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  • 301. Siniarovina, U
    et al.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    High-resolution model simulations of anthropogenic sulphate and sulphur dioxide in Southeast Asia2005In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 39, no 11, p. 2021-2034Article in journal (Refereed)
    Abstract [en]

    The Multiple-scale Atmospheric Transport and CHemical modelling system (MATCH)-driven by meteorological data from the ECMWF has been applied to a model domain covering Southeast Asia to complete a simulation extending over the full year of 2000. The current paper presents an evaluation of the model performance using archived chemical and meteorological data collected in the region during the year 2000. The calculated sulphate concentrations (on atmospheric aerosols and in precipitation) compare reasonably with observations while the atmospheric SO(2) mixing ratios show worse correspondence. This latter mismatch is attributed to local variations in the measured SO(2) concentrations that are not resolved in the regional model and possible miss-location of the emissions in our model. It can also be pointed out that different laboratories measuring SO(2) at the same site occasionally report SO(2) concentrations that differs by an order of magnitude or more. The seasonal variations of the modelled species are less than initially expected but generally in accordance with the measurements available. Most of the Malaysian cities have comparatively low concentrations of sulphate in precipitation. This is supported both by the model results and by independent measurements. From the model simulations and the measurements, it is concluded that the sulphur deposition is still relatively low (i.e. < 0.5 g sulphur m(-2) year(-1)) in most of rural Malaysia. This is also the case in Myanmar, Laos, central Vietnam, Kampuchea and southern Thailand. The situation in the vicinity of the large cities in the region is, however, much worse and the deposition is similar, or larger, than estimated critical loads. (c) 2005 Elsevier Ltd. All rights reserved.

  • 302. SJODIN, A
    et al.
    LOMAN, G
    Omstedt, Gunnar
    SMHI, Research Department, Air quality.
    LONG-TERM CONTINUOUS MEASUREMENTS OF AIR POLLUTANT CONCENTRATIONS, METEOROLOGY AND TRAFFIC ON A RURAL MOTORWAY AND A MODEL VALIDATION1994In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 147, p. 365-375Article in journal (Refereed)
    Abstract [en]

    Air concentrations of carbon monoxide (CO), nitrogen oxide (NO) and nitrogen dioxide (NO2) were continuously monitored at a rural motorway site in Sweden for the period February-December 1990. In addition, local meteorology and traffic parameters were measured in order to validate a dispersion model. Even close to the motorway, the concentrations of CO and NO2 were well below Swedish air quality guidelines. For long-term averages the regional background contributed significantly to the downwind levels. The atmospheric reaction between primary emitted NO and background ozone (O3) tends to be a major source of downwind NO2, also fairly close to the road (10 m from the road shoulder), where the average NO2/NO(x) ratio was approximately 0.4. The validated model employs a percentile analysis on the basis of the HIWAY-2 and CALINE4 models and a separate emission model. The agreement between measured and modelled data, as refered to the 98th percentile, was good for NO2 but moderate for CO. This is probably partly caused by uncertainties in emission factors for CO for heavy vehicles. Since a good agreement was observed between measured and calculated NO(x) concentrations, problems in adequately modelling NO2 are probably associated with uncertainties as to NO2/NO(x) ratios in the exhaust, or the modelling of the O3 reaction.

  • 303. Soares, Joana
    et al.
    Sofiev, Mikhail
    Geels, Camilla
    Christensen, Jens H.
    Andersson, Camilla
    SMHI, Research Department, Air quality.
    Tsyro, Svetlana
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Impact of climate change on the production and transport of sea salt aerosol on European seas2016In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 16, no 20, p. 13081-13104Article in journal (Refereed)
  • 304. Sofiev, M.
    et al.
    Berger, U.
    Prank, M.
    Vira, J.
    Arteta, J.
    Belmonte, J.
    Bergmann, K. -C
    Cheroux, F.
    Elbern, H.
    Friese, E.
    Galan, C.
    Gehrig, R.
    Khvorostyanov, D.
    Kranenburg, R.
    Kumar, U.
    Marecal, V.
    Meleux, F.
    Menut, L.
    Pessi, A. -M
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Ritenberga, O.
    Rodinkova, V.
    Saarto, A.
    Segers, A.
    Severova, E.
    Sauliene, I.
    Siljamo, P.
    Steensen, B. M.
    Teinemaa, E.
    Thibaudon, M.
    Peuch, V. -H
    MACC regional multi-model ensemble simulations of birch pollen dispersion in Europe2015In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 15, no 14, p. 8115-8130Article in journal (Refereed)
    Abstract [en]

    This paper presents the first ensemble modelling experiment in relation to birch pollen in Europe. The seven-model European ensemble of MACC-ENS, tested in trial simulations over the flowering season of 2010, was run through the flowering season of 2013. The simulations have been compared with observations in 11 countries, all members of the European Aeroallergen Network, for both individual models and the ensemble mean and median. It is shown that the models successfully reproduced the timing of the very late season of 2013, generally within a couple of days from the observed start of the season. The end of the season was generally predicted later than observed, by 5 days or more, which is a known feature of the source term used in the study. Absolute pollen concentrations during the season were somewhat underestimated in the southern part of the birch habitat. In the northern part of Europe, a record-low pollen season was strongly overestimated by all models. The median of the multi-model ensemble demonstrated robust performance, successfully eliminating the impact of outliers, which was particularly useful since for most models this was the first experience of pollen forecasting.

  • 305. Sofiev, Mikhail
    et al.
    Ritenberga, Olga
    Albertini, Roberto
    Arteta, Joaquim
    Belmonte, Jordina
    Bernstein, Carmi Geller
    Bonini, Maira
    Celenk, Sevcan
    Damialis, Athanasios
    Douros, John
    Elbern, Hendrik
    Friese, Elmar
    Galan, Carmen
    Oliver, Gilles
    Hrga, Ivana
    Kouznetsov, Rostislav
    Krajsek, Kai
    Magyar, Donat
    Parmentier, Jonathan
    Plu, Matthieu
    Prank, Marje
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Steensen, Birthe Marie
    Thibaudon, Michel
    Segers, Arjo
    Stepanovich, Barbara
    Valdebenito, Alvaro M.
    Vira, Julius
    Vokou, Despoina
    Multi-model ensemble simulations of olive pollen distribution in Europe in 2014: current status and outlook2017In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 17, no 20, p. 12341-12360Article in journal (Refereed)
  • 306. Solberg, S
    et al.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Laurila, T
    Lindskog, A
    Changes in Nordic surface ozone episodes due to European emission reductions in the 1990s2005In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 39, no 1, p. 179-192Article in journal (Refereed)
    Abstract [en]

