Regional Modeling Update September 12, 2002 Air Resources Board California Environmental Protection Agency Ajith Kaduwela, Ph.D Luis F. Woodhouse, Ph.D.

Collaborators Emissions –Paul Allen, P.E. –Emissions Inventory Branch Meteorology –Shuming Du, Ph.D. –Kemal Gurer, Ph.D. –Daniel Chau, Ph.D Air Quality –Luis Woodhouse, Ph.D. –Jinyou Liang, Ph.D. Chemistry –Bruce Jackson, M.S.

Outline Summary of Draft Modeling Protocol Photochemical Models Used Model Input Preparation Meteorological Models Used Modeling Results/Performance Evaluation MATES-II, CRC/DOE/NERL Study Future Work

Summary of Modeling Protocol Modeling Approach: –Apply air quality models to assess health impacts from direct inhalation at both micro and regional scale. –Micro-scale modeling for near source impacts –Regional scale to simulate transport of pollutants from all emission sources in Southern California

Modeling Protocol (cont.) Simulate air quality from January 1 to December 31, 1998 Modeling Domain –87 x 67 cells –4 x 4 km 2 grid size

Regional Modeling Domain San Diego Riverside Los Angeles San Bernardino Ventura Orange Mexico

Modeling Protocol (cont.) Emissions –Seasonal weekend and weekday inventories instead of monthly –Total of 8 emission inventories Chemical Mechanism –SAPRC-99 –Modified to include additional toxics

Toxics –1,3-butadiene –Formaldehyde –Acetaldehyde –Acrolein –Benzene –Carbon tetrachloride –Chloroform –Dichloromethane –1,2-Dichloroethane –o-Dichlorobenzene –p-Dichlorobenzene –Ethylene oxide –Styrene –Toluene –Trichloroethylene –Vinyl Chloride –Xylenes –Diesel PM10 –Arsenic –Beryllium –Cadmium –Hexavalent Chromium –Iron –Lead –Manganese –Mercury –Nickel –Zinc

Modeling Protocol (cont.) Two grid-base photochemical models –Run Models-3/CMAQ for selected episodes –Run one air quality model for entire 1998 using CALGRID instead of UAM-FCM

Air Quality Model Change Why not UAM-FCM? –Based on older version of UAM (UAM-IV) –No longer supported –Chemical solver difficulties Why CALGRID? –Better formulation than UAM-IV –Better documentation –Flexible chemical mechanism

CALGRID Grid-based photochemical model developed in 1989 for ARB and last updated in 2000 (Version 1.6b) Choice of chemical mechanisms (CB4 or SAPRC) ARB’s implementation of a flexible chemical mechanism interface

Community Multiscale Air Quality Modeling System Models-3/CMAQ Photochemical air quality model first released in 1999 with EPA funding. State-of-the-Science but limited use to date Continually under development Aqueous-phase chemistry, aerosol dynamics and modal size distributions, aerosol deposition, plume chemistry, and process analysis

CMAQ vs. CALGRID CMAQ –MM5 –17 vertical layers –Domain top: 14.6 km –SAPRC-99 with toxics SMVGEAR –QSSA or SMVGEAR –dry deposition for some toxic VOCs –first order decay for deposition of PM –7 days of CPU/month –1 GB/day CALGRID –CALMET –10 vertical layers –Domain top: 3 km –SAPRC-99 with toxics Hybrid –QSSA or Hybrid –dry deposition for all toxic VOCs –particulate deposition for PM –3 days of CPU/month –0.5 GB/day

Model Input Preparation Initial and Boundary Conditions Emissions Meteorology

Initial and Boundary Conditions Initial and Boundary conditions same for each month –Boundary conditions same as for SCOS-97 EPA Clean over ocean (40 ppb O3, ppb NOx, and 20 ppbC VOC) South Coast clean over land (40 ppb O3, 2 ppb NOx, 60 ppbC VOC) MATES-II 40 ppb O3, 1.5 ppb NOx, 30 ppbC VOC

Emissions Based on inventories developed for SCOS- 97, adjusted to 1998 Weekend and weekday inventories by season Using latest profiles, and surrogates to spatially allocate emissions Use latest version of EMFAC2000 for motor vehicle inventory with DTIM4

Weekend and Weekday Area Source Emissions Winter and Summer 1998 tons/day

Weekend and Weekday Elevated Emissions tons/day

Levels (kg/hr): 1 (B) 10 (G) 50 (Y) 80 (O) 100 (R) Levels (kg/hr): 1 (B) 10 (G) 50 (Y) 80 (O) 100 (R) 0 hr 6 hr 12 hr 16 hr Summer Weekday NO

Levels (kg/hr); 1 (B) 2 (G) 3 (Y) 4 (O) 5 (R) Levels (kg/hr); 1 (B) 2 (G) 3 (Y) 4 (O) 5 (R) 0 hr 6 hr 12 hr 16 hr Summer Weekday BENZENE

