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- Bilde, M., et al.
(författare)
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Saturation Vapor Pressures and Transition Enthalpies of Low-Volatility Organic Molecules of Atmospheric Relevance: From Dicarboxylic Acids to Complex Mixtures
- 2015
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Ingår i: Chemical Reviews. - : American Chemical Society (ACS). - 0009-2665 .- 1520-6890. ; 115:10, s. 4115-4156
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Forskningsöversikt (refereegranskat)abstract
- There are a number of techniques that can be used that differ in terms of whether they fundamentally probe the equilibrium and the temperature range over which they can be applied. The series of homologous, straight-chain dicarboxylic acids have received much attention over the past decade given their atmospheric relevance, commercial availability, and low saturation vapor pressures, thus making them ideal test compounds. Uncertainties in the solid-state saturation vapor pressures obtained from individual methodologies are typically on the order of 50-100%, but the differences between saturation vapor pressures obtained with different methods are approximately 1-4 orders of magnitude, with the spread tending to increase as the saturation vapor pressure decreases. Some of the dicarboxylic acids can exist with multiple solid-state structures that have distinct saturation vapor pressures. Furthermore, the samples on which measurements are performed may actually exist as amorphous subcooled liquids rather than solid crystalline compounds, again with consequences for the measured saturation vapor pressures, since the subcooled liquid phase will have a higher saturation vapor pressure than the crystalline solid phase. Compounds with equilibrium vapor pressures in this range will exhibit the greatest sensitivities in terms of their gas to particle partitioning to uncertainties in their saturation vapor pressures, with consequent impacts on the ability of explicit and semiexplicit chemical models to simulate secondary organic aerosol formation.
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- Ahlberg, Erik, et al.
(författare)
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"Vi klimatforskare stödjer Greta och skolungdomarna"
- 2019
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Ingår i: Dagens nyheter (DN debatt). - 1101-2447.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- DN DEBATT 15/3. Sedan industrialiseringens början har vi använt omkring fyra femtedelar av den mängd fossilt kol som får förbrännas för att vi ska klara Parisavtalet. Vi har bara en femtedel kvar och det är bråttom att kraftigt reducera utsläppen. Det har Greta Thunberg och de strejkande ungdomarna förstått. Därför stödjer vi deras krav, skriver 270 klimatforskare.
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- 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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- Andersen, Christina, et al.
(författare)
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Emissions of soot, PAHs, ultrafine particles, NOx, and other health relevant compounds from stressed burning of candles in indoor air
- 2021
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Ingår i: Indoor Air. - : Hindawi Limited. - 0905-6947 .- 1600-0668. ; 31:6, s. 2033-2048
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Tidskriftsartikel (refereegranskat)abstract
- Burning candles release a variety of pollutants to indoor air, some of which are of concern for human health. We studied emissions of particles and gases from the stressed burning of five types of pillar candles with different wax and wick compositions. The stressed burning was introduced by controlled fluctuating air velocities in a 21.6 m3 laboratory chamber. The aerosol physicochemical properties were measured both in well-mixed chamber air and directly above the candle flame with online and offline techniques. All candles showed different emission profiles over time with high repeatability among replicates. The particle mass emissions from stressed burning for all candle types were dominated by soot (black carbon; BC). The wax and wick composition strongly influenced emissions of BC, PM2.5 , and particle-phase polycyclic aromatic hydrocarbons (PAHs), and to lower degree ultrafine particles, inorganic and organic carbon fraction of PM, but did not influence NOx , formaldehyde, and gas-phase PAHs. Measurements directly above the flame showed empirical evidence of short-lived strong emission peaks of soot particles. The results show the importance of including the entire burn time of candles in exposure assessments, as their emissions can vary strongly over time. Preventing stressed burning of candles can reduce exposure to pollutants in indoor air.
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- Andersen, Christina, et al.
(författare)
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Inhalation and dermal uptake of particle and gas phase phthalates - A human chamber exposure study
- 2018
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Ingår i: 15th Conference of the International Society of Indoor Air Quality and Climate, INDOOR AIR 2018. - 9781713826514
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Konferensbidrag (refereegranskat)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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- Andersen, Christina, et al.
(författare)
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Inhalation and Dermal Uptake of Particle and Gas-phase Phthalates - A Human Exposure Study
- 2018
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Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 1520-5851 .- 0013-936X. ; 52:21, s. 12792-12800
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Tidskriftsartikel (refereegranskat)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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- Arinaitwe, Evalyne, et al.
(författare)
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Firefighter’s exposures : Preliminary study on fire gases from burning ‘new’ and sustainable building materials
- 2024
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Ingår i: ; , s. 93-94
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Konferensbidrag (refereegranskat)abstract
- Firefighters are exposed to harmful and toxic substances during firefighting activities (i.e. training, live firefighting and overhaul) in building fires. This paper studies the impact of ‘new’ and sustainable materials (‘green’ buildings) on firefighter’s exposures during firefighting interventions. Cross-laminated wood (CLT), recycled wood material (referred to as ‘RECOMA’ in this paper) and glass fiberreinforced polymer (FRP) were burned in the cone calorimeter and the gasses produced quantified using Fourier Transform Infrared (FTIR) spectroscopy. Results show that many different fire gases are produced beyond the common gas analysis of oxygen, carbon monoxide and carbon dioxide by standard fire testing equipment. The presence of benzene and formaldehyde which are associated with increased risk for cancers in humans, indicates the need for better understanding of fire gases from such new materials in order to continually ensure the proper protection of firefighters.
