| 1. |
- Ali, Neserin, et al.
(author)
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Comprehensive proteome analysis of nasal lavage samples after controlled exposure to welding nanoparticles shows an induced acute phase and a nuclear receptor, LXR/RXR, activation that influence the status of the extracellular matrix
- 2018
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In: Clinical Proteomics. - : Springer Science and Business Media LLC. - 1542-6416 .- 1559-0275. ; 15:1
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Journal article (peer-reviewed)abstract
- Background: Epidemiological studies have shown that many welders experience respiratory symptoms. During the welding process a large number of airborne nanosized particles are generated, which might be inhaled and deposited in the respiratory tract. Knowledge of the underlying mechanisms behind observed symptoms is still partly lacking, although inflammation is suggested to play a central role. The aim of this study was to investigate the effects of welding fume particle exposure on the proteome expression level in welders suffering from respiratory symptoms, and changes in protein mediators in nasal lavage samples were analyzed. Such mediators will be helpful to clarify the pathomechanisms behind welding fume particle-induced effects. Methods: In an exposure chamber, 11 welders with work-related symptoms in the lower airways during the last month were exposed to mild-steel welding fume particles (1 mg/m3) and to filtered air, respectively, in a double-blind manner. Nasal lavage samples were collected before, immediately after, and the day after exposure. The proteins in the nasal lavage were analyzed with two different mass spectrometry approaches, label-free discovery shotgun LC-MS/MS and a targeted selected reaction monitoring LC-MS/MS analyzing 130 proteins and four in vivo peptide degradation products. Results: The analysis revealed 30 significantly changed proteins that were associated with two main pathways; activation of acute phase response signaling and activation of LXR/RXR, which is a nuclear receptor family involved in lipid signaling. Connective tissue proteins and proteins controlling the degradation of such tissues, including two different matrix metalloprotease proteins, MMP8 and MMP9, were among the significantly changed enzymes and were identified as important key players in the pathways. Conclusion: Exposure to mild-steel welding fume particles causes measurable changes on the proteome level in nasal lavage matrix in exposed welders, although no clinical symptoms were manifested. The results suggested that the exposure causes an immediate effect on the proteome level involving acute phase proteins and mediators regulating lipid signaling. Proteases involved in maintaining the balance between the formation and degradation of extracellular matrix proteins are important key proteins in the induced effects.
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| 2. |
- Andersen, Christina, et al.
(author)
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Inhalation and dermal uptake of particle and gas phase phthalates - A human chamber exposure study
- 2018
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In: 15th Conference of the International Society of Indoor Air Quality and Climate, INDOOR AIR 2018. - 9781713826514
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Conference paper (peer-reviewed)abstract
- We have exposed sixteen test subjects to particle and gas phase phthalates in the controlled chamber exposure study. Deuterium labelled phthalates were used to generate particle D4-DEHP (di(2-ethylhexyl) phthalate) and gas phase D4-DEP (diethyl phthalate) for exposures scenarios allowed studying the dermal only and combined inhalational and dermal uptake. Metabolites were measured in urine samples before and after three hours of exposure. The inhalation was the dominant route of uptake for both DEHP and DEP in this study design and exposure settings. Larger uptake of DEP compared to DEHP both via inhalation and dermal uptake was observed. Dermal uptake of DEHP was not observed in this study. Inhalational urinary excretion factors of the metabolites were found to be 0.73 for DEHP and 0.53 for DEP. This study also highlights the importance of taking into consideration the deposited dose of inhaled particles in studies of uptake of particles.
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| 3. |
- Andersen, Christina, et al.
