Thoracic Aerosol Research Articles

Content of clinker and other materials in personal thoracic aerosol samples from cement plants estimated by scanning electron microscopy and energy-dispersive X-ray microanalysis.

To estimate the composition and exposure to clinker and other specific components in personal thoracic dust samples of cement production workers. A procedure for the classification of airborne particles in cement production plants was developed based on classification trees. For this purpose, the chemical compositions of 27,217 particles in 29 material samples (clinker, limestone, gypsum, clay, quartz, bauxite, iron source, coal fly ash, and coal) were determined automatically by scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDX). The concentrations of the major elements in cement (calcium, aluminium, silicon, iron, and sulphur) were used for the classifications. The split criteria of the classification trees obtained in the material samples were used to classify 44,176 particles in 34 personal thoracic aerosol samples. The contents of clinker and other materials were estimated, and the clinker contents were analysed statistically for differences between job types and job tasks. Between 64% and 88% of the particles from material samples were classified as actual materials. The material types with variable composition (clay, coal fly ash, and coal) were classified with the lowest consistency (64% to 67%), while materials with a more limited compositional variation (clinker, gypsum, and quartz) were classified more consistently (76% to 85%). The arithmetic mean (AM) of the clinker content in personal samples was 62.1%, the median was 55.3%, and 95% confidence interval (CI) was 42.6% to 68.1%. No significant differences were observed between job types. However, the clinker content in samples when workers handled materials with high clinker content was significantly higher than when materials with lower clinker content were handled, 85% versus 65% (P = 0.02). The limestone content was AM 14.8%, median 13.2% (95% CI 5.5 to 20.9), whereas the other materials were present with relative abundances of median ≤ 6.4%. Automated particle analysis by SEM-EDX followed by classification tree analysis quantified clinker with fairly high consistency when evaluated together with raw materials that are expected to be airborne in cement production plants. The clinker proportions for job types were similar. Tasks a priori ranked by assumed clinker content were significantly different and according to expectations, which supports the validity of the chosen methodology. The composition of personal samples of mineral aerosols in the cement production industry could be estimated by automated single particle analysis with SEM-EDX and classification by a classification tree procedure. Clinker was the major component in the thoracic aerosol that cement production workers were exposed to. Differences between job types were relatively small and not significant. The clinker content from tasks was in agreement with assumptions.

Exposure to Particulate Matter and Respirable Crystalline Silica in Tunnel Construction Workers Using Tunnel Boring Machines.

This study aimed to assess the exposure to a selection of aerosols and gases in the work environment for workers performing tunnel construction using tunnel boring machines (TBMs), to identify determinants of exposure based on the information available and to calculate robust estimates of exposure using a statistical model. The focus was particulate matter (PM) and respirable crystalline silica (RCS). In addition, concentrations of nitrogen dioxide (NO2), elemental carbon (EC), and oil mist were assessed. Personal sampling was conducted from February 2017 to February 2019. PM in the thoracic and the respirable aerosol fractions was collected, and RCS was determined in the respirable aerosol fraction. Context information was collected on questionnaires. Because the workers could participate in the sampling more than once and multiple measurements were performed on the same date a mixed model was used in the analysis. Concentrations of PM and RCS are presented as estimated and measured geometric means (GMest and GMmea) and estimated arithmetic mean (AMest) in addition to the median. Measured concentrations of NO2, EC, and oil mist are presented as geometric means. A total of 290 and 289 personal samples of PM in the thoracic and respirable aerosol fractions were available for analysis, respectively. Work title/work location, type of work (production, maintenance, or a combination of the two), and date of sampling were identified as determinants of exposure. Workers in the front of the TBMs had the highest exposure to PM and RCS. The GMest of RCS exposure varied from 35 to 413 μg m-3 depending on the work title. The geometric standard deviations for measured RCS concentrations by work title ranged from 1.6 to 3.5. A total of 16 samples of NO2 and EC and 12 samples of oil mist were collected. Maximum values of NO2 and EC were 54 µg m-3 and 23 µg m-3, respectively. The maximum measured value of oil mist was 0.08 mg m-3. All TBM workers were exposed to PM and RCS. Exposure to RCS may be substantial, and workers in front of the TBM were exposed to the highest concentrations of both PM and RCS. A day-to-day variation was found, probably caused by differences in drilling activities. Preventive measures are warranted to keep the exposure to PM and consequently the exposure to RCS as low as possible to protect the health of workers in tunnel construction.

