Publications (16)0 Total impact
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Article: Introduction to the European Monitoring and Evaluation Programme (EMEP) and observed atmospheric composition change during 1972-2009
Atmospheric Chemistry and Physics. 01/2012; 12(12):5447-5481. -
Article: Effects of relative humidity on aerosol light scattering in the Arctic
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ABSTRACT: Aerosol particles experience hygroscopic growth in the ambient atmosphere. Their optical properties – especially the aerosol light scattering – are therefore strongly dependent on the ambient relative humidity (RH). In-situ light scattering measurements of long-term observations are usually performed under dry conditions (RH>30–40%). The knowledge of this RH effect is of eminent importance for climate forcing calculations or for the comparison of remote sensing with in-situ measurements. This study combines measurements and model calculations to describe the RH effect on aerosol light scattering for the first time for aerosol particles present in summer and fall in the high Arctic. For this purpose, a field campaign was carried out from July to October 2008 at the Zeppelin station in Ny-Ålesund, Svalbard. The aerosol light scattering coefficient σsp(λ) was measured at three distinct wavelengths (λ=450, 550, and 700 nm) at dry and at various, predefined RH conditions between 20% and 95% with a recently developed humidified nephelometer (WetNeph) and with a second nephelometer measuring at dry conditions with an average RH<10% (DryNeph). In addition, the aerosol size distribution and the aerosol absorption coefficient were measured. The scattering enhancement factor f(RH, λ) is the key parameter to describe the RH effect on σsp(λ) and is defined as the RH dependent σsp(RH, λ) divided by the corresponding dry σsp(RHdry, λ). During our campaign the average f(RH=85%, λ=550 nm) was 3.24±0.63 (mean ± standard deviation), and no clear wavelength dependence of f(RH, λ) was observed. This means that the ambient scattering coefficients at RH=85% were on average about three times higher than the dry measured in-situ scattering coefficients. The RH dependency of the recorded f(RH, λ) can be well described by an empirical one-parameter equation. We used a simplified method to retrieve an apparent hygroscopic growth factor g(RH), defined as the aerosol particle diameter at a certain RH divided by the dry diameter, using the WetNeph, the DryNeph, the aerosol size distribution measurements and Mie theory. With this approach we found, on average, g(RH=85%) values to be 1.61±0.12 (mean±standard deviation). No clear seasonal shift of f(RH, λ) was observed during the 3-month period, while aerosol properties (size and chemical composition) clearly changed with time. While the beginning of the campaign was mainly characterized by smaller and less hygroscopic particles, the end was dominated by larger and more hygroscopic particles. This suggests that compensating effects of hygroscopicity and size determined the temporal stability of f(RH, λ). During sea salt influenced periods, distinct deliquescence transitions were observed. At the end we present a method on how to transfer the dry in-situ measured aerosol scattering coefficients to ambient values for the aerosol measured during summer and fall at this location.ATMOSPHERIC CHEMISTRY AND PHYSICS. 04/2010; 10(8):3875-3890. -
Article: Modelled radiative forcing of the direct aerosol effect with multi-observation evaluation
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ABSTRACT: A high-resolution global aerosol model (Oslo CTM2) driven by meteorological data and allowing a comparison with a variety of aerosol observations is used to simulate radiative forcing (RF) of the direct aerosol effect. The model simulates all main aerosol components, including several secondary components such as nitrate and secondary organic carbon. The model reproduces the main chemical composition and size features observed during large aerosol campaigns. Although the chemical composition compares best with ground-based measurement over land for modelled sulphate, no systematic differences are found for other compounds. The modelled aerosol optical depth (AOD) is compared to remote sensed data from AERONET ground and MODIS and MISR satellite retrievals. To gain confidence in the aerosol modelling, we have tested its ability to reproduce daily variability in the aerosol content, and this is performing well in many regions; however, we also identified some locations