Journal of Occupational and Environmental Hygiene最新文献

During the COVID-19 pandemic, concerns about potential airborne virus transmission and exposure during musical performances were raised. Past studies suggest that aerosols are emitted from exhaling and talking with varying magnitudes. Meanwhile, little was known about aerosol emissions from singing and playing wind instruments. The objective of this study was to examine the spatial and temporal build-up of aerosol concentration in a typical studio room where singing, talking, and playing wind instruments are involved, to represent musical practicing and teaching scenarios at the University of Cincinnati College-Conservatory of Music (CCM). Four condensation particle counters were strategically placed throughout a room at various distances from the performer. Besides singing, musical professionals played seven instruments (clarinet, flute, French horn, saxophone, trombone, trumpet, and tuba). Two types of tests were conducted for each instrument: 10 min of playing and 10 min of combined playing and talking to mimic the teaching session. The results show that singing increased aerosol concentration to 3.9 × 10³ cm^-3 at the performing point, more than double the background (1.2 × 10³ cm^-3). Most wind instruments had minimal but detectable emission of aerosols over time, suggesting instruments could provide wall deposition for aerosols compared to singing. Particle concentrations decreased further from the performing point; however, they were still detectable over the background level at 10 feet away. Use of a portable high-efficiency particulate air (HEPA) filtration reduced aerosol concentrations developed during musical performances to below background level. These findings suggest that there are risks associated with aerosolized transmission of infectious agents such as SARS-CoV-2 from musical performance if the performer is infected. Distancing beyond the 6 ft distancing recommendation and proper room and local ventilation combined with disinfecting procedures are needed to minimize the risk of exposure to infectious aerosols.

Seafood processing workers have a high prevalence of respiratory symptoms and occupational asthma, primarily attributed to allergenic protein exposure. However, exposure to airborne microorganisms from raw materials can also contribute to allergic sensitization and other respiratory ailments. This study aimed to assess microbial exposure in shrimp processing plants and identify susceptible work tasks. Full-shift personal air samples were collected from two Norwegian shrimp processing plants across five distinct work processes: thawing, truck driving, cooking-peeling (technician), packing, and flour production. The samples were analyzed for the presence of endotoxin, Toll-Like Receptor (TLR) activation, bacterial and fungal DNA copies, and microbial composition. Endotoxin levels were generally low, with only one sample (98 EU/m³) exceeding the recommended occupational exposure limit (OEL). A significant TLR2 activation was observed among thawers, indicating the presence of microbial ligands capable of triggering an immune response. The median bacterial (75 × 10³ DNA copies/m³) and fungal (3,301 × 10³ DNA copies/m³) exposure were highest among the flour production workers, while the lowest bacterial and fungal exposure was among packers (1.5 × 10³ DNA copies/m³) and technicians (337 DNA copies/m³), respectively. Several bacterial and fungal species were identified, including ten allergenic and sixteen pathogenic species. Sporobolomyces roseus and Saccharomyces cerevisiae were the two most frequently identified allergenic fungal species. Among the pathogenic bacterial species, Prevotella nigrescens and Roseomonas gilardii were the two most detected species. While the pathogenic species were identified mainly in the packing, truck driving, and flour production work processes, most of the allergenic species were found in all work processes. Altogether, work processes before the cooking of shrimp (thawing and truck driving) had higher endotoxin, bacterial load, and species richness than after cooking, suggesting that these work tasks are susceptible to bacterial exposure and that the cooking process significantly reduces bacterial exposure. By shedding light on microbial exposure and identifying high-exposure work tasks, this study enables the development of targeted interventions and implementation of measures for the prevention of occupational diseases.

