scholarly journals Seasonal variation of PM<sub>10</sub> main constituents in two valleys of the French Alps. I: EC/OC fractions

2007 ◽  
Vol 7 (3) ◽  
pp. 661-675 ◽  
Author(s):  
G. Aymoz ◽  
J. L. Jaffrezo ◽  
D. Chapuis ◽  
J. Cozic ◽  
W. Maenhaut
Keyword(s):  
Organic Carbon ◽  
Ratio Method ◽  
French Alps ◽  
Residential Heating ◽  
Secondary Organic Carbon ◽  
Urban Sites ◽  
Pm10 Mass ◽  
Daily Pm10 ◽  
Very High ◽  
High Range

Abstract. Daily PM10 samples were collected at two urban sites within two valleys in the French Alps (Chamonix and St Jean de Maurienne) during a period of two and a half years. The carbonaceous species EC (elemental carbon) and OC (organic carbon) were analysed to investigate the possible sources of EC and OC, and their seasonal variations. Mean OC concentrations are in the very high range of concentrations measured for other European sites, and represent at least one third of the PM10 mass on each site. On the basis of the comparison between EC and OC concentrations with several tracers, we were able to show that their main sources are local primary combustion sources. Biomass burning emissions (residential heating) have a significant impact on OC concentrations while heavy duty traffic emissions have an impact only on EC concentrations. Finally, we estimated the contribution of SOA (secondary organic carbon) to OC, using the EC-to-OC primary ratio method (Castro et al., 1999) and demonstrated that the calculation of SOA mass with this method is highly uncertain, if the hypothesis of a constant primary EC-to-OC ratio is not very closely examined.

scholarly journals Seasonal variation of PM<sub>10</sub> main constituents in two valleys of the French Alps. I: EC/OC fractions

2006 ◽  
Vol 6 (4) ◽  
pp. 6211-6254 ◽  
Author(s):  
G. Aymoz ◽  
J.-L. Jaffrezo ◽  
D. Chapuis ◽  
J. Cozic ◽  
W. Maenhaut
Keyword(s):  
Organic Carbon ◽  
Ratio Method ◽  
French Alps ◽  
Residential Heating ◽  
Secondary Organic Carbon ◽  
Urban Sites ◽  
Pm10 Mass ◽  
Daily Pm10 ◽  
Very High ◽  
High Range

Abstract. Daily PM10 samples were collected at two urban sites within two valleys in the French Alps (Chamonix and St Jean de Maurienne) during a period of two and a half years. The carbonaceous species EC (elemental carbon) and OC (organic carbon) were analysed to investigate the possible sources of EC and OC, and their seasonal variations. Mean OC concentrations are in the very high range of concentrations measured for other European sites, and represent at least one third of the PM10 mass on each site. On the basis of the comparison between EC and OC concentrations with several tracers, we were able to show that their main sources are local primary combustion sources. Biomass burning emissions (residential heating) have a significant impact on OC concentrations while heavy duty traffic emissions have an impact only on EC concentrations. Finally, we estimated the contribution of SOA (secondary organic carbon) to OC, using the EC-to-OC primary ratio method (Castro et al., 1999) and demonstrated that the calculation of SOA mass with this method is highly uncertain, if the hypothesis of a constant primary EC-to-OC ratio is not very closely examined.

Short-term secondary organic carbon estimations with a modified OC/EC primary ratio method at a suburban site in Madrid (Spain)

2011 ◽  
Vol 45 (15) ◽  
pp. 2496-2506 ◽  
Author(s):  
Javier Plaza ◽  
Begoña Artíñano ◽  
Pedro Salvador ◽  
Francisco J. Gómez-Moreno ◽  
Manuel Pujadas ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Ratio Method ◽  
Short Term ◽  
Secondary Organic Carbon ◽  
Suburban Site

Secondary Organic Carbon Estimations with Hourly Monitoring Data and the OC/EC Primary Ratio Method

