Average Exposure Levels Research Articles

Association between Exposure to Noise and Sleep and Mental Health Outcomes in a Nationally-Representative Sample of U.S. Adolescents

Background: In 1974, the U.S. Environmental Protection Agency (U.S. EPA) identified an equivalent 24-hour continuous average noise exposure level (LAeq, 24h) of < 55 A-weighted decibels to protect public health with an adequate margin of safety. To date, however, limited U.S.-based research has evaluated the relationship between noise pollution and health. We help fill this gap using data from a nationally-representative sample of U.S. adolescents.Methods: We used a cross-sectional geospatial sound model to estimate noise exposure at the block group level. We dichotomized noise as high (LAeq, 24h ≥ 55 dB) versus low (LAeq, 24h <55 dB). The National Comorbidity Survey Adolescent Supplement, conducted between 2001-2004 and including several self-reported sleep outcomes and DSM-IV disorder diagnoses, provided our study population. We evaluated the association between noise and sleep and mental health using doubly-robust targeted minimum loss-based estimation and propensity score matching to account for potential confounders, including air pollution.Results: The study included 4,508 urban-dwelling adolescents aged 13-18. Controlling for numerous adolescent, household, and environmental covariates, living in a high- versus low-noise census block-group was associated with later bedtimes on both weeknights and weekend nights (risk difference [RD]: 0.41 hours, 95% CI: -0.01, 0.83, and RD: 0.61 hours, 95% CI: 0.38, 0.84, respectively). We found no association with total number of hours slept. Further, we found that living in a high- versus low-noise census block-group was associated with 69% increased odds of an anxiety or depressive disorder (odds ratio [OR]: 1.69, 95% CI: 1.13, 2.25) and 79% increased odds of substance use disorder (OR: 1.79, 95% CI: 0.91, 2.66); we found no similar associations with behavioral disorders.Conclusion: We found evidence that noise exceeding the U.S. EPA threshold may hold adverse sleep and mental health consequences for U.S. adolescents.

Postnatal Exposure of PM10 and Autistic Behaviours among Children: The Mothers and Children's Environmental Health (MOCEH) Study

Background/AimEnvironmental factors may play a role in the development of neurodevelopment and some studies have shown that ambient air pollution is associated with the autistic behaviours. The study was designed to investigate the impact of outdoor air pollution on autistic behaviours among children at 4, 5 years of age in Korea by using MOCEH cohort study's data.MethodsThis study is a part of the Mothers and Children's Environmental Health (MOCEH) study, a Korean multi-center prospective birth cohort study initiated in 2006. After delivery, children were followed up at 48 and 60 months of age. Average exposure level of particulate matter (PM10) were estimated using the inverse distance weighting (IDW) method from prenatal period to postnatal period. A total of 322 mother-child pairs were included. Autistic behaviours were assessed using the Social Responsiveness Scale (SRS) at 4, 5 years of age. We also examined the result stratified by sex of the children.ResultsThe average levels of PM10 during pregnancy and 3 years of age were 54.07μg/m3 and 50.08μg/m3 each. In a multiple linear regression model, although we couldn’t find significant positive relationship between exposure of PM10 in children, we found that PM10 at 3 years of age was associated with increased scores of SRS T-scores at 5 years of age in boys. (β=0.36, 95% confidence interval [CI]: 0.05,0.66) However, there was no significant positive association in girls.ConclusionsIn conclusions, postnatal exposure of PM10 is associated with the autistic behaviours, in boys at 4, 5 years of age. Further study on the other air pollutants effects to autistic behaviours in children is recommended.

STATISTICAL APPROACH FOR HUMAN ELECTROMAGNETIC EXPOSURE ASSESSMENT IN FUTURE WIRELESS ATTO-CELL NETWORKS.

