Personal Exposure Measurements Research Articles

Validity of Mobility-Based Exposure Assessment of Air Pollution: A Comparative Analysis with Home-Based Exposure Assessment.

Air pollution exposure is typically assessed at the front door where people live in large-scale epidemiological studies, overlooking individuals' daily mobility out-of-home. However, there is limited evidence that incorporating mobility data into personal air pollution assessment improves exposure assessment compared to home-based assessments. This study aimed to compare the agreement between mobility-based and home-based assessments with personal exposure measurements. We measured repeatedly particulate matter (PM2.5) and black carbon (BC) using a sample of 41 older adults in the Netherlands. In total, 104 valid 24 h average personal measurements were collected. Home-based exposures were estimated by combining participants' home locations and temporal-adjusted air pollution maps. Mobility-based estimates of air pollution were computed based on smartphone-based tracking data, temporal-adjusted air pollution maps, indoor-outdoor penetration, and travel mode adjustment. Intraclass correlation coefficients (ICC) revealed that mobility-based estimates significantly improved agreement with personal measurements compared to home-based assessments. For PM2.5, agreement increased by 64% (ICC: 0.39-0.64), and for BC, it increased by 21% (ICC: 0.43-0.52). Our findings suggest that adjusting for indoor-outdoor pollutant ratios in mobility-based assessments can provide more valid estimates of air pollution than the commonly used home-based assessments, with no added value observed from travel mode adjustments.

31 A proposed database of task-based, area and personal noise exposure measurements suitable for risk assessment in non-mining Southern African workplaces

31 A proposed database of task-based, area and personal noise exposure measurements suitable for risk assessment in non-mining Southern African workplaces

Assessment of Occupational Exposure to Inhalable Aerosols in an Instant Powdered Food Manufacturing Plant in Norway

BackgroundIn the food manufacturing industry, exposure to inhalable aerosols contributes to respiratory illnesses such as occupational asthma and rhinitis. However, there is a lack of comprehensive exposure assessment studies. This study evaluated occupational exposure to inhalable aerosols in an instant powdered food manufacturing plant during work operations involving dried food and powders. MethodsIn total, 50 workers from an instant powdered food manufacturing plant were recruited. Personal inhalable aerosol exposure measurements were taken for both full-shift and task-based activities. The concentrations of inhalable aerosols were analyzed to identify any variation within and across departments, as well as between seasons, handedness, and sex. ResultsIn total, 134 personal air samples were collected, and the particulate mass was determined gravimetrically. The concentrations of inhalable aerosols ranged from 0.1 to 27 mg/m3 for full-shift exposure measurements and 3.1 to 73 mg/m3 for task-based measurements. Statistically significant differences in mean aerosol concentrations were found across departments (A:B p < 0.001, A:C p < 0.05, B:C p < 0.001) and between seasons (p < 0.001). ConclusionThis study revealed high exposure to inhalable aerosols among workers, particularly those involved in manual weighing, mixing, and adding powders. The significant differences between departments highlight the specific activities contributing to increased inhalable aerosol concentrations. Seasonal variations were also evident, with autumn showing higher concentrations of inhalable aerosols in all departments compared with summer. These findings emphasize the importance of understanding the distribution of aerosol concentrations across different work tasks and departments, particularly during different seasons.

Radiation exposure in therapeutic endoscopic retrograde cholangiopancreatography with two types of fluoroscopy systems

