Atmospheric isoprene ozonolysis: impacts of stabilised Criegee intermediate reactions with SO<sub>2</sub>, H<sub>2</sub>O and dimethyl sulfide
Isoprene is the dominant global biogenic volatile organic compound (VOC) emission. Reactions of isoprene with ozone are known to form stabilised Criegee intermediates (SCIs), which have recently been shown to be potentially important oxidants for SO<sub>2</sub> and NO<sub>2</sub...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2015-08-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/15/9521/2015/acp-15-9521-2015.pdf |
| _version_ | 1811342480865492992 |
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| author | M. J. Newland A. R. Rickard L. Vereecken A. Muñoz M. Ródenas W. J. Bloss |
| author_facet | M. J. Newland A. R. Rickard L. Vereecken A. Muñoz M. Ródenas W. J. Bloss |
| author_sort | M. J. Newland |
| collection | DOAJ |
| description | Isoprene is the dominant global biogenic volatile organic compound (VOC)
emission. Reactions of isoprene with ozone are known to form stabilised
Criegee intermediates (SCIs), which have recently been shown to be
potentially important oxidants for SO<sub>2</sub> and NO<sub>2</sub> in the atmosphere;
however the significance of this chemistry for SO<sub>2</sub> processing
(affecting sulfate aerosol) and NO<sub>2</sub> processing (affecting NO<sub><i>x</i></sub>
levels) depends critically upon the fate of the SCIs with respect to reaction
with water and decomposition. Here, we have investigated the removal of
SO<sub>2</sub> in the presence of isoprene and ozone, as a function of humidity,
under atmospheric boundary layer conditions. The SO<sub>2</sub> removal displays a
clear dependence on relative humidity, confirming a significant reaction for
isoprene-derived SCIs with H<sub>2</sub>O. Under excess SO<sub>2</sub> conditions, the
total isoprene ozonolysis SCI yield was calculated to be 0.56 (±0.03). The observed SO<sub>2</sub> removal kinetics are consistent with a relative
rate constant, <i>k</i>(SCI + H<sub>2</sub>O) / <i>k</i>(SCI + SO<sub>2</sub>), of 3.1 (±0.5) × 10<sup>−5</sup>
for isoprene-derived SCIs. The relative rate constant
for <i>k</i>(SCI decomposition) / <i>k</i>(SCI+SO<sub>2</sub>) is 3.0
(±3.2) × 10<sup>11</sup> cm<sup>−3</sup>. Uncertainties are ±2σ and represent
combined systematic and precision components. These kinetic parameters are
based on the simplification that a single SCI species is formed in isoprene
ozonolysis, an approximation which describes the results well across the
full range of experimental conditions. Our data indicate that
isoprene-derived SCIs are unlikely to make a substantial contribution to
gas-phase SO<sub>2</sub> oxidation in the troposphere. We also present results
from an analogous set of experiments, which show a clear dependence of
SO<sub>2</sub> removal in the isoprene–ozone system as a function of dimethyl
sulfide concentration. We propose that this behaviour arises from a rapid
reaction between isoprene-derived SCIs and dimethyl sulfide (DMS); the observed SO<sub>2</sub> removal
kinetics are consistent with a relative rate constant, <i>k</i>(SCI + DMS) / <i>k</i>(SCI + SO<sub>2</sub>), of 3.5 (±1.8). This result suggests that SCIs may
contribute to the oxidation of DMS in the atmosphere and that this process
could therefore influence new particle formation in regions impacted by
emissions of unsaturated hydrocarbons and DMS. |
| first_indexed | 2024-04-13T19:11:49Z |
| format | Article |
| id | doaj.art-d236aad363534a2a8cbc52146c81a4e3 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-04-13T19:11:49Z |
| publishDate | 2015-08-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-d236aad363534a2a8cbc52146c81a4e32022-12-22T02:33:50ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242015-08-0115169521953610.5194/acp-15-9521-2015Atmospheric isoprene ozonolysis: impacts of stabilised Criegee intermediate reactions with SO<sub>2</sub>, H<sub>2</sub>O and dimethyl sulfideM. J. Newland0A. R. Rickard1L. Vereecken2A. Muñoz3M. Ródenas4W. J. Bloss5University of Birmingham, School of Geography, Earth and Environmental Sciences, Birmingham, UKNational Centre for Atmospheric Science (NCAS), University of York, York, UKMax Planck Institute for Chemistry, Atmospheric Sciences, J.-J.