# FINAL 2003 AQMP APPENDIX V

MODELING AND ATTAINMENT DEMONSTRATIONS

AUGUST 2003

### SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT

GOVERNING BOARD
Chair: WILLIAM A. BURKE, Ed.D. Speaker of the Assembly Appointee
Vice Chair: S. ROY WILSON, Ed.D. Supervisor, Fourth District Riverside County Representative

MEMBERS:

FRED AGUIAR Supervisor, Fourth District San Bernardino County Representative

MICHAEL D. ANTONOVICH Supervisor, Fifth District Los Angeles County Representative

HAL BERNSON Councilmember, City of Los Angeles Cities Representative, Los Angeles County, Western Region

JANE W. CARNEY Senate Rules Committee Appointee

WILLIAM CRAYCRAFT Councilmember, City of Mission Viejo Cities Representative, Orange County

BEATRICE LAPISTO-KIRTLEY Councilmember, City of Bradbury Cities Representative, Los Angeles County, Eastern Region

RONALD O. LOVERIDGE Mayor, City of Riverside Cities Representative, Riverside County

LEONARD PAULITZ Councilmember, City of Montclair Cities Representative, San Bernardino County

JAMES SILVA Supervisor, Second District Orange County Representative

CYNTHIA VERDUGO –PERALTA Governor’s Appointee

EXECUTIVE OFFICER
BARRY R. WALLERSTEIN, D.Env.Table of Contents

i 

## CONTRIBUTORS

Elaine Chang, DrPH Deputy Executive Officer Planning, Rule Development and Area Sources

Laki Tisopulos, Ph.D., P.E. Assistant Deputy Executive Officer Planning, Rule Development and Area Sources

Zorik Pirveysian Planning & Rules Manager Planning, Rule Development and Area Sources

Joseph Cassmassi Satoru Mitsutomi Mark Bassett Chris Nelson Julia Lester Mary Woods Bong-Mann Kim Zhang, Xinqiu

Production Faye Thomas

CALIFORNIA AIR RESOURCES BOARD

Robert Fletcher Division Chief Technical Support Division

John DaMassa Branch Chief Cynthia Marvin Branch Chief

Bruce Jackson Sylvia Oey Daniel Chau Joe Calavita Paul Allen Don JohnsonTable of Contents

i 

## Table of Contents

CHAPTER 1 Modeling Overview

Introduction........................................................................................................... V - 1- 1 Modeling Methodol ogy ........................................................................................ V - 1- 2 PM 10 ........................................................................................................... V - 1- 2 Ozone ......................................................................................................... V - 1- 3 Background..................................................................................... V - 1- 3 Preliminary Future Year Simulation............................................... V - 1- 6 Independent Revi ew ....................................................................... V - 1- 7 Meterological Episode Selection .................................................... V - 1- 10 Carbon Monoxide ...................................................................................... V - 1- 11 Document Organiza tion ........................................................................................ V - 1- 12



### CHAPTER 2 Revision to the Federal PM10 Attainment Demonstration Plan and Visibility Assessment

Introduction........................................................................................................... V- 2- 1 Ambient Data Characteriza tion and PTEP ........................................................... V- 2- 2 Annual Average Concen trations................................................................ V- 2- 3 24-Hour Average Concen trations .............................................................. V- 2- 7 Modeling Appro ach .............................................................................................. V- 2- 9 UAMAERO-LT ......................................................................................... V- 2- 11 UAMAERO-LT Model I nputs .................................................................. V- 2- 12 Modeling Domain ........................................................................... V- 2- 13 Boundary, Top and Initial Air Qua lity Concentrations.................. V- 2- 13 Future Boundary, Top and Initial Air Quality Conditions ............. V- 2- 14 Meteorological I nputs..................................................................... V- 2- 14 Rain Days........................................................................................ V- 2- 19 9-Cell Averagin g ............................................................................ V- 2- 20 Linear Rollback For 24-Hour Average Maximum Concentrations........... V- 2- 20 Emissions Invent ory.............................................................................................. V- 2- 21 Emissions Uncertainties............................................................................. V- 2- 22 UAMAERO-LT ......................................................................................... V- 2- 11 Paved Road Du st............................................................................. V- 2- 22 Unpaved Road Du st........................................................................ V- 2- 23 Fugitive Wind Blown Dust............................................................. V- 2- 24 Construction Du st ........................................................................... V- 2- 26 Base-Year Simula tions.......................................................................................... V- 2- 28 PM10 Component Species Performance Evaluation for the PTEP Sites............................................................................................................ V- 2- 29Final 2003 AQMP Appendix V

ii UAMAERO-LT Component Species Model Performance Evaluation..... V- 2- 30 Annual Average SSI Mass Perform ance Evaluation................................. V- 2- 31 1995 UAMAERO-LT Grid-Cell Perform ance Evaluation........................ V- 2- 46 PM2.5 Component Species Performance Evaluation for the PTEP Sites............................................................................................................ V- 2- 47 Future Air Qua lity................................................................................................. V- 2- 47 PM 10 Control Strate gy ............................................................................... V- 2- 48 PM 10 in the Year 2006 ............................................................................... V- 2- 49 Annual PM 10 By Component Species for the PTEP Sites.............. V- 2- 49 Annual PM 10 By Total Mass at the SSI Sites ................................. V- 2- 49 UAMAERO-LT Grid-Level Simulation: 2006 Controlled Emissions........................................................................................ V- 2- 50 2006 UAMAERO-LT Hot Spot Grid Weight of Evidence Analysis .......................................................................................... V- 2- 51 Maximum 24-Hr Average PM 10 ..................................................... V- 2- 56 PM 10 in the Year 2010 ............................................................................... V- 2- 57 Annual PM 10 ................................................................................... V- 2- 57 Maximum 24-Hr Average PM 10 ..................................................... V- 2- 58 PM 2.5 in the Year 2010............................................................................... V- 2- 58 Annual PM 2.5 ................................................................................... V- 2- 58 Maximum 24-Hr Average PM 2.5 .................................................... V- 2- 59 PM 10 in the Year 2010 With Alterna tive Control Opti ons ........................ V- 2- 60 Conclusions (Particul ates) .................................................................................... V- 2- 61 Visibility................................................................................................................ V- 2- 63 Background................................................................................................ V- 2- 63 Visibility Modelin g.................................................................................... V- 2- 63 Prior Visibility Modeli ng Results.............................................................. V- 2- 64 Predicted Future Ai r Quality...................................................................... V- 2- 66 Future Visibility Pr ojections...................................................................... V- 2- 67 Riverside Future Mean Visibilities................................................. V- 2- 67 Future Light Extinction Budgets at Riverside ................................ V- 2- 69 Conclusions (Visib ility)........................................................................................ V- 2- 70



### CHAPTER 3 Revision to the 1997 Ozone Attainment Demonstration Plan Introduction........................................................................................................... V - 3- 1 Model Selection ......................................................................................... V - 3- 2 Federal 1-Hour Ozone Standa rd Requirements......................................... V - 3- 3 California Requirements and Popul ation Exposure................................... V - 3- 3 Emissions Summary.............................................................................................. V - 3- 5 Introduction................................................................................................ V - 3- 5 Historical Baseline Emissions ................................................................... V - 3- 6Table of Contents

iii Future Baseline Em issions......................................................................... V - 3- 7 Future Controlled Em issions ..................................................................... V - 3- 7 Episode Selection.................................................................................................. V - 3- 7 Southern California Ozone Study (SCOS97) ............................................ V - 3- 9 Statistical Episode Ranking ....................................................................... V - 3- 10 Horie Classification ................................................................................... V - 3- 12 Episodes Compared in the 2002 "Mid -Course" Assessment..................... V - 3- 12 Episode Characteri zation ...................................................................................... V - 3- 13 Background................................................................................................ V - 3- 13 Synoptic Setting ......................................................................................... V - 3- 14 Mesoscale Meteor ology............................................................................. V - 3- 15 Air Quality Prof ile ..................................................................................... V - 3- 16 Modeling Methodol ogy ........................................................................................ V - 3- 17 Model Input Prepar ation ............................................................................ V - 3- 18 Modeling Domain ........................................................................... V - 3- 19 Boundary, Top and Initial Air Qua lity Concentrations.................. V - 3- 19 Future Boundary, Top and Initial Air Quality Conditions ............. V - 3- 19 Meteorological Scalars ................................................................... V - 3- 20 Meteorological Mode ls................................................................... V - 3- 21 Temperature Fiel ds ......................................................................... V - 3- 22 Mixing Height Fi elds...................................................................... V - 3- 23 Gridded Wind Fiel ds....................................................................... V - 3- 27 Model Input Evalua tion ............................................................................. V - 3- 29 Temperature Fiel ds ......................................................................... V - 3- 29 Mixing Height Fi elds...................................................................... V - 3- 29 Wind Fields..................................................................................... V - 3- 39 1997 Base-year perfomance Evaluation ............................................................... V - 3- 40 Statistical Evalua tion ................................................................................. V - 3- 41 Graphical Evalua tion ................................................................................. V - 3- 45 Effect of Emissions Uncertainties.............................................................. V - 3- 67 Mid-Course Ozone Air Qua lity Evaluation .......................................................... V - 3- 69 Ozone Air Quality Pr ojections.............................................................................. V - 3- 75 Projection of 2007 Air Quality .................................................................. V - 3- 75 Projection of 2010 Air Quality .................................................................. V - 3- 81 Projection of 8-Hour Average Oz one Air Quality for 2010...................... V – 3-94 Projection of 2010 Air Quality for Alte rnate Emissions Scenarios........... V – 3-95 Sensitivity Simula tions .............................................................................. V – 3-96 Conclusions ........................................................................................................... V – 3-96Final 2003 AQMP Appendix V

iv 

### CHAPTER 4 Revision to the Federal Carbon Monoxide Attainment Demonstration Plan

Introduction........................................................................................................... V – 4- 1 Carbon Monoxide Emi ssions................................................................................ V – 4- 2 Introduction................................................................................................ V – 4- 2 Planning Inventor y..................................................................................... V – 4- 3 VMT Forecast ................................................................................. V – 4- 3 Emissions Projec tion ...................................................................... V – 4- 4 Planning Emissions I nventory ........................................................ V – 4- 5 Modeling Methodol ogy ........................................................................................ V – 4- 6 Introduction................................................................................................ V – 4- 6 Regional Modeling An alysis ..................................................................... V – 4- 7 Episode Selectio n....................................................................................... V – 4- 7 Episode Characteri zation ........................................................................... V – 4- 8 Synoptic Setting .............................................................................. V – 4- 9 Mesoscale Setting ........................................................................... V – 4- 9 Air Quality Settin g.......................................................................... V – 4- 11 Model Selectio n ......................................................................................... V – 4- 12 Meteorological Modeling and Input Fields .................................... V – 4- 12 Trajectory Analys is......................................................................... V – 4- 14 CAMx Initial and Boundary Conditions ........................................ V – 4- 14 Base Year Emi ssions ...................................................................... V – 4- 14 Day-of-Week Diurnal Tra ffic Patterns ........................................... V – 4- 14 Base Year Model Pe rformance....................................................... V – 4- 17 Hot Spot Analys is ...................................................................................... V – 4- 24 Carbon Monoxide Control Strategy...................................................................... V – 4- 26 Contingency Meas ures............................................................................... V – 4- 26 Future Air Quality Pr ojections.............................................................................. V – 4- 27 Introduction................................................................................................ V – 4- 27 Emissions ................................................................................................... V – 4- 28 Modeling Results ....................................................................................... V – 4- 28 CAMx Regional Simu lation ........................................................... V – 4- 28 Linear Rollback of CAMx Si mulation Results ............................... V – 4- 29 CAL3QHC Modeling Re sults.................................................................... V – 4- 31 Conclusi on ............................................................................................................ V – 4- 32

REFERENCES

## CHAPTER 1 MODELING OVERVIEW

Introduction Modeling Methodology Document OrganizationChapter 1 Modeling Overview

V - 1- 1 

### INTRODUCTION
This appendix to the 2003 AQM P provides the details of the modeling attainment demonstrations presented in Chapter V of the main document. The federal Clean Air Act (CAA) sets forth specific criteria to use air quality simulation modeling techniques to estimate future air quality in areas that do not meet the air qua lity standards. The Basin is currently designated nonattainment for PM 10 , ozone, and carbon monoxide. The 2003 modeling attainment demonstrations se rve as an update of the 1997 AQMP ozone, PM 10 and carbon monoxide plans for the South Co ast Air Basin and other portions of the Southeast Desert Modified Nonattainment Ar ea that are under the District’s jurisdiction and were submitted as part of the California SIP. The attainment demonstrations provided in this Plan reflect the updated em issions baseline and future year estimates, new technical information and enhanced ai r quality modeling tec hniques and episodes.
Ozone, PM 10 and carbon monoxide each have specif ic air quality modeling requirements that must be met to provide a satisfactory modeling attainment de monstration. Ozone modeling requires the use of a regional an alysis using an urban scale air quality simulation model. For particulates, requireme nts include the use of receptor models and dispersion models to characterize the current and future dispersion of PM 10 on a species component level. A photochemical grid model is used to project regional future carbon monoxide (CO) air quality and additional “hot-spot” analyses are required to assess impacts at intersections.
The District’s goal is to develop an integrat ed control strategy whic h: 1) ensures that ambient air quality standards for all crite ria pollutants are met by the established deadlines in the CAA; and 2) achieves an e xpeditious rate of reduction towards the state and new federal air quality standards. The overall control strategy is designed so that efforts to achieve the standard for one criteria pollutant do not cause unnecessary deterioration of a nother. Ozone and PM 10 are linked by common precursor emissions and as such the control strategies as well as modeling analyses build upon each other. The District employs a two-step approach to modeling and control strategy development: first assess future PM 10 air quality (to meet the 2006 PM 10 attainment date) then analyze future 1-hour ozone air quality (to meet th e 2010 ozone attainment date). Ozone and PM 10 air quality attainment demonstra tions analyses under the 2003 AQMP are performed in keeping with this two-step mode ling approach. The analyses also consider the future efforts that will be needed to achieve the PM 2.5 and 8-hour average ozone standards as they supplant the current air quality standards.
The control strategy to meet federal and st ate carbon monoxide standa rds is independent of the PM 10 /ozone strategy. As previously stat ed, dispersion modeli ng and “hot spot” analyses are required for the attainment demons tration. Both analyses are performed inFinal 2003 AQMP Appendix V: Modeli ng and Attainment Demonstrations

V- 1 - 2 the 2003 AQMP to update the 1997 Revision of the Carbon Monoxide Attainment Demonstration (CO Plan).
The following sections provide a brief overview of the PM 10 , ozone and carbon monoxide modeling methodologies. In essence, Chapter 1 serves as an addendum to the Modeling Protocol provided as Attachem ent 1 as it updates the current strategy employed in the 2003 AQMP modeling attainment demonstrations. Chapter 2 presents the detailed PM 10 attainment demonstration. Chap ter 3 presents the ozone modeling demonstration and Chapter 4 presen ts the carbon monoxide analysis.



### MODELING METHODOLOGY

PM 10 The 2003 AQMP incorporates two PM 10 modeling methodologies to demonstrate future year attainment of the federal standards. A deterministic modeling approach using the UAMAERO-LT regional model was employed to simulate base-year (1995) and futureyears (2006 and 2010) annual PM 10 . UAMAERO-LT is a modified version of the UAMAERO episodic PM 10 model that has been paramete rized to allow for long-term particulate simulations. UAMAERO-LT co mbines a full gaseous chemistry module with an empirically based aerosol module to simulate secondary particulate formation (nitrate, ammonium, sulfate and organic car bon) and primary species. The model also incorporates a size dependent pa rtioning scheme that segregates particulate in the coarse and fine (PM 2.5 ) fractions. Linear rollback on partic ulate component species is used to demonstrate future year attainment of the 24-hour average federal and state PM 10 standards.

The 1997 PM 10 Plan relied on Chemical Mass Bala nce (CMB) receptor modeling and the primary and secondary particulate si mulation using the UAM-Linear Chemistry (UAM/LC) model. UAMAERO-LT, used in th is Plan combines the desired qualities of the CMB and UAM/LC model with the enhan cements of full gas phased chemistry and size portioning, as discussed above. The 1997 PM 10 Plan was founded on speciated particulate data measured in 1995 through the PM 10 Technical Enhancement Program (PTEP) at six sites (five in the Basin and one at an offshore background location). The modeling attainment demonstration for the 1997 PM 10 Plan was focused on base-year (1995) model performance and future year air quality predictions for the five Basin PTEP sites. While the five sites provide a reasonable picture of the PM 10 gradient observed across the Basin, concerns were rais ed about the representativeness of analysis given the high variability of primary par ticulate emissions from grid-to-grid.
As a consequence, the annual PM 10 attainment demonstration in this plan is based on a deterministic approach with a weight of evid ence demonstration. First, a 1995 base-yearChapter 1 Modeling Overview

V - 1- 3 model simulation is provided for the specia ted particulate components and validated through the PTEP data. This base-year simu lation is then validated from supplemental annual average Hi-Vol Size Selective Inlet (SSI) PM 10 data observed at 18 Basin sites. A grid-cell level analysis of model performan ce is discussed. Th e future year annual PM 10 attainment demonstration is provided fo r the particulate component species and total mass at the PTEP sites, as well as the total mass at the SSI locations. As part of the weight of evidence demonstration, the future year grid-cell level simulation is presented and a “hot spot” analysis of individual cells exceeding the federal st andard concentration of 50.4 μg/m 3 is provided.
Finally, annual and 24-hour average PM 2.5 base and future year si mulations are presented and discussed in light of the soon-to-be-implemented PM 2.5 standard and the future attainment.

Ozone
The CAA requires that ozone nonattain ment areas designated as serious and above use a photochemical grid model to demonstrate attainment. The Urban Airshed Model (UAM) with Carbon Bond IV (CB-IV) gaseous chemistry was selected as the modeling tool used in the 2003 AQMP ozone modeling a ttainment demonstration. UAM is an urban scale, three-dimensional, grid-type, numer ical simulation model. It is designed for computing ozone concentrati ons under short-term, episodic conditions lasting one to three days. UAM simulations have been incorporated as the basis of the Basin ozone modeling attainment demonstrations since th e 1989 AQMP. On the date of the release of the Draft 2003 AQMP, UAM was the phot ochemical model, recommended by the U.S. EPA guidance (40 CFR Part 51, Appe ndix W). On April 15, 2003, the final revisons to Appendix W were published in the Federal Re gister. Revised Appendix W removed UAM as the sole recommended mode l by EPA for ozone analysis, and in its place did not name a successor. Revised Appendix W promotes the use of models employing state-of-the-art advances in science.
Background
In 1999, at the inception of the 2003 AQMP mode ling effort, the Modeling Staffs of the District and California Air Resources Board jointly developed a Modeling Protocol to layout a design for evaluating several meteorological, regional air quality and chemical models using the newly acqui red Southern California Air Quality Study (SCOS97) data set. The Modeling Protocol was distri buted to the SCOS97 Working Groups and Stakeholders. (EPA is a member of the SCOS97 Stakeholders).
The proposed scope of the mode ling effort was extensive. The ultimate goal of joint effort was to accurately si mulate multiple meteorological air quality episodes (meeting EPA’s model performance criteria) with the greatest combination of modeling tools notFinal 2003 AQMP Appendix V: Modeli ng and Attainment Demonstrations

V- 1 - 4 only for the AQMP, but for interbasin pollu tant transport and fu ture 8-hour average ozone impacts. The modeling effort planned to take advantage of upgrades made to the emissions inventory in several areas, most notably, the mobile source categories (on and off-road). In total, seven air quality models , three meteorological model combinations and three chemistry packages, selected through the modeling pr otocol were evaluated to some or full extent. Table 1-1 lists th e different model platforms and chemical mechanisms assessed.

Table 1-1 Air Quality and Meteorological Modeling Platforms and Chemical Mechanisms Evaluated for the 2003 AQMP

Air Quality Models Meteorologica l Models Chemistry Mechanisms

UAM MM5 CB-IV

UAM-FCM CALMET SAPRC99
CALGRID MM5/CALMET (Hybrid) TOX

CAMx
CMAQ
MAQSIP
SAQM

As the modeling efforts began to take shape, the District a nd ARB staff divided the work effort to maximize productivity. The fi rst tasks involved reviewing the SCOS97 meteorological data and mete orological modeling tools. The original timetable was designed to provide worki ng meteorological air quality episodes for a scheduled 2000 draft AQMP. Four SCOS97 meteorological episodes and one mete orological episode from July, 1998 (where a significant porti on of the upper air monitoring network remained in southern California) were id entified as candidates. The August 3-7, 1997 meteorological episode was selected as the primary ozone episode. August 5 th (the Basin's 1997 2 nd maximum ozone day) and August 6 th (an eddy circul ation day with transport to Ventura County, Antelope Valley and the Mojave Desert) were selected as episode simulation days for the analysis. (The UAM simulation was started late on August 3 rd , a Sunday, and as consequence there were concerns about the accuracy of the weekend inventory used on the first day and the impact that the inventory uncertaintyChapter 1 Modeling Overview

V - 1- 5 had on the transition to a wee kday simulation. In addition, since the simulation "rampup" began late in the day on the 3 rd , there were concerns that the initial conditions may have been carried late into the day of the 4 th ).
Extensive review of the meteorologica l data was conducted through the SCOS97 Meteorological Working Group and contracted quality a ssurance programs (NOAA and STI). Further work by ARB emissions sta ff and the SCOS97 Emi ssions Working Group resulted in significant improvements in aircraft, shipping and biogenic emission inventories. Unfortunately, the final mobile source emission inve ntories from the on and off-road models (EMFAC2002 and Off-Road), we re not available until November 2002. Final model validation on the meteorological episodes did not commence until winter of 2002.
Through the course of model developmen t, the progress made and methodologies evaluated were routinely presented to th e Scientific, Technical and Peer Modeling Advisory Group of the AQMP Advisory Comm ittee. In addition, independent peer reviews of the work in progress were conducte d by Dr. Robert Harley of the University of California at Berkeley and Dr. William Ca rter of the University of California at Riverside. The mid-course critique was provided to the ARB and District modeling staffs.
By the time the emissions were frozen, the air quality models and chemistry packages still being considered for use in the ozone m odeling attainment dem onstration reduced to the UAM with CB-IV chemistry, the Califor nia Photochemical Grid Model (CALGRID) using CB-IV and SAPRC99 chemistry, and th e Comprehensive Air Quality Model with Extensions (CAMx), with CB-IV and SAP RC99 chemistry. CALGRID is a regional scale, three dimensional, grid type model that embodies several enhancements in layer structure, advection and di spersion schemes not found in UAM. State-of-the science advances in modeling technology present in CAMx take a dvantage of the direct coupling with the non-hydrostatic MM5 primitive equati on meteorological mode l. The SAPRC99 chemistry reflects the state of the science in chemical mechanisms with its enhanced treatment of reactivity and interaction of additional chemical species. Preliminary results of the model performance evaluati on for the August 1997 episode at the key ozone receptor areas in the Basin indicated th at all five model/chemistry combinations achieved the minimum requirements specified in EPA modeling guidance for use in the attainment demonstration. Specifically , UAM had the best performance overall in simulating the unpaired peak concentrati on, essentially matching the August 5, 1997 observed concentration of 188 ppb. CA LGRID and CAMx performed better in recreating the timing and location of the observe d peak ozone concentr ation. Use of the SAPRC99 chemistry in CALGRID and CA Mx increased model performance in simulating the unpaired peak concentration compared with the CB-IV chemistry. However, both models conti nued to under predict, faili ng to predict the peak concentration within ten percent of the observed concentration.Final 2003 AQMP Appendix V: Modeli ng and Attainment Demonstrations

V- 1 - 6 Preliminary Future Year Simulations

Three of the five model-chemis try combinations were run to simulate attainment of the ozone standard in 2010 with the oxides of n itrogen (NOx) emissions held at the final 1997 AQMP level. The preliminar y results varied significantly in the determination of the volatile organic compound (VOC) carrying capacities required to meet attainment criteria. (CAMx/CB-IV and CALDRID/ CB-IV under predicted unpaired peak concentrations greatest in the base year simulation and in-tur n were excluded from future consideration). The 2010 emissions were considered preliminary since they represent across the board reductions from the final base-year totals and did not reflect implementation of a specific control strate gy. CAMx/SAPRC99 which had the lowest unpaired predicted to observed peak ratio pr ojected the highest (VOC) carrying capacity of 560 TPD. CALGRID/SAP RC99 which had the second be st unpaired predicted to observed peak ratio predicted a VOC ca rrying capacity of 420 TPD, essentially equivalent to the VOC esta blished by the 1997 AQMP. The 330 TPD carrying capacity derived by UAM was roughly equi valent to that defined by the 1991 and 1994 AQMP’s.
With the large spread in proj ected carrying capacity not reso lved, an independent test of model performance was run to try and refine th e model selection process. Emissions for 2002 were generated and simu lated by the three modeling systems. The process was essentially a “mid course” analysis that is recommended in EPA’s modeling guidance as part of a weight of evidence analysis to support model validation and acceptance. Average ozone air quality from four days during the summer of 2002 having similar meteorological profiles to the primary episode day (August 5, 1997) was used to validate predictions. The days in 2002 were ranked within a range of ± 6 out of 2557 cases based on a statistical analysis (descr ibed in Chapter 3). The f our-day average concentration was 150 ppb but included the observed annual Basin maximum one hour average concentration of 169 ppb. The results of th e “mid-course” simulations are presented in Table 1-2 for both the Draft and 2003 AQMP emissions inventor ies. Revisions to the 2002 emissions inventory following the releas e of the Draft 2003 AQMP resulted in an increase of 24 TPD of VOC in the Basin and a reduction of 6 TPD of NOx. The analysis shows that the UAM performed best on th is independent test for the Draft 2003 inventory. When VOC emissi ons were increased for the fi nal inventory, UAM slightly over predicted the four day average but recr eated the peak concentration observed in 2002. Even with the additional VOC em issions, CALGRID was not able to produce additional ozone. Note, CAMx was not run using the 2003 AQMP emissions for the “mid-course” analysis.

Table 1-2
2002 "Mid-Course" Ozone SimulationChapter 1 Modeling Overview

V - 1- 7 Predicted Maximum 1-Hour Average Ozone Concentration (ppb) for the August 5, 1997 Observed Meteorology Predicted Maximum 1-Hour Average Ozone as a Percentage of 2002 150 ppb Four-Day Average Observed Maximum Concentration Model/Chemistry

Draft 2003 AQMP Emissions 2003 AQMP Emissions Draft 2003 AQMP Emissions 2003 AQMP Emissions

UAM/CB-4 158 170 105 113

CALGRID/SAPRC99 141 141 94 94

CAMx/SAPRC99 134 N/A 89 N/A

Independent Review
To help resolve the model selection process a panel of expert ai r quality modelers was convened to review the application of a nd resulting model simula tions for the five modeling systems. Table 1-3 lists the member s of the panel. The panel members were provided with background mate rial, baseline performance evaluations and preliminary future year simulations. The panel members met with District and ARB modeling staff to discuss the varying aspect s of the modeling analyses and prepare a critique of the work conducted. The peer review was conduc ted to ensure that model selection was governed by the technical merit and perform ance of each model, and not biased by model results. The text of the modeling criti ques is presented as an attachment to this document. The recommendations of the pane l are summarized in th e following bullets. The panel

o endorsed the use of state-of-the-science air quality modeling platforms such as CALGRID and CAMx

o endorsed the use of state-of-the-scien ce chemical mechanisms such as SAPRC99

o recognized that the ability of models to accurately predict peak observed concentrations was critical for model app lication to simulate future air quality

o recognized staff's familiarity and appli cation experience as a key factor in selecting a modelFinal 2003 AQMP Appendix V: Modeli ng and Attainment Demonstrations

V- 1 - 8 o recommended that the meteorological mode l’s recreation of the episodes used by the models be re-evaluated

o recommended sensitivity simulations to te st “relative reduction of emissions” for those models that under-predicted base analyses

Table 1-3 Independent Review Expert Pa nel Members and Affiliations

Panel Member Affiliation
Dr. C. Shepard Burton Independent C onsultant (Formerly with Systems Applications, Inc.)

Dr. Judith Chow Desert Research Institute
Dr. Robert Harley University of California at Berkeley
Mr. Fredrick Lurmann Sonoma Technology, Incorporated
Dr. Ned Meyer Independent Consulta nt (Formerly with U.S. EPA – OAQPS)

Dr. John Seinfeld Californi a Institute of Technology
Mr. Mel Zeldin Independent Consu ltant (Formerly with the SCAQMD)

In general, the model that fared best fro m the critique was CALGRID/SAPRC99. It was recommended that the CAMx/SAPRC99 modeling be further reviewed considering that CAMx has been successfully applied for oz one attainment demons trations nationwide and has been used in ozone analyses in other countries without the problems encountered in the current AQMP modeling demonstration. However, the panel did not rule out the use of UAM as a modeling tool de spite its older formulation and chemistry. In fact, experience gained in implementi ng UAM and interpreting the impacts of the simulation results in prior AQMP’s provides a large measure of conf idence in the model performance. This is demons trated both in the model’s ab ility to simulate peak ozone concentrations for the August 4-7, 1997 meteor ological episode and in the capacity of the model to estimate observed Basin ma ximum ozone concentrations for 2002.
Responding to the panel’s recommendations, se veral simulations were conducted using CAMx/SAPRC99 and CALGRID/SAPRC99 to test the relative level of VOC emissions reductions that would be required to meet a “64 ppb” future year oz one reduction. (TheChapter 1 Modeling Overview

V - 1- 9 64 ppb level represents the difference be tween the August 5, 1997 observed maximum 1-hour average concentration and the federa l standard of 124 ppb). When the relative reduction techniques were applied to the CALGRID/SAPRC99 and CAMx/SAPRC99 model runs, the projected VOC carrying capacities closed the gap with the UAM carrying capacity. Yet the CAMx runs pr oduced the highest VOC carrying capacities and given the base year and “mid course ” correction simulations being significantly under predicted, continued use of th e model for the 2003 AQMP attainment demonstration was ruled out.

Modifications were made to several meteor ological fields to a ttempt to increase the CALGRID/SAPRC99 base-year peak ozone prediction. These actions included adjustments to the vertical mixing prof iles and smoothing of meteorological field parameters. These adjustments and simu lating with the final 2003 AQMP emissions resulted in a nominal increase in base-year performance wher e the peak predicted ratio increased to 0.89 (a maximum predicte d concentration of 167 ppb). Additional modifications were made to the methodology used to roll back future-year boundary conditions. CALGRID/SAPRC99 was extensiv ely simulated using the final emissions control strategy. The initial results of th e simulations indicated that the SAPRC99 mechanism was very “stiff” a nd not responsive to reductions of VOC at targeted levels of NOx (approximately 541 TPD). One area of concern was the impact of biogenic emissions, both in emissions tonnage on the primary modeling day and in the complexities in the speciation of the bi ogenic volatile organi c compounds for the SAPRC99 chemical mechanism. With the uncertainties of th e response of the chemical mechanism to the proposed control st rategy, it was determined that the CALGRID/SAPRC99 mechanism needed further evaluation.
Sensitivity analyses, including the use of th e ozone apportionment tool, were conducted for both CALGRID/SAPRC99 and UAM to test the contribution of biogenic emissions to the 2010 predicted ozone. The sensitivity analyses indicated that the biogenic emissions were contributing about 30 percent to the peak predicted concentration, regardless of modeling platform. While relativ e weight of the biogenic emissions to the total ozone formation was considered “high” the results for the two models were similar, despite the differences in the chemical mech anisms and the SAPRC99 speciation profile.
The CALGRID/SAPRAC99 2010 predicted pe ak ozone concentration for the 2003 AQMP emissions and the primary control sc enario (modeling remaining emissions of 314 TPD of VOC and 519 TPD of NOx), valued 117 ppb. As with the preliminary simulations, the sensitivity to reductions in VOC at the set level of NOx emissions was low, translating to an a pproximate 16 TPD of VOC re duction for each ppb of ozone reduced. (This approximate ratio was demons trated for several NOx thresholds through modeling conducted by the ARB using across th e board emissions reductions). Scaling the federal standard by the ratio that CALGRID/SAPRAC99 under predicted the baseyear ozone peak provides an alternate equi valent standard of 110 ppb. This is aFinal 2003 AQMP Appendix V: Modeli ng and Attainment Demonstrations

V- 1 - 10 modified version of the panel’s recommenda tion to test the relative level of VOC reduction needed to account for under predicti on in the base-year simulation. If this scaled standard were the target for em issions reductions, significant additional reductions of VOC emissions would be necessary.
UAM was selected as the pr imary modeling tool to determine the Basin emissions carrying capacities for the 2003 AQMP. The pr imary reasons for selecting UAM are:

o UAM predicted the unpaired peak conc entration best in the validation

o UAM performed the best in the “mid-course” correction simulation

o Staff has extensive experience with the model application
The AQMP process is committed to continue to evaluate CALGRID and CAMx (using CB-IV and SAPRC99 chemistry). As with CALGRID, the modeling staff is continuing to evaluate the CAMx perform ance to bring it in line with the other two models. The UAM will remain as the primary modeling t ool for the 2003 AQMP. A technical report discussing the CALGRID simulations analys is is provided as Attachment–7 to AQMP Appendix V.

Meteorological Episode Selection

The UAM ozone attainment demonstration was based on two mete orological episodes: August 5-6, 1997 and August 27-28, 1987. Model input data supporting the UAM simulations were derived from intensive fi eld monitoring that occurred during the 1997 Southern California Ozone Study (SCOS97) and the 1987 South California Air Quality Study SCAQS. The SCOS97 study benefited fro m state-of-the art upper air wind and temperature monitoring and recently develope d advances in partic ulate and oxides of nitrogen sampling technology. The SCAQS fiel d program was the state-of-science in 1987, however the extent and s ophistication of field monito ring was now ten years older than that used in SCOS97. US EPA require s that meteorological episodes and the data supporting the modeling attainment demonstration be no more th an ten years old for this very reason. The August 5-6, 1997 episode was selected as the primary modeling episode. The August episode was the Basin second ma ximum ozone for 1997, and the 188 ppb is equivalent to the current ozone design value (185 ppb). As part of the episode selection process, all days during the months May through October c overing the period 1981 through 2002 were ranked by ozone meteorological episode potential. The statistical empirical analysis (described further in Chap ter 3) is equivalent to that itemized by Cox and Chu and the 1996 revisions to EPA Ozone Modeling Guidance. Using the rankingChapter 1 Modeling Overview

V - 1- 11 system, the August 1997 episode was identified as being more severe than the August 1987 episode. The 1987 SCAQS episode however, was retained for the analysis as a measure of consistency between mode ling attainment demonstrations.
Overall, the days represented by the two meteorological episodes fall into the “highozone” category. While it is desirable to ha ve a distribution of different meteorological episodes to study, over the past five years, the days exceeding the ozone standard have become more and more restricted to the high ozone potential day.
Two additional SCOS97 meteorological ep isodes were considered for potential simulation: (1) September 28-29, 1997, a weekend episode and (2) October 31- November 1, 1997. Model performance for the September episode did not meet EPA criteria and it was excluded from this analysis . The October-November episode is being used for the current 2003 CO attainment de monstration. One additional episode was considered, July 14-18, 1998, however, th at episode represented meteorological conditions that are severe and rare, occurring less than once in a four year period. The statistical ranking of the episode days conf irmed the severity of the July 14-18, 1998 meteorological episode (i.e. 99.8 th percentile of the past 22-ye ars). As a consequence, that episode was excluded from the attainment demonstration.
The meteorological and air qua lity field data monitored during the August 1997 episode has been extensively analy zed over a two year period by the SCOS97 Meteorological Working Group as well as NOAA a nd contracted air quality consultants. The data has undergone extensive quality assurance and the ensuing meteorological model input developed from the data has been evaluated using the state-of-science meteorological models.

