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Primary sources of PM2.5 organic aerosol in an industrial Mediterranean city, Marseille
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 5. El Haddad I.; Marchand N.; Wortham H.; et al. - Copernicus GmbH, 2011Marseille, the most important port of the Mediterranean Sea, represents a challenging case study for source apportionment exercises, combining an active photochemistry and multiple emission sources, including fugitive emissions from industrial sources and shipping. This paper presents a Chemical Mass Balance (CMB) approach based on organic markers and metals to apportion the primary sources of organic aerosol in Marseille, with a special focus on industrial emissions. Overall, the CMB model accounts for the major primary anthropogenic sources including motor vehicles, biomass burning and the a ...
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Available online: http://dx.doi.org/10.5194/acp-11-2039-2011
I. El Haddad ; N. Marchand ; H. Wortham ; C. Piot ; J.-L. Besombes ; J. Cozic ; C. Chauvel ; A. Armengaud ; D. Robin ; J.-L. Jaffrezo
in Atmospheric Chemistry and Physics (ACP) > Vol. 11. N° 5 [03/11/2011] . - p.2039-2058Marseille, the most important port of the Mediterranean Sea, represents a challenging case study for source apportionment exercises, combining an active photochemistry and multiple emission sources, including fugitive emissions from industrial sources and shipping. This paper presents a Chemical Mass Balance (CMB) approach based on organic markers and metals to apportion the primary sources of organic aerosol in Marseille, with a special focus on industrial emissions. Overall, the CMB model accounts for the major primary anthropogenic sources including motor vehicles, biomass burning and the aggregate emissions from three industrial processes (heavy fuel oil combustion/shipping, coke production and steel manufacturing) as well as some primary biogenic emissions. This source apportionment exercise is well corroborated by 14C measurements. Primary OC estimated by the CMB accounts on average for 22% of total OC and is dominated by the vehicular emissions that contribute on average for 17% of OC mass concentration (vehicular PM contributes for 17% of PM2.5). Even though industrial emissions contribute only 2.3% of the total OC (7% of PM2.5), they are associated with ultrafine particles (Dp<80 nm) and high concentrations of Polycyclic Aromatic Hydrocarbons (PAH) and heavy metals such as Pb, Ni and V. On one hand, given that industrial emissions governed key primary markers, their omission would lead to substantial uncertainties in the CMB analysis performed in areas heavily impacted by such sources, hindering accurate estimation of non-industrial primary sources and secondary sources. On the other hand, being associated with bursts of submicron particles and carcinogenic and mutagenic components such as PAH, these emissions are most likely related with acute ill-health outcomes and should be regulated despite their small contributions to OC. Another important result is the fact that 78% of OC mass cannot be attributed to the major primary sources and, thus, remains un-apportioned. We have consequently critically investigated the uncertainties underlying our CMB apportionments. While we have provided some evidence for photochemical decay of hopanes, this decay does not appear to significantly alter the CMB estimates of the total primary OC. Sampling artifacts and unaccounted primary sources also appear to marginally influence the amount of un-apportioned OC. Therefore, this significant amount of un-apportioned OC is mostly attributed to secondary organic carbon that appears to be the major component of OC during the whole period of study.
Language(s): English
Format: Digital (Free)Tags: Aerosols ; Environment and landscape ; Urban zone ; Air pollution ; France
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Three-year ground based measurements of aerosol optical depth over the Eastern Mediterranean: the urban environment of Athens
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 5. Gerasopoulos E.; Amiridis V.; Kazadzis S.; et al. - Copernicus GmbH, 2011Three years (2006–2008) of ground-based observations of the Aerosol Optical Depth (AOD) in the urban environment of Athens, in the Eastern Mediterranean, are analysed in this work. Measurements were acquired with a Multi-Filter Rotating Shadowband Radiometer at five wavelengths. The daily average AOD at 500 nm is 0.23, and the mean Ångström coefficient calculated between 415 and 867 nm is 1.41. The annual variability of AOD has a spring maximum dominated by coarse dust particles from the Sahara (AOD 0.34–0.42), while the diurnal pattern is typical for urban sites, with AOD steadily increasing ...
