scholarly journals Analysis of elemental carbon and organic carbon by the thermal method.

1986 ◽  
Vol 15 (9) ◽  
pp. 713-718
Author(s):  
Hisao ARAI
Keyword(s):  
Organic Carbon ◽  
Elemental Carbon ◽  
Thermal Method

scholarly journals Evaluation of a 2-step thermal method for separating organic and elemental carbon for radiocarbon analysis

2014 ◽  
Vol 7 (1) ◽  
pp. 131-169 ◽  
Author(s):  
U. Dusek ◽  
M. Monaco ◽  
M. Prokopiou ◽  
F. Gongriep ◽  
R. Hitzenberger ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Humic Acid ◽  
Organic Carbon ◽  
Organic Compounds ◽  
Strong Evidence ◽  
Elemental Carbon ◽  
Intermediate Temperature ◽  
Thermal Method ◽  
Intermediate Step ◽  
Temperature Step

Abstract. We thoroughly characterized a system for thermal separation of organic carbon (OC) and elemental carbon (EC) for subsequent radiocarbon analysis. Different organic compounds as well as ambient aerosol filter samples were introduced into an oven system and combusted to CO2 in pure O2. The main objective was to test which combustion times and temperatures are best suited to separate OC and EC. The final separation step for OC was combustion at 360 °C for 15 min. Combustion at this temperature proved enough to remove several organic test substances from the filter (including high molecular weight humic acid) but did not remove substantial amounts of EC. For isolation of EC, OC first needs to be completely removed from the filter. This was achieved by water extraction of the filter, followed by combustion of the water insoluble OC at 360 °C and combustion at an intermediate temperature step of 2 min at 450 °C. This last step removed the most refractory OC together with some EC. Finally, the remaining EC was combusted to CO2 at 650 °C. The recovery of black carbon after the intermediate 450 °C step was approximately 80%. Several tests provided strong evidence that OC was removed efficiently during the intermediate temperature step: (i) brown carbon, indicative of refractory OC, was removed; (ii) the fraction modern of EC did not decrease significantly if the temperature of the intermediate step was further increased. Based on tests with various organic compounds, we estimated that charred organic carbon could contribute 4–8% to an elemental carbon sample that was isolated according to our method.

scholarly journals Evaluation of a two-step thermal method for separating organic and elemental carbon for radiocarbon analysis

2014 ◽  
Vol 7 (7) ◽  
pp. 1943-1955 ◽  
Author(s):  
U. Dusek ◽  
M. Monaco ◽  
M. Prokopiou ◽  
F. Gongriep ◽  
R. Hitzenberger ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Humic Acid ◽  
Organic Carbon ◽  
Organic Compounds ◽  
Strong Evidence ◽  
Elemental Carbon ◽  
Intermediate Temperature ◽  
Thermal Method ◽  
Intermediate Step ◽  
Temperature Step

Abstract. We thoroughly characterized a system for thermal separation of organic carbon (OC) and elemental carbon (EC) for subsequent radiocarbon analysis. Different organic compounds as well as ambient aerosol filter samples were introduced into an oven system and combusted to CO2 in pure O2. The main objective was to test which combustion times and temperatures are best suited to separate OC and EC. The final separation step for OC was combustion at 360 °C for 15 min. Combustion at this temperature proved enough to remove several organic test substances from the filter (including high molecular weight humic acid) but did not remove substantial amounts of EC. For isolation of EC, OC first needs to be completely removed from the filter. This was achieved by water extraction of the filter, followed by combustion of the water insoluble OC at 360 °C and combustion at an intermediate temperature step of 2 min at 450 °C. This last step removed the most refractory OC together with some EC. Finally, the remaining EC was combusted to CO2 at 650 °C. The recovery of black carbon after the intermediate 450 °C step was approximately 80%. Several tests provided strong evidence that OC was removed efficiently during the intermediate temperature step: (i) brown carbon, indicative of refractory OC, was removed; (ii) the fraction modern of EC did not decrease significantly if the temperature of the intermediate step was further increased. Based on tests with various organic compounds, we estimated that charred organic carbon could contribute 4–8% to an elemental carbon sample that was isolated according to our method.

Ambient organic carbon to elemental carbon ratios: Influence of the thermal–optical temperature protocol and implications

2014 ◽  
Vol 468-469 ◽  
pp. 1103-1111 ◽  
Author(s):  
Yuan Cheng ◽  
Ke-bin He ◽  
Feng-kui Duan ◽  
Zhen-yu Du ◽  
Mei Zheng ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Elemental Carbon

scholarly journals Inter-comparison of elemental and organic carbon mass measurements from three North American national long-term monitoring networks at a co-located site

2019 ◽  
Vol 12 (8) ◽  
pp. 4543-4560 ◽  
Author(s):  
Tak W. Chan ◽  
Lin Huang ◽  
Kulbir Banwait ◽  
Wendy Zhang ◽  
Darrell Ernst ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Forest Fire ◽  
Monitoring Network ◽  
Total Carbon ◽  
Carbonaceous Aerosol ◽  
Thermal Method ◽  
Monitoring Networks ◽  
Sample Collection ◽  
Fire Emissions ◽  
Additional Information

