| 1. |
- 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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| 2. |
- Jakobsson, Jonas K F, et al.
(författare)
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Altered deposition of inhaled nanoparticles in subjects with chronic obstructive pulmonary disease
- 2018
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Ingår i: BMC Pulmonary Medicine. - : BioMed Central Ltd.. - 1471-2466. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Respiratory tract deposition of airborne particles is a key link to understand their health impact. Experimental data are limited for vulnerable groups such as individuals with respiratory diseases. The aim of this study is to investigate the differences in lung deposition of nanoparticles in the distal lung for healthy subjects and subjects with respiratory disease. Methods: Lung deposition of nanoparticles (50 and 100 nm) was measured after a 10 s breath-hold for three groups: healthy never-smoking subjects (n = 17), asymptomatic (active and former) smokers (n = 15) and subjects with chronic obstructive pulmonary disease (n = 16). Measurements were made at 1300 mL and 1800 mL volumetric lung depth. Each subject also underwent conventional lung function tests, including post bronchodilator FEV1, VC, and diffusing capacity for carbon monoxide, DL,CO. Patients with previously diagnosed respiratory disease underwent a CT-scan of the lungs. Particle lung deposition fraction, was compared between the groups and with conventional lung function tests. Results: We found that the deposition fraction was significantly lower for subjects with emphysema compared to the other subjects (p = 0.001-0.01), but no significant differences were found between healthy never-smokers and smokers. Furthermore, the particle deposition correlated with pulmonary function tests, FEV1%Pred (p < 0.05), FEV1/VC%Pred (p < 0.01) and DL,CO (p < 0.0005) when all subjects were included. Furthermore, for subjects with emphysema, deposition fraction correlated strongly with DL,CO (Pearson's r = 0.80-0.85, p < 0.002) while this correlation was not found within the other groups. Conclusions: Lower deposition fraction was observed for emphysematous subjects and this can be explained by enlarged distal airspaces in the lungs. As expected, deposition increases for smaller particles and deeper inhalation. The observed results have implications for exposure assessment of air pollution and dosimetry of aerosol-based drug delivery of nanoparticles.
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| 3. |
- Linell, Julia, et al.
(författare)
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Effects of breathing variables on modelled particle lung deposition at physical activity for children and adults
- 2023
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Ingår i: Air Quality, Atmosphere and Health. - : Springer Science and Business Media B.V.. - 1873-9318 .- 1873-9326.
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Tidskriftsartikel (refereegranskat)abstract
- The respiratory tract deposited fraction (DF) is the link between exposure and health effects of airborne particles. Here, we investigate how breathing pattern alterations at increasing physical activity affect DF in different regions of the respiratory tract and compare DF between adults and children (5 and 10 years old). We performed a literature review on the alteration of tidal volume with minute ventilation at increasing physical activity and used the results to model the size resolved (0.001–10 µm) DF, primarily using the deposition models from NCRP and Yeh and Schum (1980), but also MPPD. We found a shift in the deposited size distribution with increasing physical activity—DF of ultrafine particles increased in the alveolar region and decreased in the other regions, while DF of coarser particles decreased in the alveolar region and increased in the extra-thoracic region. Children had a 10–20% higher DF of ultrafine particles in the alveolar region compared to adults. We also present parametrizations of the daily average size resolved (0.005–5 µm) DF, accounting for varying physical activity throughout the day and oral/nasal breathing. These can be applied to any size distribution to estimate deposited doses. We found that deposited mass and number doses were more than twice as high for 5-year-olds compared to adults when normalized for body weight, primarily caused by their higher weight normalized minute ventilation. This demonstrates the importance of studying children’s exposure to air pollution and not only rely on data from adults.
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| 4. |
- Petersson-Sjögren, Madeleine, et al.