AbstractFluoroscopy is necessary for endoscopic retrograde cholangiopancreatography (ERCP). Occupational radiation exposure of staff (endoscopists, nurses, or assistants) is inevitable. Fluoroscopes with a tube over‐couch (OC) rather than under‐couch (UC) may have more radiation reflection dosage on the staff's upper body theoretically, where the most vital organs are. In the study, we assessed the radiation exposure on staff by two different types of fluoroscopes in real‐world practice. Using a radiation dosimeter to measure the radiation dosage on endoscopists and assistants in each ERCP procedure under two different fluoroscopic systems (UC vs. OC). Forty‐one ERCP procedures were enrolled. Dosimeters were used NanoDots for the measurement of personal radiation exposure. Those dosimeters were attached to the left forearm and chest of the endoscopist and only the chest of two assistants, the wall of the ERCP room, and the controlling room in every procedure. Nine‐teen ERCPs were performed under the OC unit, and the other 22 ERCPs were UC method. Fluoroscopic time and output of radiation dose showed no significant difference between the two groups. Radiation exposure in endoscopist were 0.0911[0.1041–0.3974] mGy (OC) versus 0.0276 [0.0080–0.2924] mGy (UC), p &lt; .01 for the forearm; and 0.0318 [0.0070–0.2628] mGy (OC) versus 0.0182 [0.0088–0.1628] mGy (UC), p = .04 for the endoscopist's body. There was no difference in radiation exposure from assistants in both groups. For all the ERCP procedures, the measurement of radiation exposure from high to low is endoscopist's hand, endoscopist's body, assistant 1, assistant 2, and ERCP room (p &lt; .01). Radiation detection from ERCP room is slightly higher but close to controlling room (p = .06). For the safety of occupational radiation protection, tube of fluoroscope UC is better than OC for the endoscopists more than assistants. Besides, the assistant 1 took higher radiation exposure than assistant 2 for each ERCP procedure.

Elastic TTC–PVA gel dosimeters for personal UV exposure measurements

This work presents a new personal chemical gel dosimeter containing a radiation-sensitive 2,3,5-triphenyltetrazolium chloride embedded in a poly(vinyl alcohol) matrix for UV radiation measurements. The dosimeter changes colour from colourless to pink under the influence of UV radiation, and colour intensity increases with increasing absorbed dose. The dosimeter was characterised using reflectance spectrophotometry for stability, repeatability, and dose–response, including dose sensitivity, threshold dose, as well as linear and dynamic dose range. The TTC–PVA dosimeter can be used to measure UVA, UVB, and UVC radiation, as well as actual solar radiation consisting of UVA and UVB radiation. As a result, it is promising for use as a personal dosimeter for people exposed to UV radiation from artificial and natural sources. The comfort of using the dosimeter would be ensured by its flexibility, which allows it to be properly adjusted to the curvatures of the human body.

Exposure risk to rural Residents: Insights into particulate and gas phase pesticides in the Indoor-Outdoor nexus

Rural residents are exposed to both particulate and gaseous pesticides in the indoor-outdoor nexus in their daily routine. However, previous personal exposure assessment mostly focuses on single aspects of the exposure, such as indoor or gaseous exposure, leading to severe cognition bias to evaluate the exposure risks. In this study, residential dust and silicone wristbands (including stationary and personal wearing ones) were used to screen pesticides in different phases and unfold the hidden characteristics of personal exposure via indoor-outdoor nexus in intensive agricultural area. Mento-Carlo Simulation was performed to assess the probabilistic exposure risk by transforming adsorbed pesticides from wristbands into air concentration, which explores a new approach to integrate particulate (dust) and gaseous (silicone wristbands) pesticide exposures in indoor and outdoor environment. The results showed that particulate pesticides were more concentrated in indoor, whereas significantly higher concentrations were detected in stationary outdoor wristbands (p < 0.05). Carbendazim and chlorpyrifos were the most frequently detected pesticides in dust and stationary wristbands. Higher pesticide concentration was found in personal wristbands worn by farmers, with the maximum value of 2048 ng g−1 for difenoconazole. Based on the probabilistic risk assessment, around 7.1 % of farmers and 2.6 % of bystanders in local populations were potentially suffering from chronic health issues. One third of pesticide exposures originated mainly from occupational sources while the rest derived from remoting dissipation. Unexpectedly, 43 % of bystanders suffered the same levels of exposure as farmers under the co-existence of occupational and non-occupational exposures. Differed compositions of pesticides were found between environmental samples and personal pesticide exposure patterns, highlighting the need for holistic personal exposure measurements.

Heat Exposure among Adult Women in Rural Tamil Nadu, India.

