Grantee Research Project Results
2022 Progress Report: Development, validation and integration of a new model-ready parameterization of N2O5 heterogeneous chemistry.
EPA Grant Number: R840006Title: Development, validation and integration of a new model-ready parameterization of N2O5 heterogeneous chemistry.
Investigators: Bertram, Timothy , Holloway, Tracey
Institution: University of Wisconsin - Madison
EPA Project Officer: Chung, Serena
Project Period: August 1, 2020 through July 31, 2023 (Extended to July 31, 2025)
Project Period Covered by this Report: August 1, 2021 through July 31,2022
Project Amount: $798,234
RFA: Chemical Mechanisms to Address New Challenges in Air Quality Modeling (2019) RFA Text | Recipients Lists
Research Category: Air , Air Quality and Air Toxics
Objective:
The primary objective of this proposal is development and validation of a new chemically based parameterization for γ(N2O5) and Φ(ClNO2) that accounts for recent insights from laboratory and field measurements of N2O5 and ClNO2 heterogeneous chemistry, with a specific focus on the role of phase separation and aerosol water in regulating reactive uptake of N2O5. The chemically based parameterization will be constructed such that they can be readily integrated into CMAQv5.3 leveraging new advances in organic aerosol treatment in the model.
Progress Summary:
During year one, we focused on the testing and implementation of a modified version of the Gaston et al. (2014) N2O5 parameterization to account for the dependencies of γ(N2O5) on aerosol composition and phase. In year two, we focus on ClNO2 chemistry. Four combinations of Φ(ClNO2) and γ(N2O5) parameterizations were tested within CMAQ. These four combinations were compared with flight data for Φ(ClNO2) and γ(N2O5) from the WINTER 2015 campaign. More specifically, we implemented a new parameterization for ClNO2 production based on recent laboratory and field measurements that suggest that sulfate can act to catalyze the hydrolysis of N2O5, thus reducing the ClNO2 yield. However, when testing these parameterizations, our initial results suggest that the two parameterizations are quite similar. Specifically, at a 95% confidence, a comparison of the two Φ(ClNO2) parameterizations failed to reject the null hypothesis (𝐷=0.01,𝑝=0.997) indicating that the two model parameterization combinations were not statistically different. We are currently extracting N2O5 and ClNO2 concentrations along the flight track of the WINTER campaign for comparison with CMAQ.
Future Activities:
Our year 3 objectives center on assessing CMAQ representations of γ(N2O5) and Φ(ClNO2) using early morning tropospheric column NO2 measurements from Pandora (ground-based) and TEMPO (future satellite) and assess the response of model O3 and PM to updated nocturnal NOx chemistry.
References:
Gaston, C. J., Thornton, J. A., and Ng, N. L. Reactive uptake of N2O5 to internally mixed inorganic and organic particles: the role of organic carbon oxidation state and inferred organic phase separations, Atmospheric Chemistry and Physics, 14, 5693–5707, https://doi.org/10.5194/acp-14-5693-2014, 2014.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
Other project views: | All 1 publications | 1 publications in selected types | All 1 journal articles |
---|
Type | Citation | ||
---|---|---|---|
|
Bergin RA, Harkey M, Hoffman A, Moore RH, Anderson B, Beyersdorf A, Ziemba L, Thornhill L, Winstead E, Holloway T, Bertram TH. Observation-based constraints on modeled aerosol surface area:implications for heterogeneous chemistry. Atmospheric Chemistry and Physics 2022;22:15449–68. |
R840006 (2022) R840006 (2023) |
Exit |
Supplemental Keywords:
air quality, particulate nitrate, heterogeneous and multiphase chemistryRelevant Websites:
The Holloway Group at SAGE Exit , The Bertram Research Group Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.