-Becher-Weg 27, Mainz, GermanyInstituto Universitario CEAM-UMH, EUPHORE Laboratories, Avda/Charles R. Darwin, Parque Tecnologico, Valencia, SpainInstituto Universitario CEAM-UMH, EUPHORE Laboratories, Avda/Charles R. Darwin, Parque Tecnologico, Valencia, SpainUniversity of Birmingham, School of Geography, Earth and Environmental Sciences, Birmingham, UKIsoprene is the dominant global biogenic volatile organic compound (VOC) emission. Reactions of isoprene with ozone are known to form stabilised Criegee intermediates (SCIs), which have recently been shown to be potentially important oxidants for SO<sub>2</sub> and NO<sub>2</sub> in the atmosphere; however the significance of this chemistry for SO<sub>2</sub> processing (affecting sulfate aerosol) and NO<sub>2</sub> processing (affecting NO<sub><i>x</i></sub> levels) depends critically upon the fate of the SCIs with respect to reaction with water and decomposition. Here, we have investigated the removal of SO<sub>2</sub> in the presence of isoprene and ozone, as a function of humidity, under atmospheric boundary layer conditions. The SO<sub>2</sub> removal displays a clear dependence on relative humidity, confirming a significant reaction for isoprene-derived SCIs with H<sub>2</sub>O. Under excess SO<sub>2</sub> conditions, the total isoprene ozonolysis SCI yield was calculated to be 0.56 (±0.03). The observed SO<sub>2</sub> removal kinetics are consistent with a relative rate constant, <i>k</i>(SCI + H<sub>2</sub>O) / <i>k</i>(SCI + SO<sub>2</sub>), of 3.1 (±0.5) × 10<sup>−5</sup> for isoprene-derived SCIs. The relative rate constant for <i>k</i>(SCI decomposition) / <i>k</i>(SCI+SO<sub>2</sub>) is 3.0 (±3.2) × 10<sup>11</sup> cm<sup>−3</sup>. Uncertainties are ±2σ and represent combined systematic and precision components. These kinetic parameters are based on the simplification that a single SCI species is formed in isoprene ozonolysis, an approximation which describes the results well across the full range of experimental conditions. Our data indicate that isoprene-derived SCIs are unlikely to make a substantial contribution to gas-phase SO<sub>2</sub> oxidation in the troposphere. We also present results from an analogous set of experiments, which show a clear dependence of SO<sub>2</sub> removal in the isoprene–ozone system as a function of dimethyl sulfide concentration. We propose that this behaviour arises from a rapid reaction between isoprene-derived SCIs and dimethyl sulfide (DMS); the observed SO<sub>2</sub> removal kinetics are consistent with a relative rate constant, <i>k</i>(SCI + DMS) / <i>k</i>(SCI + SO<sub>2</sub>), of 3.5 (±1.8). This result suggests that SCIs may contribute to the oxidation of DMS in the atmosphere and that this process could therefore influence new particle formation in regions impacted by emissions of unsaturated hydrocarbons and DMS.http://www.atmos-chem-phys.net/15/9521/2015/acp-15-9521-2015.pdf |
| spellingShingle | M. J. Newland A. R. Rickard L. Vereecken A. Muñoz M. Ródenas W. J. Bloss Atmospheric isoprene ozonolysis: impacts of stabilised Criegee intermediate reactions with SO<sub>2</sub>, H<sub>2</sub>O and dimethyl sulfide Atmospheric Chemistry and Physics |
| title | Atmospheric isoprene ozonolysis: impacts of stabilised Criegee intermediate reactions with SO<sub>2</sub>, H<sub>2</sub>O and dimethyl sulfide |
| title_full | Atmospheric isoprene ozonolysis: impacts of stabilised Criegee intermediate reactions with SO<sub>2</sub>, H<sub>2</sub>O and dimethyl sulfide |
| title_fullStr | Atmospheric isoprene ozonolysis: impacts of stabilised Criegee intermediate reactions with SO<sub>2</sub>, H<sub>2</sub>O and dimethyl sulfide |
| title_full_unstemmed | Atmospheric isoprene ozonolysis: impacts of stabilised Criegee intermediate reactions with SO<sub>2</sub>, H<sub>2</sub>O and dimethyl sulfide |
| title_short | Atmospheric isoprene ozonolysis: impacts of stabilised Criegee intermediate reactions with SO<sub>2</sub>, H<sub>2</sub>O and dimethyl sulfide |
| title_sort | atmospheric isoprene ozonolysis impacts of stabilised criegee intermediate reactions with so sub 2 sub h sub 2 sub o and dimethyl sulfide |
| url | http://www.atmos-chem-phys.net/15/9521/2015/acp-15-9521-2015.pdf |
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