| NSF Org: |
AGS Division of Atmospheric and Geospace Sciences |
| Recipient: |
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| Initial Amendment Date: | April 1, 2014 |
| Latest Amendment Date: | April 1, 2014 |
| Award Number: | 1343077 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Sylvia Edgerton
sedgerto@nsf.gov (703)292-8522 AGS Division of Atmospheric and Geospace Sciences GEO Directorate for Geosciences |
| Start Date: | April 1, 2014 |
| End Date: | September 30, 2018 (Estimated) |
| Total Intended Award Amount: | $448,302.00 |
| Total Awarded Amount to Date: | $448,302.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
4333 BROOKLYN AVE NE SEATTLE WA US 98195-1016 (206)543-4043 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
WA US 98105-1016 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | Atmospheric Chemistry |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
This research will test the hypothesis that halogen-containing oxidants (such as HOBr) play a significant role in sulfate aerosol formation in the marine boundary layer. Because HOBr and HOCl transfer unique isotopic signatures of oxygen to their oxidation products, the oxygen isotopic composition of the measured sulfate reflects the relative importance of the different mechanisms of oxidation. Measurements of Delta(17)Oxygen in sulfate, a value dependent only on the oxidation pathway of SO2 to sulfate, will be made on aerosol filter samples previously collected from nearly every major ocean basin. The global chemical transport model GEOS-Chem will be run for the days that the filter samples were collected. The modeled data for Delta(17)Oxygen will be compared with observations to provide constraints on the relative importance of hypohalous acid (HOX) in sulfate formation at each location.
The results of this effort are important for understanding sulfate formation in the remote marine boundary layer. Sulfate is a major component of atmospheric aerosol and is especially important in the formation of new aerosol. This research is highly relevant for gaining a better understanding of cloud-aerosol chemistry and climate change.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
INTELLECTUAL MERIT
Reactive halogens have long been recognized for their importance in the stratosphere due to their influence on stratospheric ozone. In contrast, reactive halogen chemistry in the lower atmosphere is not well-understood, but is increasingly thought to provide a critical role in the oxidative capacity of the atmosphere. This project provided the first observational constraint for interactions between the tropospheric sulfur and reactive halogen budgets. We found that reactive halogens play a major role in the formation of sulfate aerosol in the remote marine boundary layer, with implications for our understanding of sulfate aerosol formation in the pristine, preindustrial atmosphere. Additionally, we found that sulfur oxidation by reactive halogens is a major sink for reactive halogens in the troposphere. Inclusion of this chemistry in a global model largely reconciled the model’s overestimate of bromine monoxide in the troposphere.
BROADER IMPACTS
This research has dramatically improved our understanding of reactive halogen chemistry in the troposphere. This will ultimately improve our ability to predict the future atmospheric oxidant abundances with implications for the concentrations pollutants and greenhouse gases. This project provided training for one graduate student and two undergraduate students. Work from this project lead to significant additions and improvements to the chemical mechanism in the grass-roots community model GEOS-Chem, which is used around the world for atmospheric chemistry research.
Last Modified: 11/13/2018
Modified by: Becky Alexander
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