2013 ◽  
Vol 295-298 ◽  
pp. 849-853
Author(s):  
Mei Fang Lu ◽  
Mei Chuan Huang ◽  
Chiau Yi Wen ◽  
Yi Hui Wu ◽  
Jim Jui Min Lin
Keyword(s):  
Organic Carbon ◽  
Pollution Source ◽  
Photochemical Reactions ◽  
Monitoring Data ◽  
Ratio Method ◽  
High Temporal Resolution ◽  
Data Set ◽  
Daily Data ◽  
Hourly Data ◽  
Secondary Organic Carbon

This study examined the hourly monitoring data from 2006 to 2009 collected by the Aerosol Supersite of the Environmental Protection Administration of Taiwan. The OC/EC primary ratio method has been applied to estimate the content of secondary organic carbon (SOC). Results of this study indicated that the monthly concentrations of PM2.5, OC, and EC all remained low in summer but went up in winter. Possible factors were climate-related and influences from continental high pressure systems. The content (24–36%) of SOC in summer was significantly higher than in other seasons, indicating that a great formation of organic carbon in summer. When considering the hourly trend, apparent peaks can be consistently observed in the morning, which may be due to an increase of mobile pollution source and photochemical reactions. (OC/EC)min ratio values were calculated based on both hourly and daily concentrations of OC and EC, then annual values (2006~2009) were 0.20~1.11 and 0.68~2.72 for hourly and daily data base respectively. Content of SOC in PM2.5 and OC were estimated to be 16~23 % and 75~93 % based on (OC/EC)min ratio from hourly data set, and were 11~18 % and 42~77 % based on (OC/EC)min ratio from daily data set. Results from this study, as well as those from other studies, demonstrated that the OC/EC ratio is dependent upon the sampling method as well as the method of analysis. Furthermore, the daily OC/EC ratio may change, and significant variations may be found even within 24 hours. Taken together, when conducting estimation of SOC, it is important to eliminate the consideration on background concentrations but to take a good advantage of the high temporal resolution of hourly monitoring data in order to estimate SOC using a corrective approach.

scholarly journals Comparison of Measurement-Based Methodologies to Apportion Secondary Organic Carbon (SOC) in PM2.5: A Review of Recent Studies

Atmosphere ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 452 ◽  
Author(s):  
Deepchandra Srivastava ◽  
Olivier Favez ◽  
Emilie Perraudin ◽  
Eric Villenave ◽  
Alexandre Albinet
Keyword(s):  
Organic Carbon ◽  
Current Knowledge ◽  
Airborne Particulate Matter ◽  
Global Scale ◽  
Tracer Method ◽  
Research Papers ◽  
Science Community ◽  
Secondary Organic Carbon ◽  
Predictive Assessments ◽  
Urban Sites

Secondary organic aerosol (SOA) is known to account for a major fraction of airborne particulate matter, with significant impacts on air quality and climate at the global scale. Despite the substantial amount of research studies achieved during these last decades, the source apportionment of the SOA fraction remains difficult due to the complexity of the physicochemical processes involved. The selection and use of appropriate approaches are a major challenge for the atmospheric science community. Several methodologies are nowadays available to perform quantitative and/or predictive assessments of the SOA amount and composition. This review summarizes the current knowledge on the most commonly used approaches to evaluate secondary organic carbon (SOC) contents: elemental carbon (EC) tracer method, chemical mass balance (CMB), SOA tracer method, radiocarbon (14C) measurement and positive matrix factorization (PMF). The principles, limitations, challenges and good practices of each of these methodologies are discussed in the present article. Based on a comprehensive—although not exhaustive—review of research papers published during the last decade (2006–2016), SOC estimates obtained using these methodologies are also summarized for different regions across the world. Conclusions of some studies which are directly comparing the performances of different methodologies are then specifically discussed. An overall picture of SOC contributions and concentrations obtained worldwide for urban sites under similar conditions (i.e., geographical and seasonal ones) is also proposed here. Finally, further needs to improve SOC apportionment methodologies are also identified and discussed.

