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In-cloud multiphase behaviour of acetone in the troposphere: Gas uptake, Henry’s law equilibrium and aqueous phase photooxidation
- Source :
- Chemosphere, Chemosphere, Elsevier, 2010, 81 (3), pp.312-320. ⟨10.1016/j.chemosphere.2010.07.032⟩, Chemosphere, 2010, 81 (3), pp.312-320. ⟨10.1016/j.chemosphere.2010.07.032⟩
- Publication Year :
- 2010
- Publisher :
- Elsevier BV, 2010.
-
Abstract
- Acetone is ubiquitous in the troposphere. Several papers have focused in the past on its gas phase reactivity and its impact on tropospheric chemistry. However, acetone is also present in atmospheric water droplets where its behaviour is still relatively unknown. In this work, we present its gas/aqueous phase transfer and its aqueous phase photooxidation. The uptake coefficient of acetone on water droplets was measured between 268 and 281 K ( γ = 0.7 × 10 −2 –1.4 × 10 −2 ), using the droplet train technique coupled to a mass spectrometer. The mass accommodation coefficient α (derived from γ ) was found in the range (1.0–3.0 ± 0.25) × 10 −2 . Henry’s law constant of acetone was directly measured between 283 and 298 K using a dynamic equilibrium system ( H (298K) = (29 ± 5) M atm −1 ), with the Van’t Hoff expression ln H ( T ) = (5100 ± 1100)/ T − (13.4 ± 3.9). A recommended value of H was suggested according to comparison with literature. The OH-oxidation of acetone in the aqueous phase was carried out at 298 K, under two different pH conditions: at pH = 2, and under unbuffered conditions. In both cases, the formation of methylglyoxal, formaldehyde, hydroxyacetone, acetic acid/acetate and formic acid/formate was observed. The formation of small amounts of four hydroperoxides was also detected, and one of them was identified as peroxyacetic acid. A drastic effect of pH was observed on the yields of formaldehyde, one hydroperoxide, and, (to a lesser extent) acetic acid/acetate. Based on the experimental observations, a chemical mechanism of OH-oxidation of acetone in the aqueous phase was proposed and discussed. Atmospheric implications of these findings were finally discussed.
- Subjects :
- Environmental Engineering
010504 meteorology & atmospheric sciences
Formic acid
Health, Toxicology and Mutagenesis
Inorganic chemistry
Formaldehyde
010501 environmental sciences
01 natural sciences
Phase Transition
Acetone
chemistry.chemical_compound
Acetic acid
[CHIM.ANAL]Chemical Sciences/Analytical chemistry
Environmental Chemistry
Formate
ComputingMilieux_MISCELLANEOUS
0105 earth and related environmental sciences
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere
Air Pollutants
Aqueous solution
Atmosphere
Hydroxyacetone
Public Health, Environmental and Occupational Health
General Medicine
General Chemistry
Photochemical Processes
Pollution
Henry's law
[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry
chemistry
13. Climate action
Oxidation-Reduction
Subjects
Details
- ISSN :
- 00456535
- Volume :
- 81
- Database :
- OpenAIRE
- Journal :
- Chemosphere
- Accession number :
- edsair.doi.dedup.....4e2efbdf635acfc783a8187f2627c4c2