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- Bredberg, Anna, et al.
(författare)
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Analysis of manganese and iron in exhaled endogenous particles
- 2014
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Ingår i: Journal of Analytical Atomic Spectrometry. - 0267-9477 .- 1364-5544. ; 29, s. 730-735
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Tidskriftsartikel (refereegranskat)abstract
- Background: Many full-time welders experience some sort of respiratory disorder e.g., asthma, bronchitis and metal fume fever. Thus, welding aerosols are thought to cause airway inflammation. There is a need for markers of welding aerosols in exposure assessments, and as most welding aerosols contain manganese and iron, these metals may possibly be used as an indicator. We have previously developed a novel non-invasive technique to collect endogenous particles in exhaled air (PEx). This study is designed to i) develop a method for analysis of manganese and iron in PEx and ii) investigate whether the manganese and/or iron content of PEx changes after exposure to welding aerosols. Methods: Nine individuals were experimentally exposed to welding fumes. PEx was collected at three time points for each individual; before, after and 24 hour after exposure. Analyses of PEx samples were performed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Results: Four out of nine individuals showed an increase in manganese and iron levels after exposure to welding aerosols. The mean manganese and iron concentration increased from,
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- Hagerman, Inger, et al.
(författare)
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Effects on heart rate variability by artificially generated indoor nano-sized particles in a chamber study
- 2014
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 88, s. 165-171
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Tidskriftsartikel (refereegranskat)abstract
- Background: Airborne particles are associated with increased morbidity and mortality due to respiratory and cardiovascular diseases in polluted areas. There is a growing interest in nano-sized particles with diameter < 100 nm and their potential health effects. Heart rate variability (HRV) is a noninvasive method for cardiovascular risk prediction in high prevalent groups. Aim of study: The aim was to evaluate the impact of nano-sized indoor air particles on HRV for healthy and adult females. Methods: All exposures were performed as controlled chamber experiments with particle exposure from burning candles, terpene + ozone reactions or filtered air in a double-blind cross over design. Twenty-two healthy females were investigated during 10 min periods at different exposures and the reactivity in high frequency (HF) spectral band of HRV were computed. Results: Heart rate was unchanged from baseline values in all groups during all experimental settings. HF power of HRV tended to increase during exposure to particles from burning candle while particles from terpene + ozone reactions tended to decrease HF power. Conclusions: Exposure to nano-sized particles of burning candles or terpene + ozone reactions results in different patterns of heart rate variability, with signs of altered autonomic cardiovascular control. Practical implications: This study indicates that the HRV method may be used for information on physiological responses of exposure to different nano-sized particles and contribute to the understanding of mechanisms behind health effects of particle exposures. (C) 2014 The Authors. Published by Elsevier Ltd.
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- Hedmer, Maria, et al.
(författare)
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Exposure and Emission Measurements During Production, Purification, and Functionalization of Arc-Discharge-Produced Multi-walled Carbon Nanotubes.
- 2014
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Ingår i: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 1475-3162. ; 58:3, s. 355-379
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Tidskriftsartikel (refereegranskat)abstract
- Background: The production and use of carbon nanotubes (CNTs) is rapidly growing. With increased production, there is potential that the number of occupational exposed workers will rapidly increase. Toxicological studies on rats have shown effects in the lungs, e.g. inflammation, granuloma formation, and fibrosis after repeated inhalation exposure to some forms of multi-walled CNTs (MWCNTs). Still, when it comes to health effects, it is unknown which dose metric is most relevant. Limited exposure data for CNTs exist today and no legally enforced occupational exposure limits are yet established. The aim of this work was to quantify the occupational exposures and emissions during arc discharge production, purification, and functionalization of MWCNTs. The CNT material handled typically had a mean length <5 μm. Since most of the collected airborne CNTs did not fulfil the World Health Organization fibre dimensions (79% of the counted CNT-containing particles) and since no microscopy-based method for counting of CNTs exists, we decided to count all particle that contained CNTs. To investigate correlations between the used exposure metrics, Pearson correlation coefficient was used.
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- Isaxon, Christina, et al.
