| 1. |
- Lovén, Karin, et al.
(författare)
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Toxicological effects of zinc oxide nanoparticle exposure : an in vitro comparison between dry aerosol air-liquid interface and submerged exposure systems
- 2021
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Ingår i: Nanotoxicology. - : Taylor and Francis Ltd.. - 1743-5390 .- 1743-5404. ; 15:4, s. 494-510
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Tidskriftsartikel (refereegranskat)abstract
- Engineered nanomaterials (ENMs) are increasingly produced and used today, but health risks due to their occupational airborne exposure are incompletely understood. Traditionally, nanoparticle (NP) toxicity is tested by introducing NPs to cells through suspension in the growth media, but this does not mimic respiratory exposures. Different methods to introduce aerosolized NPs to cells cultured at the air-liquid-interface (ALI) have been developed, but require specialized equipment and are associated with higher cost and time. Therefore, it is important to determine whether aerosolized setups induce different cellular responses to NPs than traditional ones, which could provide new insights into toxicological responses of NP exposure. This study evaluates the response of human alveolar epithelial cells (A549) to zinc oxide (ZnO) NPs after dry aerosol exposure in the Nano Aerosol Chamber for In Vitro Toxicity (NACIVT) system as compared to conventional, suspension-based exposure: cells at ALI or submerged. Similar to other studies using nebulization of ZnO NPs, we found that dry aerosol exposure of ZnO NPs via the NACIVT system induced different cellular responses as compared to conventional methods. ZnO NPs delivered at 1.0 µg/cm2 in the NACIVT system, mimicking occupational exposure, induced significant increases in metabolic activity and release of the cytokines IL-8 and MCP-1, but no differences were observed using traditional exposures. While factors associated with the method of exposure, such as differing NP aggregation, may contribute toward the different cellular responses observed, our results further encourage the use of more physiologically realistic exposure systems for evaluating airborne ENM toxicity. © 2021 The Author(s).
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| 2. |
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| 3. |
- Muala, Ala, et al.
(författare)
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Respiratory Tract Deposition of Inhaled Wood Smoke Particles in Healthy Volunteers
- 2015
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Ingår i: Journal of Aerosol Medicine. - : Mary Ann Liebert Inc. - 1941-2711 .- 1941-2703. ; 28:4, s. 237-246
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Tidskriftsartikel (refereegranskat)abstract
- Background: Respiratory tract deposition of air pollution particles is a key to their adverse health effects. This study was aimed to determine the size-resolved deposition fraction (DF) of sooty wood smoke particles in the lungs of healthy subjects. The type of wood smoke investigated is typical for household air pollution from solid fuels, which is among the largest environmental health problems globally.Methods: Twelve healthy volunteers inhaled diluted wood smoke from incomplete soot-rich combustion in a common wood stove. The DF of smoke particles (10–500 nm) was measured during three 15-min exposures in each subject during spontaneous breathing. Lung function was measured using standard spirometry.Results: The total DFs by particle number concentration were 0.34±0.08. This can be compared with DFs of 0.21–0.23 in healthy subjects during previous experiments with wood pellet combustion. For particle mass, the total DFs found in this study were 0.22±0.06. DF and breathing frequency were negatively correlated as expected from model calculations (p<0.01).Conclusions: The DF of the investigated sooty wood smoke particles was higher than for previously investigated particles generated during more efficient combustion of biomass. Together with toxicological studies, which have indicated that incomplete biomass combustion particles rich in soot and polycyclic aromatic hydrocarbons (PAHs) are especially harmful, these data highlight the health risks of inadequate wood combustion.
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| 4. |
- Abrahamsson, Camilla, et al.