(author)
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Inhalation and Dermal Uptake of Particle and Gas-phase Phthalates - A Human Exposure Study
- 2018
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In: Environmental Science & Technology. - : American Chemical Society (ACS). - 1520-5851 .- 0013-936X. ; 52:21, s. 12792-12800
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Journal article (peer-reviewed)abstract
- Phthalates are ubiquitous in indoor environments, which raises concern about their endocrine disrupting properties. However, studies of human uptake from airborne exposure are limited. We studied the inhalation uptake and dermal uptake by air-to-skin transfer with clean clothing as a barrier of two deuterium-labelled airborne phthalates: particle-phase D4-DEHP (di-(2-ethylhexyl)phthalate) and gas-phase D4-DEP (diethyl phthalate). Sixteen participants, wearing trousers and long-sleeved shirts, were under controlled conditions exposed to airborne phthalates in four exposure scenarios: dermal uptake alone, and combined inhalation+dermal uptake of both phthalates. The results showed an average uptake of D4-DEHP by inhalation of 0.0014±0.00088 (µg kg-1 bw)/(µg m-3)/h. No dermal uptake of D4-DEHP was observed during the 3 hour exposure with clean clothing. The deposited dose of D4-DEHP accounted for 26% of the total inhaled D4-DEHP mass. For D4-DEP, the average uptake by inhalation+dermal was 0.0067±0.0045 and 0.00073±0.00051 (µg kg-1 bw)/(µg m-3)/h for dermal uptake. Urinary excretion factors of metabolites after inhalation were estimated to 0.69 for D4-DEHP and 0.50 for D4-DEP. Under the described settings, the main uptake of both phthalates was through inhalation. The results demonstrate the differences in uptake of gas and particles, and highlights the importance of considering the deposited dose in particle uptake studies.
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| 4. |
- Beko, Gabriel, et al.
(author)
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Contribution of various microenvironments to the daily personal exposure to ultrafine particles: Personal monitoring coupled with GPS tracking
- 2015
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In: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 110, s. 122-129
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Journal article (peer-reviewed)abstract
- Exposure to ultrafine particles (UFP) may have adverse health effects. Central monitoring stations do not represent the personal exposure to UFP accurately. Few studies have previously focused on personal exposure to UFP. Sixty non-smoking residents living in Copenhagen, Denmark were asked to carry a backpack equipped with a portable monitor, continuously recording particle number concentrations (PN), in order to measure the real-time individual exposure over a period of similar to 48 h. A GPS logger was carried along with the particle monitor and allowed us to estimate the contribution of UFP exposure occurring in various microenvironments (residence, during active and passive transport, other indoor and outdoor environments) to the total daily exposure. On average, the fractional contribution of each microenvironment to the daily integrated personal exposure roughly corresponded to the fractions of the day the subjects spent in each microenvironment. The home environment accounted for 50% of the daily personal exposure. Indoor environments other than home or vehicles contributed with similar to 40%. The highest median UFP concentration was obtained during passive transport (vehicles). However, being in transit or outdoors contributed 5% or less to the daily exposure. Additionally, the subjects recorded in a diary the periods when they were at home. With this approach, 66% of the total daily exposure was attributable to the home environment. The subjects spent 28% more time at home according to the diary, compared to the GPS. These results may indicate limitations of using diaries, but also possible inaccuracy and miss-classification in the GPS data. (C) 2015 Elsevier Ltd. All rights reserved.
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| 5. |
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| 6. |
- Dierschke, Katrin, et al.
(author)
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Acute respiratory effects and biomarkers of inflammation due to welding-derived nanoparticle aggregates
- 2017
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In: International Archives of Occupational and Environmental Health. - : Springer Science and Business Media LLC. - 0340-0131 .- 1432-1246. ; 90:5, s. 451-463
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Journal article (peer-reviewed)abstract
- Welders are exposed to airborne particles from the welding environment and often develop symptoms work-related from the airways. A large fraction of the particles from welding are in the nano-size range. In this study we investigate if the welders' airways are affected by exposure to particles derived from gas metal arc welding in mild steel in levels corresponding to a normal welding day. In an exposure chamber, 11 welders with and 10 welders without work-related symptoms from the lower airways and 11 non-welders without symptoms, were exposed to welding fumes (1 mg/m(3)) and to filtered air, respectively, in a double-blind manner. Symptoms from eyes and upper and lower airways and lung function were registered. Blood and nasal lavage (NL) were sampled before, immediately after and the morning after exposure for analysis of markers of oxidative stress. Exhaled breath condensate (EBC) for analysis of leukotriene B4 (LT-B4) was sampled before, during and immediately after exposure. No adverse effects of welding exposure were found regarding symptoms and lung function. However, EBC LT-B4 decreased significantly in all participants after welding exposure compared to filtered air. NL IL-6 increased immediately after exposure in the two non-symptomatic groups and blood neutrophils tended to increase in the symptomatic welder group. The morning after, neutrophils and serum IL-8 had decreased in all three groups after welding exposure. Remarkably, the symptomatic welder group had a tenfold higher level of EBC LT-B4 compared to the two groups without symptoms. Despite no clinical adverse effects at welding, changes in inflammatory markers may indicate subclinical effects even at exposure below the present Swedish threshold limit (8 h TWA respirable dust).
