Grantee Research Project Results

2004 Progress Report: Integrating the Thermal Behavior and Optical Properties of Carbonaceous Particles: Theory, Laboratory Studies, and Application to Field Data

EPA Grant Number: R831085
Title: Integrating the Thermal Behavior and Optical Properties of Carbonaceous Particles: Theory, Laboratory Studies, and Application to Field Data
Investigators: Bond, Tami C.
Institution: University of Illinois Urbana-Champaign
EPA Project Officer: Chung, Serena
Project Period: September 1, 2003 through August 31, 2006 (Extended to August 31, 2008)
Project Period Covered by this Report: September 1, 2003 through August 31, 2004
Project Amount: $247,815
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:

This research relates to the measurement of carbonaceous particles with the common thermal-optical analyzers used at U.S. Environmental Protection Agency monitoring sites. The objectives of this research project are to:

improve the confidence limits of combined thermal/optical transitions of specific fractions of primary carbonaceous aerosols;
confirm to 95 percent confidence that elemental carbon (EC) can be treated as a conserved tracer;
and demonstrate enhanced interpretations of thermal-optical analyses of carbonaceous particles for an existing database of field measurements.

Progress Summary:

We have critically reviewed the literature on light-absorbing aerosol and have used the theory on optics and carbon materials acquired during this review to assess two effects: the temperature dependence of the optics of materials and the change in particle size as the sample is heated. We have developed an optical model of an aerosol-laden filter. This model presently is used to examine how changes in optics and morphology of the particles on the filter might affect the response of the thermal-optical analyzer. In the future, the model also will be used in “inverse” mode to determine which thermal-optical transitions might correspond to certain types of carbon.

We have developed two combustors: one generating hexane soot and one generating smoke or soot from wood combustion. We have acquired and installed a Sunset OC/EC analyzer, and have analyzed nearly 300 samples of generated smoke. Some of these tests were preliminary and were designed to assess the reproducibility of the generation system. Others addressed the question of whether EC changed its thermal/optical response during atmospheric processing. We tested four types of simulated atmospheric processing (exposure to UV, exposure to ozone, mixing with ammonium sulfate, and mixing with potassium chloride), finding large changes with some treatments and minimal changes with others.

Future Activities:

During Year 2 of the project, we will focus on finalizing the optical model, using the results of our laboratory tests to develop input parameters for this model. We also will continue to refine the generation of reproducible aerosol and begin examining specific solvent-extractable components with the methods developed in Year 1 of the project. We also will focus on making the results of this research available to the community through three conference presentations and two journal papers.

Journal Articles:

No journal articles submitted with this report: View all 19 publications for this project

Supplemental Keywords:

ambient air, tropospheric, global climate, environmental chemistry, analytical, measurement methods, air, ecosystem protection/environmental exposure and risk, air pollution effects, air quality, analytical chemistry, atmospheric sciences, engineering, chemistry, and physics, environmental engineering, environmental monitoring, monitoring/modeling, physics, air toxics, particulate matter, PM 2.5, aerosol analyzers, aerosol particles, air modeling, air quality model, air quality modeling, air sampling, airborne particulate matter, atmospheric particles, atmospheric particulate matter, carbon aerosols, carbon particles, chemical characteristics, chemical speciation sampling, emissions, health effects, modeling studies, particle dispersion, particle phase molecular markers, particle size, particle size measurement, particulate matter mass, particulate organic carbon, thermal desorption, thermal properties,, RFA, Scientific Discipline, Air, Ecosystem Protection/Environmental Exposure & Risk, particulate matter, Air Quality, Environmental Chemistry, Engineering, Chemistry, & Physics, Analytical Chemistry, Monitoring/Modeling, Air Pollution Effects, Atmospheric Sciences, air toxics, Environmental Engineering, Environmental Monitoring, aerosol particles, health effects, particle size, air sampling, carbon particles, emissions, chemical characteristics, air quality modeling, measurement methods, aersol particles, airborne particulate matter, thermal properties, atmospheric particles, modeling studies, thermal desorption, particulate matter mass, air quality model, particulate organic carbon, carbon aerosols, aerosol analyzers, particle phase molecular markers, air quality models, atmospheric particulate matter, ultrafine particulate matter, chemical speciation sampling, particle size measurement, particle dispersion, air modeling

Relevant Websites:

http://sftp.cee.uiuc.edu/research/bondresearch Exit

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.