Submicron particle mass concentrations and sources in the Amazonian wet season...

The core information for this publication's citation.: 
Chen, Q., D. K. Farmer, L. V. Rizzo, T. Pauliquevis, M. Kuwata, T. Karl, A. Guenther, J. D. Allan, H. Coe, M. O. Andreae, U. Pöschl, J. Jimenez-Palacios, P. Artaxo, and S. Martin (2015), Submicron particle mass concentrations and sources in the Amazonian wet season (AMAZE-08), Atmos. Chem. Phys., 15, 3687-3701, doi:10.5194/acp-15-3687-2015.
Abstract: 

Real-time mass spectra of the non-refractory species in submicron aerosol particles were recorded in a tropical rainforest in the central Amazon Basin during the wet season from February to March 2008, as a part of the Amazonian Aerosol Characterization Experiment (AMAZE08). Organic material accounted on average for more than 80 % of the non-refractory submicron particle mass concentrations during the period of measurements. There was insufficient ammonium to neutralize sulfate. In this acidic, isoprene-rich, HO2 -dominant environment, positive-matrix factorization of the time series of particle mass spectra identified four statistical factors to account for the 99 % of the variance in the signal intensities of the organic constituents. The first factor was identified as associated with regional and local pollution and labeled “HOA” for its hydrocarbon-like characteristics. A second factor was associated with longrange transport and labeled “OOA-1” for its oxygenated characteristics. A third factor, labeled “OOA-2,” was implicated as associated with the reactive uptake of isoprene oxidation products, especially of epoxydiols to acidic haze, fog, or cloud droplets. A fourth factor, labeled “OOA-3,” was consistent with an association with the fresh production of secondary organic material (SOM) by the mechanism of gasphase oxidation of biogenic volatile organic precursors followed by gas-to-particle conversion of the oxidation products. The suffixes 1, 2, and 3 on the OOA labels signify ordinal ranking with respect to the extent of oxidation represented by the factor. The process of aqueous-phase oxidation of water-soluble products of gas-phase photochemistry might also have been associated to some extent with the OOA-2 factor. The campaign-average factor loadings had a ratio of 1.4 : 1 for OOA-2 : OOA-3, suggesting the comparable importance of particle-phase compared to gas-phase pathways for the production of SOM during the study period.

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Research Program: 
Tropospheric Composition Program (TCP)
Mission: 
AMAZE-08