scholarly journals Soil Water Characteristics of Gleysols in the Bamenda (Cameroon) Wetlands and Implications for Agricultural Management Strategies

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Alice Mufur Magha ◽  
Primus Azinwi Tamfuh ◽  
Lionelle Estelle Mamdem ◽  
Marie Christy Shey Yefon ◽  
Bertrand Kenzong ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Water ◽  
Total Variance ◽  
Organic Carbon Content ◽  
Available Water ◽  
High Soil ◽  
Local Soil ◽  
Very High

Water budgeting in agriculture requires local soil moisture information as crops depend mainly on moisture available at root level. The present paper aims to evaluate the soil moisture characteristics of Gleysols in the Bamenda (Cameroon) wetlands and to evaluate the link between soil moisture content and selected soil characteristics affecting crop production. The work was conducted in the field and laboratory, and data were analyzed by simple descriptive statistics. The main results showed that the soils had a silty clayey to clayey texture, high bulk density, high soil organic carbon content, and high soil organic carbon stocks. The big difference between moisture contents at wilting point and at field capacity testified to very high plant-available water content. Also, the soils displayed very high contents of readily available water and water storage contents. The soil moisture characteristics give sigmoid curves and enabled noting that the Gleysols attain their full water saturation at a range of 57.68 to 91.70% of dry soil. Clay and SOC contents show a significant positive correlation with most of the soil moisture characteristics, indicating that these soil properties are important for soil water retention. Particle density, coarse fragments, and sand contents correlated negatively with the soil moisture characteristics, suggesting that they decrease soil water-holding capacity. The principal component analysis (PCA) enabled reducing 17 variables described to only three principal components (PCs) explaining 73.73% of the total variance; the first PC alone expressed 45.12% of the total variance, associating clay, SOC, and six soil moisture characteristics, thus portraying a deep correlation between these eight variables. Construction of contoured ditches, deep tillage, and raised ridges management techniques during the rainy season while channeling water from nearby water bodies into the farmland, opportunity cropping, and usage of water cans and other irrigation strategies are used during the dry season to combat water constraints.

scholarly journals CHARACTERISTICS OF RICE SOILS FROM THE TIDAL FLAT AREAS OF MUSI BANYUASIN, SOUTH SUMATRA

2016 ◽  
Vol 2 (1) ◽  
pp. 10 ◽  
Author(s):  
B.H. Prasetyo ◽  
S. Suping ◽  
Subagyo H. ◽  
Mujiono Mujiono ◽  
H. Suhardjo
Keyword(s):  
Organic Carbon ◽  
Tidal Flat ◽  
Amorphous Materials ◽  
Mineral Soil ◽  
Soil Samples ◽  
Moisture Regime ◽  
Organic Carbon Content ◽  
Rice Soils ◽  
Specific Chemical ◽  
Very High

Tidal flats in the Musi Banyuasin region that cover more than 200,000 ha are the largest area for agricultural development in South Sumatra Province. Only about a half of this has been used for tidal swamp rice fields, therefore, the other half needs to be developed. To obtain a better understanding of their properties for appropriate soil management, soil characteristics of the area need to be studied. To characterize the soil, thirty-four soil samples from seven soil profiles were analyzed for their chemical and mineralogical composition at the laboratories of the Center for Soil and Agroclimate Research and Development. The results indicate that soils from the tidal flat areas have an aquic soil moisture regime, the upper parts of the soils are mostly ripe, and most of the pedons show the presence of sulfidic materials below 65 cm of the mineral soil surface. The soils are classified as Sulfic Endoaquept (P1, P2), Histic Sulfaquent (P3), Typic Sulfaquept (P4), Fluvaquentic Endoaquept (P5), and Sulfic Hydraquent (P6, P7). Mineral composition of the sand fraction is dominated by quartz, while the clay minerals consist of predominantly kaolinite, mixed with small amount of smectite, illite, quartz, and crystoballite. Organic carbon content is high to very high, potential phosphate content of most pedons ranges from very low to medium, while potential potassium content varies from very low to medium in the upper layers and medium to very high in the bottom layers. Phosphate retention of topsoil sample varies from 56 to 97%, and is positively correlated (r2 = 0.73) with aluminum from amorphous materials. Exchangeable cations are dominated by Mg cation, and in all pedons cation exchange capacity values are medium to very high, and seem to be influenced by organic carbon. Specific chemical properties, particularly soil pH and content of exchangeable aluminum exhibit a significant change about 1-2 months after soil samples were taken from the field. Theoretically, interaction between good water management and fertilizer application are among the choices of management to make these soils productive.

