work consisted of the analysis of twenty samples of disposable electronic cigarettes prefilled with new e-liquid, of a known brand, flavor, volume, and, in some of them, the percentage of nicotine and the number of puffs per device were indicated on the label. We detected the presence of many substances (at a qualitative and semi-quantitative level), and we achieved the quantification of benzene, toluene, and xylenes (BTX), dangerous substances that cause severe damage to health. Several of the e-liquids and aerosols present BTX concentrations above the permissible exposure limit (PEL), recommended by the Occupational Safety and Health Administration (OSHA): benzene in aerosol samples 80% > PEL, and toluene in aerosol samples 45% > PEL. The number of chemical compounds found in the samples increases from 13 to 167, the average being 52 compounds for the water extraction method, 42 compounds for the methanol extraction method of e-liquids, and 107 compounds for the direct aerosol analysis. It is a fact that many of those compounds, especially BTX, can cause serious effects on human health, affecting the respiratory, digestive, cardiovascular, pulmonary, and immune systems, as well as the brain. Therefore, the use of these devices should be considered with caution, since the substances and their chemical nature may pose significant health risks to both users and those exposed to secondhand emissions.

CFD modeling of reactive species air cleaner applications in a classroom

Due to increasing concerns related to airborne virus spread indoors, more reactive species air cleaners are being utilized in classrooms. Reactive species generated by air cleaners decompose airborne pathogens chemically, decreasing the risk of infection. Due to the high reactivity of these oxidants, reactive species may be distributed nonuniformly in indoor environments, as are viral aerosols emitted by infectors. Heterogeneous distributions of reactive species may cause spatially non-uniform removal rates of viral aerosols. However, there is little information regarding spatial distributions of either reactive species or viral aerosols in ventilated classrooms. Thus, the objective of this study was to investigate spatial distributions of reactive species and infectious aerosols and to examine how operating conditions of air cleaners affect viral aerosol removal rates. A CFD model simulated the operation of a reactive species air cleaner generating hydrogen peroxide (H2O2) in a mechanically ventilated 237 m3 classroom with nine occupants. The reactive species air cleaner showed a 3–20 times higher equivalent air change rate to a HEPA filter air cleaner with the same inlet and outlet flows. During the operation of reactive species air cleaners, elevated viral aerosol concentration was confined to regions near infectors. This was due to the high reactivity of reactive species, decreasing the infection probability of receptors from 3.2 % to 0.1 % with a 1-hour exposure time. As the room average concentration of reactive species increased from 15.6 to 50.4 ppb, both below the US Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (PEL) of 1000 ppb, the room average infection probability decreased from 0.3 % to 0.1 %. Due to the residence times of reactive species, the location of reactive species air cleaners affected the inactivation rate of viral aerosol, resulting in a 24 % variation of concentration difference of infectious aerosol with air cleaner locations.

Clinical Issues - September 2024.

Selecting nonsterile sharps disposal containers Key words: sharps safety, Occupational Safety and Health Administration (OSHA), bloodborne pathogens, occupational exposure, disposal container. Life support certification requirements for perioperative RNs Key words: basic life support, advanced cardiac life support (ACLS), cardiopulmonary resuscitation, certification, training. Using crisis checklists in the perioperative environment Key words: emergency manuals, cognitive aids, clinical emergencies, crew resource management, crisis checklist. Walking patients to the OR Key words: fall prevention, fall risk, mobility assessment, safe patient handling and mobility (SPHM), ambulate.

