| 1. |
- Carlsen, Hanne Krage, et al.
(author)
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Indicators of residential traffic exposure: Modelled NOX, traffic proximity, and self-reported exposure in RHINE III
- 2017
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In: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 167, s. 416-425
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Journal article (peer-reviewed)abstract
- Few studies have investigated associations between self-reported and modelled exposure to traffic pollution. The objective of this study was to examine correlations between self-reported traffic exposure and modelled (a) NOX and (b) traffic proximity in seven different northern European cities; Aarhus (Denmark), Bergen (Norway), Gothenburg, Umeå, and Uppsala (Sweden), Reykjavik (Iceland), and Tartu (Estonia). We analysed data from the RHINE III (Respiratory Health in Northern Europe, www.rhine.nu) cohorts of the seven study cities. Traffic proximity (distance to the nearest road with >10,000 vehicles per day) was calculated and vehicle exhaust (NOX) was modelled using dispersion models and land-use regression (LUR) data from 2011. Participants were asked a question about self-reported traffic intensity near bedroom window and another about traffic noise exposure at the residence. The data were analysed using rank correlation (Kendall's tau) and inter-rater agreement (Cohen's Kappa) between tertiles of modelled NOX and traffic proximity tertile and traffic proximity categories (0–150 metres (m), 150–200 m, >300 m) in each centre. Data on variables of interest were available for 50–99% of study participants per each cohort. Mean modelled NOX levels were between 6.5 and 16.0 μg/m3; median traffic intensity was between 303 and 10,750 m in each centre. In each centre, 7.7–18.7% of respondents reported exposure to high traffic intensity and 3.6–16.3% of respondents reported high exposure to traffic noise. Self-reported residential traffic exposure had low or no correlation with modelled exposure and traffic proximity in all centres, although results were statistically significant (tau = 0.057–0.305). Self-reported residential traffic noise correlated weakly (tau = 0.090–0.255), with modelled exposure in all centres except Reykjavik. Modelled NOX had the highest correlations between self-reported and modelled traffic exposure in five of seven centres, traffic noise exposure had the highest correlation with traffic proximity in tertiles in three centres. Self-reported exposure to high traffic intensity and traffic noise at each participant's residence had low or weak although statistically significant correlations with modelled vehicle exhaust pollution levels and traffic proximity. © 2017
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| 2. |
- Fridell, Erik, et al.
(author)
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A modelling study of the impact on air quality and health due to theemissions from E85 and petrol fuelled cars in Sweden
- 2014
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In: Atmospheric Environment. - : Elsevier. - 1352-2310 .- 1873-2844. ; 82, s. 1-8
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Journal article (peer-reviewed)abstract
- Alternative fuels are becoming more and more important for road traffic and one fuel that has been usedfor several years is ethanol (E85). The main discussion points regarding the environmental performancefor ethanol as a fuel are related to the production. However, there are also some notable differences inthe emissions between E85 and petrol fuelled vehicles. This relates to some extent to the emissions ofnitrogen oxides (NOx) and particulate matter (PM) but mainly to the composition of the emitted organiccompounds. In the present study two fuel scenarios for passenger cars are investigated for the VästraGötaland Region in Sweden; one where the cars with Otto engines run on petrol and one where they runon E85. Two emission scenarios for 2020 are constructed for the whole Europe and coupled dispersionchemistrymodelling is applied to obtain the population exposure to key pollutants. The differencesobtained from the modelling show decreased levels of NOx, ozone and benzene with E85 and increasedlevels of acetaldehyde in the Västra Götaland Region. For the latter the increase may be up to 80%, whileNOx and ozone show decreases of up to a few per cent and a few tenths of per cent, respectively.Exposure to the different air pollutants is calculated as population-weighted concentrations. The healthrisk assessment, using the calculated exposure and published exposureeresponse functions for therelevant pollutants, shows decreased health risks in the E85 scenario relative the all-petrol scenario, dueto the decreased NOx exposure, correlated with both preterm deaths and asthma. However, NOx (andNO2) may partly be indicators of unmeasured causal exhaust components in the epidemiological studiesand thus the exposureeresponse functions for these may not be applicable in the present case wherethere is a difference in NOx exposure but not a proportional difference in exposure to other exhaustcomponents normally associated with NOx. Smaller effects are expected from the changes in ozone,acetaldehyde, PM2.5 and benzene exposure. The overall difference is about 1.6 preterm deaths per yearfor the Västra Götaland Region, with lower values for the E85 scenario, when the uncertain differencesdue to the differences in NOx exposure are not considered.