Carbon Monoxide
CAMx, with CB-IV chemistry and the CA L3QHC roadway intersection "Hot Spot" model were the modeling tools used in the 2003 AQMP carbon monoxide modeling attainment demonstration. In the 1997 CO Plan, the regional dispersion modeling was conducted using UAM as a modeling platform. CAMx, with its fixed layer height vertical structure was selected for the current application because it is more suited to address ground level carbon monoxide impacts from tailpipe emissions and low level wind drift of regional carbon monoxide background concentra tions. CAMx was run with the CB-IV chemistry; however, carbon monoxide is essentially inert in the fall nighttime application. As a consequence, the modeling effort was focused towards regional transport and local dispersion.
A new modeling episode was introduced for the modeling attainment demonstration, October 31, - November 1, 1997. The me teorological episode was the final SCOS97 intensive monitoring of the active program and benefited from the extensive fieldFinal 2003 AQMP Appendix V: Modeli ng and Attainment Demonstrations

V- 1 - 12 monitoring in place. Three specific aspects of the episode are important to note: First, the episode took place on a weekend beginni ng on Friday night and carrying through Saturday morning. Second, the episode be gan on Halloween night and it is difficult to estimate the local traffic impact resulting fro m the holiday activities. Finally, while not as severe an episode as was used in the previous AQMP's, the October 31, - November 1, 1997 episode was the second most severe since Phase II fuel reformulation was implemented and has not been surpassed in concentration since its occurrence.
The 2003 CO Plan will serve as a replacement for the 1997 CO Plan that lapsed in 2000. Over the two year period since the attainme nt demonstration lapsed the Basin has met the criteria for attainment of the federal 8- hour average carbon monoxi de standard. (The Basin did not exceed the federal 8-hour av erage carbon monoxide st andard in 2001 and exceeded the standard only on ce in 2002). Thus, the 2003 CO attainment demonstration will provide the basis for a future maintena nce plan for the Basi n pending submission of a petition for redesignation of attainment status.



### DOCUMENT ORGANIZATION
This document provides the federal attainment demonstrations for PM 10 , ozone and carbon monoxide. Chapter 2 provides the PM10 attainment demonstration to meet the 2006 attainment date. The disc ussion includes future year (2010) particulate impacts for both PM10 and PM2.5. Chapter 3 presents th e ozone attainment de monstration based on the UAM modeling analyses. The ozone anal ysis includes a characterization of the episode, base-year modeling performance, and future year attainment for two control strategies. As with the particulate analysis, a series of alternative emissions simulations are presented to test the sens itivity of the proposed control st rategy. Chapter 4 presents the CO attainment demonstra tion and it includes a detailed an alysis of the emissions, and observed meteorological episode. The list of references cited in the document follows.
Table 1-4 lists the Appendices and Attachments to this document.Chapter 1 Modeling Overview

V - 1- 13 Table 1-4 Appendices and Attachments
Appendix/Attachment Description
Appendix A Model Performance Sta tistics and Graphical Evaluation
Attachment-1 ARB/District Modeling Protocol
Attachment-2 The Critiques of the expert Researcher's panel
Attachment-3 Mid-term Critiques of the Independent Reviewers
Attachment-4 CEPA Source Level Emissions Reduction Summary for 2006: Annual Average Inventory
Attachment-5 CEPA Source Level Emissions Reduction Summary for 2010: Annual Average Inventory
Attachment-6 CEPA Source Level Emissions Reduction Summary for 2010: Planning Inventory
Attachment 7 Technical Repor t: CALGRID Ozone Simulations

## CHAPTER 2 REVISION TO THE FEDERAL PM10 ATTAINMENT DEMONSTRATION PLAN AND VISIBILITY ASSESSMENT

Introduction
Ambient Data Characterization and PTEP Modeling Approach Emissions Inventory
Base-Year Simulations Future Air Quality Conclusions (Particulates) Visibility Conclusions (Visibility)Chapter 2 PM 10 Attainment and Visibility

V - 2- 1 

### INTRODUCTION
In the 1997 AQMP the Urban Airshed M odel with Linear Chemistry (UAM/LC) [Kumar, et al, 1995] modeling system t ogether with the Chemical Mass Balance (CMB) receptor model provided the platforms for simulating the base and future year PM10 concentrations for the Basin. EPA guidance on PM modeling requires the use of a dispersion model in combination w ith a receptor model for attainment demonstrations. The UAM/LC modeling system is a multi layered, Eularian grid model with a parameterized linear chemistr y used to simulate secondary aerosol formation in the atmosphere. UAM/LC wa s used to simulate annual primary and selected secondary aerosol components (ammonium, sulfates and nitrates) for the model year 1995. The CMB receptor model used a Sout h Coast Air Basin specific emissions source profile to estimate se condary organic components. The model simulations were supported by corroborating analyses including a modified speciated rollback calculation, and the use of an episodic PM10 model, UAM-AERO in conjunction with a statistical analysis to extrapolate the episodic simulation for an annual application. A detailed descripti on of the modeling approach, tools used and data used in the analyses is presented in Chapter 2 of Appendix V to the 1997 AQMP.
The 1997 AQMP focused on simulating annual particulate for five key sites in the Basin (Rubidoux, Fontana, Diamond Bar, Anaheim and Central Los Angeles) where enhanced field measuremen ts were conducted during 1995 through the PM10 Technical Enhancement Program (PTEP). The PTEP data provided comprehensive analysis of the component spec ies of both the fine and coar se partitions of particulate samples. The PTEP field program captured particulate data on 222 days in 1995, with a focus towards the fall and early winter months when high values of secondary components, in particul ar nitrate are often observed. The particulate profile has been roughly grouped into six general components including the ions ammonium, nitrate, and sulfate; organic carbon, elemental ca rbon and primary matter (others). The PTEP program is described in detail in Ch apter 2 of Appendix V of the 1997 AQMP.
Subsequent to the submission of th e 1997 AQMP PM10 pl an, efforts were undertaken to enhance the annual PM si mulation capability and extend the analyses to PM2.5. Desired components of th e UAM/LC and UAM-AERO models were merged and enhanced by incorporating a parameterized aerosol chemistry module into the UAM-Flexible Chemistry Model (UAM-FCM) [Kumar, et al, 1995] with PM2.5 partitioning. The resulting UAMAERO -LT (LT-long term) model provided a more robust, stand-alone platform for pr imary and secondary particulate simulation including secondary organic species. The UAMAERO-LT is described in more detail in a following section.Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 2 For the 2003 AQMP, PM10 and PM2.5 modeling was cond ucted using the UAMAERO-LT model for the 1995 base year. Simulations were conducted for the same modeling gridded domain as the 199 7 AQMP using a modified version of the 1995 base year meteorological input data and 5-layers (compared with two used for the UAM/LC simulation). The emissions inventories have been significantly upgraded to address enhancements to the on-road and off-ro ad mobile source inventories through EMFAC2002. Additional updates in the point and area source inventories and the ammonia inventory have been added to the simulation.
The 1997 AQMP merged the results of receptor an d dispersion modeling techniques to simulate annual and 24-hour averaged maximum concentrations of PM10 to demonstrate future year attainment. The 2003 AQMP relies on a deterministic approach using the UAMAERO-LT to simulate base and future year annual average PM10 and PM2.5. While the emissions inventory is specified for weekdays, Saturdays and Sund ays, and is temperature corrected for each month, short-term episodic modeling using this inventory is inappropriate to estimate maximum 24- hour PM10 and PM2.5 concentrations fo r the Basin. Linear rollback on the particulate component species is used to estimate futu re maximum 24-hour average particulate concentrations. In addition, a weight of evidence discussion is provided to address uncertainties in the analysis and provide support that the regional modeling is demonstrating future year a ttainment of the particulate standard.
The following sections briefly describe the 1995 air quality profile and PTEP, address the characterization of the UAMAERO-LT modeling platform, modeling domain, meteorological fi elds, boundary and initial conditions, and emissions uncertainties. The results of the base year simulation are compared to observations to quantify model performance. The future base year and controlled emissions simulations are presented to demonstrat e attainment of the annual and 24-hour maximum PM10 standards in 2006. Additi onal future year (2010) simulations are presented to demonstrate progress made to wards attaining the new PM2.5 standard (date yet to be determined ) and the additional emissions reductions that will be needed to achieve that goal. Finally, the analysis addr esses the post 2010 emissions reductions that will be needed to attain the recently re vised California PM10 and PM2.5 standards.



### AMBIENT DATA CHARACTERIZATION AND PTEP
The 1995 ambient particulate air quality setting in the Basin and the PTEP monitoring program ar e extensively characterized in Appendix V of the 1997 AQMP. This section provides a brief summary of the PTEP data analysis and an expanded assessment of the SSI Hi-Vol data measured at the District monitoring sites. Figure 2-1 shows the locations of both the PTEP s ites and the District’s network of SSI HiVol monitoring locations.Chapter 2 PM 10 Attainment and Visibility

V - 2- 3 FIGURE 2-1 Particulate Monitoring Network: SSI Hi -Vol and PTEP Enhanced Monitoring Network in Bold (San Ni cholas Island not shown)
Annual Average Concentrations
Figures 2-2 and 2-3 depict the relative c ontributions of the major components of particulate to the annual average PM10 a nd PM2.5 measured at each of the PTEP sites. In the figures, the sites are presente d in a west to east orientation whereby the offshore background site SANI (San Nicholas Island) is on the left of the figure and Rubidoux farthest right. This orientation is aligned with wind driven mass transport in the Basin. In general, the west Basin stations of ANAH (Anaheim), CELA (Central Los Angeles) and DBAR (Diamond Bar) are relatively consistent in percentage component mass with CELA e xhibiting higher nomina lly nitrate, and organic carbon fractions. In contrast, concen trations of nitrate, organic carbon and others (including wind blown dust, and primary geological material) are dominant at the eastern Basin sites of FONT (Fontana) and RIVR (Rubidoux) that are subjected to transport and enhanced secondary aero sol formation due to ammonia emissions from upwind dairy and farming operations in those areas.Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 4 The PM2.5 component analysis shows a simila r pattern to that of PM10 however the percentage contributions are adjusted to reflect the near absence of the primary category (others) in the fine particulate porti on of the distribution. In general, PM2.5 total mass is more associated with combus tion related sources and secondary aerosol formation.
It is important to note that PTEP sampling took place on 222 days during 1995. The District’s ambient SSI sampling program operated on approximately 61 days that year. PTEP sampling was conducted at a ll six sites on a one-day-in-six schedule during the first quarter of 1995. The sampling frequency was increased to one-dayin-three during the second quarter of 1995 , and during the second half of 1995, sampling frequency was increased to every da y. Only San Nicolas Island (due to logistical limitations) remained on a one- day-in-six sampling schedule. Table 2-1 provides a comparison of th e annual average concentrations measured at the PTEP sites and the co-located SSI data sampled for a routine one-day-in-six schedule. When all data is analyzed, with the exception of Anahei m, the PTEP annual average concentration was higher than the correspond ing SSI annual averag e. When the data is paired by SSI sampling day, the annual averages agree well at all sites.

FIGURE 2-2 1995 PTEP Annual Average Speciated PM 10 Concentrations 0 10 20 30 40 50 60 70 80

SANI ANAH CELA DBAR FONT RUBX

SO4 NO3 NH4 OC EC Na Cl Others μg/m 3Chapter 2 PM 10 Attainment and Visibility

V - 2- 5 FIGURE 2-3 1995 PTEP Annual Average Speciated PM 2.5 Concentrations

Table 2-1
Comparison of the PTEP and SSI 1995 Annual Average PM10 Concentrations

PTEP SSI Paired PTEP/SSI Location Annual Average (μg/m 3 ) Number of Samples Annual Average (μg/m 3 ) Number of Samples Annual Average (μg/m 3 ) Number of Samples

Anaheim 42.2 141 43.5 60 42.3 53

Central Los Angeles 52.0 141 42.8 60 50.1 55

Diamond Bar 46.5 140 46.0 61 46.8 51

Fontana 66.8 137 61.0 61 64.1 52

Rubidoux 78.0 157 69.0 61 74.0 56

The federal PM10 annual standard is base d on the SSI sampler data measured on the one-day-in-six schedule. While the samplin g frequency of PTEP was greater than the SSI, there were periods ear ly in 1995 when only the SSI analysis was available. As a result, the PTEP data was not dire ctly used for annual model validation. 0 5 10 15 20 25 30 35 40 45

SANI ANAH CELA DBAR FONT RUBX

SO4 NO3 NH4 OC EC Na Cl Others μg/m 3Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 6 Instead, the PTEP data was used to apportion the SSI measured annual arithmetic mean total mass (e.g. 69 μg/m 3 at RIVR) into the majo r particulate component species. Table 2-2 (repeated from 1997 AQMP Appendix V) lists percentage contributions of the individual species for each PTEP site ba sed on the annual sampling program. For the UAMAERO-LT modeling validatio n and attainment demonstration, the percentage mass contribu tions of the major particulate species to the total mass analyzed fro m the site specific PTEP data are multiplied by the corresponding SSI annual average mass concentrations at the five SSI sites to estimate annual averages of the particulate component species. Table 2-3 summarizes the component mass of the apportioned SSI PM10 data.
Figure 2-4 shows the Basin-wide dist ribution of annual arithmetic mean PM10 concentrations for 1995. The highest concen trations are located in the eastern Basin at Rubidoux and Fontana with annual averag e concentrations abov e 50.4 backing into parts of Orange and Los Angeles Coun ties. The gradation of particulate concentrations that is evident in the figure is substantiated by annual average concentrations measured at the District’s SSI monitors presented in Table 2-4. The SSI data and the analyzed spatial dist ribution provide an enhanced basis for estimating the base-year UAMAERO -LT simulation performance.

TABLE 2-2 Annual Average PM 10 Species Concentrations at the Five Basin PTEP Sites

Anaheim Downtown LA Diamond Bar Fontana Rubidoux Component

Mass % Mass % Mass % Mass % Mass %

PM 10 mass 42.16 51.97 46.52 66.84 77.98

Sulfate 4.71 11.2 5.16 9.9 4.38 9.4 3.95 5.9 4.51 5.8

Nitrate 10.14 24.1 11.90 22.9 11.98 25.7 14.67 22.0 19.84 25.4

Ammonium 3.92 9.3 4.80 9.2 4.67 10.0 5.10 7.6 6.74 8.6

Organic carbon 7.16 17 10.18 19.6 8.70 18.7 11.41 17.1 11.90 15.3

Elemental carbon 2.78 6.6 4.30 8.3 3.57 7.7 4.02 6.0 3.56 4.6

Sodium 1.37 3.3 1.31 2.5 1.04 2.2 0.88 1.3 0.93 1.2

Chloride 0.64 1.5 0.62 1.2 0.41 0.9 0.49 0.7 0.56 0.7

Others* 11.42 27.0 13.69 26.3 11.77 25.4 26.32 39.4 29.93 38.5 *Primarily Crustal ComponentsChapter 2 PM 10 Attainment and Visibility

V - 2- 7 TABLE 2-3 Apportioned SSI Annual Average PM 10 Species Concentrations (μg/m 3 )

Component Anaheim Central LA Diamond Bar Fontana Rubidoux

Ammonium 4.0 3.9 4.6 4.6 5.9

Nitrate 10.5 9.8 11.8 13.4 17.5

Sulfate 4.9 4.2 4.3 3.6 4.0

Organic Carbon 7.4 8.5 8.6 10.4 10.5

Elemental Carbon 2.9 3.7 3.5 3.7 3.2

Others* 13.8 12.8 13.1 25.3 27.9

Total PM10 Mass 43.5 42.8 46.0 61.0 69.0 *Includes: Primarily Crustal Components, Sodium and Chloride Maximum 24-Hour Average Concentrations
Figure 2-5 depicts the specie s breakdown of particulate fo r four of the peak 24-hour average PM10 and PM2.5 concentrations me asured at Rubidoux during PTEP. What stands out most prominently is the variation in the others (primary particulate matter) and nitrate categories from da y-to-day. April 9, 1995 is a “hig h wind” day that measured 219 ug/m3 from the SSI. PM2.5 c oncentrations on that day were less than 40 ug/m3. In contrast, December 11, 1995 is a day where meteorological conditions enhanced secondary aerosol formation and nitrate has the greatest contribution to total mass. PM2.5 concentrations on December 11, 1995 exceeded 100 μg/m 3 with little or no contribution from primary particulate. The fi ne and coarse particulate samples for that day display relatively e quivalent concentra tions of nitrates, ammonium, and elemental carbon.Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 8 FIGURE 2-4 1995 Annual Average PM10 in the South Coast Air Basin

FIGURE 2-5 Four Highest 24-Hour Average PM 10 and PM 2.5 Days at Rubidoux Los Angeles

Riverside

NOT EXCEEDED 50 - 60 60 - 70 70 - 80 OVER 80 μg/m 3 Anaheim San Bernardino

SCAQMD AIR MONITORING NETWORK

M ILES 0 25 SOUTH COAST AIR BASIN (SCAB) COUNTY LINES
AIR MON ITORING STATION

JUNE 1996 VERSION Long Beach 20

Federal Standard 30

30 20

40 50 60

0 50 100 150 200 250

PM10 PM2.5 PM10 PM2.5 PM10 PM2.5 PM10 PM2.5

SO4 NO3 NH4 OC EC Na Cl Others 11/17/95 10/13/95 12/11/95 04/09/95 2 μg/m 3Chapter 2 PM 10 Attainment and Visibility

V - 2- 9

Table 2-4
1995 Southern California SSI Annual Average PM 10 Concentrations

Location County/Air Basin Annual Average Concentration (μg/m 3 )

Central LA Los Angeles/SCAB 42.8

Hawthorne Los Angeles/SCAB 36.2

N. Long Beach Los Angeles/SCAB 38.7

Burbank Los Angeles/SCAB 42.2

Azusa Los Angeles/SCAB 49.1

Pomona/Diamond Bar Los Angeles/SCAB 46.0

Santa Clarita Los Angeles/SCAB 37.0

Anaheim Orange/SCAB 43.5

El Toro Orange/SCAB 37.6

Norco Riverside/SCAB 54.2

Rubidoux Riverside/SCAB 69.0

Perris Riverside/SCAB 46.7

Banning Riverside/SCAB 30.1

Ontario San Bernardino/SCAB 54.0

Fontana San Bernardino/SCAB 61.0

San Bernardino San Bernardino/SCAB 57.3

Redlands San Bernardino/SCAB 48.4

Crestline San Bernardino/SCAB 20.4



### MODELING APPROACH
As previously stated, th e 2003 AQMP PM10 attainme nt demonstra tion modeling relies on a deterministic approach using the UAMAERO-LT to simulate base and future year annual average PM10 and PM2.5. Gridded pa rticulate predictions for the 1995 base and 2006 controlled emissions ar e provided as part of a comprehensive assessment of model performance. Linear rollback of the 1995 PTEP observed 24-Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 10 hour maximum average PM10 and PM2.5 concen trations at the five key sites is used to estimate future (2006 and 2010) maximum 24-hour average particulate concentrations.
EPA’s PM10 guidance requires attainment demonstrations to incorporate monitored data that presents a compre hensive component analysis of the particulate mass. The 1995 PTEP field program provides the comprehensive-speciated data characterization of the PM10 and PM2. 5 mass required for the analysis and validation of the particulate modeling. Th e PTEP data from six-sites (five in-Basin and one upwind island background) prov ides a geographically representative distribution of speciated particulate in th e coastal, metropolitan, near valley and inland receptor areas.
In 1995, the District’s particulate monito ring network operated Size Selective Inlet (SSI) Hi-Vol samplers at 18 additional lo cations in the Basin. The routinely monitored PM10 data (sampled on a 6 th day observation frequency) provided direct characterization of the mass of nitrate, su lfate and chloride. Components such as ammonium, organic carbon, elemental carbon and other primary species are grouped together and are estimated by subtracti ng the difference in the total mass from the three specific components. Wh ile the SSI procedure provid es a reliable estimation of the mass volume, the filter method suffers from uncertainties in the estimations of nitrate and total mass due to evaporation of ammonium nitrate that takes place on the filter media.
The SSI data was not directly used in the 1997 AQMP modeling analyses for the purpose of model validation in the UAM/LC annual PM10 attainment demonstration. In the current analysis, th e SSI data (total mass) is used to corroborate the UAMAERO-LT model performance as part of a weight of evidence demonstration. Model performance at the expanded number of monitoring sites is used to refine the spatial representativeness of the simulations. In add ition, model performance across the Basin at the SSI sites s hows both over and under pred iction of the annual PM10 average concentration. This provides a measure of confidence that while the surrogates used to distribute the emissions may have uncertainties, the countywide emissions totals are reasonable.
An additional weight of evidence discussi on is provided to address uncertainties in the emissions inventory, mainly in the primar y PM10 dust categories. As part of that discussion, an analysis of the "hot-spot" gr ids is provided to support the future year regional modeling attainment demonstration.

The 1997 emissions i nventory described in Appendix III of the 2003 AQMP was projected to 1995 for the UAMAERO-LT modeling applications.Chapter 2 PM 10 Attainment and Visibility

V - 2- 11 Six scenarios were evaluated for base and future year PM 10 and PM2.5 air quality: (1) 1995 baseline, (2) 2006 base line without controls, (3) 20 06 with control measures implemented, (4) 2010 base line without controls, (5) 2 010 with control measures implemented (Option-1), (6) 2010 with co ntrol measures implemented excluding federal sources (Option-2). Projections of future PM 10 air quality were estimated based on emissions projections by source category for each scenario.

UAMAERO-LT
As previously stated, the 1997 AQMP used a combination of different modeling techniques (receptor and p hotochemical grid models) to estimate the source contributions to ambient PM10 levels as measured at different monitoring sites. The primary modeling tools were CMB (r eceptor) and UAM/LC (dispersion and secondary aerosol simulation). These models are viewed as viable tools for control strategy development. Each model howeve r has desired and limiting aspects to its use. For example, CMB is easily implem ented and will provide characterization of secondary organic compounds when a cont emporary detailed set of emissions source profiles is available. If the source profile is out-of-date, inaccuraci es can arise in the analysis. UAM/LC provides a platform to simulate secondary concentrations of nitrate, sulfate, and ammonium as well as primary particulate. The empirically derived gaseous and aerosol chemistry is designed for speed of application and as such does not incorporate a full gas-phase ch emical module. As a consequence, the model is heavily depe ndent on ambient air quality data and is unable to simulate all of the major aerosol components.

The 1997 AQMP also featured of the intr oduction of the episodic UAMAERO model as a tool to analyze short-term (24-hou r averaged) PM10 impa cts. The UAMAERO platform operates both gas phase chemistry (Carbon Bond -IV with extensions) and a size resolved aerosol modu le. The structure of th e episodic UAMAERO model jointly satisfied the EPA requirements for secondary aerosol simulation and the dispersion of primary particulate comp ounds. The PM10 simulation model was evaluated for a fall episode using day specif ic air quality and meteorology. Model performance was promising. However, data requirements and computational constraints caused by the complex aerosol chemistry placed restraints on extending the model application beyond a few select ed days. An annual application of UAMAERO was impracticable.

In 2000, the District fu nded the development of the UAMAERO-LT. UAMAEROLT is a computationally efficient, simplif ied version of the UAMAERO model that includes several desired features not available in the UAM/LC. The newly developed UAMAERO-LT model is a simplified version of the UAMAERO model. The detailed thermodynamic routine (ISOROPIA) of the UAMAERO model [Pandis,Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 12 et al, 1992] was replaced w ith the empirical parameteri zed inorganic gas/aerosol partitioning module used in the UAM/LC. The secondary organic aerosol formation scheme was replaced with a condensed vers ion of the Carnegie Melon University secondary organic aerosol module (Strader et. Al., 1999). The CMU module treats organic products as semi-volatile species a nd employs an equilibrium approach to the gas/aerosol partitioning of these species. In addition, the detailed particle-sizing scheme used in the UAMAERO model was also replaced by an observation-based, two size (fine and coarse) particle-siz ing scheme for secondary aerosols. UAMAERO-LT utilizes a full Ca rbon Bond IV gas-phase chemical mechanism and simulates the formation of particulate nitr ate, sulfate, ammonium, organic carbon, elemental carbon and other primary particle s. Table 2-5 highlights selected key differences between the UAM/LC and UAMAERO-LT modeling systems.

Table 2-5
Comparison of UAM/LC and UAMAERO-LT

Element UAM/LC UAMAERO-LT
Dispersion Platform UAM-IV UAM-IV

Particulate Resolution Coarse Coarse and Fine
Gas Phased Chemistry Empirical Linear Chemistry Carbon Bond-IV (FCM)

Aerosol Chemistry Empirical Linear Chemistry Empirical Linear Chemistry
Secondary Organic Aerosol Chemistry None Modified Condensed CMU Aerosol



### UAMAERO-LT Model Inputs
The procedures for UAMAERO-LT input file preparation are presented in this section. Much of the following di scussion is based on the ozone/PM 10 modeling protocol developed for the 1997 AQMP re vision (Draft Working Papers #M-1 and M-2, 1996). Parts of this document ar e based on the EPA and ARB technical guidance on ozone modeling (ARB, 1992) and (EPA, 1991 and 1996). While the UAMAERO-LT chemical mechanism is signi ficantly different from previous UAM versions, the majority of the input files have the same form at and/or information.Chapter 2 PM 10 Attainment and Visibility

V - 2- 13 A series of procedures and methodologies were defined for the preparation of the UAM meteorological and air quality input files. The model input preparation procedures are discussed in Technical Report V-B of the 1994 AQMP. For the UAMAERO-LT annual simulations selected mo difications were made to the input fields. Deviations from the procedures used in the 1994 AQM P are noted in the following subsections.
Modeling Domain
The UAMAERO-LT modeling region used to simulate PM10 and PM2.5 for the 2003 AQMP extends 325 km in the east-west direction and 200 km in the north-south direction, beginning at the UTM location of 275 easting and 3670 northing. The horizontal extent of the domain used for the UAMAERO-LT analysis is larger than that used for the UAM/LC simulations in the 1997 AQMP. Horizontal grid cell resolution was 5 km, as was used in prev ious UAM modeling applications for the Basin.
The vertical dimensions of the modeling dom ain are based on previ ous experience in UAM applications for the Basin and elsewher e. The height of the modeling domain for the UAMAERO-LT simulations was set to a constant 2000 m above ground level. Five spatially and temporally varying layers (based on the mixing height) are used.
Boundary, Top and Initial Air Quality Concentrations
One major change to the mode l input is the use of time varying boundary conditions. A modified version of the EPA continen tal average boundary conditions "EPAClean" for gaseous pollutants was used as a starting point for the boundary and model-top concentration assi gnment. Hydrocarbon specia tion profiles developed for the 1994 AQMP [Technical Repo rt V-B (1994)] were used to specify the required species. Based on preliminary simu lations for 1995, ambient NO and NO2 concentrations were reduced 50 percent to 0.5 and 1.0 ppb resp ectively. The initial condition field was also derived from the modified EPA-Clean profile. Table 2-6 lists the modified "EPA-Cle an" boundary, top concentra tion and initial conditions.
The boundary and top conditions were then scaled on a monthly basis by apportioning percentage concentrations of the modified EPA-Clean concentrations. Monthly average concentrations profiles of ambient NO, NOx, O3 and CO were developed for the Costa Mesa air monitori ng station using the 1995 hourly data. (Costa Mesa was selected as being most representative of a co astal boundary site within the Basin). Monthly average profile s of non-methane hydr ocarbon data at Los Angeles were averaged with the Costa Mesa CO profile to characterize the monthly variation in ambient VOC concentrations. For each of the five ambient species, the highest monthly average concentration was de termined and set at a factor of 1.0.Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 14 Each month was apportioned a percentage of the peak month based on the relative observed monthly concentrations . Table 2-7 presents the apportioning factors for the gaseous pollutants. The modified EPA-Cl ean boundary concentrations were then multiplied by the pollutant/monthly apporti oning factors to de velop the monthly profiles.
Preliminary analyses with the modified gaseous boundary conditions revealed that secondary ammonium and nitrate forma tion in UAMAERO-LT model was very sensitive to the boundary and top specifica tion. A final adjustment was made to weight the apportioned monthl y boundary and top conditions by quarter. Winter was weighted by 25 percent, spring and summer by 50 percent and fall by 100 percent.
The particulate pollutant boundary conditi ons at the edges and top of the modeling region remained constant throughout the modeling period . Concentrations of sulfate, ammonium, nitrate and primary part iculates were specified at each boundary based on observational data measured at the San Nicholas Island PTEP site.
A simple vertical pollutant profile was assumed. The boundary cells below the mixing height were given the gridded ground-level polluta nt concentrations, and the concentrations in the boundary cells above this level were assumed equal to their corresponding value at the t op of the modeling domain.
Future Boundary, Top and Init ial Air Quality Conditions
For the future year scenar ios, the boundary, region top and ambient air quality concentrations were adjusted to reflect pr ojected emissions reductions from the 1995 base-year.
Meteorological Inputs
The meteorological data base used by UAMAERO-LT to simulate annual PM 10 and PM 2.5 was derived from the data used in the 1997 AQMP (see Appendix V). Modifications to the winds, temperature a nd humidity fields resulted from the layer averaging from 2 layers to 5 layers. The grea test adjustment in the analysis was made to the mixing height fields in the fo rm of introducing default minimum and maximum mixing profiles.Chapter 2 PM 10 Attainment and Visibility

V - 2- 15

Table 2-6a

Modified EPA-Clean Gase ous Boundary Conditions

Species Units Boundary Top Air Quality NO PPM 0.0005 0.0005 0.0005 NO2 PPM 0.001 0.001 0.001 O3 PPM 0.04 0.04 0.04 NO3 PPM 1.00E-08 1.00E-08 1.00E-08 N2O5 PPM 1.00E-08 1.00E-08 1.00E-08 HONO PPM 0.0001 0.0001 0.0001 HNO3 PPM 0.0001 0.0001 0.0001 PNA PPM 0.00001 0.00001 0.00001 H2O2 PPM 0.0003 0.0003 0.0003 CO PPM 0.2 0.2 0.2 PAR PPM 5.04E-02 4.21E-02 5.04E-02 ETH PPM 1.40E-03 6.00E-04 1.40E-03 OLE PPM 8.28E-04 3.52E-04 8.28E-04 OLE2 PPM 1.00E-08 1.00E-08 1.00E-08 TOL PPM 4.92E-04 3.38E-04 4.92E-04 XYL PPM 2.70E-04 8.89E-04 2.70E-04 ISOP PPM 1.00E-04 1.42E-08 1.00E-04 FORM PPM 5.78E-03 3.80E-03 5.78E-03 ALD PPM 3.97E-03 4.35E-03 3.97E-03 ETOH PPM 1.00E-04 5.00E-08 1.00E-04 MEOH PPM 1.00E-04 1.00E-07 1.00E-04 MTBE PPM 2.00E-08 2.00E-08 2.00E-08 MGLY PPM 1.00E-05 1.00E-05 1.00E-05 OPEN PPM 1.00E-08 1.00E-08 1.00E-08 PAN PPM 1.00E-04 1.00E-04 1.00E-04 CRES PPM 1.00E-05 1.00E-05 1.00E-05 C2O3 PPM 1.00E-05 1.00E-08 1.00E-05 XO2 PPM 1.00E-07 1.00E-08 1.00E-07 ROR PPM 1.00E-07 1.00E-08 1.00E-07 CRO PPM 1.00E-07 1.00E-08 1.00E-07 OH PPM 1.00E-08 1.00E-09 1.00E-08 HO2 PPM 1.00E-07 1.00E-08 1.00E-07 SO2 PPM 1.00E-04 1.00E-04 1.00E-04 HSO4 PPM 1.00E-08 1.00E-08 1.00E-08 CG1 PPM 1.00E-08 1.00E-08 1.00E-08 CG2 PPM 1.00E-05 1.00E-05 1.00E-05 NH3 PPM 1.00E-04 1.00E-04 1.00E-04Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 16 Table 2-6b
Modified EPA-Clean Particulate Boundary Conditions

NH4+ (Fine) μg/m 3 0.8163 0.8163 0.8163 NO3- (Fine) μg/m 3 1.1362 1.1362 1.1362 SO4= (Fine) μg/m 3 1.189 1.189 1.189 SOA1 (Fine) μg/m 3 0.765 0.765 0.765 SOA2 (Fine) μg/m 3 0.765 0.765 0.765 POM (Fine) μg/m 3 0.3 0.3 0.3 EC (Fine) μg/m 3 0.2 0.2 0.2 OTR (Fine) μg/m 3 0.8 0.8 0.8 NH4+ (Coarse) μg/m 3 0.0837 0.0837 0.0837 NO3- (Coarse) μg/m 3 0.4138 0.4138 0.4138 SO4= (Coarse) μg/m 3 0.261 0.261 0.261 SOA1 (Coarse) μg/m 3 0.085 0.085 0.085 SOA2 (Coarse) μg/m 3 0.085 0.085 0.085 POM (Coarse) μg/m 3 0.14 0.14 0.14 EC (Coarse) μg/m 3 000 OTR (Coarse) μg/m 3 2.06 2.06 2.06

Table 2-7
Monthly Apportionment Factors

Month CO VOC NO NO2 O3 Jan 0.67 0.73 0.80 0.58 0.20 Feb 0.61 0.66 0.59 0.79 0.40 Mar 0.33 0.55 0.34 0.58 0.60 Apr 0.22 0.45 0.20 0.37 0.80 May 0.02 0.30 0.02 0.13 1.00 Jun 0.02 0.34 0.03 0.18 1.00 Jul 0.04 0.41 0.02 0.21 1.00 Aug 0.08 0.35 0.03 0.32 1.00 Sep 0.14 0.37 0.07 0.32 0.80 Oct 0.36 0.48 0.28 0.55 0.60 Nov 0.89 0.86 0.80 1.00 0.40 Dec 1.00 1.00 1.00 0.92 0.20Chapter 2 PM 10 Attainment and Visibility

V - 2- 17 Three-Dimensional Temperature and Humidity Fields UAMAERO-LT required gridded three-dimens ional temperature and humidity fields as input for the particulate and gaseous ch emistry. Three-dimensional temperature and humidity fields were developed from the available surface and upper air data using Poisson objective analysis techniqu es. Data from 16 District air monitoring stations and FAA airport obse rvations provided characterization of the daily surface temperature and humidity fiel ds. An additional eight ps eudo-stations were created from this data base to char acterize offshore temperature and humidity profiles and to represent desert and mountain boundary cond itions. The hourly surface fields were subjected to a 5-point filter to smoot h gridded temperatur e variations.
Hourly temperature and humidity profiles through 2000 m aloft were interpolated from the morning (0400 PST) and afternoon ( 1600) coastal soundi ng profile taken at Miramar Naval Air Station (NKX). The gri dded hourly surface fields were merged with the hourly upper level profiles and were vertically averaged by grid to match the five vertical layers determined by the mixing height specification for the UAMAERO-LT simulations.
Use of the 3-dimensional temperature field for the UAMAERO-LT simulations negated the need to specify temperatur e lapse rates above and below the mixing height as required by the U.S. EP A version of the UAM during modeling applications.
Mixing Heights Mixing was calculated usin g a Holzworth (1964) approa ch, which estimates the extent of buoyant vertical lifting of an ai r parcel based on the surface temperature of the air parcel and that of the environmen t lapse rate measured by the morning and afternoon soundings at NKX. The basic pr ocess is summarized in Technical Report V-B of the 1994 AQMP.
The major modification to the mixing calcul ation was to superimpose a set of criteria for adjusting daily minimum, and daily minimum-maximum mixing heights. The criteria are summarized in Table 2-8. The monthly values set for the minimummaximum mixing height in the coastal and mid-basin areas were based on the calculated 1995 daily maximum mixing at Central Los Angeles. The minimummaximum mixing heights ranged from 750 m in the mid-summer months to 850 m in winter and spring. This modification was made to adjust mixing in the low elevation stations when cool surface temperatures observed in the marine modified air restricted the buoyant mixing height calc ulation, yet a define d marine layer was present.Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 18 Table 2-8
Mixing Height Adjustment Criteria

Minimum Mixing Heights

Station/Zone Station Height (Ft) Above Sea Level Mixing Height (m)

Coastal 0-100 150

Mid-Basin 100-500 100

Inland-Basin 600-1700 50

Mountains > 1700 50

Deserts Variable 50 Minimum Assigned Height for Maximum Mixing

Station/Zone Station Height (Ft) Above Sea Level Mixing Height (m)

Coastal 0-100 Monthly Profile Mid-Basin 100-500 Monthly Profile

Inland-Basin 600-1700 Calculated

Mountains > 1700 Calculated

Deserts Variable Calculated

The maximum daily mixing hei ghts were capped at 2000 m. On "rain-days" when 0.01 inches of precipitation was measured in the Basin the mixing was raised to 2000 m for all 24-hours. The final gridded mixi ng height fields were subjected to smoothing with time and space.