(författare)
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A Novel System for Source Characterization and Controlled Human Exposure to Nanoparticle Aggregates Generated During Gas–Metal Arc Welding
- 2013
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Ingår i: Aerosol Science and Technology. - : Informa UK Limited. - 1521-7388 .- 0278-6826. ; 47:1, s. 52-59
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in Undetermined The aim of this study was to achieve a method to perform detailed characterization and human exposure studies of nanosized and nanostructured aerosol particles. The source chosen was mild steel, active gas, arc welding fume. The setup consisted of a generation chamber, where welding can be performed, connected to an airtight stainless steel 22 m(3) exposure chamber. Instrumentation, consisting of a tapered element oscillating microbalance, a scanning mobility particle sizer, and a sampler for electron microscopy and particle-induced X-ray emission analysis was connected to the stainless steel chamber. The feasibility of the system for human exposure studies was evaluated by exposing 31 human volunteers, in groups of three, to a test aerosol containing 1 mg/m(3) welding fumes and to conditioned, filtered air. The results show that an aerosol that accurately represents dilute welding fume exposures that occur in workplaces can be produced in a controlled manner, and that the experimental setup can be used for 6 h, double-blind, exposures of human subjects. Particle mass concentration levels could be varied from <5 mu g/m(3) to more than 1000 mu g/m(3). Fumes from metal active gas welding showed a unimodal size distribution with a mean mobility diameter of 160 nm, transmission electron microscopy showed aggregates with a clearly nanosized structure.
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| 13. |
- Isaxon, Christina
(författare)
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Aerosol characterization in real life and a methodology for human exposure studies in controlled chamber settings
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Airborne particles are everywhere around us, and have always been. Particles generated by human activities has increased drastically since industrialization, and several epidemiological studies have shown that inhaled particles can cause adverse health effects. The concern about health effects have during the last decade shifted towards fine and ultrafine particles, not least due to the emerging field of nanotechnology. Of special interest are the particles to which we are exposed indoors – in the industrialized part of the world we spend around 90% of our time indoors (at home and at workplaces/schools). Particles generated in these environments often cause intense peaks in concentration, and are often consequences of our own activities. Especially combustion/thermal processes (such as welding, frying, burning candles etc.) cause peaks in number concentration, often more than an order of magnitude higher than ambient concentrations. We have conducted time-resolved particle measurements in several homes which confirm this. From these measurements, we have been able to show just how much occupants' activities affect the indoor concentration of ultrafine particles compared to outdoor concentrations. We have also estimated e.g. total integrated daily exposure. Exposure and emission measurements have also been conducted at a carbon nanotube producing facility, and a method for counting particles containing carbon nanotubes has been suggested and validated. Why certain particles are more dangerous than others is often investigated in animal exposure studies, where exposure levels are unrealistically high. For several reasons, the results of such studies are not simple to translate to the human system. To increase our understanding of which particle properties can cause effects in humans, a methodology for conducting human exposure studies have been developed and validated. In a controlled chamber we have exposed human test subjects to normal concentrations of common particle types; candle smoke, particles from terpene–ozone reactions and welding fume. Together with medical expertise, we have been looking for effects of these exposures. By using non-invasive tests (e.g. urine and blood samples and ECG) biochemical markers of exposure, and changes in heart rate variability (HRV) have been studied. A significant increase in the high frequency domain of the HRV during exopsure for candle smoke was found.
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- Isaxon, Christina, et al.
(författare)
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Realistic indoor nano-aerosols for a human exposure facility
- 2013
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Ingår i: Journal of Aerosol Science. - : Elsevier BV. - 0021-8502. ; 60, s. 55-66
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to achieve realistic levels of two different types of aerosols commonly abundant in indoor environments in an experimental chamber intended for human exposure studies and aerosol characterization. The aerosols chosen were particles from candle lights (in particle number dominated by inorganic water soluble particles) and from ozone-terpene reactions (organic particles). The aerosol generation and characterization system consisted of a controlled air tight stainless steel 22 m(3) chamber, to which the generation set-ups were connected. No air could enter or leave the chamber except through a conditioning system by which temperature, relative humidity and air exchange rate could be controlled. Candle smoke aerosol was generated from ten candles burning in a 1.33 m(3) glass and stainless steel chamber. The aerosol was diluted by clean air from the conditioning system before entering the chamber. Terpene vapor was generated by passing pure nitrogen through a glass bottle containing limonene oil. Ozone was generated by a spark discharge using pure O-2, and was added to the ventilation air flow downstream the inlet for terpene vapors and upstream the inlet to the chamber. Both aerosols were characterized with respect to number and mass concentrations, size distribution and chemical composition. Particle number concentration in the size range 10-650 nm could be varied from <10 cm(-3) to more than 900,000 cm(-3) (for candle smoke) or to more than 30,000 cm(-3) (for particles formed in a 160 ppb terpene/40 ppb ozone mixture). Furthermore, the set-ups were evaluated by, for each source, repeating the generation at six three-hour long events. For both aerosols repeatable generations at pre-determined concentration levels, that were stable over time, could be achieved. The results show that realistic concentrations of aerosols from real-world environments could be reproduced in a well-controlled manner and that this set-up could be used both for aerosol characterization and for human exposures. (C) 2013 Elsevier Ltd. All rights reserved.
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- Ljungqvist, Göran, et al.
(författare)
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Biomarker for welding exposure in exhaled endogenous particles
- 2014
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Ingår i: The European respiratory journal. Supplement. - 0904-1850.