Cyanobacteria, cyanotoxins and lipopolysaccharides in aerosols from inland freshwater bodies and their effects on human bronchial cells

Components of cyanobacterial water blooms were quantified in aerosols above agitated water surfaces of five freshwater bodies. The thoracic and respirable aerosol fraction (0.1–10 µm) was sampled using a high-volume sampler. Cyanotoxins microcystins were detected by LC-MS/MS at levels 0.3–13.5 ng/mL (water) and < 35–415 fg/m3 (aerosol). Lipopolysaccharides (endotoxins) were quantified by Pyrogene rFC assay at levels < 10–119 EU/mL (water) and 0.13–0.64 EU/m3 (aerosol). Cyanobacterial DNA was detected by qPCR at concentrations corresponding to 104–105 cells eq./mL (water) and 101–103 cells eq./m3 (aerosol). Lipopolysaccharides isolated from bloom samples induced IL-6 and IL-8 cytokine release in human bronchial epithelial cells Beas-2B, while extracted cyanobacterial metabolites induced both pro-inflammatory and cytotoxic effects. Bloom components detected in aerosols and their bioactivities observed in upper respiratory airway epithelial cells together indicate that aerosols formed during cyanobacterial water blooms could induce respiratory irritation and inflammatory injuries, and thus present an inhalation health risk.

Efficacy of dental evacuation systems for aerosol exposure mitigation in dental clinic settings

Dental personnel are ranked among the highest risk occupations for exposure to SARS-CoV-2 due to their close proximity to the patient’s mouth and many aerosol generating procedures encountered in dental practice. One method to reduce aerosols in dental settings is the use of intraoral evacuation systems. Intraoral evacuation systems are placed directly into a patient’s mouth and maintain a dry field during procedures by capturing liquid and aerosols. Although multiple intraoral dental evacuation systems are commercially available, the efficacy of these systems is not well understood. The objectives of this study were to evaluate the efficacy of four dental evacuation systems at mitigating aerosol exposures during simulated ultrasonic scaling and crown preparation procedures. We conducted real-time respirable (PM4) and thoracic (PM10) aerosol sampling during ultrasonic scaling and crown preparation procedures while using four commercially available evacuation systems: a high-volume evacuator (HVE) and three alternative intraoral systems (A, B, C). Four trials were conducted for each system. Respirable and thoracic mass concentrations were measured during procedures at three locations including (1) near the breathing zone (BZ) of the dentist, (2) edge of the dental operatory room approximately 0.9 m away from the mannequin mouth, and (3) hallway supply cabinet located approximately 1.5 m away from the mannequin mouth. Respirable and thoracic mass concentrations measured during each procedure were compared with background concentrations measured in each respective location. Use of System A or HVE reduced thoracic (System A) and respirable (HVE) mass concentrations near the dentist’s BZ to median background concentrations most often during the ultrasonic scaling procedure. During the crown preparation, use of System B or HVE reduced thoracic (System B) and respirable (HVE or System B) near the dentist’s BZ to median background concentrations most often. Although some differences in efficacy were noted during each procedure and aerosol size fraction, the difference in median mass concentrations among evacuation systems was minimal, ranging from 0.01 to 1.48 µg/m3 across both procedures and aerosol size fractions.

Severe lung disease characterized by lymphocytic bronchiolitis, alveolar ductitis, and emphysema (BADE) in industrial machine-manufacturing workers.