Exposure to heat is associated with a substantial burden of disease and is an emerging issue in the context of climate change. Heat is of particular concern in India, which is one of the world's hottest countries and also most populous, where relatively little is known about personal heat exposure, particularly in rural areas. Here, we leverage data collected as part of a randomized controlled trial to describe personal temperature exposures of adult women (40-79 years of age) in rural Tamil Nadu. We also characterize measurement error in heat exposure assessment by comparing personal exposure measurements to the nearest ambient monitoring stations and to commonly used modeled temperature data products. We find that temperatures differ across individuals in the same area on the same day, sometimes by more than 5 °C within the same hour, and that some individuals experience sharp increases in heat exposure in the early morning or evening, potentially a result of cooking with solid fuels. We find somewhat stronger correlations between the personal exposure measurements and the modeled products than with ambient monitors. We did not find evidence of systematic biases, which indicates that adjusting for discrepancies between different exposure measurement methods is not straightforward.

Club cell protein (CC16) in serum as an effect marker for small airway epithelial damage caused by diesel exhaust and blasting fumes in potash mining

ObjectiveThe effect marker club cell protein (CC16) is secreted by the epithelium of the small respiratory tract into its lumen and passes into the blood. Increased amounts of CC16 in serum are observed during acute epithelial lung injury due to air pollutants. CC16 in serum was determined as part of this cross-sectional study in underground potash miners on acute and chronic health effects from exposures to diesel exhaust and blasting fumes.MethodsNitrogen oxides, carbon monoxide, and diesel particulate matter were measured in 672 workers at a German potash mining site on a person-by-person basis over an early shift or midday shift, together with CC16 serum concentrations before and after the respective shift. CC16 concentrations and CC16 shift-differences were evaluated with respect to personal exposure measurements and other quantitative variables by Spearman rank correlation coefficients. CC16 shift-differences were modeled using multiple linear regression. Above-ground workers as reference group were compared to the exposed underground workers.ResultsSerum concentrations of CC16 were influenced by personal characteristics such as age, smoking status, and renal function. Moreover, they showed a circadian rhythm. While no statistically significant effects of work-related exposure on CC16 concentrations were seen in never smokers, such effects were evident in current smokers.ConclusionThe small airways of current smokers appeared to be vulnerable to the combination of measured work-related exposures and individual exposure to smoking. Therefore, as health protection of smokers exposed to diesel exhaust and blasting fumes, smoking cessation is strongly recommended.

Increased Risk for Hospitalization Associated with Short Term Particle Air Pollution Exposure for California Residents with Sickle Cell Disease