Traumatic workplace injuries: A cross-sectional analysis of OSHA severe injury reports, including the impacts of seasonality and COVID-19 from 2015 to 2022

Introduction: Millions of workers are injured on the job each year. Updated injury reporting regulations from the Occupational Safety and Health Administration (OSHA) in 2014 have resulted in publicly available data on reported severe injuries. Methods: OSHA severe injury reports (SIRs) were analyzed from 2015 to 2022. Severe injury rates were calculated using total employment estimates by industry and state to characterize the distribution of SIRs. Secondary analyses examined how SIRs differed seasonally, as well as before and after the start of the COVID-19 pandemic. Results: There were 83,338 severe workplace injuries reported across the 29 states that are under federal OSHA coverage. Manufacturing (375.98 per 100,000 workers) and Utilities (277.21 per 100,000 workers) had the highest rates of severe injuries. Despite summertime peaks in SIRs, there were not significant differences between seasons when examining SIRs by industry (p = 0.9763) or various injury factors. 1,846 of the SIRs were heat-related, and Utilities had the highest rate of heat-related severe injuries (13.34 per 100,000 workers). There was a statistically significant difference in the average injury rate when comparing pre- and post-COVID-19 periods (p < 0.001), which was statistically similar across all industries (p = 0.8143). Conclusions: Although several prior studies have examined the OSHA SIR data, this is the first known analysis of SIRs in relation to state- and industry-specific employment data. Despite the lack of a significant seasonality in SIRs, many industries seem to be impacted by heat-related injuries across all states. The number and rate of SIRs declined during COVID-19 similarly across all industries, with some industries maintaining low injury reporting rates through 2022. Practical Application: Findings of which industries and states may be experiencing a disproportionate burden of SIRs, including heat-related injuries, can inform injury prevention efforts. Additional work is needed to disentangle the drivers behind decreases in reported severe injuries during the COVID-19 pandemic.

Climatology of Wet-Bulb Globe Temperature and Associated Heat Waves in the U.S. Great Plains

Abstract Extreme heat such as that seen in the United States and Europe in summer 2022 can have significant impacts on human health and infrastructure. The Occupational Safety and Health Administration (OSHA) and the U.S. Army use wet-bulb globe temperature (WBGT) to quantify the impact of heat on workers and inform decisions on workload. WBGT is a weighted average of air temperature, natural wet-bulb temperature, and black globe temperature. A local hourly, daily, and monthly WBGT climatology will allow those planning outdoor work to minimize the likelihood of heat-related disruptions. In this study, WBGT is calculated from the ERA5 reanalysis and is validated by the Oklahoma Mesonet and found to be adequate. Two common methods of calculating WBGT from meteorological observations are compared. The Liljegren method has a larger diurnal cycle than the Dimiceli method, with a peak WBGT about 1°F higher. The high- and extreme-risk categories in the southern U.S. Great Plains (USGP) have increased from 5 days per year to 15 days from 1960 to 2020. Additionally, the largest increases in WBGT are occurring during DJF, potentially lengthening the warm season in the future. Heat wave definitions based on maximum, minimum, and mean WBGT are used to calculate heat wave characteristics and trends with the largest number of heat waves occurring in the southern USGP. Further, the number of heat waves is generally increasing across the domain. This study shows that heat wave days based on minimum WBGT have increased significantly which could have important impacts on human heat stress recovery.

OSHA and the Organizer

Although a morning visit from an Occupational Safety and Health Administration (OSHA) inspector is never a great way to start the day, it is a necessary aspect of ensuring compliance with OSHA rules. Now, however, with the introduction of an amendment to the OSHA walkaround rule that went into effect on May 31, 2024, that OSHA inspector may be accompanied by a union organizer wearing a pro‐union shirt with a QR code on the back for employees to scan. Moreover, by the time they both come knocking at your door, there is likely little that you as an employer can do.

