Personal Exposure Levels Research Articles

Respiratory Impairment and Personal Respirable Dust Exposure among the Underground and Open Cast Gold Miners in Tanzania.

Background:Mining is one of the most hazardous sectors to work in because it predisposes workers to various hazards including dust. Exposure to dust is inevitable in the mines because the process of extracting gold involves breaking rocks. This dust can penetrate up to the alveoli of the pulmonary system and cause respiratory impairment.Objectives:To determine respiratory impairment, personal respirable dust exposure levels and associated factors among miners in a gold mine in Tanzania.Methods:Cross-sectional study design, employing questionnaire, was used for data collection on respiratory symptoms. Lung functions were measured using spirometry. Personal respirable dust exposure was collected from similar exposure groups using air sampling pumps. A simple random sampling technique was used to select 112 participants of the study. Data analysis was done using SPSS computer software version 20.0.Results:The overall geometric mean (GM) of respirable dust was 0.26 mg/m3 (GSD = 0.32) over a mean sampling time of 8 hours (with a range between 7–11 hours). The GM of respirable dust for underground workers was significantly higher (0.41 ± 0.28 mg/m3) compared to the open pit workers (0.17 ± 0.23 mg/m3) with p < 0.01. For underground workers, the GM of respirable dust was the highest among the bogger operators at 0.53 mg/m3 (GSD = 0.27). For open pit workers, the highest GM of respirable dust was found among the quality controllers at 0.39 mg/m3 (GSD = 0.18). Respiratory symptoms were phlegm (49.1%), breathlessness (42.9%), cough (37.5%), wheezing (18.8%) and chest tightness (10.7%). Cigarette smokers were more likely to suffer from breathlessness than nonsmokers. The prevalence of airflow obstruction (FEV1/FVC < 0.7) was 1.9%; whereas, the prevalence of lung restriction was 8.8%. The study established that age, smoking habit and previous exposure to dust could not predict lung function impairment.Conclusion:Despite levels of respirable dust exposure being below the recommended occupational exposure limits, the prevalence of respiratory symptoms was still found to be high among the studied gold miners. This calls for a need to conduct further studies on quartz content of the respirable dust.

Short-term transcriptome and microRNAs responses to exposure to different air pollutants in two population studies

Diesel vehicle emissions are the major source of genotoxic compounds in ambient air from urban areas. These pollutants are linked to risks of cardiovascular diseases, lung cancer, respiratory infections and adverse neurological effects. Biological events associated with exposure to some air pollutants are widely unknown but applying omics techniques may help to identify the molecular processes that link exposure to disease risk. Most data on health risks are related to long-term exposure, so the aim of this study is to investigate the impact of short-term exposure (two hours) to air pollutants on the blood transcriptome and microRNA expression levels.We analyzed transcriptomics and microRNA expression using microarray technology on blood samples from volunteers participating in studies in London, the Oxford Street cohort, and, in Barcelona, the TAPAS cohort. Personal exposure levels measurements of particulate matter (PM10, PM2.5), ultrafine particles (UFPC), nitrogen oxides (NO2, NO and NOx), black carbon (BC) and carbon oxides (CO and CO2) were registered for each volunteer. Associations between air pollutant levels and gene/microRNA expression were evaluated using multivariate normal models (MVN).MVN-models identified compound-specific expression of blood cell genes and microRNAs associated with air pollution despite the low exposure levels, the short exposure periods and the relatively small-sized cohorts. Hsa-miR-197-3p, hsa-miR-29a-3p, hsa-miR-15a-5p, hsa-miR-16-5p and hsa-miR-92a-3p are found significantly expressed in association with exposures. These microRNAs target also relevant transcripts, indicating their potential relevance in the research of omics-biomarkers responding to air pollution. Furthermore, these microRNAs are also known to be associated with diseases previously linked to air pollution exposure including several cancers such lung cancer and Alzheimer's disease. In conclusion, we identified in this study promising compound-specific mRNA and microRNA biomarkers after two hours of exposure to low levels of air pollutants during two hours that suggest increased cancer risks.

Indoor, outdoor, and night work and blood concentrations of vitamin D and parathyroid hormone.

