Recommended Exposure Levels Research Articles

Adverse effects in traditional and alternative toxicity tests

Chemical safety assessment begins with defining the lowest level of chemical that alters one or more measured endpoints. This critical effect level, along with factors to account for uncertainty, is used to derive limits for human exposure. In the absence of data regarding the specific mechanisms or biological pathways affected, non-specific endpoints such as body weight and non-target organ weight changes are used to set critical effect levels. Specific apical endpoints such as impaired reproductive function or altered neurodevelopment have also been used to set chemical safety limits; however, in test guidelines designed for specific apical effect(s), concurrently measured non-specific endpoints may be equally or more sensitive than specific endpoints. This means that rather than predicting a specific toxicological response, animal data are often used to develop protective critical effect levels, without assuming the same change would be observed in humans. This manuscript is intended to encourage a rethinking of how adverse chemical effects are interpreted: non-specific endpoints from in vivo toxicological studies data are often used to derive points of departure for use with safety assessment factors to create recommended exposure levels that are broadly protective but not necessarily target-specific.

Antipsychotics and Mortality in Adult and Geriatric Patients with Schizophrenia.

Patients with schizophrenia have a high mortality risk, and the role of antipsychotic medications remains inconclusive. In an aging society, older patients with schizophrenia warrant increased attention. This study investigated the association of antipsychotic medication dosages with mortality in patients with schizophrenia by using data from Taiwan's National Health Insurance Research Database from 2010 to 2014. This study included 102,964 patients with schizophrenia and a subgroup of 6433 older patients in addition to an age- and sex-matched control group. The findings revealed that among patients with schizophrenia, the no antipsychotic exposure group had the highest mortality risk (3.61- and 3.37-fold higher risk for overall and cardiovascular mortality, respectively) in the age- and sex-adjusted model, followed by the high, low, and moderate exposure groups. A similar pattern was observed in the older patients with schizophrenia. High exposure to antipsychotics was associated with the highest risks of overall and cardiovascular mortality (3.01- and 2.95-fold higher risk, respectively). In conclusion, the use of antipsychotics can be beneficial for patients with schizophrenia with recommended exposure levels being low to moderate. In older patients, high antipsychotic exposure was associated with the highest mortality risk, indicating that clinicians should be cautious when administering antipsychotic medications to such patients.

Full-scale determination of essential oil diffusion: Impact on indoor air quality

Essential oils have attracted increasing interest, as they inhibit the metabolic functions of microorganisms. Essential oils are claimed to improve indoor air quality through passive remediation and purifying activities. However, the impact of diffused essential oils on indoor air quality has not been clearly established from a VOC point of view. This study aims to assess the emissions produced by terpene molecules in tea tree essential oil by employing two types of widespread diffusers under real conditions using a full-scale experimental room (40 m3). The emissions generated by terpenoid volatile organic compounds (TerVOCs) are different depending on the type of diffuser. The relative contributions of individual terpenes in the gas phase vary throughout the diffusion process. The impact of tea tree essential oil diffusion on indoor air quality varies from 6 h to 51 days, depending on the diffusion device. Concentration levels can exceed European recommended exposure levels by more than one order of magnitude. Interestingly, the volume of the emission chamber directly impacts the emission dynamics of essential oil constituents. Small chambers may limit the volume of air to be contaminated and possibly impacts the magnitude of concentration gradients during diffusion. This work evidences the interest of using full-scale experimental facilities to determine accurate emission rates. A full-scale experimental methodology including data treatment is validated in this work. Through the proposed protocol, representative emission factors can be determined to assess exposure and perform indoor air modelling.