Solubilité de l'or dans les eaux interstitielles de la latérite coiffant le gîte aurifère de Misséni, au Mali

1993 ◽  
Vol 30 (8) ◽  
pp. 1553-1565 ◽  
Author(s):  
Frédéric Séa ◽  
Marc G. Tanguay ◽  
Pierre Trudel ◽  
Mario Bergeron
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Organic Carbon ◽  
Humic Acids ◽  
Chloride Ion ◽  
High Solubility ◽  
Gold Solubility ◽  
Mn Oxides ◽  
Very High ◽  
Interstitial Waters

Twenty samples of interstitial waters and pressed saprolite were collected within undisturbed saprolite blocks to determine the actual gold transporting mode in the auriferous laterites of Misséni, Mali. The results of the analyses indicate a very high solubility of gold in the interstitial waters of the Misséni laterites (from <2 to 16.7 ppb Au; Eh, 0.356–0.419 V; pH, 6.7–7.7). The calculated theoretical concentrations of auric chloride ion, [Formula: see text], (0.3 × 10−14 – 32.7 × 10−4 ppm) and thiosulphate ion, [Formula: see text], (2.5 × 10−212 – 6.7 × 10−180 ppm), which are generally inferred to be the ions transporting the gold in a supergene environment, are insignificant in the interstitial waters of the Misséni saprolite. Given the absence of significant concentrations of chloride or thiosulphate ions as measured in the interstitial waters of Misséni (Cl−, 1.5 × 10−4 – 1.2 × 10−2 mol L−1; [Formula: see text], 1.1 × 10−111 – 4.2 × 10−95 mol L−1), the gold monohydroxide, AuOH(H2O)0, could be responsible for the gold mobilization in the studied saprolite. However, its transport could be limited by the conspicuous (Fe, Mn) oxides in the Misséni saprolite, which can act as adsorbents. The calculated concentrtion of humic acid (0.004–0.03%), which can solubilize the gold contained in the analyzed interstitial waters, is 2 to 4 times lower than that of the measured organic matter in the samples of pressed saprolite (from <0.016 to 0.07% in organic carbon). These latter results could indicate that a part of the gold solubility in the Misséni superficial saprolite is linked to the humic acids. [Journal Translation]

Regional study of orogenic ultramafics of the Seve Nappe Complex, Scandinavian Caledonides - preliminary results from northern and central Jämtland, Sweden

2021 ◽  
Author(s):  
Daniel Buczko ◽  
Magdalena Matusiak-Małek ◽  
Jarosław Majka ◽  
Iwona Klonowska ◽  
Grzegorz Ziemniak
Keyword(s):  
Preliminary Data ◽  
Regional Study ◽  
Scandinavian Caledonides ◽  
Nappe Complex ◽  
Science Centre ◽  
Seve Nappe Complex ◽  
End Members ◽  
Very High ◽  
Different Levels ◽  
High Range

