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  • 1.
    Ahmed, Trifa M.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ahmed, Baram
    Aziz, Bakhtyar K.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Native and oxygenated polycyclic aromatic hydrocarbons in ambient air particulate matter from the city of Sulaimaniyah in Iraq2015In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 116, p. 44-50Article in journal (Refereed)
    Abstract [en]

    The concentrations of 43 polycyclic aromatic hydrocarbons (PAHs) and 4 oxygenated PAHs (OPAHs) are reported for the first time in particulate matter (PM10) sampled in the air of the city of Sulaimaniyah in Iraq. The total PAH concentration at the different sampling sites varied between 9.3 and 114 ng/m(3). The corresponding values of the human carcinogen benzotalpyrene were between 0.3 and 6.9 ng/m(3), with most samples exceeding the EU annual target value of 1 ng/m(3). The highly carcinogenic dibenzopyrene isomers dibenzo[a,l]pyrene, dibenzo[a,e]pyrene, dibenzo[a,i]pyrene and dibenzo[a,h]pyrene constituted 0.1-0.4% of the total PAH concentration. However, when scaling for relative cancer potencies using toxic equivalency factors, a benzo[a]pyrene equivalent concentration of dibenzo[a,l]pyrene equal to that of benzo[a]pyrene was obtained, indicating that the contribution of dibenzo[a,l]pyrene to the carcinogenicity of the PAHs could be similar to that of benzo[a]pyrene. A high correlation between the determined concentrations of the dibenzopyrene isomers and benzo[a]pyrene was found, which supported the use of benzo[a]pyrene as an indicator for the carcinogenicity of PAHs in ambient air. The total concentrations of the four OPAHs, 9,10-anthraquinone, 4H-cyclopenta[def]phenanthren-4-one, benzanthrone, and 7,12-benz[a]anthraquinone, varied between 0.6 and 8.1 ng/m(3), with 9,10-anthraquinone being the most abundant OPAH in all of the samples.

  • 2.
    Amorim, Jorge Humberto
    et al.
    SMHI, Research Department, Air quality.
    Valente, J.
    Cascao, P.
    Ribeiro, L. M.
    Viegas, D. X.
    Ottmar, R.
    Miranda, A. I.
    Near-source grid-based measurement of CO and PM2.5 concentration during a full-scale fire experiment in southern European shrubland2016In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 145, p. 19-28Article in journal (Refereed)
  • 3.
    Andersson, August
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Sheesley, Rebecca J.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Krusa, Martin
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Johansson, Christer
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Gustafsson, Örjan
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    (14)C-Based source assessment of soot aerosols in Stockholm and the Swedish EMEP-Aspvreten regional background site2011In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 45, no 1, p. 215-222Article in journal (Refereed)
    Abstract [en]

    Combustion-derived soot or black carbon (BC) in the atmosphere has a strong influence on both climate and human health. In order to propose effective mitigation strategies for BC emissions it is of importance to investigate geographical distributions and seasonal variations of BC emission sources. Here, a radiocarbon methodology is used to distinguish between fossil fuel and biomass burning sources of soot carbon (SC). SC is isolated for subsequent off-line (14)C quantification with the chemothermal oxidation method at 375 degrees C (CTO-375 method), which reflects a recalcitrant portion of the BC continuum known to minimize inadvertent inclusion of any non-pyrogenic organic matter. Monitored wind directions largely excluded impact from the Stockholm metropolitan region at the EMEP-Aspvreten rural station 70 km to the south-west. Nevertheless, the Stockholm city and the rural stations yielded similar relative source contributions with fraction biomass (f(biomass)) for fall and winter periods in the range of one-third to half. Large temporal variations in (14)C-based source apportionment was noted for both the 6 week fall and the 4 month winter observations. The f(biomass) appeared to be related to the SC concentration suggesting that periods of elevated BC levels may be caused by increased wood fuel combustion. These results for the largest metropolitan area in Scandinavia combine with other recent (14)C-based studies of combustion-derived aerosol fractions to suggest that biofuel combustion is contributing a large portion of the BC load to the northern European atmosphere.

  • 4.
    Andersson, Camilla
    et al.
    SMHI, Research Department, Air quality.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Johansson, Christer
    Population exposure and mortality due to regional background PM in Europe - Long-term simulations of source region and shipping contributions2009In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 43, no 22-23, p. 3614-3620Article in journal (Refereed)
    Abstract [en]

    This paper presents the contribution to population exposure (PE) of regional background fine primary (PPM(2.5)) and secondary inorganic (SIA) particulate matter and its impact on mortality in Europe during 1997-2003 calculated with a chemistry transport model. Contributions to concentrations and PE due to emissions from shipping, Western (WEU), Eastern (EEU), and Northern Europe are compared. WEU contributes about 40% to both PPM(2.5) and SIA concentrations, whereas the EEU contribution to PPM(2.5) is much higher (43% of total PPM(2.5)) than to SIA (29% of total SIA). The population weighted average concentration (PWC) of PPM(2.5) is a factor of 2.3 higher than average (non-weighted) concentrations, whereas for SIA the PWC is only a factor 1.6 higher. This is due to PPM(2.5) concentrations having larger gradients and being relatively high over densely populated areas, whereas SIA is formed outside populated areas. WEU emissions contribute relatively more than EEU to PWC and mortality due to both PPM(2.5) and SIA in Europe. The number of premature deaths in Europe is estimated to 301000 per year due to PPM(2.5) exposure and 245 000 due to SIA, despite 3.3 times higher average SIA concentrations. This is due to population weighting and assumed (and uncertain) higher relative risk of mortality for PPM(2.5) components (2.8 times higher RR for PPM(2.5)). This study indicates that it might be more efficient, for the health of the European population, to decrease primary PM emissions (especially in WEU) than to decrease precursors of SIA, but more knowledge on the toxicity of different PM constituents is needed before firm conclusions can be drawn. (C) 2009 Elsevier Ltd. All rights reserved.

  • 5.
    Andersson, Camilla
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Bergström, Robert
    Johansson, Christer
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Population exposure and mortality due to regional background PM in Europe – longterm simulations of source-region and shipping contributions2009In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 43, no 22-23, p. 3614-3620Article in journal (Refereed)
    Abstract [en]

    This paper presents the contribution to population exposure (PE) of regional background fine primary (PPM2.5) and secondary inorganic (SIA) particulate matter and its impact on mortality in Europe during 1997–2003 calculated with a chemistry transport model. Contributions to concentrations and PE due to emissions from shipping, Western (WEU), Eastern (EEU), and Northern Europe are compared.

    WEU contributes about 40% to both PPM2.5 and SIA concentrations, whereas the EEU contribution to PPM2.5 is much higher (43% of total PPM2.5) than to SIA (29% of total SIA). The population weighted average concentration (PWC) of PPM2.5 is a factor of 2.3 higher than average (non-weighted) concentrations, whereas for SIA the PWC is only a factor 1.6 higher. This is due to PPM2.5 concentrations having larger gradients and being relatively high over densely populated areas, whereas SIA is formed outside populated areas. WEU emissions contribute relatively more than EEU to PWC and mortality due to both PPM2.5 and SIA in Europe.

    The number of premature deaths in Europe is estimated to 301 000 per year due to PPM2.5 exposure and 245 000 due to SIA, despite 3.3 times higher average SIA concentrations. This is due to population weighting and assumed (and uncertain) higher relative risk of mortality for PPM2.5 components (2.8 times higher RR for PPM2.5). This study indicates that it might be more efficient, for the health of the European population, to decrease primary PM emissions (especially in WEU) than to decrease precursors of SIA, but more knowledge on the toxicity of different PM constituents is needed before firm conclusions can be drawn.

  • 6.
    Arrhenius, Karine
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Organisk kemi (Kmo).
    Rosell, Lars
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Organisk kemi (Kmo).
    Bäfver, Linda
    Analysis of unregulated emissions from an off-road diesel engine during realistic work operations2011In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 45, no 30, p. 5394-5398Article in journal (Refereed)
  • 7. Avagyan, Rozanna
    et al.
    Nyström, Robin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lindgren, Robert
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Westerholm, Roger
    Particulate hydroxy-PAH emissions from a residential wood log stove using different fuels and burning conditions2016In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 140, p. 1-9Article in journal (Refereed)
    Abstract [en]

    Hydroxylated polycyclic aromatic hydrocarbons are oxidation products of polycyclic aromatic hydrocarbons, but have not been studied as extensively as polycyclic aromatic hydrocarbons. Several studies have however shown that hydroxylated polycyclic aromatic hydrocarbons have toxic and carcinogenic properties. They have been detected in air samples in semi urban areas and combustion is assumed to be the primary source of those compounds. To better understand the formation and occurrence of particulate hydroxylated polycyclic aromatic hydrocarbons from residential wood log stove combustion, 9 hydroxylated polycyclic aromatic hydrocarbons and 2 hydroxy biphenyls were quantified in particles generated from four different types of wood logs (birch, spruce, pine, aspen) and two different combustion conditions (nominal and high burn rate). A previously developed method utilizing liquid chromatography photo ionization tandem mass spectrometry and pressurized liquid extraction was used. Polycyclic aromatic hydrocarbons were analyzed along with hydroxylated polycyclic aromatic hydrocarbons. The hydroxylated polycyclic aromatic hydrocarbon emissions varied significantly across different wood types and burning conditions; the highest emissions for nominal burn rate were from spruce and for high burn rate from pine burning. Emissions from nominal burn rate corresponded on average to 15% of the emissions from high burn rate, with average emissions of 218 mu g/MJ(fuel) and 32.5 mu g/MJ(fuel) for high burn rate and nominal burn rate, respectively. Emissions of the measured hydroxylated polycyclic aromatic hydrocarbons corresponded on average to 28% of polycyclic aromatic hydrocarbons emissions. This study shows that wood combustion is a large emission source of hydroxylated polycyclic aromatic hydrocarbons and that not only combustion conditions, but also wood type influences the emissions of hydroxylated polycyclic aromatic hydrocarbons and polycyclic aromatic hydrocarbons. There are few studies that have determined hydroxylated polycyclic aromatic hydrocarbons in emissions from wood combustion, and it is therefore necessary to further investigate the formation, occurrence and distribution of these compounds as they are present in significant amounts in wood smoke particles.

  • 8.
    Avagyan, Rozanna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Nyström, Robin
    Lindgren, Robert
    Boman, Christoffer
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Particulate hydroxy-PAH emissions from a residential wood log stove using different fuels and burning conditions2016In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 140, p. 1-9Article in journal (Refereed)
    Abstract [en]

    Hydroxylated polycyclic aromatic hydrocarbons are oxidation products of polycyclic aromatic hydrocarbons, but have not been studied as extensively as polycyclic aromatic hydrocarbons. Several studies have however shown that hydroxylated polycyclic aromatic hydrocarbons have toxic and carcinogenic properties. They have been detected in air samples in semi urban areas and combustion is assumed to be the primary source of those compounds. To better understand the formation and occurrence of particulate hydroxylated polycyclic aromatic hydrocarbons from residential wood log stove combustion, 9 hydroxylated polycyclic aromatic hydrocarbons and 2 hydroxy biphenyls were quantified in particles generated from four different types of wood logs (birch, spruce, pine, aspen) and two different combustion conditions (nominal and high burn rate). A previously developed method utilizing liquid chromatography photo ionization tandem mass spectrometry and pressurized liquid extraction was used. Polycyclic aromatic hydrocarbons were analyzed along with hydroxylated polycyclic aromatic hydrocarbons. The hydroxylated polycyclic aromatic hydrocarbon emissions varied significantly across different wood types and burning conditions; the highest emissions for nominal burn rate were from spruce and for high burn rate from pine burning. Emissions from nominal burn rate corresponded on average to 15% of the emissions from high burn rate, with average emissions of 218 mu g/MJ(fuel) and 32.5 mu g/MJ(fuel) for high burn rate and nominal burn rate, respectively. Emissions of the measured hydroxylated polycyclic aromatic hydrocarbons corresponded on average to 28% of polycyclic aromatic hydrocarbons emissions. This study shows that wood combustion is a large emission source of hydroxylated polycyclic aromatic hydrocarbons and that not only combustion conditions, but also wood type influences the emissions of hydroxylated polycyclic aromatic hydrocarbons and polycyclic aromatic hydrocarbons. There are few studies that have determined hydroxylated polycyclic aromatic hydrocarbons in emissions from wood combustion, and it is therefore necessary to further investigate the formation, occurrence and distribution of these compounds as they are present in significant amounts in wood smoke particles.