[article]Three-year ground based measurements of aerosol optical depth over the Eastern Mediterranean: the urban environment of Athens
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Available online: http://dx.doi.org/10.5194/acp-11-2145-2011
E. Gerasopoulos ; V. Amiridis ; S. Kazadzis ; P. Kokkalis ; K. Eleftheratos ; M.O. Andreae ; T.W. Andreae ; H. El-Askary ; Christos S. Zerefos
in Atmospheric Chemistry and Physics (ACP) > Vol. 11. N° 5 [03/11/2011] . - p.2145-2159Three years (2006–2008) of ground-based observations of the Aerosol Optical Depth (AOD) in the urban environment of Athens, in the Eastern Mediterranean, are analysed in this work. Measurements were acquired with a Multi-Filter Rotating Shadowband Radiometer at five wavelengths. The daily average AOD at 500 nm is 0.23, and the mean Ångström coefficient calculated between 415 and 867 nm is 1.41. The annual variability of AOD has a spring maximum dominated by coarse dust particles from the Sahara (AOD 0.34–0.42), while the diurnal pattern is typical for urban sites, with AOD steadily increasing throughout the day. The greatest contribution to the annually averaged AOD, accounting for almost 40%, comes from regional and local sources (namely the Istanbul metropolitan area, the extended areas of biomass burning around the north coast of the Black Sea, power plants spread throughout the Balkans and the industrial area in the Po valley, with average daily AOD in the range of 0.25–0.35). An additional important contribution (23%) is dust from Africa, whereas the rest of Europe contributes another 22%. The geographical distribution of the above sources in conjunction with the prevailing synoptic situation and contribution of local sources, lead to mixed types of aerosols over Athens, with highly variable contribution of fine and coarse particles to AOD in the range 10%–90%. This is the first long-term, ground based data set available for Athens, and it has also been used for the validation of satellite derived AOD by MODIS, showing good agreement on an annual basis, but with an overestimation of satellite AODs in the warm period.
Language(s): English
Format: Digital (Free)Tags: Aerosols ; Environment and landscape ; Urban zone ; Air pollution ; Greece
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Boundary layer dynamics over London, UK, as observed using Doppler lidar during REPARTEE-II
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 5. Barlow J.F.; Dunbar T.M.; Nemitz E.G.; et al. - Copernicus GmbH, 2011Urban boundary layers (UBLs) can be highly complex due to the heterogeneous roughness and heating of the surface, particularly at night. Due to a general lack of observations, it is not clear whether canonical models of boundary layer mixing are appropriate in modelling air quality in urban areas. This paper reports Doppler lidar observations of turbulence profiles in the centre of London, UK, as part of the second REPARTEE campaign in autumn 2007. Lidar-measured standard deviation of vertical velocity averaged over 30 min intervals generally compared well with in situ sonic anemometer measure ...
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Available online: http://dx.doi.org/10.5194/acp-11-2111-2011
J.F. Barlow ; T.M. Dunbar ; E.G. Nemitz ; C.R. Wood ; M.W. Gallagher ; F. Davies ; E. O'Connor ; R.M. Harrison
in Atmospheric Chemistry and Physics (ACP) > Vol. 11. N° 5 [03/11/2011] . - p.2111-2125Urban boundary layers (UBLs) can be highly complex due to the heterogeneous roughness and heating of the surface, particularly at night. Due to a general lack of observations, it is not clear whether canonical models of boundary layer mixing are appropriate in modelling air quality in urban areas. This paper reports Doppler lidar observations of turbulence profiles in the centre of London, UK, as part of the second REPARTEE campaign in autumn 2007. Lidar-measured standard deviation of vertical velocity averaged over 30 min intervals generally compared well with in situ sonic anemometer measurements at 190 m on the BT telecommunications Tower. During calm, nocturnal periods, the lidar underestimated turbulent mixing due mainly to limited sampling rate. Mixing height derived from the turbulence, and aerosol layer height from the backscatter profiles, showed similar diurnal cycles ranging from c. 300 to 800 m, increasing to c. 200 to 850 m under clear skies. The aerosol layer height was sometimes significantly different to the mixing height, particularly at night under clear skies. For convective and neutral cases, the scaled turbulence profiles resembled canonical results; this was less clear for the stable case. Lidar observations clearly showed enhanced mixing beneath stratocumulus clouds reaching down on occasion to approximately half daytime boundary layer depth. On one occasion the nocturnal turbulent structure was consistent with a nocturnal jet, suggesting a stable layer. Given the general agreement between observations and canonical turbulence profiles, mixing timescales were calculated for passive scalars released at street level to reach the BT Tower using existing models of turbulent mixing. It was estimated to take c. 10 min to diffuse up to 190 m, rising to between 20 and 50 min at night, depending on stability. Determination of mixing timescales is important when comparing to physico-chemical processes acting on pollutant species measured simultaneously at both the ground and at the BT Tower during the campaign. From the 3 week autumnal data-set there is evidence for occasional stable layers in central London, effectively decoupling surface emissions from air aloft.
