Grantee Research Project Results

Source-Oriented Chemical Transport Model for Primary and Secondary Organic Aerosol

EPA Grant Number: R831082
Title: Source-Oriented Chemical Transport Model for Primary and Secondary Organic Aerosol
Investigators: Kleeman, Michael J. , Griffin, Robert J. , Clegg, Simon
Institution: University of California - Davis , University of New Hampshire
EPA Project Officer: Chung, Serena
Project Period: October 1, 2003 through September 30, 2006 (Extended to September 30, 2008)
Project Amount: $450,000
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

Description:

Primary Organic Aerosol (POA) and Secondary Organic Aerosol (SOA) contribute significantly to airborne PM2.5 concentration throughout the United States. Our current understanding about the most significant sources of POA and SOA are limited by the capabilities of receptor-oriented statistical models. In this research we will construct a source-oriented Chemical Transport Model that can identify source contributions to POA and SOA concentrations with improved accuracy and resolution relative to receptor-oriented techniques.

Approach:

A state-of-the-art secondary organics module that considers activity coefficient corrections for organic-organic and organic-inorganic interactions will be combined with a host source-oriented CTM. The vapor pressure of organic species above the surface of particles released from different sources will be predicted based on thermodynamic principals. The dynamic exchange of semi-volatile organic compounds between the gas and particle phases will be calculated based on particle size, vapor pressure, gas-phase diffusivity, and interfacial mass transfer. The new source-oriented CTM with improved SOA calculations will be used to predict concentrations of elemental carbon (EC), POA, and SOA at EPA Supersite locations in Los Angeles, Fresno, and St. Louis. The sources of POA and SOA will be identified through the unique features of the source-oriented CTM.

Expected Results:

Source contributions to EC, POA, and SOA will be identified at three heavily polluted locations: Los Angeles, Fresno, and St. Louis. This will improve our understanding of the health risk posed by different emissions sources in these heavily populated areas. The influence of internal vs. external mixture and bulk equilibrium vs. size-resolved dynamic approaches on predicted SOA formation in air quality models will be quantified so that appropriate techniques can be used in the future. The likely impact of interactions between inorganic and soluble organic compounds in aerosol particles on SOA formation and aerosol water uptake will be established. This will result in a more cost effective allocation of federal and state environmental protection resources during future air quality modeling exercises.

Publications and Presentations:

Publications have been submitted on this project: View all 28 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 13 journal articles for this project

Supplemental Keywords:

secondary organic aerosols, source-oriented chemical transport model, source apportionment, inorganic ? organic interactions., RESEARCH, RFA, Air, Ecosystem Protection/Environmental Exposure & Risk, Scientific Discipline, particulate matter, Air Quality, Environmental Chemistry, Engineering, Chemistry, & Physics, Analytical Chemistry, Monitoring/Modeling, Air Pollution Effects, air toxics, Environmental Engineering, Environmental Monitoring, Monitoring, aerosol particles, health effects, source oriented CMT, atmospheric dispersion models, secondary organic aerosol, particle size, air sampling, gas chromatography, mass spectrometry, carbon particles, emissions, monitoring stations, air quality modeling, measurement methods, human exposure, modeling studies, secondary organic aerosols, thermal desorption, particulate matter mass, air quality model, carbon aerosols, aerosol analyzers, particle phase molecular markers, air quality models, atmospheric particulate matter, transport modeling, particle dispersion, human health effects, atmospheric measurements, modeling, monitoring of organic particulate matter

Progress and Final Reports:

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.