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| 3. |
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| 4. |
- Götschi, Thomas, et al.
(author)
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Elemental composition and reflectance of ambient fine particles at 21 European locations
- 2005
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In: Atmospheric Environment. - Oxford : Pergamon Press. - 1352-2310 .- 1873-2844. ; 39:32, s. 5947-5958
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Journal article (peer-reviewed)abstract
- We sampled fine particles (PM2.5) over a 1-year period at 21 central urban monitoring sites in 20 cities of the European Community Respiratory Health Survey (ECRHS). Particle filters were then analysed for elemental composition using energy dispersive X-ray fluorescence spectrometry and reflectance (light absorption). Elemental analyses yielded valid results for 15 elements (Al, As, Br, Ca, Cl, Cu, Fe, K, Mn, Pb, S, Si, Ti, V, Zn). Annual and seasonal means Of PM2.5, reflectance, and elements show a wide range across Europe with the lowest levels found in Iceland and up to 80 times higher concentrations in Northern Italy. This pattern holds for most of the air pollution indicators. The mass concentration of S did constitute the largest fraction of the analysed elements Of PM2.5 in all locations. The crustal component varies from less than 10% up to 25% across these cities. Temporal correlations of daily values vary considerably from city to city, depending on the indicators compared. Nevertheless, correlations between estimates of long-term exposure, such as annual means, are generally high among indicators Of PM2.5 from anthropogenic sources, such as S, metals, and reflectance. This highlights the difficulty to disentangle effects of specific sources or PM constituents in future health effect analyses using annual averages.
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| 5. |
- Johansson, Christer, et al.
(author)
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The effects of congestions tax on air quality and health.
- 2009
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In: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 43:31, s. 4843-4854
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Journal article (peer-reviewed)abstract
- The “Stockholm Trial” involved a road pricing system to improve the air quality and reduce traffic congestion. The test period of the trial was January 3–July 31, 2006. Vehicles travelling into and out of the charge cordon were charged for every passage during weekdays. The amount due varied during the day and was highest during rush hours (20 SEK = 2.2 EUR, maximum 60 SEK per day). Based on measured and modelled changes in road traffic it was estimated that this system resulted in a 15% reduction in total road use within the charged cordon. Total traffic emissions in this area of NOx and PM10 fell by 8.5% and 13%, respectively. Air quality dispersion modelling was applied to assess the effect of the emission reductions on ambient concentrations and population exposure. For the situations with and without the trial, meteorological conditions and other emissions than from road traffic were kept the same. The calculations show that, with a permanent congestion tax system like the Stockholm Trial, the annual average NOx concentrations would be lower by up to 12% along the most densely trafficked streets. PM10 concentrations would be up to 7% lower. The limit values for both PM10 and NO2 would still be exceeded along the most densely trafficked streets. The total population exposure of NOx in Greater Stockholm (35 × 35 km with 1.44 million people) is estimated to decrease with a rather modest 0.23 μg m−3. However, based on a long-term epidemiological study, that found an increased mortality risk of 8% per 10 μg m−3 NOx, it is estimated that 27 premature deaths would be avoided every year. According to life-table analysis this would correspond to 206 years of life gained over 10 years per 100 000 people following the trial if the effects on exposures would persist. The effect on mortality is attributed to road traffic emissions (likely vehicle exhaust particles); NOx is merely regarded as an indicator of traffic exposure. This is only the tip of the ice-berg since reductions are expected in both respiratory and cardiovascular morbidity. This study demonstrates the importance of not only assessing the effects on air quality limit values, but also to make quantitative estimates of health impacts, in order to justify actions to reduce air pollution.
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| 6. |
- Malmqvist, Ebba, et al.
