| 1. |
- Beko, Gabriel, et al.
(författare)
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Contribution of various microenvironments to the daily personal exposure to ultrafine particles: Personal monitoring coupled with GPS tracking
- 2015
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 110, s. 122-129
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Tidskriftsartikel (refereegranskat)abstract
- Exposure to ultrafine particles (UFP) may have adverse health effects. Central monitoring stations do not represent the personal exposure to UFP accurately. Few studies have previously focused on personal exposure to UFP. Sixty non-smoking residents living in Copenhagen, Denmark were asked to carry a backpack equipped with a portable monitor, continuously recording particle number concentrations (PN), in order to measure the real-time individual exposure over a period of similar to 48 h. A GPS logger was carried along with the particle monitor and allowed us to estimate the contribution of UFP exposure occurring in various microenvironments (residence, during active and passive transport, other indoor and outdoor environments) to the total daily exposure. On average, the fractional contribution of each microenvironment to the daily integrated personal exposure roughly corresponded to the fractions of the day the subjects spent in each microenvironment. The home environment accounted for 50% of the daily personal exposure. Indoor environments other than home or vehicles contributed with similar to 40%. The highest median UFP concentration was obtained during passive transport (vehicles). However, being in transit or outdoors contributed 5% or less to the daily exposure. Additionally, the subjects recorded in a diary the periods when they were at home. With this approach, 66% of the total daily exposure was attributable to the home environment. The subjects spent 28% more time at home according to the diary, compared to the GPS. These results may indicate limitations of using diaries, but also possible inaccuracy and miss-classification in the GPS data. (C) 2015 Elsevier Ltd. All rights reserved.
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| 2. |
- Bekö, Gabriel, et al.
(författare)
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Ultrafine Particles: Exposure and Source Apportionment in 56 Danish Homes
- 2013
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Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 1520-5851 .- 0013-936X. ; 47:18, s. 10240-10248
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: Particle number (PN) concentrations (10−300 nm in size) were continuously measured over a period of ∼45 h in 56 residences of nonsmokers in Copenhagen, Denmark. The highest concentrations were measured when occupants were present and awake (geometric mean, GM: 22.3 × 103 cm−3), the lowest when the homes were vacant (GM: 6.1 × 103 cm−3) or the occupants were asleep (GM: 5.1 × 103 cm−3). Diary entries regarding occupancy and particle related activities were used to identify source events and apportion the daily integrated exposure among sources. Source events clearly resulted in increased PN concentrations and decreased average particle diameter. For a given event, elevated particle concentrations persisted for several hours after the emission of fresh particles ceased. The residential daily integrated PN exposure in the 56 homes ranged between 37 × 103 and 6.0 × 106 particles per cm3·h/day (GM: 3.3 × 105 cm−3·h/day). On average, ∼90% of this exposure occurred outside of the period from midnight to 6 a.m. Source events, especially candle burning, cooking, toasting, and unknown activities, were responsible on average for ∼65% of the residential integrated exposure (51% without the unknown activities). Candle burning occurred in half of the homes where, on average, it was responsible for almost 60% of the integrated exposure.
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| 6. |
- Callesen, Michael Thude, et al.
(författare)
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Phthalate metabolites in urine and asthma, allergic rhinoconjunctivitis and atopic dermatitis in preschool children
- 2014
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Ingår i: International journal of hygiene and environmental health (Print). - : Elsevier BV. - 1438-4639 .- 1618-131X. ; 217:6, s. 645-652
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Tidskriftsartikel (refereegranskat)abstract
- Phthalate esters are among the most ubiquitous of indoor pollutants and have been associated with various adverse health effects. In the present study we assessed the cross-sectional association between eight different phthalate metabolites in urine and allergic disease in young children. As part of the Danish Indoor Environment and Children's Health study, urine samples were collected from 440 children aged 3-5 years, of whom 222 were healthy controls, 68 were clinically diagnosed with asthma, 76 with rhinoconjunctivitis and 81 with atopic dermatitis (disease subgroups are not mutually exclusive; some children had more than one disease). There were no statistically significant differences in the urine concentrations of phthalate metabolites between cases and healthy controls with the exception of MnBP and MECPP, which were higher in healthy controls compared with the asthma case group. In the crude analysis MnBP and MiBP were negatively associated with asthma. In the analysis adjusted for multiple factors, only a weak positive association between MEP in urine and atopic dermatitis was found; there were no positive associations between any phthalate metabolites in urine and either asthma or rhinoconjunctivitis. These findings appear to contradict earlier studies. Differences may be due to higher exposures to certain phthalates (e.g., BBzP) via non-dietary pathways in earlier studies, phthalates serving as surrogates for an agent associated with asthma (e.g., PVC flooring) in previous studies but not the present study or altered cleaning habits and the use of "allergy friendly" products by parents of children with allergic disease in the current study in contrast to studies conducted earlier.