Background: Air pollution is associated with numerous adverse health outcomes in the general population such as asthma exacerbations, pneumonia, myocardial infarction, and stroke. There is a strong association between air pollution and mechanistic processes associated with oxidative stress, vasoconstriction, and inflammation, suggesting a high risk of exposure for those with sickle cell disease (SCD). A small number of published studies have explored this relationship, primarily focusing on children. Only two studies have examined air pollution in the US, both with outcomes among urban area hospitals in Atlanta, GA. None have taken place in California, which has the worst air quality, including the four most polluted cities in year-round particle pollution in the nation. Additionally, all published studies have overlooked more rural exposure areas. Recent advances in environmental exposure assessment have enabled high-resolution predictions of ambient air pollution concentrations in the whole US, making it possible to cover unmonitored suburban and rural areas that were unrepresented in the past. In addition, these high-resolution predictions are more precise surrogates of the personal exposure measures than monitored data. Particulate matter with a diameter of 2.5 microns or less (PM 2.5) is the most harmful pollutant based on current research findings. We hypothesized that short term increases in PM 2.5 exposure were associated with an increased risk for hospitalization among individuals with SCD in California. Methods: We designed a time-stratified case-crossover study to estimate the percent change in risk for hospitalization for SCD complications associated with each 1mg/m 3 increase in PM 2.5 exposure. The zip code of residence was used to spatially link each hospital admission with PM 2.5 exposure using a novel hybrid exposure model allowing for estimated exposure in areas without direct remote sensing. We used conditional logistic regressions to examine the PM 2.5 exposures at 7-day moving average and single lag days (from lag 0 to 6 days) before admission, adjusting for nonlinear confounding effects of air temperature and humidity at the same exposure window. We examined risk for all hospitalizations and specifically for vaso-occlusive pain (VOC) and acute chest syndrome (ACS). Results: From 2000-2016, among 5,835 California residents with SCD, there were 107,450 admissions for sickle cell disease complications with VOC being the most common indication (71.1%). PM 2.5 air pollution data was examined among 2,634 zip codes throughout the state. Residents with SCD were noted to be living among 1,180 zip codes. The daily burden of PM 2.5 was higher in zip codes with residents with SCD (mean 11.5 mg/m 3, standard deviation [SD] 9.0) when compared to zip codes without residents known to have SCD (mean 9.2 mg/m 3, SD 8.6, p&amp;lt;0.001) ( Table 1). Overall, the mean daily burden of PM 2.5 declined in the period of 2010-2016 when compared to that from 2000-2009. However, the daily mean PM 2.5 concentration remained higher in zip codes with individuals with SCD. No significant association was seen in examining the week-long exposure to PM 2.5 and increase risk in hospitalizations for any indication over the entire study period (2000-2016). However, when examining the more contemporary period of 2010-2016, we identified that each 1mg/m 3 increase in PM 2.5 was associated with 0.22% increased risk for SCD hospitalization (Confidence Interval [CI] 0.02-0.42, p=0.03) 3 days prior to admission. We observed a 0.26% increased risk for hospitalization for VOC with each 1 mg/m 3 increase in PM 2.5 exposure (CI 0.02-0.49, p=0.03) at lag day 3 (Figure 1). No effect was seen with PM 2.5 on hospitalizations for ACS during any time period. Discussion: Our study suggests that short term air pollution exposure may be a trigger for hospitalization for individuals with SCD. In particular this effect is seen in the more recent years with a lower daily average PM 2.5 burden overall, suggesting attention may be needed well below Environmental Protection Agency (EPA) thresholds. Consistent with previous studies, lag day 3 PM 2.5 exposure is associated with an increased risk for hospitalization for VOC. These results may have important implications in understanding risk factors for hospitalization for children and adults with SCD.

Accurate low-dose exposure assessment of benzene and monoaromatic compounds by diffusive sampling: sampling and analytical method validation according to ISO 23320 for radiello® samplers packed with activated charcoal.

The research study aimed at providing an accurate low-dose benzene exposure assessment method, by validating diffusive monitoring techniques for benzene personal exposure measurements at workplaces where benzene concentrations are expected in the low ppb range, such as in the present-day chemical, petrochemical, foundry, and pharmaceutical industry. The project was aimed at addressing the need for a robust and fully validated method to perform personal exposure measurements considering that the occupational exposure limit value for benzene is going to be significantly lowered in the next few years. Diffusive sampling offers a reliable alternative to pumped sampling methods, intrinsic safety in potentially explosive atmospheres, lightness, and ease of use. In this study, the radiello® diffusive sampler, with the packed activated charcoal RAD130 adsorbing substrate [suitable for solvent desorption and analysis by high-resolution gas chromatography-flame ionization detection (HRGC-FID)], was used. The experiments have been conducted following the ISO 23320 standard in the range from 0.005 to 0.1 ppm (16 to 320 μg/m3), yielding a full validation of the sampling and analytical method. The sampler performances have fulfilled all requisites of the ISO 23320 standard, in particular: bias due to the selection of a non-ideal sorbent is lower than 10% (no significant back diffusion of benzene due to concentration change in the atmosphere); bias due to storage of samples for up to 2 months is lower than 10%; nominal uptake rate for benzene on RAD130 is 74.65 mL/min; and expanded uncertainty of the sampling and analytical method is 20.6%. The sampling and analytical method is therefore fit-for-purpose for the personal exposure measurements aimed at testing compliance with occupational exposure limit values for benzene. The method is also fit for short-duration exposure monitoring related to specific tasks, and other volatile organic compounds, usually found in the same workplaces, such as aliphatic and aromatic hydrocarbons and some oxygenated compounds, have also been studied. In particular, n-hexane and isopropyl benzene, whose classification is currently under revision, can be efficiently monitored by this technique.