124 A wild rice byproduct compares well to traditional wood sawdust as bedding material

Minnesota is one of the largest producers of cultivated wild rice in the US, and the straw-like byproduct (rice knuckles) may provide an alternative bedding material for horses while supporting sustainability. Bedding selection is an important factor to provide a healthy environment for horses. This study evaluated the suitability of wild rice knuckles (RK) as an alternative bedding material to traditional wood sawdust (WS) by comparing water absorptive capacity (WAC), air quality, and ammonia levels. Four mature horses (>3 yr old) were used in the crossover study. Horses were randomly assigned to bedding type (RK or WS) for 5 d, then switched to the other bedding type for the next 5 d. Horses were housed in box stalls at night and turned out in paddocks during the day. Total muck production was recorded daily after stall cleaning by 3 individuals. The WAC was tested by soaking bedding material (n = 2) in water using nylon pantyhose for 0, 1, 3, 6, 9, and 24 h and recording the change in weight. An Elitech air quality monitor recorded the concentration of 3 sizes of suspended particulate matter (PM < 2.5 µg/m3, 10 µg/m3, and total PM). Air quality was recorded 3 m above the stall surface after horses were stalled over night and during stall cleaning. Ammonia was measured in the horse's breathing zone by attaching Draeger tubes to horse's halters for 12 h overnight and instantaneous ammonia levels were measured each morning in the stalls.Changes over time in WAC, ammonia, muck production, and air quality were analyzed using a mixed model ANOVA with repeated measures (SAS 9.4). The WAC was higher in WS compared with RK (P = 0.0057) but there was no difference in total muck produced (P = 0.5931). There was no main effect of bedding type on suspended PM (P > 0.05) but there was an increase over time across bedding types (P < 0.05). Suspended PM was lowest the first day and increased during subsequent days. During stall cleaning there were no differences in air quality between bedding type (P > 0.05), however, the average PM 2.5 level (51.5 ± 14.7 µg/m3) was higher than recommended exposure levels (35 µg/m3) for caretakers. Ammonia levels in the RK stalls were lower than stalls bedded with WS (4.65 ± 2.4 ppm and 6.88 ± 2.4 ppm, respectively; P = 0.0125). Horses bedded on RK were exposed to lower levels of ammonia in their breathing zone compared with horses bedded on WS (P = 0.003). Overall, RK appear to be a suitable alternative bedding type to traditional WS. Although the WAC is lower, bedding with RK reduces ammonia exposure of horses and their caretakers. Utilization of agricultural byproducts as bedding provides an opportunity to extract value from these byproducts.

Critical aspects in occupational exposure assessment with different aerosol metrics in an industrial spray coating process

Engineered Nanomaterials (ENMs) have several uses in various industrial fields and are embedded in a myriad of consumer products. However, there is continued concern over the potential adverse health effects and environmental impacts of ENMs due to their unique physico-chemical characteristics. Currently, there are no specific international regulations for various ENMs. There are also no Occupational Exposure Limits (OEL) regulated by the European Union (EU) for nanomaterials in the form of nano-objects, their aggregates or agglomerates (NOAA). For ENMs the question of which metric to be used (i.e., mass, surface area, number concentrations) to determine the exposure is still not resolved. The aim of this work is to assess the worker exposure by inhalation in an industrial spray coating process by using all three metrics mentioned above. Two target ENMs (N-doped TiO2, TiO2N and AgNPs capped with a quaternized hydroxyethyl-cellulose, AgHEC) generated for industrial-scale spraying processes were considered. Results showed that the averaged particle number concentration (10–100 nm) was below 2.7 104 cm−3 for both materials. The Lung Deposited Surface Area (LDSA) was in the range between 73 and 98 μm2cm−3 and the particle mass concentration (obtained by means of ICP-EOS off-line analysis) resulted below 70 μg m−3 and 0.4 μg m−3 for TiO2 and Ag, respectively. Although, the airborne particles concentration compared well with the NIOSH Recommended Exposure Level (REL) limits the contribution to the background, according to EN 17058 (Annex E) was significant (particularly in the particle number and PM1 mass concentrations). We successfully evaluated the worker exposure by means of the different airborne particles' metrics (number, surface and mass concentrations). We concluded that worker exposure assessment involving ENMs is a complex procedure with requires both real time and off-line measurements and a deep investigation of the background.