where model improvements are needed. The annual mean regional pattern of AOD from the aerosol model is broadly similar to the AERONET and the satellite retrievals (mostly within 10–20%). We notice a significant improvement from MODIS Collection 4 to Collection 5 compared to AERONET data. Satellite derived estimates of aerosol radiative effect over ocean for clear sky conditions differs significantly on regional scales (almost up to a factor two), but also in the global mean. The Oslo CTM2 has an aerosol radiative effect close to the mean of the satellite derived estimates. We derive a radiative forcing (RF) of the direct aerosol effect of −0.35 Wm−2 in our base case. Implementation of a simple approach to consider internal black carbon (BC) mixture results in a total RF of −0.28 Wm−2. Our results highlight the importance of carbonaceous particles, producing stronger individual RF than considered in the recent IPCC estimate; however, net RF is less different. A significant RF from secondary organic aerosols (SOA) is estimated (close to −0.1 Wm−2). The SOA also contributes to a strong domination of secondary aerosol species for the aerosol composition over land. A combination of sensitivity simulations and model evaluation show that the RF is rather robust and unlikely to be much stronger than in our best estimate.Atmospheric Chemistry and Physics. 01/2009; 9:1365-1392. -
Article: Fossil and non-fossil sources of organic carbon (OC) and elemental carbon (EC) in Göteborg, Sweden
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ABSTRACT: Particulate matter was collected at an urban site in Göteborg (Sweden) in February/March 2005 and in June/July 2006. Additional samples were collected at a rural site for the winter period. Total carbon (TC) concentrations were 2.1–3.6 μg m−3, 1.8–1.9 μg m−3, and 2.2–3.0 μg m−3 for urban/winter, rural/winter, and urban/summer conditions, respectively. Elemental carbon (EC), organic carbon (OC), water-insoluble OC (WINSOC), and water-soluble OC (WSOC) were analyzed for 14C in order to distinguish fossil from non-fossil emissions. As wood burning is the single major source of non-fossil EC, its contribution can be quantified directly. For non-fossil OC, the wood-burning fraction was determined independently by levoglucosan and 14C analysis and combined using Latin-hypercube sampling (LHS). For the winter period, the relative contribution of EC from wood burning to the total EC was >3 times higher at the rural site compared to the urban site, whereas the absolute concentrations of EC from wood burning were elevated only moderately at the rural compared to the urban site. Thus, the urban site is substantially more influenced by fossil EC emissions. For summer, biogenic emissions dominated OC concentrations most likely due to secondary organic aerosol (SOA) formation. During both seasons, a more pronounced fossil signal was observed for Göteborg than has previously been reported for Zurich, Switzerland. Analysis of air mass origin using back trajectories suggests that the fossil impact was larger when local sources dominated, whereas long-range transport caused an enhanced non-fossil signal. In comparison to other European locations, concentrations of levoglucosan and other monosaccharide anhydrides were low for the urban and the rural site in the area of Göteborg during winter.Atmospheric Chemistry and Physics. 01/2009; -
Article: Carbonaceous aerosols in Norwegian urban areas
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ABSTRACT: Little is known regarding levels and source strength of carbonaceous aerosols in Scandinavia. In the present study, ambient aerosol (PM10 and PM2.5) concentrations of elemental carbon (EC), organic carbon (OC), water-insoluble organic carbon (WINSOC), and water-soluble organic carbon (WSOC) are reported for a curbside site, an urban background site, and a suburban site in Norway in order to investigate their spatial and seasonal variations. Aerosol filter samples were collected using tandem filter sampling to correct for the positive sampling artefact introduced by volatile and semivolatile OC. Analyses were performed using the thermal optical transmission (TOT) instrument from Sunset Lab Inc., which corrects for charring during analysis. Finally, we estimated the relative contribution of OC from wood burning based on the samples content of levoglucosan. Levels of EC varied by more than one order of magnitude between sites, likely due to the higher impact of vehicular traffic at the curbside and the urban background sites. In winter, the