54 research outputs found
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Cloud water composition during HCCT-2010: Scavenging efficiencies, solute concentrations, and droplet size dependence of inorganic ions and dissolved organic carbon
Cloud water samples were taken in September/October 2010 at Mt. SchmĂŒcke in a rural, forested area in Germany during the Lagrange-type Hill Cap Cloud Thuringia 2010 (HCCT-2010) cloud experiment. Besides bulk collectors, a three-stage and a five-stage collector were applied and samples were analysed for inorganic ions (SO42â,NO3â, NH4+, Clâ, Na+, Mg2+, Ca2+, K+), H2O2 (aq), S(IV), and dissolved organic carbon (DOC). Campaign volume-weighted mean concentrations were 191, 142, and 39 ”mol Lâ1 for ammonium, nitrate, and sulfate respectively, between 4 and 27 ”mol Lâ1 for minor ions, 5.4 ”mol Lâ1 for H2O2 (aq), 1.9 ”mol Lâ1 for S(IV), and 3.9 mgC Lâ1 for DOC. The concentrations compare well to more recent European cloud water data from similar sites. On a mass basis, organic material (as DOC Ă 1.8) contributed 20â40 % (event means) to total solute concentrations and was found to have non-negligible impact on cloud water acidity. Relative standard deviations of major ions were 60â66 % for solute concentrations and 52â80 % for cloud water loadings (CWLs). The similar variability of solute concentrations and CWLs together with the results of back-trajectory analysis and principal component analysis, suggests that concentrations in incoming air masses (i.e. air mass history), rather than cloud liquid water content (LWC), were the main factor controlling bulk solute concentrations for the cloud studied. Droplet effective radius was found to be a somewhat better predictor for cloud water total ionic content (TIC) than LWC, even though no single explanatory variable can fully describe TIC (or solute concentration) variations in a simple functional relation due to the complex processes involved. Bulk concentrations typically agreed within a factor of 2 with co-located measurements of residual particle concentrations sampled by a counterflow virtual impactor (CVI) and analysed by an aerosol mass spectrometer (AMS), with the deviations being mainly caused by systematic differences and limitations of the approaches (such as outgassing of dissolved gases during residual particle sampling). Scavenging efficiencies (SEs) of aerosol constituents were 0.56â0.94, 0.79â0.99, 0.71â98, and 0.67â0.92 for SO42â, NO3â, NH4+, and DOC respectively when calculated as event means with in-cloud data only. SEs estimated using data from an upwind site were substantially different in many cases, revealing the impact of gas-phase uptake (for volatile constituents) and mass losses across Mt. SchmĂŒcke likely due to physical processes such as droplet scavenging by trees and/or entrainment. Drop size-resolved cloud water concentrations of major ions SO42â, NO3â, and NH4+ revealed two main profiles: decreasing concentrations with increasing droplet size and âUâ shapes. In contrast, profiles of typical coarse particle mode minor ions were often increasing with increasing drop size, highlighting the importance of a species' particle concentration size distribution for the development of size-resolved solute concentration patterns. Concentration differences between droplet size classes were typicallyâŻ< 2 for major ions from the three-stage collector and somewhat more pronounced from the five-stage collector, while they were much larger for minor ions. Due to a better separation of droplet populations, the five-stage collector was capable of resolving some features of solute size dependencies not seen in the three-stage data, especially sharp concentration increases (up to a factor of 5â10) in the smallest droplets for many solutes
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Source apportionment and impact of long-range transport on carbonaceous aerosol particles in central Germany during HCCT-2010