&lt;p&gt;The Scandinavian Caledonides comprise numerous ultramafic bodies emplaced within metamorphic nappe complexes. A hypothetical suture between the most distal crustal units representing Baltican margin (Seve Nappe Complex, SNC) with the oceanic Iapetian terranes (K&amp;#246;li Nappe Complex) is abundant in such occurrences. Here we present preliminary data on garnet/spinel peridotites/pyroxenites from SNC in central and northern parts of Swedish J&amp;#228;mtland county. The presented results are a part of a project involving regional study focused on orogenic peridotites (mostly spinel-bearing) of Seve and K&amp;#246;li nappe complexes.&amp;#160;&lt;/p&gt;&lt;p&gt;The ultramafic bodies in the study area range from a meters to kilometer scale and comprise: 1) garnet peridotites, 2) spinel peridotites, 3) spinel pyroxenites and 4) garnet pyroxenites. Individual outcrops often record different levels of serpentinisation.&amp;#160;&lt;/p&gt;&lt;p&gt;The Grt-peridotites are usually harzburgites (sparsely dunites/lherzolites) with an assemblage of Ol+Opx+Cpx+Amph+Grt+Spl.&amp;#160; Minerals within the Grt-peridotites are characterised by Ol Fo=~90-91 and Mg# in pyroxenes 90-92 and 92-96 (enstatite and diopside/Cr-diopside, respectively). Garnet is pyrope with end-members Prp=60-69%, Usp=0-4% and Cr#=0.5-4. Amphibole (pargasite; Mg#=88-92) typically occurs as patches or rims around Grt and often host significant amounts of Spl. The spinel has an intermediate composition between hercynite-spinel and magnesiochromite-chromite (Cr#=41-55, Mg#=40-57).&amp;#160;&lt;/p&gt;&lt;p&gt;The spinel peridotites are formed of Ol+Opx+Amph+Chl+Spl and classify mostly as harzburgites/dunites. Olivine and Opx (enstatite, rarely Cr-enstatite; often as porphyrocrysts) show a high range of Fo/Mg# values (90-95 and 90-94, respectively). Amphibole (tremolite; Mg#=91-96) is usually evenly distributed within the rock, while Chl is often associated with grain boundaries. Spinel has a chromite composition (Cr#=82-100, Mg#=5-10). Within single large (~0.5mm) spinel grains, cores with higher Mg# (~23) and lower Cr# (~82) can be observed.&lt;/p&gt;&lt;p&gt;The garnet pyroxenites are websterites characterised by lower Mg# (88-90) in enstatite, presence of Al-diopside and lower Cr# (&lt;0.5) in pyrope than in peridotites. The Spl-pyroxenites are orthopyroxenites with Mg# in enstatite (86-88) lower than in peridotitic orthopyroxene.&lt;/p&gt;&lt;p&gt;The presented preliminary data suggest that lithologies formed under different pressures (i.e. Grt and Spl facies) and must have recorded different evolution paths. Garnet ultramafics mineralogy resembles typical &amp;#8220;mantle&amp;#8221; assemblage with Prg suggesting possible metamorphic input also for other consisting phases (similarly to M2 paragenesis described in [1]). While the Grt ultramafic rocks and their evolution has been a subject of several studies before, the Spl ultramafics are relatively understudied and can shed new light on the evolution of SNC. The composition of Spl peridotites represents a mixture of typical &amp;#8220;magmatic&amp;#8221; mantle phases with metamorphic minerals (Amph+Chl). Very high Mg# values and occurrence of 120&amp;#176; triple point junctions in Ol (also described in [2]) suggest complex genesis, which probably includes serpentinisation (+exhumation?) followed by deserpentinisation. This indicates that the Spl ultramafics of SNC might have been subducted after their primary serpentinisation, which can be related either to emplacement and exhumation of ultramafics during Rodinia breakup or derivation from shallow, serpentinised &amp;#8220;wet&amp;#8221; mantle wedge in the subduction zone.&amp;#160;&lt;/p&gt;&lt;p&gt;Research founded by Polish National Science Centre grant no. 2019/35/N/ST10/00519.&lt;/p&gt;&lt;p&gt;[1] Gilio et al. (2015). Lithos 230, 1-16.&lt;br&gt;[2] Clos et al. (2014). Lithos 192-195, 8-20.&lt;/p&gt;

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