Protocol for Applying and Validating the CMB Model for PM2.5 and VOC EPA-451/R-04-001 December 2004 Protocol for Applying and Validating the CMB Model for PM2.5 and VOC By: John G. Watson et al. Desert Research Institute University and Community College System of Nevada Reno, NV 89512 Prepared for: C. Thomas Coulter and Charles W. Lewis, Project Officers U.S. Environmental Protection Agency Research Triangle Park, NC 27711 Contract No. 5D1808NAEX US. Environmental Protection Agency Office of Air Quality Planning & Standards Emissions, Monitoring & Analysis Division Air Quality Modeling Group i ACKNOWLEDGMENTS This revised protocol for applying and validating the Chemical Mass Balance Model (CMB) was originally developed by Desert Research Institute (DRI) of trhe University and Community College System of Nevada under Contract 5D1808NAEX with EPA’s Office of Air Quality Planning & Standards. The Project Officers were C. Thomas Coulter1 and Charles W. Lewis.2 Substantial contributions to the initial draft of this protocol were made by DRI staff members John G. Watson, Judith C. Chow, and Eric M. Fujita. Tom Coulter spent considerable time reviewing and reformatting the protocol, and harmonizing it with the latest version of CMB: EPA-CMB8.2. He also developed and produced its Appendixes A, B and G. DISCLAIMER This protocol was reviewed by EPA for publication. The information presented here does not necessarily express the views or policies of the U.S. Environmental Protection Agency or the State of Nevada. The mention of commercial hardware and software in this document does not constitute endorsement of these products. No explicit or implied warranties are given for the software and data sets described in this document. 1Air Quality Modeling Group, Office of Air Quality Planning & Standards; Research Triangle Park, NC 27711 2National Exposure Research Laboratory, Office of Research & Development; Research Triangle Park, NC 27711 ii Table of Contents Page 1. Introduction ............................................................. 1-1 1.1 Protocol Objectives................................................... 1-1 1.2 CMB Model Development and History ................................... 1-2 1.3 Protocol Overview.................................................... 1-3 2. CMB Relationships with Other Air Quality Models .............................. 2-1 2.1 Conceptual Models ................................................... 2-1 2.2 Emissions Models.................................................... 2-1 2.3 Meteorological Models................................................ 2-2 2.4 Chemical Models..................................................... 2-3 2.5 Source Dispersion Model .............................................. 2-3 2.6 Receptor Models ..................................................... 2-4 3. CMB Source and Receptor Input Data ........................................ 3-1 3.1 Source Profiles....................................................... 3-1 3.1.1 Common Emissions Sources ....................................... 3-1 3.1.2 Source Profile Normalization Options ................................ 3-2 3.1.3 PM2.5 Source Characteristics....................................... 3-6 3.1.4 VOC Source Characteristics ...................................... 3-11 3.1.5 Source Characterization Methods .................................. 3-14 3.1.6 Source Profile Data Bases ........................................ 3-16 3.2 Receptor Measurements .............................................. 3-17 3.2.1 Physical and Chemical Characteristics of Receptor Concentrations ........ 3-17 3.2.2 Receptor Characterization Methods ................................. 3-19 3.2.3 Sampler Siting ................................................. 3-28 3.2.4 Temporal Variability ............................................ 3-30 3.2.5 Receptor Measurement Data Bases ................................. 3-31 3.3 CMB Application Levels.............................................. 3-31 4. Assumptions, Performance Measures, and Validation Procedures................... 4-1 4.1 Fundamental Assumptions and Potential Deviations ......................... 4-1 4.2 CMB Performance Measures ........................................... 4-4 4.3 Protocol Steps ...................................................... 4-14 4.3.1 Determine the Applicability of CMB ............................... 4-14 4.3.2 Format Input Files and Perform Initial Model Runs .................... 4-14 4.3.3 Evaluate Outputs and Performance Measures ......................... 4-17 4.3.4 Evaluate Deviations from Model Assumptions ........................ 4-17 4.3.5 Modify Model Inputs to Remediate Problems ......................... 4-17 4.3.6 Evaluate the Consistency and Stability of the Model Results ............. 