2006 Progress Report: Emissions Inventory and Process Reconciliation Using Molecular Markers and Hybrid/Inverse Photochemical Modeling with Direct Sensitivity Analysis

EPA Grant Number: R831076
Title: Emissions Inventory and Process Reconciliation Using Molecular Markers and Hybrid/Inverse Photochemical Modeling with Direct Sensitivity Analysis
Investigators: Russell, Armistead G. , Odman, Mehmet Talat , Zheng, M.
Institution: Georgia Institute of Technology
EPA Project Officer: Chung, Serena
Project Period: November 1, 2003 through October 30, 2006 (Extended to September 30, 2008)
Project Period Covered by this Report: November 1, 2005 through October 30, 2006
Project Amount: $449,899
RFA: Measurement, Modeling, and Analysis Methods for Airborne Carbonaceous Fine Particulate Matter (PM2.5) (2003) RFA Text |  Recipients Lists
Research Category: Air , Air Quality and Air Toxics , Particulate Matter

Objective:

The goal of this project is to develop and improve integrated source/receptor-based methods for source apportionment of fine aerosol. Further, the results are to be used to identify weaknesses in current emissions inventories for organic carbon.

Progress Summary:

Main tasks for this year were: (1) field sampling at highway, urban, and rural sites during winter time; (2) experimental study on the samples collected in summer and winter; (3) investigation of chemical composition and source contributions for PM2.5 in Atlanta, GA; (4) in-depth study on reconciliation between Community Multiscale Air Quality (CMAQ) and Chemical Mass Balance (CMB) models; (5) studies on changes in aerosol yield and level of secondary organic aerosol (SOA) due to new SOA treatment; (6) sensitivity analysis of SOA parameters; and (7) perform air quality and inverse modeling of a 13-month period. We completed, or made significant progress, on each of the tasks above as discussed below.

Experimental Study on the Samples Collected in Summer 2005 and Winter 2006

Three-channel particle composition monitors (PCM) and high-volume samplers were used to collect particle phase ambient samples during a winter episode, January 2006. Three sampling sites, same as the ones in 2005 summer activities, were utilized: a highway site (directly beside the I-75/85 connector in the middle of Atlanta, which was dominated by on-road emissions); a more typical urban site (in the Georgia Institute of Technology campus); and a rural site (Yorkville, biogenic emission and regional transport impacted). 12-hr PCM and high-volume (hi-vol) samples were collected both at the highway and the urban sites. Simultaneously, 24-hr PCM and hi-vol samples were taken at the rural site. Particle phase chemical speciation of PM2.5 was measured including PM2.5 mass, organic carbon (OC), elemental carbon (EC), trace metals, and ions. PM2.5 mass was measured with a gravimetric method in Georgia Institute of Technology. OC and EC were analyzed in Georgia Institute of Technology with the IMPROVE carbon analysis approach (Interagency Monitoring of Protected Visual Environments). Trace metals were measured at Desert Research Institute (DRI) via X-ray fluorescence (XRF). Ionic species were quantified via IC (ion chromatography) in Georgia Institute of Technology.

Investigation of Chemical Composition and Source Contributions for PM2.5

Temporal and spatial variation of PM2.5 mass and composition were compared and investigated. The results indicated that on-road vehicle emission dominates ambient EC concentrations nearby the roadside. However, this impact dramatically decreased with increasing of the distance from roadside. Within a distance of 450 meters from the I-85/75 highway site to Georgia Institute of Technology campus monitoring site, ambient EC and OC dropped by 74 percent and 35 percent, respectively. In the summer time, the average ambient OC and EC data were 8.2 and 4.0 μg m3, 5.2 and 1.0 μg m-3, 3.8 and 0.2 μg m-3 at the highway roadside, Georgia Institute of Technology campus and Yorkville site, respectively. In winter time, ambient OC and EC data are on average 5.1 and 2.7 μg m-3, 3.6 and 0.9 μg m-3, 2.1 and 0.3 μg m-3 at the three sampling sites above, respectively. Higher OC concentrations in summer time imply strong photochemical activities, which lead to accumulated secondary organic aerosol (SOA) in PM2.5.

Reconciliation Between an Emissions Based Model and Receptor Models—Comparison of Simulated Molecular Markers and Measurements

An in-depth study on comparison of CMAQ-MM and CMB models was made. Source apportionment results using CMAQ were combined with the source profiles, and then compared with measurements. Some of the simulated molecular markers are in good agreement with measurements, but some are not. It is suspected that emissions for mobile sources are underestimated in the winter, and emissions from natural gas are overestimated in the current emission inventories. Possibility of decay of levoglucosan in the summer, and increased condensation of hopanes and steranes in the winter are raised. These results have been put in a manuscript for publication and are presented, briefly, below.