  • 9.
    Baduel, Christine
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Nozière, Barbara
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Jaffrezo, Jean-Luc
    Summer/winter variability of the surfactants in aerosols from Grenoble, France2012In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 47, p. 413-420Article in journal (Refereed)
    Abstract [en]

    Many atmospheric aerosols seem to contain strong organic surfactants likely to enhance their cloud-forming properties. Yet, few techniques allow for the identification and characterization of these compounds. Recently, we introduced a double extraction method to isolate the surfactant fraction of atmospheric aerosol samples, and evidenced their very low surface tension (<= 30 mN m(-1)). In this work, this analytical procedure was further optimized. In addition to an optimized extraction and a reduction of the analytical time, the improved method led to a high reproducibility in the surface tension curves obtained (shapes and minimal values), illustrated by the low uncertainties on the values, +/- 10% or less. The improved method was applied to PM10 aerosols from the urban area of Grenoble, France collected from June 2009 to January 2010. Significant variability was observed between the samples. The minimum surface tension obtained from the summer samples was systematically lower (30 mN m(-1)) than that of the winter samples (35-45 mN m(-1)). Sharp transitions in the curves together with the very low surface tensions suggested that the dominating surfactants in the summer samples were biosurfactants, which would be consistent with the high biogenic activity in that season. One group of samples from the winter also displayed sharp transitions, which, together with the slightly higher surface tension, suggested the presence of weaker, possibly man-made, surfactants. A second group of curves from the winter did not display any clear transition but were similar to those of macromolecular surfactants such as polysaccharides or humic substances from wood burning. These surfactants are thus likely to originate from wood burning, the dominating source for aerosols in Grenoble in winter. These observations thus confirm the presence of surfactants from combustion processes in urban aerosols reported by other groups and illustrates the ability of our method to distinguish between different types of surfactants in atmospheric samples.

  • 10. Beelen, Rob
    et al.
    Hoek, Gerard
    Vienneau, Danielle
    Eeftens, Marloes
    Dimakopoulou, Konstantina
    Pedeli, Xanthi
    Tsai, Ming-Yi
    Künzli, Nino
    Schikowski, Tamara
    Marcon, Alessandro
    Eriksen, Kirsten
    Raaschou-Nielsen, Ole
    Stephanou, Euripides
    Evridiki, Patelarou
    Lanki, Timo
    Yli-Tuomi, Tarja
    Declercq, Christophe
    Falq, Grégoire
    Stempfelet, Morgane
    Birk, Matthias
    Cyrys, Josef
    von Klot, Stephanie
    Nádor, Gizella
    Varró, Mihály János
    Dėdelė, Audrius
    Gražulevičienė, Regina
    Mölter, Anna
    Lindley, Sarah
    Madsen, Christian
    Cesaroni, Giulia
    Ranzi, Andrea
    Badaloni, Chiara
    Hoffmann, Barbara
    Nonnemacher, Michael
    Krämer, Ursula
    Kuhlbusch, Thomas
    Cirach, Marta
    de Nazelle, Audrey
    Nieuwenhuijsen, Mark
    Bellander, Tom
    Korek, Michal
    Olsson, David
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Strömgren, Magnus
    Umeå University, Faculty of Social Sciences, Department of Geography and Economic History.
    Dons, Evi
    Jerrett, Michael
    Fischer, Paul
    Brunekreef, Bert
    de Hoogh, Kees
    Development of NO2 and NOx land use regression models for estimating air pollution exposure in 36 study areas in Europe: the ESCAPE project2013In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 72, p. 10-23Article in journal (Refereed)
    Abstract [en]

    Estimating within-city variability in air pollution concentrations is important. Land use regression (LUR) models are able to explain such small-scale within-city variations. Transparency in LUR model development methods is important to facilitate comparison of methods between different studies. We therefore developed LUR models in a standardized way in 36 study areas in Europe for the ESCAPE (European Study of Cohorts for Air Pollution Effects) project.

    Nitrogen dioxide (NO2) and nitrogen oxides (NOx) were measured with Ogawa passive samplers at 40 or 80 sites in each of the 36 study areas. The spatial variation in each area was explained by LUR modeling. Centrally and locally available Geographic Information System (GIS) variables were used as potential predictors. A leave-one out cross-validation procedure was used to evaluate the model performance.

    There was substantial contrast in annual average NO2 and NOx concentrations within the study areas. The model explained variances (R2) of the LUR models ranged from 55% to 92% (median 82%) for NO2 and from 49% to 91% (median 78%) for NOx. For most areas the cross-validation R2 was less than 10% lower than the model R2. Small-scale traffic and population/household density were the most common predictors. The magnitude of the explained variance depended on the contrast in measured concentrations as well as availability of GIS predictors, especially traffic intensity data were important. In an additional evaluation, models in which local traffic intensity was not offered had 10% lower R2 compared to models in the same areas in which these variables were offered.

    Within the ESCAPE project it was possible to develop LUR models that explained a large fraction of the spatial variance in measured annual average NO2 and NOx concentrations. These LUR models are being used to estimate outdoor concentrations at the home addresses of participants in over 30 cohort studies.

  • 11.
    Bergvall, Christoffer
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Determination of highly carcinogenic dibenzopyrene isomers in particulate emissions from two diesel- and two gasoline-fuelled light-duty vehicles2009In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 43, no 25, p. 3883-3890Article in journal (Refereed)
    Abstract [en]

    Emission factors of particulate-bound Polycyclic Aromatic Hydrocarbons (PAHs) including benzo(a)pyrene and, for the first time, the highly carcinogenic dibenzo(a,l)pyrene, dibenzo(a,e)pyrene, dibenzo(a,i)pyrene and dibenzo(a,h)pyrene have been determined in exhausts from two diesel- (DFVs) and two gasoline-fuelled light-duty vehicles (GFVs) operated in the Urban (AU), Rural Road (AR) and Motorway (AM) transient ARTEMIS driving cycles. The obtained results showed the DFVs to emit higher amounts of PAHs than the GFVs per km driving distance at low average speed in the AU driving cycle, while the GFVs emitted higher amounts of PAHs than the DFVs per km driving distance at higher average speeds in the AR and AM driving cycles. Furthermore, the study showed an increase in PAH emissions per km driving distance with increasing average speed for the GFVs with the opposite trend found for the DFVs. The GFVs generated particulate matter with higher PAH content than the DFVs in all three driving cycles tested with the highest concentrations obtained in the AR driving cycle. Dibenzo(a,l)pyrene was found to be a major contributor to the potential carcinogenicity accounting for 58–67% and 25–31% of the sum added potential carcinogenicity of the measured PAHs in the emitted particulate matter from the DFVs and GFVs, respectively. Corresponding values for benzo(a)pyrene were 16–25% and 11–40% for the DFVs and GFVs, respectively. The DFVs displayed higher sum added potential carcinogenicity of the measured PAHs than the GFVs in the AU driving cycle with the opposite trend found in the AR and AM driving cycles. The findings of this study show the importance of including the dibenzopyrenes in vehicle exhaust chemical characterizations to avoid potential underestimation of the carcinogenic activity of the emissions. The lower emissions and the lower sum added potential carcinogenicity of the measured PAHs found in this study for the GFVs compared to the DFVs in the AU driving cycle indicate the GFVs to be preferred in dense urban areas with traffic moving at low average speeds with multiple start and stops. However, the obtained results suggest the opposite to be true at higher average speeds with driving at rural roads and motorways. Further studies are, however, needed to establish if the observed differences between GFVs and DFVs are generally valid as well as to study the effects on variations in vehicle/engine type, ambient temperature, fuel and driving conditions on the emission factors.

  • 12. Borrego, C.
    et al.
    Amorim, Jorge Humberto
    SMHI, Research Department, Air quality.
    Tchepel, O.
    Dias, D.
    Rafael, S.
    Sa, E.
    Pimentel, C.
    Fontes, T.
    Fernandes, P.
    Pereira, S. R.
    Bandeira, J. M.
    Coelho, M. C.
    Urban scale air quality modelling using detailed traffic emissions estimates2016In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 131, p. 341-351Article in journal (Refereed)
    Abstract [en]

    The atmospheric dispersion of NOx and PM10 was simulated with a second generation Gaussian model over a medium-size south-European city. Microscopic traffic models calibrated with GPS data were used to derive typical driving cycles for each road link, while instantaneous emissions were estimated applying a combined Vehicle Specific Power/Co-operative Programme for Monitoring and Evaluation of the Long-range Transmission of Air Pollutants in Europe (VSP/EMEP) methodology. Site-specific background concentrations were estimated using time series analysis and a low-pass filter applied to local observations. Air quality modelling results are compared against measurements at two locations for a 1 week period. 78% of the results are within a factor of two of the observations for 1-h average concentrations, increasing to 94% for daily averages. Correlation significantly improves when background is added, with an average of 0.89 for the 24 h record. The results highlight the potential of detailed traffic and instantaneous exhaust emissions estimates, together with filtered urban background, to provide accurate input data to Gaussian models applied at the urban scale. (C) 2016 Elsevier Ltd. All rights reserved.

  • 13.
    Buccoliere, Riccardo
    et al.
    Univ Salento, Dipartimento Sci Mat, Lecce, Italy, and Univ Ca Foscari Venezia, Dipartimento Informat, Venice, Italy.
    Sandberg, Mats
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Building science - installation technology.
    Di Sabatino, Silvana
    Univ Salento, Dipartimento Sci Mat, Lecce, Italy .
    City breathability and its link to pollutant concentration distribution within urban-like geometries2010In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 44, no 15, p. 1894-1903Article in journal (Refereed)
    Abstract [en]

    This paper is devoted to the study of pollutant concentration distribution within urban-like geometries. By applying efficiency concepts originally developed for indoor environments, the term ventilation is used as a measure of city “breathability”. It can be applied to analyse pollutant removal within a city in operational contexts. This implies the evaluation of the bulk flow balance over the city and of the mean age of air. The influence of building packing density on flow and pollutant removal is, therefore, evaluated using those quantities. Idealized cities of regular cubical buildings were created with packing density ranging from 6.25% to 69% to represent configurations from urban sprawl to compact cities. The relative simplicity of these arrangements allowed us to apply the Computational Fluid Dynamics (CFD) flow and dispersion simulations using the standard k turbulence model. Results show that city breathability within the urban canopy layer is strongly dependent from the building packing density. At the lower packing densities, the city responds to the wind as an agglomeration of obstacles, at larger densities (from about 44%) the city itself responds as a single obstacle. With the exception of the lowest packing density, airflow enters the array through lateral sides and leaves throughout the street top and flow out downstream. The air entering through lateral sides increases with increasing packing density.

    At the street top of the windward side of compact building configurations, a large upward flow is observed. This vertical transport reduces over short distance to turn into a downward flow further downstream of the building array. These findings suggest a practical way of identifying city breathability. Even though the application of these results to real scenarios require further analyses the paper illustrates a practical framework to be adopted in the assessment of the optimum neighbourhood building layout to minimize pollution levels.