    Based on analyses of model calculations with a regional scale CTM for two different years and measurement data from background locations in northern Europe, we have found several indications that peak ozone value, in the Nordic countries have been reduced during the 1990s as a result of reduced emissions of precursors in Europe. Official European emission data for 1999 gave a better model performance than the emission data for 1990 when modelling 1999 and 2000. A bootstrap resampling technique indicated that the improvement in performance was significant. The model predicted a reduction in peak ozone values of the order of 30 mug m(-3) due to European emission reductions during the 1990s in the Nordic countries. It is thus likely that the number of exceedances of hourly threshold values has been reduced, although the small number of episodes does not allow strict statements. The number and magnitude of the ozone episodes as well as the model performance was clearly higher for southern Sweden and Norway compared to Finland, presumably reflecting differences in meteorological transport and emission source regions. (C) 2004 Elsevier Ltd. All rights reserved.

  • 307. Solberg, S
    et al.
    Derwent, R G
    Hov, O
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Lindskog, A
    European abatement of surface ozone in a global perspective2005In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 34, no 1, p. 47-53Article in journal (Refereed)
    Abstract [en]

    EU's programme Clean Air for Europe (CAFE) is presently revising the policy on air quality which will lead to the adoption of a thematic strategy on air pollution under the Sixth Environmental Action Programme by mid-2005. For the abatement of surface ozone it is becoming evident that processes outside European control will be crucial for meeting long-term aims and air quality guidelines in Europe in the future. Measurements and modelling results indicate that there is a strong link between climate change and surface ozone. A warmer and dryer European climate is very likely to lead to increased ozone concentrations. Furthermore, increased anthropogenic emissions in developing economies in Asia are likely to raise the hemispheric background level of ozone. A significant increase in the background concentration of ozone has been observed at several sites in Northern Europe although the underlying causes are not settled. The photochemical formation of tropospheric ozone from increased concentrations of methane and CO may also lead to a higher ozone level on a global scale. Gradually, these effects may outweigh the effect of the reduced European ozone precursor emissions. This calls for a global or hemispheric perspective in the revision of the European air quality policy for ozone.

  • 308. Stockfelt, Leo
    et al.
    Andersson, Eva M.
    Molnar, Peter
    Gidhagen, Lars
    SMHI, Research Department, Air quality.
    Segersson, David
    SMHI, Research Department, Air quality.
    Rosengren, Annika
    Barregard, Lars
    Sallsten, Gerd
    Long-term effects of total and source-specific particulate air pollution on incident cardiovascular disease in Gothenburg, Sweden2017In: Environmental Research, ISSN 0013-9351, E-ISSN 1096-0953, Vol. 158, p. 61-71Article in journal (Refereed)
  • 309.
    Taesler, Roger
    et al.
    SMHI, Research Department.
    Andersson, C.
    SMHI.
    Wallentin, C.
    SMHI.
    Krieg, Roland
    SMHI, Research Department, Air quality.
    Klimatkorrigering för energiförbrukningen i ett eluppvärmt villaområde1987Report (Other academic)
  • 310. Takano, Y.
    et al.
    Liou, K. N.
    Kahnert, Michael
    SMHI, Research Department, Air quality.
    Yang, P.
    The single-scattering properties of black carbon aggregates determined from the geometric-optics surface-wave approach and the T-matrix method2013In: Journal of Quantitative Spectroscopy and Radiative Transfer, ISSN 0022-4073, E-ISSN 1879-1352, Vol. 125, p. 51-56Article in journal (Refereed)
    Abstract [en]

    The single-scattering properties of eight black carbon (BC, soot) fractal aggregates, composed of primary spheres from 7 to 600, computed by the geometric-optics surface-wave (GOS) approach coupled with the Rayleigh-Gans-Debye (RGD) adjustment for size parameters smaller than approximately 2, are compared with those determined from the superposition T-matrix method. We show that under the condition of random orientation, the results from GOS/RGD are in general agreement with those from T-matrix in terms of the extinction and absorption cross-sections, the single-scattering co-albedo, and the asymmetry factor. When compared with the specific absorption (m(2)/g) measured in the laboratory, we illustrate that using the observed radii of primary spheres ranging from 3.3 to 25 nm, the theoretical values determined from GOS/RGD for primary sphere numbers of 100-600 are within the range of measured values. The GOS approach can be effectively applied to aggregates composed of a large number of primary spheres (e.g., > 6000) and large size parameters (>> 2) in terms of computational efforts. (C) 2013 Elsevier Ltd. All rights reserved.

  • 311. Teixeira, J. C.
    et al.
    Fallmann, J.
    Carvalho, Ana
    SMHI, Research Department, Air quality.
    Rocha, A.
    Surface to boundary layer coupling in the urban area of Lisbon comparing different urban canopy models in WRF2019In: Urban Climate, ISSN 2212-0955, E-ISSN 2212-0955, Vol. 28, article id UNSP 100454Article in journal (Refereed)
  • 312. Theobald, Mark R.
    et al.
    Vivanco, Marta G.
    Aas, Wenche
    Andersson, Camilla
    SMHI, Research Department, Air quality.
    Ciarelli, Giancarlo
    Couvidat, Florian
    Cuvelier, Kees
    Manders, Astrid
    Mircea, Mihaela
    Pay, Maria-Teresa
    Tsyro, Svetlana
    Adani, Mario
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Bessagnet, Bertrand
    Briganti, Gino
    Cappelletti, Andrea
    D'Isidoro, Massimo
    Fagerli, Hilde
    Mar, Kathleen
    Otero, Noelia
    Raffort, Valentin
    Roustan, Yelva
    Schaap, Martijn
    Wind, Peter
    Colette, Augustin
    An evaluation of European nitrogen and sulfur wet deposition and their trends estimated by six chemistry transport models for the period 1990-20102019In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 19, no 1, p. 379-405Article in journal (Refereed)
  • 313.
    Thomas, Manu Anna
    et al.
    SMHI, Research Department, Air quality.
    Devasthale, Abhay
    SMHI, Research Department, Atmospheric remote sensing.
    Sensitivity of free tropospheric carbon monoxide to atmospheric weather states and their persistency: an observational assessment over the Nordic countries2014In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 14, no 21, p. 11545-11555Article in journal (Refereed)
    Abstract [en]

