A5012499684- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Air Quality and Health Impacts
- Catalytic Processes in Materials Science
- Atmospheric aerosols and clouds
- Air Quality Monitoring and Forecasting
- Spectroscopy and Laser Applications
- Catalysis and Oxidation Reactions
- Industrial Gas Emission Control
- Atmospheric and Environmental Gas Dynamics
- Free Radicals and Antioxidants
- Nuclear Physics and Applications
- Nuclear reactor physics and engineering
- Nuclear Materials and Properties
- Vehicle emissions and performance
- Oxidative Organic Chemistry Reactions
- Analytical Chemistry and Chromatography
- Chemical Thermodynamics and Molecular Structure
- Water Quality Monitoring and Analysis
- Asymmetric Hydrogenation and Catalysis
- Catalysis for Biomass Conversion
- Methane Hydrates and Related Phenomena
- Advanced Chemical Sensor Technologies
- Radical Photochemical Reactions
- Chemical Synthesis and Reactions
Leibniz Institute for Tropospheric Research
2016-2025
Leibniz Association
2015
Leibniz Institute for Neurobiology
2004-2014
University of Antwerp
2007
University of Helsinki
2005
Martin Luther University Halle-Wittenberg
1994
Merseburg University of Applied Sciences
1991-1993
Zentralinstitut für die Kassenärztliche Versorgung in der Bundesrepublik Deutschland
1990
Little Things Do Matter Gas-phase sulfuric acid is important during atmospheric particle formation, but the mechanisms by which it forms new particles are unclear. Laboratory studies of binary nucleation with water produce at rates that many orders magnitude too small to explain concentration found in atmosphere. Sipilä et al. (p. 1243 ) now show gas-phase does, fact, undergo presence a rate fast enough account for observed abundance These particles, contain 1 2 molecules each, were not...
Significance Extremely low volatility organic compounds (ELVOC) are suggested to promote aerosol particle formation and cloud condensation nuclei (CCN) production in the atmosphere. We show that capability of biogenic VOC (BVOC) produce ELVOC depends strongly on their chemical structure relative oxidant levels. BVOC with an endocyclic double bond, representative emissions from, e.g., boreal forests, efficiently from ozonolysis. Compounds exocyclic bonds or acyclic including isoprene,...
The formation of organosulfates from the gas-phase ozonolysis β-pinene in presence neutral or acidic sulfate particles was investigated a series indoor aerosol chamber experiments. were analyzed using high-performance liquid chromatography (LC) coupled to electrospray ionization−time-of-flight mass spectrometry (MS) parallel ion trap MS. Organosulfates only found secondary organic seed particles. One detected also occurred ambient samples that collected at forest site northeastern Bavaria,...
Abstract Gas‐phase oxidation routes of biogenic emissions, mainly isoprene and monoterpenes, in the atmosphere are still subject intensive research with special attention being paid to formation aerosol constituents. This laboratory study shows that most abundant monoterpenes (limonene α‐pinene) form highly oxidized RO 2 radicals up 12 O atoms, along related closed‐shell products, within a few seconds after initial attack ozone or OH radicals. The overall process, an intramolecular ROO→QOOH...
Abstract Explaining the formation of secondary organic aerosol is an intriguing question in atmospheric sciences because its importance for Earth’s radiation budget and associated effects on health ecosystems. A breakthrough was recently achieved understanding from ozone reactions biogenic emissions by rapid highly oxidized multifunctional compounds via autoxidation. However, important daytime hydroxyl radical have been considered to be less this process. Here we report measurements reaction...
Abstract Hydrocarbons are emitted into the Earth's atmosphere in very large quantities by human and biogenic activities. Their atmospheric oxidation processes almost exclusively yield RO 2 radicals as reactive intermediates whose fate is not yet fully unraveled. Herein, we show that gas‐phase reactions of two produce accretion products composed carbon backbone both reactants. The rates for product formation high bearing functional groups, competing with those corresponding NO HO . This...
α-Pinene (C10H16) represents one of the most important biogenic emissions in atmosphere. Its oxidation products can significantly contribute to secondary organic aerosol (SOA) formation. Here, we report on formation mechanism C19 and C20 accretion from α-pinene oxidation, which are believed be efficient SOA precursors. Measurements have been performed a free-jet flow system. Detection RO2 radicals was carried out by recent mass spectrometric techniques using different ionization schemes....
Very recent studies have reported the existence of highly oxidized multifunctional organic compounds (HOMs) with O/C ratios greater than 0.7. Because their low vapor pressure, these are often referred as extremely low-volatile (ELVOCs), and thus, they able to contribute significantly mass in tropospheric particles. While HOMs been successfully detected gas phase, fate after uptake into particles remains unclear date. Hence, present study was designed detect related oxidation products...
Aromatic hydrocarbons contribute significantly to tropospheric ozone and secondary organic aerosols (SOA). Despite large efforts in elucidating the formation mechanism of aromatic-derived SOA, current models still substantially underestimate SOA yields when comparing field measurements. Here we present a new, up now undiscovered pathway for highly oxidized products from OH-initiated oxidation alkyl benzenes based on theoretical experimental investigations. We propose that unimolecular...