Objectives The aim of this study was to examine blood concentrations of 25-hydroxyvitamin D (25OHD) and parathyroid hormone (PTH) among indoor, outdoor, permanent and rotating night workers and the association with hours spent outdoors on and off work days. Methods Blood samples were collected from 425 workers (162 indoor, 112 outdoor, 118 rotating night and 33 permanent night workers) throughout all seasons. Serum concentrations of 25-hydroxyvitamin D (25OHD) and parathyroid hormone (PTH) were analyzed by isotope dilution liquid chromatography-tandem mass spectrometry (LC MS/MS) and an automated immune analyzer, respectively. Personal light exposure levels were continuously recorded and used to estimate hours spent outdoors (all workers). Results Permanent night workers had 25.3% (95% CI 11.9-36.6) lower 25OHD concentration, 4.55 (95% CI 1.39-14.94) higher odds of vitamin D insufficiency (<50 nmol/L) and 14.5% [95% confidence interval (CI) 0.1-31.1] higher PTH concentration than indoor workers. Outdoor workers had similar 25OHD concentrations but 7.5% (95% CI -0.5-14.9) lower PTH concentration compared to indoor workers. Rotating night workers 25OHD and PTH concentrations did not differ from indoor workers. Concentration of 25OHD increased by 5.2% (95% CI 1.1-9.5) per hour spent outdoor at workdays in the summer. Conclusion Clinicians should be aware that vitamin D insufficiency may be more prevalent among permanent night workers and human resources should consider the positive effect of allowing workers to spend time outdoor during work hours.

Dynamics of coarse and fine particle exposure in transport microenvironments

A significant fraction of daily personal exposure to air pollutants occurs during commuting in transport microenvironments (TMEs). We carried out systematic mobile monitoring on a pre-defined route to assess personal exposure levels of particulate matter (PM) in four TMEs (bus, car, cycle and walk). Measurements were made during morning peak (MP), afternoon off-peak (OP) and evening peak (EP) hours in a typical UK town, Guildford. The objectives were to quantify the real-time exposure to fine and coarse particles, identify the factors influencing their spatiotemporal variation and estimate the respiratory deposition doses (RDD). The mean PM10 concentrations were 90 ± 63, 23 ± 9, 14 ± 17 and 63 ± 76 μg m−3 for bus, car, cycle and walk modes, respectively. The average ratios of PM2.5/PM10 were 0.32, 0.90, 0.67 and 0.36 for bus, car, cycle and car journeys, respectively. The mean concentrations of coarse particles (PM2.5-10) followed the trend: bus > walk > cycle > car. In contrast, mean concentrations of submicron (PM1) and fine particles (PM2.5) were usually high in the car while lowest for cyclists. RDD depend on the physical activity, particle size distribution and thus deposited fraction are not always proportional to the ambient concentration. RDD for coarse particles were largest for the walk mode (56 ± 14 μg h−1), followed by buses (31 ± 2 μg h−1), cycle (12 ± 3 μg h−1) and cars (1.2 ± 0.3 μg h−1). The corresponding RDD of fine particles were comparable for both walk (5.5 ± 0.3 μg h−1) and cycle (5.1 ± 1.2 μg h−1), followed by bus (4.1 ± 0.7 μg h−1) and car (2.0 ± 0.2 μg h−1). Car mode experienced both the least concentrations and RDD for coarse particles. It also had the lowest RDD for fine particles despite high concentrations. Physical activity of car commuters is modest compared with walking and cycling, which makes the rank ordering of RDD different than those of exposure concentrations. Hence the management of commuting exposures should consider potential dose and not just exposure concentration for curtailing adverse health effects related to commuting. RDD for pedestrian and cycle modes were not the lowest among the measured modes but opportunities such as an increased distance between the heavily trafficked roadways and pedestrians/cyclists should be considered in urban planning to reduce potential doses.