(författare)
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Aerosolized particulate matter from fragmentation of carbon nanotube-enhanced concrete
- 2023
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Ingår i: Abstracts from the 2022 Airmon-10 conference and the 2023 Inhaled Particles and NanOEH conference. - 2398-7316 .- 2398-7308. ; 67:Supplement_1, s. i94-i95
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Konferensbidrag (refereegranskat)abstract
- Construction and demolition workers are exposed to high levels of particulate matter (PM) from building materials throughout their working life. Although nano-enabled building materials (NEBMs) may improve the performance and functionality of buildings, concerns are being raised regarding health risks from occupational exposure to PM from NEBMs. In this work, an experimental set-up for integrated resuspension and characterization of PM from NEBMs was developed and tested using three types of concrete (low density, normal, high strength), each enhanced with Carbon Nanotubes (CNTs) at different concentrations (0, low, high). The performance of portable devices used in occupational exposure assessments (DustTrak and NanoTracer) was compared with stationary instruments and gravimetric filter techniques. 40-70% of the mass and 90-98% of the number of particles were within the respirable fraction, with primary modes at 150 nm and 2-3 µm. Addition of CNTs significantly decreased mean particle number concentrations (PNCs) across the entire characterized size range (7 nm - 20 µm) for low density concrete, whereas the opposite was the case for normal strength and high strength concrete. It was hypothesised that the concrete matrix primarily governs the PM formation, which is in turn modulated by CNT-matrix interactions either suppressing or supporting fragmentation during crushing. SEM imaging could display partially submerged CNTs protruding from concrete fragments. Fundamental interactions at the interface of the nanomaterial and the surrounding matrix needs to be investigated to determine how the PM generated from NEBMs differ from their non-nano counterparts and how to prevent future exposure during demolition.
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| 5. |
- Abrahamsson, Camilla, et al.
(författare)
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Characterization of airborne dust emissions from three types of crushed multi-walled carbon nanotube-enhanced concretes
- 2024
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Ingår i: NanoImpact. - : Elsevier B.V.. - 2452-0748. ; 34
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Tidskriftsartikel (refereegranskat)abstract
- Dispersing Multi-Walled Carbon Nanotubes (MWCNTs) into concrete at low (<1 wt% in cement) concentrations may improve concrete performance and properties and provide enhanced functionalities. When MWCNT-enhanced concrete is fragmented during remodelling or demolition, the stiff, fibrous and carcinogenic MWCNTs will, however, also be part of the respirable particulate matter released in the process. Consequently, systematic aerosolizing of crushed MWCNT-enhanced concretes in a controlled environment and measuring the properties of this aerosol can give valuable insights into the characteristics of the emissions such as concentrations, size range and morphology. These properties impact to which extent the emissions can be inhaled as well as where they are expected to deposit in the lung, which is critical to assess whether these materials might constitute a future health risk for construction and demolition workers. In this work, the impact from MWCNTs on aerosol characteristics was assessed for samples of three concrete types with various amounts of MWCNT, using a novel methodology based on the continuous drop method. MWCNT-enhanced concretes were crushed, aerosolized and the emitted particles were characterized with online and offline techniques. For light-weight porous concrete, the addition of MWCNT significantly reduced the respirable mass fraction (RESP) and particle number concentrations (PNC) across all size ranges (7 nm – 20 μm), indicating that MWCNTs dampened the fragmentation process by possibly reinforcing the microstructure of brittle concrete. For normal concrete, the opposite could be seen, where MWCNTs resulted in drastic increases in RESP and PNC, suggesting that the MWCNTs may be acting as defects in the concrete matrix, thus enhancing the fragmentation process. For the high strength concrete, the fragmentation decreased at the lowest MWCNT concentration, but increased again for the highest MWCNT concentration. All tested concrete types emitted <100 nm particles, regardless of CNT content. SEM imaging displayed CNTs protruding from concrete fragments, but no free fibres were detected.
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| 6. |
- Al-Rekabi, Zeinab, et al.
(författare)
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Uncovering the cytotoxic effects of air pollution with multi-modal imaging of in vitro respiratory models
- 2023
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Ingår i: Royal Society Open Science. - : Royal Society Publishing. - 2054-5703. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- Annually, an estimated seven million deaths are linked to exposure to airborne pollutants. Despite extensive epidemiological evidence supporting clear associations between poor air quality and a range of short- and long-term health effects, there are considerable gaps in our understanding of the specific mechanisms by which pollutant exposure induces adverse biological responses at the cellular and tissue levels. The development of more complex, predictive, in vitro respiratory models, including two- and three-dimensional cell cultures, spheroids, organoids and tissue cultures, along with more realistic aerosol exposure systems, offers new opportunities to investigate the cytotoxic effects of airborne particulates under controlled laboratory conditions. Parallel advances in high-resolution microscopy have resulted in a range of in vitro imaging tools capable of visualizing and analysing biological systems across unprecedented scales of length, time and complexity. This article considers state-of-the-art in vitro respiratory models and aerosol exposure systems and how they can be interrogated using high-resolution microscopy techniques to investigate cell-pollutant interactions, from the uptake and trafficking of particles to structural and functional modification of subcellular organelles and cells. These data can provide a mechanistic basis from which to advance our understanding of the health effects of airborne particulate pollution and develop improved mitigation measures.
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| 7. |
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| 8. |
- Ali, Neserin, et al.