level of particulate organic carbon (OCp) at the suburban site was equal to (for PM10) or even higher (for PM2.5) than the levels observed at the curbside and the urban background sites. This finding was attributed to the impact of residential wood burning at the suburban site in winter, which was confirmed by a high mean concentration of levoglucosan (407 ng m−3). This finding indicates that exposure to primary combustion derived OCp could be equally high in residential areas as in a city center. It is demonstrated that OCp from wood burning (OCwood) accounted for almost all OCp at the suburban site in winter, allowing a new estimate of the ratio TCp/levoglucosan for both PM10 and PM2.5. Particulate carbonaceous material (PCM=Organic matter+Elemental matter) accounted for 46–83% of PM10 at the sites studied, thus being the major fraction.Atmospheric Chemistry and Physics. 01/2009; -
Article: Toward a standardised thermal-optical protocol for measuring atmospheric organic and elemental carbon: the EUSAAR protocol
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ABSTRACT: Thermal-optical analysis is a conventional method for determining the carbonaceous aerosol fraction and for classifying it into organic carbon, OC, and elemental carbon, EC. Unfortunately, the different thermal evolution protocols in use can result in a wide elemental carbon-to-total carbon variation by up to a factor of five. In Europe, there is currently no standard procedure for determining the carbonaceous aerosol fraction which implies that data from different laboratories at various sites are of unknown accuracy and cannot be considered comparable. In the framework of the EU-project EUSAAR (European Supersites for Atmospheric Aerosol Research), a comprehensive study has been carried out to identify the causes of differences in the EC measured using different thermal evolution protocols; thereby the major positive and negative biases affecting thermal-optical analysis have been isolated and minimised to define an optimised protocol suitable for European aerosols. Our approach to improve the accuracy of the discrimination between OC and EC was essentially based on four goals. Firstly, charring corrections rely on faulty assumptions – e.g. pyrolytic carbon is considered to evolve completely before native EC throughout the analysis –, thus we have reduced pyrolysis to a minimum by favoring volatilisation of OC. Secondly, we have minimised the potential negative bias in EC determination due to early evolution of light absorbing carbon species at higher temperatures in the He-mode, including both native EC and combinations of native EC and pyrolytic carbon potentially with different specific cross section values. Thirdly, we have minimised the potential positive bias in EC determination resulting from the incomplete evolution of OC during the He-mode which then evolves during the He/O2-mode, potentially after the split point. Finally, we have minimised the uncertainty due to the position of the OC/EC split point on the FID response profile by introducing multiple desorption steps in the He/O2-mode. Based on different types of carbonaceous PM encountered across Europe, we have defined an optimised thermal evolution protocol, the EUSAAR_2 protocol, as follows: step 1 in He, 200°C for 120 s; step 2 in He 300°C for 150 s; step 3 in He 450°C for 180 s; step 4 in He 650°C for 180 s. For steps 1–4 in He/O2, the conditions are 500°C for 120 s, 550°C for 120 s, 700°C for 70 s, and 850°C for 80 s, respectively.Atmospheric Measurement Techniques Discussions. 01/2009; -
Article: Fossil and non-fossil sources of organic carbon (OC) and elemental carbon (EC) in Göteborg, Sweden
[show abstract] [hide abstract]
ABSTRACT: Particulate matter was collected at an urban site in Göteborg (Sweden) in February/March 2005 and in June/July 2006. Additional samples were collected at a rural site for the winter period. Elemental carbon (EC), organic carbon (OC), water-insoluble OC (WINSOC), and water-soluble OC (WSOC) were analyzed for 14C in order to distinguish fossil from non-fossil emissions. As wood burning is the single major source of non-fossil EC, its contribution can be quantified directly. For non-fossil OC, the wood burning fraction was determined independently by levoglucosan and 14C analysis and combined using Latin-hypercube sampling (LHS). For the winter period, the relative contribution of EC from wood burning to the total EC was >3 times higher at the rural site compared to the urban site, whereas the absolute concentrations of EC from