Studies on Aerosol Yield and Level of SOA, and Sensitivity Analysis

Four possible changes in biogenic and anthropogenic SOA were examined this year. The first modification was to add additional biogenic SOA from isoprene, and the second change was to increase anthropogenic SOA. Both changes resulted in increased SOA due to increased pre-existing organic particles. The third one was impact of vapor pressure of semi-volatile organic carbon (SVOC) and the last was the impact of mass stochiometric coefficients. Both tests increased SOA level with different reason. In the third test, SOA was increased due to an increase in particle phase organic matter, and in the fourth test, SOA was increased due to increased SVOCs. The last two tests also suggest that SOA concentrations are sensitive to both parameters and uncertainties in the parameters may cause underestimation of SOA in summer.

Future Activities:

During the last year of the project, major activities include:

  • Final reconciliation of measurements and both receptor modeling and CMAQ-MM modeling.
  • Analysis of biogenic SOA molecular marker species for use in both CMB-MM and CMAQ-MM modeling.
  • Identification of biases in the emissions inventories for carbonaceous PM.
  • Inverse modeling of elemental and organic PM.
  • Analysis of 84 high volume samples for primary and secondary organic tracers with the optimal GC/MS (gas chromatography/mass spectroscopy) methodology.
  • To estimate the fraction of primary vs. secondary organic aerosol (SOA) and the fractions of biogenic and anthropogenic contributions in PM2.5.
  • Comparison of measured secondary organic tracers with simulated values.
  • Manuscript preparation and final report.


Journal Articles on this Report : 3 Displayed | Download in RIS Format

Other project views: All 75 publications 40 publications in selected types All 40 journal articles
Type Citation Project Document Sources
Journal Article Napelenok SL, Cohan DS, Hu Y, Russell AG. Decoupled direct 3D sensitivity analysis for particulate matter (DDM-3D/PM). Atmospheric Environment 2006;40(32):6112-6121. R831076 (2006)
R831076 (Final)
R832159 (2005)
R832159 (2006)
R832159 (2007)
R832159 (Final)
  • Full-text: Science Direct-Full Text HTML
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  • Abstract: Science Direct-Abstract
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  • Other: Science Direct-Full Text PDF
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  • Journal Article Park S-K, Marmur A, Kim SB, Tian D, Hu Y, McMurry PH, Russell AG. Evaluation of fine particle number concentrations in CMAQ. Aerosol Science and Technology 2006;40(11):985-996. R831076 (2005)
    R831076 (2006)
    R831076 (Final)
    R830960 (Final)
    R832159 (2005)
    R832159 (2006)
    R832159 (2007)
    R832159 (Final)
  • Full-text: Taylor & Francis-Full Text HTML
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  • Abstract: Taylor & Francis-Abstract
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  • Other: Taylor & Francis-Full Text PDF
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  • Journal Article Park S-K, Cobb CE, Wade K, Mulholland J, Hu Y, Russell AG. Uncertainty in air quality model evaluation for particulate matter due to spatial variations in pollutant concentrations. Atmospheric Environment 2006;40(Suppl 2):563-573. R831076 (2006)
    R831076 (Final)
    R830960 (Final)
    R832159 (2005)
    R832159 (2006)
    R832159 (2007)
    R832159 (Final)
  • Full-text: Science Direct-Full Text HTML
    Exit
  • Abstract: Science Direct-Abstract
    Exit
  • Other: Science Direct-Full Text PDF
    Exit
  • Supplemental Keywords:

    secondary organic aerosol, SOA, air quality modeling, PM2.5,, RFA, Health, Scientific Discipline, Air, Ecosystem Protection/Environmental Exposure & Risk, particulate matter, Air Quality, air toxics, Environmental Chemistry, climate change, Air Pollution Effects, Risk Assessments, Monitoring/Modeling, Environmental Monitoring, Engineering, Chemistry, & Physics, Environmental Engineering, Atmosphere, carbon aerosols, air quality modeling, particle size, atmospheric particulate matter, health effects, aerosol particles, atmospheric particles, mass spectrometry, human health effects, ambient air monitoring, air modeling, air quality models, air sampling, gas chromatography, thermal desorption, carbon particles, air quality model, emissions, molecular markers, direct sensitivity analysis, particulate matter mass, human exposure, ambient particle health effects, particle phase molecular markers, photchemical modeling, aersol particles, particle dispersion, aerosol analyzers

    Relevant Websites:

    http://www.ce.gatech.edu/~trussell/lamda/index.htm Exit

    Progress and Final Reports:

    Original Abstract
  • 2004 Progress Report
  • 2005 Progress Report
  • 2007 Progress Report
  • Final Report