(författare)
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Analysis of nanoparticle-protein coronas formed in vitro between nanosized welding particles and nasal lavage proteins.
- 2016
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Ingår i: Nanotoxicology. - : Taylor & Francis. - 1743-5390 .- 1743-5404. ; 10:2, s. 226-234
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Tidskriftsartikel (refereegranskat)abstract
- Welding fumes include agglomerated particles built up of primary nanoparticles. Particles inhaled through the nose will to some extent be deposited in the protein-rich nasal mucosa, and a protein corona will be formed around the particles. The aim was to identify the protein corona formed between nasal lavage proteins and four types of particles with different parameters. Two of the particles were formed and collected during welding and two were manufactured iron oxides. When nasal lavage proteins were added to the particles, differences were observed in the sizes of the aggregates that were formed. Measurements showed that the amount of protein bound to particles correlated with the relative size increase of the aggregates, suggesting that the surface area was associated with the binding capacity. However, differences in aggregate sizes were detected when nasal proteins were added to UFWF and Fe2O3 particles (having similar agglomerated size) suggesting that yet parameters other than size determine the binding. Relative quantitative mass spectrometric and gel-based analyses showed differences in the protein content of the coronas. High-affinity proteins were further assessed for network interactions. Additional experiments showed that the inhibitory function of secretory leukocyte peptidase inhibitor, a highly abundant nasal protein, was influenced by particle binding suggesting that an understanding of protein function following particle binding is necessary to properly evaluate pathophysiological events. Our results underscore the importance of including particles collected from real working environments when studying the toxic effects of particles because these effects might be mediated by the protein corona.
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| 9. |
- Ali, Neserin, et al.
(författare)
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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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Ingår i: Clinical Proteomics. - : Springer Science and Business Media LLC. - 1542-6416 .- 1559-0275. ; 15:1
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Tidskriftsartikel (refereegranskat)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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| 10. |
- Bergman, Fanny, et al.
(författare)
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Physicochemical metamorphosis of re-aerosolized urban PM2.5
- 2024
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Ingår i: Journal of Aerosol Science. - : Elsevier Ltd. - 0021-8502 .- 1879-1964. ; 181
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Tidskriftsartikel (refereegranskat)abstract
- The toxicity of particulate matter (PM) is dependent on particle physical and chemical properties and is commonly studied using in vivo and in vitro approaches. PM to be used for in vivo and in vitro studies is often collected on filters and then extracted from the filter surface using a solvent. During extraction and further PM sample handling, particle properties change, but this is often neglected in toxicology studies, with possible implications for health effect assessment. To address the current lack of knowledge and investigate changes in particle properties further, ambient PM with diameter less than 2.5 μm (PM2.5) was collected on filters at an urban site and extracted using a standard methanol protocol. After extraction, the PM was dried, dispersed in water and subsequently nebulized. The resulting aerosol properties were then compared to those of the ambient PM2.5. The number size distribution for the nebulized aerosol resembled the ambient in terms of the main mode diameter, and >90 % of particle mass in the nebulized size distribution was still in the PM2.5 range. Black carbon made up a similar fraction of PM mass in nebulized as in ambient aerosol. The sulfate content in the nebulized aerosol seemed depleted and the chemical composition of the organic fraction was altered, but it remains unclear to what extent other non-refractory components were affected by the extraction process. Trace elements were not distributed equally across size fractions, neither in ambient nor nebulized PM. Change in chemical form was studied for zinc, copper and iron. The form did not appear to be different between the ambient and nebulized PM for iron and copper, but seemed altered for zinc. Although many of the studied properties were reasonably well preserved, it is clear that the PM2.5 collection and re-aerosolization process affects particles, and thus potentially also their health effects. Because of this, the effect of the particle collection and extraction process must be considered when evaluating cellular and physiological outcomes upon PM2.5 exposure. © 2024 The Authors
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| 11. |
- Bergman, Fanny, et al.