wood burning were comparable at both sites. Thus, the urban site is substantially more influenced by fossil EC emissions. For summer, biogenic emissions dominated OC concentrations most likely due to secondary organic aerosol (SOA) formation. During both seasons, a more pronounced fossil signal was observed for Göteborg than has previously been reported for Zurich, Switzerland. Analysis of air mass origin using back trajectories suggests that the fossil impact was larger when local sources dominated, whereas long-range transport caused an enhanced non-fossil signal. In comparison to other European locations, concentrations of levoglucosan and other monosaccharide anhydrides were low for the urban and the rural site in the area of Göteborg during winter. The comparison of summer and winter results provides insight into the annual cycle of anthropogenic vs. biogenic contributions to the atmospheric aerosol.Atmospheric Chemistry and Physics Discussions. 01/2008; -
Article: Carbonaceous aerosols at urban influenced sites in Norway
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ABSTRACT: Little is known regarding levels and source strength of carbonaceous aerosols in Scandinavia. In the present study, ambient aerosol (PM10 and PM2.5) concentrations of elemental carbon (EC), organic carbon (OC), water-insoluble organic carbon (WINSOC), and water-soluble organic carbon (WSOC) are reported for a curbside site, an urban background site, and a suburban site in Norway in order to investigate their spatial and seasonal variations. Aerosol filter samples were collected using tandem filter sampling to correct for the positive sampling artefact introduced by semi volatile OC. Analyses were performed using the thermal optical transmission (TOT) instrument from Sunset Lab Inc., which corrects for charring during analysis. Finally, we estimated the relative contribution of OC from wood burning based on the samples content of levoglucosan. Levels of EC varied by more than one order of magnitude between sites, likely due to the higher impact of vehicular traffic at the curbside and the urban background sites. In winter, the level of particulate organic carbon (OCp) at the suburban site was equal to (for PM10) or even higher (for PM2.5) than the levels observed at the curbside and the urban background sites. This finding was attributed to the impact of residential wood burning at the suburban site in winter, which was confirmed by a high mean concentration of levoglucosan (407 ng m−3). This finding indicates that exposure to primary combustion derived OCp could be equally high in residential areas as in a city center. It is demonstrated that OCp from wood burning (OCwood) accounted for almost all OCp at the suburban site in winter, allowing a new estimate of the ratio TCp/levoglucosan for both PM10 and PM2.5. Particulate carbonaceous material (PCM = Organic matter + Elemental matter) accounted for 46–83% of PM10 at the sites studied when considering the positive artefact of semi volatile OC, thus being the major contributor to PM.Atmospheric Chemistry and Physics Discussions. 01/2008; -
Article: Radiative forcing of the direct aerosol effect using a multi-observation approach
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ABSTRACT: A high-resolution global aerosol model (Oslo CTM2) driven by meteorological data and allowing a comparison with a variety of aerosol observations is used to simulate radiative forcing (RF) of the direct aerosol effect. The model simulates all main aerosol components, including several secondary components such as nitrate and secondary organic carbon. The model reproduces the main chemical composition and size features observed during large aerosol campaigns. Although the chemical composition compares best with ground-based measurement over land for modelled sulphate, no systematic differences are found for other compounds. The modelled aerosol optical depth (AOD) is compared to remote sensed data from AERONET ground and MODIS and MISR satellite retrievals. To gain confidence in the aerosol modelling, we have tested its ability to reproduce daily variability in the aerosol content, and this is performing well in many regions; however, we also identified some locations where model improvements are needed. The annual mean regional pattern of AOD from the aerosol model is broadly similar to the AERONET and the satellite retrievals (mostly within 10–20%). We notice a significant improvement from MODIS Collection 4 to Collection 5 compared to AERONET data. Satellite derived estimates of