(author)
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Assessing ozone exposure for epidemiological studies in Malmo and Umea, Sweden
- 2014
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In: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 94, s. 241-248
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Journal article (peer-reviewed)abstract
- Ground level ozone [ozone] is considered a harmful air pollutant but there is a knowledge gap regarding its long term health effects. The main aim of this study is to develop local Land Use Regression [LUR] models that can be used to study long term health effects of ozone. The specific aim is to develop spatial LUR models for two Swedish cities, Umea and Malmo, as well as a temporal model for Malmo in order to assess ozone exposure for long term epidemiological studies. For the spatial model we measured ozone, using Ogawa passive samplers, as weekly averages at 40 sites in each study area, during three seasons. This data was then inserted in the LUR-model with data on traffic, land use, population density and altitude to develop explanatory models of ozone variation. To develop the temporal model for Malmo, hourly ozone data was aggregated into daily means for two measurement stations in Malmo and one in a rural area outside Malmo. Using regression analyses we inserted meteorological variables into different temporal models and the one that performed best for all three stations was chosen. For Malmo the LUR-model had an adjusted model R-2 of 0.40 and cross validation R-2 of 0.17. For Umea the model had an adjusted model R-2 of 0.67 and cross validation adjusted R-2 of 0.48. When restricting the model to only including measuring sites from urban areas, the Malmo model had adjusted model R-2 of 0.51 (cross validation adjusted R-2 0.33) and the Umea model had adjusted model R-2 of 0.81 (validation adjusted R-2 of 0.73). The temporal model had adjusted model R-2 0.54 and 0.61 for the two Malmo sites, the cross validation adjusted R-2 was 0.42. In conclusion, we can with moderate accuracy, at least for Umea, predict the spatial variability, and in Malmo the temporal variability in ozone variation. (C) 2014 The Authors. Published by Elsevier Ltd.
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| 7. |
- Nawrot, Tim S, et al.
(author)
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Oxidative properties of ambient PM2.5 and elemental composition : heterogeneous associations in 19 European cities
- 2009
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In: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 43:30, s. 4595-4602
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Journal article (peer-reviewed)abstract
- We assessed the extent to which constituents of PM2.5 (transition metals, sodium, chloride) contribute to the ability to generate hydroxyl radicals (OH) in vitro in PM2.5 sampled at 20 locations in 19 European centres participating in the European Community Respiratory Health Survey. PM2.5 samples (n = 716) were collected on filters over one year and the oxidative activity of particle suspensions obtained from these filters was then assessed by measuring their ability to generate OH in the presence of hydrogen peroxide. Associations between OH formation and the studied PM constituents were heterogeneous. The total explained variance ranged from 85% in Norwich to only 6% in Albacete. Among the 20 centres, 15 showed positive correlations between one or more of the measured transition metals (copper, iron, manganese, lead, vanadium and titanium) and OH formation. In 9 of 20 centres OH formation was negatively associated with chloride, and in 3 centres with sodium. Across 19 European cities, elements which explained the largest variations in OH formation were chloride, iron and sodium.
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| 8. |
- Viana, M., et al.
(author)
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Source apportionment of ambient PM2.5 at five Spanish centres of the European Community Respiratory Health Survey (ECRHS II)
- 2007
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In: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 41:7, s. 1395-1406
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Journal article (peer-reviewed)abstract
- Fine particulate matter (PM2.5) was sampled at 5 Spanish locations during the European Community Respiratory Health Survey II (ECRHS II). In an attempt to identify and quantify PM2.5 sources, source contribution analysis by principal component analysis (PCA) was performed on five datasets containing elemental composition of PM2.5 analysed by ED-XRF. A total of 4-5 factors were identified at each site, three of them being common to all sites (interpreted as traffic. mineral and secondary aerosols) whereas industrial sources were site-specific. Sea-salt was identified as independent source at all coastal locations except for Barcelona (where it was clustered with secondary aerosols). Despite their typically dominant coarse grain-size distribution, mineral and marine aerosols were clearly observed in PM2.5. Multi-linear regression analysis (MLRA) was applied to the data, showing that traffic was the main source of PM2.5 at the five sites (39-53% of PM2.5, 5.1-12.0 mu g m(-3)), while regional-scale secondary aerosols accounted for 14-34% of PM2.5 (2.6-4.5 mu g m(-3)), mineral matter for 13-31% (2.4-4.6 mu g m(-3)) and sea-salt made up 3-7% of the PM2.5 mass (0.4-1.3 mu g m(-3)). Consequently, despite regional and climatic variability throughout Spain, the same four main PM2.5 emission sources were identified at all the study sites and the differences between the relative contributions of each of these sources varied at most 20%. This would corroborate PM2.5 as a useful parameter for health studies and environmental policy-making, owing to the fact that it is not as subject to the influence of micro-sitting as other parameters such as PM10. African dust inputs were observed in the mineral source, adding on average 4-11 mu g m(-3) to the PM2.5 daily mean during dust outbreaks. On average, levels of Al, Si, Ti and Fe during African episodes were higher by a factor of 2-8 with respect to non-African days, whereas levels of local pollutants (absorption coefficient, S, Pb, Cl) showed smaller variations (factor of 0.5-2).
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