(författare)
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Physicochemical metamorphosis of re-aerosolized urban PM2.5
- 2024
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Ingår i: Journal of Aerosol Science. - : Elsevier Ltd. - 0021-8502 .- 1879-1964. ; 181
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Tidskriftsartikel (refereegranskat)abstract
- The toxicity of particulate matter (PM) is dependent on particle physical and chemical properties and is commonly studied using in vivo and in vitro approaches. PM to be used for in vivo and in vitro studies is often collected on filters and then extracted from the filter surface using a solvent. During extraction and further PM sample handling, particle properties change, but this is often neglected in toxicology studies, with possible implications for health effect assessment. To address the current lack of knowledge and investigate changes in particle properties further, ambient PM with diameter less than 2.5 μm (PM2.5) was collected on filters at an urban site and extracted using a standard methanol protocol. After extraction, the PM was dried, dispersed in water and subsequently nebulized. The resulting aerosol properties were then compared to those of the ambient PM2.5. The number size distribution for the nebulized aerosol resembled the ambient in terms of the main mode diameter, and >90 % of particle mass in the nebulized size distribution was still in the PM2.5 range. Black carbon made up a similar fraction of PM mass in nebulized as in ambient aerosol. The sulfate content in the nebulized aerosol seemed depleted and the chemical composition of the organic fraction was altered, but it remains unclear to what extent other non-refractory components were affected by the extraction process. Trace elements were not distributed equally across size fractions, neither in ambient nor nebulized PM. Change in chemical form was studied for zinc, copper and iron. The form did not appear to be different between the ambient and nebulized PM for iron and copper, but seemed altered for zinc. Although many of the studied properties were reasonably well preserved, it is clear that the PM2.5 collection and re-aerosolization process affects particles, and thus potentially also their health effects. Because of this, the effect of the particle collection and extraction process must be considered when evaluating cellular and physiological outcomes upon PM2.5 exposure.
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| 12. |
- Bladh, Henrik, et al.
(författare)
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Influence of Soot Particle Aggregation on Time-Resolved Laser-Induced Incandescence Signals
- 2011
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Ingår i: Applied Physics B. - : Springer Science and Business Media LLC. - 0946-2171 .- 1432-0649. ; 104:2, s. 331-341
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Tidskriftsartikel (refereegranskat)abstract
- Laser-induced incandescence (LII) is a versatile technique for quantitative soot measurements in flames and exhausts. When used for particle sizing, the time-resolved signals are analysed as these will show a decay rate dependent on the soot particle size. Such an analysis has traditionally been based on the assumption of isolated primary particles. However, soot particles in flames and exhausts are usually aggregated, which implies loss of surface area, less heat conduction and hence errors in estimated particle sizes. In this work we present an experimental investigation aiming to quantify this effect. A soot generator, based on a propane diffusion flame, was used to produce a stable soot stream and the soot was characterised by transmission electron microscopy (TEM), a scanning mobility particle sizer (SMPS) and an aerosol particle mass analyzer coupled in series after a differential mobility analyzer (DMA-APM). Despite nearly identical primary particle size distributions for three selected operating conditions, LII measurements resulted in signal decays with significant differences in decay rate. However, the three cases were found to have quite different levels of aggregation as shown both in TEM images and mobility size distributions, and the results agree qualitatively with the expected effect of diminished heat conduction from aggregated particles resulting in longer LII signal decays. In an attempt to explain the differences quantitatively, the LII signal dependence on aggregation was modelled using a heat and mass transfer model for LII given the primary particle and aggregate size distribution data as input. Quantitative agreement was not reached and reasons for this discrepancy are discussed.
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| 13. |
- Blomberg, Sara, et al.
(författare)
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Bimetallic nanoparticles as a model system for an industrial NiMo catalyst
- 2019
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 12:22
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Tidskriftsartikel (refereegranskat)abstract
- An in-depth understanding of the reactionmechanismis required for the further development of Mo-based catalysts for biobased feedstocks. However, fundamental studies of industrial catalysts are challenging, and simplified systems are often used without direct comparison to their industrial counterparts. Here, we report on size-selected bimetallic NiMo nanoparticles as a candidate for a model catalyst that is directly compared to the industrial system to evaluate their industrial relevance. Both the nanoparticles and industrial supported NiMo catalysts were characterized using surface- and bulk-sensitive techniques. We found that the active Ni and Mo metals in the industrial catalyst are well dispersed and well mixed on the support, and that the interaction between Ni and Mo promotes the reduction of the Mo oxide. We successfully produced 25 nm NiMo alloyed nanoparticles with a narrow size distribution. Characterization of the nanoparticles showed that they have a metallic core with a native oxide shell with a high potential for use as a model system for fundamental studies of hydrotreating catalysts for biobased feedstocks. © 2019 by the authors.
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| 14. |
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| 15. |
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| 16. |
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| 17. |
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| 18. |
- Dahl, Jonas, et al.