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- Bendtsen, Katja Maria, et al.
(författare)
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Particle characterization and toxicity in C57BL/6 mice following instillation of five different diesel exhaust particles designed to differ in physicochemical properties
- 2020
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Ingår i: Particle and Fibre Toxicology. - : Springer Science and Business Media LLC. - 1743-8977. ; 17:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Diesel exhaust is carcinogenic and exposure to diesel particles cause health effects. We investigated the toxicity of diesel exhaust particles designed to have varying physicochemical properties in order to attribute health effects to specific particle characteristics. Particles from three fuel types were compared at 13% engine intake O2 concentration: MK1 ultra low sulfur diesel (DEP13) and the two renewable diesel fuels hydrotreated vegetable oil (HVO13) and rapeseed methyl ester (RME13). Additionally, diesel particles from MK1 ultra low sulfur diesel were generated at 9.7% (DEP9.7) and 17% (DEP17) intake O2 concentration. We evaluated physicochemical properties and histopathological, inflammatory and genotoxic responses on day 1, 28, and 90 after single intratracheal instillation in mice compared to reference diesel particles and carbon black. RESULTS: Moderate variations were seen in physical properties for the five particles: primary particle diameter: 15-22 nm, specific surface area: 152-222 m2/g, and count median mobility diameter: 55-103 nm. Larger differences were found in chemical composition: organic carbon/total carbon ratio (0.12-0.60), polycyclic aromatic hydrocarbon content (1-27 μg/mg) and acid-extractable metal content (0.9-16 μg/mg). Intratracheal exposure to all five particles induced similar toxicological responses, with different potency. Lung particle retention was observed in DEP13 and HVO13 exposed mice on day 28 post-exposure, with less retention for the other fuel types. RME exposure induced limited response whereas the remaining particles induced dose-dependent inflammation and acute phase response on day 1. DEP13 induced acute phase response on day 28 and inflammation on day 90. DNA strand break levels were not increased as compared to vehicle, but were increased in lung and liver compared to blank filter extraction control. Neutrophil influx on day 1 correlated best with estimated deposited surface area, but also with elemental carbon, organic carbon and PAHs. DNA strand break levels in lung on day 28 and in liver on day 90 correlated with acellular particle-induced ROS. CONCLUSIONS: We studied diesel exhaust particles designed to differ in physicochemical properties. Our study highlights specific surface area, elemental carbon content, PAHs and ROS-generating potential as physicochemical predictors of diesel particle toxicity.
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- 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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- Bohgard, Mats, et al.
(författare)
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Pedagogisk förändring av arbetsvetenskapskurser i några olika utbildningsprogram vid LTH
- 2003
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Ingår i: Pedagogisk inspirationskonferens LTH 27 maj 2003. - Lund : Lunds tekniska högskola, Lunds universitet. ; , s. 14-17
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Konferensbidrag (refereegranskat)abstract
- Vi har genomfört genomgripande förändringar i obligatoriska grundkurser i arbetsvetenskap. Förändringarna har genomförts som en utvecklingsprocess i vilken samtliga lärare som deltagit i kurserna har medverkat. Processen startade med konsulthjälp från Universitetspedagogiskt centrum vid Lunds universitet, fortsatte med kompetensutveckling av oss själva och följdes av några utvecklingsprojekt, varefter från grunden förändrade kurser genomfördes under fyra år. Den nya uppläggningen medförde att vi fick positiva attityder i studentenkäterna när det gällde två av kurserna i årskurs 2 i vilken medodiken genomfördes fullständigt. I en kurs, som gavs i årskurs 1 och i vilken den nya uppläggningen endast delvis genomfördes blev studentattityderna negativa.
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- Bolling, Anette Kocbach, et al.
(författare)
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Health effects of residential wood smoke particles : the importance of combustion conditions and physicochemical particle properties
- 2009
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Ingår i: Particle and Fibre Toxicology. - London : BioMed Central (BMC). - 1743-8977. ; 6
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Forskningsöversikt (refereegranskat)abstract
- Background: Residential wood combustion is now recognized as a major particle source in many developed countries, and the number of studies investigating the negative health effects associated with wood smoke exposure is currently increasing. The combustion appliances in use today provide highly variable combustion conditions resulting in large variations in the physicochemical characteristics of the emitted particles. These differences in physicochemical properties are likely to influence the biological effects induced by the wood smoke particles.Outline: The focus of this review is to discuss the present knowledge on physicochemical properties of wood smoke particles from different combustion conditions in relation to wood smoke-induced health effects. In addition, the human wood smoke exposure in developed countries is explored in order to identify the particle characteristics that are relevant for experimental studies of wood smoke-induced health effects. Finally, recent experimental studies regarding wood smoke exposure are discussed with respect to the applied combustion conditions and particle properties.Conclusion: Overall, the reviewed literature regarding the physicochemical properties of wood smoke particles provides a relatively clear picture of how these properties vary with the combustion conditions, whereas particle emissions from specific classes of combustion appliances are less well characterised. The major gaps in knowledge concern; (i) characterisation of the atmospheric transformations of wood smoke particles, (ii) characterisation of the physicochemical properties of wood smoke particles in ambient and indoor environments, and (iii) identification of the physicochemical properties that influence the biological effects of wood smoke particles.
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