The identification of different sources of the carbonaceous aerosol (organics and black carbon) was investigated at a mountain forest site located in central Germany from September to October 2010 to characterize incoming air masses during the Hill Cap Cloud Thuringia 2010 (HCCT-2010) experiment. The near-PM1 chemical composition, as measured by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), was dominated by organic aerosol (OA; 41â%) followed by sulfate (19â%) and nitrate (18â%). Source apportionment of the OA fraction was performed using the multilinear engine (ME-2) approach, resulting in the identification of the following five factors: hydrocarbon-like OA (HOA; 3â% of OA mass), biomass burning OA (BBOA; 13â%), semi-volatile-like OA (SV-OOA; 19â%), and two oxygenated OA (OOA) factors. The more oxidized OOA (MO-OOA, 28â%) was interpreted as being influenced by aged, polluted continental air masses, whereas the less oxidized OOA (LO-OOA, 37â%) was found to be more linked to aged biogenic sources. Equivalent black carbon (eBC), measured by a multi-angle absorption photometer (MAAP) represented 10â% of the total particulate matter (PM). The eBC was clearly associated with HOA, BBOA, and MO-OOA factors (all together R2=0.83). Therefore, eBC's contribution to each factor was achieved using a multi-linear regression model. More than half of the eBC (52â%) was associated with long-range transport (i.e., MO-OOA), whereas liquid fuel eBC (35â%) and biomass burning eBC (13â%) were associated with local emissions, leading to a complete apportionment of the carbonaceous aerosol. The separation between local and transported eBC was well supported by the mass size distribution of elemental carbon (EC) from Berner impactor samples. Air masses with the strongest marine influence, based on back trajectory analysis, corresponded with a low particle mass concentration (6.4â7.5â”gâmâ3) and organic fraction (â30â%). However, they also had the largest contribution of primary OA (HOA â 4â% and BBOA 15â%â20â%), which was associated with local emissions. Continental air masses had the highest mass concentration (11.4â12.6â”gâmâ3), and a larger fraction of oxygenated OA (â45â%) indicated highly processed OA. The present results emphasize the key role played by long-range transport processes not only in the OA fraction but also in the eBC mass concentration and the importance of improving our knowledge on the identification of eBC sources
AbschĂ€tzung der gröĂenaufgelösten Partikelkonzentration und -zusammensetzung anhand wetterlagenorientierter experimenteller Messungen
Der Bericht "AbschĂ€tzung der gröĂenaufgelösten Partikelkonzentration und -zusammensetzung anhand wetterlagenorientierter experimenteller Messungen" reprĂ€sentiert das REGKLAM-Produkt 2.2b. Auf der Grundlage von Experimenten wurde die heutige Situation analysiert und Szeanarien fĂŒr einen Temperaturanstiegt sowie fĂŒr eine Ănderung der Anströmcharakteristik erarbeitet. Da die PM10-Massenkonzentrationen bereits heute Grenzwerte ĂŒberschreiten und im Rahmen der klimatischen VerĂ€nderung nicht mit einer wesentlichen Abnahme zu rechnen ist, bleibt es auch zukĂŒnftig eine wichtige Herausforderung, die Emissionen von Partikeln und deren VorlĂ€ufersubstanzen sowohl in der Stadt als auch in der groĂrĂ€umigen Umgebung zu vermeiden
Umweltzone Leipzig: Messtechnische Begleitung der EinfĂŒhrung der Umweltzone in der Stadt Leipzig: Teil 1: Ausgangsbeurteilung der Immissionssituation im Jahr 2010vor der EinfĂŒhrung der Umweltzone
Zur EinfĂŒhrung der Umweltzone in Leipzig werden begleitende Messungen an 12 Messstationen durchgefĂŒhrt. Neben den gesetzlich vorgegebenen Schadstoffen werden SondermessgröĂen wie RuĂ und die Anzahl ultrafeiner Partikel ĂŒberwacht.
Der erste Teil der Berichterstattung dokumentiert die Messergebnisse im Jahr 2010 vor EinfĂŒhrung der Umweltzone. Er bildet die Ausgangssituation zur Beurteilung der Wirksamkeit der Umweltzone ab. Dargestellt ist auch das Minderungspotenzial einer Umweltzone, das an fĂŒnf verkehrsnahen Messstellen in Leipzig und Dresden erstmals ermittelt wurde. Danach können etwa fĂŒnf bis zehn PM10-GrenzwertĂŒberschreitungstage vermieden werden
Zusatzbelastung aus Holzheizungen
Die Schriftenreihe informiert ĂŒber das AusmaĂ der Luftbelastung durch Holzheizungen in einem kleinen Ort. Die gesetzlichen Grenzwerte fĂŒr die LuftqualitĂ€t wurden nicht ĂŒberschritten. Die Zusatzbelastung im Winter insbesondere bei ultrafeinen Partikeln, RuĂ und dem als krebserzeugend eingestuften Benzo(a)pyren bedeutet eine nicht unerhebliche Verschlechterung der LuftqualitĂ€t. Die Ergebnisse zu den Konzentrationen von Dioxinen und Furanen im Staubniederschlag sind in einem gesonderten Bericht zusammengefasst.