Personal exposure of PM2.5 emitted from solid fuels combustion for household heating and cooking in rural Guanzhong Plain, northwestern China

Household solid fuel combustion for heating and cooking in rural areas is an important source of fine particulate matter (PM2.5) in northwestern China, which largely contributes to PM2.5 personal exposure concentrations during the cold winter. There is a general lack of understanding about the personal exposure to PM2.5 and to its chemical components emitted from domestic solid fuel combustion in northwestern Chinese rural populations. In this work, personal exposure to PM2.5 was sampled using a portative device together with fixed indoor and outdoor fixed samplings in Guanzhong Plain in December 2016 for the purpose of characterizing personal exposure to PM2.5 as a function of different solid fuels used in rural households. The average housewife's personal exposure to PM2.5 concentration was 263.4 ± 105.8 μg m−3 (1σ, n = 30), which was about 40% higher than the values found indoors (186.5 ± 79.5 μg m−3, 1σ, n = 30) and outdoors (191.0 ± 85.3 μg m−3, 1σ, n = 30). High personal exposure PM2.5 levels were mainly related to the ignition of solid fuels for heating and cooking. Correlations among personal exposure, indoor and outdoor PM2.5 levels and their mutual ratios were computed to investigate how personal exposure to fine aerosols can be related to microenvironmental PM2.5 levels and to individual activities. The results showed that households using electric power for heating and cooking were characterized by an average personal exposure PM2.5 value of 156.8 ± 36.6 μg m−3 (1σ, n = 6) while personal exposure to PM2.5 in households using solid fuels was twice higher (310.8 ± 90.4 μg m−3, 1σ, n = 24). Solid fuel combustion products and related secondary formed species dominated PM2.5 mass in personal exposure, indoor and outdoor samples. Motor vehicle emission and various dust sources were two other main contributors identified. Our results demonstrated that the use of clean energy could be an effective measure to reduce personal exposure levels of PM2.5 emitted from domestic solid fuels combustion in winter in rural areas, which implied that the government should speed up the upgrade of the heating and cooking equipment fleet to protect the health of rural residents in northwestern China.

Spatial and temporal variability of personal environmental exposure to radio frequency electromagnetic fields in children in Europe

BackgroundExposure to radiofrequency electromagnetic fields (RF-EMF) has rapidly increased and little is known about exposure levels in children. This study describes personal RF-EMF environmental exposure levels from handheld devices and fixed site transmitters in European children, the determinants of this, and the day-to-day and year-to-year repeatability of these exposure levels. MethodsPersonal environmental RF-EMF exposure (μW/m2, power flux density) was measured in 529 children (ages 8–18 years) in Denmark, the Netherlands, Slovenia, Switzerland, and Spain using personal portable exposure meters for a period of up to three days between 2014 and 2016, and repeated in a subsample of 28 children one year later. The meters captured 16 frequency bands every 4 s and incorporated a GPS. Activity diaries and questionnaires were used to collect children's location, use of handheld devices, and presence of indoor RF-EMF sources. Six general frequency bands were defined: total, digital enhanced cordless telecommunications (DECT), television and radio antennas (broadcast), mobile phones (uplink), mobile phone base stations (downlink), and Wireless Fidelity (WiFi). We used adjusted mixed effects models with region random effects to estimate associations of handheld device use habits and indoor RF-EMF sources with personal RF-EMF exposure. Day-to-day and year-to-year repeatability of personal RF-EMF exposure were calculated through intraclass correlations (ICC). ResultsMedian total personal RF-EMF exposure was 75.5 μW/m2. Downlink was the largest contributor to total exposure (median: 27.2 μW/m2) followed by broadcast (9.9 μW/m2). Exposure from uplink (4.7 μW/m2) was lower. WiFi and DECT contributed very little to exposure levels. Exposure was higher during day (94.2 μW/m2) than night (23.0 μW/m2), and slightly higher during weekends than weekdays, although varying across regions. Median exposures were highest while children were outside (157.0 μW/m2) or traveling (171.3 μW/m2), and much lower at home (33.0 μW/m2) or in school (35.1 μW/m2). Children living in urban environments had higher exposure than children in rural environments. Older children and users of mobile phones had higher uplink exposure but not total exposure, compared to younger children and those that did not use mobile phones. Day-to-day repeatability was moderate to high for most of the general frequency bands (ICCs between 0.43 and 0.85), as well as for total, broadcast, and downlink for the year-to-year repeatability (ICCs between 0.49 and 0.80) in a small subsample. ConclusionThe largest contributors to total personal environmental RF-EMF exposure were downlink and broadcast, and these exposures showed high repeatability. Urbanicity was the most important determinant of total exposure and mobile phone use was the most important determinant of uplink exposure. It is important to continue evaluating RF-EMF exposure in children as device use habits, exposure levels, and main contributing sources may change.

