FINAL

VENTURA COUNTY

2007 

AIR QUALITY

MANAGEMENT PLAN

Adopted by the 

Ventura County Air Pollution Control Board 

May 13, 2008 

VENTURA COUNTY

AIR POLLUTION CONTROL DISTRICT

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MAY 2008 PAGE i 

TABLE OF CONTENTS 

LIST OF FIGURES..........................................................................................................v

LIST OF TABLES .........................................................................................................vii

LIST OF APPENDICES .................................................................................................ix

ACRONYMS ..................................................................................................................xi

EXECUTIVE SUMMARY ................................................................................................ 1

1. BACKGROUND......................................................................................................... 5

1.1. Purpose..............................................................................................................................6 

1.2. Federal 8-hour Ozone Attainment Status Reclassification...............................................6 

1.3. Federal Clean Air Act and Air Quality Standards ............................................................7 

1.3.1. Federal 1-hour Ozone Standard ........................................................................... 8 

1.3.2. Federal 8-hour Ozone Standard ........................................................................... 8 

1.4. California Clean Air Act and Air Quality Standards........................................................9 

1.4.1. California 1-hour Ozone Standard..................................................................... 10 

1.4.2. California 8-hour Ozone Standard..................................................................... 11 

1.5. Progress in Improving Ventura County Air Quality.......................................................11 

1.5.1. Reduction in Ozone Levels................................................................................ 11 

2. 2002 BASELINE EMISSIONS INVENTORY ........................................................... 15

2.1. Emissions Inventory Reporting Requirements ...............................................................15 

2.2. Emissions Inventory Major Categories...........................................................................16 

2.2.1. Stationary Sources ............................................................................................. 16 

2.2.2. Mobile Sources .................................................................................................. 18 

2.2.2.1. On-Road and Off-Road Emissions ..................................................... 18 

2.2.2.2. Other Mobile Sources ......................................................................... 18 

2.3. Ventura County Marine Emissions Inventory ................................................................21 

2.3.1. Ventura County Portion of the South Central Coast Air Basin ......................... 21 

2.3.2. Outer Continental Shelf Air Basin Marine Emissions....................................... 22 

3. CONTROL STRATEGY........................................................................................... 25

3.1. Stationary Source Control Measures ..............................................................................26 

3.1.1. Control Measures with Emission Reductions Beyond the Base Year............... 26 

3.1.2. New Stationary Source Control Measures......................................................... 26 

3.1.3. Further Study Control Measures........................................................................ 30 
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3.1.4. Reasonably Available Control Measures........................................................... 31 

3.1.5. Reasonably Available Control Technology....................................................... 31 

3.1.6. RACT SIP .......................................................................................................... 31 

3.1.6.1. Updated CTGs .................................................................................... 32 

3.1.7. New Source Review........................................................................................... 32 

3.1.8. Control Measures Not Retained in the 2007 AQMP ......................................... 33 

3.2. Transportation Control Measures ...................................................................................36 

3.2.1. Transportation Control Measures Categories and Projects ............................... 37 

3.2.2. TCM Rollover and Substitution......................................................................... 38 

3.2.3. Reasonably Available Control Measures - TCMs ............................................. 39 

3.2.4. Motor Vehicle Trips and VMT vs. On-Road Motor Vehicle 

Emissions ........................................................................................................... 39 

3.3. Conformity......................................................................................................................40 

3.3.1. Transportation Conformity ................................................................................ 41 

3.3.2. General Conformity ........................................................................................... 42 

3.4. Incentive Programs .........................................................................................................43 

3.4.1. Clean Air Fund................................................................................................... 43 

3.4.2. Moyer Memorial Air Quality Standards Attainment Program .......................... 43 

3.4.3. Lower-Emission School Bus Program............................................................... 44 

3.4.4. Electric Lawn Mower Trade-In Rebate Program .............................................. 45 

3.5. Ventura County Smart Growth Policies and Programs ..................................................46 

3.6. State Strategy ..................................................................................................................49 

4. EMISSIONS INVENTORY FORECAST .................................................................. 51

4.1. Forecast Methodology ....................................................................................................51