Long-term monitoring of indoor, outdoor, and personal exposure to gaseous chemical compounds

Seasonal variations of chemical compounds in indoor air and outdoor air and personal exposure to these chemicals were continuously monitored for 6 years using four types of passive sampling devices: PSD-BPE/DNPH packed with 2,4-dinitrophenylhydrazine and trans-1,2-bis(2-pyridyl)ethylene coated silica for ozone and carbonyls; PSD-VOC packed with Carboxen 572 or Active Carbon Beads particles for volatile organic compounds; PSD-TEA packed with triethanolamine impregnated silica for acid gases; and PSD-TEA packed with phosphoric acid impregnated silica for basic gases. Many chemical compounds except for nitrogen dioxide, formic acid, and benzene showed seasonal variations with high concentrations in summer and low concentrations in winter. In particular, formaldehyde, nonanal, 2-ethyl-1-hexanol, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, and ammonia concentrations showed remarkable seasonal variation. For example, the concentration of formaldehyde in February and August was 5.9 and 40 μg/m3, respectively, a difference of about 7 times. Although there were large differences in the concentrations in each house, the fluctuation pattern was almost the same every year in each house. By contrast, nitrogen dioxide, formic acid, and benzene concentrations were low in summer and high in winter. These compounds were generated by kerosine and gas stoves in winter. Long-term continuous monitoring revealed that annual mean concentrations could be estimated using data from February and August. Personal exposure concentrations could be classified into four patterns: chemicals affected by the indoor environment such as formaldehyde, chemicals affected by the outdoor environment such as ozone, chemicals affected by the occupational environment such as hexane, and background level chemicals such as benzene (without kerosine and gas stoves). Indoor and outdoor measurements are means to investigate the “health” of each environment. Personal exposure measurement using PSD-samplers is suitable for assessing the health risk of chemical compounds to humans.

Job Exposure Matrix, a Solution for Retrospective Assessment of Particle Exposure in a Subway Network and Their Long-Term Effects.

Health effects after long-term exposure to subway particulate matter (PM) remain unknown due to the lack of individual PM exposure data. This study aimed to apply the job exposure matrix (JEM) approach to retrospectively assess occupational exposure to PM in the Parisian subway. Job, the line and sector of the transport network, as well as calendar period were four JEM dimensions. For each combination of these dimensions, we generated statistical models to estimate the annual average PM10 concentration using data from an exhaustive inventory of the PM measurement campaigns conducted between 2004 and 2020 in the Parisian subway and historical data from the Parisian air pollution monitoring network. The resulting JEM and its exposure estimates were critically examined by experts using the uncertainty analysis framework. The resulting JEM allows for the assignment of the estimated annual PM10 concentration to three types of professionals working in the subway: locomotive operators, station agents, and security guards. The estimates' precision and validity depend on the amount and quality of PM10 measurement data used in the job-, line-, and sector-specific models. Models using large amounts of personal exposure measurement data produced rather robust exposure estimates compared to models with lacunary data (i.e., in security guards). The analysis of uncertainty around the exposure estimates allows for the identification of the sources of uncertainty and parameters to be addressed in the future in order to refine and/or improve the JEM. The JEM approach seems relevant for the retrospective exposure assessment of subway workers. When applied to available data on PM10, it allows for the estimation of this exposure in locomotive operators and station agents with an acceptable validity. Conversely, for security guards, the current estimates have insufficient validity to recommend their use in an epidemiological study. Therefore, the current JEM should be considered as a valid prototype, which shall be further improved using more robust measurements for some jobs. This JEM can also be further refined by considering additional exposure determinants.

Personal exposure from free Wi-Fi hotspots in downtown Mexico City.

