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| 2. |
- Abera, Asmamaw, et al.
(author)
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Air pollution measurements and land-use regression in urban sub-saharan Africa using low-cost sensors—possibilities and pitfalls
- 2020
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In: Atmosphere. - : MDPI AG. - 2073-4433. ; 11:12
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Journal article (peer-reviewed)abstract
- Air pollution is recognized as the most important environmental factor that adversely affects human and societal wellbeing. Due to rapid urbanization, air pollution levels are increasing in the Sub-Saharan region, but there is a shortage of air pollution monitoring. Hence, exposure data to use as a base for exposure modelling and health effect assessments is also lacking. In this study, low-cost sensors were used to assess PM2.5 (particulate matter) levels in the city of Adama, Ethiopia. The measurements were conducted during two separate 1-week periods. The measurements were used to develop a land-use regression (LUR) model. The developed LUR model explained 33.4% of the variance in the concentrations of PM2.5. Two predictor variables were included in the final model, of which both were related to emissions from traffic sources. Some concern regarding influential observations remained in the final model. Long-term PM2.5 and wind direction data were obtained from the city’s meteorological station, which should be used to validate the representativeness of our sensor measurements. The PM2.5 long-term data were however not reliable. Means of obtaining good reference data combined with longer sensor measurements would be a good way forward to develop a stronger LUR model which, together with improved knowledge, can be applied towards improving the quality of health. A health impact assessment, based on the mean level of PM2.5 (23 µg/m3), presented the attributable burden of disease and showed the importance of addressing causes of these high ambient levels in the area.
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| 3. |
- Abera, Asmamaw, et al.
(author)
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Air Quality in Africa : Public Health Implications
- 2021
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In: Annual review of public health. - : Annual Reviews. - 0163-7525 .- 1545-2093. ; 42, s. 193-210
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Journal article (peer-reviewed)abstract
- This review highlights the importance of air quality in the African urban development process. We address connections between air pollution and (a) rapid urbanization, (b) social problems, (c) health impacts, (d) climate change, (e) policies, and ( f ) new innovations. We acknowledge that air pollution levels in Africa can be extremely high and a serious health threat. The toxic content of the pollution could relate to region-specific sources such as low standards for vehicles and fuels, cooking with solid fuels, and burning household waste. We implore the pursuit of interdisciplinary research to create new approaches with relevant stakeholders. Moreover, successful air pollution research must regard conflicts, tensions, and synergies inherent to development processes in African municipalities, regions, and countries. This includes global relationships regarding climate change, trade, urban planning, and transportation. Incorporating aspects of local political situations (e.g., democracy) can also enhance greater political accountability and awareness about air pollution. Expected final online publication date for the Annual Review of Public Health, Volume 42 is April 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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| 4. |
- Abera, Asmamaw, et al.
(author)
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Measurements of nox and development of land use regression models in an east-African city
- 2021
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In: Atmosphere. - : MDPI AG. - 2073-4433. ; 12:4
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Journal article (peer-reviewed)abstract
- Air pollution causes premature mortality and morbidity globally, but these adverse health effects occur over proportionately in low-and middle-income countries. Lack of both air pollution data and knowledge of its spatial distribution in African countries have been suggested to lead to an underestimation of health effects from air pollution. This study aims to measure nitrogen oxides (NOx), as well as nitrogen dioxide (NO2), to develop Land Use Regression (LUR) models in the city of Adama, Ethiopia. NOx and NO2 was measured at over 40 sites during six days in both the wet and dry seasons. Throughout the city, measured mean levels of NOx and NO2 were 29.0 µg/m3 and 13.1 µg/m3, respectively. The developed LUR models explained 68% of the NOx variances and 75% of the NO2. Both models included similar geographical predictor variables (related to roads, industries, and transportation administration areas) as those included in prior LUR models. The models were validated by using leave-one-out cross-validation and tested for spatial autocorrelation and multicollinearity. The performance of the models was good, and they are feasible to use to predict variance in annual average NOx and NO2 concentrations. The models developed will be used in future epidemiological and health impact assessment studies. Such studies may potentially support mitigation action and improve public health.
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| 5. |
- Abrahamsson, Camilla, et al.
(author)
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Aerosolized particulate matter from fragmentation of carbon nanotube-enhanced concrete
- 2023
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In: 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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Conference paper (peer-reviewed)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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| 6. |
- Abrahamsson, Camilla, et al.
(author)
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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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In: NanoImpact. - 2452-0748. ; 34
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Journal article (peer-reviewed)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 fibers were detected.
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| 7. |
- Abrahamsson, Camilla, et al.
(author)
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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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In: NanoImpact. - : Elsevier B.V.. - 2452-0748. ; 34
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Journal article (peer-reviewed)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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| 8. |
- Ahlberg, Erik, et al.
(author)
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"Vi klimatforskare stödjer Greta och skolungdomarna"
- 2019
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In: Dagens nyheter (DN debatt). - 1101-2447.
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Journal article (pop. science, debate, etc.)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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| 9. |
- 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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