In this article, we study human electromagnetic exposure to the radiation of an ultra dense network of nodes integrated in a floor denoted as ATTO-cell floor, or ATTO-floor. ATTO-cells are a prospective 5 G wireless networking technology, in which humans are exposed by several interfering sources. To numerically estimate this exposure we propose a statistical approach based on a set of finite difference time domain simulations. It accounts for variations of antenna phases and makes use of a large number of exposure evaluations, based on a relatively low number of required simulations. The exposure was expressed in peak-spatial 10-g SAR average (psSAR10g). The results show an average exposure level of ~4.9 mW/kg and reaching 7.6 mW/kg in 5% of cases. The maximum psSAR10g value found in the studied numerical setup equals around 21.2 mW/kg. Influence of the simulated ATTO-floor size on the resulting exposure was examined. All obtained exposure levels are far below 4 W/kg ICNIRP basic restriction for general public in limbs (and 20 W/kg basic restriction for occupational exposure), which makes ATTO-floor a potential low-exposure 5 G candidate.

A Systematic Review of Full-Shift, Noise Exposure Levels Among Construction Workers: Are We Improving?

Construction industry workers are at high risk of occupational noise exposure. Although regulations and guidelines for this industry specify the use of noise controls, workers continue to be exposed to hazardous noise levels. The objectives of this study were (i) to collate and describe full-shift noise exposure experienced by construction workers; (ii) to review trends in full-shift exposure over time and between countries; and (iii) to identify any occupational categories within the construction industries that have higher levels of exposure. Of the 1171 studies found using key terms, 25 contained noise exposure measurements that met our inclusion criteria. Sample populations were predominantly from large construction sites and primarily comprised occupations known to engage in noisy workplace activities. Studies spanned over 36 years with all having average full-shift noise exposure over 85 A-weighted decibels (dBA). No time trend in full-shift noise exposure levels for construction workers was observed. Construction workers in the subgroup occupations of mason, sheet metal workers, carpenters, concrete workers, and operating engineers consistently had mean LAeq,8h over the 85 dBA limit. Studies spanning 36 years in 10 countries consistently show construction workers have been exposed to hazardous noise levels. There has been no significant change over time of the average full-shift exposure levels of construction workers, including in all occupational subgroups except iron-workers. Some variability in full-shift measures is due to sampling methods and population characteristics and to a lesser extent, methods used to derive exposure levels.

Study on sandstorm PM10 exposure assessment in the large-scale region: a case study in Inner Mongolia.

The current exposure-effect curves describing sandstorm PM10 exposure and the health effects are drawn roughly by the outdoor concentration (OC), which ignored the exposure levels of people's practical activity sites. The main objective of this work is to develop a novel approach to quantify human PM10 exposure by their socio-categorized micro-environment activities-time weighed (SCMEATW) in strong sandstorm period, which can be used to assess the exposure profiles in the large-scale region. Types of people's SCMEATW were obtained by questionnaire investigation. Different types of representatives were trackly recorded during the big sandstorm. The average exposure levels were estimated by SCMEATW. Furthermore, the geographic information system (GIS) technique was taken not only to simulate the outdoor concentration spatially but also to create human exposure outlines in a visualized map simultaneously, which could help to understand the risk to different types of people. Additionally, exposure-response curves describing the acute outpatient rate odds by sandstorm were formed by SCMEATW, and the differences between SCMEATW and OC were compared. Results indicated that acute outpatient rate odds had relationships with PM10 exposure from SCMEATW, with a level less than that of OC. Some types of people, such as herdsmen and those people walking outdoors during a strong sandstorm, have more risk than office men. Our findings provide more understanding of human practical activities on their exposure levels; they especially provide a tool to understand sandstorm PM10 exposure in large scale spatially, which might help to perform the different categories population's risk assessment regionally.

Extremely Low Frequency-Magnetic Field (ELF-MF) Exposure Characteristics among Semiconductor Workers.

