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Title: Aircraft observations of the chemical composition and aging of aerosol in the Manaus urban plume during GoAmazon 2014/5

Abstract

The Green Ocean Amazon (GoAmazon 2014/5) campaign, conducted fromJanuary 2014 to December 2015 in the vicinity of Manaus, Brazil, was designedto study the aerosol life cycle and aerosol–cloud interactions in bothpristine and anthropogenically influenced conditions. As part of this campaign, the U.S. Department of Energy (DOE) Gulfstream 1 (G-1) research aircraft wasdeployed from 17 February to 25 March 2014 (wet season) and 6 September to5 October 2014 (dry season) to investigate aerosol and cloud propertiesaloft. Here, we present results from the G-1 deployments focusing onmeasurements of the aerosol chemical composition and secondary organicaerosol (SOA) formation and aging. In the first portion of the paper, we provide an overview of the dataand compare and contrast the data from the wet and dry season. Organic aerosol (OA) dominates the deployment-averaged chemical composition,comprising 80% of the non-refractory PM 1 aerosol mass, with sulfatecomprising 14%, nitrate 2%, and ammonium 4%. This productdistribution was unchanged between seasons, despite the fact that totalaerosol loading was significantly higher in the dry season and that regionaland local biomass burning was a significant source of OA mass in the dry,but not wet, season. However, the OA was more oxidized in the dry season,with the median of the mean carbon oxidation state increasing from -0.45more » inthe wet season to -0.02 in the dry season. In the second portion of the paper, we discuss the evolution of theManaus plume, focusing on 13 March 2014, one of the exemplary days in thewet season. On this flight, we observe a clear increase in OA concentrationsin the Manaus plume relative to the background. As the plume is transporteddownwind and ages, we observe dynamic changes in the OA. The mean carbonoxidation state of the OA increases from -0.6 to -0.45 during the 4–5hof photochemical aging. Hydrocarbon-like organic aerosol (HOA) mass is lost,with ΔHOA/ΔCO valuesdecreasing from 17.6µgm -3ppmv -1 over Manaus to 10.6µgm -3ppmv -1 95km downwind.Loss of HOA is balanced out by formation of oxygenated organic aerosol (OOA),with ΔOOA/ΔCO increasing from 9.2 to 23.1µgm -3ppmv -1.Because hydrocarbon-like organic aerosol (HOA) loss is balanced by OOA formation, we observelittle change in the net Δorg/ΔCO values;Δorg/ΔCO averages 31µgm -3ppmv -1 and does notincrease with aging. Analysis of the Manaus plume evolution using data fromtwo additional flights in the wet season showed similar trends in Δorg/ΔCOto the 13 March flight; Δorg/ΔCO valuesaveraged 34µgm -3ppmv -1 and showed little change over4–6.5h of aging. Our observation of constant Δorg/ΔCOare in contrast to literature studies of the outflow of several NorthAmerican cities, which report significant increases inΔorg/ΔCO for the first day of plume aging. These observations suggest that SOAformation in the Manaus plume occurs, at least in part, by a differentmechanism than observed in urban outflow plumes in most other literaturestudies. Constant Δorg/ΔCO with plume aging has beenobserved in many biomass burning plumes, but we are unaware of reports offresh urban emissions aging in this manner. These observations show thaturban pollution emitted from Manaus in the wet season forms less particulatedownwind as it ages than urban pollution emitted from North American cities.« less

Authors:
ORCiD logo [1];  [1];  [2]; ORCiD logo [3];  [4];  [1];  [5]; ORCiD logo [6];  [4]; ORCiD logo [7];  [1]; ORCiD logo [7]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  2. Aerodyne Research, Billerica, MA (United States)
  3. Univ. of Sao Paulo (Brazil)
  4. Harvard Univ., Cambridge, MA (United States)
  5. NASA Goddard Space Flight Center (GSFC), Columbia, MD (United States)
  6. Inst. Nacional de Pesquisas Espaciais, San Jose (Brazil)
  7. Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
OSTI Identifier:
1491165
Alternate Identifier(s):
OSTI ID: 1524544
Report Number(s):
PNNL-SA-132487; BNL-211718-2019-JAAM
Journal ID: ISSN 1680-7324
Grant/Contract Number:  
AC05-76RL01830; SC0012704
Resource Type:
Accepted Manuscript
Journal Name:
Atmospheric Chemistry and Physics (Online)
Additional Journal Information:
Journal Name: Atmospheric Chemistry and Physics (Online); Journal Volume: 18; Journal Issue: 14; Journal ID: ISSN 1680-7324
Publisher:
European Geosciences Union
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 54 ENVIRONMENTAL SCIENCES

