Contributions of biomass-burning, urban, and biogenic emissions to the concentrations and light-absorbing properties of particulate matter in central Amazonia during the dry season

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dc.contributor.authorde Sa, Suzane S.en
dc.contributor.authorRizzo, Luciana V.en
dc.contributor.authorPalm, Brett B.en
dc.contributor.authorCampuzano-Jost, Pedroen
dc.contributor.authorDay, Douglas A.en
dc.contributor.authorYee, Lindsay D.en
dc.contributor.authorWernis, Rebecca A.en
dc.contributor.authorIsaacman-VanWertz, Gabrielen
dc.contributor.authorBrito, Joelen
dc.contributor.authorCarbone, Samaraen
dc.contributor.authorLiu, Yingjun J.en
dc.contributor.authorSedlacek, Arthuren
dc.contributor.authorSpringston, Stephen R.en
dc.contributor.authorGoldstein, Allen H.en
dc.contributor.authorBarbosa, Henrique M. J.en
dc.contributor.authorAlexander, M. Lizabethen
dc.contributor.authorArtaxo, Pauloen
dc.contributor.authorJimenez, Jose L.en
dc.contributor.authorMartin, Scot T.en
dc.contributor.departmentCivil and Environmental Engineeringen
dc.date.accessioned2019-11-21T14:35:32Zen
dc.date.available2019-11-21T14:35:32Zen
dc.date.issued2019-06-18en
dc.description.abstractUrbanization and deforestation have important impacts on atmospheric particulate matter (PM) over Amazonia. This study presents observations and analysis of PM1 concentration, composition, and optical properties in central Amazonia during the dry season, focusing on the anthropogenic impacts. The primary study site was located 70 km downwind of Manaus, a city of over 2 million people in Brazil, as part of the GoAmazon2014/5 experiment. A high-resolution time-of-flight aerosol mass spectrometer (AMS) provided data on PM1 composition, and aethalometer measurements were used to derive the absorption coefficient b(abs,BrC) of brown carbon (BrC) at 370 nm. Non-refractory PM1 mass concentrations averaged 12.2 mu g m(-3) at the primary study site, dominated by organics (83 %), followed by sulfate (11 %). A decrease in b(abs,BrC) was observed as the mass concentration of nitrogen-containing organic compounds decreased and the organic PM1 O : C ratio increased, suggesting atmospheric bleaching of the BrC components. The organic PM1 was separated into six different classes by positive-matrix factorization (PMF), and the mass absorption efficiency E-abs associated with each factor was estimated through multivariate linear regression of b(abs,BrC) on the factor loadings. The largest E-abs values were associated with urban (2.04 +/- 0.14 m(2) g(-1)) and biomass-burning (0.82 +/- 0.04 to 1.50 +/- 0.07 m(2)g(-1)) sources. Together, these sources contributed at least 80 % of b(abs,BrC) while accounting for 30 % to 40 % of the organic PM1 mass concentration. In addition, a comparison of organic PM1 composition between wet and dry seasons revealed that only part of the 9-fold increase in mass concentration between the seasons can be attributed to biomass burning. Biomass-burning factor loadings increased by 30-fold, elevating its relative contribution to organic PM1 from about 10 % in the wet season to 30 % in the dry season. However, most of the PM1 mass (> 60 %) in both seasons was accounted for by biogenic secondary organic sources, which in turn showed an 8-fold seasonal increase in factor loadings. A combination of decreased wet deposition and increased emissions and oxidant concentrations, as well as a positive feedback on larger mass concentrations are thought to play a role in the observed increases. Furthermore, fuzzy c-means clustering identified three clusters, namely "baseline", "event", and "urban" to represent different pollution influences during the dry season. The baseline cluster, representing the dry season background, was associated with a mean mass concentration of 9 +/- 3 mu g m(-3). This concentration increased on average by 3 mu g m(-3) for both the urban and the event clusters. The event cluster, representing an increased influence of biomass burning and long-range transport of African volcanic emissions, was characterized by remarkably high sulfate concentrations. The urban cluster, representing the influence of Manaus emissions on top of the baseline, was characterized by an organic PM1 composition that differed from the other two clusters. The differences discussed suggest a shift in oxidation pathways as well as an accelerated oxidation cycle due to urban emissions, in agreement with findings for the wet season.en
dc.description.notesThis research has been supported by the Atmospheric Radiation Measurement (ARM) Climate Research Facility, a user facility of the United States Department of Energy (DOE, DE-SC0006680), Office of Science, sponsored by the Office of Biological and Environmental Research, and support from the Atmospheric System Research (ASR, DE-SC0011115, DE-SC0011105) program of that office. Additional funding was provided by the Amazonas State Research Foundation (FAPEAM 062.00568/2014 and FA-PEAM 134/2016), the Sao Paulo State Research Foundation (grant nos. FAPESP 2013/05014-0, FAPESP 2017/170470, FAPESP 2013/50510-5, and FAPESP 2013/10156-8), the US National Science Foundation (grant nos. 1106400 and 1332998), and the Brazilian Scientific Mobility Program (CsF/CAPES). Brett B. Palm, Pedro Campuzano-Jost, Douglas A. Day, and Jose L. Jimenez were supported by DOE (BER/ASR (grant no. DE-SC0016559) and NSF (grant no. AGS-1822664)).en
dc.description.sponsorshipAtmospheric Radiation Measurement (ARM) Climate Research Facility of United States Department of Energy (DOE), Office of Science - Office of Biological and Environmental ResearchUnited States Department of Energy (DOE) [DE-SC0006680]; Sao Paulo State Research FoundationFundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [FAPESP 2013/05014-0, FAPESP 2017/170470, FAPESP 2013/50510-5, FAPESP 2013/10156-8]; US National Science FoundationNational Science Foundation (NSF) [1106400, 1332998]; Brazilian Scientific Mobility Program (CsF/CAPES); DOE (BER/ASR)United States Department of Energy (DOE) [DE-SC0016559]; NSFNational Science Foundation (NSF) [AGS-1822664]; Amazonas State Research Foundation [FAPEAM 062.00568/2014, FA-PEAM 134/2016]; Atmospheric System Research (ASR) [DE-SC0011115, DE-SC0011105]en
dc.format.mimetypeapplication/pdfen
dc.identifier.doihttps://doi.org/10.5194/acp-19-7973-2019en
dc.identifier.eissn1680-7324en
dc.identifier.issn1680-7316en
dc.identifier.issue12en
dc.identifier.urihttp://hdl.handle.net/10919/95824en
dc.identifier.volume19en
dc.language.isoenen
dc.publisherEuropean Geophysical Unionen
dc.rightsCreative Commons Attribution 4.0 Internationalen
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/en
dc.titleContributions of biomass-burning, urban, and biogenic emissions to the concentrations and light-absorbing properties of particulate matter in central Amazonia during the dry seasonen
dc.title.serialAtmospheric Chemistry and Physicsen
dc.typeArticle - Refereeden
dc.type.dcmitypeTexten
dc.type.dcmitypeStillImageen

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