A cluster of severe lung disease occurred at a manufacturing facility making industrial machines. We aimed to describe disease features and workplace exposures. Clinical, functional, radiologic, and histopathologic features were characterized. Airborne concentrations of thoracic aerosol, metalworking fluid, endotoxin, metals, and volatile organic compounds were measured. Facility airflow was assessed using tracer gas. Process fluids were examined using culture, polymerase chain reaction, and 16S ribosomal RNA sequencing. Five previously healthy male never-smokers, ages 27 to 50, developed chest symptoms from 1995 to 2012 while working in the facility's production areas. Patients had an insidious onset of cough, wheeze, and exertional dyspnea; airflow obstruction (mean FEV1 = 44% predicted) and reduced diffusing capacity (mean = 53% predicted); and radiologic centrilobular emphysema. Lung tissue demonstrated a unique pattern of bronchiolitis and alveolar ductitis with B-cell follicles lacking germinal centers, and significant emphysema for never-smokers. All had chronic dyspnea, three had a progressive functional decline, and one underwent lung transplantation. Patients reported no unusual nonoccupational exposures. No cases were identified among nonproduction workers or in the community. Endotoxin concentrations were elevated in two air samples; otherwise, exposures were below occupational limits. Air flowed from areas where machining occurred to other production areas. Metalworking fluid primarily grew Pseudomonas pseudoalcaligenes and lacked mycobacterial DNA, but 16S analysis revealed more complex bacterial communities. This cluster indicates a previously unrecognized occupational lung disease of yet uncertain etiology that should be considered in manufacturing workers (particularly never-smokers) with airflow obstruction and centrilobular emphysema. Investigation of additional cases in other settings could clarify the cause and guide prevention.

Job Tasks as Determinants of Thoracic Aerosol Exposure in the Cement Production Industry

The aims of this study were to identify important determinants and investigate the variance components of thoracic aerosol exposure for the workers in the production departments of European cement plants. Personal thoracic aerosol measurements and questionnaire information (Notø et al., 2015) were the basis for this study. Determinants categorized in three levels were selected to describe the exposure relationships separately for the job types production, cleaning, maintenance, foreman, administration, laboratory, and other jobs by linear mixed models. The influence of plant and job determinants on variance components were explored separately and also combined in full models (plant&job) against models with no determinants (null). The best mixed models (best) describing the exposure for each job type were selected by the lowest Akaike information criterion (AIC; Akaike, 1974) after running all possible combination of the determinants. Tasks that significantly increased the thoracic aerosol exposure above the mean level for production workers were: packing and shipping, raw meal, cement and filter cleaning, and de-clogging of the cyclones. For maintenance workers, time spent with welding and dismantling before repair work increased the exposure while time with electrical maintenance and oiling decreased the exposure. Administration work decreased the exposure among foremen. A subjective tidiness factor scored by the research team explained up to a 3-fold (cleaners) variation in thoracic aerosol levels. Within-worker (WW) variance contained a major part of the total variance (35-58%) for all job types. Job determinants had little influence on the WW variance (0-4% reduction), some influence on the between-plant (BP) variance (from 5% to 39% reduction for production, maintenance, and other jobs respectively but an 79% increase for foremen) and a substantial influence on the between-worker within-plant variance (30-96% for production, foremen, and other workers). Plant determinants had little influence on the WW variance (0-2% reduction), some influence on the between-worker variance (0-1% reduction and 8% increase), and considerable influence on the BP variance (36-58% reduction) compared to the null models. Some job tasks contribute to low levels of thoracic aerosol exposure and others to higher exposure among cement plant workers. Thus, job task may predict exposure in this industry. Dust control measures in the packing and shipping departments and in the areas of raw meal and cement handling could contribute substantially to reduce the exposure levels. Rotation between low and higher exposed tasks may contribute to equalize the exposure levels between high and low exposed workers as a temporary solution before more permanent dust reduction measures is implemented. A tidy plant may reduce the overall exposure for almost all workers no matter of job type.

Thoracic and respirable aerosol fractions of spray products containing non-volatile compounds

ABSTRACTA versatile and simple mass balance method for the measurement of the release fraction of thoracic and respirable particles of non-volatile compounds of spray products is presented. The release fractions are defined as the ratio between the mass of suspended non-volatile particulate matter in the thoracic and respirable particle size range and the total mass of non-volatile material released with the spray action. For its determination, a spray bolus of short duration and of defined mass is sprayed into a well stirred control chamber. The respirable and thoracic aerosol mass associated with the spray bolus is determined by measuring the time averaged mass concentration inside the control volume and the half time of the exponential concentration decrease to be expected in well stirred systems to correct for mass losses during sampling. The method is used for a wide range of spray products and technologies for which the release fractions vary by orders of magnitude. A set of data is presented elucidating the relationship between spray technology and fine particle release. Furthermore, a simple rule of thumb was derived from the data that allows for estimation of the release fractions based on a characteristic diameter of the spray droplets. The usefulness of the mass balance method for substance classification as well as for generating input data for exposure assessment and indoor air quality modeling is discussed.