  • 14. Buccolieri, Riccardo
    et al.
    Sandberg, Mats
    KTH Research School University of Gävle, Department of Indoor Environment.
    Di Sabatino, Silvana
    City breathability and its link to pollutant concentration distribution within urban-like geometries2010In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 44, no 15, p. 1894-1903Article in journal (Refereed)
    Abstract [en]

    This paper is devoted to the study of pollutant concentration distribution within urban-like geometries. By applying efficiency concepts originally developed for indoor environments, the term ventilation is used as a measure of city "breathability". It can be applied to analyse pollutant removal within a city in operational contexts. This implies the evaluation of the bulk flow balance over the city and of the mean age of air. The influence of building packing density on flow and pollutant removal is, therefore, evaluated using those quantities. Idealized cities of regular cubical buildings were created with packing density ranging from 6.25% to 69% to represent configurations from urban sprawl to compact cities. The relative simplicity of these arrangements allowed us to apply the Computational Fluid Dynamics (CFD) flow and dispersion simulations using the standard k-epsilon turbulence model. Results show that city breathability within the urban canopy layer is strongly dependent from the building packing density. At the lower packing densities, the city responds to the wind as an agglomeration of obstacles, at larger densities (from about 44%) the city itself responds as a single obstacle. With the exception of the lowest packing density, airflow enters the array through lateral sides and leaves throughout the street top and flow out downstream. The air entering through lateral sides increases with increasing packing density. At the street top of the windward side of compact building configurations, a large upward flow is observed. This vertical transport reduces over short distance to turn into a downward flow further downstream of the building array. These findings suggest a practical way of identifying city breathability. Even though the application of these results to real scenarios require further analyses the paper illustrates a practical framework to be adopted in the assessment of the optimum neighbourhood building layout to minimize pollution levels.

  • 15. Budhavant, K. B.
    et al.
    Rao, P. S. P.
    Safai, P. D.
    Granat, L.
    Rodhe, Henning
    Stockholm University, Faculty of Science, Department of Meteorology .
    Chemical composition of the inorganic fraction of cloud-water at a high altitude site in West India2014In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 88, p. 59-65Article in journal (Refereed)
    Abstract [en]

    Data from a ground-based cloud-water collection system intercepting water from clouds at a mountain field station, Sinhagad near Pune in India are presented. This study was part of an Indo-Swedish Collaboration Project on Atmospheric Brown Cloud-Asia (ABC-A). Cloud-water and rainwater (wet-only) samples were collected during June 2007-Dec. 2010. Concentrations of major anions and cations were determined. Ion concentrations were generally higher (NO3-, about 8 times; SO42- and K+, 5 times; NH4+ times and Cl-, Na+, Ca2+, Mg2+ 3 times) in cloud-water samples than in rainwater samples collected during the same days. The average pH of cloud-water samples was 6.0 with about 20% of the values below 5.6 and only 4% less than 5.0. Despite high concentrations of SO42- and NO3- the cloud water samples were on average not more acidic than rainwater samples. This is different from most of the other studies of cloud-water composition which have noted a substantially higher acidity (i.e. lower pH) in cloud-water than in rainwater. The slightly alkaline (pH > 5.6) nature of the cloud-water samples is mainly due to the presence of soil derived calcium carbonate in quantities more than enough to neutralize the acids or their precursors. A separation of the cloud-water data into trajectory groups showed that samples in air-masses having spent the last few days over the Indian sub-continent were in general more acidic (due to anthropogenic emissions) than those collected during days with air-masses of marine origin. A high correlation mutually between Ca2+, Na+, NO3- and SO42- makes it difficult to estimate the contribution to SO42- from different sources. Anthropogenic SO2- emissions and soil dust may both give important contributions.

  • 16. Budhavant, K. B.
    et al.
    Rao, P. S. P.
    Safai, P. D.
    Leck, Caroline
    Stockholm University, Faculty of Science, Department of Meteorology .
    Rodhe, Henning
    Stockholm University, Faculty of Science, Department of Meteorology .
    Black carbon in cloud-water and rain water during monsoon season at a high altitude station in India2016In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 129, p. 256-264Article in journal (Refereed)
    Abstract [en]

    We present results of measurements of black carbon (BC) from ground-based wet-only rainwater (RW) and cloud-water (CW) sampling at a mountain field station, Sinhagad, situated in south western India during the period from June 2008 to October 2010. The amount of BC in the sample was determined by photometry at a wavelength of 528 nm after a procedure including the filtration through a 0.4 mu m polycarbonate membrane filter. Water soluble concentrations of major anions in RW and CW were also determined. The average concentration of BC in RW (16 mu mol dm(-3)) is higher by at least a factor 2 than that found in similar studies reported from other parts of the world. On the other hand, the average concentration of BC in CW (47 mu mol dm(-3)) is lower by about a factor of 2 than that found at other sites. The ratio between the average concentrations in CW and RW varies from 2 (K+) to 7 (SO42-). The ratio for BC was about 3. No significant difference was observed for pH. Analysis of air mass back trajectories and of correlations between the various components indicates that long range transport of pollutants and dust from East Africa and Southern part of the Arabian peninsula might contribute to the high concentrations of BC and some of the ionic constituents at Sinhagad during the monsoon season.

  • 17.
    Burman, Jan
    et al.
    Swedish Def Res Agcy, Div CBRN Def & Secur, FOI, SE-90182 Umea, Sweden..
    Jonsson, Lage
    Swedish Def Res Agcy, Div CBRN Def & Secur, FOI, SE-90182 Umea, Sweden.; Royal Inst Technol, KTH, SE-10044 Stockholm, Sweden..
    Issues when linking computational fluid dynamics for urban modeling to toxic load models: The need for further research2015In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 104, p. 112-124Article in journal (Refereed)
    Abstract [en]

    In order to predict casualties caused by chemical hazards in densely populated areas, state-of-the-art Computational Fluid Dynamic (CFD) techniques could be utilized together with toxic load models. In the current study, simulations of consequences of hypothetical releases of toxic gas in a city center are presented and discussed. CFD models that reproduce flow statistics would be most appropriate for this purpose since it could be expected that they will more realistically represent the environment. However, since concentration-peaks in the ever-present spatiotemporal fluctuations of airborne chemicals contribute so much to the toxic load, it is shown that straight-forward direct linking of a CFD model to a toxic load model is not a suitable approach for predicting consequences of a toxic release. Furthermore, it is demonstrated that the use of different turbulence models leads to different casualty assessments. Obviously, there is an urgent need to establish widely accepted methods, ideally with known uncertainty measures. Thus, further research in this area is of great importance.

  • 18. Burman, Jan
    et al.
    Jonsson, Lage
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Issues when linking computational fluid dynamics for urban modeling to toxic load models: The need for further research2015In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 104, p. 112-124Article in journal (Refereed)
    Abstract [en]

    In order to predict casualties caused by chemical hazards in densely populated areas, state-of-the-art Computational Fluid Dynamic (CFD) techniques could be utilized together with toxic load models. In the current study, simulations of consequences of hypothetical releases of toxic gas in a city center are presented and discussed. CFD models that reproduce flow statistics would be most appropriate for this purpose since it could be expected that they will more realistically represent the environment. However, since concentration-peaks in the ever-present spatiotemporal fluctuations of airborne chemicals contribute so much to the toxic load, it is shown that straight-forward direct linking of a CFD model to a toxic load model is not a suitable approach for predicting consequences of a toxic release. Furthermore, it is demonstrated that the use of different turbulence models leads to different casualty assessments. Obviously, there is an urgent need to establish widely accepted methods, ideally with known uncertainty measures. Thus, further research in this area is of great importance.

  • 19. Carlsen, Hanne Krage
    et al.
    Back, Erik
    Eneroth, Kristina
    Gislason, Thorarinn
    Holm, Mathias
    Janson, Christer
    Jensen, Steen Solvang
    Johannessen, Ane
    Kaasik, Marko
    Modig, Lars
    Segersson, David
    SMHI, Research Department, Air quality.
    Sigsgaard, Torben
    Forsberg, Bertil
    Olsson, David
    Orru, Hans
    Indicators of residential traffic exposure: Modelled NOX, traffic proximity, and self-reported exposure in RHINE III2017In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 167, p. 416-425Article in journal (Refereed)
  • 20.
    Carlsen, Hanne Krage
    et al.
    Umea Univ, Dept Publ Hlth & Clin Med, Occupat & Environm Med, Umea, Sweden.;Univ Iceland, Engn & Nat Sci, Reykjavik, Iceland.;Univ Gothenburg, Inst Med, Sect Occupat & Environm Med, Dept Publ Hlth & Community Med,Sahlgrenska Acad, Gothenburg, Sweden..
    Bäck, Erik
    Environm Adm, Gothenburg, Sweden..
    Eneroth, Kristina
    Environm & Hlth Adm, Stockholm, Sweden..
    Gislason, Thorarinn
    Univ Iceland, Fac Med, Reykjavik, Iceland.;Landspitali Natl Univ Hosp Iceland, Dept Resp Med & Sleep, Reykjavik, Iceland..
    Holm, Mathias
    Univ Gothenburg, Inst Med, Sect Occupat & Environm Med, Dept Publ Hlth & Community Med,Sahlgrenska Acad, Gothenburg, Sweden..
    Janson, Christer
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Lung- allergy- and sleep research.
    Jensen, Steen Solvang
    Aarhus Univ, Dept Environm Sci, Roskilde, Denmark..
    Johannessen, Ane
    Univ Bergen, Dept Global Publ Hlth & Primary Care, Bergen, Norway..
    Kaasik, Marko
    Univ Tartu, Inst Phys, Tartu, Estonia..
    Modig, Lars
    Umea Univ, Div Occupat & Environm Med, Dept Publ Hlth & Clin Med, Umed, Sweden..
    Segersson, David
    Swedish Meteorol & Hydrol Inst, Norrkoping, Sweden..
    Sigsgaard, Torben
    Aarhus Univ, Dept Publ Hlth, Aarhus, Denmark..
    Forsberg, Bertil
    Umea Univ, Dept Publ Hlth & Clin Med, Occupat & Environm Med, Umea, Sweden..
    Olsson, David
    Umea Univ, Dept Publ Hlth & Clin Med, Occupat & Environm Med, Umea, Sweden..
    Orru, Hans
    Umea Univ, Dept Publ Hlth & Clin Med, Occupat & Environm Med, Umea, Sweden.;Univ Tartu, Dept Family Med & Publ Hlth, Tartu, Estonia..
    Indicators of residential traffic exposure: Modelled NOX, traffic proximity, and self-reported exposure in RHINE III2017In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 167, p. 416-425Article in journal (Refereed)
    Abstract [en]

    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, Ulna 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 mu g/m(3); 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.

  • 21. Carmichael, G R
    et al.
    Calori, G
    Hayami, H
    Uno, I
    Cho, S Y
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Kim, S B
    Ichikawa, Y
    Ikeda, Y
    Woo, J H
    Ueda, H
    Amann, M
    The MICS-Asia study: model intercomparison of long-range transport and sulfur deposition in East Asia2002In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 36, no 2, p. 175-199Article in journal (Refereed)
    Abstract [en]

    An intercomparison study involving eight long-range transport models for sulfur deposition in East Asia has been initiated, The participating models included Eulerian and Lagrangian frameworks, with a wide variety of vertical resolutions and numerical approaches. Results from this study, in which models used common data sets for emissions, meteorology, and dry, wet and chemical conversion rates, are reported and discussed. Model results for sulfur dioxide and sulfate concentrations, wet deposition amounts, for the period January and May 1993, are compared with observed quantities at 18 surface sites in East Asia. At many sites the ensemble of models is found to have high skill in predicting observed quantities. At other sites all models show poor predictive capabilities. Source-receptor relationships estimated by the models are also compared. The models show a high degree of consistency in identifying the main source-receptor relationships, as well as in the relative contributions of wet/dry pathways for removal. But at some locations estimated deposition amounts can vary by a factor or 5. The influence of model structure and parameters on model performance is discussed. The main factors determining the deposition fields are the emissions and underlying meteorological fields. Model structure in terms of vertical resolution is found to be more important than the parameterizations used for chemical conversion and removal, as these processes are highly coupled and often work in compensating directions. (C) 2002 Elsevier Science Ltd. All rights reserved.