4.1.1. External Adjustments to CEFS v1.06 ................................................................ 54 

4.1.2. Emission Reduction Credits............................................................................... 56 

4.2. Emissions Forecast Summary.........................................................................................56 

4.3. Ventura County Marine-Related Emissions Forecast.....................................................64 

4.3.1. SCC Air Basin Marine-Related Emissions........................................................ 64 

4.3.2. OCS Air Basin Marine-Related Emissions........................................................ 65 

4.4. Naval Base Ventura County Emission Forecasts ...........................................................69 

5. FEDERAL 8-HOUR OZONE REASONABLE FURTHER PROGRESS .................. 71

5.1. Introduction.....................................................................................................................71 

5.2. RFP Demonstration.........................................................................................................72 

6. FEDERAL 8-HOUR OZONE MODELING AND ATTAINMENT 

DEMONSTRATION ................................................................................................. 75
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6.1. Introduction.....................................................................................................................75 

6.2. Photochemical Modeling and Weight of Evidence Analyses.........................................75 

6.3. Attainment Demonstration..............................................................................................75 

7. CONTINGENCY MEASURES ................................................................................. 77

7.1. Introduction.....................................................................................................................77 

7.2. Reasonable Further Progress and Attainment Contingency Measures...........................78 

7.2.1. RFP Contingency Measures............................................................................... 78 

7.2.2. Attainment Contingency Measures.................................................................... 78 

8. CALIFORNIA OZONE TRIENNIAL ASSESSMENT AND PLAN UPDATE ............ 79

8.1. Triennial Assessment and Plan Update Requirements ...................................................79 

8.2. Air Quality Indicators .....................................................................................................80 

8.2.1. Population-Weighted Exposure & Area-Weighted Exposure ........................... 80 

8.2.2. Expected Peak Day Concentration .................................................................... 82 

8.3. Emissions Trends............................................................................................................83 

8.4. Overall Progress..............................................................................................................83 

8.5. AQMP Control Measure and Rulemaking Update .........................................................84 

8.5.1. Control Strategy Cost Effectiveness .................................................................. 84 

8.5.2. Control Measures Amended or Implemented 2003 – 2005 & Control 

Measures Still Reducing Emissions Beyond the 2002 Emission 

Inventory Base Year .......................................................................................... 84 

8.5.3. Status of Control Measures Scheduled for Revision 2003 – 2005 .................... 85 

8.6. Every Feasible Measure..................................................................................................87

8.7. Control Measures Deleted from the 2007 AQMP ..........................................................90 

8.8. Ozone Transport .............................................................................................................90 

8.9. Public Information ..........................................................................................................90 

9. EMERGING ISSUES ............................................................................................... 93

9.1. New Federal 8-hour Ozone Standard..............................................................................93 

9.2. Climate Change...............................................................................................................93 

9.2.1. Climate Change Initiatives................................................................................. 94 

9.2.2. United Nations Framework Convention on Climate Change ............................ 95 

9.2.3. United States Climate Change Policy and Initiatives ........................................ 95 

9.2.4. California Climate Change Initiatives ............................................................... 95 

GLOSSARY .................................................................................................................. 97
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LIST OF FIGURES 

Figure 1-1 Countywide Days Over Federal & State Ozone Standards vs. 

Population Growth ...................................................................................................12 

Figure 1-2 Countywide 8-Hour Ozone Values ..........................................................................13 

Figure 1-3 8-Hour Ozone Values for Simi Valley & Ojai Valley .............................................13 

Figure 1-4 8-Hour Ozone Values for Piru & Thousand Oaks ...................................................14 

Figure 1-5 8-Hour Ozone Values for Casitas Pass, Ventura, & El Rio .....................................14 

Figure 2-1 2002 Baseline Summer Planning Day Emissions Pollutant Distribution ...............17 

Figure 2-2 Ventura County 2002 Planning Day ROG Emissions Inventory.............................20 

Figure 2-3 Ventura County 2002 Planning Day NOx Emissions Inventory..............................20 