aerosol radiative effect over ocean for clear sky conditions differs significantly on regional scales (almost up to a factor two), but also in the global mean. The Oslo CTM2 has an aerosol radiative effect close to the mean of the satellite derived estimates. We derive a radiative forcing (RF) of the direct aerosol effect of −0.35 Wm−2 in our base case. Implementation of a simple approach to consider internal black carbon (BC) mixture results in a total RF of −0.28 Wm−2. Our results highlight the importance of carbonaceous particles, producing stronger individual RF than considered in the recent IPCC estimate; however, net RF is less different. A significant RF from secondary organic aerosols (SOA) is estimated (close to −0.1 Wm−2). The SOA also contributes to a strong domination of secondary aerosol species for the aerosol composition over land. A combination of sensitivity simulations and model evaluation show that the RF is rather robust and unlikely to be much stronger than in our best estimate.Atmospheric Chemistry and Physics Discussions. 01/2008; -
Article: Ambient aerosol concentrations of sugars and sugar-alcohols at four different sites in Norway
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ABSTRACT: Sugars and sugar-alcohols are demonstrated to be important constituents of the ambient aerosol water-soluble organic carbon fraction (WSOC), and to be tracers for primary biological aerosol particles (PBAP). In the present study, levels of four sugars (fructose, glucose, sucrose, trehalose) and three sugar-alcohols (arabitol, inositol, mannitol) in ambient aerosols have been quantified using a novel HPLC/HRMS-TOF (High Performance Liquid Chromatography in combination with High Resolution Mass Spectrometry – Time of Flight) method to assess the contribution of PBAP to PM10 and PM2.5. Samples were collected at four sites in Norway at different times of the year in order to reflect the various contributing sources and the spatial and seasonal variation of the selected compounds. Sugars and sugar-alcohols were present at all sites investigated, underlining the ubiquity of these highly polar organic compounds. The highest concentrations were reported for sucrose, reaching a maximum concentration of 320 ng m−3 in PM10 and 55 ng m−3 in PM2.5. The mean concentration of sucrose was up to 10 times higher than fructose, glucose and trehalose. The mean concentrations of the sugar-alcohols were typically lower, or equal, to that of the monomeric sugars and trehalose. Peak concentrations of arabitol and mannitol did not exceed 30 ng m−3 in PM10, and for PM2.5 all concentrations were below 6 ng m−3. Sugars and sugar-alcohols were associated primarily with coarse aerosols except during wintertime at the suburban site in Elverum, where a shift towards sub micron aerosols was observed. It is proposed that this shift was due to the intensive use of wood burning for residential heating at this site during winter, confirmed by high concurrent concentrations of levoglucosan. Elevated concentrations of sugars in PM2.5 were observed during spring and early summer at the rural background site Birkenes. It is hypothesized that this was due to ruptured pollen.Atmospheric Chemistry and Physics Discussions. 01/2007; -
Article: Elemental and organic carbon in PM<sub>10</sub>: a one year measurement campaign within the European Monitoring and Evaluation Programme EMEP
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ABSTRACT: In the present study, ambient aerosol (PM<sub>10</sub>) concentrations of elemental carbon (EC), organic carbon (OC), and total carbon (TC) are reported for 12 European rural background sites and two urban background sites following a one-year (1 July 2002–1 July 2003) sampling campaign within the European Monitoring and Evaluation Programme, EMEP ( http://www.emep.int/ ). The purpose of the campaign was to assess the feasibility of performing EC and OC monitoring on a regular basis and to obtain an overview of the spatial and seasonal variability on a regional scale in Europe. Analyses were performed using the thermal-optical transmission (TOT) instrument from Sunset Lab Inc., operating according to a NIOSH derived temperature program. The annual mean mass concentration of EC ranged from 0.17±0.19 μg m<sup>−3</sup> (mean ± SD) at Birkenes (Norway) to 1.83±1.32 μg m<sup>−3</sup> at Ispra (Italy). The corresponding range for OC was 1.20±1.29 μg m<sup>−3</sup> at Mace Head (Ireland) to 7.79±6.80 μg m<sup>−3</sup> at Ispra. On average, annual concentrations of EC, OC, and TC were three times higher