  • 22. Carmichael, G. R.
    et al.
    Sakurai, T.
    Streets, D.
    Hozumi, Y.
    Ueda, H.
    Park, S. U.
    Fung, C.
    Han, Z.
    Kajino, M.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Bennet, Cecilia
    SMHI, Research Department, Air quality.
    Hayami, H.
    Sartelet, K.
    Holloway, T.
    Wang, Z.
    Kannari, A.
    Fu, J.
    Matsuda, K.
    Thongbooncho, N.
    Amann, M.
    MICS-Asia II: The model intercomparison study for Asia Phase II methodology and overview of findings2008In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 42, no 15, p. 3468-3490Article, review/survey (Refereed)
    Abstract [en]

    Results from the Model Intercomparison Study Asia Phase II (MICS-Asia II) are presented. Nine different regional modeling groups simulated chemistry and transport of ozone (O-3), secondary aerosol, acid deposition, and associated precursors, using common emissions and boundary conditions derived from a global model. Four-month-long periods, representing 2 years and three seasons (i.e., March, July, and December in 2001, and March in 2002), are analyzed. New observational data, obtained under the EANET (the Acid Deposition Monitoring Network in East Asia) monitoring program, were made available for this study, and these data provide a regional database to compare with model simulations. The analysis focused around seven subject areas: O-3 and related precursors, aerosols, acid deposition, global inflow of pollutants and precursor to Asia, model sensitivities to aerosol parameterization, analysis of emission fields, and detailed analyses of individual models, each of which is presented in a companion paper in this issue of Atmospheric Environment. This overview discusses the major findings of the study, as well as information on common emissions, meteorological conditions, and observations. (C) 2007 Elsevier Ltd. All rights reserved.

  • 23. Carslaw, N
    et al.
    Langer, S
    YKI – Ytkemiska institutet.
    Wolkoff, P
    New Directions: Where is the link between reactive indoor air chemistry and health effects?2009In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 43, no 24, p. 3808-3809Article in journal (Refereed)
  • 24. Cavalli, F.
    et al.
    Alastuey, A.
    Areskoug, Hans
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ceburnis, D.
    Cech, J.
    Genberg, J.
    Harrison, R. M.
    Jaffrezo, J. L.
    Kiss, G.
    Laj, P.
    Mihalopoulos, N.
    Perez, N.
    Quincey, P.
    Schwarz, J.
    Sellegri, K.
    Spindler, G.
    Swietlicki, E.
    Theodosi, C.
    Yttri, K. E.
    Aas, W.
    Putaud, J. P.
    A European aerosol phenomenology-4: Harmonized concentrations of carbonaceous aerosol at 10 regional background sites across Europe2016In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 144, p. 133-145Article in journal (Refereed)
    Abstract [en]

    Although particulate organic and elemental carbon (OC and EC) are important constituents of the suspended atmospheric particulate matter (PM), measurements of OC and EC are much less common and More uncertain than measurements of e.g. the ionic components of PM. In the framework of atmospheric research infrastructures supported by the European Union, actions have been undertaken to determine and mitigate sampling artefacts, and assess the comparability of OC and EC data obtained in a network of 10 atmospheric observatories across Europe. Positive sampling artefacts (from 0:4 to 2.8 mu g C/m(3)) and analytical discrepancies (between -50% and +40% for the EC/TC ratio) have been taken into account to generate a robust data set, from which we established the phenomenology of carbonaceous aerosols at regional background sites in Europe. Across the network, TC and EC annual average concentrations range from 0.4 to 9 mu g C/m(3), and from 0.1 to 2 mu g C/m(3), respectively. TC/PM10 annual mean ratios range from 0.11 at a Mediterranean site to 0.34 at the most polluted continental site, and TC/PM2.5 ratios are slightly greater at all sites (0.15-0.42). EC/TC annual mean ratios range from 0.10 to 0.22, and do not depend much on PM concentration levels, especially in winter. Seasonal variations in PM and TC concentrations, and in TC/PM and EC/TC ratios, differ across the network, which can be explained by seasonal changes in PM source contributions at some sites.

  • 25.
    Cehlin, Mathias
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Computed Tomography for Gas Sensing Indoors Using a Modified Low Third Derivative Method: Numerical Study2006In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844Article in journal (Other academic)
  • 26. Cho, Chaeyoon
    et al.
    Kim, Sang-Woo
    Lee, Meehye
    Lim, Saehee
    Fang, Wenzheng
    Gustafsson, Örjan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Andersson, August
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Park, Rokjin J.
    Sheridan, Patrick J.
    Observation-based estimates of the mass absorption cross-section of black and brown carbon and their contribution to aerosol light absorption in East Asia2019In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 212, p. 65-74Article in journal (Refereed)
    Abstract [en]

    In this study, we estimated the contribution of black carbon (BC) and brown carbon (BrC) to aerosol light absorption from surface in-situ and aerosol robotic network (AERONET) columnar observations. The mass absorption cross-section (MAC) of BC (MAC(BC)) was estimated to be 6.4 +/- 1.5 m(2) g(-1) at 565 mn from in-situ aerosol measurements at Gosan Climate Observatory (GCO), Korea, in January 2014, which was lower than those observed in polluted urban areas. A BrC MAC of 0.62 +/- 0.06 m(2) g(-1) (565 mn) in our estimate is approximately ten times lower than MACK at 565 nm. The contribution of BC and BrC to the carbonaceous aerosol absorption coefficient at 565 nm from the in-situ measurements was estimated at 88.1 +/- 7.4% and 11.9 +/- 7.4%, respectively at GCO. Similarly, the contribution of BC and BrC to the absorption aerosol optical depth (AAOD) for carbonaceous aerosol (CA), constrained by AERONET observations at 14 sites over East Asia by using different spectral dependences of the absorption (i.e., absorption Angstrom exponent) of BC and BrC, was 84.9 +/- 2.8% and 15.1 +/- 2.8% at 565 nm, respectively. The contribution of BC to CA AAOD was greater in urban sites than in the background areas, whereas the contribution of BrC to CA AAOD was higher in background sites. The overall contribution of BC to CA AAOD decreased by 73%-87% at 365 nm, and increased to 93%-97% at 860 nm. The contribution of BrC to CA AAOD decreased significantly with increasing wavelength from approximately 17% at 365 nm to 4% at 860 nm.

  • 27. Cirino, Glauber
    et al.
    Brito, Joel
    Barbosa, Henrique M. J.
    Rizzo, Luciana V.
    Tunved, Peter
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    de Sá, Suzane S.
    Jimenez, Jose L.
    Palm, Brett B.
    Carbone, Samara
    Lavric, Jost V.
    Souza, Rodrigo A. F.
    Wolff, Stefan
    Walter, David
    Tota, Júlio
    Oliveira, Maria B. L.
    Martin, Scot T.
    Artaxo, Paulo
    Observations of Manaus urban plume evolution and interaction with biogenic emissions in GoAmazon 2014/52018In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 191, p. 513-524Article in journal (Refereed)
    Abstract [en]

    As part of the Observations and Modeling of the Green Ocean Amazon (GoAmazon 2014/5) Experiment, detailed aerosol and trace gas measurements were conducted near Manaus, a metropolis located in the central Amazon Basin. Measurements of aerosol particles and trace gases were done downwind Manaus at the sites T2 (Tiwa Hotel) and T3 (Manacapuru), at a distance of 8 and 70 km from Manaus, respectively. Based on in-plume measurements closer to Manaus (site T2), the chemical signatures of city emissions were used to improve the interpretation of pollutant levels at the T3 site. We derived chemical and physical properties for the city's atmospheric emission ensemble, taking into account only air masses impacted by the Manaus plume at both sites, during the wet and dry season Intensive Operating Periods (IOPs). At T2, average concentrations of aerosol number (CN), CO and SO2 were 5500 cm(-3) (between 10 and 490 nm), 145 ppb and 0.60 ppb, respectively, with a typical ratio ACN/ACO of 60-130 particles cm(-3) ppb(-1). The aerosol scattering (at RH < 60%) and absorption at 637 nm at T2 ranged from 10 to 50 M m(-1) and 5-10 M m(-1), respectively, leading to a mean single scattering albedo (SSA) of 0.70. In addition to identifying periods dominated by Manaus emissions at both T2 and T3, the plume transport between the two sampling sites was studied using back trajectory calculations. Results show that the presence of the Manaus plume at site T3 was important mainly during the daytime and at the end of the afternoons. During time periods directly impacted by Manaus emissions, an average aerosol number concentration of 3200 cm(-3) was measured at T3. Analysis of plume evolution between T2 and T3 indicates a transport time of 4-5 h. Changes of submicron organic and sulfate aerosols ratios relative to CO (Delta OA/Delta CO and Delta SO4/Delta CO, respectively) indicate significant production of secondary organic aerosol (SOA), corresponding to a 40% mass increase in OA and a 30% in SO4 mass concentration. Similarly, during air mass arrival at T3 the SSA increased to 0.83 from 0.70 at T2, mainly associated with an increase in organic aerosol concentration. Aerosol particle size distributions show a strong decrease in the Aitken nuclei mode (10-100 nm) during the transport from T2 to T3, in particular above 30 nm, as a result of efficient coagulation processes into larger particles. A decrease of 30% in the particle number concentration and an increase of about 50 nm in geometric mean diameter were observed from T2 to T3 sites. The study of the evolution of aerosol properties downwind of the city of Manaus improves our understanding of how coupling of anthropogenic and biogenic sources may be impacting the sensitive Amazonian atmosphere.

  • 28. Cyrys, Josef
    et al.
    Eeftens, Marloes
    Heinrich, Joachim
    Ampe, Christophe
    Armengaud, Alexandre
    Beelen, Rob
    Bellander, Tom
    Beregszaszi, Timea
    Birk, Matthias
    Cesaroni, Giulia
    Cirach, Marta
    de Hoogh, Kees
    De Nazelle, Audrey
    de Vocht, Frank
    Declercq, Christophe
    Dėdelė, Audrius
    Dimakopoulou, Konstantina
    Eriksen, Kirsten
    Galassi, Claudia
    Gra˛ulevičienėo, Regina
    Grivas, Georgios
    Gruzieva, Olena
    Hagenbjörk Gustafsson, Annika
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hoffmann, Barbara
    Iakovides, Minas
    Ineichen, Alex
    Krämer, Ursula
    Lanki, Timo
    Lozano, Patricia
    Madsena, Christian
    Meliefste, Kees
    Modig, Lars
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Mölter, Anna
    Mosler, Gioia
    Nieuwenhuijsen, Mark
    Nonnemachera, Michael
    Oldenwening, Marieke
    Peters, Annette
    Ponteta, Sabrina
    Probst-Hensch, Nicole
    Quassa, Ulrich
    Raaschou-Nielsen, Ole
    Ranzia, Andrea
    Sugiri, Dorothee
    Stephanou, Euripides G.
    Taimisto, Pekka
    Tsai, Ming-Yi
    Vaskövi, Éva
    Villania, Simona
    Wang, Meng
    Brunekreef, Bert
    Hoek, Gerard
    Variation of NO2 and NOx concentrations between and within 36 European study areas: Results from the ESCAPE study2012In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 62, p. 374-390Article in journal (Refereed)
    Abstract [en]

    The ESCAPE study (European Study of Cohorts for Air Pollution Effects) investigates long-term effects of exposure to air pollution on human health in Europe. This paper documents the spatial variation of measured NO2 and NOx concentrations between and within 36 ESCAPE study areas across Europe.

    In all study areas NO2 and NOx were measured using standardized methods between October 2008 and April 2011. On average, 41 sites were selected per study area, including regional and urban background as well as street sites. The measurements were conducted in three different seasons, using Ogawa badges. Average concentrations for each site were calculated after adjustment for temporal variation using data obtained from a routine monitor background site.