Figure 2-4 Ventura County 2002 Planning Day ROG Emissions Inventory 

(OCS Air Basin) .......................................................................................................24 

Figure 2-5 Ventura County 2002 Planning Day NOx Emissions Inventory 

(OCS Air Basin) .......................................................................................................24 

Figure 3-1 Trips and VMT vs. On-Road Motor Vehicle Emissions Trends..............................40 

Figure 4-1 ROG Major Source Category Trends.......................................................................59 

Figure 4-2 NOx Major Source Category Trends .......................................................................60 

Figure 4-3 Ventura County 2012 Planning Day ROG Emissions Inventory.............................63 

Figure 4-4 Ventura County 2012 Planning Day NOx Emissions Inventory..............................63 

Figure 4-5 Ventura County 2012 Planning Day ROG Emissions Inventory 

(OCS Air Basin) .......................................................................................................68 

Figure 4-6 Ventura County 2012 Planning Day NOx Emissions Inventory 

(OCS Air Basin) .......................................................................................................68 

Figure 8-1 Population & Area-Weighted Exposure...................................................................81 

Figure 8-2 Percent Reduction in Expected Peak Day Ozone Concentrations: 

1986 – 2005..............................................................................................................83 
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LIST OF TABLES 

Table 2-1 2002 Baseline Summer Planning Day Emissions ....................................................16 

Table 2-2 2002 Baseline Planning Emissions by Major Source Category...............................19 

Table 2-3 2002 OCS Baseline Planning Emissions by Emissions Inventory 

Category Name.........................................................................................................23 

Table 3-1 Stationary Source Control Measures - Local Control Measures Only.....................27 

Table 3-2 New Stationary Source Control Measures ...............................................................27 

Table 3-3 Further Study Control Measures ..............................................................................31 

Table 3-4 Control Measures Not Retained in the 2007 AQMP................................................34 

Table 3-5 TCM Project Categories Included in R-700/N-700 .................................................38 

Table 3-6 Motor Vehicle Emissions Budget ............................................................................42 

Table 3-7 Expected 2012 Emission Reductions from Proposed New SIP Measures...............50 

Table 4-1 Future Year Growth Factor Summary......................................................................53 

Table 4-2 Motor Vehicle Growth Trends .................................................................................54 

Table 4-3 ARB Adjustments to Emissions Inventory Baseline................................................55 

Table 4-4 Summer Planning Day ROG Emissions...................................................................59 

Table 4-5 Summer Planning Day NOx Emissions ...................................................................60 

Table 4-6 Adjusted ROG Planning Emission Forecast by Major Source Category.................61 

Table 4-7 Adjusted NOx Planning Emission Forecast by Major Source Category .................62 

Table 4-8 SCC Air Basin Marine Emission Categories 2002 – 2012 ......................................65 

Table 4-9 OCS Air Basin Marine Emission Categories 2002 – 2012 ......................................67 

Table 4-10 Naval Base Ventura County Emissions Budget.......................................................69 

Table 5-1 RFP Demonstration ..................................................................................................73 

Table 8-1 CCAA Triennial Assessment Requirements ............................................................80 

Table 8-2 Expected Peak Day Ozone Concentrations..............................................................82 

Table 8-3 Control Measures Adopted or Amended 2003 – 2005.............................................85 

Table 8-4 Status of Control Measures Scheduled for Revision 2003 – 2005...........................86 

Table 8-5 Every Feasible/Further Study Control Measures – Detail .......................................88 
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LIST OF APPENDICES 

Appendix A Ventura County Transportation Control Measure Commitments....................... A-1 

Appendix B Ventura County Reasonably Available Control Measures Analysis...................B-1 

Appendix C Ventura County Emission Forecasts by Emissions Inventory 

Category Name ....................................................................................................C-1 

Appendix D Modeling and Attainment Demonstration .......................................................... D-1 
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ACRONYMS 