We assessed the exposure of semiconductor workers to extremely low frequency-magnetic fields (ELF-MF) and identified job characteristics affecting ELF-MF exposure. These were demonstrated by assessing the exposure of 117 workers involved in wafer fabrication (fab) and chip packaging wearing personal dosimeters for a full shift. A portable device was used to monitor ELF-MF in high temporal resolution. All measurements were categorized by operation, job and working activity during working time. ELF-MF exposure of workers were classified based on the quartiles of ELF-MF distribution. The average levels of ELF-MF exposure were 0.56 µT for fab workers, 0.59 µT for chip packaging workers and 0.89 µT for electrical engineers, respectively. Exposure to ELF-MF differed among types of factory, operation, job and activity. Workers engaged in the diffusion and chip testing activities showed the highest ELF-MF exposure. The ELF-MF exposures of process operators were found to be higher than those of maintenance engineers, although peak exposure and/or patterns varied. The groups with the highest quartile ELF-MF exposure level are operators in diffusion, ion implantation, module and testing operations, and maintenance engineers in diffusion, module and testing operations. In conclusion, ELF-MF exposure among workers can be substantially affected by the type of operation and job, and the activity or location.

Dip coating of air purifier ceramic honeycombs with photocatalytic TiO2 nanoparticles: A case study for occupational exposure

Nanoscale TiO2 (nTiO2) is manufactured in high volumes and is of potential concern in occupational health. Here, we measured workers exposure levels while ceramic honeycombs were dip coated with liquid photoactive nanoparticle suspension and dried with an air blade. The measured nTiO2 concentration levels were used to assess process specific emission rates using a convolution theorem and to calculate inhalation dose rates of deposited nTiO2 particles. Dip coating did not result in detectable release of particles but air blade drying released fine-sized TiO2 and nTiO2 particles. nTiO2 was found in pure nTiO2 agglomerates and as individual particles deposited onto background particles. Total particle emission rates were 420×109min−1, 1.33×109μm2min−1, and 3.5mgmin−1 respirable mass. During a continued repeated process, the average exposure level was 2.5×104cm−3, 30.3μm2cm−3, <116μgm−3 for particulate matter. The TiO2 average exposure level was 4.2μgm−3, which is well below the maximum recommended exposure limit of 300μgm−3 for nTiO2 proposed by the US National Institute for Occupational Safety and Health. During an 8-hour exposure, the observed concentrations would result in a lung deposited surface area of 4.3×10−3cm2g−1 of lung tissue and 13μg of TiO2 to the trachea-bronchi, and alveolar regions. The dose levels were well below the one hundredth of the no observed effect level (NOEL1/100) of 0.11cm2g−1 for granular biodurable particles and a daily no significant risk dose level of 44μgday−1. These emission rates can be used in a mass flow model to predict the impact of process emissions on personal and environmental exposure levels.

Study on the Sensitivity Indicators by Sandstorm PM10 Exposure

PM10 is one of the typical pollutants involved with sandstorm. More and more attentions on the sensitive bio-marks by PM10 exposure are attracted. This study is to probe the sensitivities indicators’ levels by sandstorm PM10 exposure. A cross-sectional study involving administration on a survey 150 residents in Erlianhaote was performed. PM10 concentrations collected on a daily basis from the local monitor stations from March to June, 2016 were employed as the daily environmental exposure levels (DEEL). Indicators of IGM, CRP, CC16, IL16, IGA, LGG, IGE and IL8 were assayed, as well as questionnaire for individual disease histories were done. Results indicated that PM10 exposure level was positively related to IGG, IGM, IGA, LGG and CRP, age was positively related to CRP and LGG, and history of cardiovascular disease was related to CRP by multi-factor line regression analysis. Further analysis revealed that levels of IGG (p<0.01) and IGM (p<0.05) increased in the group with PM10 DEEL exceeded 200 μg/m3, compared to the group with the average exposure levels less than 200 μg/m3; while levels of IGM (p<0.05), IGA (p<0.05), LGG (p<0.05) and CRP (p<0.01) were found higher in the group with PM10 DEEL exceed 300 μg/m3, compare to the group with the levels less than 300 μg/m3. Our findings suggest that sandstorm PM10 exposure might contribute to the changes of some immune and inflammation index. These findings provide clinical indicators for the sandstorm PM10 exposure and help to understand the risk of sandstorm pollution.