Design and testing of a personalized noise monitoring system

Agricultural workers are more prone to noise-induced hearing loss than are many other workers. Hearing protection device use among agricultural workers is low, but training can increase hearing protection device use. This work proposes a system designed to automatically inform agricultural workers when they were exposed to noises that exceed the National Institute for Occupational Safety and Health (NIOSH) recommended exposure level. The smartphone-based system worn on the arm uses a noise dosimeter to measure noise exposures throughout the day to within ±2 A-weighted decibels of a Class 2 sound level meter. The device collects location and audio data, which are transferred to a server and presented to the worker on a locally hosted website. The website details noise exposure and helps the worker identify where exposure occurred and what specific tasks exceed NIOSH’s recommended exposure limit, putting them at higher risk of noise-induced hearing loss. With this understanding, the worker is expected to adopt behavior changes and better hearing protection use at critical places and times. This pilot study evaluates the accuracy of the noise dosimeter and GPS relative to gold-standard instruments. The system was tested on a farm with outputs compared with gold-standard instruments. A-weighted, 1-sec averaged sound pressure levels and position data were collected while users were performing a variety of tasks indoors and outdoors. The smartphone’s external noise dosimeter read within ±2 A-weighted decibels of the Class 2 reference dosimeter 59% of the time. The positioning devices had an average error of sub-4 m. While not perfectly matching gold-standard instruments, the device is capable of identifying and collecting information relative to loud noise events that promote noise-induced hearing loss.

Assessing Radiographic Technologist Precision and its Influence on Patient Exposure Index: Analytical Retrospective Study in a Small Palestinian Government Hospital

This observational retrospective study conducted at Hussein Governmental Hospital in Bethlehem, Palestine, aimed to compare internationally recommended exposure levels with the actual exposure settings employed by radiation technologists. Inclusive of both genders and diverse age groups, the study utilized Toshiba flat panel detectors and closely observed exposures across various radiographic image types. Data analysis, performed using SPSS, included a one-sample t-test, ANOVA, and Pearson correlation. The results revealed that, on average, the current Exposure Index (EXI) did not significantly differ from the recommended standards, indicating the proficiency of technologists. However, deviations were observed in Kilovoltage Peak (kVp) settings, emphasizing the need for technologists to interpret automatic exposure controls accurately. The study found no significant differences in EXI related to image type, gender, or age, affirming the logical correlation between parameters and distinct exposure indices. Notably, a significant relationship was observed between acceptance by technologists and the Deviation Index, suggesting challenges in visually distinguishing accepted and rejected images.&#x0D; Originality/value: This study assesses radiation technologists' adherence to international exposure standards using Toshiba detectors. While overall compliance is observed, deviations in Kilovoltage Peak settings indicate a need for improved control interpretation. The findings contribute to optimizing radiation exposure and image quality in clinical radiography, particularly in resource-constrained settings.

The National Institute for Occupational Safety and Health recommended exposure level for noise needs to be revised downwards

Noise-induced hearing loss (NIHL) is caused by cumulative occupational and non-occupational noise exposure. The National Institute for Occupational Safety and Health (NIOSH) developed recommendations for occupational noise exposure in 1972, revised in 1998. Fifty years after the NIOSH 85 dBA recommended exposure level (REL) was first published, it needs to be revised downwards. In its calculations, NIOSH assumed that workers have quiet (&amp;lt;60 dBA) when not at work, something no longer true. Everyday public noise exposure now exceeds the Environmental Protection Agency's safe noise level, a time-weighted average of 70 dB for 24 hours, with multiple studies reporting average exposures near 75 dBA. Also, NIOSH calculations were based on occupational studies of material hearing loss measured by limited frequency pure tone audiometry, an insensitive measure of noise-induced auditory damage. Modern audiology techniques include extended range audiometry, speech in noise testing, diffusion product otoacoustic emissions testing, and questions about tinnitus and hyperacusis. Doing the needed research to support downward REL revision, detecting auditory damage in noise-exposed workers with these newer techniques, is a daunting task, but this is necessary both to protect workers and because the NIOSH REL forms the basis for the world's recommendations for non-occupational noise exposure.

What is the safe noise level to prevent noise-induced hearing loss?

Noise causes short-term mechanical and chemical changes in the cochlea, transduced into electrical signals transmitted to the brain. Excessive noise exposure overwhelms the cochlea’s ability to reverse these changes, causing noise-induced hearing loss (NIHL). The Centers for Disease Control and Prevention state that NIHL is the only completely preventable type of hearing loss. What is the evidence-based safe noise exposure level to prevent NIHL? The National Institute for Occupational Safety and Health (NIOSH) recommended exposure level (REL), 85 dBA, does not prevent NIHL. Occupational exposures are calculated for 8 hours/day, 240 days/year, for 40 years. To calculate the noise exposure level to prevent NIHL in the public, 70 dB for 24 hours (Leq(24) = 70), the Environmental Protection Agency (EPA) adjusted the REL for 24 hours/day, 365 days/year exposure. The actual safe noise exposure must be lower than 70 dB because 1) the EPA did not adjust for lifetime noise exposure, 2) NIOSH based its REL on limited-frequency pure tone audiometry, an insensitive measure of auditory damage, and 3) non-occupational noise exposure has increased. The safe noise level may be as low as 55 dBA, the effective quiet level required for humans to recover from noise-induced temporary threshold shift.