Wind Fields The hourly wind fields used by the UAMAE RO-LT were generate d using the Hybrid Diagnostic Wind Model (HDWM) develope d by Douglas and Kessler (1988). The HDWM approach, which incorporates a di agnostic wind algorithm with objective analysis, is described in Technical Report V-B of the 1994 AQMP.
For wind field generation, th e diagnostic model utilized wi nd barriers to assist in characterizing flow through the complex terrain. Winds were generated for a 5 km square grid with 19 vertical layers. Th ree-dimensional winds were generated using the diagnostic assumption coupled with objec tive analysis using all available upper air winds and hourly averaged wind data at the surface.Chapter 2 PM 10 Attainment and Visibility

V - 2- 19 The District surface wind observations, ro utinely monitored at 33 locations, were used to characterize hourly wind fiel ds in the mixed la yer for the annual UAMAERO-LT modeling application. Winds aloft (1500m) were characterized by synoptic winds extrapolated from the daily 0400 and 1600 PST 850 millibar surface analyses. Key upper air locations include d Vandenberg AFB, Sa n Diego, Las Vegas and a mid-basin location, approximately On tario. These upper air wind data were merged with hourly radar wind profiles measured at LAX.
In the preparation of the HDWM input files for the UAMAERO-LT annual model application, the 1500 m synoptic winds were assigned to characterize all layers above 1000 m. Winds between th e surface and the 1000 m level were interpolated from the surface observations using a “power law” profile.
UAM layer-averaged winds were crea ted from the HDWM wind modeling techniques using a layer matching scheme (UAMWND) developed by Douglas et al. (1990), which weights surface layer wind infl uence to layers aloft on the basis of stability. For the UAMAERO-LT annual app lication, winds were averaged into a 5- layer format (two below the mixing hei ght and three above). The 3-dimensional winds were converted to a 5-layer format using the UAM layer-matching scheme and the gridded matrix of hourly mixing heights.
Additional post-processing te chniques were selectively applied to the UAM wind fields generated using one or more of th e above methodologies. These included the use of a 5-point filter to smooth a UAM wi nd field to dampen horizontal shear, and use of a filtering technique [which follows a profile suggested by O’Brien (1970)] to adjust UAM vertical velocities and damp en mass flow through the top of the modeling domain.
Rain Days
Precipitation summaries were reviewed to determine the dates on which measurable rainfall (0.01 inches or more in the South Coast Drainage Division) fell in the Basin during 1995. A total of 56 da ys met this criterion in th e Basin for 1995. Table 2-9 lists the dates meeting this criterion. Th is data was used by the preprocessor to seasonally adjust entrained and wind blow n dust emissions by a rain-factor. The rain-factor adjustment was taken from EPA AP-42 (Fifth Edition, Volume 1) 13.2.1-- Paved Roads. The seasonal rain-factor adju stment was made on a quarterly basis. The rain factor adjustment was applied to all fugitive dust emissions categories. In addition, the photolysis ra te used by UAMAERO-LT was reduced by 40 percent on rain days to account for insola tion reduction due to cloud cover.Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 20 9-Cell Averaging
A nearest cell average of predicted concentr ations is typically used when comparing gridded concentrations to station measurements, because of possible spatial misalignments of the predicted concentr ation fields. The UAMAERO-LT modeling results are presented based on a nearest ni ne-grid-cell average basis. Performance evaluations at each station are based on this average concentration.

Table 2-9
1995 Rain Days in the Basin: Days Recording Measurable Precipitati on of at least 0.01 Inches of Rain

Month Dates January 3, 4, 5, 7, 8, 9, 10, 11, 12, 13, 15, 16, 17, 21, 23, 24, 25, 26 February 8, 9,13, 14,15 March 2, 3, 4, 5, 6, 7, 10, 11, 12, 21, 22, 23, 24 April 16, 17, 18 May 14,15, 22, 23, 24 June 1, 15, 16, 17 July 16 September 1, 2 October 31 November 1 December 13, 14, 16, 23, 24



### Linear Rollback For 24-Hour Av erage Maximum Concentrations
Linear rollback on particulate component sp ecies is used to assess future year 24- hour maximum PM 10 concentrations at the five PTEP monitoring sites. Observed 24- hour average maximum PM 10 for 1995 are used to anchor the ro llback calculation for future year impacts. For Rubid oux, the 1995 annual second maximum PM 10 concentration (206 μg/m 3 ) is used for the analysis si nce the peak 24-hour average (219 μg/m 3 ) occurred during “Santa Ana” high wind s. This day, (April 9, 1995), has not been tagged as a natural event in the AIRS data set since the policy did not take effect until 1997. (The pr imary portion of the PM10 mass sampled at Rubidoux on April 9, 1995 was 192 μg/m 3 , or 88 percent of the total). It is useful to note that the 24-hour PM 10 standard has been exceeded on only 16 days since 1995 with 10 of those days having high winds. In addition, since 1997, only high wind conditions have caused the 24-hour st andard to be exceeded.Chapter 2 PM 10 Attainment and Visibility

V - 2- 21 The methodology used to c onduct the linear rollback calculations is described at length in Appendix V of the 1997 AQMP. Briefly, the lin ear rollback approach used to predict component partic ulate concentrations for 2006 and 2010 assumes that the ambient concentrations above background le vels are directly proportional to the different emissions species in the inventor y. In mathematical terms, the rollback relationship can be written as follows:

C p = [(C b - k) • Q p /Q b ] + k

where C p and C b are the future year and baseline PM 10 component concentrations (e.g., sulfate), respectively; Q p and Q b are the future year and baseline PM 10 component emission rates (e.g., sulfur di oxide), respectively; and k denotes the global background PM 10 component concentration (e .g., sulfate). For most PM 10 components it is assumed th at global background concentrations are negligible; therefore the above equation simplifies to

C p = C b • Q p /Q b.
The rollback calculation is condu cted on each individual sp ecies. The net rollback is the summation of the individual predicted changes.



### EMISSIONS INVENTORY
The UAMAERO-LT model requires seve ral emissions, aerometric, and meteorological data inputs. These input data are similar to those needed for the UAM ozone simulations. The ozone simula tion requires day-specific emissions inventories, which account for variations in observed diurnal traffic patterns and large source emissions profiles. UAM AERO-LT model is based on the annual average inventory, with adjustments made for weekly and monthly variations. A brief characterization of the annual day emissions used for the UAMAERO-LT modeling analysis follows. An extensive discussi on of the overall emissions inventory is summarized in the 2003 AQMP Appendix III.
The 1997 emissions inventory was backcasted to 1995 to establish an inventory for the base year UAMAERO-LT modeling appli cation. The 1995 emissions inventory is summarized in Table 2-10, along with projected baselin e inventories for the years 2006, and 2010. Also presented in Table 2-10 are the inventories reflecting implementation of the control strategy for 20 06, and two options for control in 2010. Annual average day emissions are presen ted for six categorie s: volatile organic compounds (VOC), oxides of nitrogen (NO x ), oxides of sulfur (SO x ), diesel particulates (Diesel), geological partic ulates (Geologic), and total primary PM 10 (Primary).Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 22 A seasonally based biogenic emissions inve ntory (not listed in Table 2-10) was developed by the California ARB. The inve ntory was temperature corrected for both winter and summer profiles. The summer biogenic inventory was used from April through September. The winter inventor y was used for the remaining months.
Where applicable, point, area and off-road mobile sources we re adjusted to a day-ofweek through-put profile consisting of a Monday-Friday, Saturday and Sunday schedule. On-road mobile sources were also adjusted by th e same day-of-week schedule and overlaid with average diurna l profiles that represent weekday and weekend defined traffic patterns. The on- road mobile source emission data incorporate month specific ambient temperature and humidity input.

Emissions Uncertainties

Uncertainties can be estimated for all source s of emission: point, mobile, and area. With regard to PM10 predic tion, quantification, spatial allocation and apportionment of dust sources is magnified. The followi ng sections address uncertainties selected estimated of PM10 dust emissions.

Paved Road Dust

Paved road dust accounted fo r the largest percentage of the primary emissions category. In addition, the pa ved road dust emissions are a function of VMT. In the 1997 and 2003 AQMP, paved road dust emissions used in the UAM/LC runs were adjusted to reflect a cap on emissions gr owth for high VMT road types in future years. Base year emissions were not cappe d at a given VMT level. The future year adjustment assumed that th e silt loading would be depleted by the entrainment from the traffic volume. Increas ing the traffic volume beyond a set point would not increase dust entrainment because the silt woul d be essentially depl eted. Analysis of model results indicate the paved road dust ma y be overestimated by a factor of two in Los Angeles and Orange Counties where the traffic volume is greatest. The overestimation is lower in Riverside and Sa n Bernardino Counties. Overestimation is also evident in grids having multiple freeways or large thoroughfares. This indicates that emissions may cease to be a function of VMT at lower VMT le vels than used in the base year estimations.Chapter 2 PM 10 Attainment and Visibility

V - 2- 23 TABLE 2-10 UAMAERO-LT Annual Average Day Em issions Inventory (Tons/Day)

Year VOC NO x SO x Diesel Geol Primary (a) Baseline
1995 1306.7 1440.1 107.9 23.8 236.8 313.5
2006 689.2 942.7 59.5 19.9 203.5 291.9
2010 614.7 771.0 60.1 17.5 209.9 298.3
(b) Controlled
2006 673.8 935.4 57.3 19.9 203.5 290.8 2010 Option–1 294.9 543.0 58.9 12.1 209.9 290.6 2010 Option-2 298.4 611.0 58.9 13.8 209.9 292.5

A modeling sensitivity run was conducted to assess the paved road dust contribution to predicted PM10 by eliminating pave d road dust emissions and comparing predicted annual concentrations to those fo r a parallel run having paved road dust. Paved road dust emissions are approximately 50 percent of all PM10 emissions in the Basin. In Los Angeles Coun ty, the average paved road dust contribution to PM10 was 9.9 μg/m 3 or 55 percent of the average predic ted concentration other category. The average value for Orange county was 9.4 μg/m 3 or 58 percent of the predicted other category concentration. In contra st, the paved road dust contributions to Riverside and San Bernardino Counties were 6.4 and 8.3 μg/m 3 or, 33 and 34 percent of the predicted other category concentration, respectively. The 1995 measured annual average concentrations for the other category from Central Los Angeles and Anaheim were 13.0 μg/m 3 and 13. μg/m 3 , respectively. In the sensitivity analysis, the predicted paved road dust contribution to the others category for those sites was 12.5 μg/m 3 for Anaheim and 12.6 μg/m 3 at Central Los Angeles. The regional background concentration fo r the others category is approximately 8 μg/m 3 , (see San Nicholas Island in Figure 2.2 ). The results of the sensitivity analysis indicate that the relative percentage co ntribution from paved road dust to the predicted primary "others" category is si gnificantly higher than the 50 percent weighting the paved road dus t has to the total inventor y and may be more than doubled the actual loading.
Unpaved Road Dust

Uncertainties exist in determ ining both total unpaved road dust emissions and their location (c.f. CARB’s emission methodology, Section 7.10, “Unpaved Road Dust”).Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 24 Regional estimates are based on relativel y broad assumptions of miles of unpaved road miles (e.g. 1989 Caltran s data) and trip activity (e.g ., 10 ADT). Such estimates likely overestimate unpaved road emission s in the western Basin (e.g., more development and paving projec ts in recent years) and u nderestimate emissions in the eastern Basin (e.g. fewer 1989 Caltrans- maintained roads in previously lower population areas). In add ition, the spatial distribu tion of unpaved roads is problematic. Common surrogates, such as population, may not be appropriate in certain subregions. As noted by CARB, better mileage information could possibly be obtained from GIS-based maps, especially for subregions. C oupled with traffic counts on key roads, a better subregional i nventory could be developed, if necessary.
Fugitive Wind Blown Dust
Fugitive wind blown dus t emissions were a nother source of emi ssions uncertainty. Uncertainties occur in the emission estimation methodolo gy, spatial allocation and in the inability of the annual average day to ac curately incorporate the impacts of highwind events. The original fugitive dust emissions are de fined as annual average day county total. The emissions were alloca ted by pastureland acr eage based on a GIS apportionment of dust to areas of each county designated as pastureland in the Basin. This allocation may have reduced the windb lown dust contribution to the Rubidoux area shifting a majority of the Riverside County dust towards the Perris and Hemet areas. For the Mojave Desert Air Basin po rtion of San Bernardi no County, the wind blown dust allocation forced a significant am ount of dust emissions into a limited number of grid cells. Similarly, there was a significant amount of uncertainty associated with gridded allocation of win dblown dust from unpaved roads. A similar cluster of "hot" grid-cells appears in th e Mojave Desert, north of the Cajon Pass.
The impact of "Santa Ana" high wind events on the fug itive windblown dust emissions cannot be well simulated through the annual modeling. Wind trajectories are highly localized and may impact one ar ea more than another. A classic case occurred on April 9, 1995 at Rubidoux where 24-hour averag e concentrations measured 219 μg/m 3 under strong Santa Ana winds. Sulfate, nitrate and chloride accounted for 11 percent of the mass while the majority of the remaining mass (195 μg/m 3 ) fell into the primary (others) category. The total mass observed on this day accounts for 3.6 percent of th e annual average, mostly due to high wi nds. On the same day, the neighboring sites of Norco an d Ontario measured 24 -hour averages of PM10 of 64 and 66 μg/m 3 respectively. These values are roughly one third of the Rubidoux concentration. The capricious na ture of wind blown dust, demonstrated through the PM10 concentrations measured on April, 9, 1995 , is summarized in Table 2-11.Chapter 2 PM 10 Attainment and Visibility

V - 2- 25 TABLE 2-11 PM10 Concentrations Observed on Apr il 9, 1995 During Santa Ana Winds
Location 24-Hour Average (μg/m 3 ) % of Annual Average
Fontana 89 0.8

Norco 64 0.4
Ontario 66 0.4

Perris 145 3.6
Rubidoux 219 3.6
Redlands 124 2.7
San Bernardino 128 2.1

The local siting of the Rubidoux monitori ng station and land use within 5 km grid further accentuate the uncerta inty of the windblown du st estimated emissions. Figures 2-6 and 2-7 provide an aerial close-up of the mon itoring site and an overview of the Rubidoux grid. Throughout th e 1990's until 2002, the Rubidoux site was located on a open field with access via a di rt road. The neighboring lots supported horse husbandry operations. Fugitive dust emission from the local setting are not accurately captured by the distribution surrogate.
From the expanded view, (Fig ure 2-7) it is evident that there are off-road fugitive dust sources (dirt biking and 4- wheel trafficking) on the el evated terrain to the north of the monitoring site. Additional poten tial primary dust emissions sources arise from the riverbed of the Santa Ana River to th e east of the site. In general, the river bed is mostly dry during the second half of the year le nding to enhanced potential dust emissions in the third and fourth quarters.Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 26 Figure 2-6 Rubidoux Air Monitoring Station a nd Immediate Surrounding Area

Construction Dust

The location of PM10 emissions from constr uction activities presents a third area of uncertainty to the analysis. The surrogate used to allo cate 1995 Basin construction dust emissions was the number of building permits issued by individual cities, within each of the four counties. The building permit su rvey was based on construction year 2000. The assumption was made that th e cities and relative numbers of permits issued were consistent between 1995 and 2000. The estimated countywide emissions were apportioned by city and the dust emis sions were uniformly distributed within the city's geographical boundaries. While this methodology brought the construction dust emissions closer to the actual activitie s, the spatial resolu tion within each city was still coarse whereby neig hboring grids woul d be underestimat ed and others overestimated. In addition, the assu mption that 2000 direc tly represented 1995 introduced additional uncertainty. Rubidoux Monitoring StationChapter 2 PM 10 Attainment and Visibility

V - 2- 27 Figure 2-7 Rubidoux Air Monitoring Station a nd Immediate Surrounding Area

The uncertainty of the construction dust em issions is clearly evident at the Fontana air monitoring site in 1995. In October 1995, construction began on the California Speedway. The construction site was approx imately one square mile in area and was located one kilometer upwind of the Fontana monitoring s ite. Figure 2-8 presents the locations of the California Sp eedway and the Fontana mon itoring site. Based on the project's environmental impact report, af ter mitigation actions, dust emissions from the project were estimated at 1,450 kg per day. Using EPA's ISCST point source dispersion model and an annual meteorolog ical data set for Fontana, a potential quarterly impact from the construction grad ing operations was estimated to be 5.2 μg/m 3 , or 1.3 μg/m 3 to the annual average. Thes e emissions and projected impacts were not captured by the spatial and te mporal allocation of the construction emissions. As a consequence, it is expected that the primary prediction would be under represented by the regional m odeling analysis for the base year. Rubidoux Monitoring StationFinal 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 28 Additional uncertainty is introduced fo r the future baseline emissions where projections of population growth, employmen t and population density, were used to apportion construction dust.

Figure 2-8
Fontana Air Monitoring Station and Immediate Surrounding Area



### BASE-YEAR SIMULATIONS

UAMAERO-LT was run for the 1995 base si mulation using the annual average day emissions presented in the previous emission inventory discussion and the meteorological and air quality data inputs outlined in the preceding section. EPA guidance focuses model perfo rmance to the ability to pr edict the PM10 component species and the total mass. Three elements are presented in this section to address model performance guidance and quantify th e base-year performance: (1) the PM10 component species perfo rmance evaluation for the PTEP sites, (2 ) the annual average Fontana Monitoring StationChapter 2 PM 10 Attainment and Visibility

V - 2- 29 performance evaluation for tota l mass at the SSI PM10 sites, and (3) the analysis of the 1995 gridded simulation.


### PM10 Component Species Performance Evaluation for the PTEP Sites
The UAMAERO-LT 1995 base-year PM10 annual average pr edicted PM10 and observations for the six compon ent species at the five Basi n PTEP sites are presented in Table 2-12. In general, ammonium is we ll predicted at all sites. Nitrate tends to be over predicted at most sites with the exception of Rubidoux. In contrast, the simulation tends to under predict sulfate and elemental carbon at all sites but the concentration differential is typically 2 μg/m 3 or less. Los Angeles and Anaheim clearly exhibit over prediction of mass in the primary category, most likely due to uncertainties in the paved road dust emission inventory. Fontana and Rubidoux are under predicted in the primary category due to uncertainties in the allocation of the fugitive dust, farming operation dust and construction dust categories.

TABLE 2-12 UAMAERO-LT 1995 Base Year Model Predictions (μg/m 3 ) Compare to Annual Average Observations (μg/m 3 )

Anaheim Diamond Bar Fontana Los Angeles Rubidoux Component
Predicted Observed Predicted Observed Predicted Observed Predicted Observed Predicted Observed

Ammonium 4.5 4.0 4.8 4.6 5.7 4.6 4.0 4.0 6.2 5.9

Nitrate 13.6 10.4 15.2 11.8 17.2 13.4 11.8 9.9 18.9 17.5

Sulfate 2.8 4.8 2.6 4.3 3.3 3.6 2.7 4.3 2.8 4.0

Organic Carbon 6.9 7.4 6.6 8.6 6.4 10.4 7.2 8.5 7.0 10.5

Elemental Carbon 2.2 2.9 1.9 3.5 2.2 3.7 2.3 3.6 2.6 3.1

Primary 19.5 13.8 16.7 13.1 20.0 25.2 20.8 13.0 19.3 27.8

Total Mass 49.5 43.5 47.8 46.0 54.8 61.0 48.8 42.8 56.8 69.0Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 30 

### UAMAERO-LT Component Species Model Performance Evaluation
Draft Working Paper #M-2, “PM 10 Modeling Protocol for the 1997 Air Quality Management Plan Revision” (Zhang et.al.,) outlines a series of performance goals that were established to estimate the ability of the UAMAERO-LT to recreate annual PM 10 . The performance goals express average pr ediction error over the five sites for each of the componen t species. Table 2-13 su mmarizes the UAMAE RO-LT annual performance goals.
The performance statistics for the UAMAERO -LT 1995 base case annual simulation are presented in Table 2-14. Percent prediction error is presented for each component species at the five Basin PTEP sites.

TABLE 2-13
UAMAERO-LT Performance Goals

Species Goal (%) Comparison Basis
Sulfate ± 30 Annual Average Nitrate ± 30 Annual Average Ammonium ± 30 Annual Average Primary ± 30 Annual Average

Overall, the performance of the UAMAERO-LT averaged over the five stations is within or near the goals defined in Table 2-13. Predictions of ammonium and nitrate were within the 30 pe rcent error performance criteria at all stations for the base case application. The five station average erro r for ammonium, nitrate and organic carbon were 9.7, 23.7, and 23.4 pe rcent, respectively. Percentage errors for sulfate prediction at Anaheim, Diamond Bar, Lo s Angeles and Rubidoux exceeded the 30 percent threshold. When taken collectively, the five station average is calculated at 33.9 percent. This statis tic is somewhat misleading however since the annual average concentrations of sulfates measured at each of these sta tions were less than 5.0 μg/m 3 , and bias in the prediction performa nce was typically less than 2.0 μg/m 3

. A similar observation can be made for elemental carbon.
Percent errors for primary particulates at Anaheim, and Los Angeles reflect uncertainties in the gridded primary particulate emissions inventory for the more urbanized western half of the Basin. Perc entage errors in prediction performance atChapter 2 PM 10 Attainment and Visibility

V - 2- 31 Diamond Bar, Fontana and Rubidoux, stations located in the easter n half of the Basin that experience greater, and more frequent, primary emissions impacts, meet or are close to the goals set for model performance.
Figures 2-9 through 2-13 present sca tter plots of predicted and observed concentrations of the six components. In the figures, the 30 percent error bars are drawn on each side of the unity line. On ly a few predictions in the nitrate category are beyond the 30 percent error bounds with most of the predictions for the other components falling with in bounds. Figures 2-14 thr ough 2-18 depict the time series of predicted 24-hour average total and observ ations for each of the six components at each PTEP site. What is evident from the scatter plots and the time series analyses is that the model responds to changes in daily meteorology and captures the seasonal variation of particulate forma tion. The simulation is poorest in the first quarter during rapid transitions between rain events. Ot herwise, component concentrations tend to follow observations with the peak concentrations (predict ed and observed) occurring the fall.

TABLE 2-14 UAMAERO-LT Performance Statistics (annual percent absolute error)

Species Location Ammonium Nitrate Sulfate Organic carbon Elemental carbon Primary

Anaheim 12.5 29.5 42.9 6.7 24.1 40.3 Diamond Bar 4.3 28.8 39.5 23.3 45.7 27.4 Fontana 23.9 28.3 8.3 38.5 40.5 20.9 Los Angeles 2.6 21.6 35.7 15.3 37.8 63.8 Rubidoux 5.1 10.3 30.0 33.3 18.8 30.8 Average 9.7 23.7 31.3 23.4 33.4 36.6



### Annual Average SSI Mass Pe rformance Evaluation
As part of the weight of evidence discussion, the base-y ear performance evaluation is presented for the UAMAERO-LT simulation comparing the predicted and observed annual average mass at the District's SS I monitoring network and at SSI sites in neighboring air basins included in the modeli ng domain. The goal of this analysis is to demonstrate that the model is capable of simulating PM10 not only at the key sites but across the modeling domain. Ta ble 2-15 summarizes the UAMAERO-LT performance for annual average mass at th e SSI sites. Figures 2-19 through 2-21Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 32 provide the time series of the 24-hour averaged predicted PM10 and observed mass at the SSI sites.
With the exceptions of Bann ing and Crestline, the simula ted annual average PM10 concentrations fall with the 30 percent goal at all Basin SSI s ites. It is important to note that the station predictions represent a nine-grid cell average. In general, the east Basin sites tend to be under predicted w ith the notable exceptions of Ontario and Pomona/Diamond Bar. The remaining Los An geles County sites are mixed with a slight bias towards over prediction. Th e two Orange County sites are over predicted by an average of 24 percent.

Table 2-15

UAMAERO-LT Predicted and SSI Observed 1995 Base-Year Annual Average PM 10 Concentrations

Location Predicted Annual Average Concentration (μg/m 3 ) Observed Annual Average Concentration (μg/m 3 ) Percentage Prediction Error Central LA 48.6 42.8 13.6 Hawthorne 34.0 36.2 -6.1 N. Long Beach 46.3 38.7 19.6 Burbank 45.0 42.2 6.6 Azusa 44.4 49.1 -9.6 Pomona/Diamond Bar 47.2 46.0 2.6 Santa Clarita 41.8 37.0 13.0 Anaheim 49.5 43.5 13.8 El Toro 46.2 37.6 22.9 Norco 57.3 54.2 5.7 Rubidoux 56.5 69.0 -18.1 Perris 45.4 46.7 -2.8 Banning 21.3 30.1 -29.2 Ontario 60.7 54.0 12.4 Fontana 54.8 61.0 -10.2 San Bernardino 52.9 57.3 -7.7 Redlands 40.5 48.4 -16.3 Crestline 43.5 20.4 113.2 Thousand Oaks 36.7 27.0 35.9 Simi Valley 39.3 28.0 40.4 Piru 26.9 27.0 -0.4 Lancaster 17.8 25.6 -30.4 Hesperia 60.4 14.0 331.4 Victorville 57.7 12.0 380.8Chapter 2 PM 10 Attainment and Visibility

V - 2- 33 FIGURE 2-9
Predicted and Observed 24-Hour Average PM 10 AnaheimFinal 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 34 Figure 2-10

Predicted and Observed 24-Hour Average PM 10 Central Los AngelesChapter 2 PM 10 Attainment and Visibility

V - 2- 35 Figure 2-11

Predicted and Observed 24-Hour Average PM 10 Diamond BarFinal 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 36 Figure 2-12

Predicted and Observed 24-Hour Average PM 10 FontanaChapter 2 PM 10 Attainment and Visibility

V - 2- 37 Figure 2-13

Predicted and Observed 24-Hour Average PM 10 RubidouxFinal 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 38 Figure 2-14

Time Series of Predicted an d Observed 24-Hour Average PM 10 AnaheimChapter 2 PM 10 Attainment and Visibility

V - 2- 39 Figure 2-15

Time Series of Predicted an d Observed 24-Hour Average PM 10 Central L.A.Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 40 Figure 2-16

Time Series of Predicted an d Observed 24-Hour Average PM 10 Diamond BarChapter 2 PM 10 Attainment and Visibility

V - 2- 41 Figure 2-17

Time Series of Predicted an d Observed 24-Hour Average PM 10 FontanaFinal 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 42 Figure 2-18

Time Series of Predicted an d Observed 24-Hour Average PM 10 RubidouxChapter 2 PM 10 Attainment and Visibility

V - 2- 43 Figure 2-19

Time Series of Predicted an d Observed 24-Hour Average PM 10 at SSI SitesFinal 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 44 Figure 2-20

Time Series of Predicted an d Observed 24-Hour Average PM 10 at SSI SitesChapter 2 PM 10 Attainment and Visibility

V - 2- 45 Figure 2-21

Time Series of Predicted an d Observed 24-Hour Average PM 10 At SSI SitesFinal 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 46 

### 1995 UAMAERO-LT Grid-Cell Performance Evaluation
Figure 2-22 presents the grid cell predicte d annual average PM10 predictions for the 1995 base-year. As demonstrated from the predicted and observed SSI station analysis, grid cell based simulation demonstrat es a west to east gradation in predicted PM10 with Basin peak predicte d annual average concentra tions coinciding with the areas defined by the SSI data depicted in Figure 2-4.
Noted in the analysis are several grid cells exhibiting high "hot -spot" values of PM10 in areas where predicted particulate levels are estimated to be above the regional profile. The primary areas of over predictio n occur in the San Fernando Valley (an area dominated by paved road and construction dust em issions) and in the Basin portions of San Bernardino and Riverside Counties (where wind blown fugitive dust is added to constr uction and paved road dust impacts).
Additional "hot-spot" grid cells are identif ied in the Corona, Chino, Ontario and Fontana-Rialto areas of Riverside and th e Basin portion of San Bernardino Counties. The impacts of the "hot spot" grid cells on the future year PM10 predictions and the uncertainties of the primary emissions in thos e grid cells are addressed in a following section.

Figure 2-22

1995 UAMAERO-LT Grid-Ce ll Performance Evaluation (Grid Cell Predicted Concentrations in μg/m 3 )Chapter 2 PM 10 Attainment and Visibility

V - 2- 47 

### PM2.5 Component Species Performan ce Evaluation for the PTEP Sites
The UAMAERO-LT 1995 base-yea r annual average predicted PM 2.5 and observations for the six compon ent species at the five Basi n PTEP sites are presented in Table 2-16. In general, ammonium is well predicted at most sites with Fontana being under predicted. Nitrate tends to be over predicted at most sites with the exception of Rubidoux. In contrast, the simulation tends to under predict sulfate, organic carbon and elemental carbon at all sites but the concentration differential is typically 2 μg/m 3 or less. PM 2.5 mass in the primary category is clearly over predicted at all sites. The over prediction in the primary category tends to offset the under prediction in sulfate, organic carbon and elemental carbon. The net result is for a close prediction of total PM 2.5 mass at all site exce pt Anaheim .

TABLE 2-16
UAMAERO-LT 1995 Base Year PM 2.5 Model Predictions (μg/m 3 ) Compare to Annual Average Observations (μg/m 3 )

Anaheim Diamond Bar Fontana Los Angeles Rubidoux Component

Predicted Observed Predicted Observed Predicted Observed Predicted Observed Predicted Observed

Ammonium 4.2 4.3 4.2 4.6 5.1 4.7 3.3 3.9 5.2 6.1

Nitrate 10.6 8.2 10.9 9.3 12.5 10.8 8.0 7.5 13.3 14.7

Sulfate 2.3 4.2 2.1 4.0 2.7 3.8 2.1 3.7 2.1 3.2

Organic
Carbon 5.1 6.2 4.4 6.4 4.7 7.2 4.9 6.5 4.9 6.4

Elemental Carbon 2.0 2.7 1.7 3.3 2.0 3.3 1.9 3.4 1.9 2.8

Primary 5.8 0.7 5.1 0.1 6.5 2.0 5.8 0.1 5.5 2.6

Total Mass 30.0 26.3 28.4 27.7 33.4 31.8 26.0 25.1 33.0 35.8



### FUTURE AIR QUALITY
Future-year PM 10 air quality is projected using the procedures and assumptions previously described. Em issions for the 2006 and 20 10 baseline and controlled scenarios are listed in Table 2- 10.Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 48 The federal annual average PM 10 standard is 50.4 μg/m 3 , and it is calculated as an annual arithmetic mean; th e federal 24-hour average PM 10 standard is 150 μg/m 3

. The state PM 10 air quality standards are st ricter than the federal PM 10 standards. The state annual PM 10 standard is 20 μg/m 3 (also based on an annual arithematic mean), and the state 24-hour average PM 10 standard is 50 μg/m 3 . There is no requirement to comply with the state PM 10 standards by a specified da te. However, future-year annual average PM 10 concentrations show the progre ss toward the attainment of the state PM 10 air quality standards.

The UAMAERO-LT simulation w ith emission controls show s that the Basin will attain the annual federal PM 10 standard by the year 2006. In addition, linear rollback with emission controls show that the Basi n will attain the 24-h our average federal PM 10 standard by the year 20 06. However, the analysis indicates that the more restrictive state annual and 24-hour average PM 10 standards will not be met in all areas of the Basin by 2010.
The future year PM 10 discussion follows the order of the previous analysis on base year model performance evaluation. Future year PM 10 is presented for: (1) the PM10 component species at the PTEP sites, (2) the annual averag e for total mass at the SSI PM10 sites, and (3) th e 2006 gridded simula tion and weight of evidence "hotspot" grid analysis.
For the purpose of the Basin attainment de monstration, analyses of predicted PM10 outside the District jurisdiction are not presented in this draft analysis.



### PM 10 

### Control Strategy

The PM 10 control strategy is component of the overall control strategy presented in Chapter 4 of the 20 03 AQMP. Aside fro m directly emitted PM 10 , emissions reductions for VOC, NOx and ammonia are required to bring the Basin into compliance of the annual av erage and 24-hour average st andards by the year 2006 and maintain those standards in 2010. Th e majority of the VOC and NOx emissions reductions projected by 2006 come from im plementation of measures in the mobile, point and area sources categories and fl eet turnover. The 19 97 AQMP introduced several control measures to reduce dire ctly emitted PM10, and address VOC and ammonia emissions from agricultural operati ons that will impact 2006 emissions. The 2003 AQMP Short-Term strategy contin ues the implementations of several measures that were introduced in the 19 97 AQMP. These measures address PM10 VOC and ammonia emissions from livesto ck waste (WST-01), composting (WST02) restaurant operations (PRC-03), and emissions reductions from petroleum fluid catalytic cracking units (CMB-09). Newly pr oposed control measures include further reduction to fugitive dust sources (BCM -07), further emission reduction from aggregate cement plant manufacturing opera tions (BCM-08), emissions reductionsChapter 2 PM 10 Attainment and Visibility

V - 2- 49 from miscellaneous ammonia sources (MSC -04), emissions reductions from wood burning fireplaces and wood stoves (MSC-06 ), and further emissions reductions from in-use off-road vehicles and equipment (FSS-06).