    Among various factors that influence the long-range transport of pollutants in the free troposphere (FT), the prevailing atmospheric weather states probably play the most important role in governing characteristics and efficacy of such transport. The weather states, such as a particular wind pattern, cyclonic or anticyclonic conditions, and their degree of persistency determine the spatio-temporal distribution and the final fate of the pollutants. This is especially true in the case of Nordic countries, where baroclinic disturbances and associated weather fronts primarily regulate local meteorology, in contrast to the lower latitudes where a convective paradigm plays a similarly important role. Furthermore, the long-range transport of pollutants in the FT has significant contribution to the total column burden over the Nordic countries. However, there is insufficient knowledge on the large-scale co-variability of pollutants in the FT and atmospheric weather states based solely on observational data over this region. The present study attempts to quantify and understand this statistical co-variability while providing relevant meteorological background. To that end, we select eight weather states that predominantly occur over the Nordic countries and three periods of their persistency (3 days, 5 days, and 7 days), thus providing in total 24 cases to investigate sensitivity of free tropospheric carbon monoxide, an ideal tracer for studying pollutant transport, to these selected weather states. The eight states include four dominant wind directions (namely, NW, NE, SE and SW), cyclonic and anticyclonic conditions, and the enhanced positive and negative phases of the North Atlantic Oscillation (NAO). For our sensitivity analysis, we use recently released Version 6 retrievals of CO at 500 hPa from the Atmospheric Infrared Sounder (AIRS) onboard Aqua satellite covering the 11-year period from September 2002 through August 2013 and winds from the ECMWF's ERA-Interim project to classify weather states for the same 11-year period. We show that, among the various weather states studied here, southeasterly winds lead to highest observed CO anomalies (up to +8%) over the Nordic countries while transporting pollution from the central and eastern parts of Europe. The second (up to +4%) and third highest (up to +2.5%) CO anomalies are observed when winds are northwesterly (facilitating inter-continental transport from polluted North American regions) and during the enhanced positive phase of the NAO respectively. Higher than normal CO anomalies are observed during anticyclonic conditions (up to +1%) compared to cyclonic conditions. The cleanest conditions are observed when winds are northeasterly and during the enhanced negative phases of the NAO, when relatively clean Arctic air masses are transported over the Nordic regions in the both cases. In the case of nearly all weather states, the CO anomalies consistently continue to increase or decrease as the degree of persistency of a weather state is increased. The results of this sensitivity study further provide an observational basis for the process-oriented evaluation of chemistry transport models, especially with regard to the representation of large-scale coupling of chemistry and local weather states and its role in the long-range transport of pollutants in such models.

  • 314.
    Thomas, Manu Anna
    et al.
    SMHI, Research Department, Air quality.
    Devasthale, Abhay
    SMHI, Research Department, Atmospheric remote sensing.
    Kahnert, Michael
    SMHI, Research Department, Air quality.
    Exploiting the favourable alignment of CALIPSO's descending orbital tracks over Sweden to study aerosol characteristics2013In: Tellus. Series B, Chemical and physical meteorology, ISSN 0280-6509, E-ISSN 1600-0889, Vol. 65, article id 21155Article in journal (Refereed)
    Abstract [en]

    One of the key knowledge gaps when estimating aerosol forcing and their role in air quality is our limited understanding of their vertical distribution. As an active lidar in space, the CALIOP-CALIPSO is helping to close this gap. The descending orbital track of CALIPSO follows elongated semi-major axis of Sweden, slicing its atmosphere every 2-3 d, thus providing a unique opportunity to characterise aerosols and their verticality in all seasons irrespective of solar conditions. This favourable orbital configuration of CALIPSO over Sweden is exploited in the present study. Using five years of night-time aerosol observations (2006-2011), we investigated the vertical distribution of aerosols. The role of temperature inversions and winds in governing this distribution is additionally investigated using collocated AIRS-Aqua and ERA-Interim Reanalysis data. It is found that the majority of aerosols (up to 70%) are located within 1 km above the surface in the lowermost troposphere, irrespective of the season. In summer, convection and stronger mixing lift aerosols to slightly higher levels, but their noticeable presence in the upper free troposphere is observed in the winter half of the year, when the boundary layer is decoupled due to strong temperature inversions separating local sources from the transport component. When southerly winds prevail, two or more aerosol layers are most frequent over southern Sweden and the polluted air masses have higher AOD values. The depolarisation ratio and integrated attenuated backscatter of these aerosol layers are also higher. About 30-50% of all aerosol layers are located below the level where temperature inversions peak. On the other hand, relatively cleaner conditions are observed when the winds have a northerly component.

  • 315.
    Thomas, Manu Anna
    et al.
    SMHI, Research Department, Air quality.
    Kahnert, Michael
    SMHI, Research Department, Air quality.
    Andersson, Camilla
    SMHI, Research Department, Air quality.
    Kokkola, H.
    Hansson, Ulf
    SMHI, Research Department, Climate research - Rossby Centre.
    Jones, Colin
    SMHI, Research Department, Climate research - Rossby Centre.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Devasthale, Abhay
    SMHI, Research Department, Atmospheric remote sensing.
    Integration of prognostic aerosol-cloud interactions in a chemistry transport model coupled offline to a regional climate model2015In: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 8, no 6, p. 1885-1898Article in journal (Refereed)
    Abstract [en]