At-ear noise levels under the helmet: a field study on noise exposure of young motorcyclists

At-ear noise exposure assessments of motorcyclists, with the function of speed, would be unsafe as on-road data acquisition has certain constraints including the operations and portability of appropriate instrument. Currently, there are no standardized protocols and methods for measuring the noise under motorcycle helmets. Furthermore, standard permissible noise emission levels for commuter motorcyclists are also not defined. Therefore, this study was aimed to investigate the motorcycle noise exposure assessments in realistic environment among young riders. A personal dosimeter was utilized to calculate the daily noise exposure level (L Aeq , 8h) under three different standards including: OSHA-HC (Occupational Safety and Health Administration, Hearing Conservation), OSHA-PEL (Permissible Emission Level) and ACGIH/NIOSH (American Conference of Governmental Industrial Hygienists/ National Institute of Occupational Safety and Health). The study design consisted of noise assessment of riders (age range:19 to 25 years) at-ear under the open-face helmet in-realistic situation (main road to the motorway) motorcycling in dry weather conditions. Personal dosimeter results ( n =52) revealed the average noise exposure level of 93.64 dBA, 92.51 dBA, 95.29 dBA for OSHA-HC, OSHA-PEL and ACGIH/NIOSH respectively. The mean Time-Weighted Average (TWA) was 76.82 dBA, 75.69 dBA, 85.16 dBA for OSHAHC, OSHA-PEL and ACGIH/NIOSH respectively. Under the ACGIH and NIOSH standard, the TWA for motorcyclists is at hazardous limits, which requires further investigations associated with health effects on riders. Standardized methods and configurations should be set for assessing noise exposure related to the motorcycling. Keywords: Motorcycle noise, Wind noise, Dosimeter, OSHA, ACGIH

Diurnal variability of transportation noise exposure and cardiovascular mortality: A nationwide cohort study from Switzerland.

Most epidemiological noise studies consider 24 h average noise exposure levels. Our aim was to exploratively analyze the impact of noise exposure at different time windows during day and night on cardiovascular mortality. We generated Switzerland-wide exposure models for road traffic, railway and aircraft noise for different time windows for the year 2001. Combined noise source equivalent continuous sound levels (Leq) for different time windows at the most exposed façade were assigned to each of the 4.41 million Swiss National Cohort adult participants. Follow-up period was from 2000 to 2008. Hazard ratios (HR) of noise effects on various cardiovascular primary causes of death were computed by Cox regression models adjusted for potential confounders and NO2 levels. For most cardiovascular causes of death we obtained indications for a diurnal pattern. For ischemic heart disease the highest HR was observed for the core night hours from 01 h to 05 h (HR per standard deviation of Leq: 1.025, 95% CI: 1.016-1.034) and lower HR for the daytime 07 h to 19 h (1.018 [1.009-1.028]). Heart failure and daytime Leq yielded the highest HR (1.047 [1.027-1.068]). For acute cardiovascular diseases, nocturnal intermittent noise exposure tended to be more relevant than daytime exposure, whereas it was the opposite for chronic conditions such as heart failure most strongly associated with continuous daytime noise. This suggests that for acute diseases sleep is an important mediator for health consequences of transportation noise.

Combined Effect of Air Pollution and Secondhand Smoke on Neurodevelopment at 24 Months