    Substantial spatial variability was found in NO2 and NOx concentrations between and within study areas; 40% of the overall NO2 variance was attributable to the variability between study areas and 60% to variability within study areas. The corresponding values for NOx were 30% and 70%. The within-area spatial variability was mostly determined by differences between street and urban background concentrations. The street/urban background concentration ratio for NO2 varied between 1.09 and 3.16 across areas. The highest median concentrations were observed in Southern Europe, the lowest in Northern Europe.

    In conclusion, we found significant contrasts in annual average NO2 and NOx concentrations between and especially within 36 study areas across Europe. Epidemiological long-term studies should therefore consider different approaches for better characterization of the intra-urban contrasts, either by increasing of the number of monitors or by modelling.

  • 29.
    Córdoba-Jabonero, Carmen
    et al.
    Instituto Nacional de Técnica Aeroespacial (INTA), Área de Investigación e Instrumentación Atmosférica, Madrid, Spain.
    Sicard, Michaël
    CommSensLab, Dept. of Signal Theory and Communications, Universitat Politècnica de Catalunya (UPC), Barcelona, Spain. Ciències i Tecnologies de l'Espai-Centre de Recerca de l'Aeronàutica i de l'Espai/Institut d'Estudis Espacials de Catalunya (CTE-CRAE/IEEC), Universitat Politècnica de Catalunya (UPC), Barcelona, Spain.
    Del Águila, Ana
    nstituto Nacional de Técnica Aeroespacial (INTA), Área de Investigación e Instrumentación Atmosférica, Madrid, Spain. emote Sensing Technology Institute, German Aerospace Centre (DLR), Oberpfaffenhofen, Germany.
    Jiménez, Marcos
    Instituto Nacional de Técnica Aeroespacial (INTA), Área de Sistemas de Teledetección, Madrid, Spain.
    Zorzano, María-Paz
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Centro de Astrobiología (CSIC-INTA), Madrid, Spain.
    Performance of a dust model to predict the vertical mass concentration of an extreme Saharan dust event in the Iberian Peninsula: Comparison with continuous, elastic, polarization-sensitive lidars2019In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 214, article id 116828Article in journal (Refereed)
    Abstract [en]

    An intense dusty event unusually occurred in wintertime over the Iberian Peninsula was detected over two Spanish NASA/MPLNET sites: the temporary Torrejón Observational Tower for Environmental Monitoring (TOTEM, 40.5°N 3.5°W) and the Barcelona station (BCN, 41.4°N 2.1°E). The highest dust incidence was observed from 22 to 23 February 2017; this two-day dusty scenario is examined in order to evaluate the performance of the operational NMMB/BSC-Dust model on forecasted mass concentration profiling in comparison with polarized Micro-Pulse (P-MPL) mass estimates for dust particles. First, the optical properties of the dust (DD) were effectively separated from the non-dust (ND) component by using the combined P-MPL/POLIPHON method. Lidar-derived DD optical depths reached maximums of 1.6–1.7 (±0.1) at both stations. Typical features for dust were obtained: linear particle depolarization ratios between 0.3 and 0.4, and lidar ratios in the range of 41–70 sr and 36–66 sr, respectively, for TOTEM and BCN. Lower AERONET Ångström exponents were reported for TOTEM (0.12 ± 0.04) than at BCN (0.5 ± 0.3). HYSPLIT back-trajectory analysis showed air masses coming from the Sahara region, mostly transporting dust particles. AERONET-derived Mass Extinction Efficiencies (MEE) under dusty conditions were used for the extinction-to-mass conversion procedure as applied to the P-MPL measurements: MEE values were lower at TOTEM (0.57 ± 0.01 m2 g−1) than those found at BCN (0.87 ± 0.10 m2 g−1). Those results reveal that dust particles were predominantly larger at TOTEM than those observed at BCN, and a longer transport of dust particles from the Sahara sources to BCN could favour a higher gravitational settling of coarser particles before reaching BCN than TOTEM. A comparative analysis between profiles as obtained from the lidar DD component of the mass concentration and those forecasted by the NMMB/BSC-Dust model (25 available dusty profiles) was performed. The degree of agreement between both datasets was determined by the percentage of dusty cases satisfying selected model performance criteria (favourable cases) of two proxies: the Mean Fractional Bias, M&#x2062;F&#x2062;B" role="presentation" style="box-sizing: border-box; margin: 0px; padding: 0px; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative;">MFBM⁢F⁢B, and the correlation coefficient, C&#x2062;C" role="presentation" style="box-sizing: border-box; margin: 0px; padding: 0px; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative;">CCC⁢C. A good agreement is found (72% and 76%, respectively, of favourable cases); however, large discrepancies are found at low altitudes between the dust model and the lidar observations, mostly at early stages of the arrival of the dust intrusion. Higher model-derived centre-of-mass (CoM) heights are found in 60% of the cases (with differences < 15% w.r.t. the lidar CoM, whose values ranged between 1.8 and 2.3 km height). In addition, modelled mass loading (ML) values were generally higher than the lidar-derived ones. However, the evolution of the mass loading along the two days, 22 and 23 February, was rather similar for both the model forecasting and lidar observations at both stations. The relative ML differences (<50%) of the mass loading represented 60% of all cases. Discrepancies can be based on the uncertainties in the lidar retrievals (mainly, the use of single extinction-to-mass conversion factors). In general, a moderately good agreement is observed between the P-MPL-derived dust mass concentration profiles and the NMMB/BSC-Dust model ones at both sites; large discrepancies are found at lower altitudes, plausibly due to a lower sedimentation of dust particles coming from upper layers by gravitational settling than that introduced by the NMMB/BSC-Dust model in the simulations. The methodology described for the dust model evaluation against the continuous P-MPL observations can be easily adopted for an operational use of the NMMB/BSC-Dust model for forecasting the mass concentration profiling in frequently dust-affected regions with serious climate and environmental implications, as long as a typical MEE for dust could be accurately specified. Hence, a statistical analysis for determining AERONET-based MEE values over the Iberian Peninsula is on-going.

  • 30. Dahl, Andreas
    et al.
    Gharibi, Arash
    Swietlicki, Erik
    Gudmundsson, Anders
    Bohgard, Mats
    Ljungman, Anders
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Occupational and Environmental Medicine.
    Blomqvist, Göran
    Gustafsson, Mats
    Traffic-generated emissions of ultrafine particles from pavement-tire interface2006In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 40, no 7, p. 1314-1323Article in journal (Refereed)
    Abstract [en]

    In a road simulator study, a significant source of sub-micrometer fine particles produced by the road-tire interface was observed. Since the particle size distribution and source strength is dependent on the type of tire used, it is likely that these particles largely originate from the tires, and not the road pavement. The particles consisted most likely of mineral oils from the softening filler and fragments of the carbon-reinforcing filler material (soot agglomerates). This identification was based on transmission electron microscopy studies of collected ultrafine wear particles and on-line thermal treatment using a thermodesorber. The mean particle number diameters were between 15-50 nm, similar to those found in light duty vehicle (LDV) tail-pipe exhaust. A simple box model approach was used to estimate emission factors in the size interval 15-700 nm. The emission factors increased with increasing vehicle speed, and varied between 3.7×1011 and 3.2×10 12 particles vehicle-1 km-1 at speeds of 50 and 70 km h-1. This corresponds to between 0.1-1% of tail-pipe emissions in real-world emission studies at similar speeds from a fleet of LDV with 95% gasoline and 5% diesel-fueled cars. The emission factors for particles originating from the road-tire interface were, however, similar in magnitude to particle number emission factors from liquefied petroleum gas-powered vehicles derived in test bench studies in Australia 2005. Thus the road-tire interface may be a significant contributor to particle emissions from ultraclean vehicles. © 2005 Elsevier Ltd. All rights reserved.

  • 31.
    Dahl, Andreas
    et al.
    Lund University, Div Ergonom & Aerosol Technology.
    Gharibi, Arash
    Division of Nuclear Physics, Lund University.
    Swietlicki, Erik
    Division of Nuclear Physics, Lund University.
    Gudmundsson, Anders
    Division of Ergonomics and Aerosol Technology, Lund University.
    Bohgard, Mats
    Division of Ergonomics and Aerosol Technology, Lund University.
    Ljungman, Anders
    Faculty of Health Sciences, Linköping University.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Enviroment and traffic analysis.
    Gustafsson, Mats
    Swedish National Road and Transport Research Institute, Society, environment and transport, Enviroment and traffic analysis.
    Traffic-generated emissions of ultrafine particles from pavement-tire interface2006In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 40, no 7, p. 1314-1323Article in journal (Refereed)
    Abstract [en]

    In a road simulator study, a significant source of sub-micrometer fine particles produced by the road-tire interface was observed. Since the particle size distribution and source strength is dependent on the type of tire used, it is likely that these particles largely originate from the tires, and not the road pavement. The particles consisted most likely of mineral oils from the softening filler and fragments of the carbon-reinforcing filler material (soot agglomerates). This identification was based on transmission electron microscopy studies of collected ultrafine wear particles and on-line thermal treatment using a thermodesorber. The mean particle number diameters were between 15-50 nm, similar to those found in light duty vehicle (LDV) tail-pipe exhaust. A simple box model approach was used to estimate emission factors in the size interval 15-700 nm. The emission factors increased with increasing vehicle speed, and varied between 3.7 x 10(11) and 3.2 x 10(12) particles vehicle(-1) km(-1) at speeds of 50 and 70 km h(-1). This corresponds to between 0.1-1% of tail-pipe emissions in real-world emission studies at similar speeds from a fleet of LDV with 95% gasoline and 5% diesel-fueled cars. The emission factors for particles originating from the road-tire interface were, however, similar in magnitude to particle number emission factors from liquefied petroleum gas-powered vehicles derived in test bench studies in Australia 2005. Thus the road-tire interface may be a significant contributor to particle emissions from ultraclean vehicles. (c) 2005 Elsevier Ltd. All rights reserved.

  • 32.
    Degrendele, Céline
    et al.
    RECETOX (Research Centre for Toxic Compounds in the Environment), Faculty of Science, Masaryk University, Brno, Czech Republic.
    Okonski, Krzysztof
    RECETOX (Research Centre for Toxic Compounds in the Environment), Faculty of Science, Masaryk University, Brno, Czech Republic.
    Melymuk, Lisa
    RECETOX (Research Centre for Toxic Compounds in the Environment), Faculty of Science, Masaryk University, Brno, Czech Republic.
    Landlová, Linda
    RECETOX (Research Centre for Toxic Compounds in the Environment), Faculty of Science, Masaryk University, Brno, Czech Republic.
    Kukucka, Petr
    RECETOX (Research Centre for Toxic Compounds in the Environment), Faculty of Science, Masaryk University, Brno, Czech Republic.
    Cupr, Pavel
    RECETOX (Research Centre for Toxic Compounds in the Environment), Faculty of Science, Masaryk University, Brno, Czech Republic.
    Klánová, Jana
    RECETOX (Research Centre for Toxic Compounds in the Environment), Faculty of Science, Masaryk University, Brno, Czech Republic.
    Size specific distribution of the atmospheric particulate PCDD/Fs, dl-PCBs and PAHs on a seasonal scale: Implications for cancer risks from inhalation2014In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 98, p. 410-416Article in journal (Refereed)
    Abstract [en]

    This study presents the seasonal size distribution of particulate polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in the atmosphere. Particles were sampled from October 2009 to October 2010 on a seasonal basis using a cascade impactor collecting six size fractions at a rural and urban site in the Brno area, Czech Republic. Higher concentrations of PAHs, PCDD/Fs and dl-PCBs were observed in cold seasons at both sites, attributed to the seasonality of the gas-particle partitioning, the increase of emissions and the lower boundary mixing layer in winter. All of the compounds showed a strong accumulation in the fine fraction, with, on average, 71% of Sigma PAHs, 73% of Sigma PCDD/Fs and 60% of Sigma dl-PCBs associated with particles <0.95 mu m. The human risk assessment via inhalation was addressed and followed the same pattern as for concentrations, with 41 and 7 times higher risk in winter compared to summer at the rural and urban sites, respectively. More than 70% of cancer risks of PAHs, PCDD/Fs and dl-PCBs was associated with particles <0.95 mu m. Moreover, an overestimation of the cancer risk via inhalation of up to 50% occurred when the size distribution of related compounds was not considered.