Environmental Impacts of Automotive Air Conditioning System Maintenance Practices Embraced by Service Technicians in Niger State, Nigeria

This research work examined the environmental impacts of automotive air conditioning system maintenance practices embraced by service technician in Niger State, Nigeria. The study sought out the problem associated with automotive air conditioning maintenance practices and the way of improving automotive air conditioning system maintenance practices by automotive air conditioning services technicians in Niger State. Two research questions and two hypotheses guided the study. A descriptive survey research designed was adopted for the study. A total population of 155 respondents comprises of 97 highly experienced registered air conditioning service technicians and 58 moderately experienced registered air conditioning service technicians in Niger State. The respondents were selected according to the year of service, which was 1-14 years for moderately experienced and 15 above for highly experienced service technicians. Due to manageable sizes of the respondents, the entire population was used i.e no sampling techniques was utilized for the study. A structured questionnaire title “Automotive Air Conditioning System Maintenance Practices Questionnaire” was faced validated by three experts (one lecturer from Department of Industrial and Technology Education, Federal University of Technology Minna, one expert from Ministry of Environment Niger State and one expert from Ministry of Health Niger State). The questionnaire was pilot tested using 30 automotive air conditioning service technicians from Abuja. The data collected were analyzed using Cronbach Alpha Statistics and its yielded to 0.71 reliability coefficient. Mean and standard deviation were used to analyze the research questions and hypotheses were tested at 0.05 level of significance using z-test statistics. The numerical values obtained from the responses of the respondents were tabulated and analyzed using statistical package for social science (SPSS) version 23. The findings among other revealed that inhalation of concentration refrigerant vapour is dangerous and can be fatal, exposure to level of fluorocarbons above recommended exposure levels can results in loss of concentration and drowsiness, inhaling refrigerants adds to the effect of chronic illness. It is recommended amongst other that hazardous automotive air conditioning waste generated by automotive service technicians’ shops should always be removed by licensed personnel under the supervision of environmental agencies. Manufacturer instructions on refrigerants should be followed by technicians.

The impact of urban environmental exposures on health: An assessment of the attributable mortality burden in Sao Paulo city, Brazil

BackgroundCurrently, more than half of the global population lives in cities. Contemporary urban planning practices result in environmental risk factors (e.g. air pollution, noise, lack of green space, excess heat) that put health and well-being of city dwellers at risk and contribute to chronic diseases and premature death. Despite a growing body of evidence on adverse health impacts related to current urban and transport planning practices, especially for cities in the Global North, not much is known about associated health impacts in South American cities. Therefore, we estimated the mortality burden attributable to breaching internationally-recommended or locally-preferable exposure levels of urban planning related environmental exposures in Sao Paulo, Brazil. MethodsWe carried out a health impact assessment study, following the comparative risk assessment framework, to assess preventable mortality impacts of breaching exposure recommendations for air pollution, green spaces and temperature at the census tract (CT) level (n = 18,363). We also assessed the distribution thereof by socioeconomic vulnerability. ResultsWe estimated that annually 11,372 (95% CI: 7921; 15,910) attributable deaths could be prevented by complying with recommended exposure levels. The largest proportion of preventable mortality was due to breaching air pollution limits (i.e. 8409 attributable deaths), followed by insufficient green space (i.e. 2593), and excess heat (i.e. 370). Adverse health impacts were larger in CTs of lower socioeconomic vulnerability, due to demographic profile, traffic density and residential area configurations. DiscussionNot complying with the health limits for air pollution, green space and temperature exposures resulted in a considerable preventable mortality burden (i.e. 17% of total expected deaths) in Sao Paulo. This burden can be reduced by improving current urban and transport planning practices.

Personal Exposure to Fine Particles (PM2.5) in Northwest Africa: Case of the Urban City of Bamako in Mali.