### PM 10 

### in the Year 2006

Annual PM 10 By Component Specie s for the PTEP Sites
The annual average PM 10 concentrations in the year 2006 for each co mponent species category with and without emission controls are shown in Table 2-17. With and without controls, the entire Basin will attain the federal annual average PM 10 standard by the year 2006. The state annual average PM 10 air quality standards will not be met at any site by the year 2006 , even with the im plementation of emission controls.

Table 2-17
Annual Average PM 10 Concentrations (μg/m 3 ) in the Year 2006

Anaheim Diamond Bar Fontana Los Angeles Rubidoux Component Without Control With Control Without Control With Control Without Control With Control Without Control With Control Without Control With Control
Ammonium 4.0 3.9 3.6 3.6 4.4 4.3 2.9 2.9 4.4 4.2

Nitrate 10.9 10.9 10.7 10.6 11.8 11.7 7.8 7.8 12.1 11.9

Sulfate 3.1 3.1 2.7 2.6 2.7 3.6 2.4 2.4 3.1 2.8
Organic Carbon 6.9 6.9 5.5 5.5 5.7 5.7 5.6 5.6 6.6 6.6

Elemental Carbon 2.6 2.6 2.0 2.0 2.6 2.6 1.9 1.9 2.7 2.5
Primary 22.6 22.5 15.7 15.6 19.3 19.2 17.6 17.5 20.2 19.5

Total PM 10 50.2 49.9 40.2 39.9 47.5 47.2 38.2 38.0 49.0 47.6

Annual PM10 By Total Mass at the SSI Sites

Table 2-18 summarizes the UAMAERO- LT predicted annual average PM10 concentrations in the year 2006 for the baseline and controlled emissions at the 18 SSI sites. Without controls , 17 of the 18 sites in th e Basin will meet the federal annual average PM10 standard. Only Ontario is projected to exceed the standard. With the control strategy fully implemente d all sites will meet the federal annual average standard.Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 50 UAMAERO-LT Grid-Level Simulati on: 2006 Controlled Emissions
Figure 2-23 presents the 2006 UAMAERO-LT grid-level analysis for the controlled emissions scenario. With controls in plac e, all but 13 grid cells in the Basin are projected to have annual concentrations that will meet the federal standard. Five of the grid cells are located in Los Angeles and Orange counties in areas that experience heavy traffic and are impacted by paved road dust. One grid cell is located on the Basin boundary (in LA County near Acton) that appears to have emissions (from controlled burning activities) that are impr operly distributed. The remaining seven grid cells are located in Basin portions of San Bernardino and Riverside Counties in areas heavily impacted by fugitive wind blow n dust, construction dust and paved road dust.
The following section provides a weight of evidence discussion addressing the uncertainties in the primary dust emissions and their impact to the grid-level UAMAERO-LT 2006 future y ear PM10 prediction.

Table 2-18
UAMAERO-LT Predicted Annual Average PM 10 Concentrations for Each SSI Site

Location 2006 Baseline Predicted Annual Average Concentration (μg/m 3 ) 2006 Controlled Predicted Annual Average Concentration (μg/m 3 ) 2006 Controlled Percentage of State Standard

Central LA 38.2 38.0 194

Hawthorne 29.6 29.3 147 N. Long Beach 42.7 42.2 211

Burbank 35.3 35.1 176

Azusa 37.1 37.0 185

Pomona/Diamond Bar 40.2 39.9 200

Santa Clarita 36.8 36.7 184

Anaheim 50.2 49.9 250

El Toro 41.9 41.5 208

Norco 46.0 45.7 229

Rubidoux 49.0 47.6 238

Perris 38.7 38.4 192 Banning 18.1 18.0 90

Ontario 50.9 50.2 251

Fontana 47.5 47.2 236

San Bernardino 47.0 45.8 229

Redlands 33.8 33.4 167

Crestline 39.0 38.4 192Chapter 2 PM 10 Attainment and Visibility

V - 2- 51 Figure 2-23

UAMAERO-LT Grid-Level Simulati on: 2006 Controlled Emissions (Grid Cell Predicted Concentrations in μg/m 3 )

2006 UAMAERO-LT Hot Spot Grid Weight of Evidence Analysis
Figure 2-24 presents the 2006 UAMAER O-LT grid-level simu lation depicting only the 13 "hot spot" grid cells. Table 2-19 lists the individual grids that had concentrations predicted by UAMAERO-LT th at exceeded the fe deral standard for the 2006 controlled emissions scenario. Model predictions for the six species categories and total mass are presented. Th e Grids are sorted ge ographically into three general sub regions: LA-Orange Co unties and Riverside-Ba sin San Bernardino Counties. Table 2-20 lists the ARB specified PM10 emissi ons source categories that were the major contributors to PM10 in the "hot spot" grid cells. Tables 2-21 through 2-22 present the top contributing PM 10 emissions categories for each grid in the three groupings of cells.
In the L.A.-Orange Counties grouping the federal standard is predicted to be exceeded by a maxi mum of 4.1 μg/m 3 (with the exception of grid cell [21,32] which is discussed later). The "other" or primar y category is predicte d to be between 19.8 and 24.7 μg/m 3 , an average of 22.3 μg/m 3 . The average predicted primary contribution in these gr ids is roughly 7 μg/m 3 higher than the av erage observed primary component measured in 1995 at the Central L.A. and Anaheim PTEP sites.Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 52 Figure 2-24
UAMAERO-LT "Hot Spot" Grid Ce lls: 2006 Controlled Emissions (Grid Cell Predicted Concentrations in μg/m 3 )
As presented in Table 2-21 the major c ontributing emissions s ource categories to L.A.-Orange Counties grouping are paved ro ad dust, constructi on dust and off-road construction diesel equipment. Given that paved road dus t on average contributed at least 9 μg/m 3 to the primary category and that th e emissions are estimated to be doubled the actual for this area of the Basin. As a consequence, it is most probable that with accurate emissions estimate of paved road dust, the predicted annual average concentrations w ould be at least 4.5 μg/m 3 lower and would meet the federal standard. Uncertainties in the placement of constructio n dust and off-road equipment emissions most likely would lower th e predicted concentration further.
Projected 2006 PM10, VOC, NOx and CO emissions for all of L.A. County's waste burning and disposal through forest mana gement were inappropriately specified through a surrogate to grid cell (21,32). This accounts for the high predicted concentrations of primary, elemental car bon and organic carbon. The emissions should have been distributed over several grid cells in the Angeles National Forest, in areas with limited traffic, c onstruction or other source of emissions. With the proper allocation of emissions, cell (21,32) would most likely meet the federal standard.Chapter 2 PM 10 Attainment and Visibility

V - 2- 53 Table 2-19

2006 UAMAERO-LT Predicted Hot Spot Grid Cells

Grid Predicted Mass (μg/m 3 ) XX YY NH4 NO3 SO4 OC EC OTHER TOTAL L.A.-Orange Counties 18 24 4 11.6 2.9 7.1 2.6 22.3 50.5 21 32 2 6.8 2.3 25.5 9.3 15.4 61.3 23 15 6.1 8.6 10.5 5 4.8 19.8 54.8 29 15 3.9 10.6 3.3 7 3.3 24.2 52.2 29 16 4 11.1 3.1 7.2 2.7 23.1 51.2 30 15 4 11.5 3 7.2 2.5 24.7 53 Riverside-Basin San Bernardino Counties 35 20 4.8 12.4 4.2 6.7 2.8 21.6 52.4 36 16 4.4 12.7 2.9 6.4 7.7 31.9 65.9 36 19 4.9 13 3.8 6.5 3.1 21.4 52.7 36 20 5.5 12.5 6 6.6 4.9 27.9 63.4 36 21 5.3 11.5 6.4 5.5 3.6 20.8 53 37 17 4.4 13.2 2.6 7 2.4 22.1 51.7 39 20 5.1 12.2 5 6.5 3 22.2 53.9

In the Riverside-Basin San Bernardino C ounties grouping 5 of the 7 grid cells have annual average concentr ations within 2.5 μg/m 3 of the federal standard. Two grid cells (36,16) and (36,20) ha ve predicted annual averag e concentrations above 63 μg/m 3 . Primary paved road dust and dust from construction and demolition activities account for th e bulk of the primary PM10 emis sions to the five grid cells that had predicted annual averag e concentrations with 2.4 μg/m 3 of the standard. From the sensitivity analysis previously discussed, pa ved road dust typically contributes between 6 to 8 μg/m 3 to annual average concen tration at the Riverside and San Bernardino sites, respectively. Over-estimation of the paved road dust PM10 emissions by 3 μg/m 3 is consistent with the estimation for the west Basin and that adjustment alone would bring the fi ve sites within the federal standard. Uncertainties in the surrogates used to allocate construction and demolition dust associated and the expected construction gr owth also contribute to potentially lower annual average concentrations at those grid cells.Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 54

Table 2-20
PM10 Emissions Source Categories fo r 2006 Hot Spot Grid Cells

Source Category Source Description

46987 Mineral Processes Other (Miscellaneous) Processes
47274 Waste Burning and Disposal -- Forest Management
47340 Farming Operations -- Cattle Feed Lots
47357 Construction and Demolition -- Buil ding Construction Dust Residential
47365 Construction and Demolition -- Buil ding Construction Du st Commercial
47373 Construction and Demolition -- Bu ilding Construction Dust Industrial
47381 Construction and Demolition -- Road Construction Dust
47399 Road Dust - Unpaved Road Travel Dust - City and County Roads
54551 Construction and Demolition -- Buil ding Construction Dust Institutional
60418 Other-Commercial Charbroiling
82123 Residential Fuel Combusti on-Wood Combustion-Fireplaces
83337 Fugitive Wind Blown Dust -Agricultural Lands
83352 Fugitive Wind Blown Dust - Unpaved Roads
83618 Road Dust - Paved Entrained Road Dust - Freeways
83626 Road Dust - Paved Entrained Road Dust - Major Roads
83634 Road Dust - Paved Entrained Road Dust - Collector Streets
83642 Road Dust - Paved Entrained Road Dust - Local Streets
84863 Fugitive Wind Blown Dust - Pasture Lands
89078 Off-Road Diesel EquipmentChapter 2 PM 10 Attainment and Visibility

V - 2- 55 Table 2-21
2006 Hot Spot Grid Cells Vent ura, L.A. and Orange County: PM10 Emissions (KG/Day) By Source Category

Grid (xx,yy) Source Category 1824 2315 2915 2916 3015 2132

83618 135 265 322 401 339 0 47274 0 0 0 0 0 1965 83626 281 180 242 158 144 0 83642 160 104 136 157 197 0 47365 45 28 204 135 135 0 89078 48 4 23 51 31 0 60418 42 28 47 56 49 0 47357 28 21 38 36 39 0 54551 24 15 32 22 21 0

Table 2-22
2006 Hot Spot Grid Cells Rivers ide and San Bernardino County: PM10 Emissions (KG/Day) By Source Category

Grid (xx,yy) Source Category 3520 3616 3619 3620 3621 3717 3920

83642 138 83 112 103 30 117 150 83626 251 60 126 69 134 120 148 83618 0 143 79 127 102 100 123 83352 436 6 5 3 4 15 4 47365 70 0 26 46 160 16 0 47373 120 0 15 117 53 0 24 47357 18 0 72 64 50 48 0 60418 7 15 17 0 0 77 35 83634 11 16 23 25 13 34 11 54551 9 15 0 8 5 59 5 47340 0 0 73 0 3 0 0

Grid cell (36,16) is particularly impacted by fugitive dust emi ssions from unpaved roads together with large contributions from paved road dust and construction and demolition dust as well. Ap proximately 5.5 percent of all Basin fugitive dust emissions from unpaved roads (8.7 TPD) are located in that one grid cell. Interestingly, the bulk of grid cell (36, 16) resides in the C ity of Corona in aFinal 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 56 developed portion of the city that includes a shopping pl aza and a maintained golf course. As a consequence, the amount of particulate emissions from unpaved roads may have been misallocated to that grid. Without the fugitive unpaved road dust emissions, the total listed in Table 2-22 for grid cell (36,16) are comparable with those of the other five grid cells (exc ept 36,20). In addition, while future construction growth is reasonable, uncerta inties exist in the estimated amount of 2006 construction, given the level of current development of the area. With adjustments for paved fugitiv e unpaved road dust, paved road dust and construction emissions it is likely that grid cell (36,16) would meet the 50.4 μg/m 3 threshold.
Grid cell (36,20) has a significant contribu tion from paved road dust and construction dust to its major particulate emissions and th e predicted primary impact to that grid should be weighted by the uncertainties in those emissions estimates. Grid cell (36,20) is also directly downwind of th e cell 35,19 which has one of the highest concentrations of cattle feed lot emissions (0.77 TPD) in the Basin. The cattle feed lot emissions were used as a surrogate for dairy farm dust emissions. There is huge amount of uncertainty in these emissions si nce dairy farms are typically well irrigated and do not raise the same amount of dust as cattle feed lots. In addition, the area of grid cell (35,19) is rapidly being transformed from dairy farms to warehouse distribution centers. It is unlikely that in 2006, many of the dairy farms will continue to be in operation.
The results of the "hot-spot" grid cell analysis indicate that the UAMAERO-LT simulation for 2006 meets the federal standa rd when localized an omalies in primary emissions specification and systematic ove r-estimation of the paved road dust estimates are identified and accounted.

Maximum 24-Hr Average PM10
The maximum 24-hour average PM 10 concentrations in the ye ar 2006 for each site with and without emission cont rols are shown in Table 2- 23 Los Angeles will meet the federal 24-hour average PM 10 standard without emission controls in 2006. With emission controls, the entire Basin will attain the federal 24-hour average PM 10 standard of 150 μg/m 3 in 2006.

None of the sites in the Basin will me et the state maximum 24-hour average PM 10 standard of 50 μg/m 3 in the year 2006, even with the proposed emission controls.Chapter 2 PM 10 Attainment and Visibility

V - 2- 57

Table 2-23
Maximum 24-hr Average PM 10 Concentrations (μg/m 3 ) in the Year 2006

Anaheim Diamond Bar Fontana Los Angeles Rubidoux Without Control With Control Without Control With Control Without Control With Control Without Control With Control Without Control With Control

Total PM 10 138.5 137.5 124.4 123.3 129. 2 128.4 117.8 116.7 155.6 150* * With EPA Rounding Convention [40 CFR Part 50, Appendix K]



### PM 10 

### in the Year 2010

Annual PM10
The annual average PM 10 concentrations in th e year 2010 for each PM 10 species with and without emission controls are shown in Table 2-24. With an d without controls, the all sites will meet the federal annual average PM 10 standard. However, even with controls in place, none of the sites will meet the state annual average PM 10 standard in 2010, regardless of the control option selected.

TABLE 2-24 Annual Average PM 10 Concentrations (μg/m 3 ) in the Year 2010

Anaheim Diamond Bar Fontana Los Angeles Rubidoux
Control Control Control Control Control Component

Base
Opt-1 Opt-2 Base
Opt-1 Opt-2 Base
Opt-1 Opt-2 Base
Opt-1 Opt-2 Base
Opt-1 Opt-2
Ammonium 3.8 3.2 3.3 3.5 3.0 3.1 4.4 3. 7 3.8 2.8 2.4 2.5 4.3 3.5 3.5

Nitrate 10.3 7.7 8.4 10.1 7.8 8.2 11.3 8. 9 9.0 7.4 5.9 6.2 11.6 9.1 9.2

Sulfate 3.2 3.2 3.2 2.7 2.7 2.7 3.9 3. 9 3.8 2.6 2.4 2.4 3.3 3.0 2.9

Organic Carbon 6.7 6.0 6.2 5.4 4.8 5.0 5.8 5. 6 5.5 5.4 4.9 5.0 6.6 6.3 6.4

Elemental Carbon 2.6 2.5 2.5 2..1 2.0 2.0 2.8 2. 7 2.7 2.0 1.9 1.9 2.7 2.4 2.5

Primary 23.0 22.8 22.8 16.0 15.9 15.9 20.3 20. 2 20.2 17.7 17.5 17.5 21.5 20.7 20.7

Total PM 10 49.7 45.4 46.4 39.8 36.3 36.8 48.4 44. 7 45.0 37.8 35.3 35.7 50.1 45.0 45.2Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 58 Maximum 24-Hr Average PM10
The maximum 24-hour average PM 10 concentrations in the ye ar 2010 for each site with and without emission controls are show n in Table 2-25. A ll sites will meet the federal 24-hour average PM 10 standard with and without emission controls in 2010. None of the sites in the Basin will me et the state maximum 24-hour average PM 10 standard in the year 20 10, even with the proposed emission controls.

TABLE 2-25 Maximum 24-Hour Average PM 10 Concentrations (μg/m 3 ) in the Year 2010

Anaheim Diamond Bar Fontana Los Angeles Rubidoux
Control Control Control Control Control Component

Base
Opt-1 Opt-2 Base
Opt-1 Opt-2 Base
Opt-1 Opt-2 Base
Opt-1 Opt-2 Base
Opt-1 Opt-2

Total PM 10 129.1 110.8 115.8 113.5 93.8 99.4 124.9 113.2 116.2 107.2 88.4 93.7 148.7 132.9 137.1



### PM 2.5 

### in the Year 2010

Annual PM 2.5 The annual average PM 2.5 concentrations in th e year 2010 for each PM 2.5 species with and without emission controls (both options ) are shown in Table 2-26. The future year PM 2.5 is presented to provide an assessm ent as to the amount of additional emissions reductions that will be required to meet the federal PM 2.5 standard when the propose 2014 attainment date is implem ented. With and w ithout controls, the predicted PM 2.5 concentrations for Basin in 2010 will exceed the federal PM 2.5 standard. For the five ke y sites, annual average PM 2.5 concentrations are predicted to exceed the federal standard by a minimum of 31 percent at Central L.A. to a high 89 percent at Fontana.Chapter 2 PM 10 Attainment and Visibility

V - 2- 59

Table 2-26
Annual Average PM 2.5 Concentrations (μg/m 3 ) in the Year 2010

Anaheim Diamond Bar Fontana Los Angeles Rubidoux
Control Control Control Control Control Component

Base
Opt-1 Opt-2 Base
Opt-1 Opt-2 Base
Opt-1 Opt-2 Base
Opt-1 Opt-2 Base
Opt-1 Opt-2

Ammonium 3.4 2.9 3.0 3. 2 2.7 2.8 4.0 3.4 3.4 2. 5 2.2 2.3 3.9 3.2 3.2

Nitrate 7.6 5.7 6.2 7.5 5.8 6.1 8. 4 6.6 6.7 5.5 4.4 4.6 8.6 6.7 6.8

Sulfate 2.6 2.6 2.6 2.2 2.2 2.2 3. 2 3.2 3.1 2.1 2.0 2.0 2.7 2.5 2.4

Organic Carbon 4.8 4.1 4.3 4.0 3.5 3.6 4.3 4. 1 4.0 3.8 3.4 3.5 5.1 4.8 4.9

Elemental Carbon 2.3 2.2 2.2 1.9 1.8 1.8 2.5 2. 4 2.4 1.8 1.7 1.7 2.3 2.1 2.2

Primary 6.8 6.7 6.7 5.3 5.2 5.2 7. 6 7.5 7.5 5.4 5.3 5.3 7.5 7.0 7.0

Total PM 2.5 27.7 24.3 25.1 24.1 21.3 21.7 29.9 27. 0 27.2 21.1 19.1 19.4 30.2 26.3 26.4

Maximum 24-Hr Average PM 2.5 The maximum 24-hour average PM 2.5 concentrations in the year 2010 for each site with and without emission controls are shown in Table 2-27. None of the sites will meet the federal 24-hour average PM 2.5 standard (65 μg/m 3 ) without emission controls in 2010. With emission controls, the fe deral 24-hour average PM 2.5 standard is predicted to be attained at Anaheim, Los Angeles and Rubidoux (both control options) and at Diamond Bar fo r control option-1. The PM 2.5 standard is not attained at Fontana, regardless of control option selected.

TABLE 2-27 Maximum 24-Hour Average PM 2.5 Concentrations (μg/m 3 ) in the Year 2010

Anaheim Diamond Bar Fontana Los Angeles Rubidoux
Control Control Control Control Control Component

Base
Opt-1 Opt-2 Base
Opt-1 Opt-2 Base
Opt-1 Opt-2 Base
Opt-1 Opt-2 Base
Opt-1 Opt-2

Total PM 10 76.5 59.1 63.9 84.9 65.0 70.6 79.3 68.4 71.3 67.8 52.2 56.5 76.8 64.4 67.7Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 60 

### PM 10 

### in the Year 2010 With Al ternative Control Options
As part of the California Environmental Qua lity Act (CEQA) requirements, four alternatives to the two propo sed control plan options fo r 2010 were evaluated for both the ozone and PM 10 attainment plans. These options include:

• Alt.-1: No Project Taking Place.

• Alt.-2b: Lower VOC (~ 250 TPD) with Control Option-2.

• Alt.-3: Lower VOC (~250 TPD) with Control Option-1.

• Alt.-4 Least amount of Toxic Emissions Option. .

Annual and 24-hour maximum c oncentration PM10 simulati ons for total mass were conducted for the alternativ e emissions scenarios. Th e results of the annual simulations are presented in Table 2-28 . The results of the 24-hour maximum concentration simulations are presented in Table 2-29.
All of the alternative controls strategies will result in the both th e annual and 24-hour maximum federal PM 10 standards to be attained in 2010 at all sites.

Table 2-28

Alternative Emissions Control Scenar ios: Predicted Annual Average PM 10 Concentrations (μg/m 3 ) in the Year 2010

Scenario Anaheim Diamond Bar Fontana Los Angeles Rubidoux

Alt.-1 47 38 45 36 47

Alt.-2b 46 36 45 36 45

Alt.-3 45 36 44 35 44

Alt.-4 45 36 45 35 45Chapter 2 PM 10 Attainment and Visibility

V - 2- 61 TABLE 2-29
Alternative Emissions Control Scenarios: Predicted 24-Hour Average Maximum PM 10 Concentrations (μg/m 3 ) in the Year 2010

Scenario Anaheim Diamond Bar Fontana Los Angeles Rubidoux

Alt.-1 123 106 120 101 142

Alt.-2b 115 99 116 93 136

Alt.-3 110 93 113 88 132

Alt.-4 109 91 112 86 131



### CONCLUSIONS
In the year 2006 , and continuing through 2010, PM 10 concentrations will be reduced to levels such that the entire Ba sin will comply with both federal PM 10 standards, annual average and maximum 24-hour average (s ummarized in Figures 2-25 and 2- 26, respectively) with the proposed emissi on controls. However, neither of the state PM 10 standards can be met by 2006 or 2010 with the proposed emission controls. Further emission controls will be necessary to meet the state PM 10 standards.
As part of the federal Clean Air Act requirements for the PM 10 attainment demonstration, interim milestone emissi on reduction targets must be provided for every three years to th e attainment year.Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 62 0 10 20 30 40 50 60 70 80

Central LA Anaheim Diamond Bar Fontana RubidouxConcentration (ug/m3)

1995-Baseline 2006-Baseline 2006-Controlled 2010-Baseline 2010-Control O p t.-1 2010-Control O p t.-2

FIGURE 2-25 Future Projected Annual Average PM 10 for the Baseline and Control Emissions Scenarios

0 50 100 150 200 250

Central LA Anaheim Diamond Bar Fontana RubidouxConcentration (ug/m3)

1995-Baseline 2006-Controlled 2010-Control Opt.-1

FIGURE 2-26 Future Projected Maximum 24-Hour Average PM 10 for the Baseline and Control Emissions ScenariosChapter 2 PM 10 Attainment and Visibility

V - 2- 63 

### VISIBILITY
Background
Visibility impairment plays an important role in the public ’s perception of the general state of air quality, since it is one of the most obvious indicators of air pollution. In 1969, California promulgated an ambient air quality sta ndard for “visibility-reducing particles,” limiting the concentration of thes e particles to an amount which would not reduce the visibility below 10 miles when the relative humidi ty was less than 70 percent. On January 13, 1989, the California Air Resources Board (ARB) established a new visibility standard ba sed on instrumental determination of atmospheric extinction coeffi cient. Effective in Octo ber 1989, the new standard states that the concentration of “visibility -reducing particles” vi olates the standard when it produces an extinction coefficient gr eater than 0.23 per kilometer (equivalent to visibility less than 10 miles) with relative humidity less than 70 per cent, averaged over the period from 10:00 am to 6:00 pm, Pacific Standard Time (ARB, 1989). There is no requirement to comply with the state visib ility standard by a specified date; however, future-year visibility is estim ated to illustrate th e progress toward the attainment of the state standard.


### Visibility Modeling

To establish the most reasonable control strate gy to meet the visibility standard in the future, a relationship between visibility a nd concentrations of visibility reducing particles must be established. This, in turn, requires visibility modeling techniques to identify sources of visibility reducing par ticles and to quantify their impacts.
The total atmospheric light extinction can be broken down into four basic components: scattering of light by partic les, absorption of light by particles, absorption of light by gases, a nd scattering of light by gase s (Rayleigh scattering). In general, total light extinction is dominated by scattering of light due to particles, with light absorption by particles being second in importance. The components other than scattering of light by par ticles have been well-charac terized by theory or from previous studies. Therefore, light extinct ion by particle sca ttering is normally estimated either by visi bility modeling or by direct measurement.
Multiple linear regression is a statistical tool commonly used for characterizing the relationship between visibility and ambien t air quality of the visibility reducing particles. When atmospheric light extinction due to particle scattering is regressed on concentrations of visibility reducing particles, the regre ssion coefficients represent the extinction efficiency due to particle scattering (ex tinction per unit concentration) for each air pollutant species.Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 64 Multiple linear regression was employed in the 1991 AQMP to develop empirical predictive equations. Empirical visibility model developed in the 1991 AQMP for Riverside were utilized in the current AQMP analysis to estimate future visibilities with new future-year (2006, and 2010) organic carbon concentrations, sulfate, and nitrate concentrations which were obtaine d from the UAMAERO-LT model. Details of the statistical analysis used to develo p the empirical predic tive equations can be found in Technical Report V- G of the 1991 AQMP.


### Prior Visibility Modeling Results
In the 1991 AQMP, the regression analysis resulted in several sets of extinction efficiencies for light scattering by particles for Riverside (Rubido ux station) and four additional measurement loca tions. Combining extinction efficiencies for light scattering by particles with the empirical expressions for the ot her light extinction component produces a series of empirical predictive equations. Empirical predictive equations relate light extinction to concentr ations of visibility reducing air pollutants and have the following form:

b ext = Summation ( b i 

### . C i )+ b RAY
where b i = extinction efficien cy for ith species (10 -4 m -1 /μg/m 3 or 10 -4 m -1 /pphm)

C i = mean concentration for ith species (μg/m 3 or pphm)

b RAY = extinction due to Rayleigh scattering in the Basin (10 -4

m -1 )
Table 2-30 is a summary of the 1991 AQMP results, showing the extinction efficiency, b i , for Riverside. (The extinction efficiency, b i , for the other locations analyzed in the 1994 AQMP can be found in 1994 AQMP, Technical Report V-C).
A baseline light extinction budget was de termined for each empirical predictive equation using the mean meas ured values of the air quality components for the baseline year 1986. The light extinction budget for Riverside during the baseline emission year is summarized in Table 2-31. These show the percent contribution to total extinction from each com ponent for each equation.
At Riverside light scattering by particles a ccounts for up to 87 percent of the total light extinction with secondary nitrate and carbon particles being dominant.Chapter 2 PM 10 Attainment and Visibility

V - 2- 65 TABLE 2-30 Riverside Extinction Efficiencies, b i , Defining Alternate Sets of Empirical Predictive Equations for Light Extinction

Visibility-Reducing Alternate Equations 1 Species Units 1 2 3 4

Riverside SULF (10 -4 m -1 /μg/m 3 ) b 1 NITR (10 -4 m -1 /μg/m 3 ) b 2 0.070 0.075 IONS (10 -4 m -1 /μg/m 3 ) b 3 0.055 0.058 OC (10 -4 m -1 /μg/m 3 ) b 4 0.104 0.089 CRBN (10 -4 m -1 /μg/m 3 ) b 5 0.062 0.053 EC (10 -4 m -1 /μg/m 3 ) b 6 0.119 0.119 0.119 0.119 NO 2 (10 -4 m -1 /pphm) b 7 0.033 0.033 0.033 0.033 molecules (10 -4 m -1 ) b RAY 0.114 0.114 0.114 0.114

TABLE 2-31 Current Light Extinction Budgets for Each Alternate Empirical Predictive Equation at Each Measurement Location 2 (in percent of total light extinction)

Alt ______________ b sp ______________ Location Eq. SULF NITR IONS OC CRBN b ap b ag b RAY

Riverside 1 58 29 8 2 3 2 66 21 8 2 3 3 62 25 8 2 3 4 62 25 8 2 3

1 Alternate equations in the set of empirical predic tive equations defined for each measurement location.
2 Based on mean annual average concentr ations derived fro m 1986 measurements.Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 66 

### Predicted Future Air Quality
Future air quality levels are needed to estimate future visual air quality. The concentrations of the inorga nic particulate matter species (sulfate and nitrate) for future years 2006, and 2010 are taken from the results of the UAMAERO-LT modeling analysis.
Future concentrations of pa rticulate organic carbon, particulate elemental carbon, and gaseous NO 2 are estimated from the mean annual concentrations measured during 1986 using linear rollback. Linear rollback assumes that the change in pollutant levels at any location in the Basin is linea rly proportional to the expected change in basin-wide emission loading.

Future NO 2 concentrations are estimated from NO x emissions, particulate organic carbon from emissions of VOCs and partic ulate elemental carbon from diesel particulate emissions. Natural background concentrations for each of these are assumed to be negligible for this analysis.
Table 2-32 gives the basin-wide emission totals for VOC, NO x , SO x and diesel particulate matter. Totals are given for 1990 (the baseline emission year) and for future years 2006, and 2010 with two em ission control scenarios: baseline (no additional controls) and controlled.

TABLE 2-32
Baseline and Future Controlle d Emissions (tons per day)

Pollutant 1990 2006 b 2010 b 2006 c 2010 c
VOC 1780 689 615 674 295 NO x 1592 943 771 935 543
SO x 98 60 60 57 59
Diesel Particulate 33 20 18 20 12
b without AQMP control strategies

c with AQMP control strategies

Estimated future baseline and controlled levels for all pollu tant species that affect visibility are shown in Tables 2-33.Chapter 2 PM 10 Attainment and Visibility

V - 2- 67 TABLE 2-33 Riverside Air Quality Levels for the Years 2006 and 2010 Future Baseline and Controlled (2010 Opt.-1)

Component Units Baseline Controlled

2006
SULF 1 μg/m 3 5.0 4.5

NITR 1 μg/m 3 19.6 19.3 IONS μg/m 3 24.6 23.8
OC 2 μg/m 3 5.5 5.5

EC 2 μg/m 3 2.7 2.5 CRBN μg/m 3 9.3 9.1
NO 2 2 pphm 1.5 1.5

2010
SULF 1 μg/m 3 5.3 4.9

NITR 1 μg/m 3 18.8 14.7 IONS μg/m 3 24.1 19.6
OC 2 μg/m 3 5.5 5.3

EC 2 μg/m 3 2.7 2.4 CRBN μg/m 3 9.3 8.7 NO 2 2 pphm 1.3 0.9



### Future Visibility Projections
Riverside Future Mean Visibility
Tables 2-34 and 2-35 compare the predicted future visibility with the current levels based on measurements. The results for the baseline emission scenario (no further emission controls) are shown in Table 2- 34 and the results for the controlled emission scenarios are shown in Table 2-35. Each table shows the predicted annual average light extinction coeffi cients compared to the tota l light extinction coefficient derived from 1986 measurements and the mean visual range estimated from the measured and predicted extinction coe fficients. Figure 2-27 illustrates the improvement in visibility in terms of th e annual visual rang e for both emission control scenarios.Final 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 68 TABLE 2-34 Projected Future Visibility, Base line without Future Controls

Year Alt. Eq. 1 Total Light Extinction Coefficient (10 -4 m -1 ) Calculated Visual Range (miles)
Baseline 3.9 4.8
2006 1 2.328 8.0 2 2.429 7.7 3 2.406 7.7 4 2.531 7.4
2010 1 2.292 8.1 2 2.363 7.9 3 2.368 7.9 4 2.461 7.6

TABLE 2-35 Projected Future Visibility, With Controls

Year Alt. Eq. 1 Total Light Extinction Coefficient (10 -4 m -1 ) Calculated Visual Range (miles)

Baseline 3.9 4.8
2006 1 2.260 8.2 2 2.382 7.8 3 2.324 8.0 4 2.470 7.5
2010 1 1.973 9.4 2 2.006 9.3 3 2.026 9.2 4 2.073 9.0

1 Alternate equations in the set of predictive em pirical equations defined for each measurement location.Chapter 2 PM 10 Attainment and Visibility

V - 2- 69 FIGURE 2-27 Annual Average Daytime Visibility Projections, Miles

For the baseline emission contro l scenario, there is a decrea se in the total extinction coefficient from the ba seline to the year 2010. The visual range will subsequently increase by about 3.0 miles by 2006 to 7.7 m iles and increase an additional 0.2 miles to 7.9 miles in 2010.

For the controlled emission scen ario, the total extin ction coefficient is reduced to less than half of the base year value. Corresponding visual range improves from 4.8 miles in the base year to 9.3 miles in 2010. The predicted future visibilities are consistent with the observed annual aver age visual range in areas influenced by marine air (with the attendant marine haze). Without significant air pollution sources, median mid-day visibilities along the California coast are generally less than 25 miles (Trijonis, 1980).
Future Light Extinction Budgets at Riverside
Table 2-36 compares the baseline and futu re projected light extinction budgets determined from one of the alternate em pirical equations for each location to illustrate changes in the importance of ea ch pollutant component to overall light extinction. These changes re sult from alterations in the future pollutant mix and in the spatial distribution of sources. 

