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Objectives

Explore the steps and protocols for applying and validating the CMB model in air quality studies. Learn about model outputs, diagnostics, and source contribution estimates.

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Objectives

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  1. Validation And Applications Protocol For Source Apportionment Of Volatile Organic Compounds And Fine Particles Eric M. Fujita ericf@dri.edu John G. Watson Desert Research Institute University and Community College System of Nevada Reno, Nevada 18th AWMA/EPA Symposium on Measurement of Toxic and Related Air Pollutants September 1-3, 1998

  2. Objectives • Describe steps in the CMB applications and validation protocol • Demonstrate CMB model outputs and diagnostics

  3. Protocol for Applying and Validatingthe CMB Model 1. Assess general applicability 2. Configure with source types, source profiles, and chemical species from receptor 3. Examine model statistics and diagnostics. 4. Determine compliance with model assumptions 5. Modify model configuration to better comply with assumptions 6. Test the consistency and stability of CMB results 7. Evaluate the validity of model results

  4. Step 1. General Applicability • Sufficient data to determine excessive pollutant levels • Samples amenable to or have been chemically speciated • Potential source contributors identified • Source profiles measured or approximated • More receptor species than source types

  5. Step 2. Model Configuration • Receptor species: • A value and uncertainty is needed for each species • Only one measurement of a given species should be included in the solution • Values below lower quantifiable limits may be included if uncertainty is set to LQL • Source type selection: • Common area sources • Natural sources • Point sources in emissions inventory • Sources identified preliminary data analyses such as PCA

  6. Step 2. Model Configuration(Continued) • Source profiles in CMB solution: • Upwind point sources • Seasonal emitters • Non-collinear profiles

  7. CMB8 Application Options

  8. Step 3. Outputs and Diagnostics

  9. Step 3. Outputs and Diagnostics(continued)

  10. Step 3. Outputs and Diagnostics(Continued)

  11. Step 3. Outputs and Diagnostics(Continued)

  12. Source Contribution Estimates SOURCE CONTRIBUTION ESTIMATES - SITE: WELBY DATE: 01/17/97 CMB8(97350) SAMPLE DURATION 6 START HOUR 06 SIZE: F R SQUARE .92 PERCENT MASS 92.9 CHI SQUARE .61 DF 71 B and L: No SRC ELIM: No WEIGHTS: CHISQR 1.000 R SQR 1.000 PCMASS 1.000 FRCEST 1.000 SOURCE EST CODE NAME SCE(UG/M3) STD ERR TSTAT ---------------------------------------------------- YES N001 NVNSP 3.32177 2.04933 1.62090 Cold Start Gas YES N007 NVNSP2 .92356 .41105 2.24682 Normal Gas YES N010 NVSM 6.60239 3.71219 1.77857 High Emitter Gas YES N013 NWHD 7.21937 1.83529 3.93364 Diesel YES N050 NMc 1.87745 2.01630 .93114 Meat Cooking YES N055 NWFSc .81366 .47104 1.72739 Softwood Burning YES N067 NWSHc2 2.44912 1.30503 1.87668 Hardwood Burning YES N074 NRDC 5.53905 1.55074 3.57188 Dust YES N082 AMSUL 6.82026 .82871 8.22998 Ammonium Sulfate YES N084 AMNIT 13.69944 1.33690 10.24715 Ammonium Nitrate YES N124 PCHCLC1 .04272 1.19172 .03585 Coal Power Station ---------------------------------------------------- MEASURED CONCENTRATION FOR SIZE: F 53.1+- 2.7

  13. Collinearity Measures ELIGIBLE SPACE DIM. = 11 FOR MAX. UNC. = 10.61606 (20.% OF TOTAL MEAS. MASS) 1 / SINGULAR VALUE -------------------------------------------------------------------------------- .25403 .37757 .74915 .84969 .88558 1.34392 1.36573 1.58813 1.77155 2.17895 4.17763 -------------------------------------------------------------------------------- NUMBER ESTIMABLE SOURCES = 11 FOR MIN. PROJ. = .95 PROJ. SOURCE PROJ. SOURCE PROJ. SOURCE PROJ. SOURCE PROJ. SOURCE -------------------------------------------------------------------------------- 1.0000 N001 1.0000 N007 1.0000 N010 1.0000 N013 1.0000 N050 1.0000 N055 1.0000 N067 1.0000 N074 1.0000 N082 1.0000 N084 1.0000 N124 -------------------------------------------------------------------------------- ESTIMABLE LINEAR COMBINATIONS OF INESTIMABLE SOURCES COEFF. SOURCE COEFF. SOURCE COEFF. SOURCE COEFF. SOURCE SCE STD ERR -------------------------------------------------------------------------------- --------------------------------------------------------------------------------