Bovine Allergens in a Ruminant Clinic and Dairy Barns: Exposure Levels, Determinants, and Variability.

Dairy farmers may develop specific sensitization and allergic airway diseases due to bovine allergens. However, dose-response relationships are lacking, and as yet little is known on bovine allergen exposure levels. To investigate bovine allergen exposure levels in a ruminant clinic and dairy barns, and to assess exposure determinants and variability of exposure. Samples were collected using active and passive airborne dust measurements in a ruminant clinic and several dairy barns. Bovine allergen levels were determined by sandwich enzyme-linked immunosorbent assay. Linear mixed models were applied to explore the association between bovine allergen exposure levels and potential exposure determinants. Day-to-day within-worker and between-worker exposure variability was determined, as well as how exposure determinants affect exposure variability. Bovine allergens were measureable in all samples. Personal bovine allergen exposure levels in the ruminant clinic ranged from 0.10 to 24.8 µg/m3, geometric mean (GM) 1.34 µg/m3. Exposure levels varied dependent on job titles. Personal exposure levels in dairy barns ranged from 0.10 to 46.8 µg/m3, GM 1.47 µg/m3. Type of bedding materials in the barns appeared to be a significant determinant of bovine allergen levels. Compost bedding, particularly, increased allergen levels. Milking by robot was the most important determinant explaining between-worker exposure variability, while bedding was important as well. Bovine allergen levels in stationary measurements were somewhat lower than personal measurements (GM ratio 0.47). Bovine allergens could be readily detected in electrostatic dust-fall collector measurements. This study provides insight in bovine allergen exposure levels and their determinants, which is a first step to investigate dose-response relationships between sensitization/allergy associated with exposure to bovine allergen levels in future studies.

Comparative analysis of personal exposure levels induced by long‐term evolution 1800 Re‐farming and other RF sources in an urban environment

Narrowband analysis of real-life up-link (UL) and down-link (DL) trends in personal exposure to recently installed long-term evolution 1800 and other radio frequency sources in typical everyday environments is presented in this work. Results are derived by analysis and post-processing of experimental dataset consisting of 1,677,600 measurement samples, taken at a sampling frequency of 0.25 Hz. The electric field measurements were collected with calibrated personal exposure meters at 90 urban spots, including outdoor and indoor microenvironments. A robust regression from order statistics was applied, enabling the determination of more reliable mean exposure values (V/m) for each wireless and broadcast technology and microenvironment. The exposure ratio for global system for mobile communications (GSM) + long-term evolution (LTE) 1800 (UL) and GSM + LTE 1800 (down link, DL) varied between 0.004 and 0.546% in outdoor environments. The maximal electric field value for the GSM + LTE 900 (DL) was 1.77 V/m, while for GSM + LTE 1800 (DL) this value was 0.644 V/m. The cumulative distribution function of the total radio frequency exposure for the various microenvironments is presented. The research results confirm that exposure levels in an urban environment even after the LTE 1800 Re-farming deployment are far below the International Commission on Non-ionising Radiation Protection reference levels.

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.

Design and application of a web-based real-time personal PM2.5 exposure monitoring system

Growing demand from public health research for conduct large-scale epidemiological studies to explore health effect of PM2.5 was well-documented. To address this need, we design a web-based real-time personal PM2.5 exposure monitoring system (RPPM2.5 system) which can help researcher to get big data of personal PM2.5 exposure with low-cost, low labor requirement, and low operating technical requirements. RPPM2.5 system can provide relative accurate real-time personal exposure data for individuals, researches, and decision maker. And this system has been used in a survey of PM2.5 personal exposure level conducted in 5 cities of China and has provided mass of valuable data for epidemiological research.