Der Bericht richtet sich an Fachbehörden, Wissenschaft und interessierte BĂŒrger.
Redaktionsschluss: 09.04.202
Source apportionment and impact of long-range transport on carbonaceous aerosol particles in central Germany during HCCT-2010
The identification of different sources of the carbonaceous aerosol (organics and black carbon) was investigated at a mountain forest site located in central Germany from September to October 2010 to characterize incoming air masses during the Hill Cap Cloud Thuringia 2010 (HCCT-2010) experiment. The near-PM1 chemical composition, as measured by a high-resolution time-offlight aerosol mass spectrometer (HR-ToF-AMS), was dominated by organic aerosol (OA; 41 %) followed by sulfate (19 %) and nitrate (18 %). Source apportionment of the OA fraction was performed using the multilinear engine (ME-2) approach, resulting in the identification of the following five factors: hydrocarbon-like OA (HOA; 3% of OA mass), biomass burning OA (BBOA; 13 %), semi-volatilelike OA (SV-OOA; 19 %), and two oxygenated OA (OOA) factors. The more oxidized OOA (MO-OOA, 28 %) was interpreted as being influenced by aged, polluted continental air masses, whereas the less oxidized OOA (LO-OOA, 37 %) was found to be more linked to aged biogenic sources. Equivalent black carbon (eBC), measured by a multi-angle absorption photometer (MAAP) represented 10% of the total particulate matter (PM). The eBC was clearly associated with HOA, BBOA, and MO-OOA factors (all together R-2=0 :83). Therefore, eBC\u27s contribution to each factor was achieved using a multi-linear regression model. More than half of the eBC (52 %) was associated with long-range transport (i.e., MO-OOA), whereas liquid fuel eBC (35 %) and biomass burning eBC (13 %) were associated with local emissions, leading to a complete apportionment of the carbonaceous aerosol. The separation between local and transported eBC was well supported by the mass size distribution of elemental carbon (EC) from Berner impactor samples. Air masses with the strongest marine influence, based on back trajectory analysis, corresponded with a low particle mass concentration (6.4-7.5 mu gm(-3)/ and organic fraction (approximate to 30 %). However, they also had the largest contribution of primary OA (HOA approximate to 4% and BBOA 15 %-20 %), which was associated with local emissions. Continental air masses had the highest mass concentration (11.4-12.6 mu gm(-3)), and a larger fraction of oxygenated OA (approximate to 45 %) indicated highly processed OA. The present results emphasize the key role played by long-range transport processes not only in the OA fraction but also in the eBC mass concentration and the importance of improving our knowledge on the identification of eBC sources
Aerosole zur Indikation der LuftqualitĂ€t im Raum Leipzig: KorngröĂendifferenzierte chemisch-physikalische Aerosolcharakterisierung als Indikator der VerĂ€nderung der LuftqualitĂ€t gegenĂŒber 2000 in Leipzig und Sachsen
Der Bericht aus der Luftreinhaltung untersucht die Partikelzusammensetzung in der AuĂenluft. An vier Messorten in und um Leipzig wurden ultrafeine und feine Partikel nach Wetterlagen charakterisiert. Rund 90.000 Einzelanalysen fĂŒhrten zu den Verursachern. Bei östlicher Anströmung im Winter entstanden hohe Feinstaubwerte zu 80 % durch Kohle- und Holzheizungen und SekundĂ€r-Partikel. Dabei lag meist ĂŒberregionaler Ferntransport vor. Verkehrsemissionen dominierten bei westlicher Anströmung. RuĂ, Metalle und polyzyklische Kohlenwasserstoffe reduzierten sich gegenĂŒber 2000 deutlich
The influence of impactor size cut-off shift caused by hygroscopic growth on particulate matter loading and composition measurements
