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Sökning: WFRF:(Kristensson Adam) > Eriksson Axel

  • Resultat 1-9 av 9
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1.
  • Ahlberg, Erik, et al. (författare)
  • Measurement report : Black carbon properties and concentrations in southern Sweden urban and rural air-the importance of long-range transport
  • 2023
  • Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 23:5, s. 3051-3064
  • Tidskriftsartikel (refereegranskat)abstract
    • Soot, or black carbon (BC), aerosol is a major climate forcer with severe health effects. The impacts depend strongly on particle number concentration, size and mixing state. This work reports on two field campaigns at nearby urban and rural sites, 65gkm apart, in southern Sweden during late summer 2018. BC was measured using a single-particle soot photometer (SP2) and Aethalometers (AE33). Differences in BC concentrations between the sites are driven primarily by local traffic emissions. Equivalent and refractory BC mass concentrations at the urban site were on average a factor 2.2 and 2.5, with peaks during rush hour up to a factor g1/44, higher than the rural background levels. The number fraction of particles containing a soot core was significantly higher in the city. BC particles at the urban site were on average smaller by mass and had less coating owing to fresh traffic emissions. The organic components of the fresh traffic plumes were similar in mass spectral signature to hydrocarbon-like organic aerosol (HOA), commonly associated with traffic. Despite the intense local traffic (g1/4g30g000 vehicles passing per day), PM1, including organic aerosol, was dominated by aged continental air masses even at the curbside site. The fraction of thickly coated particles at the urban site was highly correlated with the mass concentrations of all measured chemical species of PM1, consistent with aged, internally mixed aerosol. Trajectory analysis for the whole year showed that air masses arriving at the rural site from eastern Europe contained approximately double the amount of BC compared to air masses from western Europe. Furthermore, the largest regional emissions of BC transported to the rural site, from the Malmö-Copenhagen urban area, are discernible above background levels only when precipitation events are excluded. We show that continental Europe and not the Malmö-Copenhagen region is the major contributor to the background BC mass concentrations in southern Sweden.
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2.
  • Ahlberg, Erik, et al. (författare)
  • No particle mass enhancement from induced atmospheric ageing at a rural site in northern Europe
  • 2019
  • Ingår i: Atmosphere. - : MDPI AG. - 2073-4433. ; 10:7
  • Tidskriftsartikel (refereegranskat)abstract
    • A large portion of atmospheric aerosol particles consists of secondary material produced by oxidation reactions. The relative importance of secondary organic aerosol (SOA) can increase with improved emission regulations. A relatively simple way to study potential particle formation in the atmosphere is by using oxidation flow reactors (OFRs) which simulate atmospheric ageing. Here we report on the first ambient OFR ageing experiment in Europe, coupled with scanning mobility particle sizer (SMPS), aerosol mass spectrometer (AMS) and proton transfer reaction (PTR)-MS measurements. We found that the simulated ageing did not produce any measurable increases in particle mass or number concentrations during the two months of the campaign due to low concentrations of precursors. Losses in the reactor increased with hydroxyl radical (OH) exposure and with increasing difference between ambient and reactor temperatures, indicating fragmentation and evaporation of semivolatile material.
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3.
  • Ahlberg, Erik, et al. (författare)
  • Secondary organic aerosol from VOC mixtures in an oxidation flow reactor
  • 2017
  • Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 161, s. 210-220
  • Tidskriftsartikel (refereegranskat)abstract
    • The atmospheric organic aerosol is a tremendously complex system in terms of chemical content. Models generally treat the mixtures as ideal, something which has been questioned owing to model-measurement discrepancies. We used an oxidation flow reactor to produce secondary organic aerosol (SOA) mixtures containing oxidation products of biogenic (α-pinene, myrcene and isoprene) and anthropogenic (m-xylene) volatile organic compounds (VOCs). The resulting volume concentration and chemical composition was measured using a scanning mobility particle sizer (SMPS) and a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), respectively. The SOA mass yield of the mixtures was compared to a partitioning model constructed from single VOC experiments. The single VOC SOA mass yields with no wall-loss correction applied are comparable to previous experiments. In the mixtures containing myrcene a higher yield than expected was produced. We attribute this to an increased condensation sink, arising from myrcene producing a significantly higher number of nucleation particles compared to the other precursors. Isoprene did not produce much mass in single VOC experiments but contributed to the mass of the mixtures. The effect of high concentrations of isoprene on the OH exposure was found to be small, even at OH reactivities that previously have been reported to significantly suppress OH exposures in oxidation flow reactors. Furthermore, isoprene shifted the particle size distribution of mixtures towards larger sizes, which could be due to a change in oxidant dynamics inside the reactor.
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4.