Citation Formats

Shilling, John E., Pekour, Mikhail S., Fortner, Edward C., Artaxo, Paulo, de Sá, Suzane, Hubbe, John M., Longo, Karla M., Machado, Luiz A. T., Martin, Scot T., Springston, Stephen R., Tomlinson, Jason, and Wang, Jian. Aircraft observations of the chemical composition and aging of aerosol in the Manaus urban plume during GoAmazon 2014/5. United States: N. p., 2018. Web. doi:10.5194/acp-18-10773-2018.
Shilling, John E., Pekour, Mikhail S., Fortner, Edward C., Artaxo, Paulo, de Sá, Suzane, Hubbe, John M., Longo, Karla M., Machado, Luiz A. T., Martin, Scot T., Springston, Stephen R., Tomlinson, Jason, & Wang, Jian. Aircraft observations of the chemical composition and aging of aerosol in the Manaus urban plume during GoAmazon 2014/5. United States. doi:10.5194/acp-18-10773-2018.
Shilling, John E., Pekour, Mikhail S., Fortner, Edward C., Artaxo, Paulo, de Sá, Suzane, Hubbe, John M., Longo, Karla M., Machado, Luiz A. T., Martin, Scot T., Springston, Stephen R., Tomlinson, Jason, and Wang, Jian. Mon . "Aircraft observations of the chemical composition and aging of aerosol in the Manaus urban plume during GoAmazon 2014/5". United States. doi:10.5194/acp-18-10773-2018. https://www.osti.gov/servlets/purl/1491165.
@article{osti_1491165,
title = {Aircraft observations of the chemical composition and aging of aerosol in the Manaus urban plume during GoAmazon 2014/5},
author = {Shilling, John E. and Pekour, Mikhail S. and Fortner, Edward C. and Artaxo, Paulo and de Sá, Suzane and Hubbe, John M. and Longo, Karla M. and Machado, Luiz A. T. and Martin, Scot T. and Springston, Stephen R. and Tomlinson, Jason and Wang, Jian},
abstractNote = {The Green Ocean Amazon (GoAmazon 2014/5) campaign, conducted fromJanuary 2014 to December 2015 in the vicinity of Manaus, Brazil, was designedto study the aerosol life cycle and aerosol–cloud interactions in bothpristine and anthropogenically influenced conditions. As part of this campaign, the U.S. Department of Energy (DOE) Gulfstream 1 (G-1) research aircraft wasdeployed from 17 February to 25 March 2014 (wet season) and 6 September to5 October 2014 (dry season) to investigate aerosol and cloud propertiesaloft. Here, we present results from the G-1 deployments focusing onmeasurements of the aerosol chemical composition and secondary organicaerosol (SOA) formation and aging. In the first portion of the paper, we provide an overview of the dataand compare and contrast the data from the wet and dry season. Organic aerosol (OA) dominates the deployment-averaged chemical composition,comprising 80% of the non-refractory PM1 aerosol mass, with sulfatecomprising 14%, nitrate 2%, and ammonium 4%. This productdistribution was unchanged between seasons, despite the fact that totalaerosol loading was significantly higher in the dry season and that regionaland local biomass burning was a significant source of OA mass in the dry,but not wet, season. However, the OA was more oxidized in the dry season,with the median of the mean carbon oxidation state increasing from -0.45 inthe wet season to -0.02 in the dry season. In the second portion of the paper, we discuss the evolution of theManaus plume, focusing on 13 March 2014, one of the exemplary days in thewet season. On this flight, we observe a clear increase in OA concentrationsin the Manaus plume relative to the background. As the plume is transporteddownwind and ages, we observe dynamic changes in the OA. The mean carbonoxidation state of the OA increases from -0.6 to -0.45 during the 4–5hof photochemical aging. Hydrocarbon-like organic aerosol (HOA) mass is lost,with ΔHOA/ΔCO valuesdecreasing from 17.6µgm-3ppmv-1 over Manaus to 10.6µgm-3ppmv-1 95km downwind.Loss of HOA is balanced out by formation of oxygenated organic aerosol (OOA),with ΔOOA/ΔCO increasing from 9.2 to 23.1µgm-3ppmv-1.Because hydrocarbon-like organic aerosol (HOA) loss is balanced by OOA formation, we observelittle change in the net Δorg/ΔCO values;Δorg/ΔCO averages 31µgm-3ppmv-1 and does notincrease with aging. Analysis of the Manaus plume evolution using data fromtwo additional flights in the wet season showed similar trends in Δorg/ΔCOto the 13 March flight; Δorg/ΔCO valuesaveraged 34µgm-3ppmv-1 and showed little change over4–6.5h of aging. Our observation of constant Δorg/ΔCOare in contrast to literature studies of the outflow of several NorthAmerican cities, which report significant increases inΔorg/ΔCO for the first day of plume aging. These observations suggest that SOAformation in the Manaus plume occurs, at least in part, by a differentmechanism than observed in urban outflow plumes in most other literaturestudies. Constant Δorg/ΔCO with plume aging has beenobserved in many biomass burning plumes, but we are unaware of reports offresh urban emissions aging in this manner. These observations show thaturban pollution emitted from Manaus in the wet season forms less particulatedownwind as it ages than urban pollution emitted from North American cities.},
doi = {10.5194/acp-18-10773-2018},
journal = {Atmospheric Chemistry and Physics (Online)},
number = 14,
volume = 18,
place = {United States},
year = {2018},
month = {7}
}

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Works referenced in this record:

The Green Ocean Amazon Experiment (GoAmazon2014/5) Observes Pollution Affecting Gases, Aerosols, Clouds, and Rainfall over the Rain Forest
journal, May 2017

  • Martin, S. T.; Artaxo, P.; Machado, L.
  • Bulletin of the American Meteorological Society, Vol. 98, Issue 5, p. 981-997
  • DOI: 10.1175/BAMS-D-15-00221.1