    To reduce uncertainties and hence to obtain a better estimate of aerosol (direct and indirect) radiative forcing, next generation climate models aim for a tighter coupling between chemistry transport models and regional climate models and a better representation of aerosol-cloud interactions. In this study, this coupling is done by first forcing the Rossby Center regional climate model (RCA4) with ERA-Interim lateral boundaries and sea surface temperature (SST) using the standard cloud droplet number concentration (CDNC) formulation (hereafter, referred to as the 'stand-alone RCA4 version' or 'CTRL' simulation). In the stand-alone RCA4 version, CDNCs are constants distinguishing only between land and ocean surface. The meteorology from this simulation is then used to drive the chemistry transport model, Multiple-scale Atmospheric Transport and Chemistry (MATCH), which is coupled online with the aerosol dynamics model, Sectional Aerosol module for Large Scale Applications (SALSA). CDNC fields obtained from MATCH-SALSA are then fed back into a new RCA4 simulation. In this new simulation (referred to as 'MOD' simulation), all parameters remain the same as in the first run except for the CDNCs provided by MATCH-SALSA. Simulations are carried out with this model setup for the period 2005-2012 over Europe, and the differences in cloud microphysical properties and radiative fluxes as a result of local CDNC changes and possible model responses are analysed. Our study shows substantial improvements in cloud microphysical properties with the input of the MATCH-SALSA derived 3-D CDNCs compared to the stand-alone RCA4 version. This model setup improves the spatial, seasonal and vertical distribution of CDNCs with a higher concentration observed over central Europe during boreal summer (JJA) and over eastern Europe and Russia during winter (DJF). Realistic cloud droplet radii (CD radii) values have been simulated with the maxima reaching 13 mu m, whereas in the stand-alone version the values reached only 5 mu m. A substantial improvement in the distribution of the cloud liquid-water paths (CLWP) was observed when compared to the satellite retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS) for the boreal summer months. The median and standard deviation values from the 'MOD' simulation are closer to observations than those obtained using the stand-alone RCA4 version. These changes resulted in a significant decrease in the total annual mean net fluxes at the top of the atmosphere (TOA) by -5 W m(-2) over the domain selected in the study. The TOA net fluxes from the 'MOD' simulation show a better agreement with the retrievals from the Clouds and the Earth's Radiant Energy System (CERES) instrument. The aerosol indirect effects are estimated in the 'MOD' simulation in comparison to the pre-industrial aerosol emissions (1900). Our simulations estimated the domain averaged annual mean total radiative forcing of -0.64 W m(-2) with a larger contribution from the first indirect aerosol effect (-0.57 W m(-2)) than from the second indirect aerosol effect (-0.14 W m(-2)).

  • 316.
    Thomas, Manu Anna
    et al.
    SMHI, Research Department, Air quality.
    Suntharalingam, P.
    Pozzoli, L.
    Devasthale, Abhay
    SMHI, Research Department, Atmospheric remote sensing.
    Kloster, S.
    Rast, S.
    Feichter, J.
    Lenton, T. M.
    Rate of non-linearity in DMS aerosol-cloud-climate interactions2011In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 11, no 21, p. 11175-11183Article in journal (Refereed)
    Abstract [en]

    The degree of non-linearity in DMS-cloud-climate interactions is assessed using the ECHAM5-HAMMOZ model by taking into account end-to-end aerosol chemistry-cloud microphysics link. The evaluation is made over the Southern oceans in austral summer, a region of minimal anthropogenic influence. In this study, we compare the DMS-derived changes in the aerosol and cloud microphysical properties between a baseline simulation with the ocean DMS emissions from a prescribed climatology, and a scenario where the DMS emissions are doubled. Our results show that doubling the DMS emissions in the current climate results in a non-linear response in atmospheric DMS burden and subsequently, in SO2 and H2SO4 burdens due to inadequate OH oxidation. The aerosol optical depth increases by only similar to 20% in the 30 degrees S-75 degrees S belt in the SH summer months. This increases the vertically integrated cloud droplet number concentrations (CDNC) by 25 %. Since the vertically integrated liquid water vapor is constant in our model simulations, an increase in CDNC leads to a reduction in cloud droplet radius of 3.4 % over the Southern oceans in summer. The equivalent increase in cloud liquid water path is 10.7 %. The above changes in cloud microphysical properties result in a change in global annual mean radiative forcing at the TOA of -1.4 W m(-2). The results suggest that the DMS-cloud microphysics link is highly non-linear. This has implications for future studies investigating the DMS-cloud climate feedbacks in a warming world and for studies evaluating geoengineering options to counteract warming by modulating low level marine clouds.

  • 317.
    Thomas, Manu Anna
    et al.
    SMHI, Research Department, Air quality.
    Suntharalingam, P.
    Pozzoli, L.
    Rast, S.
    Devasthale, Abhay
    SMHI, Research Department, Atmospheric remote sensing.
    Kloster, S.
    Feichter, J.
    Lenton, T. M.
    Quantification of DMS aerosol-cloud-climate interactions using the ECHAM5-HAMMOZ model in a current climate scenario2010In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 10, no 15, p. 7425-7438Article in journal (Refereed)
    Abstract [en]

    The contribution of ocean dimethyl sulfide (DMS) emissions to changes in cloud microphysical properties is quantified seasonally and globally for present day climate conditions using an aerosol-chemistry-climate general circulation model, ECHAM5-HAMMOZ, coupled to a cloud microphysics scheme. We evaluate DMS aerosol-cloud-climate linkages over the southern oceans where anthropogenic influence is minimal. The changes in the number of activated particles, cloud droplet number concentration (CDNC), cloud droplet effective radius, cloud cover and the radiative forcing are examined by analyzing two simulations: a baseline simulation with ocean DMS emissions derived from a prescribed climatology and one in which the ocean DMS emissions are switched off. Our simulations show that the model realistically simulates the seasonality in the number of activated particles and CDNC, peaking during Southern Hemisphere (SH) summer coincident with increased phyto-plankton blooms and gradually declining with a minimum in SH winter. In comparison to a simulation with no DMS, the CDNC level over the southern oceans is 128% larger in the baseline simulation averaged over the austral summer months. Our results also show an increased number of smaller sized cloud droplets during this period. We estimate a maximum decrease of up to 15-18% in the droplet radius and a mean increase in cloud cover by around 2.5% over the southern oceans during SH summer in the simulation with ocean DMS compared to when the DMS emissions are switched off. The global annual mean top of the atmosphere DMS aerosol all sky radiative forcing is -2.03 W/m(2), whereas, over the southern oceans during SH summer, the mean DMS aerosol radiative forcing reaches -9.32 W/m(2).