In 2019, the Government of Mexico City implemented actions that allowed citizens to approach a free Wi-Fi hotspot, where more than 13000 points have been installed throughout the city. In this work, we present the results of the measurements of personal exposure to Radiofrequency Electromagnetic Fields carried out in Plaza de la Constitución, better known as Zócalo located in the center of Mexico City. The measurements were taken by one of the researchers while walking on a weekday morning and afternoon, in different microenvironments (on the street, on public transport: subway, at the Zócalo, and finally, at home). We also carry out spot measurements in the center of the Zócalo. Subsequently, we carried out a comparative analysis of the different microenvironments, through box plot and violin plot, and we elaborate georeferenced and interpolated maps with intensity levels through the Kriging method, using the Geographic Information System. The Kriging interpolation gives us a good visualization of the spatial distribution of RF-EMF exposure in the study area, showing the highest and lowest intensity levels. The mean values recorded at the measured points in the Zócalo were 326 μW/m2 in the 2.4- to 2.5-GHz Wi-Fi band and 2370 μW/m2 in the 5.15- to 5.85-GHz Wi-Fi band. In the case of the mean values recorded on the street, they were 119 μW/m2 in the 2.4- to 2.5-GHz frequency band and 31.8 μW/m2 in the 5.15- to 5.85-GHz frequency band, like the values recorded at home, 122 μW/m2 and 33.9 μW/m2, respectively. All values are well below the reference levels established by the International Commission on Non-Ionizing Radiation Protection.

Effects of Interventions to Prevent Work-Related Asthma, Allergy, and Other Hypersensitivity Reactions in Norwegian Salmon Industry Workers (SHInE): Protocol for a Pragmatic Allocated Intervention Trial and Related Substudies.

Workers in the salmon processing industry have an increased risk of developing respiratory diseases and other hypersensitivity responses due to occupational exposure to bioaerosols containing fish proteins and microorganisms, and related allergens. Little is known about effective measures to reduce bioaerosol exposure and about the extent of skin complaints among workers. In addition, while identification of risk factors is a core activity in disease prevention strategies, there is increasing interest in health-promoting factors, which is an understudied area in the salmon processing industry. The overall aim of this ongoing study is to generate knowledge that can be used in tailored prevention of development or chronification of respiratory diseases, skin reactions, protein contact dermatitis, and allergy among salmon processing workers. The main objective is to identify effective methods to reduce bioaerosol exposure. Further objectives are to identify and characterize clinically relevant exposure agents, identify determinants of exposure, measure prevalence of work-related symptoms and disease, and identify health-promoting factors of the psychosocial work environment. Data are collected during field studies in 9 salmon processing plants along the Norwegian coastline. Data collection comprises exposure measurements, health examinations, and questionnaires. A wide range of laboratory analyses will be used for further analysis and characterization of exposure agents. Suitable statistical analysis will be applied to the various outcomes of this comprehensive study. Data collection started in September 2021 and was anticipated to be completed by March 2023, but was delayed due to the COVID-19 pandemic. Baseline data from all 9 plants included 673 participants for the health examinations and a total of 869 personal exposure measurements. A total of 740 workers answered the study's main questionnaire on demographics, job characteristics, lifestyle, health, and health-promoting factors. Follow-up data collection is not completed yet. This study will contribute to filling knowledge gaps concerning salmon workers' work environment. This includes effective workplace measures for bioaerosol exposure reduction, increased knowledge on hypersensitivity, allergy, respiratory and dermal health, as well as health-promoting workplace factors. Together this will give a basis for improving the work environment, preventing occupational health-related diseases, and developing occupational exposure limits, which in turn will benefit employees, employers, occupational health services, researchers, clinicians, decision makers, and other stakeholders. ClinicalTrials.gov NCT05039229; https://www.clinicaltrials.gov/study/NCT05039229. DERR1-10.2196/48790.

