Description: Das Projekt "Field and laboratory studies of aerosol formation from halogenated precursor gases" wird vom Umweltbundesamt gefördert und von Technische Universität Berlin, Institut für Technischen Umweltschutz durchgeführt. This project was part of the HaloProc research unit on natural halogenation processes, and explored the impact of reactive halogen species on aerosol formation in field and laboratory experiments. Field studies were focused on the Lake King salt lake area in Western Australia. New particle formation events were frequently observed and characterized by measuring the temporal evolution of the submicron aerosol size distributions, and collecting aerosol samples for subsequent chemical analysis. 9 out of 11 measurement days in 2013 showed secondary aerosol formation with particle growth rates from 2.9 to 25.4 nm h^-1. Raman spectroscopy and ultrahigh resolution mass spectrometry revealed a contribution of organohalogen compounds (mostly organochlorine) to the secondary organic aerosol, however, organosulfate and organonitrate formation seemed to play a larger role in the studied environment. Nevertheless, a new experimental approach that made use of a mobile Teflon chamber set up above the salt crust and the organic-rich mud layer of various salt lakes directly linked new particle formation to the hypersaline environment of Western Australia. For more detailed process studies, these field results provided realistic scenarios and constraints for simulation experiments in the laboratory. Salt lake conditions were successfully simulated in aerosol chamber experiments and showed secondary aerosol formation in the presence of light and organic precursor compounds. The particle formation dynamics and the chemical speciation of aerosol samples, which were collected from the chamber experiments and analyzed by Raman spectroscopy and mass spectrometry, indicated a coupling of aqueous phase chemistry and secondary aerosol formation. In particular, the Fe(II) concentrations of the simulated salt lakes were a key control for the intensity of new particle formation. In saline environments with low pH values and high solar radiation, Fe(II) might be converted to Fe(III) in the presence of organic matter in a Fenton-like reaction, which can act as a major source for highly reactive OH radicals in the aqueous phase. On the one hand, this expands the potential oxidation pathways for organic compounds, which led to a larger chemical diversity. On the other hand, Fe(II)-controlled aqueous phase chemistry competes with secondary aerosol formation in the gas phase, which led to reduced particle formation in our experiments. While it is premature to fully incorporate these findings in chemistry box models, additional laboratory studies provided experimental data that will guide the development of model parameterizations, e.g., for the organic aerosol yield from the oxidation of organic compounds by chlorine and bromine, or for reactive bromine loss due to uptake in secondary organic aerosol. In conclusion, this project bridged gaps between field studies of halogen-influenced new particle formation in the real world and laboratory experiments within the HaloProc research u
Types:
SupportProgram
Origin: /Bund/UBA/UFORDAT
Tags: Brom ? Seen ? Polytetrafluorethylen ? Berlin ? Beleuchtung ? Bromverbindung ? Fischer-Tropsch-Verfahren ? Halogen ? Halogenkohlenwasserstoffe ? Skigebiet ? Solarstrahlung ? Salz ? Organische Chlorverbindungen ? Namibia ? Vorläufersubstanz ? Abscheider ? Aerosol ? Chemische Analyse ? Ernteertrag ? Gewässersediment ? Halogenverbindung ? Lagerstätte ? Licht ? Massenspektrometrie ? Spektralanalyse ? Organisches Material ? Szenario ? Organische Verbindung ? Gasförmiger Stoff ? Australien ? Oxidation ? Bildung ? Größenverteilung ? Redoxpotential ? Simulation ? Studie ? Umwelttechnik ? Wirkungsforschung ? Laborversuch ? Datenmodell ? Chemikalien ? Bodenprozess ? Daten ? Evolution ? Feldstudie ? Atmosphäre ? Forschung ? Forschungseinrichtung ? Bauelement ? Umwelt ? Probenahme ? Kontrolle ? Partikel ? Freilandversuch ? neu ? Art [Spezies] ? Bram-Verfahren ? Aerosolentstehung ? Salzbildung ? Teil ? Diversität ? Ergebnis ? Verhältnis ? Ertragsminderung ? Vorgabe ? Wert ? Experiment ? bewerten ? Adsox-Verfahren ? Forschungsgebiet ? Pfad ? Quellen ?
Region: Berlin
Bounding box: 10.44987° .. 10.44987° x 54.03573° .. 54.03573°
License: cc-by-nc-nd/4.0
Language: Deutsch
Time ranges: 2011-01-01 - 2015-12-31
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