Grantee Research Project Results
2018 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, 2018 through December 31,2018
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 (SoCAB) 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 regional and continental scale using the 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 2018 to probe the efficiency with which ammonia can be taken up by different types of atmospheric SOA and investigated the NH3uptake dependence on relative humidity. Those experiments consolidated our understanding of the maximum possible extent to which the NH3+ SOA reactions occur, which was critically important for further modeling efforts. Modeling efforts during this period have focused on model development with the goal of improving the understanding between the emissions inventory, climate change and air quality impact, as well as improving air quality modeling capabilities for simulating meteorological-air quality feedbacks. A variety of air quality modeling tools were employed, including the UCI-CIT model to simulate air quality at the urban scale (Task 3), the CMAQ (version 5.2) model to simulate air quality at the continental scale (Task 6), and the WRF-CMAQ (version 5.2) model to simulate meteorological-air quality two-way feedbacks. First, revisions were made to the manuscript regarding the NH3uptake effect by SOA on urban scale using the UCI-CIT model that began during the first period and submitted in the second period, and the paper was published inAtmospheric Environment(Task 2 and Task 3). Second, revisions to the submitted manuscript for the study of the NH3uptake effect by SOA over the continental U.S. using the CMAQ model that began in the second period were completed, and the paper was published inAtmospheric Chemistry and Physics(Task 2 and Task 6). Third, a new modelling study was conducted using the CMAQ model to investigate the potential impact of an underestimated VOC inventory on air quality, including impacts on SOA concentrations which are the base for the NH3uptake mechanism (Task 6). This study has been submitted for publication inAtmospheric Environmentand is currently under review. Additionally, a comprehensive study was conducted using the CMAQ model during the third period to quantify the effect of climate change on pollutant concentrations at a regional level under different mitigation polices (Task 4 and Task 6). This study is complete and has been submitted for publication inEnvironment Internationaland is currently under review. Finally, we expanded our modeling capability by acquiring the new coupled meteorological-air quality model WRF-CMAQ. This model is able to simulate the two-way feedback between the air quality and the meteorology. The acquisition of the WRF-CMAQ modeling system lays the foundation for applying our SOA-NH3uptake mechanism to studying possible feedbacks between meteorology-chemistry-aerosols on short- and medium-term scales (Task 5).
Future Activities:
Laboratory experiments during the next period will continue to explore the effect of humidity on NH3 uptake, expand the types of SOA studied to include more viscous SOA (e.g. SOA produced from sesquiterpenes), and compare the SOA uptake of NH3to that of other atmospheric amines, such as dimethyl amine and butyl amine. 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. The feedbacks between meteorology-chemistry-aerosols on short- and medium-term scales of the SOA-NH3 uptake mechanism will be investigated using the WRF-CMAQ modeling system. 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 : 3 Displayed | Download in RIS Format
Other project views: | All 47 publications | 12 publications in selected types | All 11 journal articles |
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Type | Citation | ||
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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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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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Horne JR, Zhu S, Montoya-Aguilera J, Hinks ML, Wingen L, Nizkorodov SA, Dabdub D. Reactive uptake of ammonia by secondary organic aerosols:implications for air quality. Atmospheric Environment 2018;189:1-8. |
R835881 (2018) R835881 (2020) |
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Supplemental Keywords:
air, ambient air, atmosphere, ozone, global climate, tropospheric, VOC, 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
- 2017 Progress Report
- 2016 Progress Report
- Original Abstract
11 journal articles for this project