Understanding the time-activity pattern to improve the measurement of personal exposure: An exploratory and experimental research

Although ambient fine particulate matter (PM2.5) concentrations and their components are commonly used as proxies for personal exposure monitoring, developing an accurate and cost-effective method to use these proxies for personal exposure measurement continues to pose a significant challenge. Herein, we propose a scenario-based exposure model to precisely estimate personal exposure level of heavy metal(loid)s (HMs) using scenario HMs concentrations and time-activity patterns. Personal exposure levels and ambient pollution levels for PM2.5 and HMs differed significantly with corresponding personal/ambient ratios of approximately 2, and exposure scenarios could narrow the assessment error gap by 26.1–45.4%. Using a scenario-based exposure model, we assessed the associated health risks of a large sample population and identified that the carcinogenic risk of As exceeded 1 × 10−6, while we observed non-carcinogenic risks from As, Cd, Ni, and Mn in personal exposure to PM2.5. We conclude that the scenario-based exposure model is a preferential alternative for monitoring personal exposure compared to ambient concentrations. This method ensures the feasibility of personal exposure monitoring and health risk assessments in large-scale studies.

Noise Exposure and Hearing Loss among Workers at a Hammer Forge Company.

The National Institute for Occupational Safety and Health (NIOSH) evaluated continuous and impact noise exposures and hearing loss among workers at a hammer forge company. Full-shift personal noise exposure measurements were collected on forge workers across 15 different job titles; impact noise characteristics and one-third octave band noise levels were assessed at the forge hammers; and 4,750 historic audiometric test records for 483 workers were evaluated for hearing loss trends. Nearly all workers' noise exposures exceeded regulatory and/or recommended exposure limits. Workers working in jobs at or near the hammers had full-shift time-weighted average noise exposures above 100 decibels, A-weighted. Impact noise at the hammers reached up to 148 decibels. Analysis of audiometric test records showed that 82% of workers had experienced a significant threshold shift, as defined by NIOSH, and 63% had experienced a standard threshold shift, as defined by the Occupational Safety and Health Administration (OSHA). All workers with an OSHA standard threshold shift had a preceding NIOSH significant threshold shift which occurred, on average, about 7 years prior. This evaluation highlights forge workers' exposures to high levels of noise, including impact noise, and how their hearing worsened with age and length of employment.

Assessment of children's personal and land use regression model-estimated exposure to NO2 in Springfield, Massachusetts

Ambient nitrogen dioxide (NO2) is derived from tailpipe vehicle emission and is linked with various of health outcomes. Personal exposure monitoring is crucial for accurate assessment of the associated disease risks. This study aimed to evaluate the utility of a wearable air pollutant sampler in determining the personal NO2 exposure of school children for comparison with a model-based personal exposure assessment. We employed cost-effective, wearable passive samplers to directly measure personal exposure of 25 children (aged 12–13 years) in Springfield, MA to NO2 over a five-day period in winter 2018. NO2 levels were additionally measured at 40 outdoor sites in the same region using stationary passive samplers. A land use regression (LUR) model was developed based on the ambient NO2 measures, with a good prediction performance (R2 = 0.72) using road lengths, distance to highway, and institutional land area as predictor variables. Time-weighted averages (TWA), which incorporated the time-activity patterns of participants and LUR-derived estimates in children's primary microenvironments (homes, the school and commute paths), were calculated as an indirect measure of personal NO2 exposure. Results indicated that the conventional residence-based exposure estimate approach, often used in epidemiological studies, differed from the direct personal exposure and could overestimate the personal exposure by up to 109 %. TWA improved personal NO2 exposure estimates by accounting for the time activity patterns of individuals, a difference of 5.4 % ± 34.2 % was found for exposures compared to wristband measurements. Nevertheless, the personal wristband measurements exhibited a large variability due to the potential contributions from indoor and in-vehicle NO2 sources. The findings suggest that exposure to NO2 can be highly personalized based on individual activities and contact with pollutants in specific microenvironments, reaffirming the importance of measuring personal exposure.