Optimizing Indoor Air Quality to mitigate Sick Building Syndrome

- In current scenario, where individuals spend the majority of their time indoors, the quality of the indoor air has become increasingly crucial. This research paper investigates the role of optimizing Indoor Air Quality (IAQ) as a proactive strategy for mitigating Sick Building Syndrome (SBS) within built environments. It examines the relationship between indoor air quality (IAQ) and Sick Building Syndrome (SBS) in workplace settings and explores strategies for enhancing IAQ to mitigate SBS symptoms. Indoor air quality (IAQ) significantly impacts human health and well-being, with implications for productivity, comfort, and overall quality of life. To ensure safe and healthy indoor environments, various organizations, including the World Health Organization (WHO), Environmental Protection Agency (EPA), and Occupational Safety and Health Administration (OSHA), have established IAQ standards and guidelines. This research aims to conduct a comprehensive analysis of these standards. Moreover, the multifaceted nature of IAQ management is explored through the inclusion of parameters like radon (Rn), relative humidity (RH), and temperature. These factors not only contribute to indoor air quality but also affect occupants' comfort and well-being. By considering both chemical and environmental factors. Key Words: Indoor air quality, mitigate, policies, Sick building syndrome

Asbestos exposures associated with the use and handling of drilling mud additives.

This paper summarizes historical asbestos exposure data collected during the handling of short-fiber chrysotile asbestos that was used as an additive to drilling fluid in oil and gas exploration. A total of 1171 industrial hygiene (IH) personal and area air samples were collected and analyzed from more than 20 drilling rigs between 1972 and 1985. The dataset consists of 1097 short-term samples (<240min) with more than 80% having sample durations less than 30min. Average airborne fiber concentrations measured during asbestos handling activities ranged from 0.62 f/cc to 3.39 f/cc using phase-contrast microscopy (PCM). An additional 14 samples were considered long-term samples (>240min) and there were 60 samples with no reported sample duration. Eight-hour time-weighted average (8-h TWA) results, calculated using short-term samples, along with long-term samples greater than 240min, did not exceed contemporaneous Occupational Safety and Health Administration (OSHA) permissible exposure limits (PELs). This analysis fills a data gap in the evaluation of asbestos exposures from the use of drilling mud additives (DMAs) that contained chrysotile asbestos.

"Caminando Con Riesgo": perceptions of occupational injury, workplace safety and workers rights among Spanish-speaking hospitalized patients.

Occupational health disparities are well documented among immigrant populations and occupational injury remains a high cause of morbidity and mortality among immigrant populations. There are several factors that contribute to the high prevalence of work-related injury among this population and those without legal status are more likely to experience abusive labor practices that can lead to injury. While the work-related injuries and experiences of Spanish-speaking workers have been explored previously, there is a paucity of literature documenting injury among hospitalized patients. Additionally, there are few documented hospital-based occupational injury prevention programs and no programs that implement workers rights information. The purpose of this study was to further explore the context of work related injuries primarily experienced by Spanish speaking patients and knowledge of their rights in the workplace. This was a semi-structured qualitative interview study with Spanish speaking patients admitted to the hospital for work related injuries. The study team member conducting interviews was bilingual and trained in qualitative methodology. An interview guide was utilized for all interviews and was developed with an immigrant workers rights organization and study team expertise, and factors documented in the literature. Participants were asked about the type and context of the injury sustained, access and perceptions of workplace safety, and knowledge of participants rights as workers. All interviews were conducted in Spanish, recorded, transcribed in Spanish and then translated into English. A codebook was developed and refined iteratively and two independent coders coded all English transcripts using Dedoose. Interviews were conducted until thematic saturation was reached and data was analyzed using a thematic analysis approach. A total of eight interviews were completed. All participants reported working in hazardous conditions that resulted in an injury. Participants expressed a relative acceptance that their workplace environment was dangerous and acknowledged that injuries were common, essentially normalizing the risk of injury. There were varying reports of access to and utilization of safety information and equipment and employer engagement in safety was perceived as a facilitator to safety. Most participants did have some familiarity with Occupational Safety and Health Administration (OSHA) inspections but were not as familiar with OSHA procedures and their rights as workers. We identified several themes related to workplace injury among Spanish speaking patients, many of which raise concerns about access to workplace safety, re-injury and long-term recovery. The context around immigration is particularly important to consider and may lead to unique risk factors for injury, recovery, and re-injury both in the workplace and beyond the workplace, suggesting that perhaps immigration status alone may serve as a predisposition to injury. Thus, it is critical to understand the context around work related injuries in this population considering the tremendous impact of employment on one's health and financial stability. Further research on this topic is warranted, specifically the exploration of multiple intersecting layers of exposure to injury among immigrant populations. Future work should focus on hospital-based strategies for injury prevention and know your rights education tailored to Spanish speaking populations.