Levels (kg/hr): 1 (B) 3 (G) 4 (Y) 5 (O) 6 (R) Levels (kg/hr): 1 (B) 3 (G) 4 (Y) 5 (O) 6 (R) 0 hr 6 hr 12 hr 16 hr Summer Weekday DIESEL PM10

Meteorology Models require hourly meteorological data for each grid in domain Models needed to create gridded meteorological fields –Prognostic: predicts from first principles, mass and energy transfer equations (MM5) –Diagnostic: uses observational data (CALMET)

NCAR/Penn State Mesoscale Model (MM5) Advanced state-of-the-science prognostic regional model –solves conservation equations to predict winds and temperatures –requires initial conditions, and boundary conditions for each hour simulated Applied with one coarse and one nested domain

MM5 (cont.) Analysis nudging used but no Data assimilation (FDDA) 27 vertical layers (matched to 17 for air quality simulations) MM5 exercised for entire 1998

CALMET Diagnostic generation of meteorological fields with objective analysis Parameterized treatments of slope flows, kinematic terrain effects, terrain blocking effects, and a micro meteorological model for overland and overwater boundary layers

CALMET (cont.) Model driven by observations –10 National Weather Service surface sites –~100 California Irrigation Management System (CIMIS) surface stations –One upper air (NWS) site and two buoys –~60 surface ARB/District monitoring sites (for January and August only)

Model Output Example: August 5, 12:00hrs MM5 CALMET

Model Output Example: January 20, 12:00hrs MM5 CALMET

Model Performance Evaluation Process of establishing that an air quality model is adequately reproducing the chemical and physical processes that generate and transport pollutants (“right answer for the right reason”) Spatial and temporal evaluations needed

Model Performance Evaluation Procedures well established for episodic hourly concentrations of O 3 –peak estimation accuracy, mean bias, variance, gross error, scatter plots, time series plots, and isopleths –diagnostic and sensitivity simulations No procedure established for 24-hr or annual concentrations

Approach: –Hourly evaluation of selected episodes for O 3, NOx, and CO using ARB guidance –Several days to monthly evaluation of O 3, NOx, CO, toxic VOCs (24-hr) and PM components –Annual performance evaluation Model Performance Evaluation (cont.)

Data For Model Evaluation 1-hr average concentrations for all 1998 O 3, NO, CO, NO 2 ARB and District monitoring sites 24-hr Average concentrations for PM10 components 24-hr measurements for selected VOCs

Completed Simulations CMAQ/Models-3 –August 1- 7, 1998 –January 1-31, 1998 –Performance evaluation CALGRID –August 1-7, 1998 – January 1-31, 1998 –Performance evaluation

Domain Peak 1-hr Ozone (ppb) August 2-7, 1998

Peak O3 Aug 14 hrs CALGRIDCALGRID CALGRIDCALGRID CMAQ: AUG 17 hrs CMAQ: AUG 3 at 16 hrs Aug 13 hrs

24-hr Model Performance August 1-7, 1998 Calculated 24-hr monthly average for O3, CO, and NOx (from hourly values) and compare with predictions Insufficient data to fully assess 24-hr model performance for toxics

Ratio of Predicted-to-Observed 24-hr averages for Toxics on August 1-7, 1998

Observed Maximum 1-hr Ozone January 1-31, 1998

CMAQ/Models-3 January 14 hrs January 1998 Predicted Ozone Distribution During Peak CALGRID January 26, 1998 at 16 hrs

24-hr Model Performance January Calculated 24-hr monthly average for O3, CO, and NOx (from hourly values) and compare with predictions Insufficient data to fully assess 24-hr model performance for toxics

Ratio of Predicted-to-Observed 24-hr Averages for Toxics on January, 1998

SUMMARY Prepared inputs for all 1998 for CALGRID and CMAQ/Models-3 Simulated an extended period (January) and part of August with CALGRID and CMAQ/Models-3 24-hr average concentrations: On average both models show similar 24-hr performance (both January and August 1-7)

MATES II Multiple Air Toxics Exposure Study II South Coast Air Quality Management District Monitored ~30 pollutants from April 1, 1998 to March 31, 1999 at 10 sites Air quality modeling for entire MATES II period –UAM with CB-IV and UAM-tox with updated CB-IV CALMET for meteorology Domain –105 x 60 cell (2x2 km 2 ), 5 layers ; region top of 2 km

CRC & DOE/NREL Study –Final report dated June 30, 2000 –CAMx/RTRAC to treat reactive inert species –Simulated MATES II using CB-IV MATES II Mobile source emissions EMFAC7G MATES II Mobile source emissions update to reflect EMFAC2000 Meteorological fields from CALMET 10 MATES-II sites for model performance August 3-7, 1997 (MM5, CB-IV and SAPRC-99)

Future Work January, 2003: –CALGRID for entire year –Models-3/CMAQ for selected periods –Model performance evaluation –Annual averages and potential risks –Contour plots of risk by species and total risk February, 2003: –Draft report