Harmonizing Aerosol Carbon Measurements between Two Conventional Thermal/Optical Analysis Methods

Zhi, Guorui; Chen, Yingjun; Sun, Junying; Chen, Laiguo; Tian, Wei; Duan, Jiali; Zhang, Gan; Chai, Fahe; Sheng, Guoying; Fu, Jiamo

doi:10.1021/es102803f

Cited by 25 publications

(23 citation statements)

References 54 publications

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“…For example, the average EF EC of bituminous coal briquettes from XF stove is only 40% of those from SC stove (Table S1). Another noteworthy fact is that TOT protocol was used in all previous measurements on coal smoke filter samples, and this brings into a different proportion of OC to EC compared to TOR method, although a tentative relationship between the two protocols was formulated recently (Chow et al, 2001;Zhi et al, 2011).…”

Section: Emission Factors Of Oc and Ecmentioning

confidence: 99%

“…Data inter-conversion may be a good choice between methods. Progress has been made to quantitatively link EC values measured by the two popular thermal/optical protocols, i.e., TOT versus TOR (Zhi et al, 2011). The relationship given in Fig.…”

Section: Future Work On Better Estimation Of Efs For Household Coal Bmentioning

confidence: 99%

“…Secondly, most reported EF data of BC and OC were derived from the thermal-optical analysis (TOA) protocols, either thermal-optical transmittance (TOT) or thermal-optical reflectance (TOR), regardless of the significant difference between the two methods. (Zhi et al, 2011) And more importantly, thermally defined elemental carbon (EC) was usually considered as an equivalent to optical BC in the calculation of emission factor and emission inventory, although there may be a great difference between the two "BC" datasets based on different definitions (Chen et al, 2005;Hammes et al, 2007;Shen et al, 2013c).…”

Section: Introductionmentioning

confidence: 99%

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Measurements of emission factors of PM2.5, OC, EC, and BC for household stoves of coal combustion in China

Chen

Tian

Feng

et al. 2015

Atmospheric Environment

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121

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h i g h l i g h t sCarbonaceous particulate matter emission factors among 20 coal/stove combinations. Dominating factors are coal maturity, burning style and stove efficiency. Optical attenuation cross-section for fresh coal smoke can be deduced as 6.47 m2/g. a r t i c l e i n f o b s t r a c tAs follow-up efforts for measurements on emission factors (EFs) of fine particulate matter (PM 2.5 ) and its carbonaceous fractions for China's household coal stoves, a large-sized dilution sampling system was designed to test a total of 20 coal/stove combinations, which involve five coals with wide-ranged geological maturities and three stoves. Coal smoke was simultaneously collected onto quartz filter for organic carbon (OC) and elemental carbon (EC) analyses by thermal-optical reflectance (TOR) protocol and monitored online for optical black carbon (BC) by Aethalometer. The mean EFs based on burned fuel weight of PM 2.5 , OC, EC, and BC are 4.25 ± 2.45, 1.11 ± 0.72, 1.43 ± 1.17, and 0.60 ± 0.42 g/kg for bituminous coal, and 1.44 ± 0.67, 0.05 ± 0.02, 0.04 ± 0.02, and 0.01 ± 0.01 g/kg for anthracite, respectively. Significant differences are observed among the EFs for various coal/stove combinations, which are attributable to the differences of coal maturity, burning style and stove efficiency. Although the EFs of BC and EC are closely correlated (r ¼ 0.97), the average BC/EC ratio is only 0.39, indicating a significant gap between the two methods; and the optical attenuation cross-section (s) for fresh coal smoke can be deduced as 6.47 m 2 /g, much lower than the manufacturer's preset value of 16.6 m 2 /g for Aethalometer.

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Section: Emission Factors Of Oc and Ecmentioning

confidence: 99%

Section: Future Work On Better Estimation Of Efs For Household Coal Bmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Measurements of emission factors of PM2.5, OC, EC, and BC for household stoves of coal combustion in China

Chen

Tian

Feng

et al. 2015

Atmospheric Environment

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121

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“…A thermal/optical transmission carbon analyzer (Sunset Laboratory Inc.) was employed to divide the filter-loaded particulate carbon into OC and EC (Birch and Cary 1996). The temperature protocol was similar to NIOSH Method 5040 and has been described in our previous publications (Zhi et al 2008(Zhi et al , 2011.…”

Section: Parallel Pm 25 Inlets For An Aethalometer and A Minivol Sammentioning

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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“…Data in panel h were for fresh diesel-powered vehicle emissions. ) are the two most widely used instruments, which are based on the two different protocols i.e., IMPROVE and NIOSH, to determine particulate carbon (Chow et al, 2011;Zhi et al, 2011). Measured L BC values vary significantly among the various instruments and temperature protocols Subramanian et al, 2006;Cheng et al, 2010).…”

Section: Factors Contributing To the Uncertainty Of Mae Measurementmentioning

confidence: 99%

Temporal Variation of Mass Absorption Efficiency of Black Carbon at Urban and Suburban Locations

Wang

Liu

Shi

et al. 2013

Aerosol Air Qual. Res.

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The mass absorption efficiency (MAE) of black carbon (BC) was measured for the ambient aerosols in urban and suburban areas and exhaust plumes from motor vehicles from September 2010 to September 2011 in Xiamen, China. Ambient aerosols, collected on quartz fiber filters, were analyzed for BC loadings using an OC/EC Carbon Aerosol Analyzer and measured for optical attenuations with a laser/LED transmissometer. The MAE of BC in Xiamen shows a large temporal and spatial variability, varying from 0.47 to 5.15 m 2 /g. In the same month (May 2011), the average MAE of BC in suburban area (0.50 m 2 /g) was one third that in urban area (1.50 m 2 /g), suggesting that the variance of MAE was related to the specific emission sources of BC. Here we report the large variation in MAE of BC measured during different sampling times and for different sources in Xiamen. The average MAE was 1.69 m 2 /g and the coefficient of variance was 52%. Factors contributing to the variability were also discussed, as well as the uncertainties caused by different carbon analysis methods, working wavelengths for optical attenuation measurements, and relative humidity when measuring the optical attenuation of the aerosol filters. The results suggest that if a constant value of MAE within the range of 0.47-5.15 m 2 /g is used to quantify the BC concentration, then this would bias the results with a maximum factor of 11. Site-specific values of MAE are recommended for long-term stationary monitoring of ambient BC in air quality monitoring stations.

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Harmonizing Aerosol Carbon Measurements between Two Conventional Thermal/Optical Analysis Methods

Cited by 25 publications

References 54 publications

Measurements of emission factors of PM2.5, OC, EC, and BC for household stoves of coal combustion in China

Measurements of emission factors of PM2.5, OC, EC, and BC for household stoves of coal combustion in China

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

Temporal Variation of Mass Absorption Efficiency of Black Carbon at Urban and Suburban Locations

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