Personal exposure to particulate matter (PM) from anthropogenic activities is a major concern in African countries, including Mali. However, knowledge of particulates is scant. This study was undertaken to characterize personal exposure to PM2.5 microns or less in diameter (PM2.5) in the city of Bamako in Mali. The exposure to PM2.5, through daily activities was observed from September 2020 to February 2021. Participants wore palm-sized optical PM2.5 sensors on their chest during their daily activities. The exposure levels in four different groups of residents were investigated in relation to their daily activities. The variation in PM2.5 concentration was measured during different activities in different microenvironments, and the main sources of exposure were identified. The highest average 10 min concentrations were observed at home and in bedrooms, while the participants were using specific products typically used in Africa, Asia, and South America that included insecticides (IST; 999 µg/m3) and incense (ICS; 145 µg/m3), followed by traffic (216 µg/m3) and cooking (150 µg/m3). The lowest average 10 min concentrations were also observed in the same microenvironment lacking IST or ICS (≤14 µg/m3). With no use of specific products, office workers and students were the least exposed, and drivers and cooks were the most exposed. The concentrations are up to 7.5 and 3 times higher than the World Health Organization’s yearly and daily recommended exposure levels, respectively, indicating the need to promptly elaborate and apply effective mitigation strategies to improve air quality and protect public health. This study highlights the importance of indoor air pollution sources related to culture and confirms previous studies on urban outdoor air pollution sources, especially in developing countries. The findings could be applied to cities other than Bamako, as similar practices and lifestyles are common in different cultures.

The sound of drumming for traditional Taiko drumming and lion dance

Drumming is an important part of traditional performances in different cultures around the world. Taiko drumming, the drumming with lion dance and the related instruments for traditional cultural performances, can produce sounds loud enough to potentially damage the hearing. In this study the sound track and the sound levels of a typical Taiko performance in Hiroshima, traditional lion dance performances with drumming and other accompanying musical instruments in a school and a shopping mall in Singapore, as well as a traditional drumming performance in a school concert hall were recorded and analyzed to assess the potential sound exposure. For both lion dance performances, the A-weighted equivalent sound pressure level with slow time response (LASeq) was found to be below 87dBA and a half an hour performance was not likely to infringe the The National Institute for Occupational Safety and Health (NIOSH) standard. On the other hand, the half an hour of Taiko drumming performance may hit the recommended exposure level (REL) from NIOSH with LASeq of 97dBA. Both the Taiko drumming and lion dance performances were found to have significant low frequency content with the C-weighted sound levels higher than the corresponding A-weighted sound levels. The idea of using a calibrated smartphone for assessing the sound levels of drumming and traditional lion dance performance is that it can be carried out at any time and any location with the encountering of a drumming performance without the need for pre-preparation of sound measurement equipment.

Bioaerosol Exposure and in vitro Activation of Toll-like Receptors in a Norwegian Waste Sorting Plant

BackgroundThe global shift toward greener societies demands new technologies and work operations in the waste-management sector. However, progressive industrial methods do not necessarily consider workers’ health. This study characterized workers' exposure to bioaerosols and investigated the bioaerosols’ potential to engage the immune system in vitro. MethodsFull shift personal aerosol sampling was conducted over three consecutive days. Dust load was analyzed by gravimetry, fungal and actinobacterial spores were analyzed by scanning electron microscopy, and endotoxin by limulus amebocyte lysate (LAL) assay. In vitro exposure of HEK cells to airborne dust samples was used to investigate the potential of inducing an inflammatory reaction. ResultsThe total dust exposure level exceeded the recommended occupational exposure limit (OEL) of 5.0 mg/m3 in 3 out of 15 samples. The inhalable endotoxin level exceeded the recommended exposure level by a 7-fold, whereas the fungal spore level exceeded the recommended exposure level by an 11-fold. Actinobacterial spores were identified in 8 out of 14 samples. In vitro experiments revealed significant TLR2 activation in 9 out of 14 samples vs. significant TLR4 activation in all samples. ConclusionThe present study showed that the dust samples contained potentially health-impairing endotoxin, fungi, and actinobacterial levels. Furthermore, the sampled dust contained microbial components capable of inducing TLR activation and thus have the potential to evoke an inflammatory response in exposed individuals.