  14. Step 3. Outputs and Diagnostics(Continued)

  15. Ambient Concentrations SPECIES CONCENTRATIONS - SITE: WELBY DATE: 01/17/97 CMB 8.0 SAMPLE DURATION 6 START HOUR 06 SIZE: F R SQUARE .92 PERCENT MASS 92.9 CHI SQUARE .61 DF 71 SPECIES-------I---MEAS------------------CALC-------------RATIO C/M----RATIO R/U MSGC MSGU 53.08030+- 2.70112 49.30879+- 2.75460 .93+- .07 -1.0 CLIC CLIU .45540+- .05500 .16968+- .14611 .37+- .32 -1.8 N3IC N3IU * 10.48780+- .69455 10.67327+- 1.06226 1.02+- .12 .1 S4IC S4IU * 5.03660+- .39970 5.09780+- .50206 1.01+- .13 .1 N4CC N4CU * 5.04460+- .26760 4.96042+- .37563 .98+- .09 -.2 KPAC KPAU * .06260+- .00540 .02144+- .10408 .34+- 1.66 -.4 TCTC TCTU 21.55080+- 1.38265 21.47490+- .56656 1.00+- .07 -.1 OCTC OCTU * 13.42380+- 1.14530 13.44489+- .85198 1.00+- .11 .0 ECTC ECTU * 8.12700+- .77460 8.03003+- .93283 .99+- .15 -.1 NAXC NAXU * .07980+- .04150 .10208+- .09784 1.28+- 1.39 .2 MGXC MGXU * .01450< .04340 .04659< .06822 3.21< 10.71 .4 ALXC ALXU * .13630+- .01320 .31693+- .18586 2.33+- 1.38 1.0 SIXC SIXU * .52050+- .02830 1.01873+- .45401 1.96+- .88 1.1 PHXC PHXU * .00000< .01640 .00782< .06720 .00< .00 .1 SUXC SUXU 2.05200+- .10310 1.74534+- .16945 .85+- .09 -1.5 CLXC CLXU * .34080+- .02290 .18274+- .13900 .54+- .41 -1.1 KPXC KPXU * .12110+- .00820 .14971+- .06074 1.24+- .51 .5 CAXC CAXU * .21120+- .01240 .16502+- .09707 .78+- .46 -.5

  16. MPIN Matrix TRANSPOSE OF SENSITIVITY MATRIX FOR SITE: WELBY DATE: 01/17/97 DURATION: 6 , START HOUR: 06, SIZE: F SPECIES NVNSP NVNSP2 NVSM NWHD NMc NWFSc NWSHc2 NRDC AMSUL AMNIT PCHCLC N3IU .00 .00 .01 .00 .00 .00 .00 -.03 -.26 1.00 .04 S4IU .00 .00 .01 .00 .00 .00 .00 -.02 1.00 -.33 .03 N4CU .00 .00 -.01 .00 .00 .00 .00 .04 .33 .63 -.05 OCTU -.26 -.40 .97 .01 .03 -.01 .01 -.01 .00 .00 .00 ECTU .06 -.08 -.04 1.00 -.18 -.02 .01 -.03 -.01 .00 .00 NAXU .00 .02 -.03 .02 .00 .00 -.01 .43 .02 -.01 -.15 MGXU -.02 .04 .00 .03 -.01 .00 .00 .25 .01 .00 -.09 ALXU .00 .01 -.02 -.01 .00 .01 -.01 .46 -.03 .01 .13 SIXU .00 .01 -.02 .01 -.02 .01 -.02 .87 .01 -.01 -.13 KPXU .02 .04 -.14 -.01 .04 -.03 .07 1.00 .04 -.01 -.28 PHENAN .40 .27 -.32 -.16 .12 -.07 .06 -.01 .00 .00 .00 FLUORE 1.00 -1.00 -.22 -.36 .03 -.03 -.04 .00 .00 .00 -.01 A_MFLU .42 -.31 .12 -.18 -.11 .01 -.07 -.01 .00 .00 .00 M_1FLU .33 -.19 .05 -.13 -.08 -.01 -.02 -.01 .00 .00 .00 B_MFLU .17 -.12 .10 -.07 -.08 .00 -.02 -.01 .00 .00 .00 C_MFLU -.27 .87 .17 .06 -.08 .00 .01 -.02 .00 .00 .00 A_MPHT -.10 .72 -.01 .02 .00 .00 -.01 -.01 .00 .00 .00 RETENE -.01 -.01 .02 -.01 .00 .17 -.06 .00 .00 .00 .00 GNONLA .18 .43 -1.00 .01 1.00 .00 -.04 -.05 .00 .00 .02 F4GUCL .31 -.38 -.11 -.12 .04 .42 -.07 .00 .00 .00 .00 M4SYRG -.03 .20 -.47 .05 -.05 -.78 1.00 -.08 -.01 .00 .03 E4SYRG -.02 .09 -.21 .02 -.03 -.32 .46 -.04 -.01 .00 .01 ISOEUG -.06 .00 -.01 -.04 -.01 1.00 -.11 .00 .00 .00 .00