### 0 2 4 6 8 10

1986 2006 2010Visibility (Miles)



### Baseline Control

0 2 4 6 8 10

1986 2006 2010Visibility (Miles)



### Baseline ControlFinal 2003 AQMP Appendix V: Mode ling and Attainment Demonstrations

V - 2- 70

Table 2-36
Comparison of Baseline and Futu re Projected Light Extinction Budgets for Riverside (% contribution)

Baseline Controlled Component 1986 2006 2010 2006 2010
NITR 60 56 56 57 51 OC 29 24 24 24 27 EC 8 13 14 12 14 NO 2 2 2 2 2 1 RAY. 3 5 5 5 6
The light extinction budget for Riverside changes very little for the fu ture baseline emission cases except for the fo llowing: (1) nitrate remain s the major contributor but its contribution decreases; and (2) elem ental carbon contributions increase by approximately one third from the base year then remain constant through 2010.
The projected light extinc tion budgets for the years 2006 and 2010 with the controlled emission scenarios are relatively equivalent to the baseline budgets but show changes from the 1986 ba seline, most notably from the smaller contribution by nitrate and a nominal increase due to elemental carbon.



### CONCLUSIONS
In general, visibility is a tangible indicato r of air quality. Particulate matter in the atmosphere causes not only visibility reducti on but also adverse health effects. Visibility in the Basin has shown improveme nt over the last 30 years; however, the California state visibility sta ndard continues to be violated throughout the Basin. Visibility impairment in the Basin is primar ily due to the scatte ring and absorption of light by fine particles suspended in the atmosphere.
Without emission controls, visibility is pred icted to improve only marginally. With the proposed emission controls, annual av erage visibility will im prove from a range of approximately 5.0 miles at Riverside to 7.7 miles by 2006 and to 7.9 miles by 2010. This level of improvement is consis tent with visibilities experienced in the non-urban coastal areas of California that have little impact from man-made sources but are affected by marine haze.
Total extinction coefficient improves by a pproximately 50 percent by the year 2010 with the implementation of controls. Th is corresponds to an improvement in the annual average visual range from less than 5 to more th an 9 miles at Riverside by 2010.

## CHAPTER 3 REVISION TO THE 1997 OZONE ATTAINMENT DEMONSTRATION PLAN

Introduction Emissions Summary Episode Selection Modeling Methodology
Model Validation Future Ozone Air Quality Projections Sensitivity Studies Summary and ConclusionsChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 1 

### INTRODUCTION
The 2003 AQMP Ozone Attainment Demonstra tion Plan to meet the federal 1-hour average standard (124 ppb) is presented in this chapter. The modeling Attainment Demonstration serves as a revision to th e 1997 ozone Attainment Demonstration Plan (Ozone Plan) submitted to EPA as part of the California State Implementation Plan (SIP). The ozone modeling attainment dem onstration relies on an established modeling system the Urban Airshed Model (UAM) w ith the Carbon Bond IV (CB-IV) mechanism (Morris and Myers, 1990) and two modeling episodes. Th e primary modeling episode used in the current analysis, August 5- 6, 1997, occurred during the 1997 Southern California Ozone Study. This episode is one of several meteorological episodes that were intensively monitored through the field program. A se cond meteorological episode, August 27-28, 1987, that was pr eviously used in the 1994 and 1997 AQMP ozone attainment demonstrati ons was included in the analys is to provide continuity between Ozone Plans. The base year for the ozone modeling demonstration and emissions inventory ch aracterization is 1997.
Note, only August 5 th and 6 th of the 1997 meteorological episode are used in the ozone attainment demonstration. As discussed in Chapter 1, August 4, 1997 was considered a "ramp-up" day for the ozone simulation and as such was excluded from the attainment demonstration analysis. However, the mete orological fields generated for August 4, 1997 are included in the discu ssion of meteorological input preparation in a following section of this chapter. The meteorologica l fields are included in the discussion to support the overall evaluation of how well the modeled meteorological fields recreate the meteorological conceptual model defining the episode.
This chapter provides the background for th e development of the components that contribute to the ozone modeli ng attainment demonstration. Included are discussions of the modeling tool selected for the demonstra tion, federal and state air quality standard requirements, and base and future year emi ssions. The selection and characterization of meteorological episodes and prep aration of the ozone simula tion model input is provided in detail. The analysis also provides th e base year model va lidation and supporting statistical and graphical documentation.
Ozone air quality is projected using the UAM for the following futu re years: 2007 and 2010. The year 2007 is used in the discussi on of federal attainme nt demonstration for the severe-17 Coachella Valley nonattainment area. The year 2010 was chosen for UAM modeling to demonstrate attainment of the fe deral ozone standard in the South Coast Air Basin. Additional analyses provide charact erization of future year air quality for alternative emissions control strategies.Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 2 

### Model Selection
Projections of future air quality rely on th e use of computer simulation models. The model used in the 2003 AQMP to project futu re ozone air quality and to determine the effectiveness of the proposed control strategi es is the Urban Airs hed Model (UAM) with the Carbon Bond IV (CB-IV) mechanism (Morri s and Myers, 1990). The analysis uses UAM version 6.23 for the attainment demons tration. U.S. Envi ronmental Protection Agency's (EPA) modeling guidelines reco mmends the use the UAM model for urban scale modeling simulations.
As previously discussed in Chapter 1, EPA's guidance also promotes the use of state-ofthe-art modeling systems provided that they pe rform equal to or better than the reference model (UAM). As such, several additional ca ndidate models were evaluated for use in the 2003 AQMP. The California Photochemi cal Grid Model (CALGRID) with the CBIV and SAPRC99 chemical mechanisms as well as the Compre hensive Air Quality Model with Extensions (CAMx) also w ith CB-IV and SAPRC99 chemistry were extensively evaluated for inclusion in the oz one modeling attainment demonstration. The performance of CALGRID and CAMx to recreate the patterns of ozone in space and time exceeded those of UAM. Both CALG RID and CAMx met EPA's baseline model performance criteria for the critical geographica l receptor area of the Basin, however, each model under predicted obser ved unpaired peak concentra tions. In contrast the UAM predicted peak concentration essen tially matched the unpaired observed peak concentration.
While no stated preference is made as to relative importance of the individual performance criteria used to evaluate the different models, the ability to recreate observed peak concentrations ra nks high. The peak concentr ation represents the starting threshold from which emissions need to be reduced to meet the standard. Under prediction of the peak concentrations can lead to significant uncertainty in Basin carrying capacity estimation. Both CA LGRID and CAMx, (each model using CB-IV and SAPRC99 chemistry), under predicted the base-year peak concentrations by more than 10 percent. This trend of under prediction of observed ozone was also demonstrated by the CAMx and CALG RID performance on a 2002 "mid-course" simulation analysis. Uncertainties in the application of the SA PRC99 chemistry and speciation of VOC from biogenic sources ne eded for the SAPRC99 chemistry further complicated the evaluation of the CALGRID and CAMx simulations.
For the 2003 AQMP, UAM has been selected as the primary modeling tool for the ozone attainment demonstration. The decision to use UAM rests on the model's ability to recreate the observed peak concentration, coupled with its performance on the "mid course" simulation and the District's extens ive experience with UAM in prior AQMPs. The District is committed to moving towards the use of the state-of-the-science air quality simulation models. At this time, CALGRID/SAPRC99 model simulations showChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 3 consistency with the UAM future year simulations. Unfortunately, the CAMx simulations do not show as much promise. If the issues with that have discussed here and in Chapter 1 are resolved prior to adop tion of the final plan, a technical document addressing the CALGRID/SAPRC99 base and fu ture year simulations will be appended to this document as suppor ting weight of evidence to the ozone attainment demonstration.



### Federal 1-Hour Ozone Standard Requirements
Air quality modeling is required by both th e federal Clean Air Act (CAA) and the California Clean Air Act (CCAA). Section 182(b)(1)(A) of CAA requires that moderate and above ozone nonattainment areas must reduce volatile orga nic compounds (VOC) and oxides of nitrogen (NO x ) emissions sufficiently to a ttain the national ambient air quality standard for ozone and an attainment demonstration must be performed using photochemical grid modeling. According to Section 181(a)(1) of the CAA, ozone nonattainment areas are classified and give n an attainment deadline based on their design values. Within the jurisdiction of the District are the South Coast Air Basin (Basin) and the Coachella Valley of the Sa lton Sea Air Basin (see Figure 3-1). The Basin is classified as an extreme ozone nonattainment area and therefore has an attainment deadline of November 15, 2010. The attainment demonstration for the Basin is the primary subject of this chapter. The Co achella valley is classified as a “severe-17” ozone nonattainment areas and th erefore have an attainment deadline of November 15, 2005 with a two year extension to 2007.
The modeling domain used in the photochemi cal modeling analysis, also shown in Figure 3-1, encompasses the entire Basi n, Ventura County, Antelope Valley (AVAQMD), San Diego County, the Coachella Valley, and portions of the Mojave Desert Air Quality Management District (MDAQMD) and Imperial County. Ventura county, classified as a se vere ozone nonattainment area (attainment year: 2005), the Antelope Valley and Mojave De sert are classified as "severe-17" (attainment year: 2007), experience pollutant trans port from the Basin, and at tim es is an upwind source of pollution.



### California Requirements and Population Exposure
The CCAA requires the District to demons trate reasonable progress towards achieving state ambient air quality standards in the Ba sin. The CCAA require s per-capita exposure reductions for the years 1994, 1997, and 2000, as compared to a 1986-88 base period. Overall per-capita exposure to ambient ozone must be reduced in accordance with the following schedule: 25 per cent by 1994, 40 percent by 1997, and 50 percent by 2000.Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 4 To date, the Basin has not met the Califor nia 1-hour ozone sta ndard (90 ppb) yet, ambient ozone air quality has greatly improved.
For the 2003 AQMP, the Regional Human E xposure model (REHEX) is used to determine per-capita exposure reductions based on observed ozone air quality. In previous plans, REHEX was coupled with the output of the UAM regional photochemical simulations to estimate future year population expos ure to address the CCAA requirements. While the current ozone modeling attainment demonstration uses 1997 as a base year for the attainment de monstration, observati onal ozone data are available for the milestone years identified by the CCAA. The results of the REHEX per-capita population exposure an alysis for the milestone y ears using the observed ozone air quality are presented in Table 3-1. In summary, the population exposure requirement defined by the CCAA has been achieved.

Figure 3-1
Southern California Modeling Domain Used in the Ozone Attainment DemonstrationChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 5 Table 3-1
CAAA Population Exposure Assessment
Period Per-Capita Ozone Exposure (pphm-hr) Percent Improvement from 1986-1988 1986-1988 132.57 N/A 1994 50.16 62 % 1997 7.98 94 % 2000 4.61 97 %



### EMISSIONS SUMMARY

Introduction
There are specific emission inventories deve loped for the photochemical modeling. The summer planning emission inventories devel oped for the histori cal years (1987, and 1997) and future planning years (baseline and controlled) are descri bed in Appendix III. Baseline modeling inventories for the histor ical years (1987 and 1997) and the future years (2007, 2010, and 2020) are discussed next. Two emission projections are needed for each of the modeled future years. The first is the projecte d emissions assuming no further emission controls. These projecti ons are commonly referred to as “baseline emissions” (e.g., 2010 baseline emissions), a nd reflect the emissions resulting from increases in population and vehicle miles trav eled (VMT), as well as the implementation of all adopted rules and re gulations up to November 30, 2002. The second emission projections reflect the implementation of the 2003 AQMP control measures on the future baseline emissions. For a detailed descrip tion of the 2003 AQMP control measures, the reader is referred to the main volume and Appendix IV.
The 1987 and 1997 historical year emissions are summarized first for the two ozone episodes used for attainment demonstration. This is followed by a discussion of the future-year baseline emission inventories. Fi nally the future-year emission inventories, assuming implementation of pr oposed control measures, ar e presented. Appendix III contains emission summary reports by source category for the hi storical base year, future baseline, and future controlled scenarios used in this modeli ng analysis. Attachments 4, 5, and 6 of this appendix c ontain an emissions summary report by source category for the future (2006 and 2010) controlled scenar ios for the annual average inventory, and the 2010 controlled scenario for the planning inventory, respec tively. It should be noted that the inventories reported here may be s lightly different than those reported in the 2003 AQMP and Appendix III, since the invent ories used for modeling reflect dayspecific conditions.Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 6 

### Historical Baseline Emissions
Historical baseline emissions of oxides of nitrogen (NO x ) and volatile organic gases (VOC) and carbon monoxide (CO) are su mmarized in Table 3-2 for the two meteorological episodes used for modeling. The summaries of on-ro ad mobile, off-road mobile, and stationary source emissions ar e reported for the Basin and the modeling region. Emissions for each of the 1987 episode s are significantly higher than for 1997.

TABLE 3-2 Historical Episode Emissions (tons/day)*

Episode South Coast Air Basin Modeling Region** Source Type VOC NO x CO VOC NO x CO August 1987 On-Road 1429 1241 14008 1587 1390 15821 Off-Road 162 385 1068 191 470 1240 Stationary 817 215 91 927 308 143 Total 2408 1841 15167 2705 2168 17204

August 1997 On-Road 580 822 5634 887 1244 8691 Off-Road 218 341 1246 301 521 677 Stationary 464 120 56 759 351 300 Total 1262 1283 6936 947 2116 10668

* Emissions are for the peak ozone day of each episode. ** Excludes emissions from Mexico.

Table 3-3 provides the modeli ng region wide biogenic emissi ons inventory for the two episodes. Emissions are day specific due to temperature and humidity corrections.

TABLE 3-3 Historical Episode Bioge nic Emissions (tons/day)
Day VOC Tonnage August 5, 1997 808 August 6, 1997 679 August 27, 1987 262 August 28, 1987 293Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 7 

### Future Baseline Emissions
The 2002, 2007, 2010, and 2020 baseline emissions are summarized in Table 3-4. Table 3-4 presents emissions for August 5, 1997 episode. Future-year emission estimation techniques are similar for both episodes. (Baseline emissions for 2002 are estimated from the 1997 inventory). Differences among the episodes, mainly due to differences in temperature-sensitive emissions, are less th an 50 tons/day or 5 percent. These inventories reflect the emissions resulting fro m increases in population and vehicle miles traveled (VMT), as well as the implementation of all rules a nd regulations adopted as of November 30, 2002. VOC and NO x baseline emissions decrease from the historical base year through the year 2020. This decreas ing trend in emissions reflects the implementation of current state and loca l air quality rules and regulations.



### Future Controlled Emissions
The control factors developed from the Controlled Emission Projection Algorithm (CEPA) program are applied to the future base year emissions to calculate the controlled emission inventories. Future-year contro lled emissions, estimated from the baseline emissions using the CEPA control factors, ar e given in Table 3-5. Table 3-5 presents emissions for August 5, 1997. Tw o control options for Basin NO x emissions in 2010 are proposed: Option-1, 529 tons/d ay (including emission reduc tions from federal sources and Option-2, 597 tons/day (e xcluding federal source reduc tions), respectively. These emissions are reduced from projected baseline levels of about 764 tons/day. Basin VOC episodic modeling emissions in 2010 are proposed to be controlled to about 314 tons/day for Option-1 and 317 tons/day for Option-2. These emissions are reduced from baseline levels of about 671 tons/day. Note that no future controlled emissions are provided for 2002 or 2007. Future controlled emissions are estimated to be equivalent to baseline values.



### EPISODE SELECTION
U.S. EPA guidelines suggest that the primar y meteorological episodes used for an ozone attainment demonstration be no more than ten years old. In general, this guidance is designed to attempt to keep the meteor ological episode current with the ongoing emissions trends and also to ensure that the attainment demonstration can benefit from state-of-the-science enhancements in da ta monitoring and em issions inventory developmentFinal 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 8 Table 3-4
Future Baseline Episode Emissions (tons/day)*

South Coast Air Basin Modeling Region** Year Source Type VOC NO x CO VOC NO x CO 2002 On-Road 374 642 3572 424 724 4030 Off-Road 186 339 1174 270 545 1634 Stationary 359 94 61 663 325 279 Total 919 1075 4807 1357 1594 5943

2007 On-Road 273 507 2506 429 774 3989 Off-Road 130 304 1031 197 480 1469 Stationary 307 81 67 622 325 287 Total 710 892 3604 1248 1579 5745

2010 On-Road 237 418 2203 372 648 3470 Off-Road 122 272 1012 184 430 1440 Stationary 312 74 69 629 334 300 Total 671 764 3284 1185 1412 5210

2020 On-Road 142 181 1054 231 298 1723 Off-Road 114 250 1024 170 370 1453 Stationary 365 76 79 718 390 322 Total 621 507 2157 1119 1058 3498 * Emissions are for the August, 5 1997 meteorological episode. ** Excludes emissions from Mexico.Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 9 TABLE 3-5 Future Controlled Episode Emissions (tons/day)*

South Coast Air Basin Modeling Region** Year Source Type VOC NO x CO VOC NO x CO 2010 On-Road 77 259 1739 122 405 2826 Option-1 Off-Road 56 195 980 119 354 1408 Stationary 181 75 68 497 332 299 Total 314 529 2787 738 1091 4533

2010 On-Road 77 270 1735 122 422 2819 Option-2 Off-Road 59 253 981 122 411 1409 Stationary 181 74 68 497 332 299 Total 317 597 2784 741 1165 4527

2020 On-Road 46 113 856 75 187 1421 Off-Road 55 169 994 111 289 1423 Stationary 214 76 78 568 390 323 Total 315 358 1928 754 866 3167 * Emissions are for the August 5, 1997 meteorological episode. ** Excludes emissions from Mexico.



### Southern California Ozone Study (SCOS97)
As briefly discussed in Chapter 1, the Southern California Ozone Study (SCOS97) [Jackson, et.al., 1998, Doislager, 1998, among others] measured oz one, precursor and meteorological data for several episode peri ods during the summer and fall of 1997. The monitoring program took place approximate ly one and a half years after the implementation of California Ph ase-II fuel reformulation. The goal of SCOS97 was to provide comprehensive air quality and meteor ological data for the purpose of evaluating state-of-the-science meteorological and ai r quality models for use in attainment demonstrations.
The intensive field monitoring during SCOS97 captured five multi-day ozone meteorological episodes. One of the epis odes occurred on a weekend, a desired prize since the weekend effect has been a major influence in Basin air quality in recent years. The primary meteorological episode intens ively monitored during the field campaign occurred during the period beginning August 3-7, 1997. August 5, 1997 produced the Basin's annual second maxi mum 1-hour average concentration (188 ppb). This meteorological episode has been selected for the current attainment demonstration.Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 10 One new candidate episode was considered fo r the attainment demonstration, (July 16, 1998), however, when evaluated using statistical ranking, the July 1998 episode, like the June 1985 episode, was determined to be rare event with an expe cted frequency of less than once four years. The cu rrent form of the federal ozone air quality standard allows for the standard to be exceed ed once per year to account for these rare meteorological events. As such, a peak oz one concentration due to mete orological conditions in the July 1998 episodes would not be accounted for in the current form of the standard.
One additional Southern California Air Qu ality Study (SCAQS) episode, August 26-28, 1987 is carried forward from the 1997 AQMP to provide continuity between AQMP attainment demonstrations. Table 3-6 lists the ozone meteorological episodes selected for the attainment demonstration with th e observed ozone maxima in each of the impacted air basins.

TABLE 3-6 Ozone Meteorological Episodes Used for the Ozone Attainment Demonstration
Episode Peak Concentration Peak (pphm) South Coast Mojave Desert Salton Sea. - Coachella Valley August 26-28, 1987 29 13 16 August 3-7, 1997 19 14 16


### Statistical Episode Ranking
A statistical model was developed to char acterize the ozone meteorological episodes relative to the seven year post fuel re formulation period ( 1996-2002). Multi-variate regression was conducted using the Basin 1-hour average ma ximum ozone concentration and surface and upper air mete orological data for 1996. The equation was generated from 184 days of data and it explained 77 percent of the total variance (R 2 = 0.77, R=0.89) the ozone distribution. The e quation was applied to the air quality and meteorological data for the seven-year peri od to predict Basin da ily maximum ozone and establish a daily ranking. The multiple lin ear regression included western U.S. surface pressure gradient data (wind forcing), th e vertical temperature, humidity and wind structure of the boundary layer, heights and thickness aloft and the number of hours of daylight. The upper air data was obtained from twice daily soundings at two California sites, San Diego (SAN, MY F and NKX), Oakland and Desert Rock, Nevada. The equation was used to rank the meteorological ep isodes is listed in Ta ble 3-7. Table 3-8 lists the rankings of the selected episode days.Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 11 TABLE 3-7
Regression Equation Used To Rank Meteorological Episodes

Variable Coefficient Units Time Intercept 29.853 N/A N/A Yesterdays 1-Hr Basin Max Ozone + 0.238 Pphm Variable Number of Hours of Daylight + 0.625 Hrs 0000-2300 PST LAX-SFO Surface Pressure Gradient - 0.161 Mb 0700 PST Day of Week + 0.393 Mon = 1 N/A San Diego 995 Mb Temperature - 0.413 o C 0400 PST San Diego 850 Mb Temperature + 0.496 o C 1600 PST San Diego 995 Mb Relative Humidity - 0.050 % * 100 1600 PST San Diego 950 Mb Relative Humidity + 0.028 % * 100 1600 PST Height of the 850 Mb Pressure Surface at Desert Rock - 0.018 m 0400 pst

Based on the 7-year period, the August 5 th episode day ranked as the 97 th most severe day, or the 96.21 th percentile of the distri bution (2557 cases). August 6 th ranked 100 th at the 96.09 th percentile. The July 16-17, 1998 couple ranked 5 th and 1 st at the 99.80 and 99.98 th percentile respectively. As an episode couple, no two consec utive days had as high a ranking throughout the seve n year period. In fact, on the afternoon of July 16, 1998, the height of the 500 Mb pressure surf ace reached 6000 meters above sea level. This extreme height value has been observed on only 4 days in the past 22 years. It is for these reasons (episode severity ranking as individual days and as a multiple day couple) that the July 16, 1998 meteorologica l episode was excluded from consideration in the ozone attainment demonstration.
The 22-year analysis is used to compar e the 1987 episode severity to the 1997 and 1998 episodes. The 1987 meteorological episodes were clearly less severe than August 1997 with August 27 th ranking 864 (the 89.25 th percentile out of 8035 days) and August 28 th ranking 436 (94.57 th percentile).Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 12 TABLE 3-8
Episode Ranking Applied to 7-Year Peri od (1996-2002) and 22-Ye ar Period (1981-2002)

Episode Max Ozone (ppb) 7-Year Ranking (1996-2002) 22-Year Ranking (1981-2002)

Rank Percentile Rank Percentile August 5, 1997 188 97 96.21 198 97.54 August 6, 1997 170 100 96.09 203 97.47 August 27, 1997 240 N/A N/A 864 89.25 August 28, 1997 290 N/A N/A 436 94.57 July 15, 1998 220 75 97.07 153 98.10 July 16, 1998 244 5 99.80 13 99.84 July 17, 1998 220 1 99.96 9 99.89 July 10, 2002 169 94 96.32 191 97.62 July 13, 2002 150 96 96.24 195 97.57 July 30, 2002 140 98 96.17 209 97.40 August 16, 2002 140 103 95.97 199 97.52



### Horie Classification
Based on the Horie episode classificati on scheme (Appendix V-P, 1989 AQMP), all days in the August 1997 and August 1987 episodes are categor ized as episode "Type-1" severity. "Type-1" is the most severe of the five classes of episodes in the classification system. The results of the statistical analys is indicate that there exists a broad range of conditions that make up the "T ype-1" day. While it is desi rable for the ozone modeling attainment demonstration to have meteorol ogical episodes from several categories, the "Type-1" meteorology has account ed for 52 percent of all da ys exceeding the federal 1- hour standard, averaged from 1996-2002. W ith the continuing trend of reduced precursor emissions, it is expected that the percentage of days exceeding the standard having "Type-1" meteorology will increase and ev entually become the sole path to high ozone concentrations in the Basin.



### Episodes Compared in the 2002 "Mid-Course" Assessment
Table 3-8 lists four days from 2002 that cl osely matched the ranki ng of the August 5, 1997 episode. They days fell in a tight ra nge, ranking between 94 a nd 103. Two of the days were slightly higher than August 5 th and two were slightly lower. In general, the spread (including August 5 th) ) was so tight that it is difficult to differentiate between theChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 13 days. The daily maximum ozone concentra tions observed on the f our days ranged from 140 to 169 ppb with an average of 150 ppb. The average of the observed daily maximum ozone concentrations from the four days that were similar to August 5, 1997 was used by the 2002 "mid-course" assessment to evaluate ozone simulated using 2002 emissions and the August 1997 meteorological episode.



### EPISODE CHARACTERIZATION
The meteorological setting characterizing the August 5-6, 1997 episode has been characterized as a part of the SCOS97 m onitoring program. The episode has been documented in a special edition of Atmo spheric Environment through a special secession of the AWMA Annual Conference, he ld in San Diego, June 1999. Cassmassi, 1999, and Jackson, et.al. 1999, provide characterization of the general meteorological episode profile used to forecast intensive monitoring, and the data characterizing the structure of the upper air wind and temperat ure monitoring and the program to profile the vertical ozone structure aloft (through 3000 m).
The following subsections examine the obser ved synoptic and mesoscale meteorological profiles as well as the ozone air quality th at was measured during the August 4-6, 1997 meteorological episode. A detailed discu ssion of the meteorological and air quality profile observed during the A ugust 27-28, 1987 meteorological ep isode is presented in Technical Report V-B of the 1994 AQMP.



### Background
The August 5-6 1997 meteorological ep isode resulted in the Basin 2 nd highest annual maximum observed ozone con centration 0.188 pbb, measured at Riverside-Rubidoux on August 5 th . The characterization of the ozone me teorological episode encompasses fivedays (August 3-7, 1997) to bracket the ai r quality episode. The episode took place during a period of the mid-summer that has one of the greatest frequencies for strong low level inversions, ample s unshine, warm temperatures, and moderate wind transport and ozone episodes.
The meteorological episode began on Sunday August 3 under a ridge of high pressure aloft with 500 mb heights measured by the 1200 UTC San Die go (NKX) sounding in excess of 5900 m each day. Weak onshore flow gave way to stagna nt winds through the middle of the episode ultimately resulting in a well developed coastal eddy beginning late on August 6 th and continuing into August 7 th . Winds observed on August 5 th

, illustrate a classic “South Route Transport” regime that has been identified as characteristic of past severe Basin oz one meteorological episodes (Keith, 1980).Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 14 Peak inland afternoon temperatures cres ted over 100 degrees Fa hrenheit on each day during the episode and Central Los Angeles c onsistently reached the mid to upper 90’s. The excessive regional surface temperatures and stagnant flow also contributed to a massive wildfire in the mountainous portions of eastern Ventura and southeastern Santa Barbara counties during the later part of the episode. Using the Horie episodic classification the five days were ranked by the following node categories: August 3 rd through August 6 th were categorized "Type-1". August 7 th was categorized a category "type-1A" (Node 10 on the CART analysis) due to the southerly flow that is consistent with transport north towards Ventura Count y. The episode types identified by the meteorologists to forecast the intensive monitoring period were consistent with the Horie scheme with the first four days being classi fied as a South Coast Air Basin maximum or second maximum and August 7 th being classified as a trans port day to Ventura and Santa Barbara counties.



### Synoptic Setting
On the afternoon of August 2 nd and throughout August 3 rd , a ridge of high pressure aloft developed over the southwest expanding westward from the Four Corners area of the southern Rocky Mountains. Heights at 500 mb reached 5900 m at Vandenberg AFB, San Diego (Miramar NAS) and Dese rt Rock (Nevada) on August 3 rd and remained above that level throughout the five day ep isode as a weak upper level trough receded into the Pacific Northwest. Figure 3-2 pres ents the 500 mb pressure height surface for 1200 UTC (0400 PST) on August 5 th where a double high pressure system is depicted. All of Southern California is enveloped w ithin the 5940 m contour with an analyzed local 5970 m high located west of the Basin over the Southern California Bight. The August 5 th afternoon 850 mb pressure surface (0000 UTC on August 6 th ) depicted in Figure 3-3 showed temperatur es of 28 degrees Celsius and higher over the Basin, indicative of strong subsiden ce generated by the high-pressure system. Winds along the coast at the 850 mb pressure surface (appr oximately 1500 m) were generally from the northwest for the bulk of August 5 th and 6 th . By August 7 th , the entire west coast was under the influence of high pressure aloft with only a trace of a short wave trough passing to the north through Washington and British Columbia.
At the surface, high pressure was slowly bu ilding in the Great Basin of Nevada pushing a thermal trough westward towards the coast of California. By the morning of August 4 th (1200 UTC) the thermal trough had enveloped California with a surface low analyzed near Yuma Arizona running northward to bis ect the state (Figure 3.4). This pattern continued until the early morning hours of August 7 th as a coast eddy began to develop as the thermal trough moved over the coas t. The coast eddy remained in place throughout the day as is evidenced by the presence of reporte d fog and overcast conditions in the coast plain and as well as the southerly flow.Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 15 

### Mesoscale Meteorology
The mesoscale winds, temperature and pressu re gradient fields for the August 3-6 th period were generally consiste nt throughout Southern Califor nia. The general profile shifted late on the 6 th to the 7 th to reflect the development of the coastal eddy. In general, skies were clear throughout the period with the exception of smoke over the Ventura area from the wildfire. All su rface pressure gradient fields (along the coast and inland towards the desert) were direct ed weakly offshore. Under th is type of regime, the sea breeze wind flow becomes less orga nized and often fails to penetrate deep into the Basin – let alone the desert areas. On August 4 th , surface winds were predominantly from the west through the coastal plain turni ng more west-southwesterly on the 5 th . By the afternoon of the 6 th , southerly flow begins to become evident in the flow field continuing with greater influence on the 7 th

. Average afternoon wind speeds ranged be tween 5 to 10 mph measured at SCAQMD monitoring stations during the period with only a few hours above 10 miles per hour being recorded in the afternoon hours in th e eastern SoCAB. Nighttime and morning winds were light and variable on all days during the epis ode with frequent calms and general speeds recorded at 5 mph or less through 1000 PST.
On August 5 th , winds were essentially calm in th e morning however the sea breeze came onshore over the central portion of the Basi n in response to excessive inland surface heating in Riverside County. The ma ximum temperature measured on the 5 th reached 113 degrees at the Riverside county fire station, 7 degrees warmer than the 4 th . The South Route Trajectory typically brings th e coastal emissions and brewing smog cloud over southern Los Angeles and Northern Or ange counties with transport through the Santa Ana Pass to the eastern portion of th e basin. Transport can be noted by a combination of pollution levels, temperature falls and humidity rises in the areas where the sea breeze front traverses. In the areas where the sea breeze has made its incursion an advection inversion with limite d mixing becomes established.

The base of the coastal 1200 UTC inversion was at or slightly above the surface throughout the episode. Morning inversion top temperatures ra nged from 27.8 to 33.6 degrees C with the peak transcending the morning of the 5 th through the morning of the 6 th . Despite the strong inversions, the th ermal trough over California caused surface temperatures to readily exceed 100 degree Fahrenheit and the inversion was partially broken on the 4 th and resulted in deep mixing in the inland valleys on the 5 th and 6 th . On all three days, the inversion was broken in the San Fernando Valley. Relative humidity values were below 20 percent during the daytime in modest inland areas with only the coastal zone experiencing 40 pe rcent or higher during the earlier periods of the day.Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 16 Figure 3-2
500 Mb Pressure Surface at 0400 PST on August 5, 1997



### Air Quality Profile
Ozone air quality reached the H ealth Advisory concentrations on two day in the episode with the peak observed value (188 ppb) occurring on the 5 th at Rubidoux. Several areas exceeded the federal 1-hour ozone standard at (11 locations) with Redlands, San Bernardino, and Mira Loma a ttaining Ozone Health Advisories. Areas such as Azusa, Pasadena, Glendora and Santa Cl arita that routinely experien ce higher values of ozone during episodic conditions were spared the brunt of the impact due to excessive daytime heating deepening the mixed layer. Overall, The peak concentra tions in the Basin reached 140 ppb on the 4 th in the Central San Bern ardino Mountains, 188 ppb at Rubidoux on the 5 th , 170 ppb and 150 ppb on the 6 th and 7 th respectively on both days in the Central San Bernardi no Mountains. On the 6 th , ozone transport was observed through the Newhall pass to the Santa Clarita ar ea and concentrations rose in Reseda and Ventura County as the co astal eddy developed.Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 17 Figure 3-3
850 Mb Pressure Surface at 1600 PST on August 5, 1997



### MODELING METHODOLOGY
The methodology used in mode ling ozone is presented next. Since much of the methodology is the same as th at used in the 1994 and 1997 AQMP, the reader is referred to Technical Reports V-A and V-B of the 1994 AQMP and Appendix V of the 1997 AQMP for a more complete discussion. Discu ssion here is limited to the areas in which the procedures used for the 2003 AQMP di ffer from those used for the 1994 and 1997 AQMPs. First the methods used to deve lop the inputs are discussed, then the performance of the model is described. This section includes a discu ssion of some of the uncertainties present in the modeling analysis.Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 18 Figure 3-4
Surface Pressure Contour Analys is at 0400 PST on August 4, 1997



### Model Input Preparation
The procedures for UAMAERO-LT input file prep aration are presented in this section. Many of the input to the UAM simulations were the same as were used in the previous AQMP ozone modeling attainment demonstr ations. The areas of model input preparation that differ from the past practice ar e discussed at length. In general, the majority of the input files have the same format and structure.
The SCOS97 meteorological data has undergone extensive quality assurance analyses. The meteorological data has been reviewed and flagged where questionable values occur. The Meteorological Wo rking Group of SCOS has reviewed the August 4-6, 1997 meteorological data set at length, comp aring wind fields to observational based conceptual models of th e episode. The upper air data has undergone additional extensive review by NOAA and STI under contract.Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 19 Modeling Domain
The UAM modeling region used to simula te 1-hour average ozone for the 2003 AQMP is presented in Figure 3-1. The area is commonly referred to as the "SCOS97 Modeling Domain" and it covers an ar ea extending from northern Mexi co to the southern portion of the San Joaquin Valley. The region extends 550 km in the east-west direction and 370 km in the north-south dire ction, beginning at the UTM location of 150 easting and 3580 northing. The horizontal extent of the dom ain used for the UAM analysis is larger than that used for the previous UAM 1997 AQMP simulations or for the current 2003 Draft AQMP UAMAERO-LT PM 10 modeling demonstration. Horizontal grid cell resolution was 5 km, as was used in previous UAM modeling applications for the Basin.
The vertical dimensions of the modeling dom ain are based on previ ous experience in UAM applications for the Basin and elsewher e. The height of the modeling domain for the UAM simulations was set to a constant 2000 m above ground level. Five spatially and temporally varying layers (based on the mixing height) are used.
Boundary, Top and Initial Air Quality Concentrations

A modified version of the EPA continen tal average boundary conditions "EPA-Clean" for gaseous pollutants was used as a st arting point for the boundary and model-top concentration assignment. Hydrocarbon speciation profiles developed for the 1994 AQMP [Technical Report V-B (1994) ] were used to specify the required species. The major adjustment to the "EPA-Clean" profile was to reduce the NO and NO2 concentrations (topcon) to 1. 0 and 2.0 part per trillion (ppt ). This set of boundary and top concentrations was refe rred as "ARB-Clean" conditions . The initial condition field was also derived from the monitored air quality data observed for the first day of the simulation. Table 3-9 lists the modified "ARB-Clean" boundary, top concentrations.
A simple vertical pollutant profile was a ssumed. The boundary cells below the mixing height were given the gr idded ground-level pollutant concentrations, and the concentrations in the boundary cells above this level were assumed equal to their corresponding value at the top of the modeling domain.
Future Boundary, Top and Init ial Air Quality Conditions
For the future year scen arios, the boundary, region t op and ambient air quality concentrations were rolled back based on the percentage reduction in emissions from 1997 base year to the projected emissions leve ls for future year of the simulation (2002, 2007, or 2010).Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 20 TABLE 3-9
Modified ARB-Clean Boundary and Top Concentrations
Species Units Boundary Top NO PPM 0.000001 0.000001 NO2 PPM 0.002 0.002

O3 PPM 0.04 0.04 OLE PPM 0.000276 0.000276 PAR PPM 0.0137 0.0137 TOL PPM 0.000164 0.000164 XYL PPM 0.00009 0.00009 FORM PPM 0.001928 0.001928 ALD2 PPM 0.000508 0.000508

ETH PPM 0.000468 0.000468 CRES PPM 0.00001 0.00001 OPEN PPM 0.00001 0.00001

PNA PPM 0.00001 0.00001 NXOY PPM 0.00001 0.00001

NO3 PPM 0.00001 0.00001 PAN PPM 0.00001 0.00001 CO PPM 0.2 0.2 HONO PPM 0.000001 0.000001 H2O2 PPM 0.00001 0.00001 HNO3 PPM 0.00001 0.00001

SO2 PPM 0.01 0.01 SO4 PPM 0.0001 0.0001 AERO PPM 3 3

Meteorological Scalars

The METSCALARS file contains information regarding the vertical structure of the modeling region, NO2 photolysis rate constants, and wate r concentrations. The six parameters in the METSCALARS file are spa tially constant values for each time interval described in the file.Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 21 • RADFACTOR NO2 photolysis rate constant (min-1)

• H2O water concentration (ppm)

• ATMOSPRESS atmospheric pressure

• CE exposure class

• TGRADBELOW temperature gradie nt below the mixing height

• TGRADABOVE temperature gradie nt above the mixing height

The RADFACTOR (or NO2 photolys is rate constant) inputs for the UAM were prepared using a theoretical solar flux calculation based on clear sky c onditions (Schere and Demerjian, 1977).