Background/Aim: Neurodevelopment of infants have been associated with exposure to secondhand smoke (SHS) and air pollution (AP), respectively. There has been very few previous studies of combined effect of AP and SHS on early neurodevelopment. We aim to investigate the combined effect of AP and SHS prenatal exposure on neurodevelopment of infants at 24 months of age. Methods: We analyzed 721 mothers and their offspring from Korean multicenter birth cohort study: Mothers and Children Environmental Health (MOCEH). We measured maternal urinary cotinine to represent SHS exposure during pregnancy. Average exposure levels to PM10 (particulate matter&lt;10in diameter) and nitrogen dioxide during the entire pregnancy were estimated using the inverse distance weighting method. Infant’s mental developmental index (MDI) and psychomotor developmental index (PDI) were measured using the Bayley Scales of Infant Development at 24 months of age. General linear model was used to assess the relationship between combined exposure of AP and SHS and neurodevelopment. Results: MDI score of 24 months aged infants was associated with cotinine [β= -2.56, 95%confidence interval (CI): -4.58, -0.53] in mothers with early pregnancy urinary cotinine levels &gt;1.90 ng/ml. The MDI score of infant was more decreased in mothers exposed to both PM10 &gt;50 mg/m3 during pregnancy and high exposure of SHS [β= -2.85, 95%CI: -5.17, -0.54]. The negative association was reduced when children received breast milk up to 6 months [β= 0.06, 95%CI: -3.13, 3.24]. However, the combined effect was more pronounced in mothers with both GSTM1/GSTT1 null type on MDI [β= -8.17, 95%CI: -12.27, -4.06] and PDI [β= -3.65, 95% CI: -7.38, 0.08]. Conclusions: These findings suggest that maternal combined exposure to PM10 and SHS during pregnancy may result in delayed neurodevelopment in early childhood and propose its combined effects. The effect might be modified by genetic polymorphism and breastfeeding.

Dietary exposure to HCH and DDT congeners and their associated cancer risk based on Pakistani food consumption.

Dietary exposure to organochlorine pesticides such as hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT) congeners was assessed using diet study approach, and for this purpose, different food items were collected in August 2014. The levels of ∑(HCHs + DDTs) in different food groups were ranged from 2.57 to 206ngg-1, ww, with contamination order of fish > poultry > milk > vegetables > cereals > flour > fruits. In the present study, the ratios of β-HCH/∑HCH (0.19-0.40) were < 0.5, where the ratios of (DDE + DDD)/∑DDT (0.48-6.70 with mean value of 0.61) were > 0.5 demonstrated the recent and past inputs of HCH and DDT, respectively. The major contributing groups (6.3-70.3%) to total dietary intake of HCHs and DDTs were animal origin (fish, poultry, and milk), while the less contributing food groups (2-4.5%) were vegetarian origin (vegetables, cereals, flour, and fruits). Cancer risk was estimated for HCHs and DDTs ingested via local foodstuffs. On the basis of both average and high end (95th percentile) exposure levels, the HRs for HCHs and DDTs were found greater than one (safety limit), indicating a potential cancer risk for Pakistani people from life-time consumption of contaminated food items selected in this study. The congener-specific cancer risk was found in order of α-HCH > β-HCH > ∑DDT > γ-HCH > p,p'-DDE > p,p'-DDT. Graphical abstract ᅟ.

Examining the noisy life of the college musician: weeklong noise dosimetry of music and non-music activities

Objective: To examine the contribution of all daily activities, including non-music activities, to the overall noise exposure of college student musicians, and to compare their “noise lives” with those of non-musician college students. Design: Continuous week-long dosimetry measurements were collected on student musicians and non-musicians. During the measurement period, participants recorded their daily activities in journals. Study sample: 22 musicians and 40 non-musicians, all students (aged 18–24 years) at the University of Connecticut. Results: On every day of the week, musicians experienced significantly higher average exposure levels than did non-musicians. Nearly half (47%) of the musicians’ days exceeded a daily dose of 100%, compared with 10% of the non-musicians’ days. When the exposure due to music activities was removed, musicians still led noisier lives, largely due to participation in noisier social activities. For some musicians, non-music activities contributed a larger share of their total weekly noise exposure than did their music activities. Conclusions: Compared with their non-musician peers, college student musicians are at higher risk for noise-induced hearing loss (NIHL). On a weekly basis, non-music activities may pose a greater risk to some musicians than music activities. Thus, hearing health education for musicians should include information about the contribution of lifestyle factors outside of music to NIHL risk.

Personal light-at-night exposures and components of variability in two common shift work industries: uses and implications for future research.