  • 33. Denby, B. R.
    et al.
    Ketzel, M.
    Ellermann, T.
    Stojiljkovic, A.
    Kupiainen, K.
    Niemi, J. V.
    Norman, M.
    Johansson, Christer
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Environment and Health Protection Administration of the City of Stockholm, Sweden.
    Gustafsson, M.
    Blomqvist, G.
    Janhall, S.
    Sundvor, I.
    Road salt emissions: A comparison of measurements and modelling using the NORTRIP road dust emission model2016In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 141, p. 508-522Article in journal (Refereed)
    Abstract [en]

    De-icing of road surfaces is necessary in many countries during winter to improve vehicle traction. Large amounts of salt, most often sodium chloride, are applied every year. Most of this salt is removed through drainage or traffic spray processes but a certain amount may be suspended, after drying of the road surface, into the air and will contribute to the concentration of particulate matter. Though some measurements of salt concentrations are available near roads, the link between road maintenance salting activities and observed concentrations of salt in ambient air is yet to be quantified. In this study the NORTRIP road dust emission model, which estimates the emissions of both dust and salt from the road surface, is applied at five sites in four Nordic countries for ten separate winter periods where daily mean ambient air measurements of salt concentrations are available. The model is capable of reproducing many of the salt emission episodes, both in time and intensity, but also fails on other occasions. The observed mean concentration of salt in PM10, over all ten datasets, is 4.2 mu g/m(3) and the modelled mean is 2.8 mu g/m(3), giving a fractional bias of -0.38. The RMSE of the mean concentrations, over all 10 datasets, is 2.9 mu g/m(3) with an average R-2 of 0.28. The mean concentration of salt is similar to the mean exhaust contribution during the winter periods of 2.6 mu g/m(3). The contribution of salt to the kerbside winter mean PM10 concentration is estimated to increase by 4.1 +/- 3.4 mu g/m(3) for every kg/m(2) of salt applied on the road surface during the winter season. Additional sensitivity studies showed that the accurate logging of salt applications is a prerequisite for predicting salt emissions, as well as good quality data on precipitation. It also highlights the need for more simultaneous measurements of salt loading together with ambient air concentrations to help improve model parameterisations of salt and moisture removal processes.

  • 34. Denby, B. R.
    et al.
    Sundvor, I.
    Johansson, C.
    Pirjola, L.
    Ketzel, M.
    Norman, M.
    Kupiainen, K.
    Gustafsson, M.
    Blomqvist, G.
    Kauhaniemi, M.
    Omstedt, Gunnar
    SMHI, Research Department, Air quality.
    A coupled road dust and surface moisture model to predict non-exhaust road traffic induced particle emissions (NORTRIP). Part 2: Surface moisture and salt impact modelling2013In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 81, p. 485-503Article in journal (Refereed)
    Abstract [en]

    Non-exhaust traffic induced emissions are a major source of airborne particulate matter in most European countries. This is particularly important in Nordic and Alpine countries where winter time road traction maintenance occurs, e.g. salting and sanding, and where studded tyres are used. Though the total mass generated by wear sources is a key factor in non-exhaust emissions, these emissions are also strongly controlled by surface moisture conditions. In this paper, Part 2, the road surface moisture submodel of a coupled road dust and surface moisture model (NORTRIP) is described. We present a description of the road surface moisture part of the model and apply the coupled model to seven sites in Stockholm, Oslo, Helsinki and Copenhagen over 18 separate periods, ranging from 3.5 to 24 months. At two sites surface moisture measurements are available and the moisture sub-model is compared directly to these observations. The model predicts the frequency of wet roads well at both sites, with an average fractional bias of -2.6%. The model is found to correctly predict the hourly surface state, wet or dry, 85% of the time. From the 18 periods modelled using the coupled model an average absolute fractional bias of 15% for PM10 concentrations was found. Similarly the model predicts the 90'th daily mean percentiles of PMio with an average absolute bias of 19% and an average correlation (R-2) of 0.49. When surface moisture is not included in the modelling then this average correlation is reduced to 0.16, demonstrating the importance of the surface moisture conditions. Tests have been carried out to assess the sensitivity of the model to model parameters and input data. The model provides a useful tool for air quality management and for improving our understanding of non-exhaust traffic emissions. (C) 2013 The Authors. Published by Elsevier Ltd. All rights reserved.

  • 35. Denby, B. R.
    et al.
    Sundvor, I.
    Johansson, C.
    Pirjola, L.
    Ketzel, M.
    Norman, M.
    Kupiainen, K.
    Gustafsson, M.
    Blomqvist, G.
    Omstedt, Gunnar
    SMHI, Research Department, Air quality.
    A coupled road dust and surface moisture model to predict non-exhaust road traffic induced particle emissions (NORTRIP). Part 1: Road dust loading and suspension modelling2013In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 77, p. 283-300Article in journal (Refereed)
    Abstract [en]

    Non-exhaust traffic induced emissions are a major source of particle mass in most European countries. This is particularly important in Nordic and Alpine countries where winter time road traction maintenance occurs, e.g. salting and sanding, and where studded tyres are used. In this paper, Part 1, the road dust sub-model of a coupled road dust and surface moisture model (NORTRIP) is described. The model provides a generalised process based formulation of the non-exhaust emissions, with emphasis on the contribution of road wear, suspension, surface dust loading and the effect of road surface moisture (retention of wear particles and suspended emissions). The model is intended for use as a tool for air quality managers to help study the impact of mitigation measures and policies. We present a description of the road dust sub-model and apply the model to two sites in Stockholm and Copenhagen where seven years of data with surface moisture measurements are available. For the site in Stockholm, where studded tyres are in use, the model predicts the PM10 concentrations very well with correlations (R-2) in the range of R-2 = 0.76-0.91 for daily mean PM10. The model also reproduces well the impact of a reduction in studded tyres at this site. For the site in Copenhagen the correlation is lower, in the range 0.44-0.51. The addition of salt is described in the model and at both sites this leads to improved correlations due to additional salt emissions. For future use of the model a number of model parameters, e.g. wear factors and suspension rates, still need to be refined. The effect of sanding on PM10 emissions is also presented but more information will be required before this can be confidently applied for management applications. (C) 2013 Elsevier Ltd. All rights reserved.

  • 36. Denby, B. R.
    et al.
    Sundvor, I.
    Johansson, Christer
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Pirjola, L.
    Ketzel, M.
    Norman, M.
    Kupiainen, K.
    Gustafsson, M.
    Blomqvist, G.
    Kauhaniemi, M.
    Omstedt, G.
    A coupled road dust and surface moisture model to predict non-exhaust road traffic induced particle emissions (NORTRIP). Part 2: Surface moisture and salt impact modelling2013In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 81, p. 485-503Article in journal (Refereed)
    Abstract [en]

    Non-exhaust traffic induced emissions are a major source of airborne particulate matter in most European countries. This is particularly important in Nordic and Alpine countries where winter time road traction maintenance occurs, e.g. salting and sanding, and where studded tyres are used. Though the total mass generated by wear sources is a key factor in non-exhaust emissions, these emissions are also strongly controlled by surface moisture conditions. In this paper, Part 2, the road surface moisture sub-model of a coupled road dust and surface moisture model (NORTRIP) is described. We present a description of the road surface moisture part of the model and apply the coupled model to seven sites in Stockholm, Oslo, Helsinki and Copenhagen over 18 separate periods, ranging from 3.5 to 24 months. At two sites surface moisture measurements are available and the moisture sub-model is compared directly to these observations. The model predicts the frequency of wet roads well at both sites, with an average fractional bias of −2.6%. The model is found to correctly predict the hourly surface state, wet or dry, 85% of the time. From the 18 periods modelled using the coupled model an average absolute fractional bias of 15% for PM10 concentrations was found. Similarly the model predicts the 90'th daily mean percentiles of PM10 with an average absolute bias of 19% and an average correlation (R2) of 0.49. When surface moisture is not included in the modelling then this average correlation is reduced to 0.16, demonstrating the importance of the surface moisture conditions. Tests have been carried out to assess the sensitivity of the model to model parameters and input data. The model provides a useful tool for air quality management and for improving our understanding of non-exhaust traffic emissions.

  • 37. Denby, B. R.
    et al.
    Sundvor, I.
    Johansson, Christer
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Pirjola, L.
    Ketzel, M.
    Norman, M.
    Kupiainen, K.
    Gustafsson, M.
    Blomqvist, G.
    Omstedt, G.
    A coupled road dust and surface moisture model to predict non-exhaust road traffic induced particle emissions (NORTRIP). Part 1: Road dust loading and suspension modelling2013In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 77, p. 283-300Article in journal (Refereed)
    Abstract [en]

    Non-exhaust traffic induced emissions are a major source of particle mass in most European countries. This is particularly important in Nordic and Alpine countries where winter time road traction maintenance occurs, e.g. salting and sanding, and where studded tyres are used. In this paper, Part 1, the road dust sub-model of a coupled road dust and surface moisture model (NORTRIP) is described. The model provides a generalised process based formulation of the non-exhaust emissions, with emphasis on the contribution of road wear, suspension, surface dust loading and the effect of road surface moisture (retention of wear particles and suspended emissions). The model is intended for use as a tool for air quality managers to help study the impact of mitigation measures and policies. We present a description of the road dust sub-model and apply the model to two sites in Stockholm and Copenhagen where seven years of data with surface moisture measurements are available. For the site in Stockholm, where studded tyres are in use, the model predicts the PM10 concentrations very well with correlations (R-2) in the range of R-2 = 0.76-0.91 for daily mean PM10. The model also reproduces well the impact of a reduction in studded tyres at this site. For the site in Copenhagen the correlation is lower, in the range 0.44-0.51. The addition of salt is described in the model and at both sites this leads to improved correlations due to additional salt emissions. For future use of the model a number of model parameters, e.g. wear factors and suspension rates, still need to be refined. The effect of sanding on PM10 emissions is also presented but more information will be required before this can be confidently applied for management applications.

  • 38.
    Denby, Bruce R.
    et al.
    The Norwegian Meteorological Institute (MET).
    Ketzel, M.
    Aarhus University.
    Ellermann, T.
    Aarhus University.
    Stojiljkovic, A.
    Nordic Envicon Oy.
    Kupiainen, K.
    Nordic Envicon Oy.
    Niemi, J. V.
    Helsinki Region Environmental Services Authority (HSY).
    Norman, M.
    Environment and Health Protection Administration of the City of Stockholm.
    Johansson, C.
    Stockholm University,.
    Gustafsson, Mats
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Janhäll, Sara
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Sundvor, I.
    The Norwegian Institute for Air Research (NILU).
    Road salt emissions: A comparison of measurements and modelling using the NORTRIP road dust emission model2016In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 141, p. 508-522Article in journal (Refereed)
    Abstract [en]

    De-icing of road surfaces is necessary in many countries during winter to improve vehicle traction. Large amounts of salt, most often sodium chloride, are applied every year. Most of this salt is removed through drainage or traffic spray processes but a certain amount may be suspended, after drying of the road surface, into the air and will contribute to the concentration of particulate matter. Though some measurements of salt concentrations are available near roads, the link between road maintenance salting activities and observed concentrations of salt in ambient air is yet to be quantified.

    In this study the NORTRIP road dust emission model, which estimates the emissions of both dust and salt from the road surface, is applied at five sites in four Nordic countries for ten separate winter periods where daily mean ambient air measurements of salt concentrations are available. The model is capable of reproducing many of the salt emission episodes, both in time and intensity, but also fails on other occasions.