Water concentration is used in the UAM only for those chem ical reactions which contain water as a reactant. The water concentra tions were estimated from either dew-point temperatures or relative humidity and su rface ambient temperatures which were measured at meteorological monitoring stati ons and at weather observation stations.
The atmospheric pressure is used in converting molar units (emissions) to concentration units by volume. Since atmospheric pressure does not vary significantly over the SCAB and most of the region is near sea level, a value of one atm was used for all UAM simulations.
The exposure class, which is a numerical representation of the Pasquill stability category, is a function of solar zenith a ngle and cloud cover. The exposure class was derived from CALMET generated stability class.
Temperature gradients below and above th e mixing heights were determined from CALMET generated vertical temperature profile.
Meteorological Models
The CALMET meteorological model was the primary tool used to develop the meteorological fields. CALMET is a terrain following model that is designed primarily to develop three-dimensional wind, temperat ure and mixing height fields. For this application, CALMET was used to generate th e wind and vertical temperature structure. The CALMET mixing heights were evaluated however, the final mixing height fields were generated using a Holz worth (1964) approach (des cribed later). A more comprehensive discussion of the CALMET is provided in the wi nd field development section.Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 22 Temperature Fields
Surface Analysis
Three-dimensional temperature and humidity fields were developed from the available surface and upper air data using Poisson obj ective analysis techniques. The SCOS97 data set contained surface station data from approximately 200 reporting stations distributed throughout the mode ling domain. The surface st ations included data from the ambient air monitoring stations (all APCDs and AQMDs), FAA airport observations, CIMIS, RAWS and offshore buoy s ites. In some areas, sites were clustered in close proximity and as a result, the final temperature files were derived from a subset of the total SCOS97 archive. The hour ly surface fields were subjected to a 5-point filter to smooth gridded temperature variations.
Figures 3-5 presents the network of surfa ce meteorological stations used in the preparation of the meteorological input fi elds. Figures 3-6 through 3-11 show the surface temperature fields for 1000 PST and 1600 PST for August 4-6, 1997.

150 250 350 450 550 650 UTM Easting 3600 3700 3800 3900UTM Northing

Figure 3-5
Locations of Surface Monitoring Used in Preparation of Meteorological FieldsChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 23 Upper Air Analysis
The UAM analysis benefited from the most comprehensive set of upper air data collected in southern California for me teorological episode. Upper air wind and temperature data were continuously meas ured at 26 Radar Wind Profiler and Radio Acoustic Sounding System (RWP/RASS), at 6 ozone sonde sites, 9 rawinsonde sites and 2 Doppler acoustic sounding sites. Figure 3-12 shows the locations of the upper air monitoring sites. Sounding profiles were assu med to be representative of the upper air structure in the zone for a subjectively determined limited window of time. The temperature data were directly applied to th e vertical temperature field interpolation.

The RASS data needed conversion from virtua l temperature to sensible temperature. Interpolation of temperature was required to extend the profile from the top of the RASS signal to the top of the modeling domain. In terpolation was also require to extend the temperature profile from the surface to the first range gate where valid data was acquired. The conversion to sensible temp erature required the development vertical water vapor profiles for the m odeling domain. Water vapor tends to be a conservative element since and as such is a identifying characteristic of an air mass. A single air mass enveloped southern Ca lifornia during the August 1997 epis ode. As a consequence, the data from the rawinsonde and ozonesondes was sufficient to provide the time and space varying vertical moisture profile need ed for the temperature conversion.
Mixing Height Fields
Mixing was calculated using a Ho lzworth (1964) approach, which estimates the extent of buoyant vertical lifting of an air parcel based on the surface temperature of the air parcel and that of the environment lapse rate m easured by the morning and afternoon soundings and the modified RASS temperature profiles.
The hourly mixing heights were calculated, then analyzed and interpolated to a gridded format using a distance-weighted objective analysis. Surface temperature profiles from designated geographical areas were assigned to representative vertical temperature profiles. Hourly objective mixing height calculations mi xing within a zone were determined by calculating the interception of the hourly vertical temperature profile and the assumed dry adiabatic ascent of the surface air parcel. If temperature profiles for all 24-hours were not available for a geographical area then linear interpolation of temperature by height level be tween soundings or modified RASS profiles was used to recreate the vertical structure. The final mixing height fields we re smoothes using a 5- point filter. Mixing heights above ground le vel were restricted to a 2000 m maximum and a 100 m minimum. Figures 3-13 th rough 3-18 present the mid morning and afternoon mixing heights for th e August 4-6, 1997 episode.Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 24 Figure 3-6 Surface Temperature Contours and Ob servations 1000 PST, August 4, 1997

Figure 3-7 Surface Temperature Contours and Ob servations 1600 PST, August 4, 1997Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 25 Figure 3-8 Surface Temperature Contours and Obse rvations 1000 PST, August 5, 1997

Figure 3-9 Surface Temperature Contours and Ob servations 1600 PST, August 5, 1997Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 26 Figure 3-10 Surface Temperature Contours and Ob servations 1000 PST, August 6, 1997

Figure 3-11 Surface Temperature Contours and Ob servations 1600 PST, August 6, 1997Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 27 Figure 3-12
Upper Air Monitoring Network During the August 4-6, 1997 Mete orological Episode

Gridded Wind Fields
The CALMET meteorological model, was us ed to generate hourly gridded threedimensional wind fields for the UAM si mulations. CALMET is the companion meteorological model to the CALGRID air quality simulation model. CALMET consists of a diagnostic wi nd field module and micrometeorological module for the boundary layer. CALMET has options to calc ulate hourly gridded mixing heights and was also used in generating the upper air te mperature structure. There are separate boundary layer models for "over land" and "over water" grid cells. For "over land" grid cells, the energy balance method of Holtslag and van Ulden (1983) is used to compute hourly gridded fields of se nsible heat flux, surface friction velocity, Monin-Obukhov length, and convective velocity scale. Mixing heights are determined from the computed hourly surface heat fluxes and observed temp erature sounding using a modified Carson (1973) method based on Maul ( 1980). For "over water" grid cells, a profile technique based on air-sea temperature difference is us ed to compute the micrometeorological parameters in the marine boundary layer. Th e reader is referred to U.S. EPA et al. (1995) for a complete description of the CALMET meteorological model.Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 28 The diagnostic wind field module uses a two step approach for the computation of the wind fields (Douglas and Kessler, 1990). In th e first step, an initial-guess wind field is adjusted for the kinematic effects of terrain , slope flows, and terra in blocking to produce a "Step 1" wind field. The s econd step consists of an obj ective analysis procedure to introduce observational data into the "Step 1" wind field to produce a final wind field. An option is provided to a llow gridded prognostic wind fiel ds, developed by MM5, to be used by CALMET as the initial guess field. One drawback of inserting the MM5 output is the mismatch in the coordinate systems (UAM/CALMET on a UTM system and MM5 on a Lambert conformal grid). Merging output from the two models requires the data field conversion of either of either meteorology or emissi ons (which are generated on a UTM coordinate system). With the wea lth of observational data available from SCOS97, it was decided to use the objective data to serve as the first guess field.
Wind speed, wind direction, temperature, humidity, cloud cover, ceiling height, and surface pressure were extr acted from the SCOS97 extensive RWP, RASS and sodar network, sonde launches and hourly surface observati ons during the intensive monitoring periods. CALMET employs an inve rse-distance-squared or inverse-distance weighted interpolation to transform obser ved data into gridded fields of the meteorological variables for the specified leve ls and time. Interpol ation is controlled by the maximum radii of influence, number of sta tions to be used, and barriers. In this analysis barriers were positioned over the ridge lines of the Los Padr es, San Gabriel, San Bernardino, San Jacinto a nd Saddleback mountains.
Land use and land cover (LULC) data files that describe the vegetation, water, natural surface, and cultural feature on the land su rface was obtained from the United States Geological Survey. The parameter of soil h eat flux was increased from 0.25 to 0.80 for the urban land use. For agricultural, Range land and forest, the parameter of soil heat flux was increased to 0.5 from 0.15.
CALMET was run using 16 vertical layers, extending to 5000 m with 11 layers residing in the first 2000 m, three in the lowest 100 m. (Note that UAM domain top was set at 2000 m for the ozone attainment demonstra tion simulation). UAM layer-averaged winds were created from the CALMET out put using a layer matching scheme (UAMWND) developed by Dougl as et al. (1990), which weights surface layer wind influence to layers aloft on the basis of stability. For the UAM application, the 3- dimensional winds were conve rted to a 5-layer format using the UAM layer-matching scheme and the gridded matrix of hourly mixing heights.
.Additional post-processing techniques were se lectively applied to the UAM wind fields generated using one or more of the above methodologies. Th ese included the use of a 5- point filter to smooth a UAM wind field to dampen horizontal shear, and use of a filtering technique (which follows a profile suggested by O’Brien [1970]) to adjust UAM vertical velocities and dampen mass flow through the top of the modeling domain.Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 29 Figures 3-19 through 3-24 pr ovide the UAM layer-1 wi nds for 1000 and 1600 PST for August 4-6, 1997. Figures 3-25 through 3-30 provide the UAM layer-3 winds for the same time frame.



### Model Input Evaluation
The samples of the meteorological fields that are presented in the preceding sections are discussed in terms of "how well does the meteorology fit the conceptual models"? Given the amount of data acquired during the SCOS97 intensive monitoring program, it was anticipated that the objective analysis should be capable of providing a reasonable recreation of the conceptual model. The fo llowing sections address the fit of the model input data to the conceptual model.
Temperature Fields
Briefly, one can assess the August 1997 ep isode as being very warm on the 4 th and 5 th with a slight tendency towards cooling the afternoon of the 6 th . The temperature fields shown in Figures 3-6 through 3-11 were directly generate d from the densely monitored temperature observations. After noon temperatures between 35 and 40 o C are captured on the 4 th . Temperatures exceeding 40 o C are evident in the inland valleys from the mornings of the 5 th through the morning of the 6 th indicating the presence of the thermal trough along the coastal zone. Surface temp eratures are lower on the afternoon of the 6 th as the sea breeze under an eddy circulation pump cooler marine air inland. This pattern fits well with the conceptual model.
Mixing Height Fields
The mixing height fields pr esented in Figures 3-13 thr ough 3-18 indicated a general pattern of tight mixing gradients across the Basin on the first two days of the episode followed by a weak gradient on the 6th. On the 4 th , the eastern and western Basin are separated by the 800 m mixing he ight contour with the deserts clearly identified by the 1200 to 1500 m contour on the 4 th . Mixing on the 5 th is deeper with only the coastal zone having mixing less than 1000 m. Both the San Ferna ndo and San Gabriel Valleys have mixing heights exceeding the 1000m level. The desert on this day is essentially indistinguishable for the far eastern Basin with a 1800 m contour acting as an informal breakpoint separating the regions. Mixing on the 6 th is typically lower due to the developing eddy and the associ ated influx of cooler marine modified airflow. The broadly spaced contours show a more unifo rm level of mixing throughout the Basin, typically below 1000m. The gradient to th e desert occurs at about 1600 m contour on this day. The pattern of mixing heights is consistent with the evolution of the episode described by the conceptual model.Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 30 Figure 3-13 Mixing Heights 1000 PST, August 4, 1997

Figure 3-14 Mixing Heights 1600 PST, August 4, 1997Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 31 Figure 3-15 Mixing Heights 1000 PST, August 5, 1997

Figure 3-16 Mixing Heights 1600 PST, August 5, 1997Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 32 Figure 3-17 Mixing Heights 1000 PST, August 6, 1997

Figure 3-18 Mixing Heights 1600 PST, August 6, 1997Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 33 Figure 3-19 Level-1 UAM Wind Field 1000 PST, August 4, 1997

Figure 3-20 Level-1 UAM Wind Field 1600 PST, August 4, 1997Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 34 Figure 3-21 Level-1 UAM Wind Field 1000 PST, August 5, 1997

Figure 3-22 Level-1 UAM Wind Field 1600 PST, August 5, 1997Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 35 Figure 3-23 Level-1 UAM Wind Field 1000 PST, August 6, 1997

Figure 3-24 Level-1 UAM Wind Field 1600 PST, August 6, 1997Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 36 Figure 3-25 Level-3 UAM Wind Fields 1000 PST, August 4 1997

Figure 3-26 Level-3 UAM Wind Fields 1600 PST, August 4, 1997Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 37 Figure 3-27 Level-3 UAM Wind Fields 1000 PST, August 5, 1997

Figure 3-28 Level-3 UAM Wind Fields 1600 PST, August 5, 1997Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 38 Figure 3-29 Level-3 UAM Wind Fields 1000 PST, August 6, 1997

Figure 3-30 Level-3 UAM Wind Fields 1600 PST, August 6, 1997Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 39 Wind Fields

The winds at UAM levels 1 a nd 3 are presented to address the flow at the surface and aloft. Figures 3-19 thr ough 3-24 present the 1000 PST and 1600 PST level-1 surface winds. Figures 3-25 th rough 3-30 present the UAM level- 3 winds (first layer above the mixing height).
On the morning of the 4 th the surface winds depict a typical onshore flow pattern directed towards the San Gabriel Valley. By 1600, the transport pattern is primarily from west to east with the bulk of trans port through the San Gabriel Valley into San Bernardino and northern Riversid e Counties. Upper air flow is essential weak in the morning hours and mainly from the northwest. By afternoon, the level-3 winds indicate a westerly sea breeze across the Basin with some continued northwest flow elsewhere.
On the morning of August 5 th , surface winds are very light with a poorly organized onshore flow traversing Palos Verdes Peninsul a. There is a significant amount of weak along shore flow at the coast. Aloft at level- 3, weak drainage flow towards the coast is evident with some north easte rly flow inland and across the desert areas. This is consistent with the thermal trough making a move towards the coast and the "desertification" of the Basin is taking place. The drainage aloft with the weak north westerly along shore flow at the surface he lped to push the afternoon sea breeze to a southerly transport route though the cen tral Basin and Santa Ana Canyon.

The afternoon winds on the 5 th are onshore and westerly with the Elsinore convergence zone depicted in western Riverside County. The flow aloft at leve l-3 on the afternoon of the 5 th was generally out of the northwest. Th e top of the sea breeze flow over the central Basin and northern Orange Count y reinforce the surface flow pattern.
By the morning of the 6 th southerly wind flow is evident throughout the coastal zone as a eddy is forming in the Santa Monica Bight . The eddy is clearly evident through the southerly flow at level-3 in the morning, weakening somewhat in the afternoon. At the surface (level-1) in the after noon hours, the flow has taken a north route of transport. Under an eddy flow regime the sea breeze bi sects the Basin with one leg of the flow traversing San Fernando Valley and the resi dual sea breeze causing transport through Cajon Pass and into the San Be rnardino Mountains. This pattern is evident in the wind flow depicted by the winds. In general, the wind flow patterns throughout the episode are consistent with the conceptual model.Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 40 

### 1997 BASE-YEAR PERFOMANCE EVALUATION
For the evaluation of the pe rformance of UAM the modeling domain is separated into nine sub-regions or zones. Figure 3-31 depicts the sub-regi onal zones used for base-year simulation performance. The different zone s present unique air quality profiles. In previous ozone modeling atta inment demonstrations usi ng a smaller modeling domain, the number and size of the zones was different . Seven zones repres ented the Basin and portions of Ventura County, the Mojave De sert and the Coachella Valley. As a consequence, a direct overlap of all of the sub-regions does not exist.
For the current analysis the Basin is represen ted by three of the zones: Zone 3 – the San Fernando Valley, Zone 4 – th e Eastern San Gabriel, Ri verside and San Bernardino Valleys, and Zone 5 – the Los Angeles and Or ange County emissions source areas. Of the four areas, Zone 4 represents the Ba sin maximum ozone concentrations and the primary downwind impact zone. As such, th e priority in evaluating model performance is focus on Zone 4. The 1997 base-year re gional model performance for the August 5-6, 1997 and the August 27-28, 1987 episodes in Zones 3, 4, and 5 is pres ented in Tables 3- 10 to 3-12. The ratio of the predicted Basi n peak concentration (highest grid level concentration) compared to peak observed conc entration is repeated at the top of Tables 3-10 to 3-12 for reference to show the ove rall capability of the model to simulate maximum concentrations. The regional perfo rmance statistics are given in Attachment E. The performance goals for regional ozone are as follows:

Statistic for O 3 Criteria (%) Comparison Basis

Normalized Gross Bias ≤ ± 15 Paired in space and time Normalized Gross Error ≤ 35 Paired in space (+2 grid cells) and time Peak Prediction Accuracy ≤ ± 20 Unpaired in space and time
The performance statistics for oz one, and three precursors, n itrogen dioxide, nitric oxide and carbon monoxide are pr esented in each table. While an increased emphasis has been place on monitoring the differe nt component species of organic compounds through he Photochemical Assessment Monitoring Stati ons (PAMS) program only a limited number of sites were spread through the modeling domain. As a consequence, meaningful statistics could not be genera ted for all nine regions. Ca rbon monoxide is used as a surrogate of the organic compounds for this assessment.
Model performance criteria for nitrogen dioxide are listed in Technical Report VB of the 1994 AQMP. No criteria are available for 1-hour average carbon monoxide or nitric oxide.Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 41 Figure 3-31
Performance Evaluation Zones



### Statistical Evaluation
The August 1997 UAM ozone simulation met the unpaired peak model performance goal on August 5 th in all three zones. The unpaired peak model performance goal is met in zones 3 and 4 on August 6 th however zone 5 is over predicted. The gross error was met on the 5 th in each zone. The bias tends to be negative -- towards under prediction on the 5 th . The bias criterion is met on the 5 th in zone 4. In fa ct, the three performance criteria are met in zone 4 on August 5 th . There is a tendency to wards over prediction in all zones on the 6 th

. The results for the August 1987 ozone simula tion show a tendency for under prediction of the peak ozone on in all zones (w ith the exception of zone 3 on the 28 th ). The gross error and bias are achieved in each zone on the 28 th . While the perform ance statistics for the August 1987 episode are poorer than for the August 1997 episode, it is important to note that the current AQMP performance for th at episode is far better than the base performance for the same episode in the 1997 AQMP. In the 1997 AQMP only after doubling the overall on-road motor vehicle VOC emissions were the ozone performance criteria met.Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 42 TABLE 3-10 Comparative Performance Statistics for Zone 3
Statistic August 1997 August 1987 5 th 6th 27th 28th Ozone Threshold (pphm) 6.0 6.0 8.0 10.0 Ratio of Predicted Basin Peak to Peak Observed 1.05 1.14 0.94 1.08

Ratio of Unpaired Station Peaks 0.80 1.18 0.89 1.26

Systematic Bias (%) -20 6 -2 17 Gross Error (%) 32 44 22 27

NO 2 Threshold (pphm) 1.0 1.0 2.0 2.0 Ratio of Unpaired Station Peaks 0.44 0.46 1.25 0.91

Systematic Bias (%) -36 56 11 28 Gross Error (%) 50 59 35 42

NO Threshold (pphm) 1.0 1.0 2.0 2.0 Ratio of Unpaired Station Peaks 1.19 0.53 0.88 0.79

Systematic Bias (%) 43 -61 58 21 Gross Error (%) 110 85 130 85

CO Threshold (pptm)* 2.0 2.0 5.0 5.0 Ratio of Unpaired Station Peaks 0.35 0.54 1.14 1.05

Systematic Bias (%) -62 -47 39 63 Gross Error (%) 62 48 64 80

Bold indicates numbers meeting performance goals. * Note: No performance criteria for 1-hour average carbon monoxide and nitric oxide were available.Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 43 TABLE 3-11 Comparative Performance Statistics for Zone 4
Statistic August 1997 August 1987 5 th 6 th 27 th 28 th Ozone Threshold (pphm) 6.0 6.0 8.0 10.0 Ratio of Predicted Basin Peak to Peak Observed 1.05 1.14 0.94 1.08

Ratio of Unpaired Station Peaks 1.01 1.10 0.83 0.79

Systematic Bias (%) -4 18 -23 -1 Gross Error (%) 25 40 34 21

NO 2 Threshold (pphm) 1.0 1.0 2.0 2.0 Ratio of Unpaired Station Peaks 0.53 0.62 0.97 0.95

Systematic Bias (%) -40 -56 14 40 Gross Error (%) 51 58 57 68

NO Threshold (pphm) 1.0 1.0 2.0 2.0 Ratio of Unpaired Station Peaks 1.10 0.44 1.16 1.19

Systematic Bias (%) -31 -60 -26 -16 Gross Error (%) 90 81 61 61

CO Threshold (pptm)* 2.0 2.0 5.0 5.0 Ratio of Unpaired Station Peaks 0.58 0.36 1.11 0.97

Systematic Bias (%) -45 -48 7 38 Gross Error (%) 50 48 52 64

Bold indicates numbers meeting performance goals. * Note: No performance criteria for 1-hour average carbon monoxide and nitric oxide were available.Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 44 TABLE 3-12 Comparative Performance Statistics for Zone 5
Statistic August 1997 August 1987 5 th 6 th 27 th 28th Ozone Threshold (pphm) 6.0 6.0 8.0 10.0 Ratio of Predicted Basin Peak to Peak Observed 1.05 1.14 0.94 1.08

Ratio of Unpaired Station Peaks 1.11 1.24 0.85 0.91

Systematic Bias (%) -23 -43 -19 -4 Gross Error (%) 32 62 21 19

NO 2 Threshold (pphm) 1.0 1.0 2.0 2.0 Ratio of Unpaired Station Peaks 0.60 0.82 1.14 1.70

Systematic Bias (%) 16 12 57 113 Gross Error (%) 44 43 62 115

NO Threshold (pphm) 1.0 1.0 2.0 2.0 Ratio of Unpaired Station Peaks 1.85 0.83 1.90 2.21

Systematic Bias (%) 122 -1 70 73 Gross Error (%) 162 103 105 114

CO Threshold (pptm) 2.0 2.0 5.0 5.0 Ratio of Unpaired Station Peaks 1.13 1.50 1.39 2.26

Systematic Bias (%) 37 -20 70 94 Gross Error (%) 62 61 80 102

Bold indicates numbers meeting performance goals. * Note: No performance criteria for 1-hour average carbon monoxide and nitric oxide were available.Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 45 The performance of the nitrogen dioxide simulation for the August 1997 episode indicates that the simulation performed reasonable well in capturing the peak concentrations in the emissions source areas in zone 5. The peak performance criteria were also met in zones 3 a nd 4 on both days. Under-predi ction of the peak nitrogen dioxide concentrations was noted on both days in zone 3. In general, nitrogen dioxide concentrations were over predicted in th e zone 5 emissions source areas and under predicted in downwind zone 4. This pattern was repeated by the carbon monoxide performance. However, all zones over predict n itric oxide (with the exception of zone 4 on the 6 th ) with the greatest over prediction occurri ng in zone 5. Both zones 3 and 4 experienced a negative bias in nitrogen dioxide and carbon monoxide performance on August 5 th . Nitric oxide concentrations showed a large positive bias in zones 3 and 5 and a nominally positive bias in zone 4. That day was ex ceedingly hot and resulted in early, deep mixing of the atmosphere that appears to have diluted the emissions contribution. Zone 5, the coastal emissions source area consistently over predicted the concentrations of nitrogen di oxide and to a greater exte nt nitric oxide and carbon monoxide.
For the 1987 episode, the perform ance for nitrogen dioxide for zones 3 and 4 was within the performance criteria for unpaired peak pred iction and bias. In general, the tendency was towards over prediction. The nitric oxide and carbon monoxide performance for zones 3 and 4 on August 27 th and August 28 th were similar with good peak prediction (some under prediction) and a slight bias towards overall over prediction. The tendency for zone 5 for was for significant over pred iction of nitrogen dioxi de, nitric oxide and carbon monoxide.



### Graphical Evaluation
Figures 3-32 through 3-35 show the tile plots of predicted maximum ozone for the each day of the August 5-6, 1997 and August 27-28, 1987 ozone si mulations. Figures 3-36a through 3-36q show the station diurnal plots of predicted and observed ozone. Similar diurnal plots for the precursor variables, hour ly ozone isopleths for and all scatter plots of performance and residuals evaluations fo r the August 1997 episode are presented in Appendix A. While the emissions inventory for the 1987 episode has changed, and that change is reflected in the statistical perform ance evaluation, the reader is referred to Technical Report V-B of the 1994 AQMP for an extensive graphical assessment of the for the August 1987 episode.Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 46 Figure 3-32

UAM Simulated Maximum 1-Hour Average Ozone, August 5, 1997Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 47 Figure 3-33

UAM Simulated Maximum 1-Hour Average Ozone, August 6, 1997Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 48 Figure 3-34

UAM Simulated Maximum 1-Hour Average Ozone, August 27 1987Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 49 Figure 3-35

UAM Simulated Maximum 1-Hour Average Ozone, August 28, 1987Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 50 Figure 3-36a
UAM Simulated Maximum 1-Hour Averag e Ozone (Solid Line) Vs. Observed (Squares): August 3-7, 1997 Ozone Me teorological EpisodeChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 51 Figure 3-36b
UAM Simulated Maximum 1-Hour Averag e Ozone (Solid Line) Vs. Observed (Squares): August 3-7, 1997 Ozone Me teorological EpisodeFinal 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 52 Figure 3-36c
UAM Simulated Maximum 1-Hour Averag e Ozone (Solid Line) Vs. Observed (Squares): August 3-7, 1997 Ozone Me teorological EpisodeChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 53 Figure 3-36d
UAM Simulated Maximum 1-Hour Averag e Ozone (Solid Line) Vs. Observed (Squares): August 3-7, 1997 Ozone Me teorological EpisodeFinal 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 54 Figure 3-36e
UAM Simulated Maximum 1-Hour Averag e Ozone (Solid Line) Vs. Observed (Squares): August 3-7, 1997 Ozone Me teorological EpisodeChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 55 Figure 3-36f
UAM Simulated Maximum 1-Hour Averag e Ozone (Solid Line) Vs. Observed (Squares): August 3-7, 1997 Ozone Me teorological EpisodeFinal 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 56 Figure 3-36g
UAM Simulated Maximum 1-Hour Averag e Ozone (Solid Line) Vs. Observed (Squares): August 3-7, 1997 Ozone Me teorological EpisodeChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 57 Figure 3-36h
UAM Simulated Maximum 1-Hour Averag e Ozone (Solid Line) Vs. Observed (Squares): August 3-7, 1997 Ozone Me teorological EpisodeFinal 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 58 Figure 3-36i
UAM Simulated Maximum 1-Hour Averag e Ozone (Solid Line) Vs. Observed (Squares): August 3-7, 1997 Ozone Me teorological EpisodeChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 59 Figure 3-36j
UAM Simulated Maximum 1-Hour Averag e Ozone (Solid Line) Vs. Observed (Squares): August 3-7, 1997 Ozone Me teorological EpisodeFinal 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 60 Figure 3-36k
UAM Simulated Maximum 1-Hour Averag e Ozone (Solid Line) Vs. Observed (Squares): August 3-7, 1997 Ozone Me teorological EpisodeChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 61 Figure 3-36l
UAM Simulated Maximum 1-Hour Averag e Ozone (Solid Line) Vs. Observed (Squares): August 3-7, 1997 Ozone Me teorological EpisodeFinal 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 62 Figure 3-36m
UAM Simulated Maximum 1-Hour Averag e Ozone (Solid Line) Vs. Observed (Squares): August 3-7, 1997 Ozone Me teorological EpisodeChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 63 Figure 3-36n
UAM Simulated Maximum 1-Hour Averag e Ozone (Solid Line) Vs. Observed (Squares): August 3-7, 1997 Ozone Me teorological EpisodeFinal 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 64 Figure 3-36o
UAM Simulated Maximum 1-Hour Averag e Ozone (Solid Line) Vs. Observed (Squares): August 3-7, 1997 Ozone Me teorological EpisodeChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 65 Figure 3-36p
UAM Simulated Maximum 1-Hour Averag e Ozone (Solid Line) Vs. Observed (Squares): August 3-7, 1997 Ozone Me teorological EpisodeFinal 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 66 Figure 3-36q
UAM Simulated Maximum 1-Hour Averag e Ozone (Solid Line) Vs. Observed (Squares): August 3-7, 1997 Ozone Me teorological EpisodeChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 67 On August 5 th , the peaks are nominally under pred icted and tend to lag the observed concentrations in the San Fe rnando Valley and West L.A. ar eas. The simulation tends to under predicted observations in the San Gabriel Valley but and has a mixed scorecard for the coastal-metropolitan areas fitting the observed pattern from Long Beach to Anaheim with a slight lag in timing at La Habra and El Toro. In general, the eastern Basin stations have a better fit of the observed distributi on with Rubidoux being slightly under predicted and Elsinore and Temecula being over predicted with a lag in the maximum prediction. The tile plot (Figure 3-32) shows a maximum impact occurring in southwestern Riverside and th e northern tip of San Diego C ounty. The displacement in the maximum predicted concentration may refl ect the impact of biogenic emissions in the Santa Ana Mountains. Another possible re ason may be a subtle shift in the onshore flow that may have pushed the pollutant cloud too far south, missing the traverse through the Santa Ana Canyon. Regardless, peak concentrations in the primary impact zone of Riverside and San Bernardi no Counties are well represented.

On the 6 th , concentrations of ozone are over pred icted in the coastal and near valley portions of Ventura county in response to the eddy circulati on. The tile plot (Figure 3- 33) shows a hot spot in the northeastern por tion of Ventura County relating to a brush fire that erupted during the episode. Ve ry little ozone was generated in the coastmetropolitan areas. The inland valleys generated the appropriate maximum concentrations but the timing la gged observations. What show in the tile plot is the split in the impact zone in response to the bifu rcation of the surface wind trajectories under the eddy circulation.
Briefly, the tile plots for August 27 and A ugust 28, 1987 (Figures 3- 34 and 3-35) depict primary ozone impacts in the eastern San Ga briel Valley and east Basin (predicted and observed concentration exceeding .020 ppm) a nd secondary impact to the San Fernando Valley. The level of the predicted impa ct is consistent with observations



### Effect of Emissions Uncertainties

Great effort was undertaken in the SCOS 97 program and the ensuing updates to the mobile and day specific point and biogenic inventories to remedy may of the problems identified in prior AQMP modeling attainment demonstrations. Aircraft and airport operations were thoroughly reviewed and inventoried. Shipping transits into the Ports of Los Angeles and Long Beach were carefully logged and shipping la ne transits up and down the coast were logged fo r the major vessels. The biogenic emissions inventory under went significant modificati on and resulted in several pe er review papers outlining the inventory process. A whole revamp of the emissions surrogates used to distribute areas source emissions was conducted as well.Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 68 Of the inventory upgrades, none had as much impact as the revisions to ARB's on-road emissions program EMFAC 2002 and the development of an Off-Road companion model. The net impact of EMFAC2002 was to raise the absolute tonnage of NOx and VOC in the mobile source emissions inventory. For example, the Basin totals for VOC and NOx for the August 28, 1987 episode increased from 1969 and 1379 tons TPD in the 1997 AQMP to 2446 and 1846 TPD for the cu rrent effort. While VOC emissions rose 24 percent NOx emissions rose by a greater 34 percent margin. Many of the complaints of the episode development in the 1994 and 1997 episode was that there existed too much NOx relative to the amount of VOC in the domain. The upgrade to the inventories may have corrected several of the fa ults in the previous analyses but the ratio of VOC to NOx remained in favor of ozone titration in the coastal emissions region.
The higher relative amounts of NOx in the inventory may be a cause for the bias towards over prediction of NOx in Zone 5 and may have affected the model performance not only for UAM but for CALGRID and CAMx. UAM deposition term s will remove NOx at a fast rate relative to the response of se veral of the other air quality simulation models evaluated including CALGRID and CAMx. (This was confirmed by the preliminary performance evaluations of CALGRID and CA Mx which are not presented in this discussion). Overall, the net amount of NOx deposition depos ited by the UAM is greatest with CALGRID coming in second place. The CAMx net NOx deposition was substantially lower. The impact of grater deposition may have l ead to higher downwind ozone formation (possible as high as 10 ppb) and alterations in the timing of the formation.
Several additional factors resulting from the use of the EMFAC2002 and Direct Transportation Impact Model (DTIM4) to gene rate grid level mobile source emissions may have altered the VOC to NOx ratio in th e Basin. First, there exist differences between the two models in the numbers of trips and lengths of trips inferred by the regional transportation model output. More numerous starts and stops lead to greater VOC emissions from vehicle use and standi ng evaporative loss. Similarly, speed impacts the NOx emissions, especially from heavy duty diesels. Differences between the emissions models in how the truck speed factors are assigned may have lead to an overestimation of NOx. These aspects of the emissions inventory generation were identified in the development process and some corrections to the evaporative loss calculations were made. In addition a se nsitivity simulation was run with increased VOC and lower NOx that would be expected to occur if truck speeds were reduced. The net impact also raised the predicted am ount of ozone formed in the Basin.
Other areas of the inventory uncertainty may have impacted the UAM (and other models) performance including the assignment of surrogates used to distribute emissions through the Basin, and the sub-county dist ribution of vehicles by age. Several sensitivity simulations were conducted using emissions fa ctors generated by EMFAC2002 using a grid level characterizati on of the passenger vehicle age with eachChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 69 county. The analysis was designed to atte mpt to place older, high emitting vehicles in the general areas where they ope rate. There are drawbacks to this assumption in that the average trip distance in the Basin exceeds one grid length and can easily transverse a county line. The sensitivity analyses are ongoing and preliminary re sults suggest some changes in the ozone simulation model perform ance. However, the net impact would be minor, less than the 10 ppb identified by deposition terms.
The biogenic inventory is also subject to uncertainties due to the critical roll daily temperature and humidity has in the estimation of the emissions. This is clearly evident in the day-to-day variation in total emissions over the three day 1997 episode, and in the difference in the estimated emissions be tween 1987 and 1997. Also the speciation profile of the hydrocarbons emanating from the biogenic mass is a source of uncertainty, particularly for the SAPRC99 chemistry. Fi nally, the episodes take place in August and it is difficult to assess cumula tive stress on the biomass over the season and what impact did the stress have on daily emissions.