Noise exposure and hearing status among call center operators.

Introduction:The overall objective of the study was to assess noise exposure and audiometric hearing threshold levels (HTLs) in call center operators.Materials and Methods:Standard pure-tone audiometry and extended high-frequency audiometry were performed in 78 participants, aged 19 to 44 years (mean ± standard deviation: 28.1 ± 6.3 years), employed up to 12 years (2.7 ± 2.9 years) at one call center. All participants were also inquired about their communication headset usage habits, hearing-related symptoms, and risk factors for noise-induced hearing loss (NIHL). Noise exposure under headsets was evaluated using the microphone in a real ear technique as specified by ISO 11904-1:2002. The background noise prevailing in offices was also measured according to ISO 9612:2009.Results and Discussion:A personal daily noise exposure level calculated by combining headset and nonheadset work activities ranged from 68 to 79 dBA (74.7 ± 2.5 dBA). Majority (92.3%) of study participants had normal hearing in both ears (mean HTL in the frequency range of 0.25–8 kHz ≤20 dB HL). However, their HTLs in the frequency range of 0.25 to 8 kHz were worse than the expected median values for equivalent highly screened otologically normal population, whereas above 8 kHz were comparable (9–11.2 kHz) or better (12.5 kHz). High-frequency hearing loss (mean HTLs at 3, 4, and 6 kHz >20 dB HL) and speech-frequency hearing loss (mean HTLs at 0.5, 1, 2, and 4 kHz >20 dB HL) were noted in 8.3% and 6.4% of ears, respectively. High-frequency notches were found in 15.4% of analyzed audiograms. Moreover, some of call center operators reported hearing-related symptoms.Conclusions:Further studies are needed before firm conclusions concerning the risk of NIHL in this professional group can be drawn.

Representativeness and repeatability of microenvironmental personal and head exposures to radio-frequency electromagnetic fields

The aims of this study were to: i) investigate the repeatability and representativeness of personal radio frequency-electromagnetic fields (RF-EMFs) exposure measurements, across different microenvironments, ii) perform simultaneous evaluations of personal RF-EMF exposures for the whole body and the head, iii) validate the data obtained with a head-worn personal distributed exposimeter (PDE) against those obtained with an on-body worn personal exposimeter (PEM). Data on personal and head RF-EMF exposures were collected by performing measurements across 15 microenvironments in Melbourne, Australia. A body-worn PEM and a head-worn PDE were used for measuring body and head exposures, respectively. The summary statistics obtained for total RF-EMF exposure showed a high representativeness (r2 > 0.66 for two paths in the same area) and a high repeatability over time (r2 > 0.87 for repetitions of the same path). The median head exposure in the 900MHz downlink band ranged between 0.06V/m and 0.31V/m. The results obtained during simultaneous measurements using the two devices showed high correlations (0.42 < r2 < 0.94). The highest mean total RF-EMF exposure was measured in Melbourne's central business district (0.89V/m), whereas the lowest mean total exposure was measured in a suburban residential area (0.05V/m). This study shows that personal RF-EMF microenvironmental measurements in multiple microenvironments have high representativeness and repeatability over time. The personal RF-EMF exposure levels (i.e. body and head exposures) demonstrated moderate to high correlations.

High airborne black carbon concentrations measured near roadways in Nairobi, Kenya

Airborne black carbon (BC) particles have serious implications for human health and climate change and thus represent a prime target for mitigation policies. The sources of BC include vehicles burning diesel fuel, which are common in urban areas in low-income countries. The objective of this study was to examine the possible relationship between traffic and airborne BC concentrations near roadways in Nairobi, Kenya. We measured personal exposure levels of BC in Nairobi in a field campaign in summer 2009, and subsequently confirmed our ability to estimate BC quantitatively by conducting a co-location experiment in Nairobi in the fall of 2011. The central business district of Nairobi recorded 11-h average daytime BC concentrations in the range 20–42 µg m−3 while the main highways feeding into Nairobi recorded BC levels of 17–79 µg m−3. As far as we are aware, the data reported here include the highest multi-hour BC concentrations ever reported in Africa. Samples from gradient sampling showed rapid reduction of BC concentrations with distance away from traffic. The measured BC near the curbside of roadways was estimated to be in the range of 34–56% of PM2.5, implying traffic was a dominant source of PM2.5 emissions in Nairobi. The high concentrations of BC that we observed raises concern regarding potential health threats to workers, residents, and visitors, and highlights the need for policies to address traffic-related air pollution in Nairobi.

