1. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division 26 October 2011 Diagnostic Evaluation of Carbon Sources in CMAQ Sergey L. Napelenok 1, Heather Simon 1, Prakash V. Bhave 1, George A. Pouliot 1, Michael Lewandowski 1, Rebecca Sheesley 2 1 U.S. Environmental Protection Agency Research Triangle Park, NC 2 Baylor University Waco, Texas 10 th Annual CMAS Conference Chapel Hill, NC

2. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division 1 Sites of interest: Bondville, IL; Northbrook, IL; Detroit, MI; Cincinnati, OH Modeling episode: March 2004 – February 2005

3. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division 2 Traditional Model Evaluation for Particulate Carbon Routine monitoring networks measure only TEC and TOC. For these 4 sites, such evaluation is consistent with previous studies. Four cases to explore: Summer bias = -1.7 μg/m 3 Northbrook winter bias = -1.4 μg/m 3 Detroit spring bias = -0.3 μg/m 3 Non-Detroit spring bias = -1.0 μg/m 3 Diagnosing the causes of model bias with only this data is difficult.

4. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division 3 More Detailed Measurements Over 80 particle-phase organic compounds measured from March 2004 to February 2005 at the four Midwestern sites. Filter samples collected every 6 th day Filter extracts were composited on a monthly basis and analyzed by chemical derivitization and gas chromatography - mass spectrometry (GC-MS) for individual organic compounds. –Hentriacontane, 20R-aaa-cholestane, Fluoranthene, levoglucosan, etc. Composites were also analyzed by EPA scientists for highly polar compounds, which are tracers for SOA species. –Pinonic acid, 2-methylthreitol, caryophyllinic acid, etc. Lewandowski, et al, Primary and Secondary Contributions to Ambient PM in the Midwestern United States, Environ. Sci. Technol., 2008, 42, 3003- 3309.

5. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division 4 POA 1 POA 2 POA 3 POA 4 POA 5 POA 6 POA 7 POA 8 POA 9 POA 10 POA 11 POA 12 POA 13 POA 14 POA 15 POA 16 Organic PM 2.5 Non-volatile EMISSIONS monoterpene BIOGENIC EMISSIONS SV_TRP1 SV_TRP2 O 3 P, NO 3 ∙OH,O 3 ATRP1, ATRP2 Pathways do not contribute to SOA SV_ISO1, SV_ISO2 SV_SQT O 3,O 3 P, or NO 3 ∙OH ∙OH,O 3, or NO 3 isoprene sesquiterpenes ASQT AISO1, AISO2 AISO3 H+H+ high-yield aromatics long alkanes ANTHROPOGENIC EMISSIONS low-yield aromatics benzene ATOL1, ATOL2 AXYL1, AXYL2 SV_TOL1 SV_TOL2 ∙OH/NO SV_XYL1 SV_XYL2 ∙OH/NO AALK SV_ALK ∙OH ABNZ1, ABNZ2 SV_BNZ1 SV_BNZ2 ∙OH/NO AXYL3 ATOL3 ABNZ3 ∙OH/HO 2 AOLGB AOLGA AORGC ∙OH dissolution cloud water glyoxal methylglyoxal VOCs EMISSIONS More Detailed Model (CMAQ v4.7.1 – Similar results expected with CMAQv5.0) POA Tagged 16 different source categories of EC and OC. – Onroad Diesel Exhaust– Coal Combustion – Nonroad Diesel Exhaust– Oil Combustion – Onroad Gasoline Exhaust– Natural Gas Combustion – Nonroad Gasoline Exhaust – Food Cooking – Aircraft Exhaust – Paved Road Dust – Anthrop Biomass Combustion – Crustal Material – Wildfires – Misc. Industrial Processes – Waste Combustion– Other

6. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division PM Carbon Eastern U.S. Emissions Summary 5

7. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division 6 Example of Source Specific Emissions – January 1, 2005 onroad dieseloil combustion

8. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division Converting Source Tagged Species to Organic Tracers 7

9. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division Mobile Sources 8

10. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division 9 Mobile Sources – Hopanes & Steranes Calculating change in bias from sector correction: RatioConc Δbias μg/m 3 1.0.820.330.07 2.0.720.190.07 3.0.760.290.09 4.0.490.160.17 0.07 0.17 0.09 0.07

11. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division Biomass Burning - Levoglucosan 10 0.38 0.08 -0.07 0.32

12. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division Natural Gas Combustion - Ketones 11 -0.04 -0.19 -0.01

13. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division Organic Aerosol 12 POC compares reasonably well to measurements. SOA is underestimated for all species. Comparison in the Midwest is worse than previous evaluation with tracer data in Research Triangle Park.

14. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division 13 Monoterpenes Midwest – 2004/2005RTP – 2003

15. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division 14 Aromatics Midwest – 2004/2005RTP – 2003

16. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division Potential Gains From Improvements – Organic Aerosol Isoprenes  0.680.000.050.22  Evidence for missing aqueous chemistry pathways Monoterpenes  0.310.030.170.13  Needs further analysis and data is available at other sites Sesquiterpenes  0.130.200.240.09  Evidence for emissions problems  Aromatics  0.170.040.150.09  Potentially increase the yields 15

17. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division Concluding Remarks Unique comparison on model performance for an annual tracer dataset Measured tracer compounds are not inert – some react, degrade, and/or have secondary sources in the atmosphere Measurement uncertainty is ~ 30% A valuable dataset for diagnostic evaluation: 16 Source Summer Gain (μgC/m 3 ) Northbrook Winter Gain (μgC/m 3 ) Detroit Spring Gain (μgC/m 3 ) Non-Detroit Spring Gain (μgC/m 3 ) SOA1.290.270.610.53 Biomass Burning0.380.32-0.070.08 Mobile0.07 0.090.17 Natural Gas-0.04-0.01-0.19-0.01 “Unexplained”0.00!!0.75-0.140.23

18. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division 17 contact: napelenok.sergey@epa.gov

19. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division Additional Material… 18

20. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division 19 Model Description CMAQ v4.7.1 –SAPRC99 Chemistry –12km horizontal Eastern US domain nested within 36km continental domain –24 vertical layers up to 100 mb. –MM5 meteorology –SMOKE emissions (special treatment for primary TC) –Hourly Geos-Chem boundary conditions Track source specific primary carbon concentrations using the Carbon Apportionment option

21. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division 20

22. Office of Research and Development National Exposure Research Laboratory, Atmospheric Modeling and Analysis Division 21 Summary/Conclusions Comparisons of measured and modeled tracers for primary sources are reasonable considering the uncertainty range of the observations (30%). Hopanes and Steranes show the best comparison. Levoglucosan is under predicted by the model in the summer indicating a possible missing source (wild fires in Canada?) Tracers with high model/obs ratios are known to degrade in the atmosphere (decay process not implemented in the model) e.g. hopanes at the rural site Bondville. Higher model/obs ratios in the summer support the possibility of tracer volatilization and degradation. Tracers with low model/obs ratios are known to have secondary source in the atmopshere e.g. n-Alkanoic Acids.