While the uncertainties exist in this analysis, the overall baseline performance of UAM is significantly better than the unadjusted UAM performance presented in the 1994 and 1997 ozone attainment demonstr ation plans. Additional stress tests on the August 1997 ozone meteorological episode are presented later in this chapter.



### MID-COURSE OZONE AIR QUALITY EVALUATION
As discussed in Chapter 1 and earlier in th is chapter, a "mid-course" evaluation of UAM performance was conducted using the 2002 proj ected baseline emissions inventory and the August 1997 meteorological ep isodes. The "mid-course" ev aluation is a weight of evidence tool that is used to demonstrat e that the model simulation is responding to changes in the emissions trend. The ability of the model to simulate ozone concentrations for days having a similar mete orological profile to those included in the meteorological episode for an independent set of emissions is a powerful statement that the simulations is reasonable and that the emi ssions trend is on the correct track. A oneto-one correspondence is not expected since the days in 2002 are not exact duplicates of the 1997 and 1987 episode days.
For this mid-course analysis, four days were identified in 2002 that ranked within ± 6 of the August 5, 1997 based on the 7-year ranki ng algorithm. The average observed ozone concentration for the four days (two ranke d above and two ranked below) was 150 ppb. The process was repeated for August 6 th using the 7-year ranki ng with the caveat of selecting the two days most closely ranked above and belo w the episode day ranking. For the 1987 episode, the process was repeated but the 22-year ranking was used as a classification. The tightest grouping of days ranked in 2002 that were similar to those in either episode occurred for Augus t 5, 1997 and August 6, 1997.Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 70 The simulation was conducted using the 2002 baseline emissions (grown from 1997) and adjusted boundary conditions. Table 3-13 summarizes the simulation and Figures 3-37 through 3-40 depict the tile plots of predicte d 1-hour maximum ozone. In general, the peak values of tend to be slightly over predicted for the 2002 4-day average observed daily maximum ozone concentrations. Only one of the four simulated Basin maximum days falls within the range of observations on the four da ys in 2002 that comprise the corresponding average day. Ho wever, the peak predicted ozone concentration (170 ppb for the August 5, 1997 episode) is compar able with the observed 2002 annual Basin maximum concentration of 169 ppb.
Little change in the spatial distribution of pr edicted Basin maximum ozone is depicted in the tile plots suggesting no radical changes have taken place in the relative contributions of VOC, NOx and carbon monoxide emissions since the base year.

TABLE 3-13
2002 Mid-Course Simulation Results

Episode Day UAM Predicted (ppb) 4-Day 2002 Historical Average Ozone (ppb) Range of Observations for Comparable days in 2002 (ppb) August 5, 1997 170 150 140 - 169 August 6, 1997 168 140 130 - 150 August 27, 1987 126 123 100 - 140 August 28, 1987 149 115 110 - 120Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 71 Figure 3-37
2002 UAM Simulated Maximum 1-Hour Average Ozone for the
August 5, 1997 Ozone Me teorological EpisodeFinal 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 72 Figure 3-38
2002 UAM Simulated Maximum 1-Hour Average Ozone for the
August 6, 1997 Ozone Me teorological EpisodeChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 73 Figure 3-39
2002 UAM Simulated Maximum 1-Hour Average Ozone for the
August 27, 1987 Ozone Me teorological EpisodeFinal 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 74 Figure 3-40
2002 UAM Simulated Maximum 1-Hour Average Ozone for the
August 28, 1987 Ozone Me teorological EpisodeChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 75 

### OZONE AIR QUALITY PROJECTIONS

UAM simulations were conducted for the futu re year base emission scenarios (2007, 2010 and 2020), and future year controlled scenarios (2007, 2010 [two-options], and 2020). Historical year modeling and mode l performance evaluation are discussed earlier. The impact of base and controlled em issions on ozone air qua lity is projected for all modeling episodes for the years 2007 2010 and 2020. The baseline and controlled emission projections for the historical and futu re years are given in Tables 3-2, 3-4 and 3-5.



### Projection of 2007 Air Quality
One major component of the 2003 AQMP modeli ng attainment demonstration addresses the issue of transport of oz one and precursor pollutants into the Coachella Valley, Antelope Valley, South Central Coastal Air Basin and Mojave Dese rt. The attainment year for each of these areas is 2007.
Focused UAM-predicted Coachella Valley ma ximum ozone concentration maps for the year 2007 are presented in Figures 3-41 th rough 3-44 for each day of the two modeling episodes. For the 2007 projection, the contro lled emissions scenario is presented. Emission reductions th rough 2007 are expected to take place through exiting established control measures and reductions in m obile source emissions as projected by EMFAC2002. By 2007, all areas of the Coach ella Valley demonstrate attainment of the federal ozone standard. Table 3-14 lists th e 2007 predicted air quality for the Coachella Valley, the Basin, and its ne ighboring transport partners.
The projected 2007 air quality for all non-Basin ar eas indicates that ozone is expected to meet the federal standard. UAM simulations for three of the ep isode days modeled indicated that predicted ozone concentra tions will be below the 124 ppb. The UAM simulation for the August 6 th episode indicated that a limited number of grid cells adjacent to the Basin, north of Cajon Pa ss transecting both Antelope Valley and the Mojave Desert, would exceed 124 ppb. (A 148 ppb maximum predicted grid cell ozone concentration was project for the Mojave De sert). However, the August 6th base-year UAM simulation over predicted ozone concentr ations at neighboring stations Hesperia and Victorville by an average of 33 percent and Lancaster in the Antelope Valley by 71 percent. (CALGRID, which under predic ted the base-year Basin maximum by 12 percent, also over predicted in this portion of the high desert by 9 percent for the same day). By adjusting the 2007 UAM simulati on in the local areas for the base-year over prediction, the estimated Mojave Desert im pact is lowered to 111 ppb and the Antelope Valley impact to 99 ppb. This correction is c onsistent with the proj ected is consistent with the direct UAM simulation for the remaining three episode days.Final 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 76 TABLE 3-14
UAM Simulated 2007 Maximum Oz one: Controlled Emissions

Episode Day Basin Coachella Valley Antelope Valley Mojave Desert VenturaSouth Central

Coast August 5, 1997 145 122 92 118 89 August 6, 1997 151 83 141 (99)* 148 (111)* 106 August 27, 1987 115 94 99 115 101 August 28, 1987 138 83 105 119 103

* Concentration for the high desert inside the brackets is the scaled value to adjust for systematic over prediction in the base yearChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 77 Figure 3-41

2007 UAM Simulated Controlled Maximum 1-Hour Average Ozone for the August 5, 1997 Ozone Me teorological EpisodeFinal 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 78 Figure 3-42

2007 UAM Simulated Controlled Maximum 1-Hour Average Ozone for the August 6, 1997 Ozone Me teorological EpisodeChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 79 Figure 3-43

2007 UAM Simulated Controlled Maximum 1-Hour Average Ozone for the August 27, 1987 Ozone Me teorological EpisodeFinal 2003 Appendix V: Modeling and Attainment Demonstrations

V-3- 80 Figure 3-44

2007 UAM Simulated Controlled Maximum 1-Hour Average Ozone for the August 28, 1987 Ozone Me teorological EpisodeChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 81 

### Projection of 2010 Air Quality

The UAM was simulated for 2 010 baseline and controlled emissions (two options) for the two modeling episodes. The two control em issions control options reflect the degree of implementation of federal control commitments in 2010. Option-1 assumes emissions reductions from federal sources . Option-2 assumes no emissi ons reductions from federal sources. Table 3-15 summarize s the 2010 baseline and future year predicted maximum ozone concentrations. Figures 3-45 thro ugh 3-48 depict the baseline 2010 ozone simulations without the projected implementa tion of additional controls. Figures 3-49 through 3-52 depict the baseline 2010 oz one simulations with the projected implementation of control strategy Option-1. Figures 3-53 through 3-56 depict the baseline 2010 ozone simulations with the pr ojected implementation of control strategy Option-2.
Without implementation of th e projected control strategy options, the Basin will not meet the federal ozone standa rd. The Basin however will me et the federal 1-hour ozone standard in 2010 w ith the implementation of the e ither control strategy option.

TABLE 3-15
2010 UAM-Simulated Maximum Ozone: Baseline and Controlled Emissions

Episode Day 2010 UAM Predicted Baseline Basin Maximum Ozone (ppb) 2010 UAM Predicted Controlled Basin Maximum Ozone

Option-1 (ppb) 2010 UAM Predicted Controlled Basin Maximum Ozone

Option-2 (ppb) August 5, 1997 153 123 123 August 6, 1997 146 120 124 August 27, 1987 120 98 98 August 28, 1987 136 111 112Final 2003 Appendix V: Modeling and Attainment Demonstrations

___________________ _____________________ __________________ ________________ V-3-82 Figure 3-45

2010 UAM Simulated Baseline Maximu m 1-Hour Average Ozone for the August 5, 1997 Ozone Meteorological EpisodeChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 83 Figure 3-46

2010 UAM Simulated Baseline Maximu m 1-Hour Average Ozone for the August 6, 1997 Ozone Meteorological EpisodeFinal 2003 Appendix V: Modeling and Attainment Demonstrations

___________________ _____________________ __________________ ________________ V-3-84 Figure 3-47

2010 UAM Simulated Baseline Maximu m 1-Hour Average Ozone for the August 27, 1987 Ozone Meteorological EpisodeChapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 85 Figure 3-48

2010 UAM Simulated Baseline Maximu m 1-Hour Average Ozone for the August 28, 1987 Ozone Meteorological EpisodeFinal 2003 Appendix V: Modeling and Attainment Demonstrations

___________________ _____________________ __________________ ________________ V-3-86 Figure 3-49

2010 UAM Simulated Controlled Maximu m 1-Hour Average Ozone for the August 5, 1997 Ozone Meteorological Episode--Option-1Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 87 Figure 3-50

2010 UAM Simulated Controlled Maximu m 1-Hour Average Ozone for the August 6, 1997 Ozone Meteorological Episode--Option-1Final 2003 Appendix V: Modeling and Attainment Demonstrations

___________________ _____________________ __________________ ________________ V-3-88 Figure 3-51

2010 UAM Simulated Controlled Maximu m 1-Hour Average Ozone for the August 27, 1987 Ozone Mete orological Episode--Option-1Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 89 Figure 3-52

2010 UAM Simulated Controlled Maximu m 1-Hour Average Ozone for the August 28, 1987 Ozone Mete orological Episode--Option-1Final 2003 Appendix V: Modeling and Attainment Demonstrations

___________________ _____________________ __________________ ________________ V-3-90 Figure 3-53

2010 UAM Simulated Controlled Maximu m 1-Hour Average Ozone for the August 5, 1997 Ozone Meteorological Episode--Option-2Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 91 Figure 3-54

2010 UAM Simulated Controlled Maximu m 1-Hour Average Ozone for the August 6, 1997 Ozone Meteorological Episode--Option-2Final 2003 Appendix V: Modeling and Attainment Demonstrations

___________________ _____________________ __________________ ________________ V-3-92 Figure 3-55

2010 UAM Simulated Controlled Maximu m 1-Hour Average Ozone for the August 27, 1987 Ozone Mete orological Episode--Option-2Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 93 Figure 3-56

2010 UAM Simulated Controlled Maximu m 1-Hour Average Ozone for the August 28, 1987 Ozone Mete orological Episode--Option-2Final 2003 Appendix V: Modeling and Attainment Demonstrations

___________________ _____________________ __________________ ________________ V-3-94 What is evident in Figures 3- 45 through 3-56 is that the pr ojected location of the peak concentration for the two primary days (Aug ust 5, 1997 and August 28, 1987) regardless of control option selected is western Rivers ide County. This is consistent with the location of the future year maximum concentrations projected in previous AQMPs. For the August 6, 1997 episode the 2010 peak occurs along th e Los Angeles-Ventura County line. The reduction in emissions from ba seline does not out weigh the transport influence of the coastal eddy . The 2010 controlled emissi ons simulations for August 27 shift the area of maximum ozone into the high desert, however maximum ozone concentrations predicted to be below 100 ppb.



### Projection of 8-Hour Average Ozone Air Quality for 2010

The form of the new ozone standard that is expected to be implemented in 2005 addresses an 8-hour average c oncentration of ozone. The fo rm of the standard is based on a multiple year average of 4- higher 8-hour c oncentrations at a given site. No daily 8- hour ozone standard exists however a general cu t point used as an e quivalent standard is 84 ppb. The 8-hour average co ncentrations have been report ed to EPA by the District for the past several years and the District's forecast program issues daily predictions using the 8-hour average base Air Quality Index. EPA has been accumulating the 8-hour average data in an effort to develop new design values for future ozone attainment classification. The UAM simu lations for 2010 were evaluate d to determine the projected maximum 8-hour concentrations and determ ine whether there wo uld be a need for additional emissions reductions to meet the new standard.
The UAM predicted ozone distribution for 2 010 baseline and controlled emissions (two options) for the two modeling episodes wa s used to generate 8-hour average concentrations. Table 3-16 summarizes the 2010 baseline and future year predicted 8- hour average maximum ozone concentrations.
With implementation of the projected contro l strategy options, the Basin will not meet the federal 8-hour ozone standard in 2010. Future additional emissions controls will be required to assure attainment of the 8-hour standard.Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 95 TABLE 3-16 2010 UAM-Simulated Maximum 8-Hour Average Ozone: Baseline and Controlled Emissions

Episode Day 2010 UAM Predicted Baseline Basin Maximum Ozone (ppb) 2010 UAM Predicted Controlled Basin Maximum Ozone

Option-1 (ppb) 2010 UAM Predicted Controlled Basin Maximum Ozone

Option-2 (ppb) August 5, 1997 120 101 98 August 6, 1997 127 107 108 August 27, 1987 100 84 82 August 28, 1987 127 104 105



### Projection of 2010 Air Quality fo r Alternate Emissions Scenarios
As part of the AQMP process, a CEQA eval uation is required to test the impacts of alternative emission reduction strategy on futu re year air quality. For the 2010 ozone attainment demonstration, four a lternate strategies were proposed:

• Alt.-1: No Project Taking Place.

• Alt.-2b: Lower VOC (~ 250 TPD) with Control Option-2.

• Alt.-3: Lower VOC (~250 TPD) with Control Option-1.

• Alt.-4 Least amount of Toxic VOC Emissions Option. .
The August 1997 and August 1987 episodes were simula ted for the four alternate emissions scenarios. Table 3-17 summari zes the Basin VOC and NOx emissions and UAM predicted maximum ozone concentrations for the primary day in each episode for the four 2010 alternate emission scenarios.
If the control strategies identified by the 2003 AQMP are not implemented (Options 1 and 2) the Basin will not meet the 1-hour average ozone fe deral standard. The BasinFinal 2003 Appendix V: Modeling and Attainment Demonstrations

___________________ _____________________ __________________ ________________ V-3-96 will meet the federal 1-hour ozone standard w ith the lower VOC totals of the Alt.-2b, Alt.-3 and Alt.-4 emissions scenarios.

Table 3-17
Summary of Results from 2010 Alternative Emissions Scenarios

August 1997 August 1987 Emissions

5th 6th 27th 28th Alternative

VOC (tpd) NO x (tpd) O 3 (pphm) O 3 (pphm) O 3 (pphm) O 3 (pphm)
1 507 750 13.5 13.9 10.7 12.3 2b 254 598 11.5 12.1 9.4 10.7 3 250 530 11.6 12.0 9.4 10.7 4 309 523 12.4 12.2 9.8 11.1



### Sensitivity Simulations
A series of sensitivity analyses were conducte d using the August 19 97 episode to stress test the ozone modeling simulation. The analyses were conducted for the baseline emissions in 1997 and the two 2010 control opt ions. The goal of the sensitivity analyses is to test whether the simulation model is re sponding to gross changes in the emissions. A second objective is to determine the direct ion of the change in simulated ozone given the radical modification to the modeling syst em inputs or boundary conditions. Table 3- 16 lists the sensitivity runs conducted with the peak ozone predicted for the August 5, 1997 episode. What is depi cted in Table 3-18 is that the ozone simulation is most impacted by increasing biogenic emissions.



### CONCLUSIONS

The UAM simulations conducted for the A ugust 5-6 1997 and August 27-28, 1987 episode indicate that the Basin will attain the federal 1-hour ozone in the year 2010. The model formulation and base-year performance sa tisfies the criteria es tablished by EPA. Additional emissions controls will be require d to meet the federa l 8-hour average ozone standard once it is fully impl emented and a post 2010 attainment date has been set. Evaluation of ambient ozone data indicates that the CCAA requir ements for the per capita population exposure have been achieved in the Basin.Chapter 3 Revision to the 1997 Ozone Attainment Demonstration Plan

V-3- 97 Table 3-18
UAM Sensitivity Simulations: Pr edicted Maximum Ozone (ppb)

Description August 5 1997 1997 Base 182 Zero boundary condition 167 Zero initial condition 159 Zero emissions 39 Zero biogenics 156 Double biogenics 221 2010 2010 base 145 2010 base without stationary emissions 124 2010 base without mobile emissions 128 Biogenic plus 530 tons NOx 98 Option-1 controlled emissions with EPA boundary condition 121 Option-2 controlled emissions with EPA boundary condition 120 Option-1 with biogenics cut by 1/3 105 Option-2 with biogenics cut by 1/3 103 Option-1 with biogenics cut by 1/3 in 16 cells at Cleveland National Forrest 116

Option-2 with biogenics cut by 1/3 in 16 cells at Cleveland National Forrest 115

Option-1 with 2x biogenic emissions 146 Option-2 with 2x biogenic emissions 148 Option-1 with controlled emissions assuming 5 th is a Saturday and 6 th is a Sunday. 125

Option-2 with controlled emissions assuming 5 th is a Saturday and 6 th is a Sunday. 118

## CHAPTER 4 REVISION TO THE FEDERAL CARBON MONOXIDE ATTAINMENT DEMONSTRATION PLAN

Introduction

Carbon Monoxide Emissions Modeling Methodology Carbon Monoxide Control Strategy Future Air Quality Projections
ConclusionChapter 4 Revision to the Federal Carbon Monoxide Attainment Demonstration Plan

V-4-1 

### INTRODUCTION
The South Coast Air Basin (Basin) has hist orically had a persistent carbon monoxide (CO) problem. However, there has been cons iderable improvement in CO air quality in the Basin from 1976 to 2002. In 1976, the federal and state 1-hour average (35 ppm and 20 ppm) and 8-hour average (9.5 ppm and 9.0 ppm) carbon monoxide standards were exceeded in the Basin. In 1977 the federal 1-hour standard was met for the first time in the Basin, however the federal 8-hour standard continued to be exceeded over 100 days. With the turnover of older ve hicles, introduction of cleaner fuels and implementation of control technology on industrial facilities, CO c oncentrations in the Basin have steadily declined. In 1990 CO concentr ations exceeded the federal and state standards at 10 of 24 monitoring stations. In 1995, only 4 of 20 monitoring sta tions in the Basin exceeded the respective standards. Also in 1995, th e state 1-hour CO standard (20 ppm) was met for the first time. By 2000, the federal 8- hour standard was exceeded at only 3 of 26 monitoring stations in the Basin and on only tw o days. (A full descri ption of current CO air quality is contained in Appendix II of the 2003 AQMP)
In November 1990, Congress enacted a series of amendments to the Clean Air Act intended to intensify the air pollution contro l effort across the na tion. One of the primary goals of the 1990 Clean Air Act (CAA) was an overhaul of the planning provisions for those areas not currently meeting the National Ambient Air Quality Standards (NAAQS). The CAA identifies sp ecific emission reduction goals, requires demonstration of reasonable fu rther progress, and incorporat es more stringent sanctions for failure to attain or to meet interim m ilestones. Under the CAA, the South Coast Air Basin is designated as a serious nonattainme nt area for carbon monoxi de and is required to implement emissions reduction measures as “expeditiously as practicable” in order to attain federal carbon monoxide standards.

A Federal Attainment Plan for Carbon Monoxide (CO Plan) was approved by the District Governing Board on November 12, 1992 and submitte d to the U.S. Environmental Protection Agency (EPA). Th e CO Plan was designed to demonstrate the attainment of the NAAQS by 2000. The Plan was revised in the 1994 and 1997 Air Quality Management Plans (AQMP) to incorporate updated VMT and emissions projections and a revised control strategy. The 1997 AQMP was approved by the District Governing Board on November 15, 1996.
In 2001, the Basin met both the federal and st ate 8-hour CO standards for the first time at all monitoring stations. The Basin peak 8-hour average concentration of 7.7 ppm was measured at the Lynwood air monitoring st ation. However, during a particularly stagnant morning, (January 8, 2002), the CO 8-hour standard was exceeded at Lynwood. The highest 8-hour average CO concentra tion measured at L ynwood reached 10.7 ppm, approximately 113 percent of the federal sta ndard of 9.5 ppm. The 1-hour average peakFinal 2003 AQMP Appendix V: Modeling and Attainment Demonstrations

V-4-2 CO concentration at Lynwood was measured at 16 ppm,. While the 8-hour federal standard was exceeded at Lynwood on January 8 th , it proved to be th e only location and day in 2002 with 8-hour average CO concen trations recorded above 9.5 ppm. The provisions specified in CAA defining attain ment of the federal 8-hour average CO standard allows for no more than one day a nd location to exceed 9.5 ppm in a two year period. In accordance with th e CAA, the Basin is curren tly in compliance with the federal 8-hour standard.
The 2003 revision to the CO Plan provide s a duel purpose: it replaces the 1997 attainment demonstration that lapsed at th e end of 2000, and provides the basis for a CO maintenance plan for the future. Although trend of reducing fu ture carbon monoxide emissions is expected to continue, the 2003 AQMP does not include a request for EPA to consider re-designation of the Basin’s CO attainment status at this time.

The 2003 CO Plan revision reflects several updates to the 1997 CO Plan. The plan incorporates new forecasts of VMT, upda ted emissions factors from ARB’s on-road EMFAC2002 program (ARB, 2002), and revisions to the Direct Travel Impact Model (DTIM4). The “hot-spot” modeling methodol ogy remains the same as in the 1997 CO Plan. The 2003 CO plan uses the CAMx regional air quality model to take advantage of the more state of science a dvection, and dispersion scheme s and layer structure. In addition, a new CO episode, October 31-N ovember 1, 1997 replac es the 1989 episode used in the previous plans. The of the new episode satisfies with EPA’s policy to examine episodes that are less than 10-years old and are consistent with the ongoing air quality trend. An additional be nefit of the new episode is to make use of the enhanced meteorological and air monitoring that t ook place during the SCOS97 air monitoring program. A detailed discussion on the m odeling methodology and CO episode follows.



### CARBON MONOXIDE EMISSIONS

Introduction
In order to propose effective c ontrol measures, it is first necessary to identify the sources of pollution and to quantify th e type and amount of emissions they contribute. This chapter summarizes the updated carbon monoxide emissions inve ntory for the Basin. A more detailed description of inventory requirement s and procedures ca n be found in the 2003 AQMP, Appendix III.Chapter 4 Revision to the Federal Carbon Monoxide Attainment Demonstration Plan

V-4-3 

### Planning Inventory
The planning emissions inventor y is developed based on the winter period (defined as November through April) in which ambient concentrations of ca rbon monoxide in the Basin are highest.

The 1992 CO Plan was based on the 1990 carbon monoxide emission inventory submitted to U.S. EPA by the California Air Resources Boar d (ARB) in May 1992. This inventory was developed ba sed on U.S. EPA guidance (E PA, 1991). The ARB also submitted 1989 and 2000 mode ling emissions inventories in May 1992, which were used in the 1992 CO Plan attainment demons tration. The 1992 CO Plan used the EMFAC7EP emission factor program and vehi cle miles traveled (VMT) estimates and projections from the 1991 AQMP. The District committed to revising the CO Plan when updated emission factors and VMT forecasts became available. The 1994 Revision to the CO Plan uses emissions factors ge nerated by the ARB EMFAC7F program and VMT forecasts prepared by the Southern California Association of Governments (SCAG) for the 1994 AQMP. Again, th e 1997 CO plan used SCAG’s updated VMT forecast and ARB’s EMFAC7G on-road emi ssions factor progr am. The 2003 AQMP, including the 2003 CO Plan revision, uses the latest VMT forecast provided by SCAG and ARB’s current on-road emissions factor program EMFAC2002.

VMT Forecast
SCAG is responsible for preparing the VM T forecasts, estimating actual VMT, and annual reporting. The emission forecasts for all future years reflect demographic and economic growth forecasts by SCAG. Sec tion 187(a)(2)(A) of the CAA requires carbon monoxide nonattainment areas to forecast VMT for each year prior to the attainment year. The first set of forecasts was genera ted with the SIP revision (November 15, 1992) and included forecasts for all subsequent years up to the year of atta inment. The revised VMT forecast for the 2003 AQMP is presente d in Table 4-1 for 1997 through 2006. The VMT forecasts for 1997, 2002 and 2006 were provided by SCAG. Estimated VMT for the interim years were inte rpolated. DTIM4 was used to distribute growth among the different vehicle categories for all years with the exceptions of 2001, and 2004 which were interpolated.
The VMT forecast is provided beyond the or iginal 2000 attainment date. The VMT forecast includes the 1997 base-year, the 2000 original attainment date, the 2002 extended attainment date for the Basin (had the 2-year extension for the CO attainment demonstration been applied for and granted) and 2006 the milestone year for attaining the federal PM 10 standard. The VMT forecast for 2003 through 2006 is provided to support a weight of evidence demonstration that future year CO emissions will continue to lower, thus minimizing the likelihood that the CO 8-hour standard will be exceeded.Final 2003 AQMP Appendix V: Modeling and Attainment Demonstrations

V-4-4 TABLE 4-1 Daily Vehicle Miles Traveled (VMT) Forecasts (x 100,000 miles) from 1997 through 2006for the South Coast Air Basin

Year LightDuty Passenger Cars LightDuty Trucks MediumDuty Trucks HeavyDuty Trucks Urban and School

Bus Motorcycles

andMotorhomes All Vehicles

1997 1819 838 192 193 13 19 3074

1998 1814 867 196 195 14 18 3104

1999 1824 894 203 199 14 19 3153

2000 1844 905 205 202 15 19 3190

2001 1864 915 207 208 15 20 3228

2002 1883 925 209 214 15 20 3266

2003 1904 933 211 220 16 21 3304

2004 1937 946 214 231 16 22 3314

2005 1970 959 216 241 16 22 3324

2006 1970 957 214 247 16 23 3427

Emissions Projection
The future year baseline emissions are pr ojected from the 1997 em ission inventory and include emission reductions fro m rules and regulations adopt ed as of September 30, 2002. On-road mobile source carbon monoxi de emissions have increased about 21 percent in the 1997 base year relative to th e earlier submittals due to refinements in VMT and emissions factors. Table 4-2 pres ents the on-road vehi cle emissions for 1997 out to 2006. .Chapter 4 Revision to the Federal Carbon Monoxide Attainment Demonstration Plan

V-4-5 TABLE 4-2 Carbon Monoxide Emissions (tons/day) Pr ojected from 1997 through 2006 for the South Coast Air Basin

Year Light-Duty Passenger Cars LightDuty Trucks Medium -Duty Trucks HeavyDuty Trucks Urban and School Buses Motorcycles and

Motor - homes All Vehicles

1997 2453 1522 363 540 37 112 5027

2000 2056 1288 313 362 35 98 4152

2002 1673 1042 253 308 32 94 3402

2003 1519 953 234 288 31 93 3118

2005 1278 815 204 254 29 88 2668

2006 1172 761 194 240 28 85 2480

Planning Emissions Inventory
Table 4-3 shows a summary of the car bon monoxide planning emissions by major source category for the years 1997 and 2002. In 1997, on-road mobile sources contribute nearly 78 percent of the total emi ssions. Other mobile sources and stationary sources contributed 18 percen t and 4 percent, respectivel y, of the carbon monoxide emissions in the year 1997. The relative contribution of on-road mobile sources decreases to 70 percent in th e year 2002 to, as adopted re gulations and vehicle fleet turnover reduce emissions despite the incr ease in VMT. On-road mobile source contributions in 2006 are expected to be reduced an additional 27 percent over the 2002 to 2,480 tons per day.
Section 187(d)(1) of the Clea n Air Act requires a milestone demonstration by March 31, 1996 to determine whether the CO emissi ons reductions require d by December 31, 1995 have been achieved. The District provide d a 1995 CO emission inventory to the U.S. EPA by the required deadline.Final 2003 AQMP Appendix V: Modeling and Attainment Demonstrations

V-4-6 TABLE 4-3 Carbon Monoxide Emissions By Major S ource Category for the Years 1997 and 2002 Carbon Monoxide Planning Inventories (tons/day)

Source Category 1997 2002

Stationary Sources

Fuel Combustion 38 41
Waste Disposal 1 1

Petroleum Production
& Marketing 5 5

Industrial Processes 4 5

Miscellaneous Processes 203 315
(Including Waste Burning)
Total Stationary Sources 251 367

Mobile Sources

On-Road Vehicles 5027 3402

Other Mobile 1182 1065

Total Mobile Sources 6209 4467

Total 6460 4835



### MODELING METHODOLOGY

Introduction
U.S. EPA guidance requires that the modeli ng analysis include both areawide and hotspot modeling. An areawide analysis is performed to determine regional CO concentrations by applying a regional air quality simulation mode l. A “hot-spot” analysis provides CO concentrations at speci fied heavily traveled intersections. TheChapter 4 Revision to the Federal Carbon Monoxide Attainment Demonstration Plan

V-4-7 2003 revision to the CO Plan uses Comprehensive Air Qua lity Model with Extensions (CAMx) air quality simulation model to assess regional CO concentrations and CAL3QHC to perform the hot-spot analys is. This chapter describes the carbon monoxide (CO) modeling approach used to demonstrate attain ment of the federal 8-hour CO standard of 9.5 ppm. The 1992 CO Plan and 1994 AQMP provide additional supporting documentation describi ng the modeling procedures.



### Regional Modeling Analysis
The October 31-November 1, 1997 meteorol ogical episode resulted in the Basin’s highest measured 8-hour average carbon m onoxide concentration (17 ppm) since 1996. The peak concentration was measured at th e Lynwood, the air monitoring station that has historically measured the Basin’s hi ghest CO concentrations and the greatest frequency of days exceeding the federal st andard. The two-day episode took place during mid-fall on a Friday night and Saturday morning under very stagnant conditions. The episode took place on the weekend following the reversion to standard time. The following sections describe the meteorological and air quality characteristics of the October 31-November 1, 1997 August 1997 episode, the input preparation procedures used to develop the model input file for CAMx, and the respective model performance.



### Episode Selection
For the 2003 revision to the CO Plan, the October 31-November 1, 1997 carbon monoxide meteorological episode replaces the December 1989 episode. The episode was selected for three principal reasons. Fi rst, the episode is more recent that the December 1989 episode that occurred over ten year ago. EPA’s guidance for regional modeling recommends the use of meteorological episodes for air quality attainment demonstrations that are less than ten years ol d to ensure consistency in the trends of emissions. The 1997 episode occurred af ter the 1996 California Phase II fuel reformulation program in a period where the fuel is consistent with that used in 2002, the year selected for this attainment demonstr ation. Second, the Oc tober 31-November 1, 1997 episode measured the second highe st 8-hour average carbon monoxide concentrations in the Basin since fuel refo rmulation was implemented. (On January 12, 1996, a 17.3 ppm 8-hour average CO concentra tion was measured at Lynwood). Third, episode took place during the SCOS97 monitoring program, w ith its enhanced network of surface and upper air meteorological m onitoring. The SCOS97 monitoring was designed specifically to provide the data re quirement for sate-of-the-art regional air quality models.
Basin carbon monoxide episodes typically o ccur during the months of December and January during long cold nights that enhance nocturnal invers ions creating a very stableFinal 2003 AQMP Appendix V: Modeling and Attainment Demonstrations

V-4-8 environment. The episodes fall into two categories: a one-d ay morning peak that builds in the early morning hours a nd is enhanced by morning rush hour emissions. The second type of episode span s two days, commencing at the evening rush hour and building through the night into the following morning. The peak concentrations are often measured around midnight , gradually falling through the early morning hours on the second day. The severity of the episode is defined as the combination of local emissions being enhanced by the regional re-circulati on of urban, carbon monoxide emissions from the Central Los Angeles metropo litan area back to the South Central Los Angeles area. The December 1989 episode, an alyzed in the 1994 and 1997 CO Plan is characteristic of the 2-day ep isode. The October 31-November 1, 1997 episode is also in this category.
A statistical model was developed to better characterize the October 31-November 1, 1997 episode relative to the se ven year post fuel reformul ation period. Multi-variate regression was conducted us ing 8-hour average concen trations of Lynwood carbon monoxide and surface and uppe r air meteorological data for 1996. The equation developed from the analysis was applied to the meteorological data for the seven-year period to predict Lynwood carbon monoxide a nd establish a daily ranking. The log linear regression included surface pressure gr adient data (wind forcing), the vertical temperature structure of the near surface boundary layer and the number of hours of daylight. The October 31-November 1, 1997 episode ranked in the 94 th percentile of the distribution (2557 cases). However when the number of hours in the day were normalized for all days to reflect the Oc tober 31-November 1, 1997 period the ranking reaches the 98 th percentile and is equivalent to th at of January 12, 1996 when the peak carbon monoxide concentration wa s observed for the seven year period. For reference, January 8, 2002, the last day that 8-hour average carbon monoxi de concentrations exceeded the standard ranked in the 95 th percentile of the distribution.
The meteorological profile characterizing the top ranked carbon monoxide days is provided in Table 4-4. In general, high carbon monoxide concentrations occur when summer strength high pressure aloft envelops the Basin coupled with offshore pressure gradients that stagnate local winds. The uppe r level high acts to enhance the nocturnal radiation inversion, effectively restricting ai r flow to a shallow layer near the ground. The offshore tendency in the pressure gradients act to stagnate the see breeze early in the afternoon and direct the regional drift of urban carbon monoxide s outh from Central Los Angeles.