AB Assembly Bill 

APCB Air Pollution Control Board

APCD Air Pollution Control District

AQMD Air Quality Management District

AQMP Air Quality Management Plan

ARB Air Resources Board

BACT Best Available Control Technology

BARCT Best Available Retrofit Control Technology

BY Base Year 

CAAA Federal Clean Air Act Amendments

Caltrans California Department of Transportation

CCAA California Clean Air Act

CE Control Efficiency 

CEFS California Emission Forecasting System

CEQA California Environmental Quality Act

CF Control Factor 

CNG Compressed Natural Gas

CO Carbon Monoxide 

CTG Control Techniques Guidelines

CURB City Urban Restriction Boundary

District Air Pollution Control District

DMV Department of Motor Vehicles

DPR Department of Pesticide Regulation

EDPC Expected Peak Day Concentration

EIC Emissions Inventory Category

EITAC Emissions Inventory Technical Advisory Committee

EPA Environmental Protection Agency

EPP Early Progress Plan

ERC Emission Reduction Credit

FAA Federal Aviation Administration

FHWA Federal Highway Administration

FIP Federal Implementation Plan

FMVCP Federal Motor Vehicle Control Program

FTA Federal Transit Administration

FY Forecast Year 

GF Growth Factor 

GHG Greenhouse Gases 

HFC Hydrofluorocarbons

IP Implementation Factor

IPCC Intergovernmental Panel on Climate Change
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LAFCO Local Agency Formation Commission

MACT Maximum Achievable Control Technology

NAAQS National Ambient Air Quality Standards

NBVC Naval Base Ventura County

NO2 Nitrogen Dioxide 

NOx Nitrogen Oxides 

NSR New Source Review

OCS Outer Continental Shelf

PFCs Perfluorocarbons 

PM10 Respirable Particulate Matter

PM2.5 Fine Particulate Matter

pphm parts per hundred million

ppm parts per million 

PUR Pesticide Usage Report

RACM Reasonably Available Control Measure

RACT Reasonably Available Control Technology

RE Rule Effectiveness 

RFP Reasonable Further Progress

ROG Reactive Organic Compounds

RP Rule Penetration 

RTIP Regional Transportation Improvement Program

RTP Regional Transportation Plan

SAFETEA-LU Safe, Accountable, Flexible, Efficient Transportation Equity Act 

 A Legacy for Users 

SCAG Southern California Association of Governments

SCC South Central Coast

SCM Suggested Control Measure

SIP State Implementation Plan

SO2 Sulfur Dioxide 

SOAR Save Open Space and Agricultural Resources

TCM Transportation Control Measure

TOC Total Organic Compounds

UNFCCC United Nations Framework Convention on Climate Change 

VCTC Ventura County Transportation Commission

VMT Vehicle Miles Traveled

VOC Volatile Organic Compounds

WOE Weight of Evidence
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EXECUTIVE SUMMARY 

Purpose

Pursuant to the federal Clean Air Act Amendments of 1990 (CAAA), the Ventura County 2007 

Air Quality Management Plan (AQMP) presents Ventura County’s: 1) strategy to attain the 

federal 8-hour ozone standard; 2) attainment demonstration for the federal 8-hour ozone standard; 

3) reasonable further progress demonstration for the federal 8-hour ozone standard; and, 4) 

transportation conformity emissions budget for federal transportation conformity purposes. The 

2007 AQMP also presents Ventura County’s 2003 – 2005 Triennial Assessment and Plan Update 

required by the California Clean Air Act of 1988 (CCAA). 

Background

The CAAA established clean air plan requirements for areas that exceed the National Ambient 

Air Quality Standards (NAAQS). These areas, called nonattainment areas, must develop and 

implement clean air plans to attain the NAAQS by specified dates. Clean air plans are also called 

nonattainment plans or state implementation plans (SIP). 

Each state is responsible for implementing the CAAA within its jurisdiction. California state law

designates the California Air Resources Board (ARB) as California’s agency for all purposes set 

forth in the CAAA, including preparation of the California SIP. State law further specifies that 

the ARB must adopt clean air plans approved by local air districts, unless the ARB finds, after a 

public hearing, that a local clean air plan will not meet the requirements of the CAAA. ARB 

must submit SIPs and SIP revisions to the U.S. Environmental Protection Agency (EPA) for 

approval. 