(författare)
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Avancerad spektroskopisk speciering av metaller i askan från avfallsförbränning
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Användning av sekundära råvaror har på senare tid fått ett ökat fokus med den drivkraft som finns kring cirkulär omställning. Möjligheten att nyttja askor ifrån avfallsförbränning är starkt beroende av deras innehåll av toxiska men också värdefulla komponenter, bland annat metaller.Föreliggande projekt har undersökt möjligheterna med att använda röntgenabsorptionsspektroskopi (XAS) för att påvisa de dominerande förekomstformerna av metallerna zink, bly, koppar och antimon i askor från förbränning av avfall. En ökad kunskap om dessa förekomstformer kan ge nya möjligheter till klassificering av bottenaskor (slaggrus) samt ge viktig information för optimering av behandlingsmetoder för att endera stabilisera flygaskor för säker deponi eller för utvinning av värdefulla metaller. I projektet ingick därför analyser av ett mindre antal askor representerande både färska och lagrade bottenaskor samt behandlade och icke behandlade flygaskor. Dessutom representerades olika förbränningsteknologier, såsom rosterpanna, roterugn och cirkulerande fluidiserad bädd (CFB).I projektet har röntgen-absorptionsspektroskopimätningar (XAS) genomförts vid BALDER som är ett av strålrören på MAX IV laboratoriet, Lund. XAS kan delas in i två delar, EXAFS och XANES, där XANES utnyttjar den första delen av spektrumet (energier närmast absorptionskanten) och kräver betydligt kortare analystid än en full EXAFS analys (högre energier). Fokus har därför legat på XANES i detta projekt då det är den teknik som har störst potential att fungera som en tidseffektiv standardanalys på MAX IV, speciellt för heterogena prov som genererar hög brusnivå vilket är typiskt för askor.Metoden är väldigt beroende av relevanta referensspektrum för att kunna identifiera de olika förekomstformerna. En stor del av arbetet har därför varit att identifiera, framskaffa, kontrollera renhetsgrad för och slutligen mäta på de totalt 43 referensmaterial som använts i analyserna (14 zinkföreningar, 14 kopparföreningar, 10 blyföreningar och 3 antimonföreningar). Dessa spektrum ligger kvar i en databas på MAX IV och kan därför utökas och kompletteras med nya relevanta referensmaterial för att ytterligare förbättra metoden framöver. Dessa är också tillgängliga för andra användare av MAX IV.Resultaten visade inte oväntat på att bottenaskor är mer heterogena än flygaskor vilket gav mer brus i analyserna av dessa askor, men med god reproducerbarhet. Övriga trender är beroende på vilket grundämne som undersöks.Den klart vanligaste förekomstformer av zink är silikatet hemimorfit (Zn4Si2O7(OH)2·H2O) både i flyg- och bottenaskor. Analyserna föreslår att ca. 20-40 % av zink återfinns i denna form i de flesta askorna. Övriga dominerande förekomstformer sett till andelen zink är Zn5(CO3)2(OH)6 (Hydrozinkit) och ett annat silkat som heter Willemite och har formeln Zn2SiO3 men med en större skillnad mellan de olika analyserade askorna. En viss andel zinkklorid, ZnCl2, återfinns också i de flesta askorna.Den vanligaste förekomstformen av koppar i flygaskor är Cu(OH)2 (30–55%) men resultaten för bottenaskorna visar på en mer komplex sammansättning med olika oxidformer (CuO, Cu2O, CuFe2O4, Cu2SiO3) men också på förekomst av karbonat (CuCO3*Cu(OH)2) i ett av de lagrade proven.Den vanligaste förekomstformen av bly är associerad med någon form av silikat (PbSiO3 eller bundet till amorft SiO2 – liknande strukturen i Pb-glas), men även PbCl2 är vanligt förekommande, speciellt i flygaskor.Antimon var bara delvis inkluderad i studien och begränsat till tre referenser. Analysen fokuserade därför på att detektera skillnader före och efter behandling av flygaska. Ingen sådan skillnad kunde detekteras. Värt att notera är att Sb-spektrumet för den bottenaska som analyserades är identisk med det för referensen Sb2O5 och att oxidationstalet för Sb i alla askor ligger nära den för samma referens.En slutsats av analyserna var att vissa av referensmaterialens spektrum är mycket lika vilket resulterar i att några referenser som t.ex. ZnS aktivt behövdes selekteras bort vid analyserna baserat på kunskap om hur trolig deras förekomst i askorna är. Det finns också starka indikationer på att fler referensmaterial behövs för att beskriva några av askorna. En kombination av andra mätmetoder som t.ex. μ-XRF föreslås därför som en möjlighet i framtida arbete för att identifiera viktiga saknade referensmaterial. Dessutom skulle en jämförelse med lakanalyser vara kunskapsbyggande.Sammanfattningsvis har det i projektet utvecklats en fungerande analysmetod som har potential att kunna bli industriellt gångbar. De resultat som tagits fram kring möjliga förekomstformer är, sett till vad som finns publicerat i litteraturen, betydande. Men för att dra riktiga slutsatser kring olika påverkansfaktorer krävs betydligt fler riktade analyser.
