Document Type

Article

Publication Date

7-2018

Publication Title

Atmospheric Chemistry and Physics

ISSN

1680-7324

Volume

18

Issue

14

DOI

http://dx.doi.org/10.5194/acp-18-10433-2018

Abstract

Biogenic volatile organic compounds (BVOCs) from the Amazon forest region represent the largest source of organic carbon emissions to the atmosphere globally. These BVOC emissions dominantly consist of volatile and intermediate-volatility terpenoid compounds that undergo chemical transformations in the atmosphere to form oxygenated condensable gases and secondary organic aerosol (SOA). We collected quartz filter samples with 12 h time resolution and performed hourly in situ measurements with a semi-volatile thermal desorption aerosol gas chromatograph (SV-TAG) at a rural site (T3) located to the west of the urban center of Manaus, Brazil as part of the Green Ocean Amazon (GoAmazon2014/5) field campaign to measure intermediate-volatility and semi-volatile BVOCs and their oxidation products during the wet and dry seasons. We speciated and quantified 30 sesquiterpenes and 4 diterpenes with mean concentrations in the range 0.01–6.04 ng m−3 (1–670 ppqv). We estimate that sesquiterpenes contribute approximately 14 and 12 % to the total reactive loss of O3 via reaction with isoprene or terpenes during the wet and dry seasons, respectively. This is reduced from  ∼  50–70 % for within-canopy reactive O3 loss attributed to the ozonolysis of highly reactive sesquiterpenes (e.g., β-caryophyllene) that are reacted away before reaching our measurement site. We further identify a suite of their oxidation products in the gas and particle phases and explore their role in biogenic SOA formation in the central Amazon region. Synthesized authentic standards were also used to quantify gas- and particle-phase oxidation products derived from β-caryophyllene. Using tracer-based scaling methods for these products, we roughly estimate that sesquiterpene oxidation contributes at least 0.4–5 % (median 1 %) of total submicron OA mass. However, this is likely a low-end estimate, as evidence for additional unaccounted sesquiterpenes and their oxidation products clearly exists. By comparing our field data to laboratory-based sesquiterpene oxidation experiments we confirm that more than 40 additional observed compounds produced through sesquiterpene oxidation are present in Amazonian SOA, warranting further efforts towards more complete quantification.

Comments

Lindsay D. Yee1, Gabriel Isaacman-VanWertz1,a, Rebecca A. Wernis2, Meng Meng3,b,Ventura Rivera3, Nathan M. Kreisberg4, Susanne V. Hering4, Mads S. Bering5,Marianne Glasius5, Mary Alice Upshur6, Ariana Gray Bé6, Regan J. Thomson6,Franz M. Geiger6, John H. Offenberg7, Michael Lewandowski7, Ivan Kourtchev8,Markus Kalberer8, Suzane de Sá9, Scot T. Martin9,10, M. Lizabeth Alexander11,Brett B. Palm12, Weiwei Hu12, Pedro Campuzano-Jost12, Douglas A. Day12,Jose L. Jimenez12, Yingjun Liu9,c, Karena A. McKinney9,d, Paulo Artaxo13,Juarez Viegas14, Antonio Manzi14, Maria B. Oliveira15, Rodrigo de Souza15,Luiz A. T. Machado16, Karla Longo17, and Allen H. Goldstein1

1Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, California 94720, USA
2Department of Civil and Environmental Engineering, University of California, Berkeley, Berkeley, California 94720, USA
3Department of Chemical Engineering, University of California, Berkeley, Berkeley, California 94720, USA
4Aerosol Dynamics Inc., Berkeley, California 94710, USA
5Department of Chemistry, Aarhus University, 8000 Aarhus C, Denmark
6Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
7National Exposure Research Laboratory, Exposure Methods and Measurements Division, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA
8Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
9School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
10Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
11Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
12Dept. of Chemistry and Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, Boulder, Colorado 80309, USA
13Department of Applied Physics, University of São Paulo, SP, Brazil
14Instituto Nacional de Pesquisas da Amazonia, Manaus, AM, Brazil
15Universidade do Estado do Amazonas, Manaus, AM, Brazil
16Instituto Nacional de Pesquisas Espiacais, São José dos Campos, SP, Brazil
17Instituto Nacional de Pesquisas Espiacais, Cachoeira Paulista, SP, Brazil
anow at: Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia 24061, USA
bnow at: Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, CA, USA
cnow at: Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, California 94720, USA
dnow at: Department of Chemistry, Colby College, Waterville, Maine 04901, USA

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Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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