scholarly journals Elemental Carbon and Its Fractions during Evolved Gas Analysis with Respect to Pyrolytic Carbon and Split Time

2021 ◽  
Vol 11 (16) ◽  
pp. 7544
Author(s):  
Juhan Lee ◽  
Dohyun Kim ◽  
Jeonghoon Lee
Keyword(s):  
Black Carbon ◽  
Elemental Carbon ◽  
Evolved Gas Analysis ◽  
Pyrolytic Carbon ◽  
Gas Analysis ◽  
Oxidation Temperature ◽  
Carbon Oxidation ◽  
Evolved Gas ◽  
Helium Mixture ◽  
Split Time

We demonstrated the relationships between elemental carbon (EC) and EC fractions during evolved gas analysis (EGA) for PM2.5 sampled at KOREATECH from 29 March 2018 to 12 May 2018. The EC concentrations were compared to the concentrations of equivalent black carbon to confirm that the level of EC concentrations analyzed in this study was valid. Among various EC fractions and their combination, EC1+EC3 fractions were best correlated with the EC concentrations. Especially, dominant EC fraction was related with the dependence of carbon oxidation quantity on the oxidation temperature. We also examined the relationships between pyrolytic carbon (PyC) and EC concentration with respect to the split time. PyC was correlated with the split time in the phase of oxygen-helium mixture. PyC was close to zero for the split time in the helium phase. It is novel, as far as the authors know, that the correlation between PyC and the split time under NIOSH 5040 protocol was reported with regard to EGA. We believe that our study helps to identify what causes uncertainty in the quantification of PyC.

scholarly journals The effect of metal salts on quantification of elemental and organic carbon in diesel exhaust particles using thermal-optical evolved gas analysis

2010 ◽  
Vol 10 (23) ◽  
pp. 11447-11457 ◽  
Author(s):  
Y. Wang ◽  
A. Chung ◽  
S. E. Paulson
Keyword(s):  
Organic Carbon ◽  
Alkaline Earth ◽  
Metal Salt ◽  
Evolved Gas Analysis ◽  
Gas Analysis ◽  
Diesel Exhaust Particles ◽  
Metal Salts ◽  
Oxidation Temperature ◽  
Carbonaceous Aerosols ◽  
Evolved Gas

Abstract. Thermal-optical evolved gas analysis (TOEGA) is a conventional method for classifying carbonaceous aerosols as organic carbon (OC) and elemental carbon (EC). Its main source of uncertainty arises from accounting for pyrolized OC (char), which has similar behavior to the EC originally present on the filter. Sample composition can also cause error, at least partly by complicating the charred carbon correction. In this study, lab generated metal salt particles, including alkali (NaCl, KCl, Na2SO4), alkaline-earth (MgCl2, CaCl2) and transition metal salts (CuCl2, FeCl2, FeCl3, CuCl, ZnCl2, MnCl2, CuSO4, Fe2(SO4)3), were deposited on a layer of diesel particles to investigate their effect on EC and OC quantification with TOEGA. Measurements show that metals reduce the oxidation temperature of EC and enhance the charring of OC. The split point used to determine classification of EC vs. OC is more dependent on changes in EC oxidation temperature than it is on charring. The resulting EC/OC ratio is reduced by 0–80% in the presence of most of the salts, although some metal salts increase reported EC/OC at low metal to carbon ratios. The results imply that EC/OC ratios of ambient aerosols quantified with TOEGA have variable low biases due to the presence of metals. In general, transition metals are more active than alkali and alkaline-earth metals; copper is the most active. Copper and iron chlorides are more active than sulfates. The melting point of metal salts is strongly correlated with the increase of OC charring, but not with the reduction of EC oxidation temperature. Other chemistry, such as redox reactions, may affect the EC oxidation. A brief discussion of possible catalytic mechanisms for the metals is provided.

scholarly journals The effect of metal salts on quantification of elemental and organic carbon in diesel exhaust particles using thermal-optical evolved gas analysis

2010 ◽  
Vol 10 (7) ◽  
pp. 16941-16968
Author(s):  
Y. Wang ◽  
A. Chung ◽  
S. E. Paulson
Keyword(s):  
Organic Carbon ◽  
Alkaline Earth ◽  
Metal Salt ◽  
Evolved Gas Analysis ◽  
Gas Analysis ◽  
Diesel Exhaust Particles ◽  
Metal Salts ◽  
Oxidation Temperature ◽  
Carbonaceous Aerosols ◽  
Evolved Gas

Abstract. Thermal-optical evolved gas analysis (TOEGA) is a conventional method for classifying carbonaceous aerosols as organic carbon (OC) and elemental carbon (EC). Its main source of uncertainty arises from accounting for pyrolyzed OC (char), which has similar behavior to the EC originally present on the filter. Sample composition can also cause error, at least partly by complicating the charred carbon correction. In this study, lab generated metal salt particles, including alkali (NaCl, KCl, Na2SO4), alkaline-earth (MgCl2, CaCl2) and transition metal salts (CuCl2, FeCl2, FeCl3, CuCl, ZnCl2, MnCl2, CuSO4, Fe2(SO4)3), were deposited on a layer of diesel particles to investigate their effect on EC and OC quantification with TOEGA. Measurements show that metals reduce the oxidation temperature of EC and enhance the charring of OC. The split point used to determine classification of EC vs. OC is more dependent on changes in EC oxidation temperature than it was on charring. The resulting EC/OC ratio is reduced by 0–80% in the presence of most of the salts, although some metal salts increased reported EC/OC at low metal to carbon ratios. In general, transition metals are more active than alkali and alkaline-earth metals; copper is the most active. Copper and iron chlorides are more active than sulfates. The melting point of metal salts is strongly correlated with the increase of OC charring, but not with the reduction of EC oxidation temperature. Other chemistry, such as redox reactions, may affect the EC oxidation. A brief discussion of possible catalytic mechanisms for the metals is provided.

Evolved Gas Analysis by Infrared Spectroscopy

2010 ◽  
Vol 45 (4) ◽  
pp. 241-273 ◽  
Author(s):  
S. Materazzi ◽  
S. Vecchio
Keyword(s):  
Infrared Spectroscopy ◽  
Evolved Gas Analysis ◽  
Gas Analysis ◽  
Evolved Gas
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