  17. Species Source Contributions SOURCE CONTRIBUTIONS (UG/M3) FOR SITE: WELBY DATE: 01/17/97 DURATION: 6 , START HOUR: 06, SIZE: F CALC SPECIES(PER SOURCE) INDIVIDUAL RATIO = -------------------------- MEAS SPECIES(ALL SOURCES) SPECIES NVNSP NVNSP2 NVSM NWHD NMc NWFSc NWSHc2 NRDC AMSUL AMNIT PCHCLC MSGU .063 .017 .124 .136 .035 .015 .046 .104 .128 .258 .001 CLIU .002 .003 .004 .007 .002 .002 .007 .346 .000 .000 .000 N3IU .001 .000 .002 .001 .000 .000 .000 .002 .000 1.012 .000 S4IU .002 .002 .003 .006 .000 .000 .003 .010 .984 .000 .001 N4CU .000 .000 .000 .000 .000 .000 .001 .001 .369 .612 .000 KPAU .000 .000 .000 .000 .062 .045 .147 .088 .000 .000 .001 TCTU .136 .035 .255 .315 .086 .036 .107 .026 .000 .000 .000 OCTU .114 .039 .379 .102 .135 .037 .157 .039 .000 .000 .000 ECTU .174 .029 .051 .666 .005 .034 .025 .005 .000 .000 .000 NAXU .023 .020 .000 .127 .015 .002 .014 1.078 .000 .000 .000 MGXU .000 .112 .000 .439 .001 .006 .013 2.642 .000 .000 .000 ALXU .017 .017 .000 .021 .002 .001 .000 2.249 .000 .000 .019 SIXU .016 .014 .000 .071 .001 .001 .000 1.847 .000 .000 .007 SUXU .006 .003 .008 .010 .001 .000 .003 .012 .807 .000 .001 CLXU .005 .006 .009 .014 .005 .002 .007 .487 .000 .000 .000 KPXU .004 .004 .013 .004 .029 .024 .103 1.054 .000 .000 .002 CAXU .015 .017 .049 .020 .000 .000 .000 .672 .000 .000 .007

  18. Step 4. Evaluate Model Assumptions • Source compositions constant • Chemical species add linearly • All contributing sources included • Source profiles linearly independent • Number of sources less than number of species • Measurement uncertainties random, uncorrelated, and normally distributed

  19. Step 5. Adjust Model Inputs • Increase uncertainties of profiles or provide different composites • Linearize profiles with chemical theory • Identify and characterize missing sources • Measure additional species at source and receptor. • Stratify samples by meteorological regime • Test for effect of deviation with randomized data from non-normal distributions

  20. Step 6. Verify Consistency and Stability • Substitute different profiles for the same source type • Add or drop species • Examine source contributions to species • Examine modified psuedo inverse matrix

  21. Step 7. Evaluate and Reconcile • Compare source contributions among nearby sites • Compare source contribution variations over time with expected emissions and meteorological variations • Apply other receptor methods and compare results • Apply dispersion models and compare results

  22. Protocol for Reconciling Differences AmongReceptor and Dispersion Models 1. Compare CMB and DM results 2. Verify input data in both models 3. Recompare results 4. Refine CMB model inputs 5. Recompare result. 6. Refine dispersion model inputs 7. Recompare 8. “… if it is clearly evident that the dispersion model is not valid, the CMB estimates should be used as the basis for control strategy development. However, if the disparity is not clearly attributable to either model alone, the dispersion model should be used for control strategy development.”

  23. Conclusions • The applications and validation protocol results in more accurate source apportionments • Though the protocol does not solve every problem encountered in the CMB, it does identify that a problem exists and suggests some alternatives for solving it • Reconciliation of CMB source apportionments with other source apportionment methods yields more accurate results

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