Abstract. Carbonaceous aerosol is a major contributor to the total aerosol load and being monitored by diverse measurement approaches. Here, 10 years (2005–2015) of continuous carbonaceous aerosol measurements collected at the Centre of Atmospheric Research Experiments (CARE) in Egbert, Ontario, Canada, on quartz-fiber filters by three independent networks (Interagency Monitoring of Protected Visual Environments, IMPROVE; Canadian Air and Precipitation Monitoring Network, CAPMoN; and Canadian Aerosol Baseline Measurement, CABM) were compared. Specifically, the study evaluated how differences in sample collection and analysis affected the concentrations of total carbon (TC), organic carbon (OC), and elemental carbon (EC). Results show that different carbonaceous fractions measured by various networks were consistent and comparable in general among the three networks over the 10-year period, even with different sampling systems/frequencies, analytical protocols, and artifact corrections. The CAPMoN TC, OC, and EC obtained from the DRI model 2001 thermal–optical carbon analyzer following the IMPROVE-TOR protocol (denoted as DRI-TOR) method were lower than those determined from the IMPROVE_A TOR method by 17 %, 14 %, and 18 %, respectively. When using transmittance for charring correction, the corresponding carbonaceous fractions obtained from the Sunset-TOT were lower by as much as 30 %, 15 %, and 75 %, respectively. In comparison, the CABM TC, OC, and EC obtained from a thermal method, EnCan-Total-900 (ECT9), were higher than the corresponding fractions from IMPROVE_A TOR by 20 %–30 %, 0 %–15 %, and 60 %–80 %, respectively. Ambient OC and EC concentrations were found to increase when ambient temperature exceeded 10 ∘C. These increased ambient concentrations of OC during summer were possibly attributed to secondary organic aerosol (SOA) formation and forest fire emissions, while elevated EC concentrations were potentially influenced by forest fire emissions and increased vehicle emissions. Results also show that the pyrolyzed organic carbon (POC) obtained from the ECT9 protocol could provide additional information on SOA although more research is still needed.

scholarly journals High contributions of fossil sources to more volatile organic aerosol

2019 ◽  
Vol 19 (15) ◽  
pp. 10405-10422 ◽  
Author(s):  
Haiyan Ni ◽  
Ru-Jin Huang ◽  
Junji Cao ◽  
Wenting Dai ◽  
Jiamao Zhou ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Elemental Carbon ◽  
Organic Aerosol ◽  
Formation Mechanisms ◽  
Formation Processes ◽  
Combustion System ◽  
Relative Contribution ◽  
Custom Made ◽  
Volatile Organic ◽  
Volatile Carbon

Abstract. Sources of particulate organic carbon (OC) with different volatility have rarely been investigated, despite the significant importance for better understanding of the atmospheric processes of organic aerosols. In this study we develop a radiocarbon-based (14C) approach for source apportionment of more volatile OC (mvOC) and apply to ambient aerosol samples collected in winter in six Chinese megacities. mvOC is isolated by desorbing organic carbon from the filter samples in helium (He) at 200 ∘C in a custom-made aerosol combustion system for 14C analysis. Evaluation of this new isolation method shows that the isolated mvOC amount agrees very well with the OC1 fraction (also desorbed at 200 ∘C in He) measured by a thermal–optical analyzer using the EUSAAR_2 protocol. The mvOC, OC and elemental carbon (EC) of 13 combined PM2.5 samples in six Chinese cities are analyzed for 14C to investigate their sources and formation mechanisms. The relative contribution of fossil sources to mvOC is 59±11 %, consistently larger than the contribution to OC (48±16 %) and smaller than that to EC (73±9 %), despite large differences in fossil contributions in different cities. The average difference in the fossil fractions between mvOC and OC is 13 % (range of 7 %–25 %), similar to that between mvOC and EC (13 %, with a range 4 %–25 %). Secondary OC (SOC) concentrations and sources are modeled based on the 14C-apportioned OC and EC and compared with concentrations and sources of mvOC. SOC concentrations (15.4±9.0 µg m−3) are consistently higher than those of mvOC (3.3±2.2 µg m−3), indicating that only a fraction of SOC is accounted for by the more volatile carbon fraction desorbed at 200 ∘C. The fossil fraction in SOC is 43 % (10 %–70 %), lower than that in mvOC (59 %, with a range of 45 %–78 %). Correlation between mvOC and SOC from nonfossil sources (mvOCnf vs. SOCnf) and from fossil sources (mvOCfossil vs. SOCfossil) is examined to further explore sources and formation processes of mvOC and SOC.

scholarly journals Sources of PM<sub>2.5</sub> carbonaceous aerosol in Riyadh, Saudi Arabia

2017 ◽  
Author(s):  
Qijing Bian ◽  
Badr Alharbi ◽  
Mohammed M. Sharee ◽  
Tahir Husai ◽  
Mohammad J. Pasha ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Air Quality ◽  
Organic Carbon ◽  
Pollution Control ◽  
Elemental Carbon ◽  
Control Strategies ◽  
Continuous Method ◽  
Carbonaceous Aerosol ◽  
Abstract Knowledge ◽  
The City

Abstract. Knowledge of the sources of carbonaceous aerosol affecting air quality in Riyadh, Saudi Arabia is limited, but needed for the development of pollution control strategies. We conducted sampling of PM2.5 from April to September, 2012 at various sites in the city, and used a thermo-optical semi-continuous method to quantify the organic carbon (OC) and elemental carbon (EC) concentrations. The average OC and EC concentrations were 4.7 ± 4.4 and 2.1 ± 2.5 μg  m

Isotopic composition of organic carbon and elemental carbon in PM2.5 in Hangzhou, China

2007 ◽  
Vol 52 (17) ◽  
pp. 2435-2437 ◽  
Author(s):  
Gang Liu ◽  
XuXian Zhang ◽  
WeiLin Teng ◽  
Hui Yang
Keyword(s):  
Organic Carbon ◽  
Isotopic Composition ◽  
Elemental Carbon
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