The mass loading and composition of atmospheric particles are important in determining their climate and health effects, and are typically measured by filter sampling. However, particle sampling under ambient conditions can lead to a shift in the size cut-off threshold induced by hygroscopic growth, and the influence of this on measurement of particle loading and composition has not been adequately quantified. Here, we propose a method to assess this influence based on Îș-Köhler theory. A global perspective is presented based on previously reported annual climatological values of hygroscopic properties, meteorological parameters and particle volume size distributions. Measurements at background sites in Europe may be more greatly influenced by the cut-off shift than those from other continents, with a median influence of 10â20% on the total mass of sampled particles. However, the influence is generally much smaller (<7%) at urban sites, and is negligible for dust and particles in the Arctic. Sea-salt particles experience the largest influence (median value âŒ50%), resulting from their large size, high hygroscopicity and the high relative humidity (RH) in marine air-masses. We estimate a difference of âŒ30% in this influence of sea-salt particle sampling between relatively dry (RHâŻ=âŻ60%) and humid (RHâŻ=âŻ90%) conditions. Given the variation in the cut-off shift in different locations and at different times, a consistent consideration of this influence using the approach we introduce here is critical for observational studies of the long-term and spatial distribution of particle loading and composition, and crucial for robust validation of aerosol modules in modelling studies
Umweltzone Leipzig: Messtechnische Begleitung der EinfĂŒhrung der Umweltzone in der Stadt Leipzig: Teil 3: Immissionssituation 2010-2013 und Wirkung der Umweltzone
Die EinfĂŒhrung der Umweltzone in Leipzig wird durch Messungen an Luftmessstationen wissenschaftlich begleitet. Neben den gesetzlich vorgegebenen Schadstoffen werden erstmalig RuĂ und ultrafeine Partikel ĂŒberwacht. Der dritte Teil der Berichterstattung dokumentiert die Ergebnisse bis 2013. Die Umweltzone bewirkte eine beschleunigte Modernisierung der Fahrzeugflotte in der Stadt. In verkehrsnaher AuĂenluft wurden ein deutlicher RĂŒckgang von RuĂ und ultrafeinen Partikeln und eine Stagnation von Stickoxiden nachgewiesen. Erfolgreich wurden die hochtoxischen Bestandteile im Feinstaub gemindert
Umweltzone Leipzig: Messtechnische Begleitung der EinfĂŒhrung der Umweltzone Leipzig: Teil 6 / Abschlussbericht: Immissionssituation von 2010 bis 2016 und Wirkung der Umweltzone auf die straĂennahe LuftqualitĂ€t
Mit EinfĂŒhrung der Umweltzone 2011 erfolgte eine beschleunigte Modernisierung der Fahrzeugflotte in Leipzig gegenĂŒber anderen Regionen in Sachsen. Die Belastung durch Verbrennungspartikel aus der modernisierten Fahrzeugflotte reduzierte sich sehr deutlich. Die Reduzierung war im ersten Jahr der Umweltzone am stĂ€rksten. Nach sechs Jahren wurde eine Minderung fĂŒr die Anzahl der Partikel von 30 bis 200 nm um 74 % und fĂŒr RuĂ-Partikel BC um 59 % nachgewiesen. Dies dokumentiert den Erfolg der Partikelfilter in modernen Dieselfahrzeugen beim realen Fahren in der Stadt. Der hochtoxische Feinstaubanteil in der AuĂenluft und damit das Gesundheitsrisiko der Bevölkerung wurden sehr deutlich gesenkt. Die Umweltzone war damit eine sinnvolle und wirkungsvolle MaĂnahme der Stadtverwaltung.
Gleichzeitig trat keine Verbesserung fĂŒr die Stickstoffoxide durch die modernste Fahrzeugflotte Sachsens ein. Die Dieselfahrzeuge gelten als die Hauptverursacher. Der Misserfolg in der Minderung der Stickoxide moderner Diesel-PKW beim realen Fahren in der Stadt trotz verschĂ€rfter EURO-Abgasnormen wurde dokumentiert. Ăber die tatsĂ€chlichen Emissionen moderner Diesel-PKW wurden BĂŒrger und Stadtverwaltung von Autoherstellern getĂ€uscht
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