Examination of brown carbon absorption from wildfires in the western US during the WE-CAN study
<p>Light absorbing organic carbon, or brown carbon (BrC), can be a significant contributor to the visible light absorption budget. However, the sources of BrC and the contributions of BrC to light absorption are not well understood. Biomass burning is thought to be a major source of BrC. There...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2022-10-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/22/13389/2022/acp-22-13389-2022.pdf |
| _version_ | 1798030104014618624 |
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| author | A. P. Sullivan R. P. Pokhrel R. P. Pokhrel R. P. Pokhrel Y. Shen S. M. Murphy D. W. Toohey T. Campos J. Lindaas E. V. Fischer J. L. Collett Jr. |
| author_facet | A. P. Sullivan R. P. Pokhrel R. P. Pokhrel R. P. Pokhrel Y. Shen S. M. Murphy D. W. Toohey T. Campos J. Lindaas E. V. Fischer J. L. Collett Jr. |
| author_sort | A. P. Sullivan |
| collection | DOAJ |
| description | <p>Light absorbing organic carbon, or brown carbon (BrC), can be a significant
contributor to the visible light absorption budget. However, the sources of
BrC and the contributions of BrC to light absorption are not well
understood. Biomass burning is thought to be a major source of BrC.
Therefore, as part of the WE-CAN (Western Wildfire Experiment for Cloud
Chemistry, Aerosol Absorption and Nitrogen) study, BrC absorption data were
collected on board the National Science Foundation/National Center for Atmospheric Research (NSF/NCAR) C-130 aircraft as it intercepted smoke from
wildfires in the western US in July–August 2018. BrC absorption
measurements were obtained in near real-time using two techniques. The first
coupled a particle-into-liquid sampler (PILS) with a liquid waveguide
capillary cell and a total organic carbon analyzer for measurements of
water-soluble BrC absorption and WSOC (water-soluble organic carbon). The
second employed a custom-built photoacoustic aerosol absorption spectrometer
(PAS) to measure total absorption at 405 and 660 nm. The PAS BrC absorption at 405 nm (PAS total Abs 405 BrC) was calculated by assuming the absorption determined by the PAS at 660 nm was equivalent to the black carbon (BC) absorption and the BC aerosol absorption Ångström exponent was 1. Data from the PILS and PAS were combined to investigate the water-soluble vs. total BrC absorption at 405 nm in the various wildfire plumes sampled during WE-CAN. WSOC, PILS water-soluble Abs 405, and PAS total Abs 405 tracked each other in and out of the smoke plumes. BrC absorption was correlated with WSOC (<span class="inline-formula"><i>R</i><sup>2</sup></span> value for PAS <span class="inline-formula">=0.42</span> and PILS <span class="inline-formula">=0.60</span>) and CO (carbon monoxide) (<span class="inline-formula"><i>R</i><sup>2</sup></span> value for PAS <span class="inline-formula">=0.76</span> and PILS <span class="inline-formula">=0.55</span>) for all wildfires sampled. The PILS water-soluble Abs 405 was corrected for the
non-water-soluble fraction of the aerosol using the calculated UHSAS
(ultra-high-sensitivity aerosol spectrometer) aerosol mass. The corrected
PILS water-soluble Abs 405 showed good closure with the PAS total Abs 405
BrC with a factor of <span class="inline-formula">∼1.5</span> to 2 difference. This difference
was explained by particle vs. bulk solution absorption measured by the PAS
vs. PILS, respectively, and confirmed by Mie theory calculations. During
WE-CAN, <span class="inline-formula">∼</span> 45 % (ranging from 31 % to 65 %) of the BrC
absorption was observed to be due to water-soluble species. The ratio of BrC absorption to WSOC or <span class="inline-formula">ΔCO</span> showed no clear dependence on fire
dynamics or the time since emission over 9 h.</p> |
| first_indexed | 2024-04-11T19:34:48Z |
| format | Article |
| id | doaj.art-19e9fee3748140859d0855929d4a0e1e |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-04-11T19:34:48Z |