Examining the utility of near infrared light as pre-exposure therapy to mitigate temporary noise-induced hearing loss in humans.

This study sought to determine the effect of Occupational Safety and Health Administration (OSHA) compliant noise on auditory health and assess whether pre-noise near infrared (NIR) light therapy can mitigate the effects of noise exposure. Over four visits, participants (n = 30, NCT#: 03834714) with normal hearing completed baseline hearing health assessments followed by exposure to open ear, continuous pink noise at 94 dBA for 15 min. Immediately thereafter, post-noise hearing tests at 3000, 4000, and 6000 Hz and distortion product otoacoustic emissions (DPOAEs) were conducted along with the Modified Rhyme Test (MRT), Masking Level Difference Test (MLD), and Fixed Level Frequency Tests (FLFT) [collectively referred to as the Central and Peripheral Auditory Test Battery (CPATB)] to acquire baseline noise sensitivity profiles. Participants were then randomized to either Active or Sham NIR light therapy for 30 min binaurally to conclude Visit 1. Visit 2 (≥24 and ≤ 48 h from Visit 1) began with an additional 30-min session of Active NIR light therapy or Sham followed by repeat CPATB testing and noise exposure. Post-noise testing was again conducted immediately after noise exposure to assess the effect of NIR light therapy. The remaining visits were conducted following ≥2 weeks of noise rest in a cross-over design (i.e., those who had received Active NIR light therapy in Visits 1 and 2 received Sham therapy in Visits 3 and 4). Recovery hearing tests and DPOAEs were completed at the end of each visit. Participants experienced temporary threshold shifts (TTS) immediately following noise exposure, with a mean shift of 6.79 dB HL (±6.25), 10.61 dB HL (±6.89), and 7.30 dB HL (±7.25) at 3000, 4000, and 6000 Hz, respectively, though all thresholds returned to baseline at 3000, 4000, and 6000 Hz within 75 min of noise exposure. Paradoxically, Active NIR light therapy threshold shifts were statistically higher than Sham therapy at 3000 Hz (p = 0.04), but no other differences were observed at the other frequencies tested. An age sub-analysis demonstrated that TTS among younger adults were generally larger in the Sham therapy group versus Active therapy, though this was not statistically different. There were no differences in CPATB test results across Active or Sham groups. Finally, we observed no changes in auditory function or central processing following noise exposure, suggestive of healthy and resilient inner ears. In this study, locally administered NIR prior to noise exposure did not induce a significant protective effect in mitigating noise-induced TTS. Further exploration is needed to implement effective dosage and administration for this promising otoprotective therapy.

A critique of Occupational Safety and Health Administration's halfmask respirator assigned protection factor.

Halfmask air-purifying respirators are used by millions of workers to reduce inhaling air contaminants, both chemical (e.g., asbestos, styrene) and biological (e.g., SARS-CoV-2, Mycobacterium tuberculosis). In 2006, the federal Occupational Safety and Health Administration (OSHA) promulgated a standard that gave halfmask respirators an assigned protection factor (APF) of 10. This signified that OSHA assumes a fit-tested and trained wearer will experience a 10% maximum total inward leakage of contaminated air into the facepiece. To derive APF = 10, OSHA analyzed data from 16 workplace studies of the efficacy of halfmask respirators worn against particulate contaminants. In this commentary, I contend that, in considering the data, OSHA made several errors that overstated halfmask respirator efficacy. The errors were (i) failing to properly account for within-wearer and between-wearer variability in respirator efficacy; (ii) ignoring the effect of particle deposition in the respiratory tract; (iii) aggregating unbalanced data within and between studies, and effectively double-counting the data in some studies; and (iv) ignoring the effect that particle size exerts in penetrating respirator facepiece leak paths. The net result is that OSHA's APF = 10 can lead to excessive toxicant exposure for many workers.