The provisions and commitments in SIPs are federally enforceable. Moreover, the CAAA require 

that EPA impose sanctions on areas that fail to submit a SIP, fail to submit an adequate SIP, or 

fail to implement a SIP unless the state corrects such failures. Sanctions include 2-to-1 emission 

offsets for new air pollution sources and a ban on most federal highway grants. An additional ban 

on air quality grants is discretionary. Ultimately, EPA may impose a federal clean air plan, called 

a federal implementation plan (FIP), if EPA finds that the state failed to submit or implement an 

adequate SIP. 

In July 1997, EPA promulgated an 8-hour NAAQS for ozone. Based on Ventura County’s ozone 

levels over the previous three years, EPA designated Ventura County a moderate nonattainment 

area for the 8-hour ozone standard on June 15, 2004. Moderate ozone nonattainment areas must 

attain the federal 8-hour ozone standard by June 15, 2010. On February 14, 2008, ARB formally 

requested that EPA reclassify (bump up) Ventura County up one classification level to a serious 

8-hour ozone nonattainment area. This means that Ventura County must meet the federal 8-hour 

ozone standard by June 15, 2013. Although Ventura County will have more time to attain the 

8-hour standard, the serious classification requires Ventura County to meet the requirements for 

that higher classification, many of which are more stringent than for moderate areas. 
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Accordingly, in anticipation of becoming a serious area, the 2007 AQMP was prepared to satisfy 

the CAAA planning requirements for that classification. 

The CCAA was enacted on September 30, 1988. The goal of the CCAA is to achieve California’s 

more stringent health-based state clean air standards at the earliest practicable date. Under the 

CCAA, Ventura County is a severe nonattainment area for the state 1-hour ozone standard, and as 

such, must meet many of the CCAA’s most stringent requirements. For areas not meeting state 

ozone, carbon monoxide, sulfur dioxide, or nitrogen dioxide standards, clean air plans were 

required by July 1991. The CCAA also requires periodic plan updates and progress assessment 

reports. 

Attainment Strategy

Building on previous Ventura County AQMPs, the 2007 AQMP presents a combined local and 

state clean air strategy based on concurrent reactive organic compounds (ROG) and nitrogen 

oxides (NOx) emission reductions to bring Ventura County into attainment of the federal 8-hour 

ozone standard. ROG and NOx emitted by both anthropogenic and natural sources react in the 

atmosphere to produce photochemical smog, of which ozone is the principal constituent. Ventura 

County was the first area in the nation to institute such a strategy for meeting ozone standards. 

The local strategy includes the 1994 AQMP clean air strategy plus several new and further study 

emission control measures. 

The new control measures are proposed revisions to existing Ventura County Air Pollution 

Control District (APCD or District) rules that District staff has found practicable for Ventura 

County. The further study measures are proposals that may help Ventura County achieve the 

federal and state ozone standards but need additional air quality, feasibility, and environmental 

scrutiny before District staff can recommend them for adoption as District rules. They will 

become District rules only if District staff finds them to be practicable and appropriate for 

Ventura County. Both the new control measures and those further study measures recommended 

for adoption by District staff will also serve to meet the “every feasible measure” requirement of 

the CCAA. 

Several of the local control measures from the 1994 AQMP are not in the 2007 AQMP. In each 

case, District staff determined that the measure is either obsolete or infeasible for Ventura County 

based on technological or economic considerations. However, no control measure from previous 

AQMPs would be deleted from the 2007 AQMP that would slow the county’s progress towards 

attaining either the federal 8-hour ozone standard or the state ozone standards. 

Most of the emission reductions that Ventura County needs to attain the federal 8-hour ozone 

standard, and continue progress towards meeting the state ozone standards, will come from 

ARB’s 2007 State Implementation Plan (State Strategy). The State Strategy is a comprehensive 

and far-reaching set of emission reduction programs that focus on reducing emissions from 
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mobile sources, consumer products, and pesticides to significantly improve air quality throughout 

California and meet federal clean air standards for ozone and PM2.5. 