ASSESSMENT OF NOISE IMPACT OF AIRCRAFT OPERATIONS AROUND PODGORICA AIRPORT

Abstract:This paper analyses impact of aircraft noise on community around Podgorica Airport, Montenegro. The airport is located 12 km from the city centre of the Montenegro capital, Podgorica. It served 1.3 million passengers and 7.5 thousand operations in 2019. The noise impact assessment is conducted in IMPACT web-based modelling platform using the distribution of operations by aircraft types, time of the day, and radar tracks for the busiest day (August 15) in 2019. Noise contours are assessed for Lden and Lnight indicators. They were merged with the Global Human Settlement Layer to assess the number of people exposed to different noise levels. In addition, based on the World Health Organization recommended exposure levels related to their health implications, the percentages of the population highly annoyed and highly sleep-disturbed are estimated. Furthermore, facilities of public importance (schools, hospitals, churches, etc.) are assessed against compatibility with the requirements set for the Zones with increased noise protection in national regulations. The results show that the exposure of community around Podgorica Airport to aircraft noise is still not a serious issue. The near vicinity of the airport is industrial zone and the number of people highly annoyed by noise is approximately 3.2% of the total city population. Nevertheless, it is crucial to draw attention to planners to preserve airport neighbourhood from potential inhabiting, to avoid problems that some airports in the region are facing nowadays.

The impact of urban and transport planning on health: Assessment of the attributable mortality burden in Madrid and Barcelona and its distribution by socioeconomic status

BackgroundThe population living in urban areas is growing rapidly. The level of exposure to adverse environmental factors is detrimental to human health and is directly related to urban and transport planning practices. ObjectiveTo estimate the premature mortality burden of non-compliance with international exposure guidelines for air pollution, noise, access to green space and heat for Barcelona and Madrid (Spain), and its distribution among the population by the socioeconomic status (SES). MethodsThe Urban and TranspOrt planning Health Impact Assessment (UTOPHIA) tool was applied and the attributable premature mortality due to non-compliance with recommended exposure levels was estimated. The distribution of the attributable mortality burden among the population by SES was investigated through Generalized Additive Models (GAMs) adjusting for spatial autocorrelation and a cluster analysis was performed to identify attributable mortality hot spots. ResultsAnnually, 7.1% and 3.4% of premature mortality in Barcelona and Madrid, respectively, could be attributed to non-compliance with the international exposure recommendations for air pollution, noise, heat and access to green space. In addition, analysis by SES showed that in Barcelona lower SES areas had an overall greater attributable mortality rate, while in Madrid, the distribution of the attributable mortality burden by SES varied by exposure. ConclusionThis study shows the impact of environmental exposures on mortality and highlights the importance of taking integrated actions when designing cities considering the health impacts, but also the specificities of each city such as the socio-demographic context. Moreover, the high precision scale of the analysis enables the identification of environmental hazards and mortality hot spots providing a powerful tool to support priority-setting and guide policymakers towards a healthy, sustainable and just city for all of their residents.

Assessment of the knowledge, attitude, and practice of using hair-smoothing products among women in Saudi Arabia

Background: Hair-smoothing products have been developed by the cosmetic industry, targeting the popular desire among women for beautification. The products are also used as a treatment for hair. All hair-smoothing products contain different levels of formaldehyde, which is classified as a carcinogen by the World Health Organization. Purpose: This study aimed to assess the knowledge, attitude, and practice of using hair-smoothing products among women in Saudi Arabia, as well as identifying common side effects of their use. Methods: A cross-sectional study was conducted in 2020 in Saudi Arabia. Self-administered questionnaires were distributed to more than 1600 women, administered in the Arabic language using paper and an online survey. Results: Only 35% of the participants had previously used hair treatments, whereas 24% of the participants identified formaldehyde as a carcinogen. Close to two-thirds (59%) of the participants used hair treatments to facilitate management of their hair. About one-third (35%) of participants read the instructions for hair treatments before their use. The main symptom participants mentioned related to formaldehyde exposure was hair loss (34%). The majority of users (71%) use personal protective equipment during their use of hair-smoothing products. Conclusion: Our study demonstrated low levels of knowledge, a number of misconceptions, and faulty practices. Women must be made aware of the risks of some hair-straightening products that contain large concentrations of formaldehyde exceeding the recommended exposure levels. Therefore, we recommend raising the overall general public knowledge and awareness of hair-straightening products by establishing marketing campaigns and spreading knowledge through social media.

