Grantee Research Project Results
2017 Progress Report: Effects of Ammonia on Secondary Organic Aerosol Formation in a Changing Climate
EPA Grant Number: R835881Title: Effects of Ammonia on Secondary Organic Aerosol Formation in a Changing Climate
Investigators: Dabdub, Donald , Nizkorodov, Sergey
Institution: University of California - Irvine
EPA Project Officer: Chung, Serena
Project Period: January 1, 2016 through December 31, 2018 (Extended to December 31, 2021)
Project Period Covered by this Report: January 1, 2017 through December 31,2017
Project Amount: $701,304
RFA: Particulate Matter and Related Pollutants in a Changing World (2014) RFA Text | Recipients Lists
Research Category: Air , Climate Change
Objective:
The goal of this research is to explore systematically the effect of the reactive uptake of ammonia (NH3) by secondary organic aerosols (SOA) on the yield, chemical composition and optical properties of anthropogenic and biogenic SOA using both experimental and modeling approaches. Targeted laboratory experiments are performed in which SOA are prepared under controlled conditions in a smog chamber; aged by ammonia; and examined with a suite of instruments that measure SOA yield, detailed molecular level composition and optical absorption coefficient. The results of these observations are implemented in state-of-the-art air pollution models at different scales: (1) urban-scale modeling of the South Coast Air Basin of California with a comprehensive chemical mechanism, (2) modeling at the continental scale using the CMAQ model with a domain that covers the entire contiguous United States, and (3) simulations of future climate scenarios at the continental scale using the Community Multiscale Air Quality (CMAQ) model to explore the impact of future climate change on SOA formation. These modeling systems help improve our understanding of air pollution and air quality modeling capabilities.
Progress Summary:
The goals of the project have not changed from the original application, and excellent progress has been made on the tasks described in the project proposal.
Lab experiments aligned with Task 1 were performed during 2017 to probe the efficiency with which ammonia can be taken up by different types of atmospheric SOA. The experiments made it possible to set a reasonable limit on the maximal possible extent of the NH3+SOA reactions, which was critically important for the modeling efforts. Modeling efforts during this period have focused on model development with the goal of improving air quality modeling capabilities, including the development and implementation of a novel chemical mechanism to simulate the reactive uptake of ammonia by SOA, a process that is not yet included in any of the current air quality models (except ours). We use a variety of air quality modeling tools, including the UCI-CIT (University of California, Irving-California Institute of Technology) model to simulate air quality at the urban scale and CMAQ model to simulate air quality at the continental scale. The UCI-CIT modeling study investigating the reactive uptake of NH3 by SOA that began during the first period was continued and expanded with additional scenarios to incorporate the results of the laboratory experiments performed during the first two periods and further investigate the sensitivity of ammonia uptake to the key parameters included in the model. This study is complete and has been submitted for publication in Atmospheric Environment and currently is under review.
A new modeling study was conducted using the CMAQ model, building upon the methodology developed in the UCI-CIT modeling study to simulate the reactive uptake of ammonia by SOA. This study extends the analysis to the national level, using a modeling domain that covers the continental United States. Simulation results from this study are compared extensively to ambient measurement data to validate model performance with the inclusion of the new chemistry, a key result for ensuring accurate prediction of PM2.5 concentrations in National Ambient Air Quality Standards (NAAQS) attainment demonstrations. Overall, the chemical mechanism we developed and implemented into the CMAQ model in this study is found to improve model performance with respect to the simulation of key atmospheric pollutants. This study is complete and has been published in Atmospheric Chemistry and Physics.
Future Activities:
Laboratory experiments during the next period will focus on quantification of reactive uptake coefficients for ammonia on different types of SOA as a function of relative humidity (RH). With the information on RH dependence of the uptake coefficients we will be able to model the ammonia chemistry more accurately in different atmospheric environments, ranging from dry to humid. Revisions to the UCI-CIT modeling manuscript are expected after receiving feedback from reviewers. The continental modeling capabilities that we established during the second period lay the foundation for conducting the simulations of climate change effects on SOA formation, which will be the focus of the modeling efforts during the next period. The parameterization of the reactive uptake of ammonia by SOA that we implemented into the CMAQ model's chemical mechanism will continue to be refined as additional results from laboratory experiments become available, further improving model performance.
Journal Articles on this Report : 4 Displayed | Download in RIS Format
Other project views: | All 47 publications | 12 publications in selected types | All 11 journal articles |
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Hinks ML, Montoya-Aguilera J, Ellison L, Lin P, Laskin A, Laskin J, Shiraiwa M, Dabdub D, Nizkorodov SA. Effect of relative humidity on the composition of secondary organic aerosol from the oxidation of toluene. Atmospheric Chemistry and Physics 2018;18(3):1643-1652. |
R835881 (2017) R835881 (2018) R835881 (2020) |
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Horne JR, Dabdub D. Impact of global climate change on ozone, particulate matter, and secondary organic aerosol concentrations in California: A model perturbation analysis. Atmospheric Environment 2017;153:1-17. |
R835881 (2016) R835881 (2017) R835881 (2020) |
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Montoya-Aguilera J, Horne JR, Hinks ML, Fleming LT, Perraud V, Lin P, Laskin A, Laskin J, Dabdub D, Nizkorodov SA. Secondary organic aerosol from atmospheric photooxidation of indole. Atmospheric Chemistry and Physics 2017;17(18):11605-11621. |
R835881 (2017) R835881 (2020) |
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Zhu S, Horne JR, Montoya-Aguilera J, Hinks ML, Nizkorodov SA, Dabdub D. Modeling reactive ammonia uptake by secondary organic aerosol in CMAQ:application to continental US. Atmospheric Chemistry and Physics 2018;18(5):3641-3657. |
R835881 (2017) R835881 (2018) R835881 (2020) R835881 (Final) |
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Supplemental Keywords:
air, ambient air, atmosphere, ozone, global climate, tropospheric, VOC, SOA, oxidants, nitrogen oxides, organic, environmental chemistry, engineering, modelingProgress 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.
Project Research Results
- Final Report
- 2020 Progress Report
- 2019 Progress Report
- 2018 Progress Report
- 2016 Progress Report
- Original Abstract
11 journal articles for this project