(författare)
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Airspace Dimension Assessment with Nanoparticles (AiDA) in Comparison to Established Pulmonary Function Tests
- 2022
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Ingår i: International Journal of Nanomedicine. - : Dove Medical Press Ltd. - 1176-9114 .- 1178-2013. ; 17, s. 2777-2790
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Tidskriftsartikel (refereegranskat)abstract
- Background: Airspace Dimensions Assessment with nanoparticles (AiDA) is a new method for non-invasive measurement of pulmonary distal airspaces. The aim of this study was to compare AiDA measurements with other pulmonary function variables to better understand the potential of AiDA in a clinical context. Methods: AiDA measurements and pulmonary function tests were performed in 695 subjects as part of the Swedish CArdioPulmonary bioImage Study. The measurement protocol included spirometry, measurement of diffusing capacity of carbon monoxide, oscillometry and pulmonary computed tomography. AiDA indices were compared to all other pulmonary examination measurements using multivariate statistical analysis. Results: Our results show that AiDA measurements were significantly correlated with other pulmonary function examination indices, although covariance was low. We found that AiDA variables explained variance in the data that other lung function variables only influenced to a minor extent. Conclusion: We conclude that the AiDA method provides information about the lung that is inaccessible with more conventional lung function techniques. © 2022 Petersson-Sjögren et al.
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| 5. |
- Petersson Sjögren, Madeleine, et al.
(författare)
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Sensitive methods for assessment of lung health in welders and controls
- 2023
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Ingår i: Respiratory Medicine. - : W.B. Saunders Ltd. - 0954-6111 .- 1532-3064. ; 212
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Tidskriftsartikel (refereegranskat)abstract
- Background: Welders are exposed to gas and particle emissions that can cause severe lung disease, such as chronic obstructive pulmonary disease (COPD), a leading cause of mortality and morbidity worldwide. It is difficult to detect COPD early and therefore mitigating measures may be delayed. The aim of this study was to investigate lung health in welders and evaluate new sensitive methods with potential to assess early onset pulmonary changes in occupational settings. Methods: This study assessed the lung health and symptoms in active welders (n = 28) and controls (n = 17). Lung measurements were performed with standard spirometry and new methods: airspace dimension assessment (AiDA), oscillometry, blood serum biomarkers (club cell secretory protein 16, surfactant protein D, matrix metalloproteinases, fibroblast, hepatocyte growth factor, interleukins), and one urine biomarker (desmosine). Results: According to spirometry measurements, all participants had normal lung function. However, prevalence of cough was significantly higher among welders compared with controls and lung changes were found in welders with the novel methods. Welders had significantly higher respiratory system resistance assessed with oscillometry, serum levels of metalloproteinases 9 and hepatocyte growth factor, compared with controls. Airspace dimensions were on average higher among welders compared with controls, but the difference was not significant. The number of welding years correlated with decreased respiratory system reactance and increased serum levels of matrix metalloproteinases 9, interleukin 6, and hepatocyte growth factor. Airspace dimension assessment indices were correlated with increasing levels of inflammatory markers and matrix metalloproteinases. Conclusions: This study indicated the potential to use new and more sensitive methods for identification of changes in lungs when standard spirometry failed to do so. © 2023 The Authors
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| 6. |
- Rissler, Jenny, et al.
(författare)
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A set-up for respiratory tract deposition efficiency measurements (15–5000 nm) and first results for a group of children and adults
- 2017
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Ingår i: Aerosol and Air Quality Research. - : AAGR Aerosol and Air Quality Research. - 1680-8584 .- 2071-1409. ; 17:6, s. 1244-1255
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Tidskriftsartikel (refereegranskat)abstract
- Exposure to airborne particulate matter is associated with a number of negative health effects ranging from respiratorydiseases to systemic effects and cancer. One important factor for understanding the health effects is the individual variationin the respiratory tract deposition of inhaled particles. In this study, we describe an experimental set-up for size-resolvedmeasurements of the lung deposited fraction of airborne particles, covering the diameter range from 15 to 5000 nm. Theset-up includes a system for generating a stable aerosol with a sufficiently broad size distribution. We used a scanningmobility particle sizer and an aerodynamic particle sizer to determine particle number and size. The set-up was used toinvestigate individual differences in the deposition fraction (DF) of particles in the respiratory tract for a group of 67subjects of both sexes aged 7–70 years. The measured DF was applied to two model aerosols, one representing an urbanenvironment and one a rural environment, and the particle deposition rates were derived (i.e., the deposited amount ofparticles per unit time). Furthermore, the deposition rates were normalized to lung surface area and body mass – two dosemeasures that are considered relevant for the health effects of airborne particles. In addition to validation of the set-up, weshow that there is a large individual variation in DF, with some subjects having a DF that is more than twice as high as thatof others. Although we observe differences in the DF between different subgroups, most individual variation wasexplained neither by age nor by gender. When normalizing the deposition rates to lung surface area or body mass, thedeposition rates of children become significantly higher than those of adults. Furthermore, the individual variability islarger for the lung surface area or body mass normalized deposition rates than for DF
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| 7. |
- Rissler, Jenny, et al.