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| 19. |
- Dobric, Julia, et al.
(författare)
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Physical activity changes the deposited fractions of particles in the respiratory tract of adults and children
- 2022
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Ingår i: ; , s. 45-45
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Konferensbidrag (refereegranskat)abstract
- Exposure to ambient air pollution can cause a numberof health problems and may be particularly dangerous to susceptible population groups such as children. Health effects caused by air pollution are criticallydependent on both the deposited fraction (DF) of the inhaled particles and in what region of the respiratory tract the deposition takes place. With increasing physical activity, the breathing pattern is altered and the airflow in the respiratory tract increase, this affects the DF and deposition site. In this study we investigated changes in DF at increasing physical activity for three population groups: ~5 and 10 year-old children, and adults.Our results indicate that the variation in total DF with physical activity is minor, but that the DF for the UFPs increase in the AI region at higher activity levels. This is important since the removal of particles in the AI region is not effective and UFPs are believed to pose a specific health risk. Therefore, activity patterns and DF of different population groups need to be considered when estimating particle dose and evaluating health risks.
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| 20. |
- Dobric, Julia, et al.
(författare)
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Preschool Children’s Inhalation Rates Estimated from Accelerometers—A Tool to Estimate Children’s Exposure to Air Pollution
- 2022
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Ingår i: Aerosol and Air Quality Research. - : AAGR Aerosol and Air Quality Research. - 1680-8584 .- 2071-1409. ; 22:8
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Tidskriftsartikel (refereegranskat)abstract
- Children are particularly sensitive to air pollution exposure, and their personal exposures may differ significantly from those of adults. One key factor for understanding the personal inhaled dose of air pollutants is the respiratory minute ventilation (Ve). To estimate the amount of particles circulated through the lungs, 24 h averages of Ve are often used. These averages poorly capture variations in Ve during the day, and between individuals. We here develop and implement a concept to assess individual Ve of children, with minimal impact on their natural activity and movement pattern by using ActiGraph GT3X+ accelerometers. Activity of 136 preschool children in the ages 3 to 5 years was logged using accelerometers while the children attended their preschools during a week. A linear regression equation is developed and used for estimating Ve from the accelerometer data retrieved for each individual child. The results show large variations in weekly average Ve between individuals, ranging from 0.33 to 0.48 L min–1 kg–1. Over the days the averages of the individuals’ 1st and 3rd quartiles were 0.28 and 0.48 L min–1 kg–1, respectively. Outdoor activities resulted in a 17% higher Ve than indoor activities, which may be important to consider when estimating the inhaled dose of air pollutants since pollution levels and particle toxicities can be different indoors and outdoors. The observations motivate the use of individual values of Ve in exposure assessments and suggest that accelerometers are a suitable tool for estimating children’s individual Ve in their natural environment. Combined with time resolved local air pollution monitoring, these measurements can provide the basis of a more precise estimate of children’s inhaled dose of air pollutants. © The Author(s).
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| 21. |
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| 22. |
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| 23. |
- Eriksson, Axel, et al.
(författare)
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Diesel soot aging in urban plumes within hours under cold dark and humid conditions
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322.
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Tidskriftsartikel (refereegranskat)abstract
- Fresh and aged diesel soot particles have different impacts on climate and human health. While fresh diesel soot particles are highly aspherical and non-hygroscopic, aged particles are spherical and hygroscopic. Aging and its effect on water uptake also controls the dispersion of diesel soot in the atmosphere. Understanding the timescales on which diesel soot ages in the atmosphere is thus important, yet knowledge thereof is lacking. We show that under cold, dark and humid conditions the atmospheric transformation from fresh to aged soot occurs on a timescale of less than five hours. Under dry conditions in the laboratory, diesel soot transformation is much less efficient. While photochemistry drives soot aging, our data show it is not always a limiting factor. Field observations together with aerosol process model simulations show that the rapid ambient diesel soot aging in urban plumes is caused by coupled ammonium nitrate formation and water uptake.
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| 25. |
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