Abstract. Recent studies have recognised highly oxygenated organic molecules (HOMs) in the atmosphere as important formation of secondary aerosol (SOA). A large number focused on HOM from oxidation biogenically emitted monoterpenes. However, anthropogenic vapours has so far received much less attention. Previous identified importance aromatic volatile compounds (VOCs) for SOA formation. In this study, we investigated several compounds, benzene (C6H6), toluene (C7H8), and naphthalene (C10H8),...
Dimethyl sulfide (DMS), produced by marine organisms, represents the most abundant, biogenic sulfur emission into Earth's atmosphere. The gas-phase degradation of DMS is mainly initiated reaction with OH radical forming first CH3SCH2O2 radicals from dominant H-abstraction channel. It experimentally shown that these peroxy undergo a two-step isomerization process finally product consistent formula HOOCH2SCHO. accompanied recycling. rate-limiting step, → CH2SCH2OOH, followed O2 addition,...
Abstract. Nucleation experiments starting from the reaction of OH radicals with SO2 have been performed in IfT-LFT flow tube under atmospheric conditions at 293±0.5 K for a relative humidity 13–61%. The presence different additives (H2, CO, 1,3,5-trimethylbenzene) adjusting radical concentration and resulting levels range (4–300) ×105 molecule cm−3 did not influence nucleation process itself. number detected particles as well threshold H2SO4 needed was found to be strongly dependent on...
We investigated the formation of new particles in a laboratory study, starting from H2SO4 produced situ through reaction OH radicals with SO2. Newly formed were observed for concentrations above 7 x 10(6) per cubic centimeter. At 293 kelvin, rough estimate yielded nucleation rate 0.3 to 0.4 centimeter second approximately 10(7) (particle size >/= 3 nanometers). These findings are agreement observations atmosphere. The results demonstrate that under conditions similar atmosphere, particle...
The gas-phase reaction of ozone with C5–C8 cycloalkenes has been investigated in a free-jet flow system at atmospheric pressure and temperature 297 ± 1 K. Highly oxidized RO2 radicals bearing least 5 O atoms the molecule their subsequent products were detected most cases by means nitrate-CI-APi-TOF mass spectrometry. Starting from Criegee intermediate after splitting-off an OH-radical, formation these can be explained via autoxidation mechanism, meaning isomerization (ROO → QOOH)...
Stabilized Criegee Intermediates (sCIs) have been identified as oxidants of atmospheric trace gases such SO2, NO2, carboxylic acids or carbonyls. The sCI concentrations, and accordingly their importance for gas oxidation, are controlled by the rate most important loss processes, very likely unimolecular reactions reaction with water vapour (monomer dimer) ubiquitously present at high concentrations in troposphere. In this study, coefficients simplest sCI, formaldehyde oxide, CH2OO, its...
The performance of the novel ammonium chemical ionization time flight mass spectrometer (NH4+-CI3–TOF) utilizing NH4+ adduct ion chemistry to measure first generation oxidized product molecules (OMs) as well highly organic (HOMs) was investigated for time. gas-phase ozonolysis cyclohexene served a test system. Experiments have been carried out in TROPOS free-jet flow system at close atmospheric conditions. Product signals were simultaneously observed by NH4+-CI3-TOF and acetate pressure...
Abstract. Oxidation processes in Earth's atmosphere are tightly connected to many environmental and human health issues essential drivers for biogeochemistry. Until the recent discovery of atmospheric relevance reaction stabilized Criegee intermediates (sCIs) with SO2, oxidation were thought be dominated by a few main oxidants: ozone, hydroxyl radicals (OH), nitrate and, e.g. over oceans, halogen atoms such as chlorine. Here, we report results from laboratory experiments at 293 K pressure...
H2SO4 formation from the reaction CH2OO + SO2 has been measured as a function of water vapour concentration for close to atmospheric conditions. Second-order kinetics with regard indicates preferred dimer. The obtained kinetic parameters lead conclusion that fate is dominated by vapour. A comparison results CH3CHOO and (CH3)2COO structure dependent reactivity stabilized Criegee intermediates.
Abstract Isoprene, C 5 H 8 , inserts about half of the non-methane carbon flux biogenic origin into atmosphere. Its degradation is primarily initiated by reaction with hydroxyl radicals. Here we show experimentally formation reactive intermediates and corresponding closed-shell products from radicals isoprene for low nitric oxide hydroperoxy radical conditions. Detailed product analysis achieved mass spectrometric techniques. Quantum chemical calculations support usefulness applied...
Abstract Oxidation chemistry controls both combustion processes and the atmospheric transformation of volatile emissions. In engines, radical species undergo isomerization reactions that allow fast addition O 2 . This chain reaction, termed autoxidation, is enabled by high engine temperatures, but has recently been also identified as an important source for highly oxygenated in atmosphere, forming organic aerosol. Conventional knowledge suggests autoxidation requires suitable structural...