Kindergarten dormitories are indoor napping areas where preschool children spend extended periods nearby, making them high-risk environments for the transmission of respiratory diseases. To understand the transmission characteristics of respiratory pollutants, particularly CO₂ and simulated cough aerosols between adjacent beds, two common bed layouts in kindergartens were investigated: three beds of staggered height (TBSH) and three beds of uniform height (TBUH). The experiments measured CO₂ and PM_2.5 concentrations (using liquid aerosols generated by an ultrasonic nebulizer as surrogates for cough particles) in the breathing zone of mannequins under different ventilation modes (on and off) and sleeping postures (lying face up and on the right side). The results showed that when ventilation was off, CO₂ concentration near the head of each bed reached nearly 1,000 ppm within 60 min. When ventilation was on, CO₂ concentration was diluted to ambient levels within 3.3 min. However, when the ventilation was on, aerosols exhibited different propagation characteristics compared to CO₂. While CO₂ was rapidly diluted, aerosols accumulated downstream and formed high-concentration zones at adjacent downstream beds. These findings visualize the potential aerosol transmission pathways between beds in kindergarten dormitories and highlight the limitations of using CO₂ as an aerosol transmission tracer. The study found that increasing bed heights along the ventilation airflow direction effectively reduced downstream aerosol concentrations and compensated for the insufficient horizontal distance in kindergarten dormitories. Kindergarten design standards should consider local dilution efficiency in the breathing zone, and bed layouts should be integrated with the ventilation system to ensure air velocities exceed 0.01 m/s near the head, thereby reducing the residence time of pollutants in the breathing zone.

This study assessed the performance of the Institute of Occupational Medicine (IOM) and Gesamtstaubprobenahme (GSP) personal inhalable aerosol samplers in measuring aerosol and soluble protein (SP) concentrations across 12 food industry environments. A total of 193 sampling pairs (GSP and IOM) were analyzed for inhalable aerosols, and 185 sampling pairs for SP. Median aerosol concentrations ranged from 0.2 mg/m³ in snacks, nuts, and chips production to 5.6 mg/m³ in spreads production. The IOM sample had a median aerosol concentration of 1.8 mg/m³, while the GSP had a slightly lower median of 1.4 mg/m³, generally collecting 17% less inhalable aerosol than the IOM in most environments. The IOM also included wall deposits in its gravimetric determinations, contributing an additional 10-30% to the overall aerosol concentrations. For SP concentrations, the IOM measured higher aerosol concentrations in environments with a particle size distribution dominated by larger particles, while the GSP showed higher SP concentrations in environments dominated by smaller, respirable particles. The Tobit mixed-effect models showed that the IOM had statistically significantly higher aerosol concentrations compared to the GSP, but significantly lower SP concentrations than the GSP. However, these differences between the samplers were relatively small, suggesting that in occupational hygiene practices, both samplers can be used.

Artisanal mining in Nigeria is growing along with the increase in the price of metals. However, self-employed miners, particularly in the northwest of the country, have brought extensive environmental contamination and severe lead poisoning from the lead content in the ore. This study assessed airborne lead exposures to miners during lead mining and gold ore processing in three villages in Zamfara State, Nigeria. Personal air samples were collected and analyzed for lead content. Gold processing operations were classified by task, including: manual mortar and pestle grinding, hammer crushing, and mechanical stone crushing and grinding operations with diesel-powered equipment. Separately, exposures were evaluated among underground lead miners. This study collected a total of 47 air samples, including 32 from gold ore processing sites and 15 from lead mining sites. The results indicated that underground miners were exposed to airborne lead at a mean concentration of 0.48 mg/m³, or approximately 10-fold the United States Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (PEL). Furthermore, miners at gold processing sites were exposed to airborne lead at a mean concentration of 1.59 mg/m³ for both mechanical and manual tasks, which is approximately 32-fold the PEL. Manual gold ore processing resulted in mean airborne lead exposures of 1.74 mg/m³, and those using mechanical methods had a mean concentration of 1.52 mg/m³. The results also indicated that the order of airborne lead level exposure was as follows: mortar and pestle operators > crusher operators > hammer operators > grinder operators > underground lead miners. Lead mining operations and gold ore processing consistently had elevated airborne lead at levels, posing risks of acute lead poisoning, and are likely contributing to take-home lead exposures observed in these communities. These results are consistent with the lead contamination of soil observed in housing compounds and at processing sites in this region. To address these risk factors, safer mine training and the adoption of wet methods were encouraged along with changes to personal hygiene practices and other measures to mitigate exposure and to protect miners and their communities.