Language(s): English
Format: Digital (Free)Tags: Aerosols ; Observations ; Doppler radar ; United Kingdom of Great Britain and Northern Ireland
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Charge induced stability of water droplets in subsaturated environment
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 5. Nielsen J.K.; Maus C.; Rzesanke D.; et al. - Copernicus GmbH, 2011Atmospheric liquid and solid water particles are stabilized if they are coated with either negative or positive electric charge. The surface charge causes an increase of the partial pressure of water vapour close to the surface of each particle, effectively allowing the particles to remain in their condensed phase even if the environmental relative humidity drops below unity. The theory, briefly presented in this paper, predicts a zero parameter relation between surface charge density and water vapour pressure. This relation was tested in a series of Electrodynamic Balance experiments. The mea ...
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Available online: http://dx.doi.org/10.5194/acp-11-2031-2011
in Atmospheric Chemistry and Physics (ACP) > Vol. 11. N° 5 [03/11/2011] . - p.2031-2037Atmospheric liquid and solid water particles are stabilized if they are coated with either negative or positive electric charge. The surface charge causes an increase of the partial pressure of water vapour close to the surface of each particle, effectively allowing the particles to remain in their condensed phase even if the environmental relative humidity drops below unity. The theory, briefly presented in this paper, predicts a zero parameter relation between surface charge density and water vapour pressure. This relation was tested in a series of Electrodynamic Balance experiments. The measurements were performed by stabilizing charged droplets of pure water near an ice-surface. We observed a divergence in radius as the temperature approached the freezing point from below. We find that the measurements confirm the theory within the experimental uncertainty. In some cases this generally overlooked effect may have impact on cloud processes and on results produced by Electrodynamic Balance experiments.
Language(s): English
Format: Digital (Free)Tags: Water ; Environment and landscape ; Air pollution
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Corrigendum to "Controls of carbon dioxide concentrations and fluxes above central London" published in Atmos. Chem. Phys., 11, 1913–1928, 2011
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 5. Helfter C.; Famulari D.; Phillips G.J.; et al. - Copernicus GmbH, 2011
[article]Corrigendum to "Controls of carbon dioxide concentrations and fluxes above central London" published in Atmos. Chem. Phys., 11, 1913–1928, 2011
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Available online: http://dx.doi.org/10.5194/acp-11-2081-2011
C. Helfter ; D. Famulari ; G.J. Phillips ; J.F. Barlow ; C.R. Wood ; C.S.B. Grimmond ; E. Nemitz
in Atmospheric Chemistry and Physics (ACP) > Vol. 11. N° 5 [03/11/2011] . - p.2081Language(s): English
Format: Digital (Free)Tags: Carbon dioxide (CO2) ; Environment and landscape ; Air pollution ; United Kingdom of Great Britain and Northern Ireland
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Dependence of aerosol-precipitation interactions on humidity in a multiple-cloud system
This study examines the dependence of aerosol-precipitation interactions on environmental humidity in a mesoscale cloud ensemble (MCE) which is composed of convective and stratiform clouds. The author found that increases in aerosol concentration enhance evaporative cooling, which raises not only the intensity of vorticity and entrainment but also that of downdrafts and low-level convergence. The increase in vorticity tends to suppress precipitation. The increase in low-level convergence tends to enhance precipitation by generating more secondary clouds in a muptiple-cloud system simulated her ...
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New cloud chamber experiments on the heterogeneous ice nucleation ability of oxalic acid in the immersion mode
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 5. Wagner R.; Möhler O.; Saathoff H.; et al. - Copernicus GmbH, 2011The heterogeneous ice nucleation ability of oxalic acid in the immersion mode has been investigated by controlled expansion cooling runs with airborne, ternary solution droplets composed of, (i), sodium chloride, oxalic acid, and water (NaCl/OA/H2O) and, (ii), sulphuric acid, oxalic acid, and water (H2SO4/OA/H2O). Polydisperse aerosol populations with median diameters ranging from 0.5–0.7 μm and varying solute concentrations were prepared. The expansion experiments were conducted in the AIDA aerosol and cloud chamber of the Karlsruhe Institute of Technology at initial temperatures of 244 and 2 ...
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Characteristics, sources, and transport of aerosols measured in spring 2008 during the aerosol, radiation, and cloud processes affecting Arctic Climate (ARCPAC) Project
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Brock C.A.; Cozic J.; Bahreini R.; et al. - Copernicus GmbH, 2011We present an overview of the background, scientific goals, and execution of the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC) project of April 2008. We then summarize airborne measurements, made in the troposphere of the Alaskan Arctic, of aerosol particle size distributions, composition, and optical properties and discuss the sources and transport of the aerosols. The aerosol data were grouped into four categories based on gas-phase composition. First, the background troposphere contained a relatively diffuse, sulfate-rich aerosol extending from the top of the sea ...