Hydrogen sulfide chemiresistive sensor based on swift heavy ion irradiated cerium-based metal–organic framework/graphene oxide composite

Herein, we report ultrahigh sensitive and selective hydrogen sulfide (H2S) chemiresistive sensor using SHI irradiated cerium-based metal–organic framework (MOF)/graphene oxide composite (Ce-BTC/GO). The solvothermal synthesized Ce-BTC/GO coated on an indium tin oxide (ITO) electrode, irradiated by the 100 MeV Au+ ion at the fluence rate 5 × 1010 ions/s, 5 × 1011 ions/s and 5 × 1012 ions/s has been tested for chemiresistive sensing of H2S. As irradiated, Ce-BTC/GO was multi-parametrically tested for XRD, FE-SEM, FTIR spectroscopy, Raman spectroscopy and I-V characteristics for its structural, morphological, spectroscopic and electrical characteristics. The result reveals that the irradiation treatment greatly affects the electric characteristics of the GO, achieving dramatic conductivity modulation in the presence of H2S gas, it also creates the surface sites for the H2S absorption and hence shows excellent real-time sensing performance below the maximum residue limit established by OSHA (Occupational Safety and Health Administration). SHI irradiated Ce-BTC/GO sensor also shows excellent response/recovery time, ultrahigh reproducibility, good repeatability and stability at room temperature. The sensor allows the detection of H2S with a sensitivity of 54.70% in a concentration range of 10–100 ppm with a limit of detection 10 ppm.

Severity Analysis for Occupational Heat-related Injury Using the Multinomial Logit Model

BackgroundWorkers are often exposed to hazardous heat due to their work environment, leading to various injuries. As a result of climate change, heat-related injuries (HRIs) are becoming more problematic. This study aims to identify critical contributing factors to the severity of occupational HRIs. MethodsThis study analyzed historical injury reports from the Occupational Safety and Health Administration (OSHA). Contributing factors to the severity of HRIs were identified using text mining and model-free machine learning methods. The Multinomial Logit Model (MNL) was applied to explore the relationship between impact factors and the severity of HRIs. ResultsThe results indicated a higher risk of fatal HRIs among middle-aged, older, and male workers, particularly in the construction, service, manufacturing, and agriculture industries. In addition, a higher heat index, collapses, heart attacks, and fall accidents increased the severity of HRIs, while symptoms such as dehydration, dizziness, cramps, faintness, and vomiting reduced the likelihood of fatal HRIs. ConclusionsThe severity of HRIs was significantly influenced by factors like workers’ age, gender, industry type, heat index , symptoms, and secondary injuries. The findings underscore the need for tailored preventive strategies and training across different worker groups to mitigate HRIs risks.

Revolutionizing construction safety: introducing a cutting-edge virtual reality interactive system for training US construction workers to mitigate fall hazards