Sampling Efficiency and Performance of Selected Thoracic Aerosol Samplers.

Measurement of worker exposure to a thoracic health-related aerosol fraction is necessary in a number of occupational situations. This is the case of workplaces with atmospheres polluted by fibrous particles, such as cotton dust or asbestos, and by particles inducing irritation or bronchoconstriction such as acid mists or flour dust. Three personal and two static thoracic aerosol samplers were tested under laboratory conditions. Sampling efficiency with respect to particle aerodynamic diameter was measured in a horizontal low wind tunnel and in a vertical calm air chamber. Sampling performance was evaluated against conventional thoracic penetration. Three of the tested samplers performed well, when sampling the thoracic aerosol at nominal flow rate and two others performed well at optimized flow rate. The limit of flow rate optimization was found when using cyclone samplers.

Thoracic dust exposure is associated with lung function decline in cement production workers.

We hypothesised that exposure to workplace aerosols may lead to lung function impairment among cement production workers.Our study included 4966 workers in 24 cement production plants. Based on 6111 thoracic aerosol samples and information from questionnaires we estimated arithmetic mean exposure levels by plant and job type. Dynamic lung volumes were assessed by repeated spirometry testing during a mean follow-up time of 3.5 years (range 0.7–4.6 years). The outcomes considered were yearly change of dynamic lung volumes divided by the standing height squared or percentage of predicted values. Statistical modelling was performed using mixed model regression. Individual exposure was classified into quintile levels limited at 0.09, 0.89, 1.56, 2.25, 3.36, and 14.6 mg·m−3, using the lowest quintile as the reference. Employees that worked in administration were included as a second comparison group.Exposure was associated with a reduction in forced expiratory volume in 1 s (FEV1), forced expiratory volume in 6 s and forced vital capacity. For FEV1 % predicted a yearly excess decline of 0.84 percentage points was found in the highest exposure quintile compared with the lowest.Exposure at the higher levels found in this study may lead to a decline in dynamic lung volumes. Exposure reduction is therefore warranted.

Relationships between Personal Measurements of 'Total' Dust, Respirable, Thoracic, and Inhalable Aerosol Fractions in the Cement Production Industry.

The aims of this study were to examine the relationships and establish conversion factors between 'total' dust, respirable, thoracic, and inhalable aerosol fractions measured by parallel personal sampling on workers from the production departments of cement plants. 'Total' dust in this study refers to aerosol sampled by the closed face 37-mm Millipore filter cassette. Side-by-side personal measurements of 'total' dust and respirable, thoracic, and inhalable aerosol fractions were performed on workers in 17 European and Turkish cement plants. Simple linear and mixed model regressions were used to model the associations between the samplers. The total number of personal samples collected on 141 workers was 512. Of these 8.4% were excluded leaving 469 for statistical analysis. The different aerosol fractions contained from 90 to 130 measurements and-side-by side measurements of all four aerosol fractions were collected on 72 workers.The median ratios between observed results of the respirable, 'total' dust, and inhalable fractions relative to the thoracic aerosol fractions were 0.51, 2.4, and 5.9 respectively. The ratios between the samplers were not constant over the measured concentration range and were best described by regression models. Job type, position of samplers on left or right shoulder and plant had no substantial effect on the ratios. The ratios between aerosol fractions changed with different air concentrations. Conversion models for estimation of the fractions were established. These models explained a high proportion of the variance (74-91%) indicating that they are useful for the estimation of concentrations based on measurements of a different aerosol fraction. The calculated uncertainties at most observed concentrations were below 30% which is acceptable for comparison with limit values (EN 482, 2012). The cement industry will therefore be able to predict the health related aerosol fractions from their former or future measurements of one of the fractions.

Short-term lung function decline in tunnel construction workers

ObjectivesTunnel construction workers are exposed to particulate and gaseous air contaminants. Previous studies carried out in the 1990s showed that tunnel construction workers were at increased risk of both short-term...

Exposure to thoracic aerosol in a prospective lung function study of cement production workers.