Indoor air quality in rural Southwestern Uganda: particulate matter, heavy metals and carbon monoxide in kitchens using charcoal fuel in Mbarara Municipality

The use of biomass energy over open fires in sub-Saharan Africa is rampant yet it is associated with air pollution. Information on the contribution of common biomass like charcoal to indoor air pollution in Uganda is scarce; therefore, kitchen-indoor air in charcoal fueled kitchens was characterized for fine particulate matter (PM2.5), heavy metals and carbon monoxide content in Mbarara Municipality Western Uganda. PM2.5 was measured using University of California Berkeley Particle and Temperature Sensor (UCB-PATS), heavy metals were determined using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and carbon monoxide was measured using a portable, battery-operated, data-logging Drager Pac 7000. In the kitchens assessed, the mean 24-h concentration for PM2.5 was 0.449 mg/m3 in the wet season and 0.526 mg/m3 in the dry season; CO was 41.52 ppm, and all concentrations were higher than the World Health Organization 24-h Air Quality Guideline for PM2.5 of 0.024 mg/m3 and CO of 6.340 ppm. Heavy metals in particulate matter were in concentration ranges of 1.012–9.820 μg/m3 Fe, 0.012–0.092 μg/m3 Cr, 0.060–10.750 μg/m3 Zn, 0.048–0.300 μg/m3 Cu, 0.004–0.052 μg/m3 Pb and ND—0.004 μg/m3 Cd. All mean metal concentrations were lower than recommended exposure levels by EPA although chronic exposure is a risk to health. Kitchen ventilation and size were found to significantly influence indoor pollutant levels; charcoal fuel significantly contributed to indoor air pollution and is therefore a risk factor to human health.

Predicting airborne coronavirus inactivation by far-UVC in populated rooms using a high-fidelity coupled radiation-CFD model

There are increased risks of contracting COVID-19 in hospitals and long-term care facilities, particularly for vulnerable groups. In these environments aerosolised coronavirus released through breathing increases the chance of spreading the disease. To reduce aerosol transmissions, the use of low dose far-UVC lighting to disinfect in-room air has been proposed. Unlike typical UVC, which has been used to kill microorganisms for decades but is carcinogenic and cataractogenic, recent evidence has shown that far-UVC is safe to use around humans. A high-fidelity, fully-coupled radiation transport and fluid dynamics model has been developed to quantify disinfection rates within a typical ventilated room. The model shows that disinfection rates are increased by a further 50-85% when using far-UVC within currently recommended exposure levels compared to the room’s ventilation alone. With these magnitudes of reduction, far-UVC lighting could be employed to mitigate SARS-CoV-2 transmission before the onset of future waves, or the start of winter when risks of infection are higher. This is particularly significant in poorly-ventilated spaces where other means of reduction are not practical, in addition social distancing can be reduced without increasing the risk.

Repeated Noise Exposure Does Not Reach Hazardous Levels During Total Joint Arthroplasty.

Noise exposure is an occupational health concern for certain professions, especially military servicemembers and those using power tools on a regular basis. The purpose of this study was to quantify noise exposure during total hip arthroplasty (THA) and total knee arthroplasty (TKA) cases compared to the recommended standard for occupational noise exposure. A sound level meter was used to record cumulative and peak noise exposure levels in 10 primary THA and 10 primary TKA surgeries, as well as 10 arthroscopy cases as controls. Measurements at the distance of the surgeon were taken in all cases. In TKA cases, measurements were taken at 3feet and 8feet from the surgeon, to simulate the position of the anesthetist and circulating nurse, respectively. Time-weighted average was significantly higher in THA (64.7±5.2dB) and TKA (64.5±6.8dB) as compared to arthroscopic cases (51.1±7.5dB, P<0.001) and higher at the distance of the surgeon (64.5±6.8dB) compared to the anesthetist (52.9±3.8dB) and the circulating nurse (54.8±11.2dB, P=0.006). However, time-weighted average was below the recommended exposure level of 85dB for all arthroplasty cases. Peak levels did not differ significantly between surgery type or staff role, and no values above the ceiling limit of 140dB were recorded. Surgeon's daily noise dose percentage per case was 1.78% for THA and 2.04% for TKA. Noise exposure in THA and TKA was higher than arthroscopic cases but did not exceed occupational standards. A daily dose percentage of approximately 2% per case indicates that repeated noise exposure likely does not reach hazardous levels in modern arthroplasty practice.