Application of the ECT9 protocol for radiocarbon-based source
apportionment of carbonaceous aerosols

Huang, Lin; Zhang, Wendy; Santos, Guaciara M.; Rodriguez, B.; Holden, S. R.; Vetro, Vincent; Czimczik, C. I.

doi:10.5194/amt-2020-201

Cited by 4 publications

(10 citation statements)

References 18 publications

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“…In addition, individual EC fractions were analyzed for their δ 13 C and ∆ 14 C. To quantify δ 13 C, the EC fraction was isolated from an additional aliquot of the individual aerosol filters or snow filters with the ECT9 protocol, cryogenically trapped, and measured with the cold‐finger mode in an IRMS (MAT 253). The uncertainty of this measurement is about 0.3‰ (Huang et al, 2006, 2020).…”

Section: Methodsmentioning

confidence: 99%

“…Specifically, we quantified the composition of carbonaceous aerosols in airborne particulate matter (PM) and snow at Alert, Canada, between March 2014 and June 2015. To elucidate the chemical properties of the aerosol composition, we isolated OC and EC fractions with the ECT9 protocol (Huang et al, 2006(Huang et al, , 2020. We also combined δ 13 C and Δ 14 C mass balance analyses of the EC fraction with backward trajectory modeling (HYSPLIT) to identify aerosol source sectors and regions.…”

Section: 1029/2020jd033125mentioning

confidence: 99%

“…The analytical accuracy, precision, and linearity range of the ECT9 method are 0.2, 0.1, and 1-17 μg cm −2 , respectively (Huang et al, 2006). The reproducibility of EC/TC ratio is less than 2% (Huang et al, 2020). The concentration of OC was calculated as the sum of OC and POC + CC, while total carbon (TC) was calculated as the sum of the OC, POC + CC, and EC fractions.…”

Section: Carbonaceous Aerosol Analysismentioning

confidence: 99%

“…= not measured (no samples available). OC concentrations are reported as OC total , the sum of OC and pyrolized organic carbon (POC;Huang et al, 2020).…”

mentioning

confidence: 99%

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Seasonal Cycle of Isotope‐Based Source Apportionment of Elemental Carbon in Airborne Particulate Matter and Snow at Alert, Canada

et al. 2020

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Elemental carbon (EC) is a major light-absorbing component of atmospheric aerosol particles. Here, we report the seasonal variation in EC concentrations and sources in airborne particulate matter (PM) and snow at Alert, Canada, from March 2014 to June 2015. We isolated the EC fraction with the EnCan-Total-900 (ECT9) protocol and quantified its stable carbon isotope composition (δ 13 C) and radiocarbon content (Δ 14 C) to apportion EC into contributions from fossil fuel combustion and biomass burning (wildfires and biofuel combustion). Ten-day backward trajectories show EC aerosols reaching Alert by traveling over the Arctic Ocean from the Russian Arctic during winter and from North America (>40°N) during summer. EC concentrations range from 1.8-135.3 ng C m −3 air (1.9-41.2% of total carbon [TC], n = 48), with lowest values in summer (1.8-44.5 ng C m −3 air, n = 9). EC in PM (Δ 14 C =-532 ± 114‰ [ave. ± SD, n = 20]) and snow (−257 ± 131‰, n = 7) was depleted in 14 C relative to current ambient CO 2 year-round. EC in PM mainly originated from liquid and solid fossil fuels from fall to spring (47-70% fossil), but had greater contributions from biomass burning in summer (48-80% modern carbon). EC in snow was mostly from biomass burning (53-88%). Our data show that biomass burning EC is preferentially incorporated into snow because of scavenging processes within the Arctic atmosphere or long-range transport in storm systems. This work provides a comprehensive view of EC particles captured in the High Arctic through wet and dry deposition and demonstrates that surface stations monitoring EC in PM might underestimate biomass burning and transport. Plain Language Summary Elemental carbon (EC) aerosols are produced during combustion processes and impact Arctic climate because they absorb light, warm the atmosphere, and accelerate snow and ice melt. Here, we measured the concentration and isotopic composition of EC suspended in the atmosphere and in snow at Alert, Canada, between March 2014 and May 2015. We found that concentrations were lowest during the summer and increased throughout the winter and early spring. This pattern is typical, because EC is removed from the atmosphere by precipitation, which happens more frequently during summer. Our isotope data and meteorological analyses revealed that fossil fuel burning in the Russian Arctic was an important source of EC to Alert from September to May, while forest fires in the North American boreal region were major sources of EC during the summer. We also found that snow contained a greater proportion of EC derived from biomass burning than the suspended aerosols. Snow might be preferentially capturing biomass burning EC from the local atmosphere or be transporting them to the Arctic from lower latitudes. Since EC surface observing networks routinely measure EC in PM but not snow, the impact of biomass burning EC sources on Arctic climate might be underestimated.