### Episode Characterization
The meteorological setting characterizing th e October 31-November 1, 1997 episode has been characterized as a part of the SCOS97 monitoring program. The episode has been documented in a special edition of Atmo spheric Environment through a specialChapter 4 Revision to the Federal Carbon Monoxide Attainment Demonstration Plan

V-4-9 secession of the AWMA Annual Conference, held in San Diego, June 1999. The following subsections examine the observe d synoptic and mesoscale meteorological profiles as well as the carbon monoxide air quality that was measure during the October 31-November 1, 1997 episode.

Table 4-4
Meteorological Profile of High Carbon Monoxide Episodes

Variable Value Std. Dev Units Time
VBG 500 Mb Pressure Surface Height 5823 54 M 0400 PST

Summation Surface Pressure Gradient
[LGB-DAG+RIV-DAG+SAN-LAS] -18.9 4.9 Mb 0700 PST

LAX-SFO Surface Pressure Gradient -4.5 2.1 Mb 0700 PST
950 Mb Temperature 17.8 3.0 o C 0400 PST
Inversion Top Temperature 18.7 3.7 o C 0400 PST
Inversion Strength 7.4 2.9 o C 0400 PST

Synoptic Setting
A strong ridge of high pressure aloft devel oped over the west coas t of California during the last week in October, 1997 and remained in place into the firs t week of November 1997. The ridge strengthened significantly between the morning (0400 PST)of October 30 th and the same time on the 31 st with the height of the 500 mb level increasing approximately 70 m in a 24 hour period. The center of th e high measure 5930 m located over the Southern California bight, positioned to bring the maximum level of subsidence to the Basin, enhancing the nocturnal inve rsion. (The 5920 m height at the 500 Mb pressure surface measured at Vandenburg Air Force Base is two st andard deviations above the average defining the high carbon monoxide episodes). Figure 4-1 illustrates the upper level pattern obser ved on October 31, 1997.
Mesoscale Setting
The mesoscale setting for the October31-N ovember 1, 1997 episode was dominated by developing offshore pressure gradients charac terized by high pressure building into the Great Basin and a local thermal trough off the San Diego Coast. Figure 4-2 depicts theFinal 2003 AQMP Appendix V: Modeling and Attainment Demonstrations

V-4-10 2200 PST surface pressure analysis for Oct ober 31, 1997. The orientation of the pressure gradient was from north to south with summation pressure gradients increasing offshore from –5.9 Mb at 0700 PST on the 31 st to –14.2 Mb at 0700 PST on the 1 st . The net result of the increasing offshore gradient s was to stagnate winds in the coastal portion of the Basin in the early evening. Velocities at most of the stations registered calm or 1-2 mph. Only a weak northeast to southwest gradient flow was observed throughout the night generating a mass drift fro m Central LA and th e south San Gabriel Valley back towards Lynwood following th e Los Angeles and San Gabriel River valleys. (The Los Angeles a nd San Gabriel River valleys ar e typically identified by the river channels and are bordered by a moderate el evation gain in the te rrain to the west of the City of Lynwood).

Figure 4-1
500 Mb Pressure surface contour pattern s on Friday October 31, 1997 at 0400 PST

The nocturnal inversion that developed over the Basin was greatly enhanced by the subsidence from aloft. The temperature measur ed at the at 950 Mb level from the San Diego sounding at 0400 PST on November 1 st reached 26.8 o C while the inversion top temperature reached 28 o C. . The inversion strength calculated for coastal Southern California was 11.9

o C. In all, the vertical temperature struct ure was at a minimum of one to two standard deviations more stagnant than the typical carbon monoxide episode.Chapter 4 Revision to the Federal Carbon Monoxide Attainment Demonstration Plan

V-4-11 Figure 4-2
Surface Pressure Analysis on Fr iday October 31, 1997 at 2200 PST

Air Quality Setting
The air quality profile that emerged duri ng the October 31-Nove mber 1, 1997 episode followed the meteorological setting for local stagnation being enha nce by regional drift of carbon monoxide from the Central L.A. (downtown) area. Carbon monoxide concentrations were background during the afte rnoon hours of October 31 st but began to rise as the sunset and the Friday traffi c phased into rush hour. Hourly averaged concentrations climbed to approximately 9 ppm throughout the coas tal plain by midnight on October 31 st with carbon monoxide leve ls reaching a peak 1-hour level of 19 ppm at Lynwood. The rise (approximately 4 ppm per hour) in CO at Lynwood occurred through local emissions from the surrounding fre eways and major arterial and from the emissions that drain through the coastal plain.
By midnight, concentrations of carbon monoxide began to fall at Central LA, Pico Rivera West L.A. and the San Fernando Valle y air monitoring stations. Concentrations at Lynwood held steady for three hours wh ile carbon monoxide at Hawthorne rose through 0600 PST on November 1 st . The maximum 8- hour average at Lynwood reached 17.0 ppm at 0400 PST on November 1 st and Hawthorne re ached 10 ppm at 0700 PST.Final 2003 AQMP Appendix V: Modeling and Attainment Demonstrations

V-4-12 

### Model Selection
CAMx was selected for the regional modeling demonstration. CAMx is a state-of-theart regional photochemical model that uses mu ltiple terrain following layers with fixed thickness, and the Bott advection solver for mass transport. The CAMx carbon monoxide simulations were run with the Carbon Bond IV (CB-IV) chemistry module using full chemistry. The MM5 prognostic and CALMET meteorological models were used to generate objective/di agnostic wind and mixi ng fields for the analysis. Estimates of horizontal and vertical diffusivity we re generated from the CALMET meteorological fields as input to the modeling simulation. The simulations we re run on the SCOS97 modeling domain (see Figure 4-3) using a five kilometer squared grid.

Meteorological Modeling and Input Fields
Meteorological modeling was pe rformed by coupling the meteor ological fields generated from the MM5 prognostic model with objectiv e data and diagnostic options of the CALMET meteorological model. The output of the MM5 prognostic meteorological model was used as a “first guess” wind assumption for the CALMET simulation. Observational data used to drive the si mulation was acquired from the SCOS97 fieldmonitoring program. CALMET was run using 17 vertical layers with the lowest layer consisting of 20 m in depth. Wind and temperature data were mapped to CAMX using layer interpolation.
Hourly upper air temperature a nd wind data measured at tw elve radar wind profiler and radio acoustic sounding systems (RWP/RASS) augmented the twice daily routine rawindsonde profiles measured at Vandenburg Air Force Base and Miramar Naval Air Station. The RWP/RASS measure winds to three kilometers above ground level (AGL) at approximately 150 m range gates. Temperature profiles routinely reached one kilometer AGL at the same measurement levels.
Surface wind, temperature and humidity and cloud cover data from 238 monitoring sites comprised the basis of the surface meteorol ogical fields. The data incorporated measurements from several monitoring networ ks including the District, Ventura County APCD, San Diego County APCD , California Irrigation Management System (CIMIS), FAA's METAR, Remote Automatic Weather System (RAWS), National Parks Networks (NPS) and Bureau of Land Management (BLM) networks. Figure 4-3 shows the location of surface meteorological stations.Chapter 4 Revision to the Federal Carbon Monoxide Attainment Demonstration Plan

V-4-13 150 250 350 450 550 650 UTM Easting 3600 3700 3800 3900UTM Northing

Figure 4-3
Surface Meteorological Stations

Mixing height fields were calculated dir ectly from the CALMET an alysis of the surface and vertical meteorological data. The mini mum mixing height was set to 50 m. and the minimum diffusivity coeffi cient was set to 0.1 cm 2 /sec. The vertical and horizontal dispersion coefficients (diffusivity) were calculated using an algorithm that employs formulas proposed by Holtslag and Ni euwstadt (1986), Wyngaard (1985, 1988), Businger (1982), and Tennekes (1982). The al gorithm calculates various parameters such as local momentum flux, friction velo city, local sensible heat flux, and MoninObukhov Length. The atmospheric layer is divided into regions according to the combination of the mixing depth, el evation above the ground and Monin-Obukhov Length. The diffusivity formul ation is grid based and the minimum vertical diffusivity coefficient was set to 0.1 cm 2 /sec.Final 2003 AQMP Appendix V: Modeling and Attainment Demonstrations

V-4-14 Trajectory Analysis
Figures 4-4 through 4-7 depict the time series (3-hour intervals, beginning at 1500 PST) of carbon monoxide transport simulated using the MM5/CALMET wind fields. The trajectory illustrates the transport of carbon m onoxide emissions injected into the Central L.A. grid and it movement during the early evening-late night hours of October 31 st

. The simulation illustrates the ability of the wind field to characterize the regional drift of carbon monoxide that contributed to background concentrati ons at Lynwood that night and the following morning.
CAMx Initial and Boundary Conditions
Initial conditions used by the CAMx simula tion were derived from hourly observational data measured by the District and neighboring air quality ag encies. The lateral boundary and top boundaries were set at “EPA Clean” North Amer ican continental average concentrations. Table 4-5 summarizes the species concentrations.

Base Year Emissions
The 1997 base year emissions inventory totaled 6425 tons of carbon monoxide per day. The total is approximately 35 tons lower that the 1997 tonnage listed in the planning inventory. The modeli ng inventory reflects day specific ambient temperature corrections made to mobile and other source operating conditions.
Day-of-Week Diurnal Traffic Patterns
One additional import segment of data ac quired as part of the SCOS97 monitoring program was the hourly vehicle count data m onitored in Basin by the 11 Caltrans weighin-motion (WIM) stations. The hourly vehi cle count profiles were day and location specific. The profiles were collected over during the course of the SCOS97 program and were aggregated into typical day-of-week pa tterns. The day pattern stratifies vehicle counts by hour and provides an im proved characterization of the diurnal traffic patterns. The data is expressed as an hourly frequency of the total daily vehicle use (e.g. hour 0-1 2 percent of the total traffic volume fro th e 24-hour period). The vehicle count data illustrates the different traffic patterns obser ved on weekdays (Thursday is used as a surrogate), Friday and Saturday. Figure 4-8 illustrates the Thursday, Friday and Saturday patterns for vehicle use by hour of day. This data was used to refine the traffic patterns defined by the DTIM4 transportation model.Chapter 4 Revision to the Federal Carbon Monoxide Attainment Demonstration Plan

V-4-15 Figure 4-4
Simulated Carbon Monoxide Tracer Release 1500 PST, October 31, 1997

Figure 4-5

Simulated Carbon Monoxide Tracer Release 1800 PST, October 31, 1997Final 2003 AQMP Appendix V: Modeling and Attainment Demonstrations

V-4-16 Figure 4-6
Simulated Carbon Monoxide Tracer Release 2100 PST, October 31, 1997

Figure 4-7

Simulated Carbon Monoxide Tracer Release 2300 PST, October 31, 1997Chapter 4 Revision to the Federal Carbon Monoxide Attainment Demonstration Plan

V-4-17 

# 0 2 4 6 8

1 4 7 10 13 16 19 22 Thurs Fri Sat % Hrs In Day

Figure 4-8
Diurnal Vehicle Usage Distribution from Ca ltrans Weigh-In-Motion Station Data

Base Year Model Performance
Table 4-6 shows the performance statistic s for the CAMx simulation using the 1997 baseline emissions inventory. Shown in Table 4-6 are the paired peak prediction accuracy (paired in space) and U.S. EP A-suggested two statistical performance measures. The accuracy of the peak 8-hour average prediction was - 12 percent and -24 percent for unpaired and paired peak prediction, respectively. The pa ired absolute error marginally exceeds the performance goal of 25 to 30 percent. The simulation is within the temporal absolute error of two hours.Final 2003 AQMP Appendix V: Modeling and Attainment Demonstrations

V-4-18 Table 4-5
EPA Clean Top and Lateral Boundary Concentrations

Species Concentration(ppm) NO 0.0010000 NO2 0.0020000 O3 0.0400000 OLE 0.0002760 PAR 0.0137000 TOL 0.0001640 XYL 0.0000900 FORM 0.0019280 ALD2 0.0005080 ETH 0.0004680 CRES 0.0000100 OPEN 0.0000100 PNA 0.0000100 NXOY 0.0000100 NO3 0.0000100 PAN 0.0000100 CO 0.2000000 HONO 0.0000100 H2O2 0.0000100 HNO3 0.0000100 SO2 0.0100000 SO4 0.0001000 AERO 3.0000000Chapter 4 Revision to the Federal Carbon Monoxide Attainment Demonstration Plan

V-4-19 TABLE 4-6 Performance Statistics for the October 31-November 1, 1997 CO Episode

Performance Measure CAMx U.S. EPASuggested Measures Peak 8-Hour Station Prediction 13.0 ppm -- Peak 8-Hour Regional Prediction 14.9 ppm -- Peak 8-Hour Measurement 17.0 ppm -- Paired Highest 8-Hour Prediction Accuracy -24% --

Unpaired Highest 8- Hour Prediction Accuracy -12 % +/- 30-35 %

Average Absolute Erro r in 8-Hour Peak Prediction 39 % 25-30 %

Average Absolute Erro r in the Predicted Time of the 8-Hour Peak Concentration for Station Pairs > 5.0 ppm 1.6 hours 2 hours

Figures 4-11 and 4-12 provide the temporal station model carbon monoxide performance for the coastal Basin stations for the 1-hour and 8-hour aver age concentrations respectively. The solid line depicts the predicted trend w ith observations depicted as squares. The CAMx simulation captures th e diurnal trend obser ved at Lynwood during the night of October 31 st and morning of November 1 st . The general tendency for the model is to under-predict regional carbon monoxide concen trations. However, this tendency is consistent with th e use of a 5 kilometer grid wh ere emissions and transported carbon monoxide is uniformly distributed throughout the grid.
Figures 4-13 through 4-16 present the CA Mx predicted carbon monoxide spatial distribution for 1500, 1800, 2100 and 2300 PST on October 31, 1997. As is depicted in the sequence, carbon monoxide builds from th e early evening, peaking over South Central Los Angeles near midnight. The ca rbon monoxide levels al so rise throughout the Basin and Ventura and San Diego in response to the stagnant conditions.Final 2003 AQMP Appendix V: Modeling and Attainment Demonstrations

V-4-20 Figure 4-11

CAMx Simulated vs. Observed 1-hour Av erage Carbon Monoxide for the October 31- November 1, 1997 Meteorological EpisodeChapter 4 Revision to the Federal Carbon Monoxide Attainment Demonstration Plan

V-4-21 Figure 4-12

CAMx Simulated vs. Observed 8-hour Av erage Carbon Monoxide for the October 31- November 1, 1997 Meteorological EpisodeFinal 2003 AQMP Appendix V: Modeling and Attainment Demonstrations

V-4-22 Figure 4-13 CAMx Simulated Regional Carbon Monoxide 1500 PST, October 31, 1997

Figure 4-14 CAMx Simulated Regional Carbon Monoxide 1800 PST, October 31, 1997Chapter 4 Revision to the Federal Carbon Monoxide Attainment Demonstration Plan

V-4-23 Figure 4-15 CAMx Simulated Regional Carbon Monoxide 2100 PST, October 31, 1997

Figure 4-16 CAMx Simulated Regional Carbon Monoxide 2300 PST, October 31, 1997Final 2003 AQMP Appendix V: Modeling and Attainment Demonstrations

V-4-24 

### Hot Spot Analysis
The hot-spot analysis was performed using CAL3QHC. CAL3QHC is a model developed to predict the leve l of CO or other inert pollutant concentration emitted from motor vehicles at roadway intersections. CAL3QHC inputs include roadway geometry, receptor locations, meteorological conditions and vehicular emissions rate. A general description of the selection of the hot spot intersection, model input assumptions, and model application was presented in the 1992 CO Plan and is not repeated here.
The CAL3QHC model was applied to the four intersections listed in Table 4-7 to estimate the CO impacts from motor vehicles traveling at roadway intersections. CO concentrations were estimated for both th e 1997 base year and fo r the year 2002 based on projected traffic volume and emission fa ctors. The Octobe r 31-November 1, 1997 episode specific meteorological conditions fo r the grid cell hosting the intersection was used for the simulation. Ta bles 4-8, 4-9, and 4-10 s how the model predicted and calculated CO concentration at the select ed intersection in the years 1997 and 2002.

TABLE 4-7 Selected Intersections for the CAL3QHC Hot Spot Modeling Analysis

Intersection Receptor Description
Long Beach Blvd. /Imperial Highway Lynwood Air Monitoring Station The Lynwood air monitoring stations consistently records the highest 8-hour CO concentrations in the Basin each year
Wilshire Blvd./ Veteran Ave. No Air Monitoring The most congested intersection in Los Angeles county. The average daily traffic volume is about 100,000 vehicles/day. Highland Ave./ Sunset Blvd. No Air Monitoring Station One of the most congested intersections in the city of Los Angeles. The intersection study has been conducted and traffic data is available. Century Blvd./ La Cienega Blvd. No Air Monitoring Station One of the most congested intersections in the city of Los Angeles. The intersection study has been conducted and traffic data is available.Chapter 4 Revision to the Federal Carbon Monoxide Attainment Demonstration Plan

V-4-25 TABLE 4 -8 Emissions Predicted by EM FAC2002 in Year 1997 and 2002

Wilshire - Veteran Sunset - Highland La Cienega - Century Long Beach - Imperial AM PM AM PM AM PM AM PM

a) EMFAC2002 Emission Variables (1997) Running Exhaust Emission Factor (g/mile) 11.57 11.96 13.31 12.72 11.82 11.66 11.92 11.93

Idling Emission Factor (g/min) 2.13 2.18 2.43 2.32 2.19 2.15 2.22. 2.18

b) EMFC2002 Emission Variables (2002) Running Exhaust Emission Factor (g/mile) 7.20 7.21 7.22 7.98 7.31 7.24 7.35 7.48

Idling Emission Factor (g/min) 1.24 1.24 1.25 1.30 1.27 1.25 1.28 1.28

TABLE 4-9 1997 1-Hour Average Carbon M onoxide Concentrations Calculated from the CAL3QHC Model

Morning * Afternoon + Peak ++

Wilshire -

Veteran 7.7 5.7 --

Sunset - Highland 6.9 7.3 -- La Cienega - Century 6.4 5.2 --

Long Beach - Imperial 5.1 5.2 2.2

* Morning : 7-8 a.m. for La Cienega - Century, 11-12 a.m. for Sunset - Highland, 8-9 for WilshireVeteran, and 7-8 a.m. fo r Long Beach - Imperial + Afternoon : 3-4 p.m. for Sunset - Highland, 3-4 p.m. for Wilshire - Veteran, 4-5 p.m. for Long Beach - Imperial, and 6-7 p.m. for La Cienega - Century ++ Peak : 11-12 p.m. (concentration at the hour of the observed peak). Peak is only provided for the Long Beach/Imperial intersection since it is inters ection associated with the regional peak at Lynwood.Final 2003 AQMP Appendix V: Modeling and Attainment Demonstrations

V-4-26 TABLE 4-10 Year 2002 1-Hour Average Car bon Monoxide Concentrations Calculated from the CAL3QHC Model

Morning * Afternoon + Peak ++

Wilshire-Veteran 4.6 3.5 -- Sunset-Highland 4.0 4.5 -- La Cienega-Century 3.7 3.1 -- Long Beach-Imperial 3.0 3.1 1.2

* Morning : 7-8 a.m. for, La Cienega - Century, 8-9 a.m. for Wilshire - Veteran, 7-8 a.m. for Long Beach - Imperial, and 8-9 a. m. for Sunset - Highland + Afternoon : 3-4 p.m. for Sunset - Highland, 5-6 p.m. for Wilshire - Veteran, 4-5 p.m. and Long Beach - Imperial, and. 6-7 p.m. for and La Cienega - Century ++ Peak : 11-12 p.m. (concentration at the hour of the observed peak) ). Peak is only provided for the Long Beach/Imperial intersection since it is intersection associat ed with the regional peak at Lynwood.



### CARBON MONOXIDE CONTROL STRATEGY
Mobile sources, which are regulated primarily by ARB or U.S. EPA, produce the largest amount of carbon monoxide emissions in the Ba sin. The on-road motor vehicle control strategy is primarily based on adopted regul ations, such as the 1990 ARB Low-Emission Vehicles and Clean Fuels (LEV/Clean Fu els) regulations, Phase 2 Reformulated Gasoline Program, oxygenated fuel regulation, and enhancemen ts to the Inspection and Maintenance (I/M) or Smog Check program . The emission reduction resulting from these already adopted regulations are sufficien t to demonstrate attainment in the year 2002, as discussed in a later section.



### Contingency Measures
Section 187(a)(3) of the 1990 CAAA requires th at adopted and enforceable contingency measures be included in the attainment plan submission. A deviation from the forecasted VMT of more than a given pe rcentage will trigger implementation of contingency measures to offset either ex cess VMT or carbon monoxi de emissions due to the additional VMT. Accord ing to the EPA General Preamble [Sect. 532(c)(1)], this percentage is 5 percent in 1994, 4 pe rcent in 1995, and 3 percent for 1996 and subsequent years. The cumulative VMT grow th cannot be greater than or equal to 5 percent above the VMT forecast used as th e basis of the attainment demonstration.Chapter 4 Revision to the Federal Carbon Monoxide Attainment Demonstration Plan

V-4-27 District Rule 1504 was adopted to serve as contingency for carbon monoxide. Table 4- 11 lists the control measures that will also serve as contingenc y measures for carbon monoxide. These measures are described fu rther in Appendix IV-A of the 1997 AQMP.

TABLE 4-11 Level I - Contingency Measures from the 1997 AQMP Which May Serve as Carbon Monoxide Contingency Measures

AQMP Measure Number Title Priority to Meet CAA Requirements Responsible Agency Issues

CTY-4 Enhanced Oxygenated Fuel Content for CO 1 ARB Potential NO x Emission Increases

CTY-1 Accelerated Implementation of Control Measures 2 District Resource Availability

CTY-2 Command and Control Rules in Place of Educational

Outreach Program Measures 3 District Resource Availability/ Cost Effectiveness



### FUTURE AIR QUALITY PROJECTIONS

Introduction
Air quality modeling is an integral part of the planning process to achieve clean air. Based on U.S. EPA’s modeling guidelines, CAMx is used for the areawide analysis, and CAL3QHC, a roadway intersection model, is used to calculate carbon monoxide concentrations near intersections. The CAMx model results are used to evaluate the effectiveness of control measures in attain ing the federal 8-hour air quality standard for carbon monoxide in the year 2002. U.S. EPA’ s modeling guidelines recommend that the results from CAL3QHC and CAMx be combined to give a total concentration that is used for attainment demonstration purposes. Ho wever, conclusions from a 1989 study, conducted by ARB and the District in the vicinity of the Lynwood area, indicate that the areawide and ‘hot-spot’ model results should not be comb ined. The study indicates that the CO measurements at the Lynwood monitoring station are representative of the entire Lynwood area. Based on the conclusions of the Lynw ood study, the areawide analysis and the “hot-Final 2003 AQMP Appendix V: Modeling and Attainment Demonstrations

V-4-28 spot” analysis results for the attainment dem onstration are not combined. A more detailed discussion of this subject can be found in the 1992 CO Plan.



### Emissions
The 2002 modeling emission inventory consists of area, point and mobile sources. More than 90 percent of CO emissions are from mob ile sources. Area source and point source CO emissions are only 9 percent of the total i nventory. The carbon monoxide modeling analysis for the Basin uses a grid level emission inve ntory representing day-specific mobile source emissions.
The 1997 and 2002 carbon monoxide emissions used in the CAMx modeling analysis are shown in Table 4-12. The emissions estimates include the emission reductions from all air quality rules and regulations adopted prior to September 30, 2002, including the effect of the enhanced I/M program and the oxygenated fuel re gulation. The emissions presented in this table reflect the revised VMT forecast from SC AG and the latest version of ARB’s on-road emission factor program, EMFAC2002.

TABLE 4-12 Baseline and Projected Future Basin Carbon Monoxide Emissions (tons/day)

Case On-Road Mobile Others Total

1997 5223 1202 6425
2002 3259 1116 4375



### Modeling Results
CAMx Regional Simulation
Table 4-13 presents the projec ted carbon monoxide concentra tions for the Basin and at the Lynwood station in the years 1997 a nd 2002. The predicted maximum 8-hour concentration of 14.9 ppm occurred in the L ynwood area at the same time (0400 PST) as the measured maximum 8-hour concentrati on of 17.0 ppm on Nove mber 1, 1997. The predicted maximum 8-hour concentration is within the model peak performance goal recommended by the U.S. EPA. The predicte d regional 1-hour averag e concentration is 16.7 whereas the observed va lue was 19 ppm. The maximum predicted 8-hour carbon monoxide concentration at the Lynwood station is 13.0 ppm.Chapter 4 Revision to the Federal Carbon Monoxide Attainment Demonstration Plan

V-4-29 TABLE 4-13 Peak Carbon Monoxide Concentrations ( ppm) Predicted by CAMx for the Basin

Scenario Regional Maximum (8-hour Average) Maximum Lynwood (8-hour Average) Regional Maximum (1-hour Average)

1997 Base 14.9 13.0 16.7
2002 Base 9.9 8.7 10.8
Note: Federal Standards: 9.5 ppm, 8-hour average; 35 ppm, 1-hour average
In the 2002 modeling analysis the pred icted regional maximum 8-hour average concentration is reduced by 34 percent from 1997 to 9.9 ppm. The 2002 predicted 8- hour average concentration at the Lynwood mon itor is reduced by 33 percent to 8.7 ppm. The regional maximum 1-hour average conc entration drops by 36 percent in 2002 to 10.8 ppm. The time of the peak 8-hour av erages (both regional and at Lynwood) remained at 0400 PST.

The carbon monoxide air quality projecti ons are based on CAMx and CAL3QHC simulations analyses for the fall meteorologi cal episode. The Oct ober 31-November 1, 1997 episode recorded maximum 1-hour and 8-hour average carbon monoxide concentrations of 19.0 ppm and 17.0 ppm, respectively. These were the highest recorded values in the Basin since 1996. The 2002 predicted 8-hour average maximum concentration closely matches the maximu m observed carbon monoxi de concentration measured at Lynwood in 2002 (10.1 ppm on January 8 th ). However, the concentration exceeds the federal and state levels by a marginal amount.

Linear Rollback of CAMx Simulation Results

Figure 4-17 depicts the tre nd of EMFAC2002 projected ca rbon monoxide emissions for 1997 through 2005. On-road CO emissions from vehicles that are the primary contributors to urban carbon m onoxide episodes are projected to decrease by an average of seven percent per year in 2003 through 2005. Total CO emissions reductions for all categories are projected to be reduced betw een 5 and 6 percent per year through 2005.
A linear rollback approach is used to ev aluate CO concentrations beyond 2002. It assumes that the ambient concentrations above background levels are directly proportional to the emissions in the immedi ately adjacent areas. With CO being essentially inert, this assump tion is reasonable. In math ematical terms, the rollback relationship can be written as follows:Final 2003 AQMP Appendix V: Modeling and Attainment Demonstrations

V-4-30 C p = [(C b - k) • Q p /Q b ] + k

where C p and C b are the future year and baseline CO concentrations, respectively; Q p and Q b are the future year and baseline CO emission rates, respectively; and k denotes the global background CO concentration. It is assumed that global background CO concentrations are negligible; theref ore the above equation simplifies to

C p = C b • Q p /Q b
For the 2003 AQMP CO attainment demonstration, linear roll back is used to extend the CAMx simulated regional maximum 8-hour average concentration beyond 2002 to predict carbon monoxide concentrations for 2003, 2004 and 2005. Using linear rollback, the CAMx 2002 base year simulation and the projected reduction in CO emissions, the predicted carbon monoxide maximu m 8-hour concentration is e xpected to be reduced to 9.1 ppm in 2003, 8.4 ppm in 2004 and 7.8 ppm in 2005. Th e continued reductions in carbon monoxide emissions are expected to main tain the attainment of the federal 8-hour standard demonstrated th rough observations in 2001 and 2002. The California 8-hour average carbon monoxide standard is projected to be met in 2004. The results are summarized in Table 4-14.

0 1000 2000 3000 4000 5000 6000

1997 1998 1999 2000 2001 2002 2003 2004 2005(TPD)

FIGURE 4-17 EMFAC2002 Projected On-Road Carbon Monoxide Emissions for 1997 Through 2005Chapter 4 Revision to the Federal Carbon Monoxide Attainment Demonstration Plan

V-4-31 TABLE 4-14

Carbon Monoxide Emissions and M odel-Predicted Concentrations
CO-Planning 8-hr Maximum 1-hr Maximum Year/Scenario Inventory Concentration Concentration (tons/day) (ppm) (ppm) 1997 Baseline 6460 14.9 16.7

2002 Baseline 4835 9.9 10.8

2003 Predicted 4527 9.1 9.9

2004 Predicted 4278 8.4 9.2
2005 Predicted 4029 7.8 8.5

State 1-hr CO standard = 20 ppm State 8-hr CO standard = 9.0 ppm Federal 8-hr CO standard = 9.5 ppm


### CAL3QHC Modeling Results and Combined “Hot Spot” and Areawide Maximum Analysis
The maximum CAL3QHC 8-hour average concentrations projected at the four roadway intersections (regardless of time of day) a nd the CAL3QHC 8-hour average concentrations projected for the hour coincident with the occurrence of the CAMx simulated area-wide maximum impact are presented in Table 4-15. Also presented are the CAMx projected areawide maximum concentrations for the grid ce ll hosting the intersection and the sum of the CAMx projected area-wide maximum and the CAL3QHC 8-hour average concentrations projected for that hour. Linear rollback is used to extend the CAL3QHC "hot spot" intersection and the CAMx area-wide grid cell simulations from 2002 through 2005. The CAL3QHC analysis was conducted using the actual meteorological conditions for the episode. It should be noted that the project ed maximum concentrations from the CAMx and CAL3QHC do not occur at the same time of the day and cannot be directly added. (The “hot spot” predicted carbon monoxide 8-hour aver age maximum concentrations at the intersections occurred between 1200 and 1400 PST).
Projected maximum “hot-spot” concentrati ons in the year 2002 are between 2.3 and 3.8 ppm. CAMx projected area-wide carbon monoxide peak 8-hour average concentrations (for the grid cell hosting the intersection) in the year 2002 are between 1.6 and 9.2 ppm. The highest CAMx simulated 8-hour carbon monoxide concentration occurs at Lynwood, the highest “hot-spot” concentration does not o ccur at Lynwood, but at intersections in Hollywood and Westwood. The maximum eight hour average “hot-spot” concentrationFinal 2003 AQMP Appendix V: Modeling and Attainment Demonstrations

V-4-32 predicted for the intersection of Imperial a nd Long Beach Blvd. at the time of the observed maximum (0600 PST) values 0.8 ppm.
Adding the 2002 Lynwood 0600 PST 8-hour average “ hot spot” intersection impact to the CAMx predicted 0600 PST 8-hour average for the grid cell hosting the Lynwood monitoring station results in a total impact of 10.0 ppm. This value is close to the 2002 observed maximum 8-hour average concentration (10.7 ppm) at Lynwood on January 8 th (meteorologically ranked 95 th percentile, or an expected frequency of occurrence on 15 days per year). The comparison provides a measure of confirmation in the modeling analyses and 2002 emissions estimates. Extending this analysis beyond 2002 using the projected 6.4 percent annual reduction in mobile sour ce carbon monoxide emissions between 2002 and 2003 demonstrates that Lynwood, and with it the Basin, will attain the federal CO standard in 2003. Additional 5.6 percent annual reduc tions in mobile source carbon monoxide emissions in each of the two following years ar e expected to minimize the likelihood for the carbon monoxide standard to be exceeded in the future.
As discussed in the 1992 CO Plan, peak carbon monoxide concentrations are due to unique meteorological and topographical conditions, a nd not due to the impact of particular intersections. This is based on the results of a 1991 Lynwood Carbon Monoxide Study prepared for the ARB. This is also confirmed by the minimal CAL3QHC predicted intersection impact (less than 1.0 ppm for 2002) during the early morning hours. It is inappropriate to combine the maximum area-wide analysis and the maximum “hot-spot” analysis results for Lynwood in the attainment demonstration because the timing of the simulated peaks are not aligned. However, wh en the timed intersection and area-wide grid cell peaks are combined, a more realistic a ssessment arises. This analysis, as does the regional simulation, demonstrates that the federal carbon monoxide standard will be attained in 2003. Furthermore, both analyses indicate that the California carbon monoxide standard will be attained in 2004.



### CONCLUSION
The Clean Air Act requires that an attainment de monstration be performed as part of a plan submittal. Ambient monitoring data for 2001 and 2002 have provided the basis for a future change of the Basin attainment status for the 8-hour NAAQS from severe non-attainment to attainment. This attainment demonstration ha s been conducted to serve as confirmation to the observed trend and to provide a foundation fo r the development of a future maintenance plan for the Basin. Per the U.S. EPA r ecommendation, a region-wide modeling analysis using a regional air quality simulation model-CA Mx and a hot-spot modeling analysis using CAL3QHC were performed. These analyses confirm through model predictions of the expected 2002 maximum 8-hour average carbon monoxide concentrations that the Basin’s projection to achieve the NAAQS by 2002 without additional control of CO is consistent with the observed trend. Furthermore, proj ected continued annual CO emission reductions will keep the Basin in attainment and further improve CO air quality to meet the California 8-hour average CO standard by 2004.Chapter 4 Revision to the Federal Carbon Monoxide Attainment Demonstration Plan

V-4-33 TABLE 4-15 Projected 8-hour Carbon Monoxide Concentrations (ppm) at Various Intersections Located in the South Coast Air Basin

Year Maximum Areawide Maximum "Hot Spot" Time of Maximum "Hot Spot" Time of Maximum Areawide "Hot Spot" at time of Maximum Areawide Maximum Areawide and "Hot Spot" at time of Maximum Areawide

Long Beach Blvd. and Imperi al Hwy. located in Lynwood

1997 14.5 4.2 1300 PST 0600 PST 1.5 16.0

2002 9.2 2.3 0.8 10.0

2003 8.6 2.2 0.7 9.3

2004 8.1 2.0 0.7 8.8

2005 7.7 1.9 0.7 8.4

Wilshire Blvd. and Veteran Ave. located in Westwood

1997 2.3 5.8 1400 PST 1100 PST 4.6 6.9

2002 1.6 3.4 2.9 4.5

2003 1.5 3.2 2.7 4.2

2004 1.4 3.0 2.6 4.0

2005 1.3 2.8 2.4 3.7

Sunset Blvd. and Highland Ave. located in Hollywood

1997 3.3 6.6 1400 PST 0300 PST 3.5 6.8

2002 2.1 3.8 2.0 4.1

2003 2.0 3.6 1.9 3.9

2004 1.9 3.4 1.8 3.7

2005 1.8 3.2 1.7 3.5

La Cienega Blvd. And Century Blvd. Located in Inglewood

1997 8.0 4.5 1200 PST 0800 PST 3.0 11.0

2002 4.5 2.6 1.7 6.2

2003 4.2 2.5 1.6 5.8

2004 4.0 2.3 1.5 5.5

2005 3.8 2.2 1.4 5.2

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