The construction industry is fraught with hazards, chief among them being the risk of falls from elevated positions, which are a leading cause of both fatalities and injuries among workers. Despite the prevalence of traditional safety training methods, their effectiveness in reducing fall risks remains limited. To solve this issue, this study proposes the adoption of interactive VR technologies to provide construction workers with immersive training experiences in the critical domain of fall safety. This approach not only ensures adherence to the Occupational Safety and Health Administration (OSHA) requirements but also leverages VR’s immersive capabilities to create a comprehensive and effective learning tool. To evaluate the proposed system’s efficacy, the researchers conducted an empirical assessment involving eighty-two construction workers from two small enterprises. Participants were divided into two groups: one receiving traditional training and the other undergoing VR-based instruction. Both groups underwent pre- and post-training evaluations comprising six targeted questions designed to measure the impact of each training method on their understanding and awareness of fall safety practices. The comparative analysis revealed no significant differences in baseline knowledge between the two groups prior to the training interventions. However, post-training evaluations demonstrated a notable improvement in the VR group, with a significant decrease in the number of incorrect responses, in stark contrast to the group subjected to traditional training methods. Statistical analysis further confirmed the superiority of VR training in enhancing participants’ knowledge. This was quantified by a p-value of 0.0016, indicating a high level of statistical significance well below the conventional threshold of 0.05. This study highlights the significant advantages of VR technology in construction safety training, demonstrating its superiority over traditional training methods in terms of knowledge retention and practical application. The results strongly support the wider adoption of VR in safety training, indicating its potential to enhance safety outcomes in the construction sector.

A comparison of neck and shoulder postures in symptomatic and asymptomatic female office workers in the actual work environment

ObjectiveThe present study aimed to compare the static and dynamic sitting posture during computer work among symptomatic and asymptomatic office workers in actual work environment. MethodsSeventy female office workers were divided into two groups: asymptomatic (n = 35) and symptomatic (n = 35). Subsequent to this classification, adjustments to their respective workstations were implemented in accordance with Occupational Safety and Health Administration (OSHA) guidelines. The assessment of neck (CV) and shoulder (FS) angles were conducted during both a typical seated posture and at intervals of 20 min over a duration of 3 h of computer work. ResultThe asymptomatic group had a range of age from 26 to 40 years, a BMI of 21.11 ± 2.14, and a working experience ranged from 1 to 16 years. In contrast, the symptomatic group had an age range from 24 to 40 years, a BMI of 21.12 ± 2.27, and a working experience ranged from 3 to 16 years. During static sitting posture, significant differences were observed in both CV (p = 0.01) and FS angles (p = 0.00) between the two groups. Additionally, during computer work sessions lasting for 3 h, a significant time effect (p = 0.00) was noted for the CV angle. Furthermore, the FS angle exhibited significant group (p = 0.00), time (p = 0.00), and interaction (p = 0.00) effects during work. ConclusionThis study underscores the development of neck flexion during prolong working in both groups. In addition, asymptomatic group experienced a progression more rounded shoulder during a 3-h working period. Prolonged periods of sitting and computer use appear to have adverse effects on neck and shoulder health, underlining the importance of implementing measures to mitigate these effects.

Working With the Strategy Master-Dr Michael Silverstein MD, MPH [1945-2024

New Solutions offers a short memorial statement noting the January 2, 2024, death of Dr Michael Silverstein, an internationally known leader in the field of occupational health and safety. Dr Silverstein spent 53 years specializing in the fields of occupational medicine, public health, and general preventive medicine. He was the Assistant Director for Occupational Health and Safety with the United Automobile Workers Union for 15 years. He served as the Director of Policy for the U.S. Occupational Safety and Health Administration (OSHA) during the Clinton Administration. He later served as Director of the Washington State OSHA program for 10 years and was the Assistant Director for Industrial Safety and Health in the Washington State Department of Labor and Industries. A long-time friend of New Solutions, Dr Silverstein was the journal's first Scientific Solutions editor.

Sound levels of the UVU pedestrian bridge

Utah Valley University provides a pedestrian bridge to travel from a train station to the school over Interstate-15. Due to traffic noise, people using the bridge could be exposed to sound levels that damage their hearing. Sound level measurements have been made at several locations on the bridge with two different instruments, the first being an Extech (Knoxville, USA) SL400 noise dosimeter and the other being a Larson Davis (Depew, USA) 831C sound level meter. Sound levels have ranged from 55 to 102 dB, depending on time of day and location on the bridge. In addition to our experimental results a COMSOL model was also developed to simulate the interactions of the freeway noise with the bridge, demonstrating how the geometry of the bridge affects the noise exposure of pedestrians. The Occupational Safety and Health Administration (OSHA) limit for non-occupational noise exposure of 100 dB is 15 minutes, suggesting that pedestrians that linger on the bridge could be exposed to damaging levels of sound. This research seeks to better understand and quantify the noise levels that pedestrians experience on the bridge.