4-19 4.3.7 Corroborate CMB Results with Other Modeling and Analyses ........... 4-20 iii Table of Contents (continued) Page 5. Example of Application and Validation for PM2.5 ............................... 5-1 5.1 Model Applicability .................................................. 5-1 5.2 Initial Source Contribution Estimates ..................................... 5-6 5.3 Model Outputs and Performance Measures ............................... 5-15 5.4 Deviations from Model Assumptions.................................... 5-15 5.5 Identification and Correction of Model Input Errors ........................ 5-17 5.6 Consistency and Stability of Source Contributions .......................... 5-17 5.7 Consistency with Other Simulations and Data Analyses ..................... 5-18 6. Example of Application and Validation for VOC................................ 6-1 6.1 Model Applicability .................................................. 6-1 6.2 Initial Source Contribution Estimates ..................................... 6-1 6.3 Examine Model Outputs and Performance Measures......................... 6-4 6.4 Test Deviations from Model Assumptions ................................. 6-5 6.5 Identify and Correct Model Input Errors ................................... 6-7 6.6 Evaluate Consistency and Stability of Source Contributions ................... 6-7 6.7 Determine Consistency with Other Simulations and Data Analyses ............. 6-7 7. Summary, Conclusions, and Future Prospects................................... 7-1 8. References.............................................................. 8-1 APPENDIX A. 54 PAMS target compounds (hydrocarbons) listed in their elution sequence A-1 APPENDIX B. Normalization for the VOC Source Profile...........................B-1 APPENDIX C. Internet Links to Modeling Software and Data Sets....................C-1 APPENDIX D. CMB Mathematics ............................................ D-1 APPENDIX E. Summary of CMB PM10 Source Apportionment Studies ................E-1 APPENDIX F. Summary of CMB VOC Source Apportionment Studies ................F-1 APPENDIX G. Procedures for Treating Secondary Particles ........................ G-1 iv List of Tables Page Table 3.1-1 Chemicals from Particles in Different Emissions Sources ................ 3-8 Table 3.1-2 Organic Compounds Found in Different Source Emissions and in Ambient Air 3-9 Table 3.2-1 Chemical Compounds, Mnemonics, and Measurement Methods for Particle and VOC Receptor Modeling ......................................... 3-20 Table 4.2-1 CMB8 Outputs and Performance Measures ........................... 4-9 Table 5.1-1 Wintertime Emissions Inventory for Denver Metro Area ................. 5-2 Table 5.1-2 Source Composition Profiles from NFRAQS .......................... 5-3 Table 5.1-3 Source Composition Profiles from the 1987 Scenic Denver Study and Other Studies........................................................ 5-5 Table 5.2-1a Sensitivity of Total Carbon Apportionment to Alternative Wood Combustion Profiles (Welby, 01/17/97 at 0600 to 1200 MST) ....................... 5-7 Table 5.2-1b Sensitivity of Total Carbon Apportionment to Alternative Meat Cooking Profiles (Welby, 01/17/97 at 0600 to 1200 MST) .............................. 5-8 Table 5.2-2a Sensitivity of Total Carbon Apportionment to Alternative Cold-Start Profiles (Welby, 01/17/97 at 0600 to 1200 MST) .............................. 5-9 Table 5.2-2b Sensitivity of Total Carbon Apportionment to Alternative Hot-Stabilized and High Particle Emitter Profiles (Welby, 01/17/97 at 0600 to 1200 MST) .... 5-10 Table 5.2-2c Sensitivity of Total Carbon Apportionment to Fitting Species (Welby, 01/17/97 at 0600 to 1200 MST) ............................................. 5-11 Table 6.2-1 VOC Source Profiles for NARSTO-NE CMB ......................... 6-2 Table 6.2-2 PAMS Measured Species and CMB Fitting Species ..................... 6-3 Table 6.3-1 CMB Sensitivity Tests for Vehicle Exhaust Profiles ..................... 6-4 Table 6.3-2 CMB Sensitivity Tests for Different Profiles .......................... 6-5 v List of Figures Page Figure 3.2-1 Spatial distribution of average PM2.5 source contributions from gasoline exhaust, diesel exhaust, suspended dust, vegetative burning, secondary ammonium sulfate, secondary ammonium nitrate, and primary coal-fired power station fly ash in and near Denver, CO during winter, 1996-97. ............................ 3-29 Figure 3.2-2 PM2.5 source contributions at the Welby site north of Denver, CO during winter of 1996-97. ...................................................... 3-30 Figure 4.2-1 CMB8 source contribution display. .................................. 4-5 Figure 4.2-2 Eligible space collinearity display.