  • 318.
    Thomas, Manu
    et al.
    SMHI, Research Department, Air quality.
    Brannstrom, Niklas
    Persson, Christer
    SMHI, Professional Services.
    Grahn, Hakan
    von Schoenberg, Pontus
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Surface air quality implications of volcanic injection heights2017In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 166, p. 510-518Article in journal (Refereed)
  • 319.
    Thomas, Manu
    et al.
    SMHI, Research Department, Air quality.
    Devasthale, Abhay
    SMHI, Research Department, Atmospheric remote sensing.
    Typical meteorological conditions associated with extreme nitrogen dioxide (NO2) pollution events over Scandinavia2017In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 17, no 19, p. 12071-12080Article in journal (Refereed)
  • 320.
    Thomas, Manu
    et al.
    SMHI, Research Department, Air quality.
    Devasthale, Abhay
    SMHI, Research Department, Atmospheric remote sensing.
    Koenigk, Torben
    SMHI, Research Department, Climate research - Rossby Centre.
    Wyser, Klaus
    SMHI, Research Department, Climate research - Rossby Centre.
    Roberts, Malcolm
    Roberts, Christopher
    Lohmann, Katja
    A statistical and process-oriented evaluation of cloud radiative effects in high-resolution global models2019In: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 12, no 4, p. 1679-1702Article in journal (Refereed)
  • 321.
    Thomas, Manu
    et al.
    SMHI, Research Department, Air quality.
    Devasthale, Abhay
    SMHI, Research Department, Atmospheric remote sensing.
    L'Ecuyer, Tristan
    Wang, Shiyu
    SMHI, Research Department, Climate research - Rossby Centre.
    Koenigk, Torben
    SMHI, Research Department, Climate research - Rossby Centre.
    Wyser, Klaus
    SMHI, Research Department, Climate research - Rossby Centre.
    Snowfall distribution and its response to the Arctic Oscillation: an evaluation of HighResMIP models in the Arctic using CPR/CloudSat observations2019In: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 12, no 8, p. 3759-3772Article in journal (Refereed)
  • 322.
    Thomas, Manu
    et al.
    SMHI, Research Department, Air quality.
    Devasthale, Abhay
    SMHI, Research Department, Atmospheric remote sensing.
    Tjernstrom, Michael
    Ekman, Annica M. L.
    The Relation Between Aerosol Vertical Distribution and Temperature Inversions in the Arctic in Winter and Spring2019In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 46, no 5, p. 2836-2845Article in journal (Refereed)
  • 323. Tilmes, S
    et al.
    Brandt, J
    Flatoy, F
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Flemming, J
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Christensen, J H
    Frohn, L M
    Hov, O
    Jacobsen, I
    Reimer, E
    Stern, R
    Zimmermann, J
    Comparison of five eulerian air pollution forecasting systems for the summer of 1999 using the German ozone monitoring data2002In: Journal of Atmospheric Chemistry, ISSN 0167-7764, E-ISSN 1573-0662, Vol. 42, no 1, p. 91-121Article in journal (Refereed)
    Abstract [en]

    Eulerian state-of-the-art air pollution forecasting systems on the European scale are operated routinely by several countries in Europe. DWD and FUB, both Germany, NERI, Denmark, NILU, Norway, and SMHI, Sweden, operate some of these systems. To apply such modeling systems, e.g. for regulatory purposes according to new EU directives, an evaluation and comparison of the model systems is fundamental in order to assess their reliability. One step in this direction is presented in this study: The model forecasts from all five systems have been compared to measurements of ground level ozone in Germany. The outstanding point in this investigation is the availability of a huge amount of data - from forecasts by the different model systems and from observations. This allows for a thorough interpretation of the findings and assures the significance of the observed features. Data from more than 300 measurement stations for a 5-month period (May-September 1999) of the German monitoring networks have been used in this comparison. Different spatial and temporal statistical parameters were applied in the evaluation. Generally, it was found that the most comprehensive models gave the best results. However, the less comprehensive and computational cheaper models also produced good results. The extensive comparison made it possible to point out weak points in the different models and to describe the individual model behavior for a full summer period in a climatological sense. The comparison also gave valuable information for an assessment of individual measurement stations and complete monitoring networks in terms of the representativeness of the observation data.

  • 324. van der Gon, H. A. C. Denier
    et al.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Fountoukis, C.
    Johansson, C.
    Pandis, S. N.
    Simpson, D.
    Visschedijk, A. J. H.
    Particulate emissions from residential wood combustion in Europe revised estimates and an evaluation2015In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 15, no 11, p. 6503-6519Article in journal (Refereed)
    Abstract [en]

    Currently residential wood combustion (RWC) is increasing in Europe because of rising fossil fuel prices but also due to climate change mitigation policies. However, especially in small-scale applications, RWC may cause high emissions of particulate matter (PM). Recently we have developed a new high-resolution (7 x 7 km) anthropogenic carbonaceous aerosol emission inventory for Europe. The inventory indicated that about half of the total PM2.5 emission in Europe is carbonaceous aerosol and identified RWC as the largest organic aerosol source in Europe. The inventory was partly based on national reported PM emissions. Use of this organic aerosol inventory as input for two chemical transport models (CTMs), PMCAMx and EMEP MSC-W, revealed major underestimations of organic aerosol in winter time, especially for regions dominated by RWC. Interestingly, this was not universal but appeared to differ by country. In the present study we constructed a revised bottom-up emission inventory for RWC accounting for the semivolatile components of the emissions. The revised RWC emissions are higher than those in the previous inventory by a factor of 2-3 but with substantial inter-country variation. The new emission inventory served as input for the CTMs and a substantially improved agreement between measured and predicted organic aerosol was found. The revised RWC inven-tory improves the model-calculated organic aerosol significantly. Comparisons to Scandinavian source apportionment studies also indicate substantial improvements in the modelled wood-burning component of organic aerosol. This suggests that primary organic aerosol emission inventories need to be revised to include the semivolatile organic aerosol that is formed almost instantaneously due to dilution and cooling of the flue gas or exhaust. Since RWC is a key source of fine PM in Europe, a major revision of the emission estimates as proposed here is likely to influence source-receptor matrices and modelled source apportionment. Since usage of biofuels in small combustion units is a globally significant source, the findings presented here are also relevant for regions outside of Europe.

  • 325. van Loon, M.
    et al.
    Vautard, R.
    Schaap, M.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Bessagnet, B.
    Brandt, J.
    Builtjes, P. J. H.
    Christensen, J. H.
    Cuvelier, C.
    Graff, A.
    Jonson, J. E.
    Krol, M.
    Langner, J.
    Roberts, P.
    Rouil, L.
    Stern, R.
    Tarrason, L.
    Thunis, P.
    Vignati, E.
    White, L.
    Wind, P.
    Evaluation of long-term ozone simulations from seven regional air quality models and their ensemble2007In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 41, no 10, p. 2083-2097Article in journal (Refereed)
    Abstract [en]

    Long-term ozone simulations from seven regional air quality models, the Unified EMEP model, LOTOS-EUROS, CHIMERE, RCG, MATCH, DEHM and TM5, are intercompared and compared to ozone measurements within the framework of the EuroDelta experiment, designed to assess air quality improvement at the European scale in response to emission reduction scenarios for 2020. Modelled ozone concentrations for the year 2001 are evaluated. The models reproduce the main features of the ozone diurnal cycle, but generally overestimate daytime ozone, LOTOS-EUROS and RCG have a more pronounced diurnal cycle variation than observations, while the reverse occurs for TM5. CHIMERE has a large positive bias, which can be explained by a systematic bias in boundary conditions. The other models and the "ensemble model", whose concentrations are by definition averaged over all models, represent accurately the diurnal cycle. The ability of the models to simulate day-to-day daily ozone average or maxima variability is examined by means of percentiles, root mean square errors and correlations. In general, daily maxima are better simulated than daily averages, and summertime concentrations are better simulated than wintertime concentrations. Summertime correlations range between 0.5 and 0.7 for daily averages and 0.6 and 0.8 for daily maxima. Two health-related indicators are used, the number of days of exceedance of the 120 mu g m(-3) threshold for the daily maximal 8-h ozone concentration and the SOMO35. Both are well reproduced in terms of frequency, but the simultaneity of occurrence of exceedance days between observations and simulations is not well captured.