Objectives Shift workers' increased risk of various adverse health outcomes has been linked to light-at-night (LAN) exposure, but few studies have measured LAN exposure in workplaces. To inform future research methods, this study aimed to (i) measure shift workers' exposures to LAN across industries, occupations, and work environments and (ii) assess components of variance across different exposure groupings and metrics. Methods Between October 2015 and March 2016, 152 personal full-shift measurements were collected from 102 night shift workers in emergency health services (paramedics, dispatchers) and healthcare industries (nurses, care aides, security guards, unit clerks, and laboratory, pharmacy, and respiratory therapy staff) in the province of British Columbia, Canada. Descriptive and variance component analyses were conducted for the 23:00-05:00 period to characterize exposures using multiple metrics of potential biological relevance (median lux, 90 thpercentile lux, sum of minutes ≥30 lux, and sum of minutes ≥100 lux). Results Average exposure levels were highest in the healthcare industry. By occupation, laboratory workers and care aides displayed the highest and emergency dispatch officers displayed the lowest levels for all LAN exposure metrics. Between-group variance was large relative to within-group variance for all exposure groupings and metrics, and increased as grouping specificity increased (moving from industry to occupation). Conclusions Results from this study suggest that high-level grouping schemes may provide a simple yet effective way of characterizing individual LAN exposures in epidemiological studies of shift work. Ongoing measurement of LAN exposures and assessment of exposure variability is needed in future studies of shift workers as a means to increase sampling efficiency, reduce measurement error, and maximize researchers' ability to detect relationships where they exist.

Occupational noise exposure and risk of hypertension in an industrial workforce.

Community noise exposure has been shown to increase the risk of hypertension; however, the relationship between occupational noise exposure and hypertension is less clear. Using an inception cohort of workers in a specialty metals manufacturing company, we retrospectively assessed occupational noise exposure, hearing acuity, and incident hypertension diagnoses using administrative datasets. Time-weighted average noise exposure levels were assigned to employees based on their job histories. Cox proportional hazards models were performed to determine the association of noise exposure with risk of incident hypertension. The adjusted hazard ratio (HR) of incident hypertension did not significantly differ between groups by cumulative continuous or categorized noise exposure metric. We found no increased risk of incident hypertension with exposure to occupational noise among workers. Further assessment examining workers' use of hearing protection devices is warranted.

JP8 exposure and neurocognitive performance among US Air Force personnel

Petroleum-based fuels such as jet propellant (JP) 4, JP5, JP8, and jet A1 (JetA) are among the most common occupational chemical exposures encountered by military and civilian workforces. Although acute toxicity following high-level exposures to JP8 and similar chemical mixtures has been reported, the relationship between persistent low-level occupational exposures to jet fuels and both acute and longer-term central nervous system (CNS) function has been comparatively less well characterized. This paper describes results of neurocognitive assessments acquired repeatedly across a work week study design (Friday to Friday) as part of the Occupational JP8 Exposure Neuroepidemiology Study (OJENES) involving U.S. Air Force (AF) personnel with varying levels of exposure to jet fuel (JP8). JP8 exposure levels were quantified using both personal air monitoring and urinary biomarkers of exposure. Neurocognitive performance was evaluated using an objective, standardized battery of tests. No significant associations with neurocognitive performances were observed between individuals having regular contact and those with minimal/no direct contact with JP8 (measured by average work week levels of personal breathing zone exposure). Also, no significant findings were noted between repeated measures of absorbed dose (multi-day pre-shift urinary 1- and 2-naphthol) and reduced proficiency on neurocognitive tasks across the work week. Results suggest that occupational exposure to lower (than regulated standards) levels of JP8 do not appear to be associated with acute, measurable differences or changes in neurocognitive performance.

Human exposure to power frequency magnetic fields up to 7.6 mT: An integrated EEG/fMRI study.

