1. October 1-3, 20076 th Annual CMAS Meeting1 Effects of Liquid Water on Secondary Inorganic Aerosol in Central California During a Winter Episode 1 Planning and Technical Support Division Air Resources Board California Environmental Protection Agency 2 Department of Land, Air and Water Resources University of California at Davis Paul Livingstone 1, Ajith Kaduwela 1,2, Kemal Gurer 1, Paul Allen 1, and Bruce Jackson 1

2. October 1-3, 20076 th Annual CMAS Meeting2 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.

3. October 1-3, 20076 th Annual CMAS Meeting3 Outline Introduction Modeling Approach Results and Discussions –Liquid Water from MM5 –Simulated SIA –Effects of Cloud and Rain Summary

4. October 1-3, 20076 th Annual CMAS Meeting4 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, O 3 –Large: soluble, H 2 O 2, HCHO, SO 2, Sulfate ion –SIA (Ammonium ion, nitrate ion, sulfate ion)

5. October 1-3, 20076 th Annual CMAS Meeting5 The San Joaquin Valley 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)

6. October 1-3, 20076 th Annual CMAS Meeting6 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 PM 2.5 and PM 15 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 O 3 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 PM 2.5 and PM 10 seasonal) Summer 1990: San Joaquin Valley Air Quality Study/Atmospheric Utilities Signatures Predictions and Experiments (SJVAQS/AUSPEX, first central California regional study of O 3 and PM 2.5 ) – 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) Prof. John Watson, DRI

7. October 1-3, 20076 th Annual CMAS Meeting7 Seasonality of O 3 and PM 2.5 Fresno – 1 st Street

8. October 1-3, 20076 th Annual CMAS Meeting8 Measurements 162 Air Quality Stations 365 Meteorology Stations

9. October 1-3, 20076 th Annual CMAS Meeting9 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

10. October 1-3, 20076 th Annual CMAS Meeting10 Observed RH DayNight

11. October 1-3, 20076 th Annual CMAS Meeting11 Cloud Water from MM5 DayNight Column 400 m AGL

12. October 1-3, 20076 th Annual CMAS Meeting12 Rainwater from MM5 DayNight Column 400 m AGL

13. October 1-3, 20076 th Annual CMAS Meeting13 Rain+Cloud Water from MM5 DayNight

14. October 1-3, 20076 th Annual CMAS Meeting14 Simulated SIA DayNight

15. October 1-3, 20076 th Annual CMAS Meeting15 Simulated SO 2 DayNight

16. October 1-3, 20076 th Annual CMAS Meeting16 ∆SO 2 and ∆SIA – Effect of LW Day Night SO 2 SIA

17. October 1-3, 20076 th Annual CMAS Meeting17 ∆SO 2 and ∆SIA – Constrained LW Day Night SO 2 SIA

18. October 1-3, 20076 th Annual CMAS Meeting18 ∆SO 2 and ∆SIA – Constrained LW Day Night SO 2 SIA

19. October 1-3, 20076 th Annual CMAS Meeting19 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

20. October 1-3, 20076 th Annual CMAS Meeting20 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 5 th – Friday, December 7 th, 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/http://airquality.ucdavis.edu/