for rural background sites in Central, Eastern and Southern Europe compared to those situated in the Northern and Western parts of Europe. Wintertime concentrations of EC and OC were higher than those recorded during summer for the majority of the sites. Moderate to high Pearson correlation coefficients (r<sub> p </sub>) (0.50–0.94) were observed for EC versus OC for the sites investigated. The lowest correlation coefficients were noted for the three Scandinavian sites: Aspvreten (SE), Birkenes (NO), and Virolahti (FI), and the Slovakian site Stara Lesna, and are suggested to reflect biogenic sources, wild and prescribed fires. This suggestion is supported by the fact that higher concentrations of OC are observed for summer compared to winter for these sites. For the rural background sites, total carbonaceous material accounted for 30±9% of PM<sub>10</sub>, of which 27±9% could be attributed to organic matter (OM) and 3.4±1.0% to elemental matter (EM). OM was found to be more abundant than SO<sub>4</sub><sup>2−</sup> for sites reporting both parameters.Atmospheric Chemistry and Physics Discussions. 01/2007; -
Article: Regional aerosol optical properties and radiative impact of the extreme smoke event in the European Arctic in spring 2006
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ABSTRACT: In spring 2006 a special meteorological situation occurred in the European Arctic region giving record high levels of air pollution. The synoptic situation resulted in extensive transport of pollution predominantly from agricultural fires in Eastern Europe into the Arctic region and record high air-pollution levels were measured at the Zeppelin observatory at Ny-Ålesund (78°54' N, 11°53' E) in the period from 25 April to 12 May. In the present study we investigate the optical properties of the aerosols from this extreme event and we estimate the radiative forcing of this episode. We examine the aerosol optical properties from the source region and into the European Arctic and explore the evolution of the episode and the changes in the optical properties. A number of sites in Eastern Europe, Northern Scandinavia and Svalbard are included in the study. The observations show that the maximum AOD was from 2–3 May at all sites and varies from 0.52 to 0.87, and the corresponding Ångstrøm exponent was relatively large. Lidar measurements from Minsk, ALOMAR (Arctic Lidar Observatory for Middle Atmosphere Research at Andenes) and Ny-Ålesund show that the aerosol layer was below 3 km at all sites the height is decreasing from the source region and into the Arctic. For the AERONET sites included (Minsk, Toravere, Hornsund) we have further studied the evolution of the aerosol size. The single scattering albedo at Svalbard is provided for two sites; Ny-Ålesund and Hornsund. Importantly the calculated single scattering albedo based on the aerosol chemical composition and size distribution from Ny-Ålesund and the AERONET measurements at Hornsund are consistent. We have found strong agreement between the satellite daily MODIS AOD and the ground-based AOD observations. This agreement is crucial for accurate radiative forcing calculations. We calculate a strong negative radiative forcing for the most polluted days employing the analysed ground based data, MODIS AOD and a multi-stream model for radiative transfer of solar radiation. During this specific pollution event the forcing reached values as low as −35 W m−2 in the region. For comparison, the direct forcing of a corresponding aerosol layer with a typical AOD of 0.05 for the season is around −5 W m−2.Atmospheric Chemistry and Physics. 01/2007; -
Article: Elemental and organic carbon in PM10: a one year measurement campaign within the European Monitoring and Evaluation Programme EMEP
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ABSTRACT: In the present study, ambient aerosol (PM<sub>10</sub>) concentrations of elemental carbon (EC), organic carbon (OC), and total carbon (TC) are reported for 12 European rural background sites and two urban background sites following a one-year (1 July 2002–1 July 2003) sampling campaign within the European Monitoring and Evaluation Programme, EMEP http://www.emep.int/ ). The purpose of the campaign was to assess the feasibility of performing EC and OC monitoring on a regular basis and to obtain an overview of the spatial and seasonal variability on a regional scale in Europe. Analyses were performed using the thermal-optical transmission (TOT) instrument from Sunset Lab Inc., operating according to a NIOSH derived temperature