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| 7. |
- Clausen, Geo, et al.
(författare)
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Children's health and its association with indoor environments in Danish homes and daycare centres - methods
- 2012
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Ingår i: Indoor Air. - : Hindawi Limited. - 0905-6947 .- 1600-0668. ; 22:6, s. 467-475
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Tidskriftsartikel (refereegranskat)abstract
- The principle objective of the Danish research program 'Indoor Environment and Children's Health' (IECH) was to explore associations between various exposures that children experience in their indoor environments (specifically their homes and daycare centers) and their well-being and health. The targeted health endpoints were allergy, asthma, and certain respiratory symptoms. The study was designed with two stages. In the first stage, a questionnaire survey was distributed to more than 17000 families with children between the ages of 1 and 5. The questionnaire focused on the children's health and the environments within the homes they inhabited and daycare facilities they attended. More than 11000 questionnaires were returned. In the second stage, a subsample of 500 children was selected for more detailed studies, including an extensive set of measurements in their homes and daycare centers and a clinical examination; all clinical examinations were carried out by the same physician. In this study, the methods used for data collection within the IECH research program are presented and discussed. Furthermore, initial findings are presented regarding descriptors of the study population and selected characteristics of the children's dwellings and daycare centers. Practical Implications: This study outlines methods that might be followed by future investigators conducting large-scale field studies of potential connections between various indoor environmental factors and selected health endpoints. Of particular note are (i) the two-stage design - a broad questionnaire-based survey followed by a more intensive set of measurements among a subset of participants who have been selected based on their responses to the questionnaire; (ii) the case-base approach utilized in the stage 2 in contrast to the more commonly used case-control approach; (iii) the inclusion of the children's daycare environment when conducting intensive sampling to more fully capture the children's total indoor exposure; and (iv) all clinical examinations conducted by the same physician. We recognize that future investigators are unlikely to fully duplicate the methods outlined in this study, but we hope that it provides a useful starting point in terms of factors that might be considered when designing such a study.
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| 9. |
- Langer, Sarka, et al.
(författare)
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Phthalate metabolites in urine samples from Danish children and correlations with phthalates in dust samples from their homes and daycare centers
- 2014
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Ingår i: International journal of hygiene and environmental health (Print). - : Elsevier BV. - 1438-4639 .- 1618-131X. ; 217:1, s. 78-87
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Tidskriftsartikel (refereegranskat)abstract
- Around the world humans use products that contain phthalates, and human exposure to certain of these phthalates has been associated with various adverse health effects. The aim of the present study has been to determine the concentrations of the metabolites of diethyl phthalate (DEP), di(n-butyl) phthalate (DnBP), di(iso-butyl) phthalate (DiBP), butyl benzyl phthalate (BBzP) and di(2-ethylhexyl) phthalate (DEHP) in urine samples from 441 Danish children (3-6 years old). These children were subjects in the Danish Indoor Environment and Children's Health study. As part of each child's medical examination, a sample from his or her first morning urination was collected. These samples were subsequently analyzed for metabolites of the targeted phthalates. The measured concentrations of each metabolite were approximately log-normally distributed, and the metabolite concentrations significantly correlated with one another. Additionally, the mass fractions of DEP, DnBP, DiBP and BBzP in dust collected from the children's bedrooms and daycare centers significantly correlated with the concentrations of these phthalates' metabolites (monoethyl phthalate (MEP), mono-n-butyl phthalate (MnBP), mono-isobutyl phthalate (MiBP) and monobenzyl phthalate (MBzP), respectively) in the children's urine. Such correlations indicate that indoor exposures meaningfully contributed to the Danish children's intake of DEP, DnBP, DiBP and BBzP. This was not the case for DEHP. The urine concentrations of the phthalate metabolites measured in the present study were remarkably similar to those measured in urine samples from children living in countries distributed over four continents. These similarities reflect the globalization of children's exposure to phthalate containing products.
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