  • 326. van Pul, Addo
    et al.
    Hertel, Ole
    Geels, Camilla
    Dore, Anthony J.
    Massimo, Vieno
    van Jaarsveld, Hans A.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Schaap, Martijn
    Fagerli, Hilde
    Modelling of the Atmospheric Transport and Deposition of Ammonia at a National and Regional Scale2009In: in Atmospheric Ammonia - Detecting emission changes and environmental impacts., Springer, 2009, p. 301-356Chapter in book (Other academic)
  • 327. van Pul, Addo
    et al.
    Reis, Stefan
    Dore, Tony
    Xuejun, Liu
    Hilde, Fagerli
    Geels, Camilla
    Hertel, Ole
    Kruijt Roy, Wichink
    Kryza, Maciej
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Vieno, Massimo
    Ron, Smith
    Eiko, Nemitz
    Modelling the National and Regional Transport and Deposition of Ammonia2009In: Atmospheric Ammonia - Detecting emission changes and environmental impacts., Springer, 2009, p. 409-421Chapter in book (Other academic)
  • 328. Vautard, R.
    et al.
    Schaap, M.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Bessagnet, B.
    Brandt, J.
    Builtjes, P. J. H.
    Christensen, J. H.
    Cuvelier, C.
    Foltescu, Valentin
    SMHI.
    Graff, A.
    Kerschbaumer, A.
    Krol, M.
    Roberts, P.
    Rouil, L.
    Stern, R.
    Tarrason, L.
    Thunis, P.
    Vignati, E.
    Wind, P.
    Skill and uncertainty of a regional air quality model ensemble2009In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 43, no 31, p. 4822-4832Article in journal (Refereed)
    Abstract [en]

    Recently several regional air quality projects were carried out to support the negotiation under the Clean Air For Europe (CAFE) programme by predicting the impact of emission control policies with an ensemble of models. Within these projects, CITYDELTA and EURODELTA, the fate of air quality at the scale of European cities or that of the European continent was studied using several models. In this article we focus on the results of EURODELTA. The predictive skill of the ensemble of models is described for ozone, nitrogen dioxide and secondary inorganic compounds, and the uncertainty in air quality modelling is examined through the model ensemble spread of concentrations. For ozone daily maxima the ensemble spread origin differs from one region to another. In the neighbourbood of cities or in mountainous areas the spread of predicted values does not span the range of observed data, due to poorly resolved emissions or complex-terrain meteorology. By contrast in Atlantic and North Sea coastal areas the spread of predicted values is found to be larger than the observations. This is attributed to large differences in the boundary conditions used in the different models. For NO2 daily averages the ensemble spread is generally too small compared with observations. This is because models miss highest values occurring in stagnant meteorology in stable boundary layers near cities. For secondary particulate matter compounds the simulated concentration spread is more balanced, observations falling nearly equiprobably within the ensemble, and the spread originates both from meteorology and aerosol chemistry and thermodynamics. (C) 2008 Published by Elsevier Ltd.

  • 329. Vautard, R.
    et al.
    Van Loon, M.
    Schaap, M.
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Bessagnet, B.
    Brandt, J.
    Builtjes, P. J. H.
    Christensen, J. H.
    Cuvelier, C.
    Graff, A.
    Jonson, J. E.
    Krol, M.
    Langner, Joakim
    SMHI, Research Department, Air quality.
    Roberts, P.
    Rouil, L.
    Stern, R.
    Tarrason, L.
    Thunis, P.
    Vignati, E.
    White, L.
    Wind, P.
    Is regional air quality model diversity representative of uncertainty for ozone simulation?2006In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 33, no 24, article id L24818Article in journal (Refereed)
    Abstract [en]

    We examine whether seven state-of-the-art European regional air quality models provide daily ensembles of predicted ozone maxima that encompass observations. Using tools borrowed from the evaluation of ensemble weather forecasting, we analyze statistics of simulated ensembles of ozone daily maxima over an entire summer season. Although the model ensemble overestimates ozone, the distribution of simulated concentrations is representative of the uncertainty. The spread of simulations is due to random fluctuations resulting from differences in model formulations and input data, but also to the spread between individual model systematic biases. The ensemble average skill increases as the spread decreases. The skill of the ensemble in giving probabilistic predictions of threshold exceedances is also demonstrated. These results allow for optimism about the ability of this ensemble to simulate the uncertainty of the impact of emission control scenarios.

  • 330. Veihelmann, B
    et al.
    Nousiainen, T
    Kahnert, Michael
    SMHI, Research Department, Air quality.
    van der Zande, W J
    Light scattering by small feldspar particles simulated using the Gaussian random sphere geometry2006In: Journal of Quantitative Spectroscopy and Radiative Transfer, ISSN 0022-4073, E-ISSN 1879-1352, Vol. 100, no 1-3, p. 393-405Article in journal (Refereed)
    Abstract [en]

    The single-scattering properties of Gaussian random spheres are calculated using the discrete dipole approximation. The ensemble of model particles is assumed to be representative for a feldspar dust sample that is characteristic for weakly absorbing irregularly shaped mineral aerosol. The morphology of Gaussian random spheres is modeled based on a statistical shape analysis using microscope images of the dust sample. The size distribution of the dust sample is based on a particle sizing experiment. The refractive index of feldspar is estimated using literature values. All input parameters used in the light scattering simulations are thus obtained in an objective way based on the true properties of the mineral sample. The orientation-averaged and ensemble-averaged scattering matrices and cross sections of the Gaussian random spheres are compared with light scattering simulations using spheroidal shape models which have been shown to be applicable to the feldspar sample. The Gaussian random sphere model and the spheroidal shape model are assessed using the measured scattering matrix of the feldspar dust sample as a reference. Generally, the spheroidal model with strongly elongated prolate and strongly flattened oblate shapes agrees better with the measurement than the Gaussian random sphere model. In contrast, some features that are characteristic for light scattering by truly irregular mineral dust particles are rendered best by the Gaussian random sphere model; these features include the flat shape of the phase function and a minimum in the scattering matrix element F-22/F-11 as a function of the scattering angle. (c) 2005 Elsevier Ltd. All rights reserved.