An exposure study was conducted as part of a multi-national longitudinal study of lung function in cement production workers. To examine exposure to thoracic aerosol among cement production workers during a 4-year follow-up period. Personal shift measurements of thoracic aerosol were conducted among the cement production workers within seven job types, 22 plants, and eight European countries (including Turkey) in 2007, 2009, and 2011. The thoracic sub-fraction was chosen as the most relevant aerosol fraction related to obstructive dynamic lung function changes. Production factors, job type, and respirator use were recorded by questionnaire. The exposure data were log-transformed before mixed models analysis and results were presented by geometric mean (GMadj) exposure levels adjusted for plant or job type, worker, and season as random effects. A total of 6111 thoracic aerosol samples were collected from 2534 workers. Repeated measurements were obtained from 1690 of these workers. The GMadj thoracic aerosol levels varied between job types from 0.20 to 1.2mg m(-3). The highest exposure levels were observed for production, cleaning, and maintenance workers (0.79-1.2mg m(-3)) and could reach levels where the risk of lung function loss may be increased. The lowest levels were found for administrative personnel (0.20mg m(-3)) serving tasks in the production areas. Office work was not monitored. GMadj exposure levels between plants ranged from 0.19 to 2.0mg m(-3). The time of year/season contributed significantly to the total variance, but not year of sampling. Production characteristics explained 63% of the variance explained by plant. Workers in plants with the highest number of employees (212-483 per plant) were exposed at a level more than twice as high as those in plants with fewer employees. Other production factors such as cement production, bag filling, and tidiness were significant, but explained less of the exposure variability. These determinants factors can be useful in qualitative exposure assessment and exposure prevention in the cement production industry. Respirator use was minor at exposure levels <0.5mg m(-3) but more common at higher levels. Production, cleaning, and maintenance work were the job types with highest exposure to thoracic aerosol in cement production plants. However, plant had an even larger effect on exposure levels than job type. The number of employees was the most important factor explaining differences between plants. Exposure reached levels where the risk of lung function loss may be increased. No significant differences in exposure between sampling campaigns were observed during the 4-year study period.

Characterization of occupational exposure to air contaminants in modern tunnelling operations.

Personal air measurements of aerosols and gases among tunnel construction workers were performed as part of a 11-day follow-up study on the relationship between exposure to aerosols and gases and cardiovascular and respiratory effects. Ninety tunnel construction workers employed at 11 available construction sites participated in the exposure study. The workers were divided into seven job groups according to tasks performed. Exposure measurements were carried out on 2 consecutive working days prior to the day of health examination. Summary statistics were computed using maximum likelihood estimation (MLE), and the procedure NLMIXED and LIFEREG in SAS was used to perform MLE for repeated measures data subject to left censoring and for calculation of within- and between-worker variance components. The geometric mean (GM) air concentrations for the thoracic mass aerosol sub-fraction, α-quartz, oil mist, organic carbon (OC), and elemental carbon (EC) for all workers were 561, 63, 210, 146, and 35.2 μg m(-3), respectively. Statistical differences of air concentrations between job groups were observed for all contaminants, except for OC, EC, and ammonia (P > 0.05). The shaft drillers, injection workers, and shotcreting operators were exposed to the highest GM levels of thoracic dust (7061, 1087, and 865 μg m(-) (3), respectively). The shaft drillers and the support workers were exposed to the highest GM levels of α-quartz (GM = 844 and 118 μg m(-3), respectively). Overall, the exposure to nitrogen dioxide and ammonia was low (GM = 120 and 251 μg m(-) (3), respectively). Findings from this study show significant differences between job groups with shaft drilling as the highest exposed job to air concentrations for all measured contaminants. Technical interventions in this job should be implemented to reduce exposure levels. Overall, diesel exhaust air concentrations seem to be lower than previously assessed (as EC).

