1 Planning and Technical Support Division Air Resources Board

1. Effects of Liquid Water on Secondary Inorganic Aerosol in Central California During a Winter Episode 1Planning and Technical Support Division Air Resources Board California Environmental Protection Agency 2Department of Land, Air and Water Resources University of California at Davis Paul Livingstone1, Ajith Kaduwela1,2, Kemal Gurer1, Paul Allen1, and Bruce Jackson1 6th Annual CMAS Meeting

2. DISCLAIMER The content 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. 6th Annual CMAS Meeting

3. Outline • Introduction • Modeling Approach • Results and Discussions • Liquid Water from MM5 • Simulated SIA • Effects of Cloud and Rain • Summary 6th Annual CMAS Meeting

4. Introduction • Meteorological Parameters • Drive the distribution of tracers in the air • Used in key components of CMAQ • Atmospheric Liquid Water • Medium for aqueous-phase reactions • Absorption, evaporation, deposition • Effects of Liquid Water • Visible and invisible • Small: insoluble gases, O3 • Large: soluble, H2O2, HCHO, SO2, Sulfate ion • SIA (Ammonium ion, nitrate ion, sulfate ion) 6th Annual CMAS Meeting

5. One of the most productive agricultural regions in the world – Cadillac Dessert Major goods movement corridors Oil production in the southern Valley Air Quality: Second most polluted area in the US and second most studied area in the world Ozone pollution in the summer and PM pollution in the winter (but the annual PM standard is more restrictive) The San Joaquin Valley 6th Annual CMAS Meeting

6. Prof. John Watson, DRI Major field studies • 1970: Project Lo-Jet (identified summertime low-level jet and Fresno eddy) • 1972: Aerosol Characterization Experiment (ACHEX, first TSP chemical composition and size distributions) • 1979-1980: Inhalable Particulate Network (first long-term PM2.5 and PM15 mass and elemental measurements in Bay Area, Five Points) • 1978: Central California Aerosol and Meteorological Study (seasonal TSP elemental composition, seasonal transport patterns) • 1979-1982: Westside Operators (first TSP sulfate and nitrate compositions in western Kern County) • 1984: Southern SJV ozone study (first major characterization of O3 and meteorology in Kern County) • 1986-1988: California Source Characterization Study (quantified chemical composition of source emissions) • 1988-89: Valley Air Quality Study (first spatially diverse, chemical characterized, annual and 24-hour PM2.5 and PM10 seasonal) • Summer 1990: San Joaquin Valley Air Quality Study/Atmospheric Utilities Signatures Predictions and Experiments (SJVAQS/AUSPEX, first central California regional study of O3 and PM2.5) – Also known as SARMAP (SJVAQS/AUSPEX Regional Modeling Adaptation Project) • Winter 1995: CRPAQS Pilot Study (IMS95, first sub-regional winter study) • December 1999 to February 2001: CRPAQS and CCOS (first year-long, regional-scale effort) • December 1999 to present: Fresno Supersite (first multi-year experiment with advanced monitoring technology) 6th Annual CMAS Meeting

7. Seasonality of O3 and PM2.5 Fresno – 1st Street 6th Annual CMAS Meeting

8. Measurements 162 Air Quality Stations 365 Meteorology Stations 6th Annual CMAS Meeting

9. Modeling Approach • Episode: • December 25-30, 2000 • Spin-up: December 22-24, 2000 • Meteorological inputs • MM5 with FDDA (NWS data) • MM5 with ‘observed’ liquid water • radiation fog within PBL, MM5 cloud above • observed RH at stations and nearby grids • no rain • MM5 with invisible liquid water only • CARB 2002 emissions inventory back-casted to 2000 (but not the inventory used in recent SIPs) • CMAQ with SAPRC-99 chemistry and ‘ae4’ aerosol module 6th Annual CMAS Meeting

10. Observed RH Day Night 6th Annual CMAS Meeting

11. Cloud Water from MM5 Day Night Column 400 m AGL 6th Annual CMAS Meeting

12. Rainwater from MM5 Day Night Column 400 m AGL 6th Annual CMAS Meeting

13. Rain+Cloud Water from MM5 Day Night 6th Annual CMAS Meeting

14. Simulated SIA Day Night 6th Annual CMAS Meeting

15. Simulated SO2 Day Night 6th Annual CMAS Meeting

16. ∆SO2 and ∆SIA – Effect of LW Day Night SO2 SIA 6th Annual CMAS Meeting

17. ∆SO2 and ∆SIA – Constrained LW Day Night SO2 SIA 6th Annual CMAS Meeting

18. ∆SO2 and ∆SIA – Constrained LW Day Night SO2 SIA 6th Annual CMAS Meeting

19. Summary • CMAQ was used to evaluate the effects of clouds and rain on SIA in San Joaquin Valley during December 25-30, 2000 • MM5 produced more liquid water than observed • The impact of total water on SIA is significant, but that of rain+cloud is less significant. The importance decreased as the episode progressed 6th Annual CMAS Meeting

20. International Aerosol Modeling Algorithms (I AM A) Conference • Bi-annual in-depth look at the inner-workings of aerosol models (complements the annual CMAS Meeting) • Wednesday, December 5th – Friday, December 7th, 2007 (just before the AGU meeting in San Francisco) • University of California at Davis • Impressive list of U.S. and international invited speakers • Information at http://airquality.ucdavis.edu/ 6th Annual CMAS Meeting