Grantee Research Project Results

2004 Progress Report: Secondary Aerosol Formation from Gas and Particle Phase Reactions of Aromatic Hydrocarbons

EPA Grant Number: R831084
Title: Secondary Aerosol Formation from Gas and Particle Phase Reactions of Aromatic Hydrocarbons
Investigators: Kamens, Richard M.
Institution: University of North Carolina at Chapel Hill
EPA Project Officer: Chung, Serena
Project Period: July 28, 2003 through July 27, 2006 (Extended to July 27, 2008)
Project Period Covered by this Report: July 28, 2003 through July 27, 2004
Project Amount: $400,000
RFA: Measurement, Modeling, and Analysis Methods for Airborne Carbonaceous Fine Particulate Matter (PM2.5) (2003) RFA Text | Recipients Lists
Research Category: Particulate Matter , Air Quality and Air Toxics , Air

Objective:

The objective of this research project is to develop a “new generation” aromatic chemical mechanism that can integrate newly discovered particle-phase heterogeneous processes with the known gas-phase chemistry as a unified, multiphase, chemical reaction mechanism that ultimately will permit the prediction of secondary organic aerosol (SOA) formation in the aromatic system. This research project focuses on the elucidation of the fundamental chemistry that brings about the SOA formation from aromatic reactions in the atmosphere.

Progress Summary:

During the reporting period, we: (1) developed a working chemical mechanism for toluene that reasonably predicts the gas-phase chemistry and also has potential to predict the SOA formation from toluene oxidation; (2) completed a series of toluene/NO_x daytime outdoor smog chamber experiments at different initial concentrations and environmental conditions; and (3) performed some preliminary experiments with the major toluene oxygenated aldehyde products. An illustration of our preliminary model’s ability to fit the chamber data is shown in Figure 1.

(Top) Comparison of Observed (Solid Line) and Simulated (Dashed Line) Time Dependence of NO, NO<sub>2</sub> and O<sub>3</sub> and (Bottom) Simulation (Dash) of Total Measured Particle Mass (Symbols)

Figure 1. (Top) Comparison of Observed (Solid Line) and Simulated (Dashed Line) Time Dependence of NO, NO₂ and O₃ and (Bottom) Simulation (Dash) of Total Measured Particle Mass (Symbols)

Future Activities:

We will continue detailed product analysis of the samples from the toluene chamber experiments in winter 2004/2005. . We also will continue with our modeling of these systems. We have begun to conduct some experiments with p-xylene, and this work will continue. We also will analyze our particle size data and characterize post nucleation particles (7-15 nm) that we have observed in some of our experiments.

Journal Articles:

No journal articles submitted with this report: View all 8 publications for this project

Supplemental Keywords:

secondary organic aerosol formation, SOA, aromatics, modeling, organic particle formation, toluene, oxidation, gas-phase chemistry,, RFA, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Environmental Chemistry, Monitoring/Modeling, Atmospheric Sciences, Environmental Monitoring, air quality, secondary organic aerosol, particle phase reactions, gas phase chemistry, environmental measurement, Toluene, organic chemistry, aerosol analyzers

Progress and Final Reports:

Original Abstract

The 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.