0000000000345254

AUTHOR

Ralf Tillmann

showing 3 related works from this author

Volatility of secondary organic aerosol during OH radical induced ageing

2011

The aim of this study was to investigate oxidation of SOA formed from ozonolysis of <i>α</i>-pinene and limonene by hydroxyl radicals. This paper focuses on changes of particle volatility, using a Volatility Tandem DMA (VTDMA) set-up, in order to explain and elucidate the mechanism behind atmospheric ageing of the organic aerosol. The experiments were conducted at the AIDA chamber facility of Karlsruhe Institute of Technology (KIT) in Karlsruhe and at the SAPHIR chamber of Forchungzentrum Jülich (FZJ) in Jülich. A fresh SOA was produced from ozonolysis of <i>α</i>-pinene or limonene and then aged by enhanced OH exposure. As an OH radical source in…

High concentrationAtmospheric ScienceLimoneneOzonolysisRadicalPhotochemistrylcsh:QC1-999AerosolJlcsh:Chemistrychemistry.chemical_compoundlcsh:QD1-999chemistryAgeingddc:550Organic chemistryVolatility (chemistry)Chemical compositionlcsh:Physics
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Aging of biogenic secondary organic aerosol via gas-phase OH radical reactions

2012

The Multiple Chamber Aerosol Chemical Aging Study (MUCHACHAS) tested the hypothesis that hydroxyl radical (OH) aging significantly increases the concentration of first-generation biogenic secondary organic aerosol (SOA). OH is the dominant atmospheric oxidant, and MUCHACHAS employed environmental chambers of very different designs, using multiple OH sources to explore a range of chemical conditions and potential sources of systematic error. We isolated the effect of OH aging, confirming our hypothesis while observing corresponding changes in SOA properties. The mass increases are consistent with an existing gap between global SOA sources and those predicted in models, and can be described b…

OzoneFree Radicals010504 meteorology & atmospheric sciencesUltraviolet Rayschemistry.chemical_element010501 environmental sciencesMass spectrometrybehavioral disciplines and activities01 natural sciencesOxygenMass SpectrometryAtmospherechemistry.chemical_compoundOzoneOrganic Chemicals0105 earth and related environmental sciencesAerosolsMultidisciplinaryOzonolysisAtmosphereHydroxyl RadicalReproducibility of ResultsAerosolOxygenModels ChemicalchemistryAtmospheric chemistryEnvironmental chemistryPhysical SciencesSolventsHydroxyl radicalProceedings of the National Academy of Sciences of the United States of America
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Suppression of new particle formation from monoterpene oxidation by NO<sub>x</sub>

2014

Abstract. The impact of nitrogen oxides (NOx = NO + NO2) on new particle formation (NPF) and on photochemical ozone production from real plant volatile organic compound (BVOC) emissions was studied in a laboratory setup. At high NOx conditions ([BVOC] / [NOx] < 7, [NOx] > 23 ppb) new particle formation was suppressed. Instead, photochemical ozone formation was observed resulting in higher hydroxyl radical (OH) and lower nitrogen monoxide (NO) concentrations. When [NO] was reduced back to levels below 1 ppb by OH reactions, NPF was observed. Adding high amounts of NOx caused NPF to be slowed by orders of magnitude compared to analogous experiments at low NOx conditions ([NOx] ~300 ppt)…

chemistry.chemical_classificationAtmospheric Science010504 meteorology & atmospheric sciencesMonoterpeneRadicalPhotodissociation010501 environmental sciencesRate-determining stepPhotochemistry01 natural sciencesOrganic compoundchemistry.chemical_compoundchemistry13. Climate actionParticleHydroxyl radicalNOx0105 earth and related environmental sciencesAtmospheric Chemistry and Physics
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