program. The annual mean mass concentration of EC ranged from 0.17±0.19 μg m<sup>−3</sup> (mean ± SD) at Birkenes (Norway) to 1.83±1.32 μg m<sup>−3</sup> at Ispra (Italy). The corresponding range for OC was 1.20±1.29 μg m<sup>−3</sup> at Mace Head (Ireland) to 7.79±6.80 μg m<sup>−3</sup> at Ispra. On average, annual concentrations of EC, OC, and TC were three times higher for rural background sites in Central, Eastern and Southern Europe compared to those situated in the Northern and Western parts of Europe. Wintertime concentrations of EC and OC were higher than those recorded during summer for the majority of the sites. Moderate to high Pearson correlation coefficients ( r <sub> p </sub>) (0.50–0.94) were observed for EC versus OC for the sites investigated. The lowest correlation coefficients were noted for the three Scandinavian sites: Aspvreten (SE), Birkenes (NO), and Virolahti (FI), and the Slovakian site Stara Lesna, and are suggested to reflect biogenic sources, wild and prescribed fires. This suggestion is supported by the fact that higher concentrations of OC are observed for summer compared to winter for these sites. For the rural background sites, total carbonaceous material accounted for 30±9% of PM<sub>10</sub>, of which 27±9% could be attributed to organic matter (OM) and 3.4±1.0% to elemental matter (EM). OM was found to be more abundant than SO<sub>4</sub><sup>2-</sup> for sites reporting both parameters.Atmospheric Chemistry and Physics. 01/2007; -
Article: Arctic smoke ? record high air pollution levels in the European Arctic due to agricultural fires in Eastern Europe in spring 2006
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ABSTRACT: In spring 2006, the European Arctic was abnormally warm, setting new historical temperature records. During this warm period, smoke from agricultural fires in Eastern Europe intruded into the European Arctic and caused the most severe air pollution episodes ever recorded there. This paper confirms that biomass burning (BB) was indeed the source of the observed air pollution, studies the transport of the smoke into the Arctic, and presents an overview of the observations taken during the episode. Fire detections from the MODIS instruments aboard the Aqua and Terra satellites were used to estimate the BB emissions. The FLEXPART particle dispersion model was used to show that the smoke was transported to Spitsbergen and Iceland, which was confirmed by MODIS retrievals of the aerosol optical depth (AOD) and AIRS retrievals of carbon monoxide (CO) total columns. Concentrations of halocarbons, carbon dioxide and CO, as well as levoglucosan and potassium, measured at Zeppelin mountain near Ny Ålesund, were used to further corroborate the BB source of the smoke at Spitsbergen. The ozone (O<sub>3</sub>) and CO concentrations were the highest ever observed at the Zeppelin station, and gaseous elemental mercury was also elevated. A new O<sub>3</sub> record was also set at a station on Iceland. The smoke was strongly absorbing ? black carbon concentrations were the highest ever recorded at Zeppelin ? and strongly perturbed the radiation transmission in the atmosphere: aerosol optical depths were the highest ever measured at Ny Ålesund. We furthermore discuss the aerosol chemical composition, obtained from filter samples, as well as the aerosol size distribution during the smoke event. Photographs show that the snow at a glacier on Spitsbergen became discolored during the episode and, thus, the snow albedo was reduced. Samples of this polluted snow contained strongly elevated levels of potassium, sulphate, nitrate and ammonium ions, thus relating the discoloration to the deposition of the smoke aerosols. This paper shows that, to date, BB has been underestimated as a source of aerosol and air pollution for the Arctic, relative to emissions from fossil fuel combustion. Given its significant impact on air quality over large spatial scales and on radiative processes, the practice of agricultural waste burning should be banned in the future. -
Article: Arctic smoke ? record high air pollution levels in the European Arctic due to agricultural fires in Eastern Europe