Laboratory experiments regarding the use of filtration and retained heat to reduce particulate matter emissions from biomass cooking

There are a number of methods to help reduce the exposure to household air pollution associated with using biomass fuel for daily cooking and heating in nearly 40% of global households. These most commonly include use of cleaner fuels and cookstoves, increasing ventilation, and use of a chimney. This paper investigates two less-commonly considered methods, 1) reducing exposure through filtration and capture of PM2.5 and 2) avoiding emissions using retained heat for cooking. If cookstoves are operated inside an enclosure from which smoke is pulled by a fan through an inexpensive HEPA-type filter before exiting to the outside, the personal exposure levels, room concentrations, and external pollution might be reduced. To test this method, an enclosure was built from which a box fan pulled the air and PM2.5 through a filter, and four different filters were tested. The rate of PM2.5 production (mg/min) exiting the filter was monitored with gravimetric measurement under an emissions hood during the high and low power phases of the Water Boiling Test 4.2.3 conducted on a biomass rocket stove with forced draft. The average of seven baseline emissions tests with no filter was 7.5mg/min of PM2.5. The average of seven tests using the highest quality furnace filter (3M 2200) was reduced to 1.5mg/min and the difference was significant at 95% confidence. The use of retained heat to simmer also reduced emissions of PM2.5 to zero by burning the boil-phase-made-charcoal while 5l of water were simmered for 35min.

A comparison of personal exposure to air pollutants in different travel modes on national highways in India

People often travel a long distance on highways to the nearest city for professional/business activities. However, relatively few publications on passenger exposure to pollutants on highways in India or elsewhere are available. The aim of this study was to examine the contribution of different travel modes to passengers' pollutant exposure for a long distance travel on a national highway in India. We measured PM2.5 and CO exposure levels of the passengers over 200km on a national highway using two portable air monitors, EVM-7 and EPAM-5000. Personal concentration exposures and per min-, per hour-, per trip- and round trip mass exposures for three travel modes were calculated for 9 trips. Association between pollutants and weather variables were evaluated using levels Spearman correlation. ANOVA was carried out to evaluate the influence of travel mode, the timing of trips, temperature and RH on personal exposures. On an average, PM2.5 personal concentration exposure levels were highest in the car (85.41±61.85μgm−3), followed by the bus (75.08±55.39μgm−3) and lowest in the car (ac) (54.43±34.09μgm−3). In contrast, CO personal exposure was highest in the car (ac) (1.81±1.3ppm). Travel mode explained the highest variability for CO (18.1%), CO2 (9.9%), PM2.5 (1.2%) exposures. In-city mass exposures were higher than trip averages; PM2.5:1.21–1.22, 1.13–1.19 and 1.03–1.28 times; CO: 1.20–1.57, 1.37–2.10 and 1.76–2.22 times for bus, car and car (ac) respectively. Traveling by car (ac) results in the lowest PM2.5 exposures, although it exposes the passenger to high CO level. Avoiding national highways passing through cities can reduce up to 25% PM2.5 and 50% CO mass exposures. This information can be useful for increasing environmental awareness among the passengers and for framing better pollution control strategies on highways.

