edu.ucar.opensky::articles:15222 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T14:59:56.389400 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7qj7j9g Mass spectral characterization of submicron biogenic organic particles in the Amazon Basin 2009-10-28T00:00:00Z publication https://n2t.org/ark:/85065/d7qj7j9g https://doi.org/10.1029/2009GL039880 Chen, Q. author Farmer, D. author Schneider, J. author Zorn, S. author Heald, C. author Karl, Thomas author Guenther, Alex B. author Allan, J. author Robinson, N. author Coe, H. author Kimmel, J. author Pauliquevis, T. author Borrmann, S. author Poschl, U. author Andreae, M. author Artaxo, P. author Jimenez, J. author Martin, S. author UCAR/NCAR - Library publisher Submicron atmospheric particles in the Amazon Basin were characterized by a high-resolution aerosol mass spectrometer during the wet season of 2008. Patterns in the mass spectra closely resembled those of secondary-organic-aerosol (SOA) particles formed in environmental chambers from biogenic precursor gases. In contrast, mass spectral indicators of primary biological aerosol particles (PBAPs) were insignificant, suggesting that PBAPs contributed negligibly to the submicron fraction of particles during the period of study. For 40% of the measurement periods, the mass spectra indicate that in-Basin biogenic SOA production was the dominant source of the submicron mass fraction, contrasted to other periods (30%) during which out-of-Basin organic-carbon sources were significant on top of the baseline in-Basin processes. The in-Basin periods had an average organic-particle loading of 0.6 ⁻μg m⁻³ and an average elemental oxygen-to-carbon (O:C) ratio of 0.42, compared to 0.9 ⁻μg m⁻³ and 0.49, respectively, during periods of out-of-Basin influence. On the basis of the data, we conclude that most of the organic material composing submicron particles over the Basin derived from biogenic SOA production, a finding that is consistent with microscopy observations made in a concurrent study. This source was augmented during some periods by aged organic material delivered by long-range transport. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication An edited version of this paper was published by AGU. Copyright 2009 American Geophysical Union. None eng geoscientificInformation