Aerosol Loadings in the Future Atmosphere (ALFA) - Improving Predictive Capability of Atmospheric Aerosol Loadings through Molecular-level Understanding of the Transformation of Present-day and Future-scenario Emissions

• Applicant: Professor Dr. Alexander Vogel
• Subject Area: Atmospheric Science
• Term: since 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 410009325

Atmospheric aerosols affect human health and the radiative balance of the Earth. The sources, formation mechanisms and sinks of secondary aerosols, resulting from the transformation of organic and inorganic precursor gases, are not well understood. Hence, accurate predictability of aerosol loadings under present emissions and future scenarios is not possible.In order to gain a more accurate understanding of the process, we will develop new analytical methods that allow the measurement of individual aerosol-borne molecules in real time, and the generation of molecular fingerprints of aerosol filter samples. For this purpose, we will be adapting an ultra-high resolution (OrbitrapTM) mass spectrometer (MS) for real-time aerosol measurement. In order to investigate the chemistry of aerosols under future emission scenarios we will simulate future atmospheric aerosol formation in the SAPHIR chamber at the research centre Jülich. We will study VOC emissions of plants under stress and their interaction with SO2, NOX and NH3. The central focus of these experiments is how excess ammonia reacts with volatile organic compounds (VOCs) in the atmosphere, and whether there is an increased formation of absorbing organic nitrogen heterocycles under these conditions. The relevance of heterogeneous photochemically induced processes shall be investigated at the SAPHIR chamber at atmospheric concentrations. These studies are needed to make predictions about how changing future inorganic emissions and VOC emissions from stressed plants will have an effect on the chemical and physical properties of aerosols in the future atmosphere.In addition to the chamber measurements at Jülich, field measurements are to be made at locations where a particularly strong interaction between organic and inorganic components is to be expected, and thus the chamber experiments can be validated with regard to their atmospheric relevance.During real-time measurements with the online aerosol Orbitrap-MS, we shall in parallel collect aerosol filter samples and produce molecular fingerprints of the aerosol composition using high performance liquid chromatography / mass spectrometry. Based on laboratory studies on the oxidation of individual VOCs, we will compare the molecular fingerprints of the real samples with the laboratory experiments. An open-access "aerosolomics" database is to be created that will archive the measured characteristics of individual oxidation products and make them available online. This will allow for a top-down classification of aerosol samples that can be used to predict which VOCs and which processes are responsible for the secondary formation of atmospheric aerosol at various locations.

• DFG Programme: Independent Junior Research Groups
• Major Instrumentation: Laborcontainer ; Massenspektrometer
• Instrumentation Group: 1700 Massenspektrometer ; 9490 Sonstige Werkstatt- und Laborausrüstung, Werkzeuge