  • 331. Vivanco, Marta G.
    et al.
    Theobald, Mark R.
    Garcia-Gomez, Hector
    Luis Garrido, Juan
    Prank, Marje
    Aas, Wenche
    Adani, Mario
    Alyuz, Ummugulsum
    Andersson, Camilla
    SMHI, Research Department, Air quality.
    Bellasio, Roberto
    Bessagnet, Bertrand
    Bianconi, Roberto
    Bieser, Johannes
    Brandt, Jurgen
    Briganti, Gino
    Cappelletti, Andrea
    Curci, Gabriele
    Christensen, Jesper H.
    Colette, Augustin
    Couvidat, Florian
    Cuvelier, Cornelis
    D'Isidoro, Massimo
    Flemming, Johannes
    Fraser, Andrea
    Geels, Camilla
    Hansen, Kaj M.
    Hogrefe, Christian
    Im, Ulas
    Jorba, Oriol
    Kitwiroon, Nutthida
    Manders, Astrid
    Mircea, Mihaela
    Otero, Noelia
    Pay, Maria-Teresa
    Pozzoli, Luca
    Solazzo, Efisio
    Tsyro, Svetlana
    Unal, Alper
    Wind, Peter
    Galmarini, Stefano
    Modeled deposition of nitrogen and sulfur in Europe estimated by 14 air quality model systems: evaluation, effects of changes in emissions and implications for habitat protection2018In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 18, no 14, p. 10199-10218Article in journal (Refereed)
  • 332. Wang, Zifa
    et al.
    Xie, Fuying
    Sakurai, T.
    Ueda, H.
    Han, Zhiwei
    Carmichael, G. R.
    Streets, D.
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Holloway, T.
    Hayami, H.
    Kajino, M.
    Thongboonchoo, N.
    Bennet, Cecilia
    SMHI, Research Department, Air quality.
    Park, S. U.
    Fung, C.
    Chang, A.
    Sartelet, K.
    Amann, M.
    MICS-Asia II: Model inter-comparison and evaluation of acid deposition2008In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 42, no 15, p. 3528-3542Article in journal (Refereed)
    Abstract [en]

    This paper focuses on the comparison of chemical deposition of eight regional chemical models used in Model Inter-Comparison Study for Asia (MICS-Asia) II. Monthly-mean depositions of chemical species simulated by these models, including dry deposition of SO(2), HNO(3), NH(3), Sulfate, nitrate and ammonium and wet deposition of SO(4)(2-), NO(3)(-) and NH(4)(+), have been provided for four periods (March, July, December 2001 and March 2002) in this work. Observations at 37 sites of the Acid Deposition Monitoring Network in East Asia (EANET) are compared with SO(4)(2-), NO(3)(-) and NH(4)(+) wet deposition model results. Significant correlations appeared between the observation and computed ensemble mean of participant models. Also, differences among modeled sulfur and nitrogen dry depositions have been studied at the EANET sites. Based on the analysis of acid deposition for various species from different models, total depositions of sulfur (SO(2) and sulfate) and nitrogen (nitrate and ammonium) have been evaluated as the ensemble mean of the eight models. In general, all models capture the observed spatial distribution' of sulfur and nitrogen deposition, although the absolute values may differ from measurements. High deposition often occurs in eastern China, Japan, the Republic of Korea, Thailand, Vietnam, Philippines and other parts of Southeast Asia. The magnitude of model bias is quite large for many of the models. In examining the reasons for model-measurement disagreement, we find that differences in chemical processes, deposition parameterization, and modeled precipitation are the main reasons for large model disparities. (C) 2008 Elsevier Ltd. All rights reserved.

  • 333. Watson, Laura
    et al.
    Lacressonniere, Gwendoline
    Gauss, Michael
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Andersson, Camilla
    SMHI, Research Department, Air quality.
    Josse, Beatrice
    Marecal, Virginie
    Nyiri, Agnes
    Sobolowski, Stefan
    Siour, Guillaume
    Szopa, Sophie
    Vautard, Robert
    Impact of emissions and+2 degrees C climate change upon future ozone and nitrogen dioxide over Europe2016In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 142, p. 271-285Article in journal (Refereed)
  • 334. Watson, Laura
    et al.
    Lacressonniere, Gwendoline
    Gauss, Michael
    Engardt, Magnuz
    SMHI, Research Department, Air quality.
    Andersson, Camilla
    SMHI, Research Department, Air quality.
    Josse, Beatrice
    Marecal, Virginie
    Nyiri, Agnes
    Sobolowski, Stefan
    Siour, Guillaume
    Vautard, Robert
    The impact of meteorological forcings on gas phase air pollutants over Europe2015In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 119, p. 240-257Article in journal (Refereed)
    Abstract [en]

    The impact of meteorological forcings on gas phase air pollutants (ozone and nitrogen dioxide) over Europe was studied using four offline chemistry transport models (CTMs) as part of the IMPACT2C project. This study uses long (20- and 30-year) simulations to evaluate the present-day performance of the CTMs, which is a necessary first step before undertaking any analysis of future air quality impacts. Two sets of meteorological forcings were used for each model: reanalysis of past observation data (ERA-Interim) and Global Climate Model (GCM) output. The results for the simulations forced by reanalysis data were assessed in relation to AirBase v7 measurement data, and it was determined that all four models slightly overpredict annual O-3 values (mean biases range between 0.7 and 6.6 ppb) and three out of the four models underpredict observed annual NO2 (mean biases range between -3.1 and -5.2 ppb). The simulations forced by climate models result in spatially averaged monthly concentrations of O-3 that are generally between 0 and 5 ppb higher than the values obtained from simulations forced by reanalysis data; therefore it was concluded that the use of climate models introduces an additional bias to the results, but this bias tends not to be significant in the majority of cases. The bias in O-3 results appears to be correlated mainly to differences in temperature and boundary layer height between the two types of simulations, whereas the less significant bias in NO2 is negatively correlated to temperature and boundary layer height. It is also clear that the selection of chemical boundary conditions is an important factor in determining the variability of O-3 model results. These results will be used as a baseline for the interpretation of future work, which will include an analysis of future climate scenarios upon European air quality. (C) 2015 Elsevier Ltd. All rights reserved.