We assessed the effects of power-line frequency (60 Hz in North America) magnetic fields (MF) in humans using simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). Twenty-five participants were enrolled in a pseudo-double-blind experiment involving "real" or "sham" exposure to sinusoidal 60 Hz MF exposures delivered using the gradient coil of an MRI scanner following two conditions: (i) 10 s exposures at 3 mT (10 repetitions); (ii) 2 s exposures at 7.6 mT (100 repetitions). Occipital EEG spectral power was computed in the alpha range (8-12 Hz, reportedly the most sensitive to MF exposure in the literature) with/without exposure. Brain functional activation was studied using fMRI blood oxygen level-dependent (BOLD, inversely correlated with EEG alpha power) maps. No significant effects were detected on occipital EEG alpha power during or post-exposure for any exposure condition. Consistent with EEG results, no effects were observed on fMRI BOLD maps in any brain region. Our results suggest that acute exposure (2-10 s) to 60 Hz MF from 3 to 7.6 mT (30,000 to 76,000 times higher than average public exposure levels for 60 Hz MF) does not induce detectable changes in EEG or BOLD signals. Combined with previous findings in which effects were observed on the BOLD signal after 1 h exposure to 3 mT, 60 Hz MF, this suggests that MF exposure in the low mT range (<10 mT) might require prolonged durations of exposure to induce detectable effects. Bioelectromagnetics. 38:425-435, 2017. © 2017 Wiley Periodicals, Inc.

Negative and Positive Emotion Responses to Daily School Problems: Links to Internalizing and Externalizing Symptoms.

Examining emotion reactivity and recovery following minor problems in daily life can deepen our understanding of how stress affects child mental health. This study assessed children's immediate and delayed emotion responses to daily problems at school, and examined their correlations with psychological symptoms. On 5 consecutive weekdays, 83 fifth graders (M=10.91years, SD=0.53, 51% female) completed brief diary forms 5 times per day, providing repeated ratings of school problems and emotions. They also completed a one-time questionnaire about symptoms of depression, and parents and teachers rated child internalizing and externalizing problems. Using multilevel modeling techniques, we assessed within-person daily associations between school problems and negative and positive emotion at school and again at bedtime. On days when children experienced more school problems, they reported more negative emotion and less positive emotion at school, and at bedtime. There were reliable individual differences in emotion reactivity and recovery. Individual-level indices of emotion responses derived from multilevel models were correlated with child psychological symptoms. Children who showed more negative emotion reactivity reported more depressive symptoms. Multiple informants described fewer internalizing problems among children who showed better recovery by bedtime, even after controlling for children's average levels of exposure to school problems. Diary methods can extend our understanding of the links between daily stress, emotions and child mental health. Recovery following stressful events may be an important target of research and intervention for child internalizing problems.

What is a safe noise exposure level for the public?

What is a safe noise exposure level for the public? This question should underlie basic and applied research on the effects of sound on humans, and regulatory efforts to control public noise exposure. The safe public noise exposure level cannot be an unadjusted occupational standard. Unlike other occupational exposures, noise exposure continues outside the workplace. Occupational limits must be adjusted for increased exposure time, from 8 to 24 hours daily, 240 workdays to 365 days annually, and from 40 work years to the entire lifespan. Recommended safe noise exposure levels depend on which adverse noise effect is being considered. To prevent hearing loss, the U.S. Environmental Protection Agency (EPA) adjusted the U.S. occupational recommended exposure level of 85 A-weighted decibels for additional exposure time to calculate a 70 decibel time weighted average (TWA) exposure level. EPA did not adjust for lifespan years so the correct safe exposure level is likely lower. The World Health Organization (WHO...

Development of radiation shield providing medical support for radioactive disaster in computer awareness analysis convergence-based

Experts expect that even though peaceful use of nuclear power including nuclear power plant is less likely to contribute to average annual radiation exposure level, once accidents occur, it will spell a disaster. This paper is to manufacture a bismuth eco-friendly radiation shield which does not contain lead for providing medical support when national disaster and radioactive accident occur and compare and evaluate the characteristics of the shield and the definition of image by using glass dosimeter and finally to assess its usability. The fact that bismuth radiation shield with 0.5 mm and lead radiation shield with 0.5 mm showed an equal percentage of efficiency is showing that bismuth is suitable as a eco-friendly material replacing lead in the field of medical radiation. This result implies that the eco-friendly radiation shield which is lighter than lead radiation shield can be utilized in the field of medical radiation as a radiation shield decreasing radiation exposure level. It is advised to develop a light weight and eco-friendly radiation shield to reduce radiation exposure level in the field of medical radiation and to obtain optimal medical image.