  • Ausmeel, Stina, et al. (författare)
  • Methods for identifying aged ship plumes and estimating contribution to aerosol exposure downwind of shipping lanes
  • 2019
  • Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 12:8, s. 4479-4493
  • Tidskriftsartikel (refereegranskat)abstract
    • Ship traffic is a major source of aerosol particles, particularly near shipping lanes and harbours. In order to estimate the contribution to exposure downwind of a shipping lane, it is important to be able to measure the ship emission contribution at various distances from the source. We report on measurements of atmospheric particles 7-20 km downwind of a shipping lane in the Baltic Sea Sulfur Emission Control Area (SECA) at a coastal location in southern Sweden during a winter and a summer campaign. Each ship plume was linked to individual ship passages using a novel method based on wind field data and automatic ship identification system data (AIS), where varying wind speeds and directions were applied to calculate a plume trajectory. In a situation where AIS data are not matching measured plumes well or if AIS data are missing, we provide an alternative method with particle number concentration data. The shipping lane contribution to the particle number concentration in Falsterbo was estimated by subtracting background concentrations from the ship plume concentrations, and more than 150 plumes were analysed. We have also extrapolated the contribution to seasonal averages and provide recommendations for future similar measurements. Averaged over a season, the contribution to particle number concentration was about 18 % during the winter and 10 % during the summer, including those periods with wind directions when the shipping lane was not affecting the station. The corresponding contribution to equivalent black carbon was 1.4 %..
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5.
  • Ausmeel, Stina, et al. (författare)
  • Ship plumes in the Baltic Sea Sulfur Emission Control Area: chemical characterization and contribution to coastal aerosol concentrations
  • 2020
  • Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7324. ; 20:15, s. 9135-9151
  • Tidskriftsartikel (refereegranskat)abstract
    • In coastal areas, there is increased concern aboutemissions from shipping activities and the associated impacton air quality. We have assessed the ship aerosol propertiesand the contribution to coastal particulate matter (PM) andnitrogen dioxide (NO2) levels by measuring ship plumes inambient conditions at a site in southern Sweden, within a SulfurEmission Control Area. Measurements took place duringa summer and a winter campaign, 10 km downwind ofa major shipping lane. Individual ships showed large variabilityin contribution to total particle mass, organics, sulfate,and NO2. The average emission contribution of theshipping lane was 2913 and 3720 ngm?3 to PM0:5,188 and 3419 ngm?3 to PM0:15, and 1:210:57 and1:110:61 μgm?3 to NO2, during winter and summer, respectively.Sulfate and organics dominated the particle massand most plumes contained undetectable amounts of equivalentblack carbon (eBC). The average eBC contribution was3:51:7 ngm?3 and the absorption Ångström exponent wasclose to 1. Simulated ageing of the ship aerosols using anoxidation flow reactor showed that on a few occasions, therewas an increase in sulfate and organic mass after photochemicalprocessing of the plumes. However, most plumes did notproduce measurable amounts of secondary PM upon simulatedageing.
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6.
  • Kristensson, Adam, et al. (författare)
  • Source contributions to rural carbonaceous winter aerosol in North-Eastern Poland
  • 2020
  • Ingår i: Atmosphere. - : MDPI AG. - 2073-4433. ; 11:3
  • Tidskriftsartikel (refereegranskat)abstract
    • Concentrations of aerosol particles in Poland and their sources are rarely discussed in peer-reviewed journal articles despite serious air quality issues. A source apportionment of carbonaceous aerosol particles was performed during winter at a rural background environment field site in north-eastern Poland. Data were used of light absorption at seven wavelengths and levoglucosan concentrations along existing monitoring of PM2.5, organic carbon and elemental carbon (OC/EC) at the Diabla Gora EMEP monitoring site between January 17 and March 19 during the EMEP intensive winter campaign of 2018. Average PM2.5, OC, EC, equivalent black carbon (eBC) and levoglucosan concentrations and standard deviations amounted to 18.5 ± 9.3, 4.5 ± 2.5, 0.57 ± 0.28, 1.04 ± 0.62 and 0.134 ± 0.084 μg m-3 respectively. Various tools for source apportionment were used to obtain a source contribution to carbonaceous matter (CM) with three components. The wood combustion source component contributed 1.63 μg m-3 (21%), domestic coal combustion 3.3 μg m-3 (41%) and road transport exhaust 2.9 μg m-3 (38%). Similar levels and temporal variability were found for the nearby Lithuanian site of Preila, corroborating the Polish results.
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8.
  • Roldin, Pontus, et al. (författare)
  • Aerosol ageing in an urban plume - implication for climate
  • 2011
  • Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7324. ; 11:12, s. 5897-5915
  • Tidskriftsartikel (refereegranskat)abstract
    • The climate effects downwind of an urban area resulting from gaseous and particulate emissions within the city are as yet inadequately quantified. The aim of this work was to estimate these effects for Malmo city in southern Sweden (population 280 000). The chemical and physical particle properties were simulated with a model for Aerosol Dynamics, gas phase CHEMistry and radiative transfer calculations (ADCHEM) following the trajectory movement from upwind of Malmo, through the urban background environment and finally tens and hundreds of kilometers downwind of Malmo. The model results were evaluated using measurements of the particle number size distribution and chemical composition. The total particle number concentration 50 km (similar to 3 h) downwind, in the center of the Malmo plume, is about 3700 cm(-3) of which the Malmo contribution is roughly 30%. Condensation of nitric acid, ammonium and to a smaller extent oxidized organic compounds formed from the emissions in Malmo increases the secondary aerosol formation with a maximum of 0.7-0.8 mu gm(-3) 6 to 18 h downwind of Malmo. The secondary mass contribution dominates over the primary soot contribution from Malmo already 3 to 4 h downwind of the emission sources and contributes to an enhanced total surface direct or indirect aerosol shortwave radiative forcing in the center of the urban plume ranging from -0.3 to -3.3 Wm(-2) depending on the distance from Malmo, and the specific cloud properties.
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