The relationship between the concentration of tetrachlorethylene in exhaled air and personal exposure levels in the dry cleaning workers

The relationship between the concentration of tetrachlorethylene in exhaled air and personal exposure levels in the dry cleaning workers

The investigation of relationship between ambient concentrations and personal exposure levels of formaldehyde in the pathological departments at teaching hospitals in Hamada university of Medical Sciences

The investigation of relationship between ambient concentrations and personal exposure levels of formaldehyde in the pathological departments at teaching hospitals in Hamada university of Medical Sciences

Behavioral interventions to reduce nickel exposure in a nickel processing plant

ABSTRACTNickel is a widely-used material in many industries. Although there is enough evidence that occupational exposure to nickel may cause respiratory illnesses, allergies, and even cancer, it is not possible to stop the use of nickel in occupational settings. Nickel exposure, however, can be controlled and reduced significantly in workplaces.The main objective of this study was to assess if educational intervention of hygiene behavior could reduce nickel exposure among Indonesian nickel smelter workers. Participants were randomly assigned to three intervention groups (n = 99). Group one (n = 35) received only an educational booklet about nickel, related potential health effects and preventive measures, group two (n = 35) attended a presentation in addition to the booklet, and group three (n = 29) received personal feedback on their biomarker results in addition to the booklet and presentations. Pre- and post-intervention air sampling was conducted to measure concentrations of dust and nickel in air along with worker's blood and urine nickel concentrations. The study did not measure significant differences in particles and nickel concentrations in the air between pre- and post-interventions. However, we achieved significant reductions in the post intervention urine and blood nickel concentrations which can be attributed to changes in personal hygiene behavior. The median urinary nickel concentration in the pre-intervention period for group one was 52.3 µg/L, for group two 57.4 µg/L, and group three 43.2 µg/L which were significantly higher (p< = 0.010) than those measured in the post-intervention period for each of the groups with 8.5 µg/L, 9.6 µg/L, and 8.2 µg/L, respectively. A similar pattern was recorded for serum nickel with significantly (p < 0.05) higher median concentrations measured in the pre-intervention period for group one 1.7 µg/L, and 2.0 µg/L for group 2 and group 3 compared with the post intervention median serum nickel levels of 0.1 µg/L for all groups.The study showed that educational interventions can significantly reduce personal exposure levels to nickel among Indonesian nickel smelter workers.

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.

Personal Exposure to Ultrafine Particles According to Different Environments and Modes of Transport in Schoolchildren: Results from a Spanish Cohort in Valencia

Background Combustion, especially in diesel engines, emits a complex mixture of gases and particles that could be harmful for the respiratory and cardiovascular systems. Daily personal exposure to the smallest particulate matter (less than 0.1 µm and usually called nanoparticles or ultrafine particles – UFP) has been studied to a lesser extent compared to coarser particles. In this study we aim to assess personal exposure to UFP in different environments and transport modes among schoolchildren from a Spanish birth-cohort in the province of Valencia. Methods The study population consisted of 114 children aged 10-11 years. For each of them, personal exposure to UFP was measured continuously during two successive school days (24 hours) by means of a small backpack equipped with a UFP active sampler (DISCmini). The first day, a technician delivered the required material to the child’s home and instructed them on the monitoring period. The second day, families came to the health center where children underwent health examinations and parents answered questionnaires about time-activity patterns, sociodemographic factors, and other exposures. Median UFP exposure levels (numbers of particles per cm 3 – N/cm 3 – were obtained for the overall period, for different environments (at home and school) and during journeys by different modes of transport (active transport – walking or cycling – or passive transport – car, bus, metro or tram). Results Around 90% (N=101) of the schoolchildren had valid exposure data (at least at home and school). Mean monitoring time was 24 hours [range: 22-27 hours]. Participants spent 15 hours at home, 6 hours at school, 28 minutes in active transport, and 60 minutes in passive transport on average during the monitoring period. Passive transport in our study was over-represented since on the second day of the visit most families drove to the health center. Over this period, DISCmini obtained valid data for 98.5% of the time [interquartile range: 80.1%-100.0%]. Global personal exposure level was 9368 N/cm 3 [interquartile range: 5514-17607 N/cm 3 ], being higher during the cold season. Personal exposure levels were higher during journeys (especially in passive transport) than in other environments. Comparing exposure levels at home and school, UFP levels were higher at home, probably due to burning appliances (e.g., gas cooker). Conclusions Schoolchildren were exposed to a wide range of UFP levels. Personal exposure levels varied across the studied environments, being higher during journeys and especially in passive modes of transport.