| publishDate | 2022-10-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-19e9fee3748140859d0855929d4a0e1e2022-12-22T04:06:53ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242022-10-0122133891340610.5194/acp-22-13389-2022Examination of brown carbon absorption from wildfires in the western US during the WE-CAN studyA. P. Sullivan0R. P. Pokhrel1R. P. Pokhrel2R. P. Pokhrel3Y. Shen4S. M. Murphy5D. W. Toohey6T. Campos7J. Lindaas8E. V. Fischer9J. L. Collett Jr.10Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523, USADepartment of Atmospheric Science, University of Wyoming, Laramie, WY 82071, USAnow at: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USANOAA Chemical Science Laboratory, Boulder, CO 80305, USADepartment of Atmospheric Science, University of Wyoming, Laramie, WY 82071, USADepartment of Atmospheric Science, University of Wyoming, Laramie, WY 82071, USADepartment of Atmospheric and Oceanic Sciences, University of Colorado – Boulder, Boulder, CO 80309, USAAtmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, CO 80307, USADepartment of Atmospheric Science, Colorado State University, Fort Collins, CO 80523, USADepartment of Atmospheric Science, Colorado State University, Fort Collins, CO 80523, USADepartment of Atmospheric Science, Colorado State University, Fort Collins, CO 80523, USA<p>Light absorbing organic carbon, or brown carbon (BrC), can be a significant contributor to the visible light absorption budget. However, the sources of BrC and the contributions of BrC to light absorption are not well understood. Biomass burning is thought to be a major source of BrC. Therefore, as part of the WE-CAN (Western Wildfire Experiment for Cloud Chemistry, Aerosol Absorption and Nitrogen) study, BrC absorption data were collected on board the National Science Foundation/National Center for Atmospheric Research (NSF/NCAR) C-130 aircraft as it intercepted smoke from wildfires in the western US in July–August 2018. BrC absorption measurements were obtained in near real-time using two techniques. The first coupled a particle-into-liquid sampler (PILS) with a liquid waveguide capillary cell and a total organic carbon analyzer for measurements of water-soluble BrC absorption and WSOC (water-soluble organic carbon). The second employed a custom-built photoacoustic aerosol absorption spectrometer (PAS) to measure total absorption at 405 and 660 nm. The PAS BrC absorption at 405 nm (PAS total Abs 405 BrC) was calculated by assuming the absorption determined by the PAS at 660 nm was equivalent to the black carbon (BC) absorption and the BC aerosol absorption Ångström exponent was 1. Data from the PILS and PAS were combined to investigate the water-soluble vs. total BrC absorption at 405 nm in the various wildfire plumes sampled during WE-CAN. WSOC, PILS water-soluble Abs 405, and PAS total Abs 405 tracked each other in and out of the smoke plumes. BrC absorption was correlated with WSOC (<span class="inline-formula"><i>R</i><sup>2</sup></span> value for PAS <span class="inline-formula">=0.42</span> and PILS <span class="inline-formula">=0.60</span>) and CO (carbon monoxide) (<span class="inline-formula"><i>R</i><sup>2</sup></span> value for PAS <span class="inline-formula">=0.76</span> and PILS <span class="inline-formula">=0.55</span>) for all wildfires sampled. The PILS water-soluble Abs 405 was corrected for the non-water-soluble fraction of the aerosol using the calculated UHSAS (ultra-high-sensitivity aerosol spectrometer) aerosol mass. The corrected PILS water-soluble Abs 405 showed good closure with the PAS total Abs 405 BrC with a factor of <span class="inline-formula">∼1.5</span> to 2 difference. This difference was explained by particle vs. bulk solution absorption measured by the PAS vs. PILS, respectively, and confirmed by Mie theory calculations. During WE-CAN, <span class="inline-formula">∼</span> 45 % (ranging from 31 % to 65 %) of the BrC absorption was observed to be due to water-soluble species. The ratio of BrC absorption to WSOC or <span class="inline-formula">ΔCO</span> showed no clear dependence on fire dynamics or the time since emission over 9 h.</p>https://acp.copernicus.org/articles/22/13389/2022/acp-22-13389-2022.pdf |
| spellingShingle | A. P. Sullivan R. P. Pokhrel R. P. Pokhrel R. P. Pokhrel Y. Shen S. M. Murphy D. W. Toohey T. Campos J. Lindaas E. V. Fischer J. L. Collett Jr. Examination of brown carbon absorption from wildfires in the western US during the WE-CAN study Atmospheric Chemistry and Physics |
| title | Examination of brown carbon absorption from wildfires in the western US during the WE-CAN study |
| title_full | Examination of brown carbon absorption from wildfires in the western US during the WE-CAN study |
| title_fullStr | Examination of brown carbon absorption from wildfires in the western US during the WE-CAN study |
| title_full_unstemmed | Examination of brown carbon absorption from wildfires in the western US during the WE-CAN study |
| title_short | Examination of brown carbon absorption from wildfires in the western US during the WE-CAN study |
| title_sort | examination of brown carbon absorption from wildfires in the western us during the we can study |
| url | https://acp.copernicus.org/articles/22/13389/2022/acp-22-13389-2022.pdf |
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