    The observed mean concentration of salt in PM10, over all ten datasets, is 4.2 μg/m3 and the modelled mean is 2.8 μg/m3, giving a fractional bias of −0.38. The RMSE of the mean concentrations, over all 10 datasets, is 2.9 μg/m3 with an average R2 of 0.28. The mean concentration of salt is similar to the mean exhaust contribution during the winter periods of 2.6 μg/m3. The contribution of salt to the kerbside winter mean PM10 concentration is estimated to increase by 4.1 ± 3.4 μg/m3 for every kg/m2 of salt applied on the road surface during the winter season. Additional sensitivity studies showed that the accurate logging of salt applications is a prerequisite for predicting salt emissions, as well as good quality data on precipitation. It also highlights the need for more simultaneous measurements of salt loading together with ambient air concentrations to help improve model parameterisations of salt and moisture removal processes.

  • 39.
    Denby, Bruce Rolstad
    et al.
    The Norwegian Institute for Air Research (NILU).
    Sundvor, Ingrid
    The Norwegian Institute for Air Research (NILU).
    Johansson, Christer I.
    Stockholms universitet.
    Pirjola, Liisa H.
    Helsinki Metropolia University of Applied Sciences.
    Ketzel, Matthias
    Aarhus Universitet.
    Norman, Michael A.
    Environment and Health Protection Administration of the City of Stockholm.
    Kupiainen, Kaarle J.
    Nordic Envicon Oy.
    Gustafsson, Mats
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Kauhaniemi, Mari
    Finish Meteorological Institute (FMI).
    Omstedt, Gunnar
    SMHI.
    A coupled road dust and surface moisture model to predict non-exhaust road traffic induced particle emissions (NORTRIP). Part 2: Surface moisture and salt impact modelling2013In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 81, p. 485-503Article in journal (Refereed)
    Abstract [en]

    Non-exhaust traffic induced emissions are a major source of airborne particulate matter in most European countries. This is particularly important in Nordic and Alpine countries where winter time road traction maintenance occurs, e.g. salting and sanding, and where studded tyres are used. Though the total mass generated by wear sources is a key factor in non-exhaust emissions, these emissions are also strongly controlled by surface moisture conditions. In this paper, Part 2, the road surface moisture submodel of a coupled road dust and surface moisture model (NORTRIP) is described.

    We present a description of the road surface moisture part of the model and apply the coupled model to seven sites in Stockholm, Oslo, Helsinki and Copenhagen over 18 separate periods, ranging from 3.5 to 24 months. At two sites surface moisture measurements are available and the moisture sub-model is compared directly to these observations. The model predicts the frequency of wet roads well at both sites, with an average fractional bias of -2.6%. The model is found to correctly predict the hourly surface state, wet or dry, 85% of the time. From the 18 periods modelled using the coupled model an average absolute fractional bias of 15% for PM10 concentrations was found. Similarly the model predicts the 90'th daily mean percentiles of PMio with an average absolute bias of 19% and an average correlation (R-2) of 0.49. When surface moisture is not included in the modelling then this average correlation is reduced to 0.16, demonstrating the importance of the surface moisture conditions. Tests have been carried out to assess the sensitivity of the model to model parameters and input data. The model provides a useful tool for air quality management and for improving our understanding of non-exhaust traffic emissions.

  • 40.
    Denby, Bruce Rolstad
    et al.
    The Norwegian Institute for Air Research (NILU)..
    Sundvor, Ingrid
    The Norwegian Institute for Air Research (NILU)..
    Johansson, Christer
    Stockholms universitet.
    Pirjola, Liisa
    Helsinki Metropolia University of Applied Sciences..
    Ketzel, Matthias
    Aarhus Universitet.
    Norman, Michael
    Environment and Health Protection Administration of the City of Stockholm..
    Kupiainen, Kaarle
    Nordic Envicon Oy..
    Gustafsson, Mats
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Omstedt, Gunnar
    SMHI.
    A coupled road dust and surface moisture model to predict non-exhaust road traffic induced particle emissions (NORTRIP). Part 1: Road dust loading and suspension modelling2013In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 77, p. 283-300Article in journal (Refereed)
    Abstract [en]

    Non-exhaust traffic induced emissions are a major source of particle mass in most European countries. This is particularly important in Nordic and Alpine countries where winter time road traction maintenance occurs, e.g. salting and sanding, and where studded tyres are used. In this paper, Part 1, the road dust sub-model of a coupled road dust and surface moisture model (NORTRIP) is described. The model provides a generalised process based formulation of the non-exhaust emissions, with emphasis on the contribution of road wear, suspension, surface dust loading and the effect of road surface moisture (retention of wear particles and suspended emissions). The model is intended for use as a tool for air quality managers to help study the impact of mitigation measures and policies. We present a description of the road dust sub-model and apply the model to two sites in Stockholm and Copenhagen where seven years of data with surface moisture measurements are available. For the site in Stockholm, where studded tyres are in use, the model predicts the PM10 concentrations very well with correlations (R-2) in the range of R-2 = 0.76-0.91 for daily mean PM10. The model also reproduces well the impact of a reduction in studded tyres at this site. For the site in Copenhagen the correlation is lower, in the range 0.44-0.51. The addition of salt is described in the model and at both sites this leads to improved correlations due to additional salt emissions. For future use of the model a number of model parameters, e.g. wear factors and suspension rates, still need to be refined. The effect of sanding on PM10 emissions is also presented but more information will be required before this can be confidently applied for management applications. (C) 2013 Elsevier Ltd. All rights reserved.

  • 41.
    Deng, Qihong
    et al.
    Cent S Univ, Sch Energy Sci & Engn, Changsha, Hunan, Peoples R China.;Cent S Univ, XiangYa Sch Publ Hlth, Changsha, Hunan, Peoples R China..
    Lu, Chan
    Cent S Univ, Sch Energy Sci & Engn, Changsha, Hunan, Peoples R China..
    Li, Yuguo
    Univ Hong Kong, Dept Mech Engn, Hong Kong, Hong Kong, Peoples R China..
    Chen, Lv
    Cent S Univ, XiangYa Sch Publ Hlth, Changsha, Hunan, Peoples R China..
    He, Yanrong
    Cent S Univ, Sch Energy Sci & Engn, Changsha, Hunan, Peoples R China..
    Sundell, Jan
    Cent S Univ, Sch Energy Sci & Engn, Changsha, Hunan, Peoples R China.;Tsinghua Univ, Sch Architecture, Beijing, Peoples R China..
    Norbäck, Dan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Occupational and Environmental Medicine. Cent S Univ, Sch Energy Sci & Engn, Changsha, Hunan, Peoples R China.
    Association between prenatal exposure to industrial air pollution and onset of early childhood ear infection in China2017In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 157, p. 18-26Article in journal (Refereed)
    Abstract [en]

    Background: Otitis media (OM) is a common infection in early childhood with repeated attacks that lead to long-term complications and sequelae, but its etiology still remains unclear. Objective: To examine the association between early life exposure to air pollution and childhood OM, with the purpose of identifying critical windows of exposure and key components of air pollution in the development of OM. Methods: We conducted a prospective cohort study of 1617 children aged 3-4 years in Changsha, China (2011-2012). The prevalence of OM was assessed by a questionnaire administered by the parents. Individual exposures to nitrogen dioxide (NO2), sulfur dioxide (SO2) and particulate matter with an aerodynamic diameter <= 10 gm (PM10) during prenatal, postnatal, and current windows were estimated using the measured concentrations at monitoring stations. We used logistic regression model to examine the OM risk in terms of odds ratio (OR) and 95% confidence interval (CI) for exposure to different air pollutants during different timing windows, adjusting for covariates, multi-pollutants, and multi windows. Results: Life-time prevalence of doctor-diagnosed OM in preschool children in Changsha was 7.3%. Childhood OM was associated only with prenatal exposure to the industrial air pollution with adjusted OR (95% CI) = 1.44 (1.09-1.88) for a 27 g/m(3) increase in SO2, particularly during the first trimester of pregnancy. We further found that prenatal SO2 exposure was not associated with the repeated attacks but was associated with the onset of OM, adjusted OR (95% CI) = 1.47 (1.10-1.96). The association between prenatal SO2 exposure and early childhood OM was robust after adjusting for other pollutants and windows. Sensitivity analysis indicated that the association was stronger in females, children with parental atopy, and children living in houses with cockroaches, new redecoration, and condensation on window pane during winter. Conclusion: We provide new evidence that prenatal exposure to industrial air pollution is associated with early childhood OM in China and may contribute to the onset of childhood OM. Our findings are helpful in developing more effective preventative strategies for childhood OM. (C) 2017 Elsevier Ltd. All rights reserved.

  • 42.
    Devasthale, Abhay
    et al.
    SMHI, Research Department, Atmospheric remote sensing.
    Thomas, Manu Anna
    SMHI, Research Department, Air quality.
    An investigation of statistical link between inversion strength and carbon monoxide over Scandinavia in winter using AIRS data2012In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 56, p. 109-114Article in journal (Refereed)
    Abstract [en]

    Temperature inversions influence the local air quality at smaller scales and the pollution transport at larger spatio-temporal scales and are one of the most commonly observed meteorological phenomena over Scandinavia (54 degrees N-70 degrees N, 0-30 degrees E) during winter. Here, apart from presenting key statistics on temperature inversions, a large-scale co-variation of inversion strength and carbon monoxide (CO), an ideal pollution tracer, is further quantified at six vertical levels in the free troposphere during three distinct meteorological regimes that are identified based on inversion strength. Collocated temperature and CO profiles from Atmospheric Infrared Sounder (AIRS) are used for this purpose. Higher values of CO (up to 15%) are observed over Scandinavia during weakly stable regimes at all vertical levels studied, whereas lower CO values (up to 10%) are observed when inversions become stronger and elevated. The observed systematic co-variation between CO and inversion strength in three meteorological regimes is most likely explained by the efficacy of long-range transport to influence tropospheric composition over Scandinavia. We argue that this large-scale co-variation of temperature inversions and CO would be a robust metric to test coupling of large-scale meteorology and chemistry in transport models. (C) 2012 Elsevier Ltd. All rights reserved.

  • 43.
    Dingwell, Adam
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Rutgersson, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Claremar, Björn
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Arellano, S.
    Chalmers, Dept Earth & Space Sci, S-41296 Gothenburg, Sweden.
    Mapendano, Y.
    Observ Volcanol Goma, Goma, DEM REP CONGO.
    Galle, B.
    Chalmers, Dept Earth & Space Sci, S-41296 Gothenburg, Sweden.
    Seasonal and diurnal patterns in the dispersionof SO2 from Mt. Nyiragongo2016In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 132, p. 19-29Article in journal (Refereed)
    Abstract [en]

    Mt. Nyiragongo is an active volcano located in the Democratic Republic of Congo, close to the border of Rwanda and about 15 km north of the city of Goma (similar to 1,000,000 inhabitants). Gases emitted from Nyiragongo might pose a persistent hazard to local inhabitants and the environment. While both ground- and satellite-based observations of the emissions exist, prior to this study, no detailed analysis of the dispersion of the emissions have been made. We have conducted a dispersion study, using a modelling system to determine the geographical distribution of SO2. A combination of a meteorological model (WRF), a Lagrangian particle dispersion model (FLEXPART-WRF) and flux data based on DOAS measurements from the NOVAC-network is used. Since observations can only be made during the day, we use random sampling of fluxes and ensemble modelling to estimate night-time emissions. Seasonal variations in the dispersion follows the migration of the Inter Tropical Convergence Zone. In June-August, the area with the highest surface concentrations is located to the northwest, and in December-February, to the southwest of the source. Diurnal variations in surface concentrations were determined by the development of the planetary boundary layer and the lake-/land breeze cycle around lake Kivu. Both processes contribute to low surface concentrations during the day and high concentrations during the night. However, the strong northerly trade winds in November-March weakened the lake breeze, contributing to higher daytime surface concentrations along the northern shore of Lake Kivu, including the city of Goma. For further analysis and measurements, it is important to include both seasonal and diurnal cycles in order to safely cover periods of high and potentially hazardous concentrations.