Longitudinal decline in pulmonary diffusing capacity among nitrate fertilizer workers

This study is part of a 3-year follow-up of lung function among nitrate fertilizer production workers. To study the possible adverse effects of occupational exposure to aerosols and gases on pulmonary diffusing capacity. A longitudinal study of a cohort of fertilizer workers who performed single-breath carbon monoxide diffusing capacity (DLco) tests and spirometry in 2007 and 2010. The workers completed a questionnaire on respiratory symptoms and smoking habits. Exposure to mineral dust, acid aerosols and inorganic gases was measured. The overall median inhalable and thoracic aerosol mass concentrations were 1.1mg/m(3) (min-max: <0.93-45) and 0.21mg/m(3) (min-max: <0.085-11), respectively. There were 308 participants in 2007 with 168 returning subjects in 2010. Overall, we found a statistically significant decline in the DLco of 0.068 mmol/min/kPa/year, adjusted for gender, age, height, weight, smoking status and doctor-diagnosed asthma during the 3-year follow-up (P < 0.01). The change in DLco did not vary significantly between the various job groups. Subjects with respiratory symptoms did not show a larger decline in DLco than those without symptoms. This study indicates a larger than expected decline in the DLco of fertilizer workers during a 3-year follow-up. However, the decline was not related to specific exposures at work, or to possible covariates of exposure.

320 Exposure assessment of thoracic aerosol in an international prospective study of cement production workers

Hilde Notø, Karl-Christian Nordby, �’ivind Skare, Helge Kjuus and Wijnand EduardBackground and ObjectivesRespiratory effects have been linked to aerosol exposure in cement production workers. This presentation aims at estimating annual...

411 Prospective monitoring of exposure and lung function among cement production workers - An international study

ObjectivesIn this longitudinal study we aimed to estimate the longitudinal fall in forced expiratory volume at one second (FEV1) associated with different levels of thoracic aerosol exposure in cement production...

Intersampler Field Comparison of Respicon&lt;sup&gt;®&lt;/sup&gt;, IOM, and Closed-Face 25-mm Personal Aerosol Samplers During Primary Production of Aluminium

Intersampler field comparison of Respicon(®), 25-mm closed-face 'total dust' cassette (CFC), and IOM inhalable aerosol sampler was conducted in pot rooms at seven aluminium smelters. The aerosol mass and water-soluble fluoride were selected as airborne contaminants for the comparisons. The aerosol masses of 889 sample pairs of IOM and Respicon(®) inhalable aerosol sub-fraction, 165 of IOM and 25-mm CFC, and 194 of CFC and Respicon(®) thoracic aerosol sub-fraction were compared. The number of sample pairs for the comparison of water-soluble fluoride was 906, 170, and 195, respectively. The geometric mean aerosol mass collected with the inhalable Respicon(®) was 2.91 mg m(-3) compared with 3.38 mg m(-3) with the IOM. The overall ratio between IOM and Respicon(®) inhalable sub-fraction was 1.16 [95% confidence interval (CI) = 1.11-1.21] for aerosol mass and 1.13 (95% CI = 1.08-1.18) for water-soluble fluoride. The results indicate that Respicon(®) undersampled the aerosol mass and water-soluble fluoride in the inhalable sub-fraction compared with the IOM. The results indicated undersampling of the Respicon(®) at mass concentrations higher than 1.35 mg m(-3) and oversampling at lower mass concentrations. The overall ratio between aerosol mass collected with IOM and CFC was 4.19 (95% CI = 3.79-4.64) and 1.61 (95% CI = 1.51-1.72) for water-soluble fluoride. Thus, for this industry, a correction factor of 4.2 is suggested for the conversion of CFC to inhalable aerosol masses and a conversion factor of 1.6 for water-soluble fluoride if wall deposits in the CFC are included. CFC and thoracic Respicon(®) collected similar aerosol masses (ratio = 1.04; 95% CI = 0.97-1.12), whereas the ratio was 1.19 (95% CI = 1.11-1.28) for water-soluble fluoride. The variability of the exposure is substantial; thus, large data sets are required in sampler performance field comparisons.

Longitudinal lung function decline among workers in a nitrate fertilizer production plant

This study examines the possible effect of exposure to aerosols and gases on lung function in a fertilizer plant in Norway. Dynamic lung volumes (FVC and FEV1) of 383 workers were measured in 2007 and 2010. During the follow-up period, most workers performed tasks with low exposure levels of acid aerosols and inorganic gases. The overall median inhalable and thoracic aerosol exposure levels were 1·1 and 0·21 mg/m(3), respectively. A questionnaire on respiratory symptoms was provided. During the follow-up period, there was an adjusted decrease of FEV1 of 18 ml/year (P<0·001). The respiratory symptoms score was low during follow-up. Work in this fertilizer industry may lead to an excessive lung function decline. We have, however, not been able to find any plausible exposure related explanation for the overall lung function decline.