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Konferensbidrag (refereegranskat)abstract
- More than two million workers are exposed to pneumotoxic welding aerosols and there is a need for target organ specific biomarkers of exposure. Manganese is a common constituent of iron alloys, its occupational exposure limit is low and other biomarkers are poor, which makes it a good model substance. We hypothesize that metal particles are deposited in the small airways and are incorporated into endogenous particles formed during respiration. A subsequent analysis of these particles in exhaled air (PEx) can serve as a biomarker for metals in welding fumes. We have recently developed a method for the collection of PEx (Almstrand, A.-C. et al. Anal Chem 2008; 81:662-668), based on counting of the exhaled particles and subsequent collection by impaction on a filter. Here we developed a method for analysis of trace metal content, i.e. manganese and iron in PEx. The method involved desorption of the filter in 5% nitric acid and analysis of the metal content by ICP-MS. To test our hypothesis, we exposed 9 healthy non-smokers (4F/5M, 29-63 years) to welding aerosol in an exposure chamber (Isaxon, C. et al. Aerosol Sci Tech 2012; 47:52-59) for two hours. Manganese and iron was analysed in PEx samples collected before, immediately after and 24 h after exposure. The results showed that 4 out of 9 persons had substantially increased levels of both manganese and iron in PEx immediately after exposure. Before exposure two samples had an iron content above limit of detection and none of the samples collected after 24 h. Manganese was below LOD in all samples collected before and 24 h after exposure. The study showed that the analysis of metals in PEx is a promising biomarker for metal aerosol exposure.
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| 32. |
- Morawska, L., et al.
(författare)
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Indoor aerosols: from personal exposure to risk assessment
- 2013
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Ingår i: Indoor Air. - : Hindawi Limited. - 0905-6947. ; 23:6, s. 462-487
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Forskningsöversikt (refereegranskat)abstract
- Motivated by growing considerations of the scale, severity, and risks associated with human exposure to indoor particulate matter, this work reviewed existing literature to: (i) identify state-of-the-art experimental techniques used for personal exposure assessment; (ii) compare exposure levels reported for domestic/school settings in different countries (excluding exposure to environmental tobacco smoke and particulate matter from biomass cooking in developing countries); (iii) assess the contribution of outdoor background vs indoor sources to personal exposure; and (iv) examine scientific understanding of the risks posed by personal exposure to indoor aerosols. Limited studies assessing integrated daily residential exposure to just one particle size fraction, ultrafine particles, show that the contribution of indoor sources ranged from 19% to 76%. This indicates a strong dependence on resident activities, source events and site specificity, and highlights the importance of indoor sources for total personal exposure. Further, it was assessed that 10-30% of the total burden of disease from particulate matter exposure was due to indoor-generated particles, signifying that indoor environments are likely to be a dominant environmental factor affecting human health. However, due to challenges associated with conducting epidemiological assessments, the role of indoor-generated particles has not been fully acknowledged, and improved exposure/risk assessment methods are still needed, together with a serious focus on exposure control.
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| 38. |
- Nilsson, Patrik, et al.
(författare)
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Nano-objects emitted during maintenance of common particle generators: direct chemical characterization with aerosol mass spectrometry and implications for risk assessments
- 2013
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Ingår i: Journal of Nanoparticle Research. - : Springer Science and Business Media LLC. - 1572-896X .- 1388-0764. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Nanotechnology gives us materials with enhanced or completely new properties. At the same time, inhalation of manufactured nano-objects has been related to an array of adverse biological effects. We characterized particle emissions, which occurred during maintenance of common metal nanoparticle generators and contrasted the properties of the emitted particles with those originally produced by the generators. A new approach using online aerosol mass spectrometry (AMS), for time-and size-resolved measurements of the particle chemical composition, was applied in combination with more conventional techniques for particle sampling and analysis, including electron microscopy. Emissions during maintenance work, in terms of mass and surface area concentration in the size range of 0.02-10 mu m, were dominated by large agglomerates (1-5 mu m). With AMS, we show that the particle composition depends on both generator type and maintenance task being performed and that the instrument can be used for highly time-resolved selective studies of metal nanoparticle emissions. The emitted agglomerates have a relatively high probability to be deposited in the lower respiratory tract, since the mean particle diameter coincided with a peak in the lung deposition curve. Each of these agglomerates consisted of a very high number (10(3)-10(5)/agglomerate) of nanometer-sized primary particles originating from the particle synthesis process. This made them possess large surface areas, one of the key properties in nanotoxicology. Similar agglomerates may be emitted in a wide range of processes when nanoparticles are manufactured or handled. The fate of such agglomerates, once deposited in the respiratory tract, is unknown and should therefore be considered in future particle toxicological studies. Our results highlight the importance of including micrometer-sized particles in exposure and emission assessments.
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