Attainment Demonstration

Photochemical modeling results indicate a design value of 0.087 parts per million (ppm) for 

Ventura County by 2013, the attainment date for serious ozone nonattainment areas. Based on 

photochemical modeling, as well as supporting analyses completed as part of the supplemental 

Weight of Evidence (WOE) evaluation, Ventura County can expect to reduce its design value 

to 0.084 ppm and attain the federal 8-hour ozone standard by 2013, the attainment date for serious 

nonattainment areas. Appendix D contains the entire photochemical modeling protocol and WOE 

for the 2007 AQMP.

Reasonable Further Progress Demonstration

In addition to showing attainment of the federal 8-hour ozone standard by 2013, the 2007 AQMP 

also must show steady progress towards attaining the federal 8-hour ozone standard by that date. 

Such steady progress towards attainment is called reasonable further progress (RFP). EPA 

defines RFP as “annual incremental reductions in air pollutant emissions as reflected in a State 

Implementation Plan that EPA deems sufficient to provide for the attainment of the applicable 

national ambient air quality standards by the statutory deadline.” The RFP demonstration shows 

that Ventura County will meet RFP requirements for the serious area milestone years 2008, 2011, 

and 2012. 

Transportation Conformity 

Transportation conformity is a CAAA and SAFETEA-LU regulatory process that coordinates air 

quality planning and transportation planning to help ensure that highway and transit projects will 

not cause new air quality violations, worsen existing violations, or delay timely attainment of the 

NAAQS. Central to transportation conformity are motor vehicle emissions budgets (also referred 

to as conformity budgets), which set the maximum amount of on-road mobile emissions that 

nonattainment areas can produce and continue to demonstrate progress towards attainment. 

Normally, conformity budgets are set with RFP Plans. However, EPA is revising its RFP 

regulations for areas whose air quality is dominated by air pollution transported from upwind 

regions. Ventura County is one of those areas. Until those revisions are complete, EPA will not 

approve conformity budgets for such areas. Therefore, to not disrupt Ventura County’s 

transportation planning process, nor jeopardize the county’s federal transportation funding, ARB 

has prepared an Early Progress Plan (EPP) for the county for the sole purpose of establishing a 

conformity budget for 2009, Ventura County’s attainment year as a moderate 8-hour ozone 

nonattainment area. 

On April 16, 2008, EPA found that the motor vehicle emissions budgets contained in Ventura 

County’s EPP adequate for transportation conformity decisions. Consistent with the 2004 final 

amendments to the Transportation Conformity Rule (69 FR 4004), the EPP 8-hour ozone 
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conformity budgets replace the existing 1-hour ozone conformity budgets in the 2004 AQMP. As 

a result, SCAG and the U.S. Department of Transportation must use these budgets in future 

conformity analyses in Ventura County. 

Notwithstanding the 2009 EPP conformity budget, the 2007 AQMP includes a conformity budget 

for Ventura County as a serious 8-hour ozone nonattainment area. Once the 2007 AQMP 

conformity budget is approved by EPA, it will supersede the EPP conformity budget and serve as 

the conformity budget for future transportation conformity determinations in Ventura County. 

Triennial Assessment

The purpose of the Triennial Assessment is to evaluate the county’s progress towards meeting the 

more stringent state 1-hour ozone standard, to incorporate new data and projections, and to 

identify and correct any deficiencies in meeting interim measures of progress. The Triennial 

Assessment shows that Ventura County is still making significant progress towards meeting that 

standard. Furthermore, state and local control programs in the 2007 AQMP for attaining the 

federal 8-hour ozone standard also will ensure that Ventura County continues making progress 

towards meeting the more stringent state 1-hour ozone standard. The Triennial Assessment has 

not identified any deficiencies with respect to meeting progress goals towards the state 1-hour 

ozone standard. However, the “every feasible measure” assessment conducted for the Triennial 

Assessment identified several existing District rules with potential for enhancement. The original 

due date for the Triennial Assessment was December 31, 2006. ARB has officially revised the 

due date to coincide with 2007 AQMP submittal. 

