Physical-chemical properties of biogenic secondary organic aerosols in the Amazon Forest

Abstract

This Pos Doc Research Project focus on the study of biogenic secondary organic aerosol in natural regions in Amazonia, in the context of the GoAmazon Project. The forest naturally emits a large number of gaseous compounds; they are called the volatile organic compounds (VOCs). They are emitted through processes that are not totally understood. Part of those gaseous compounds are converted into aerosol particles, which affect the biogeochemical cycles, the radiation balance, the mechanisms involving cloud formation and evolution, among few other important effects. In this proposal we will study the aerosol life-cycle in Amazonia with emphasis on the natural organic component and its impacts in the ecosystem. To achieve these objectives physical and chemical aerosol properties will be investigated, such as the chemical composition with aerosol mass spectrometry (AMS), nanoparticle size distribution (using the SMPS - Scanning Mobility Particle Sizer), optical properties with measurements of scattering and absorption (using nephelometers and aethalometers), VOCs concentration and fluxes with the PTR-MS (Proton Transfer Reaction Mass Spectrometry), the concentration of trace gases O2, CO2, SO2, CO, NOx and meteorological parameters. The measurements will take place in the three sites of the GoAmazon project: upstream of Manaus wind plume (ATTO, ZF2 and Embrapa) and in the Golfstream G1 airplane, United States Department of Energy. The measurements in the ZF2 will be performed during at least one year, in order to obtain a seasonal variability and the airplane measurements will provide the distribution in the large scale. The AMS datasets will be analyzed using the Positive Matrix Factorization (PMF), and receptor models will be used to connect the organic aerosol and the optical properties, gases and meteorological parameters. Innovative chemical characterization technique will be used in order to fully characterize the organic aerosol component. This proposal aims to elucidate critical mechanisms of natural biogenic aerosol particle formation and their impacts in the atmospheric radiation balance through measurement of optical properties. This study will complement the GoAmazon Project by investigating essential mechanisms in the formation of secondary organic aerosol in Central Amazonia. (AU)