  • 44.
    Edvardsson, Karin
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Highway and Railway Engineering.
    Magnusson, Rolf
    Dalarna Högskolan.
    Monitoring of dust emission on gravel roads: Development of a mobile methodology and examination of horizontal diffusion2009In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 43, no 4, p. 889-896Article in journal (Refereed)
    Abstract [en]

    Traffic-generated fugitive dust on gravel roads impairs visibility and deposits on the adjacent environment. Particulate matter smaller than 10 mu m in diameter (PM10) is also associated with human health problems. Dust emission strength depends on the composition of granular material, road moisture, relative humidity, local Climate (precipitation, wind velocity, etc.), and vehicle characteristics.

    The objectives of this study Were to develop a reliable and rapid mobile methodology to measure dust concentrations on gravel roads, evaluate the precision and repeatability of the methodology and correspondence with the currently used Visual assessment technique. Downwind horizontal diffusion was studied to evaluate the risk of exceeding the maximum allowed particulate matter concentration in ambient air near gravel roads according to European Council Directive [European Council Directive 1999/30/EC of 22 April 1999 relating to limit values for sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter and lead in ambient air. Official Journal of the European Communities. L163/41.].

    A TSI DustTrak Aerosol Monitor was mounted on an estate car travelling along test sections treated with various dust suppressants. Measured PM10 concentrations were compared to Visual assessments performed at the same time. Airborne particles were collected in filters Mounted behind the vehicle to compare the whole dust fraction with the PM10 concentration. For measuring the horizontal diffusion, DustTraks were placed at Various distances downwind of a dusty road section.

    The mobile methodology was vehicle and speed dependent but not driver dependent with pre-specified driving behaviours. A high linear correlation between PM10 of different vehicles makes relative measurements of dust concentrations possible. The methodology gives continuous data series, mobility, and easy handling and provides fast, reliable and inexpensive measurements for estimating road conditions to make road maintenance more efficient.

    Good correlations between measured PM10-values, visually assessed dust generation and dust collected in filters were obtained. PM10 seems to be correlated to the whole dust fraction that impairs visibility on gravel roads.

    A decay in PM10 concentration as a function of distance from the road was observed. Measured particles principally did not travel further than 45 m from the road. The risk of exceeding the PM10 concentration stated in the EC-directive seems small.

  • 45. Emberson, L. D.
    et al.
    Bueker, P.
    Ashmore, M. R.
    Mills, G.
    Jackson, L. S.
    Agrawal, M.
    Atikuzzaman, M. D.
    Cinderby, S.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Jamir, C.
    Kobayashi, K.
    Oanh, N. T. K.
    Quadir, Q. F.
    Wahid, A.
    A comparison of North American and Asian exposure-response data for ozone effects on crop yields2009In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 43, no 12, p. 1945-1953Article, review/survey (Refereed)
    Abstract [en]

    Modelling-based studies to assess the extent and magnitude of ozone (O-3) risk to agriculture in Asia suggest that yield losses of 5-20% for important crops may be common in areas experiencing elevated O-3 concentrations. These assessments have relied on European and North American dose-response relationships and hence assumed an equivalent Asian crop response to O-3 for local cultivars, pollutant conditions and climate. To test this assumption we collated comparable dose-response data derived from fumigation, filtration and EDU experiments conducted in Asia on wheat. rice and leguminous crop species. These data are pooled and compared with equivalent North American dose-response relationships. The Asian data show that at ambient O-3 concentrations found at the study sites (which vary between similar to 35-75 ppb 4-8 h growing season mean), yield losses for wheat, rice and legumes range between 5-48, 3-47 and 10-65%, respectively. The results indicate that Asian grown wheat and rice cultivars are more sensitive to O-3 than the North American dose-response relationships would suggest. For legumes the scatter in the data makes it difficult to reach any equivalent conclusion in relative sensitivities. As such, existing modelling-based risk assessments may have substantially underestimated the scale of the problem in Asia through use of North American derived dose-response relationships. (c) 2009 Elsevier Ltd. All rights reserved.

  • 46.
    Eneroth, Kristina
    et al.
    Stockholm University, Faculty of Science, Department of Meteorology .
    Holmen, Kim
    Berg, Torunn
    Schmidbauer, Norbert
    Solberg, Sverre
    Springtime depletion of tropospheric ozone, gaseous elemental mercury and non-methane hydrocarbons in the European Arctic, and its relation to atmospheric transport2007In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 41, no 38, p. 8511-8526Article in journal (Refereed)
    Abstract [en]

    Using a trajectory climatology for the period 1992-2001 we have examined how seasonal changes in transport cause changes in the concentrations of tropospheric ozone (O-3), gaseous elemental mercury (GEM) and non-methane hydrocarbons (NMHCs) observed at the Mt. Zeppelin station, Ny-angstrom lesund (78.9 degrees N, 11.9 degrees E). During April-June O-3 depletion events were frequently observed in connection with air transport across the Arctic Basin. The O-3 loss was most pronounced in air masses advected close to the surface. This result supports the idea that the O-3 depletion reactions take place in the lowermost part of the atmosphere in the central Arctic Basin. A strong positive correlation between springtime O-3 depletion events and the oxidation of GEM to divalent mercury was found. During air mass advection from Siberia, the Barents Sea and the Norwegian Sea the strongest correlation was observed during April-May, whereas air masses originating from the Canadian Arctic and the central Arctic areas showed the highest O-3-GEM correlation in May-June. We suggest that this 1-month lag could either be due to the position of the marginal ice zone or temperature differences between the northwestern and northeastern air masses. In connection with springtime O-3 depletion events low concentrations of some NMHCs, especially ethane and ethyne, were observed, indicating that both bromine (ethyne oxidant) and chlorine radicals (ethane oxidant) are present in the Arctic atmosphere during spring. In winter, negative correlations between O-3 and NMHCs were found in connection with air transport from Europe and Siberia, which we interpret as O-3 destruction taking place in industrially contaminated plumes.

  • 47.
    Engardt, Magnuz
    et al.
    SMHI, Research Department, Air quality.
    Leong, C P
    Regional modelling of anthropogenic sulphur in Southeast Asia2001In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 35, no 34, p. 5935-5947Article in journal (Refereed)
    Abstract [en]

    A co-operative research project between the Malaysian Meteorological Service (MMS) and the Swedish Meteorological and Hydrological Institute (SMHI) focussing on the usage of an atmospheric transport and chemistry model, has just been initiated. Here, we describe the main features of the dispersion model and discuss a first set of calculations in light of available measurements of sulphuric species in Southeast Asia. According to our results, anthropogenic sulphur concentrations and depositions are particularly high near the large cities of the region, around a metal smelter in the southern Philippines, and in a region extending from northern Vietnam into southeastern China. These areas coincide with the high-emissions regions of Southeast Asia and we tentatively conclude that regional transport of acidifying species is not as far-reaching as in the mid-latitudes. From our calculations, and from supporting measurements we conclude that most of rural Southeast Asia is not yet severely affected by anthropogenic sulphur, but given the rapid rate of economical development in this region the situation may deteriorate quickly. Areas that are particularly at risk include the large cities, northern Vietnam, most of central Thailand, most of peninsular Malaysia, eastern Sumatra and parts of Java, all of which receive total-sulphur depositions in excess of 0.5 g S m(-2) yr(-1). Our model simulates sulphate in precipitation in accordance with measurements, but it has a tendency to overestimate atmospheric SO2. It remains to be investigated whether this is a problem in the model formulation or a result of unrepresentative sampling. An immediate continuation of this study should be performed with higher spatial resolution than the currently used 100 x 100 km(2). Other imperfections in this model study, which should be addressed in future work, include parameterised vertical transport in deep convective clouds, the influence of natural emissions (primarily from volcanoes) on the concentration and deposition of sulphuric species, and the year-to-year variability of the driving meteorological conditions. (C) 2001 Elsevier Science Ltd. All rights reserved.

  • 48.
    Engardt, Magnuz
    et al.
    SMHI, Research Department, Air quality.
    Siniarovina, U
    Khairul, N I
    Leong, C P
    Country to country transport of anthropogenic sulphur in Southeast Asia2005In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 39, no 28, p. 5137-5148Article in journal (Refereed)
    Abstract [en]

    The MATCH model-driven by archived meteorological data from the ECMWF-has been used to study the long-range transport of pollutants in Southeast Asia during the year 2000. We have specifically investigated the atmospheric export and import of anthropogenic sulphur between nine countries in Southeast Asia as well as the import to these countries from the boundaries of our model domain, from southern China, and from international shipping in the surrounding waters. Compared to the conditions at the mid-latitudes (Europe, North America and East Asia), we find less long-range transport in this part of the world. In all countries in the region (except those with very small area, i.e. Singapore and Brunei), did the major part of the domestic emissions (60-70%) fall down on the emitting country itself. The fraction of the countries own emissions contributing to the total, annually accumulated, national deposition varied from 10% for Laos-which is a country with small emissions neighbouring large emitters-to 80-90% in countries not surrounded by significant emitters (i.e. Thailand, Indonesia, Singapore and Brunei). Sensitivity tests were performed to explore the uncertainties in the model simulations and to investigate to what extent the current results could be used for source-receptor relationships in the future, when the magnitude and location of the emissions may be different. We found that the general feature-with relatively little long-range transport of sulphur-will not be altered, while the absolute magnitude of the deposition in areas downwind of large emitters could change considerably if certain model parameters, or the emission patterns are changed. This is particularly true in light of the seasonal variation of the deposition pathways. The atmospheric import of anthropogenic sulphur from specific countries can vary by an order of magnitude between different months. Incidentally, a decrease in import from one country during a certain period is often compensated by a roughly equal increase of the import from another country during the same time. (c) 2005 Elsevier Ltd. All rights reserved.

  • 49. Fauser, P.
    et al.
    Ketzel, M.
    Becker, T.
    Plejdrup, M. S.
    Brandt, J.
    Gidhagen, Lars
    SMHI, Research Department, Air quality.
    Omstedt, Gunnar
    SMHI, Research Department, Air quality.
    Skarman, T.
    Bartonova, A.
    Schwarze, P.
    Karvosenoja, N.
    Paunu, V. -V
    Kukkonen, J.
    Karppinen, A.
    Human exposure to carcinogens in ambient air in Denmark, Finland and Sweden2017In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 167, p. 283-297Article in journal (Refereed)
  • 50.
    Fick, Jerker
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Pommer, Linda
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Andersson, Barbro
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Nilsson, Calle
    Unit for Biomass Technology and Chemistry, Swedish University of Agricultural Sciences, Umeå.
    A study of the gas-phase ozonolysis of terpenes: the impact of radicals formed during the reaction2002In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 36, no 20, p. 3299-3308Article in journal (Refereed)
    Abstract [en]

    The gas-phase ozonolysis of α-pinene, Δ3-carene and limonene was investigated at ppb levels and the impact of the ozone, relative air humidity (RH), and time was studied using experimental design. The amounts of terpene reacted varied in the different settings and were as high as 8.1% for α-pinene, 10.9% forΔ3-carene and 23.4% for limonene. The designs were able to describe almost all the variation in the experimental data and were also successful in predicting omitted values. The results described the effects of time and ozone and also showed that RH did not have a statistically significant effect on the ozonolysis. The results also showed that all three terpenes were affected by an additional oxidation of OH radicals and/or other reactive species. The results from the designs states that this additional oxidation was responsible for 40% of the total amount of α-pinene reacted, 33% of the total amount of Δ3-carene reacted and 41% of the total amount of limonene reacted at the settings 20 ppb terpene, 75 ppb ozone, 20% RH and a reaction time of 213 s. Additional experiments with 2-butanol as OH radical scavenger showed that the reaction with OH radicals was responsible for 37% of the total α-pinene reacted and 39% of the total Δ3-carene reacted at the same settings. The scavenger experiments also showed that there were no significant amounts of OH radicals formed during the ozonolysis of limonene. The results from the designs were also compared to a mathematical model in order to evaluate further the data.

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