Air Quality Improvement

Air quality in Ventura County has improved dramatically since 1990, the 1994 AQMP base year. 

In 1990, our air quality exceeded the now revoked federal 1-hour ozone standard 18 times. 

However, in 2003 there were only two days over the federal 1-hour standard, and none in 

2004 and 2005. Likewise, all areas of the county have enjoyed similar reductions in 8-hour ozone 

levels. In 1990 there were 70 violations countywide of the federal 8-hour ozone standard, but 

only 11 in 2005, 17 in 2006, and 6 in 2007. These improvements have occurred despite a 

23.5 percent increase in Ventura County’s population since 1990. 

Important Partners

The District has not been working alone to improve Ventura County’s air quality. We have 

benefited greatly from efforts of ARB, EPA, the Southern California Association of Governments 

(SCAG), the County of Ventura and local cities, the Ventura County Transportation Commission 

(VCTC), county businesses, and the public. We look forward to these efforts continuing as we 

work towards attaining the federal and state ozone standards. 
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1. BACKGROUND 

Air pollution is hazardous to human health. It also diminishes the yield and quality of agricultural 

crops, reduces atmospheric visibility, degrades soils and materials, and damages native 

vegetation. Federal and state ambient air quality standards are set to protect public health and 

welfare, and minimize the effects of air pollution. These standards pertain to pollutants in 

ambient air, the air that people breathe outdoors. This plan focuses on one of those pollutants – 

ozone. Ventura County is designated an ozone nonattainment area for the state and federal ozone 

standards. 

Although the federal Clean Air Act has significantly improved our nation's air quality, many areas 

still have serious air quality problems. Ozone, the main constituent of smog, is the most serious 

and widespread air pollution problem in the country. Ozone forms in the atmosphere by a series 

of complex chemical reactions and transformations involving reactive organic gases (ROG) and 

nitrogen oxides (NOx) in the presence of sunlight. These “ozone precursor” pollutants come 

from a wide variety of sources such as gasoline vapors, fuel combustion, chemical solvents, and 

household products such as hairsprays, deodorants, and cleaners. 

Ozone is a pungent, colorless, toxic gas, consisting of three atoms of oxygen, that can chemically 

burn and cause narrowing of airways, forcing the lungs and heart to work harder to provide 

oxygen to the body. A powerful oxidant, ozone is capable of destroying organic matter – 

including human lung and airway tissue; it essentially burns through cell walls. Ozone damages 

cells in the lungs, making the passages inflamed and swollen. Ozone also causes shortness of 

breath, nasal congestion, coughing, eye irritation, sore throat, headache, chest discomfort, 

breathing pain, throat dryness, wheezing, fatigue, and nausea. It can damage alveoli, the 

individual air sacs in the lungs where oxygen and carbon dioxide exchange occurs. Ozone also 

has been associated with a decrease in resistance to infections. 

People most affected by ozone include the young, elderly, and athletes. Ozone may pose the 

worst health threat to people who already suffer from respiratory diseases such as asthma, 

emphysema, and chronic bronchitis, and those with cardiovascular diseases. Ozone also damages 

agricultural crops, native vegetation, and various natural and manufactured materials. 

California is divided into 15 air basins to regionally manage the state’s air resources. An air basin 

generally has similar meteorological and geographic conditions throughout. Ventura County is in 

the South Central Coast Air Basin, along with Santa Barbara and San Luis Obispo Counties. 

Each county in the air basin has its own air pollution control agency. The Ventura County Air 

Pollution Control District (APCD or District) is the air pollution control agency for Ventura 

County and, along with the California Air Resources Board (ARB), is charged by state law to 

protect the people and the environment of Ventura County from the harmful effects of air 

pollution. 
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Geographic areas in California that exceed clean air standards are called nonattainment areas. 

Ventura County is a nonattainment area for the federal 8-hour ozone standard. The Ventura 

County 8-hour ozone nonattainment area includes all of mainland Ventura County (including 

ocean areas out to three miles from the mainland shore) but excludes Anacapa and San Nicolas 

Islands. A map of the Ventura County 8-hour ozone nonattainment area is available on the U.S. 

