Summary of Organic and Elemental Carbon/Black Carbon Analysis Methods and Intercomparisons

Watson, John G.; Chow, Judith C.; Chen, L.-W. Antony

doi:10.4209/aaqr.2005.06.0006

Cited by 344 publications

(226 citation statements)

References 95 publications

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“…EC represents thermally refractory carbon with a graphitic structure, whereas BC is commonly used to define the extent to which an aerosol sample exhibits light-absorbing properties (Salako et al 2012;Gray and Cass 1998;Huntzicker et al 1982;Watson et al 2005). …”

Section: Introductionmentioning

confidence: 99%

Comparison of elemental and black carbon measurements during normal and heavy haze periods: implications for research

Zhi

Chen

Xue

et al. 2014

Environ Monit Assess

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Studies specifically addressing the elemental carbon (EC)/black carbon (BC) relationship during the transition from clean-normal (CN) air quality to heavy haze (HH) are rare but have important health and climate implications. The present study, in which EC levels are measured using a thermal-optical method and BC levels are measured using an optical method (aethalometer), provides a preliminary insight into this issue. The average daily EC concentration was 3.08±1.10 μg/m 3 during the CN stage but climbed to 11.77±2.01 μg/m 3 during the HH stage. More importantly, the BC/EC ratio averaged 0.92±0.14 during the CN state and increased to 1.88± 0.30 during the HH state. This significant increase in BC/ EC ratio has been confirmed to result partially from an increase in the in situ light absorption efficiency (σ ap ) due to an enhanced internal mixing of the EC with other species. However, the exact enhancement of σ ap was unavailable because our monitoring scheme could not acquire the in situ absorption (b ap ) essential for σ ap calculation. This reveals a need to perform simultaneous measurement of EC and b ap over a time period that includes both the CN and HH stages. In addition, the sensitivity of EC to both anthropogenic emissions and HH conditions implies a need to systematically study how to include EC complex (EC concentration, OC/EC ratio, and σ ap ) as an indicator in air quality observations, in alert systems that assess air quality, and in the governance of emissions and human behaviors.

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Section: Introductionmentioning

confidence: 99%

Comparison of elemental and black carbon measurements during normal and heavy haze periods: implications for research

Zhi

Chen

Xue

et al. 2014

Environ Monit Assess

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“…The variation between the two approaches for OC measured on typical urban and rural samples ranges from about 10 to 30%; for EC the difference can be up to a factor of 2 or more for the different analytical protocols used in the comparison studies (Solomon et al, 2000;Chow et al, 2001;Schmid et al, 2001;Solomon et al, 2003;Chow et al, 2004;Watson et al, 2005;Chow et al, 2008;Cheng et al, 2011). Total carbon (TC), equal to the sum of OC and EC, usually agrees to within 10-15%.…”

Section: Carbonmentioning

confidence: 99%

“…Beginning with samples collected in January 2005, IMPROVE provides both TOR and TOT results (DRI, 2005;Chow et al, 2007). Several studies have been conducted comparing the IMPROVE, CSN, and in some cases other protocols for OC and EC Schmid et al, 2001;Conny et al, 2003;Chow et al, 2004;Watson et al, 2005;Cheng et al, 2011).…”

Section: Carbonmentioning

confidence: 99%

“…The different temperature protocols are shown in Table 4. The different optical approaches occur during the He temperature steps (Chow et al, 1993;Chow et al, 2001;Chow et al, 2004;Chow et al, 2005a;Chow et al, 2007;Peterson and Richards, 2002;Watson et al, 2005;RTI, 2009e). Beginning in 2008 and finishing in 2009, CSN transitioned to the IMPROVE_A analysis protocol to obtain consistency between the networks.…”

Section: Carbonmentioning

confidence: 99%

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U.S. National PM_2.5Chemical Speciation Monitoring Networks—CSN and IMPROVE: Description of networks

Solomon

Crumpler

Flanagan

et al. 2014

Journal of the Air & Waste Management Association

228

173

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“…The PM samples were analyzed for OC and EC with a DRI Model 2001 Thermal/Optical Carbon Analyzer according to the IMPROVE protocol using reflectance for pyrolysis correction Watson et al, 2005). The protocol heats a 0.526 cm 2 punch aliquot of a sample quartz filter stepwise at temperatures of 120 o C (OC1), 250 o C (OC2), 450 o C (OC3), and 550 o C (OC4) in a non-oxidizing helium (He) atmosphere, and 550 o C (EC1), 700 o C (EC2), and 800 o C (EC3) in an oxidizing atmosphere of 2% oxygen in a balance of helium.…”

Section: Chemical Analysismentioning

confidence: 99%

Characterization of Roadside Fine Particulate Carbon and its Eight Fractions in Hong Kong

Cao

Lee

et al. 2006

Aerosol Air Qual. Res.

Self Cite

105

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Simultaneous measurements of PM 2.5 mass, OC and EC and eight carbon fractions were conducted in a roadside microenvironment around Hong Kong for a week in May-June 2002 to obtain the characterization of freshly emitted traffic aerosols. Traffic volume (diesel-powered, liquefied-petroleum gas and gasoline-powered vehicles), meteorological data, and sourcedominated samples were also measured. PM 2.5 samples were collected on pre-fired quartz filters with a mini-volume sampler and a portable fine-particle sampler, then analyzed for OC and EC using thermal optical reflectance (TOR) method, following the IMPROVE protocol. High levels of PM 2.5 mass (64.4 μg m -3 ), OC (16.7 μg m -3 ) and EC (17.1 μg m -3 ) observed in the roadside microenvironment were found to be well-correlated with each other. The average OC/EC ratio was 1.0, indicating that OC and EC were both primary pollutants. Marked diurnal PM 2.5 mass OC and EC concentration profiles were observed in accordance with the traffic pattern (especially for diesel vehicles). Average daytime concentrations were 1.3-1.5 times greater than nighttime values.Carbon profiles from source-dominated samples (diesel, LPG and gasoline vehicles) and diurnal variations of eight carbon fractions (OC1, OC2, OC3, OC4, EC1, EC2, EC3 and OP) demonstrated EC2 and OC2 were the major contributors to the diesel exhaust, and OC3 and OC2were the larger contributors to the LPG and gasoline exhaust. Thus, carbon fractions derived from the IMPROVE protocol could be used to identify different carbon sources.

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Summary of Organic and Elemental Carbon/Black Carbon Analysis Methods and Intercomparisons

Cited by 344 publications

References 95 publications

Comparison of elemental and black carbon measurements during normal and heavy haze periods: implications for research

Comparison of elemental and black carbon measurements during normal and heavy haze periods: implications for research

U.S. National PM_2.5Chemical Speciation Monitoring Networks—CSN and IMPROVE: Description of networks

Characterization of Roadside Fine Particulate Carbon and its Eight Fractions in Hong Kong

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Summary of Organic and Elemental Carbon/Black Carbon Analysis Methods and Intercomparisons

Cited by 344 publications

References 95 publications

Comparison of elemental and black carbon measurements during normal and heavy haze periods: implications for research

Comparison of elemental and black carbon measurements during normal and heavy haze periods: implications for research

U.S. National PM2.5Chemical Speciation Monitoring Networks—CSN and IMPROVE: Description of networks

Characterization of Roadside Fine Particulate Carbon and its Eight Fractions in Hong Kong

Contact Info

Product

Resources

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U.S. National PM_2.5Chemical Speciation Monitoring Networks—CSN and IMPROVE: Description of networks