(författare)
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An experimental study on lung deposition of inhaled 2 μm particles in relation to lung characteristics and deposition models
- 2023
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Ingår i: Particle and Fibre Toxicology. - : BioMed Central Ltd. - 1743-8977. ; 20
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Tidskriftsartikel (refereegranskat)abstract
- Background: The understanding of inhaled particle respiratory tract deposition is a key link to understand the health effects of particles or the efficiency for medical drug delivery via the lung. However, there are few experimental data on particle respiratory tract deposition, and the existing data deviates considerably when comparing results for particles > 1 μm. Methods: We designed an experimental set-up to measure deposition in the respiratory tract for particles > 1 μm, more specifically 2.3 μm, with careful consideration to minimise foreseen errors. We measured the deposition in seventeen healthy adults (21–68 years). The measurements were performed at tidal breathing, during three consecutive 5-minute periods while logging breathing patterns. Pulmonary function tests were performed, including the new airspace dimension assessment (AiDA) method measuring distal lung airspace radius (r AiDA). The lung characteristics and breathing variables were used in statistical models to investigate to what extent they can explain individual variations in measured deposited particle fraction. The measured particle deposition was compared to values predicted with whole lung models. Model calculations were made for each subject using measured variables as input (e.g., breathing pattern and functional residual capacity). Results: The measured fractional deposition for 2.3 μm particles was 0.60 ± 0.14, which is significantly higher than predicted by any of the models tested, ranging from 0.37 ± 0.08 to 0.53 ± 0.09. The multiple-path particle dosimetry (MPPD) model most closely predicted the measured deposition when using the new PNNL lung model. The individual variability in measured particle deposition was best explained by breathing pattern and distal airspace radius (r AiDA) at half inflation from AiDA. All models underestimated inter-subject variability even though the individual breathing pattern and functional residual capacity for each participant was used in the model. Conclusions: Whole lung models need to be tuned and improved to predict the respiratory tract particle deposition of micron-sized particles, and to capture individual variations – a variation that is known to be higher for aged and diseased lungs. Further, the results support the hypothesis that the AiDA method measures dimensions in the peripheral lung and that r AiDA, as measured by the AiDA, can be used to better understand the individual variation in the dose to healthy and diseased lungs.
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| 8. |
- Rissler, Jenny, et al.
(författare)
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Deposition efficiency of inhaled particles (15-5000 nm) related to breathing pattern and lung function : An experimental study in healthy children and adults
- 2017
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Ingår i: Particle and Fibre Toxicology. - : Springer Science and Business Media LLC. - 1743-8977. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Exposure to airborne particles has a major impact on global health. The probability of these particles to deposit in the respiratory tract during breathing is essential for their toxic effects. Observations have shown that there is a substantial variability in deposition between subjects, not only due to respiratory diseases, but also among individuals with healthy lungs. The factors determining this variability are, however, not fully understood. Method: In this study we experimentally investigate factors that determine individual differences in the respiratory tract depositions of inhaled particles for healthy subjects at relaxed breathing. The study covers particles of diameters 15-5000 nm and includes 67 subjects aged 7-70 years. A comprehensive examination of lung function was performed for all subjects. Principal component analyses and multiple regression analyses were used to explore the relationships between subject characteristics and particle deposition. Results: A large individual variability in respiratory tract deposition efficiency was found. Individuals with high deposition of a certain particle size generally had high deposition for all particles <3500 nm. The individual variability was explained by two factors: breathing pattern, and lung structural and functional properties. The most important predictors were found to be breathing frequency and anatomical airway dead space. We also present a linear regression model describing the deposition based on four variables: tidal volume, breathing frequency, anatomical dead space and resistance of the respiratory system (the latter measured with impulse oscillometry). Conclusions: To understand why some individuals are more susceptible to airborne particles we must understand, and take into account, the individual variability in the probability of particles to deposit in the respiratory tract by considering not only breathing patterns but also adequate measures of relevant structural and functional properties.
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