Occupational exposure to beryllium in primary aluminium production

Alumina used in the production of primary aluminium contains Be which partly vaporises from the cryolite bath into the workroom atmosphere. Since Be may be toxic at lower exposure levels than previously thought, the personal exposure to Be among workers in 7 Norwegian primary smelters has been assessed. In total, 480 personal Respicon® virtual impactor full shift air samples have been collected during 2 sampling campaigns and analysed for water soluble Be, Al and Na using inductively coupled plasma optical emission spectrometry. In addition, water soluble F(-) has been measured by ion chromatography. The Be air concentrations in the inhalable, thoracic and respirable aerosol fractions have been calculated. The Be concentrations in the inhalable aerosol fraction vary between the different smelters. The highest GM concentration of Be in the inhalable fraction (122 ng m(-3), n = 30) was measured in the prebake pot room of a smelter using predominantly Jamaican alumina where also the highest individual air concentration of 270 ng m(-3) of Be was identified. The relative distribution of Be in the different aerosol fractions was fairly constant with the mean Be amount for the two sampling campaigns between 44-49% in the thoracic fraction expressed as % of the inhalable amount. Linear regression analysis shows a high correlation between water soluble Be, Al, F and Na describing an average measured chemical bulk composition of the water soluble thoracic fraction as Na(5.7)Al(3.1)F(18). Be is likely to be present as traces in this particulate matter by replacing Al atoms in the condensed fluorides and/or as a major element in a nanoparticle sized fluoride. Thus, the major amount of Be present in the work room atmosphere of Al smelter pot rooms will predominantly be present in combination with substantial amounts of water soluble Al, F and Na.

Characterisation of occupational exposure to air contaminants in a nitrate fertiliser production plant

The aim of this study was to characterise personal exposures to dust, acid vapours, and gases among workers in a Norwegian nitrate fertiliser production plant, as part of an ongoing epidemiological study. In total, 178 inhalable and 179 thoracic aerosol mass fraction samples were collected from randomly chosen workers (N = 141) from three compound fertiliser departments (A, B and C), a calcium nitrate fertiliser production department, nitric acid- and ammonia-production departments, and a shipping department. The overall median inhalable and thoracic aerosol mass concentrations were generally low (1.1 mg m(-3) (min-max: <0.93-45) and 0.21 mg m(-3) (min-max: <0.085-11), respectively). Workers at the compound fertiliser departments B and C had significantly higher inhalable aerosol mass air concentrations compared to the other departments (p < 0.05), except for compound fertiliser department A; however, the difference between the compound fertiliser department C and calcium nitrate department was slightly above the significant level. Workers at the compound fertiliser department A had significantly higher thoracic aerosol mass air concentrations compared to the other departments (p < 0.05), except for compound fertiliser departments B and C. The results indicate that the extrathoracic aerosol fraction of the aerosol compared to the thoracic fraction dominated in most departments. Measurement of the main constituents Ca, K, Mg, and P in the water-soluble and water-insoluble aerosol mass fractions showed that the air concentrations of these elements were low. There is, however, a shift towards more water-soluble species as the production goes from raw material with phosphate rock towards the final product of fertilisers. Overall, the arithmetic mean of water-soluble Ca in the thoracic mass fraction was 51% (min-max: 1-100). A total of 169 personal samples were analysed for HNO(3) vapour and HF. The highest median concentration of HNO(3) (0.63 mg m(-3)) was in the compound fertiliser departments B, and all measurements but four of the HF concentrations were below the LOD of 190 μg m(-3). Exposures to NH(3), CO and NO(2) were measured using direct-reading electrochemical sensors and the time weighted overall averages were all below the LODs of the respective sensors, NH(3) 2 ppm; CO 2 ppm; and NO(2) 0.2 ppm, but some short-term peaks were detected. Even though our results indicate that the workers may experience peak exposure episodes when performing job tasks such as cleaning or maintenance work, the overall air concentrations are well below what is considered to cause known health risks.