November 15, 2006CRPAQS TC Meeting1 Photochemical Modeling Investigation of an Extended Winter PM Episode in Central California 1. Air Resources Board, California Environmental Protection Agency 2. Department of Land, Air, and Water Resources, University of California at 2 Davis 3. Department of Mechanical and Aeronautical Engineering, Univ. California at Davis 4. Department of Civil and Environmental Engineering, University of California at Davis # Now at Sibley School of Mechanical and Aerospace Engineering, Cornell University Jinyou Liang 1, Ajith Kaduwela 1,2, K. Max Zhang 3,#, Qi Ying 1, Michael Kleeman 4, and Anthony Wexler 2,3,4

November 15, 2006CRPAQS TC Meeting2 Modeling Approach Use data from California Regional PM10/PM2.5 Air Quality Study (CRPAQS) – MM5 meteorology with FDDA (NWS data) ARB/UC Davis emissions inventory Several AQ modeling approaches –CMAQ (with ARB modifications) –CMAQ-UCD –CMAQ-MADRID –CIT/UCD

November 15, 2006CRPAQS TC Meeting3 Meteorology Model Performance MBMGE Wind speed (ms -1 )0.49 (0.5)1.53 (0.5) Wind direction (º)3.54 (10)57.21 (30) Temperature (K)0.76 (0.5)2.5 (2)

November 15, 2006CRPAQS TC Meeting4

November 15, 2006CRPAQS TC Meeting5

November 15, 2006CRPAQS TC Meeting6

November 15, 2006CRPAQS TC Meeting7

November 15, 2006CRPAQS TC Meeting8 ARB CMAQ Model Setup 4 km 2 horizontal grid (185x185) with 15 vertical layers up to 15 km Internal mixture, modal approach, SAPRC99_ae3_aq Some code modifications ~22-day run on 16-CPU Linux cluster in ~2 days

November 15, 2006CRPAQS TC Meeting9 PM 2.5 Mass Grid Cell Best Match within 49 Cells 49-Cell Average

November 15, 2006CRPAQS TC Meeting10 PM Mass and Key Components mFEmFBR n=0n=3n=0n=3n=0n=3 NH NO SO 4 = TC PM PM

November 15, 2006CRPAQS TC Meeting11 Inorganic Gas Species mFEmFBR n=0n=3n=0n=3n=0n=3 CO HNO NH NO NO O3O SO

November 15, 2006CRPAQS TC Meeting12 Organic Gas Species mFEmFBR n=0n=3n=0n=3n=0n=3 ALK ALK ALK ALK ALK ARO ARO OLE OLE TERP

November 15, 2006CRPAQS TC Meeting13 Individual Components – Domain

November 15, 2006CRPAQS TC Meeting14 Individual Components – FRS

November 15, 2006CRPAQS TC Meeting15 Nitrate at Fresno

November 15, 2006CRPAQS TC Meeting16 Individual Components – ANGI

November 15, 2006CRPAQS TC Meeting17 Nitrate at Angiola

November 15, 2006CRPAQS TC Meeting18 Individual Components – BAK

November 15, 2006CRPAQS TC Meeting19 Nitrate at Bakersfield

November 15, 2006CRPAQS TC Meeting20 24-Hour PM Bakersfield

November 15, 2006CRPAQS TC Meeting21 Control Strategy The dominant component of PM 2.5 was NH 4 NO 3 During this episode, NH 4 NO 3 was –most sensitive to NO x controls –less sensitive to anthropogenic VOC controls –least sensitive to NH 3 controls Carbonatious matter, which was dominant where wood burning was prevalent, was mostly primary Sulfate was not a major component

November 15, 2006CRPAQS TC Meeting22 Next Steps Improvements to emissions Improved methods for meteorological modeling Improvements to chemical mechanisms Evaluation of aloft model performance Mass conservation/consistency in meteorology and air quality models and related issues Modeling of an entire year or longer Use of satellite products for model inputs and evaluation Corroboration of modeled results

November 15, 2006CRPAQS TC Meeting23 Acknowledgments We thank –Kemal Gürer for generating episodic meteorology fields using MM5 –Kasia Turkiewicz for her assistance in understanding and utilizing the observational data –Paul Allen for his development of long-term emissions inventories

November 15, 2006CRPAQS TC Meeting24 DISCLAIMER The contents of this presentation does not necessarily reflect the views and policies of the California Air Resources Board, nor does mention of trade names or commercial products constitute endorsement or recommendation for use.

November 15, 2006CRPAQS TC Meeting25 International Conference on Atmospheric Chemical Mechanisms December 6-8, 2006, just before the AGU meeting in San Francisco (with events planned for the weekend) Held at University of California, Davis Impressive list of U.S. and international invited speakers Information and registration at ConfHome.cfm?confid=264 ConfHome.cfm?confid=264