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HFC-152a and HFC-134a emission estimates and characterization of CFCs, CFC replacements, and other halogenated solvents measured during the 2008 ARCTAS campaign (CARB phase) over the South Coast Air Basin of California
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Barletta B.; Nissenson P.; Meinardi S.; et al. - Copernicus GmbH, 2011This work presents results from the NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) study. Whole air samples were obtained on board research flights that flew over California during June 2008 and analyzed for selected volatile organic compounds, including several halogenated species. Samples collected over the South Coast Air Basin of California (SoCAB), which includes much of Los Angeles (LA) County, were compared with samples from inflow air masses over the Pacific Ocean. The levels of many halocarbon species were enhanced significantly over t ...
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Impact of deep convection and dehydration on bromine loading in the upper troposphere and lower stratosphere
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Aschmann J.; Sinnhuber B.-M.; Chipperfield M.P.; et al. - Copernicus GmbH, 2011Stratospheric bromine loading due to very short-lived substances is investigated with a three-dimensional chemical transport model over a period of 21 years using meteorological input data from the European Centre for Medium-Range Weather Forecasts ERA-Interim reanalysis from 1989 to the end of 2009. Within this framework we analyze the impact of dehydration and deep convection on the amount of stratospheric bromine using an idealized and a detailed full chemistry approach. We model the two most important brominated short-lived substances, bromoform (CHBr3) and dibromomethane (CH2Br2), assumin ...
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Investigations of aerosol impacts on hurricanes: virtual seeding flights
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Carrio G.G.; Cotton William R. - Copernicus GmbH, 2011This paper examines the feasibility of mitigating the intensity of hurricanes by enhancing the CCN concentrations in the outer rainband region. Increasing CCN concentrations would cause a reduced collision and coalescence, resulting in more supercooled liquid water to be transported aloft which then freezes and enhances convection via enhanced latent heat of freezing. The intensified convection would condense more water ultimately enhancing precipitation in the outer rainbands. Enhanced evaporative cooling from the increased precipitation in the outer rainbands would produce stronger and more ...
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Size and time-resolved roadside enrichment of atmospheric particulate pollutants
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Amato F.; Viana M.; Richard A.; et al. - Copernicus GmbH, 2011Size and time-resolved roadside enrichments of atmospheric particulate pollutants in PM10 were detected and quantified in a Mediterranean urban environment (Barcelona, Spain). Simultaneous data from one urban background (UB), one traffic (T) and one heavy traffic (HT) location were analysed, and roadside PM10 enrichments (RE) in a number of elements arising from vehicular emissions were calculated. Tracers of primary traffic emissions (EC, Fe, Ba, Cu, Sb, Cr, Sn) showed the largest REs (>70%). Other traffic tracers (Zr, Cd) showed lower but still consistent REs (25–40%), similar to those obtai ...
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Distribution and air-sea exchange of mercury (Hg) in the Yellow Sea
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Ci Z.J.; Zhang X.S.; Wang Z.W.; et al. - Copernicus GmbH, 2011The Yellow Sea, surrounded by East China and the Korea Peninsula, is a potentially important receptor for anthropogenic mercury (Hg) emissions from East Asia. However, there is little documentation about the distribution and cycle of Hg in this marine system. During the cruise covering the Yellow Sea in July 2010, gaseous elemental mercury (GEM or Hg(0)) in the atmosphere, total Hg (THg), reactive Hg (RHg) and dissolved gaseous mercury (DGM, largely Hg(0)) in the waters were measured aboard the R/V Kexue III. The mean (±SD) concentration of GEM over the entire cruise was 2.61 ± 0.50 ng m−3 (ra ...
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Chemical composition and mixing-state of ice residuals sampled within mixed phase clouds
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Ebert M.; Worringen A.; Benker N.; et al. - Copernicus GmbH, 2011During an intensive campaign at the high alpine research station Jungfraujoch, Switzerland, in February/March 2006 ice particle residuals within mixed-phase clouds were sampled using the Ice-counterflow virtual impactor (Ice-CVI). Size, morphology, chemical composition, mineralogy and mixing state of the ice residual and the interstitial (i.e., non-activated) aerosol particles were analyzed by scanning and transmission electron microscopy. Ice nuclei (IN) were identified from the significant enrichment of particle groups in the ice residual (IR) samples relative to the interstitial aerosol. In ...
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Sources of carbonaceous aerosol in the Amazon basin
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Gilardoni S.; Vignati E.; Marmer E.; et al. - Copernicus GmbH, 2011The quantification of sources of carbonaceous aerosol is important to understand their atmospheric concentrations and regulating processes and to study possible effects on climate and air quality, in addition to develop mitigation strategies.
In the framework of the European Integrated Project on Aerosol Cloud Climate Interactions (EUCAARI) fine (Dp < 2.5 μm) and coarse (2.5 μm < Dp <10 μm) aerosol particles were sampled from February to June (wet season) and from August to September (dry season) 2008 in the central Amazon basin. The mass of fine particles averaged 2.4 μg m−3 duri ...
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