Factors influencing safety behaviours of construction tradesmen

The Occupational Safety and Health Administration (OSHA) observed that 90% of fatalities arise from the familiar ‘fatal four’- falls, electrocutions, stuck-bys and caught –in between. American Industrial Hygiene Association (AIHA) also fingered other four hazards due to exposures on construction jobs not paid attention to yet far more construction workers suffer chronic injuries or illness. These infamous concerns make research findings on factors influencing safety behaviours of construction workers ever relevant and this is the focus of this paper. A total of 117 construction tradesmen out of the 159 sampled within Lagos indicated their degree of agreement with factors capable of influencing construction workers’ safety behaviour on a five-point Likert scale. These were factors adjudged to influence construction workers safety behaviour based on extant literature. The data were analysed using Mean Item Score and Factor Analysis. Construction tradesmen agreed that they are influenced by 25 of the 37 (67.56%) identified factors influencing safety behaviour firms of construction workers. Meanwhile, construction firms’ management commitment to the safety behaviour of tradesmen is the most prominent principal factor. The commitment of the management in developing safety initiatives, training, provision of personal protective equipment, and enforcement of safety rules among others will enhance safety behaviour among construction tradesmen. The study only assessed the opinions of tradesmen in the construction industry in Lagos state. The identified factors might not be generalized to construction professionals. This paper recommends that construction managers make deliberate effort in enhancing good safe behaviour of their tradesmen. This will improve their physical wellbeing, boost construction health and safety in the construction industry and significantly reduce construction fatalities. This paper fulfils a present pertinent need of reducing construction fatalities by focusing on factors influencing the safety behaviour of construction tradesmen.

Comparison and analysis research on occupational exposure limits of coal dust between China and foreign countries

Objective: To study and compare the occupational exposure limits (OELs) of coal dust between China and foreign countries, understand the OEL of coal dust in China, and provide data and basis for revising the OEL of coal dust in China. Methods: In August 2023, by searching the official websites of limits setting institutions in relevant countries and regions at home and abroad, collecting and sorting out the OELs of coal dust issued by 10 limit setting institutions in 6 countries and the background information of the formulation, and conducting specific analysis on the classification, limit level and formulation principles of coal dust OEL in each country/institution. Results: In China and Japan, the total dust and respirable dust of coal dust OEL were established respectively, while in other countries, only the time-weighted average concentration (TWA) of respirable coal dust exposure was established. The TWA prescribed by China's Notional Health Commission, the United States Occupational Safety and Health Administration (OSHA) , the United States Mining Safety and Health Administration (MSHA) and the Australian Safety Work Bureau when the SiO(2) content was less than 5% were 5, 2.4, 2 and 3 mg/m(3) respectively. China GBZ 2.1-2019 sets the limit of 2.5 mg/m(3) for respirable coal dust with SiO(2) content less than 10%. The TWA set by the American Conference of Government Industrial Hygienists (ACGIH) and the South African Department of Mines and Energy (DME) for anthracite coal were 0.4 and 0.8 mg/m(3), respectively, and bituminous coal or lignite were 0.9 and 1.8 mg/m(3), respectively. The respirable coal dust TWA set by the National Institute for Occupational Safety and Health (NIOSH) in the United States was 1 mg/m(3), and the TWA set by the New Zealand Work Safety Authority was 3 mg/m(3). Conclusion: At present, the OEL of coal dust in China is at a relatively loose level, and it is suggested to further explore the possibility of revising coal dust OEL.