90 Graphene – Exposure and Emissions at Two Pilot Plants

Abstract Graphene is a nanomaterial suitable for a wide variety of applications. The industrial production and use of graphene is, hence, increasing rapidly. The main challenge in assessing graphene exposure is that graphene is a carbon structure, making it comparable to look for a needle in a haystack. We have explored the possibility to analyze elemental carbon and black carbon as a measure of personal graphene exposure. Exposure and emission measurements for graphene were conducted at two pilot plants using on- and off-line techniques. One plant produces graphene, up to 10 tons per year, using liquid exfoliation technique. The other plant uses graphene to coat paper in a conventional roll-to-roll process. The measurements were conducted both stationary (in the emission zone and in the background) and as personal measurements (in the breathing zone of the workers). We have analyzed elemental carbon and black carbon as a measure of the personal exposure. In the emission and background zone we have measured number of particles and lung deposited surface area concentration of particles &amp;lt;300nm, mass concentration, and we have collected samples for electron microscopy analysis. The exposure was in general low, but we identified tasks with an increase emissions. Measurements of elemental carbon is a promising technique for occupational hygienists to find possible exposure to graphene.

126 Emission and Exposure Characterization During Metal Waste Recycling

Abstract Waste of electrical and electronic equipment (WEEE) is one of the fastest-growing waste streams in the EU. The airborne occupational and environmental exposures generated by this waste handling are poorly quantified, and the growing use of nanomaterials in electronics adds to the uncertainty of risk assessment. Emission and personal exposure measurements were carried out during industrial recycling for three different metal waste flows: WEEE, metal scrap and cables. Size distributions and number-, mass- and lung deposited surface area concentrations were assessed by on-line techniques, and filter samples were collected for gravimetric analyses, metal content, and electron microscopy. Samples for elemental analyses with Particle Induced X-ray Emission (PIXE) was collected by a 12-stage low-pressure impactor . Additionally, low-cost sensors were deployed for long term monitoring. By number, the size distributions from all three flows were heavily dominated by particles &amp;lt;100 nm. Electron microscopy showed that there are many different elements in the same particle and that the composition of different particles vary considerably. Abundant elements, according to ICP-MS, were Fe, Al, Zn, and Cu, but Pb, Mn, Ba, and Co were also detected. PIXE analysis showed that the chemical composition indeed is different in different particle sizes, with e.g. Cr almost exclusively being present in particles &amp;lt; 200 nm. Low-cost sensors, not previously used for monitoring in highly polluted industrial settings, functioned well after 30 days. This study shows that detailed particle characterization is crucial for understanding of today’s and tomorrow’s waste recycling exposures, and as input to future toxicological assessments.

55 Validation of Diffusive Sampling Methods for Accurate Low-Dose Benzene Exposure Assessment, Inhalation Monitoring

Abstract The present research project is aimed at providing an accurate low-dose benzene exposure assessment method, by validating diffusive monitoring techniques for benzene personal exposure measurements at workplaces where low benzene concentrations are expected. The experiments have been conducted following the EN 838:2010 standard in the range of 16 to 320 µg/m3 (0.005 to 0.1 ppm). The study is part of the Concawe project on “accurate low-dose benzene exposure assessment, dose-specific metabolism and potential early markers” aiming at developing a methodology to monitor benzene exposures at low levels in environments typical of the petroleum industry. Diffusive sampling offers a reliable alternative to pumped sampling methods, intrinsic safety in potentially explosive atmospheres, lightness and ease of use. The tested diffusive sampler is radiello™, two alternative configurations of the sampler can be used: RAD130, packed with activated charcoal, suitable for solvent desorption and analysis by HRGC-FID, and RAD145, packed with graphitised charcoal, suitable for thermal desorption and analysis by HRGC-MS. For both configurations the sampler performances have fulfilled all requisites of the EN 838:2010 standard, in particular: bias due to the selection of a non-ideal sorbent is lower than 10% (no significant back diffusion of benzene due to concentration change in the atmosphere); bias due to storage of samples for up to 2 months is lower than 10%; nominal uptake rate for benzene on RAD130 is 74.6 ml/min and on RAD145 is 32.3 ml/min; expanded uncertainty of the sampling and analytical method is 20.2% on RAD130 and 26.1% on RAD145.