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Section: Methodsmentioning

confidence: 99%

Section: 1029/2020jd033125mentioning

confidence: 99%

Section: Carbonaceous Aerosol Analysismentioning

confidence: 99%

“…= not measured (no samples available). OC concentrations are reported as OC total , the sum of OC and pyrolized organic carbon (POC;Huang et al, 2020).…”

mentioning

confidence: 99%

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Seasonal Cycle of Isotope‐Based Source Apportionment of Elemental Carbon in Airborne Particulate Matter and Snow at Alert, Canada

et al. 2020

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“…The graphite was then pressed into aluminum holders and loaded into the AMS unit alongside measurement standards (Table S6) and blanks for 14 C measurement (Beverly et al, 2010). The data are reported as a fraction of modern carbon (F 14 C), following the conventions established by Stuiver and Polach (1977) and also described elsewhere (Reimer et al, 2004;Trumbore et al, 2016).…”

Section: C Measurementsmentioning

confidence: 99%

Application of the ECT9 protocol for radiocarbon-based source apportionment of carbonaceous aerosols

et al. 2021

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Abstract. Carbonaceous aerosol is mainly composed of organic carbon (OC) and elemental carbon (EC). Both OC and EC originate from a variety of emission sources. Radiocarbon (14C) analysis can be used to apportion bulk aerosol, OC, and EC into their sources. However, such analyses require the physical separation of OC and EC. Here, we apply of ECT9 protocol to physically isolate OC and EC for 14C analysis and evaluate its effectiveness. Several reference materials are selected, including two pure OC (fossil “adipic acid” and contemporary “sucrose”), two pure EC (fossil “regal black” and “C1150”), and three complex materials containing contemporary and/or fossil OC and EC (“rice char”, NIST urban dust standards “SRM1649a” and “SRM8785”, i.e., fine fraction of resuspended SRM1649a on filters). The pure materials were measured for their OC, EC, and total carbon (TC) mass fractions and corresponding carbon isotopes to evaluate the uncertainty of the procedure. The average accuracy of TC mass, determined via volumetric injection of a sucrose solution, was approximately 5 %. Ratios of EC/TC and OC/TC were highly reproducible, with analytical precisions better than 2 % for all reference materials, ranging in size from 20 to 100 µg C. Consensus values were reached for all pure reference materials for both δ13C and fraction modern (F14C), with an uncertainty of < 0.3 ‰ and approximately 5 %, respectively. The procedure introduced 1.3 ± 0.6 µg of extraneous carbon, an amount compatible to that of the Swiss_4S protocol. In addition, OC and EC were isolated from mixtures of pure contemporary OC (sucrose) with pure fossil EC (regal black) and fossil OC (adipic acid) with contemporary EC (rice char EC) to evaluate the effectiveness of OC and EC separation. Consensus F14C values were reached for all OC (∼ 5–30 µg) and EC (∼ 10–60 µg) fractions with an uncertainty of ∼ 5 % on average. We found that the ECT9 protocol efficiently isolates OC or EC from complex mixtures. Based on δ13C measurements, the average contribution of charred OC to EC is likely less than 3 % when the OC loading amount is less than 30 µg C. Charring was further assessed by evaluating thermograms of various materials, including aerosol samples collected in the Arctic and from tailpipes of gasoline or diesel engines. These data demonstrate that the ECT9 method effectively removes pyrolyzed OC. Thus, the ECT9 protocol, initially developed for concentration and stable isotope measurements of OC and EC, is suitable for 14C-based apportionment studies, including µg C-sized samples from arctic environments.

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Radiocarbon dating

Hajdas

Ascough

Garnett

et al. 2021

Nat Rev Methods Primers

125

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Radiocarbon dating uses the decay of a radioactive isotope of carbon ( 14 C) to measure time and date objects containing carbon-bearing material. With a half-life of 5,700 ± 30 years, detection of 14 C is a useful tool for determining the age of a specimen formed over the last 55,000 years. In this Primer, we outline key advances in 14 C measurement and instrument capacity, as well as optimal sample selection and preparation. We discuss data processing,

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Application of the ECT9 protocol for radiocarbon-based source apportionment of carbonaceous aerosols

Cited by 4 publications

References 18 publications

Seasonal Cycle of Isotope‐Based Source Apportionment of Elemental Carbon in Airborne Particulate Matter and Snow at Alert, Canada

Seasonal Cycle of Isotope‐Based Source Apportionment of Elemental Carbon in Airborne Particulate Matter and Snow at Alert, Canada

Application of the ECT9 protocol for radiocarbon-based source apportionment of carbonaceous aerosols

Radiocarbon dating

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