Time Resolved Infrared Spectroscopy of Formation and Processing of Secondary Organic Aerosol
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J. Ofner
Abstract
An aerosol flow reactor was coupled to an infrared absorption cell to study aerosol formation processes with high temporal resolution. The recorded infrared spectra were referenced using aerosol smog chamber experiments. Evaluation was done by studying the formation of secondary organic aerosol from α-pinene and catechol as precursors and ozone as oxidant. Three main infrared absorptions: ν(O-H), ν(C-H) and ν(C=O) were considered, and humic like properties of the secondary organic aerosol are mainly interpreted according to the formation and variations of carbonyl bands in the region between 1850 and 1600 cm−1, especially the ν(C=O) of aryl carbonyls from catechol oxidation products below 1700 cm−1. The relative intensities of two major ν(C=O) stretching vibrations at 1690 cm−1 and 1755 cm−1 were observed to depend strongly on the available ozone concentration. At high precursor/ozone ratios (2:1 or 1:1) the vibration at 1690 cm−1 predominates, indicating aryl carbonyl vibrations. With increasing ozone concentrations this vibration is replaced by the higher carbonyl vibration at 1755 cm−1 indicating unsaturated carbonyl-containing compounds. This is a strong hint at ring opening processes leading to unsaturated aliphatic compounds in the resulting particle. Aryl carbonyls and aromatic or olefinic ν(C=C) at 1620 cm−1 in aged particles remain visible, as aerosol smog chamber studies exhibit – thus a strong hint at humic like properties of the SOA from the spectroscopic point of view.
© by Oldenbourg Wissenschaftsverlag, Bayreuth, Germany
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- Pressure Dependence of Iso-Propyl Nitrate Formation in the i-C3H7O2 + NO Reaction
- Photolysis of Trichloronitromethane (Chloropicrin) under Atmospheric Conditions
- The Gas-phase Ozonolysis of 1-Penten-3-ol, (Z)-2-Penten-1-ol and 1-Penten-3-one: Kinetics, Products and Secondary Organic Aerosol Formation
- Theoretical Study of the HOCH2OO• + HO2• Reaction: Detailed Molecular Mechanisms of the Three Reaction Channels
- Studies of the Formation and Growth of Aerosol from Molecular Iodine Precursor
- Heterogeneous Chemistry of Cl2O and HOCl on Frozen Natural Sea Salt, Recrystallized Sea Salt, KCl and NaCl Solutions at 200 and 215 K
- Atmospheric Heterogeneous Reactions of Benzo(a)pyrene
- Time Resolved Infrared Spectroscopy of Formation and Processing of Secondary Organic Aerosol
- Probing the Equilibrium Size and Hydrogen Bonding Structure in Aqueous Aerosol Droplets
- Interaction of NO2 with Soot: Oxidation and Gasification at Temperatures Between 300 and 670 K
- Uptake of Organic Acids on Ice Surfaces: Evidence for Surface Modification and Hydrate Formation
- Aqueous Phase Reactivity of Nitrate Radicals (NO3) Toward Dicarboxylic Acids
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Artikel in diesem Heft
- Physico-Chemical Aspects of Global Atmospheric Change. Dedicated to Reinhard Zellner on the occasion of his 65th birthday
- The Quest for the Hydroxyl-Peroxy Radical
- Sources and Cycling of Tropospheric Hydroxyl Radicals – An Overview
- Kinetics and Products of the Reaction O2(1Σg+) with N2O
- An Experimental and Theoretical Study of the Reaction Between NH(X3Σ−) + SO(X3Σ−)
- Pressure Dependence of Iso-Propyl Nitrate Formation in the i-C3H7O2 + NO Reaction
- Photolysis of Trichloronitromethane (Chloropicrin) under Atmospheric Conditions
- The Gas-phase Ozonolysis of 1-Penten-3-ol, (Z)-2-Penten-1-ol and 1-Penten-3-one: Kinetics, Products and Secondary Organic Aerosol Formation
- Theoretical Study of the HOCH2OO• + HO2• Reaction: Detailed Molecular Mechanisms of the Three Reaction Channels
- Studies of the Formation and Growth of Aerosol from Molecular Iodine Precursor
- Heterogeneous Chemistry of Cl2O and HOCl on Frozen Natural Sea Salt, Recrystallized Sea Salt, KCl and NaCl Solutions at 200 and 215 K
- Atmospheric Heterogeneous Reactions of Benzo(a)pyrene
- Time Resolved Infrared Spectroscopy of Formation and Processing of Secondary Organic Aerosol
- Probing the Equilibrium Size and Hydrogen Bonding Structure in Aqueous Aerosol Droplets
- Interaction of NO2 with Soot: Oxidation and Gasification at Temperatures Between 300 and 670 K
- Uptake of Organic Acids on Ice Surfaces: Evidence for Surface Modification and Hydrate Formation
- Aqueous Phase Reactivity of Nitrate Radicals (NO3) Toward Dicarboxylic Acids
- Temperature and Ionic Strength Dependence of NO3-radical Reactions with Substituted Phenols in Aqueous Solution
