The Effect of Ammonia on Organic Aerosols in a Changing Climate

EPA Grant Number: R835882
Title: The Effect of Ammonia on Organic Aerosols in a Changing Climate
Investigators: Weber, Rodney J. , Ng, Nga Lee , Russell, Armistead G. , Huey, Greg
Current Investigators: Weber, Rodney J. , Russell, Armistead G. , Ng, Nga Lee , Huey, Greg
Institution: Georgia Institute of Technology
EPA Project Officer: Chung, Serena
Project Period: January 1, 2016 through December 31, 2018 (Extended to December 31, 2020)
Project Amount: $789,261
RFA: Particulate Matter and Related Pollutants in a Changing World (2014) RFA Text |  Recipients Lists
Research Category: Air , Climate Change


Air quality regulations have resulted in the reduction of many traditional air pollutants, and this trend is expected to continue into the future. Ammonia emissions, however, have not decreased and could be substantially higher in the future from agricultural activities due to a growing global population and changing climate. Emissions of biogenic volatile organic compounds (VOCs), and the resulting secondary organic aerosol (SOA), are also likely to follow ammonia trends. The combination of these factors could substantially alter the formation and chemical and physical properties of PM2.5 in the future. This project will assess how SOA formed under enhanced ammonia will influence air quality, human health and climate.


The proposed research applies advanced air quality monitoring instrumentation for both ambient and environmental chamber studies to investigate the effect of ammonia on biogenic secondary organic aerosols. The implications of these findings to ambient air quality will then be assessed through regional air quality modeling. First, ambient studies will be conducted in a selected location that exhibits enhanced ammonia and biogenic VOC emissions, such as downwind of concentrated animal feeding operations (CAFO) in rural forested Georgia. Gaseous ammonia and organic acids will be measured by chemical ionization mass spectrometry and the aerosol mass, chemistry, toxicity and optical properties by a suite of unique online and off-line instruments. Identical instrumentation and analytical methods will then be applied to controlled environmental chamber experiments, guided by the field study, to determine yields and the mechanistic routes leading to formation of SOA under enhanced ammonia. Air quality modeling will utilize the ambient and chamber findings to assess the broader implications for future air quality, human health and climate in the continental USA.

Expected Results:

This research will provide new understanding on the effects of anticipated tends in ammonia and biogenic VOC emissions on fine particulate matter concentrations and properties that directly impact human health and climate.

Publications and Presentations:

Publications have been submitted on this project: View all 7 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 2 journal articles for this project

Supplemental Keywords:

Particulates, biomass burning, source characterization, measurement methods, environmental chemistry, source characterization, Georgia, Southeast, organics,  biogenic, biosphere, health effects, human health, air quality modeling, air quality analysis, organic acids;

Progress and Final Reports:

  • 2016 Progress Report
  • 2017 Progress Report
  • 2018 Progress Report
  • 2019 Progress Report