  • 335.
    Wern, Lennart
    et al.
    SMHI, Core Services.
    Kindell, Sven
    SMHI, Professional Services.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Luktberäkningar för AB ELMO i Flen1986Report (Other academic)
  • 336.
    Wern, Lennart
    et al.
    SMHI, Core Services.
    Omstedt, Gunnar
    SMHI, Research Department, Air quality.
    Spridningsberäkningar för Volvos planerade bilfabrik i Uddevalla - energicentralen1985Report (Other academic)
  • 337. Willers, Saskia M.
    et al.
    Eriksson, Charlotta
    Gidhagen, Lars
    SMHI, Research Department, Air quality.
    Nilsson, Mats E.
    Pershagen, Goran
    Bellander, Tom
    Fine and coarse particulate air pollution in relation to respiratory health in Sweden2013In: European Respiratory Journal, ISSN 0903-1936, E-ISSN 1399-3003, Vol. 42, no 4, p. 924-934Article in journal (Refereed)
    Abstract [en]

    Health effects have repeatedly been associated with residential levels of air pollution. However, it is difficult to disentangle effects of long-term exposure to locally generated and long-range transported pollutants, as well as to exhaust emissions and wear particles from road traffic. We aimed to investigate effects of exposure to particulate matter fractions on respiratory health in the Swedish adult population, using an integrated assessment of sources at different geographical scales. The study was based on a nationwide environmental health survey performed in 2007, including 25 851 adults aged 18-80 years. Individual exposure to particulate matter at residential addresses was estimated by dispersion modelling of regional, urban and local sources. Associations between different size fractions or source categories and respiratory outcomes were analysed using multiple logistic regression, adjusting for individual and contextual confounding. Exposure to locally generated wear particles showed associations for blocked nose or hay fever, chest tightness or cough, and restricted activity days with odds ratios of 1.5-2 per 10-mu g.m(-3) increase. Associations were also seen for locally generated combustion particles, which disappeared following adjustment for exposure to wear particles. In conclusion, our data indicate that long-term exposure to locally generated road wear particles increases the risk of respiratory symptoms in adults.

  • 338. Willers, Saskia M.
    et al.
    Eriksson, Charlotta
    Gidhagen, Lars
    SMHI, Research Department, Air quality.
    Nilsson, Mats E.
    Pershagen, Goran
    Bellander, Tom
    Traffic Related Air Pollution and Respiratory Health in Sweden: The Roadside Study2009In: EPIDEMIOLOGY, ISSN 1044-3983, Vol. 20, no 6, p. S29-S30Article in journal (Other academic)
  • 339. Yttri, Karl Espen
    et al.
    Simpson, David
    Bergström, Robert
    SMHI, Research Department, Air quality.
    Kiss, Gyula
    Szidat, Sonke
    Ceburnis, Darius
    Eckhardt, Sabine
    Hueglin, Christoph
    Nojgaard, Jacob Kleno
    Perrino, Cinzia
    Pisso, Ignazio
    Prevot, Andre Stephan Henry
    Putaud, Jean-Philippe
    Spindler, Gerald
    Vana, Milan
    Zhang, Yan-Lin
    Aas, Wenche
    The EMEP Intensive Measurement Period campaign, 2008-2009: characterizing carbonaceous aerosol at nine rural sites in Europe2019In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 19, no 7, p. 4211-4233Article in journal (Refereed)
  • 340. Yurkin, Maxim A.
    et al.
    Kahnert, Michael
    SMHI, Research Department, Air quality.
    Light scattering by a cube: Accuracy limits of the discrete dipole approximation and the T-matrix method2013In: Journal of Quantitative Spectroscopy and Radiative Transfer, ISSN 0022-4073, E-ISSN 1879-1352, Vol. 123, p. 176-183Article in journal (Refereed)
    Abstract [en]

    We simulated light-scattering by small and wavelength-sized cubes with three largely different values of the refractive index using the discrete dipole approximation (DDA) and the T-matrix method. Our main goal was to push the accuracy of both methods to the limit. For the DDA we used an earlier developed extrapolation technique based on simulation results for different levels of discretization. For the T-matrix method we developed a procedure to estimate a confidence range for the simulated value, using results for different values of the truncation index (number of multipoles). In most cases this confidence range was reliable, enclosing the corresponding DDA result. We present benchmark results by both methods, including estimated uncertainties, for selected integral and angle-resolved scattering quantities. Estimated relative uncertainties of the DDA result are unprecedentedly small (from 10(-7) to 10(-3)), while relative differences between the T-matrix and DDA results are larger (from 10(-4) to 0.2) in accordance with estimated T-matrix uncertainties. (C) 2012 Elsevier Ltd. All rights reserved.

  • 341. Zunckel, M
    et al.
    Robertson, Lennart
    SMHI, Research Department, Air quality.
    Tyson, P D
    Rodhe, H
    Modelled transport and deposition of sulphur over Southern Africa2000In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 34, no 17, p. 2797-2808Article in journal (Refereed)
    Abstract [en]

    Ambient SO2 concentrations and atmospheric deposition of sulphur resulting from emissions on the industrialised highveld region of South Africa are estimated using the multi-scale atmospheric transport and chemistry (MATCH) modelling system, developed at the Swedish Meteorological and Hydrological Institute (SMHI), and compared with an inferential model driven by measured input quantities. Modelled SO, concentrations on the central highveld mostly range between 10 and 50 ppb, exceeding 50 ppb in source areas. Dry deposition rates for sulphur exhibit a similar spatial pattern to the ambient SO2 concentrations and both are consistent with synoptic-scale transport patterns. Maximum dry deposition rates for sulphur of more than 10 kg S ha(-1) a(-1) occur over the central highveld with a well-defined gradient decreasing away from the source region. Despite the significant differences in modelling approaches, the estimates of dry deposition provided by MATCH are in reasonable agreement with those of the inferential model. The maximum modelled wet deposition rates occur over the South African highveld and its periphery and range between 1 and 5 kg S ha(-1) a(-1) and compare favourably with measurements from an acid rain network. Wet deposition generally exceed dry deposition on the highveld and the adjacent areas except in the central highveld source region. Over the drier western half of South Africa MATCH-modelled dry and wet deposition rates are again similar and are less that 1 kg S ha(-1) a(-1). Wet deposition exceeds dry in the higher rainfall regions along the south and east coasts of South Africa. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.

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