Electrosurgery generates surgical smoke, which contains hazardous compounds. The concentration, composition, and size distribution of surgical smoke vary significantly with surgery type, duration, and number of times electrocautery is used. Exposure assessments have focused on characterizing occupational exposure to surgical smoke during human surgeries, but occupational exposure to surgical smoke during veterinary surgeries is largely unknown. Given the hazardous exposure concentrations identified in human surgical procedures, similar occupational exposures are expected in small animal surgeries. Thus, there is a critical need to evaluate occupational exposures among veterinarians conducting small animal surgeries and to evaluate potential exposure reduction systems. The objectives of the study are to quantify the particle number concentration and size distribution during canine limb amputation (CLA) surgery and to quantify the exposure reductions associated with a smoke evacuation system (SES). Exposure to ultrafine particles (UFP) during CLA was measured using a TSI NanoScan Scanning Mobility Particle Sizer (SMPS) Nanoparticle Sizer 3910 during surgeries with and without the SES. Particle number concentrations were 11 times higher compared to background concentrations during CLA surgeries. The particle number concentration was significantly reduced when using SES during surgery compared to surgeries without SES. The average total particle number concentration near the veterinarian's breathing zone was 25,141 particles/cm³ for surgeries without SES and 7,643 particles/cm³ when the SES was used during surgeries, which represents about a 70% reduction in exposure. CLA was associated with particle exposures similar to those seen in human surgeries. The use of SES effectively reduced the concentration of particles near the surgeon's breathing zone.

Firefighters (FFs) are occupationally exposed to many carcinogens, including polycyclic aromatic hydrocarbons (PAHs). Previous studies have evaluated PAH contamination on FFs' personal protective equipment (PPE), including fire gloves; however, there is a need to better understand PAH contamination that may break through fire gloves during active firefighting, donning, and doffing of PPE. Researchers in this study aimed to understand the potential contamination of FFs' hands during firefighting activities. A pilot study was conducted with 23 FFs, asking them to wear up to 3 separate sets of newly opened cotton undergloves during (1) donning, (2) simulated firefighting activities conducted in a smoky environment, and (3) doffing activities (donning and firefighting were combined for some samples). Samples were taken from the palm, index finger, and thumb areas of the cotton gloves and analyzed for PAHs. Overall, it was found that fire gloves were relatively effective at minimizing PAH exposure on the hands (undergloves) during active firefighting operations, though some PAH contamination was still present. PAH contamination was highest during the doffing of PPE and was significantly higher on the thumb and finger relative to the palm (p values < 0.05). PAH contamination was found in the cotton gloves during donning, even though FFs' self-contained breathing apparatuses were cleaned and the turnout gear was previously laundered, using commercial extractors. Future research could explore the potential for contaminated, decontaminated, and/or laundered gear to present contamination risks to fire personnel and investigate the use of undergloves as additional protection for FFs' skin.

Assessing and minimizing potential health risks from chemical exposure in the workplace is a crucial role for an industrial hygiene professional. It is also a core objective for government agencies conducting research, developing guidance, and enforcing laws to protect occupational populations. The specific methods for occupational risk assessment-and in some cases, the sophistication of these methods-are evolving in the face of emerging technologies and changing regulations. Occupational health risks identified in recent agency assessments have led to increased dialogue among stakeholders and agencies regarding foundational practices and opportunities for standardizing a baseline methodology that can be made fit-for-purpose for specific programs. In response, the Foundation for Chemistry Research and Initiatives (FCRI) and the American Industrial Hygiene Association (AIHA)^® jointly initiated a workshop series with an overall objective to facilitate conversations and knowledge-sharing regarding best practices for occupational risk assessment. This review summarizes the major topics discussed at the workshops and presents key guidance documents and other resources identified during and following the series. Specific topics discussed included: (1) foundational practices for collecting empirical industrial hygiene data, (2) optimizing use of near-field exposure models, (3) improving dermal exposure assessment, and (4) developing and applying occupational exposure limits for risk management. An overarching theme across the series was that while there often is no single best method, the goals of the assessment must be considered when selecting the methods and tools for each assessment. In other words, the nature of the question or issue that the risk assessor is addressing in the assessment must be defined and considered before starting the assessment and throughout its entirety, including when interpreting the results.