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ABSTRACT: In spring 2006, the European Arctic was abnormally warm, setting new historical temperature records. During this warm period, smoke from agricultural fires in Eastern Europe intruded into the European Arctic and caused the most severe air pollution episodes ever recorded there. This paper confirms that biomass burning (BB) was indeed the source of the observed air pollution, studies the transport of the smoke into the Arctic, and presents an overview of the observations taken during the episode. Fire detections from the MODIS instruments aboard the Aqua and Terra satellites were used to estimate the BB emissions. The FLEXPART particle dispersion model was used to show that the smoke was transported to Spitsbergen and Iceland, which was confirmed by MODIS retrievals of the aerosol optical depth (AOD) and AIRS retrievals of carbon monoxide (CO) total columns. Concentrations of halocarbons, carbon dioxide and CO, as well as levoglucosan and potassium, measured at Zeppelin mountain near Ny Ålesund, were used to further corroborate the BB source of the smoke at Spitsbergen. The ozone (O<sub>3</sub>) and CO concentrations were the highest ever observed at the Zeppelin station, and gaseous elemental mercury was also enhanced. A new O<sub>3</sub> record was also set at a station on Iceland. The smoke was strongly absorbing ? black carbon concentrations were the highest ever recorded at Zeppelin ?, and strongly perturbed the radiation transmission in the atmosphere: aerosol optical depths were the highest ever measured at Ny Ålesund. We furthermore discuss the aerosol chemical composition, obtained from filter samples, as well as the aerosol size distribution during the smoke event. Photographs show that the snow at a glacier on Spitsbergen became discolored during the episode and, thus, the snow albedo was reduced. Samples of this polluted snow contained strongly enhanced levels of potassium, sulphate, nitrate and ammonium ions, thus relating the discoloration to the deposition of the smoke aerosols. This paper shows that, to date, BB has been underestimated as a source of aerosol and air pollution for the Arctic, relative to emissions from fossil fuel combustion. Given its significant impact on air quality over large spatial scales and on radiative processes, the practice of agricultural waste burning should be banned in the future. -
Conference Proceeding: Long-range transport of air pollution into the Arctic
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ABSTRACT: This paper presents an overview of air pollution transport into the Arctic. The major transport processes will be highlighted, as well as their seasonal, interannual, and spatial variability. The source regions of Arctic air pollution will be discussed, with a focus on black carbon (BC) sources, as BC can produce significant radiative forcing in the Arctic. It is found that Europe is the main source region for BC in winter, whereas boreal forest fires are the strongest source in summer, especially in years of strong burning. Two case studies of recent extreme Arctic air pollution events will be presented. In summer 2004, boreal forest fires in Alaska and Canada caused pan-Arctic enhancements of black carbon. The BC concentrations measured at Barrow (Alaska), Alert (Canada), Summit (Greenland) and Zeppelin (Spitsbergen) were all episodically elevated, as a result of the long-range transport of the biomass burning emissions. Aerosol optical depth was also episodically elevated at these stations, with an almost continuous elevation over more than a month at Summit. During the second episode in spring 2006, new records were set for all measured air pollutant species at the Zeppelin station (Spitsbergen) as well as for ozone in Iceland. At Zeppelin, BC, AOD, aerosol mass, ozone, carbon monoxide and other compounds all reached new record levels, compared to the long-term monitoring record. The episode was caused by transport of polluted air masses from Eastern Europe deep into the Arctic, a consequence of the unusual warmth in the European Arctic during the episode. While fossil fuel combustion sources certainly contributed to this episode, smoke from agricultural fires in Eastern Europe was the dominant pollution component. We also suggest a new revolatilization mechanism for persistent organic pollutants (POPs) stored in soils and vegetation by fires, as POPs were strongly elevated during both episodes. All this suggests a considerable influence of biomass burning on the pollutant concentrations in the Arctic in spring and summer, even for species that are produced exclusively by humans, such as POPs.2007 AGU Fall Meeting;
Top co-authors
Institutions
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2007–2008
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Norwegian Institute for Air Research
Oslo, Oslo, Norway
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