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| 7. |
- Eriksson, Axel C., et al.
(author)
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The role of organic fraction of aerosol particles in uptake of indoor SVOC investigated with real time aerosol mass spectrometry
- 2018
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In: 15th Conference of the International Society of Indoor Air Quality and Climate, INDOOR AIR 2018. - 9781713826514
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Conference paper (peer-reviewed)abstract
- We investigate the uptake of the Di(2-ethylhexyl) phthalate (DEHP) by laboratory generated and ambient aerosol particles passing through a 1.2 liter chamber covered with vinyl flooring on its internal surfaces. We found approximately five times more efficient DEHP uptake on a mass basis by organic particles (ambient particles) compared to laboratory generated salt particles. The increased uptake is likely due to increased adsorption by pre-existing organic aerosol, which is abundant in the ambient aerosol particles. This implies that compounds with adverse health outcomes are added to particles in indoor air after infiltration into buildings via gas-to-particle conversion of indoor generated SVOCs. We show that aerosol mass spectrometry is a suitable tool for highly time-resolved investigations of this process.
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| 8. |
- Hedmer, Maria, et al.
(author)
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Diesel Exhaust Exposure Assessment Among Tunnel Construction Workers—Correlations Between Nitrogen Dioxide, Respirable Elemental Carbon, and Particle Number
- 2017
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In: Annals of Work Exposures and Health. - : Oxford University Press (OUP). - 2398-7308 .- 2398-7316. ; 61:5, s. 539-553
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Journal article (peer-reviewed)abstract
- Objectives: Occupational exposure to diesel exhaust is common due the widespread use of dieselpowered combustion engines. Diesel exhaust is chemically complex and consists of thousands of compounds present as gases and particulate matter. Both nitrogen dioxide (NO2) and elemental carbon(EC) have been used as markers for diesel exhaust exposure. Currently EC is regarded as the best surrogate of diesel exhaust. The objective was to quantify the occupational exposure to diesel exhaust in underground tunnel construction work using a multi-metric approach, and to investigate the correlations between NO2, respirable EC, respirable organic carbon (OC), respirable total carbon(TC), respirable dust (RD), and particle number. Also, the use of NO2 as a proxy for diesel exhaust was evaluated, how much of the variability in the diesel exhaust exposure was attributed to within and between individual factors and if there was a difference between expert and self-administered measurements of NO2. Methods: The personal exposure to diesel exhaust was assessed by expert supervised measurements of NO2, EC, OC, TC, RD and particle number in the breathing zones of underground tunnel workers. Stationary sampling of NO2, EC, OC, TC, RD, size-fractioned mass concentration, and particle number were conducted. The personal and stationary measurements were conducted on threeoccasions simultaneously. The workers measured their exposure by repeated self-administered measurements of NO2. The self-administered measurements were performed twice for each worker with at least one month lag between the samplings. Results: In the simultaneous sampling of diesel exhaust, the geometric mean (GM) concentration of NO2 and respirable EC were 72 μg m−3 (10th–90th percentile 34–140 μg m−3) and 2.6 μg m−3 (10th–90th percentile 1.6–7.3 μg m−3), respectively. The GM for OC and TC was 28 μg m−3 (10th–90th percentile 20–42 μg m−3) and 31 μg m−3 (10th–90th percentile 20–50 μg m−3), respectively. The GM for RD and particle number was 180 μg m−3 (10th–90th percentile 20–530 μg m−3) and 47 900 cm−3 (10th–90th percentile (27 500–94 100 cm−3), respectively. A significant correlation was found between NO2 and respirable EC [Spearman’s correlation r = 0.53 (P = 0.05)]. The within-worker variability of NO2 was 45.5% and the between-worker variability was 54.5%. The self-administered measured concentrations of NO2 (GM 70 μg m−3) did not statistically differ from the NO2 concentrations measured by an expert (P > 0.35).Conclusion: The diesel exhaust exposure in tunnel construction work was low. A significant correlation between NO2 and EC was observed. This indicates that NO2 could be used as a proxy for diesel exhaust in tunnel work if diesel exhaust is the only source of NO2 and if the ratio between EC and NO2 is known and constant. Passive sampling of NO2 is much easier and cheaper to perform compared with active sampling of EC. It is possible to utilize self-administered NO2 measurements in extreme and inaccessible work environments. This study adds support to continued use of NO2 as an exposure marker in combination with EC for diesel exhaust exposure. In tunnel construction work, the variability in the diesel exhaust exposure was high both between- and within-workers.
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| 9. |
- Hemmingsen, Jette Gjerke, et al.
(author)
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Controlled exposure to diesel exhaust and traffic noise - Effects on oxidative stress and activation in mononuclear blood cells.
- 2015
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In: Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis. - : Elsevier BV. - 1879-2871 .- 0027-5107. ; 775, s. 66-71
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Journal article (peer-reviewed)abstract
- Particulate air pollution increases risk of cancer and cardiopulmonary disease, partly through oxidative stress. Traffic-related noise increases risk of cardiovascular disease and may cause oxidative stress. In this controlled random sequence study, 18 healthy subjects were exposed for 3h to diesel exhaust (DE) at 276μg/m(3) from a passenger car or filtered air, with co-exposure to traffic noise at 48 or 75dB(A). Gene expression markers of inflammation, (interleukin-8 and tumor necrosis factor), oxidative stress (heme oxygenase (decycling-1)) and DNA repair (8-oxoguanine DNA glycosylase (OGG1)) were unaltered in peripheral blood mononuclear cells (PBMCs). No significant differences in DNA damage levels, measured by the comet assay, were observed after DE exposure, whereas exposure to high noise levels was associated with significantly increased levels of hOGG1-sensitive sites in PBMCs. Urinary levels of 8-oxo-7,8-dihydro-2'-deoxyguanosine were unaltered. In auxiliary ex vivo experiments whole blood was incubated with particles from the exposure chamber for 3h without effects on DNA damage in PBMCs or intracellular reactive oxygen species production and expression of CD11b and CD62L adhesion molecules in leukocyte subtypes.
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| 10. |
- Koivisto, Antti Joonas, et al.
(author)
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Source specific exposure and risk assessment for indoor aerosols
- 2019
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In: Science of the Total Environment. - : Elsevier BV. - 0048-9697. ; 668, s. 13-24
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Journal article (peer-reviewed)abstract
- Poor air quality is a leading contributor to the global disease burden and total number of deaths worldwide. Humans spend most of their time in built environments where the majority of the inhalation exposure occurs. Indoor Air Quality (IAQ) is challenged by outdoor air pollution entering indoors through ventilation and infiltration and by indoor emission sources. The aim of this study was to understand the current knowledge level and gaps regarding effective approaches to improve IAQ. Emission regulations currently focus on outdoor emissions, whereas quantitative understanding of emissions from indoor sources is generally lacking. Therefore, specific indoor sources need to be identified, characterized, and quantified according to their environmental and human health impact. The emission sources should be stored in terms of relevant metrics and statistics in an easily accessible format that is applicable for source specific exposure assessment by using mathematical mass balance modelings. This forms a foundation for comprehensive risk assessment and efficient interventions. For such a general exposure assessment model we need 1) systematic methods for indoor aerosol emission source assessment, 2) source emission documentation in terms of relevant a) aerosol metrics and b) biological metrics, 3) default model parameterization for predictive exposure modeling, 4) other needs related to aerosol characterization techniques and modeling methods. Such a general exposure assessment model can be applicable for private, public, and occupational indoor exposure assessment, making it a valuable tool for public health professionals, product safety designers, industrial hygienists, building scientists, and environmental consultants working in the field of IAQ and health.
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