Environmental Protection Agency (EPA) website. 

Ventura County is also nonattainment for the California 1-hour and 8-hour ozone standards. In 

Ventura County, ozone generally reaches peak levels by mid-afternoon and, along with ozone 

precursors, is often blown inland by the prevailing winds. Thus, inland areas such as Simi Valley, 

Thousand Oaks, Ojai, Fillmore, and Piru often have higher ozone levels and the most days over 

the federal and state ozone standards than the county’s coastal areas. The smoggiest days tend to 

occur from May through October (smog season) when high temperatures and stable atmospheric 

conditions produce conditions conducive to ozone formation and accumulation. 

Since its formation in 1968, the District has prepared many air quality documents to satisfy 

federal and state clean air requirements. The most important of these are the air quality 

management plans (AQMPs). AQMPs are not one-time documents, but are periodically updated 

and revised in response to changes in governing law and air pollution control science and 

technology. Moreover, each AQMP builds on its predecessor. Historical Ventura County 

AQMPs are described in Section 1.3.1. The Ventura County 2007 AQMP is the first Ventura 

County clean air plan for the federal 8-hour ozone standard. 

1.1. Purpose 

Pursuant to the federal Clean Air Act Amendments of 1990 (CAAA), the Ventura County 2007 

Air Quality Management Plan (AQMP) presents Ventura County’s: 1) strategy to attain the 

federal 8-hour ozone standard; 2) attainment demonstration for the federal 8-hour ozone standard; 

3) reasonable further progress demonstration for the federal 8-hour ozone standard; and, 

4) transportation conformity emissions budget for federal transportation conformity purposes. 

The 2007 AQMP also presents Ventura County’s 2003 – 2005 Triennial Assessment and Plan 

Update required by the California Clean Air Act of 1988 (CCAA). 

1.2. Federal 8-hour Ozone Attainment Status Reclassification 

CAAA Section 181(b)(3) allows federal nonattainment areas to voluntarily reclassify (bump up) 

to higher nonattainment classifications (e.g., from moderate to serious). This provision gives 

areas additional time to attain if they are doing everything practicable to attain but are not able to 

do so by their statutory attainment dates. EPA is obligated to grant voluntary bump-ups, but 

bumped-up areas must still attain as expeditiously as practicable and meet all CAAA 

requirements for their new, higher classifications. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 7 

On February 14, 2007, ARB formally requested that EPA bump up Ventura County from a 

moderate 8-hour ozone nonattainment classification to the serious 8-hour ozone nonattainment 

classification. This means that Ventura County’s new attainment deadline for the federal 8-hour 

ozone standard will be June 15, 2013. The voluntary bump-up is necessary because the 

photochemical modeling conducted for this plan shows that Ventura County may not attain the 

federal 8-hour ozone standard until then. 

A serious classification means that Ventura County will have to meet all of the requirements for 

that classification. The primary requirements include attainment as soon as practicable; a major 

new source threshold of 50 tons per year (down from 100 tons per year); a conformity threshold 

of 50 tons per year (also down from 100 tons per year); new source review (NSR) emission offset 

ratios of 1.2 to 1; and, rate of progress ROG/NOx emissions reductions of 18 percent by 2008, 

27 percent by 2011, and 30 percent by 2012. 

1.3. Federal Clean Air Act and Air Quality Standards 

On November 15, 1990, President George Bush signed the CAAA into law. The purpose of the 

CAAA is to provide clean, healthful air for all citizens of the country. The CAAA specifies dates 

by which areas of the country must meet the National Ambient Air Quality Standards (NAAQS). 

The EPA sets NAAQS as the maximum concentrations in the atmosphere for specific air 

contaminants in order to protect public health and welfare. The EPA has adopted NAAQS for 

ozone, carbon monoxide (CO), lead, nitrogen dioxide (NO2), fine particulate matter (PM2.5), and 

coarse particulate matter (PM10), and sulfur dioxide (SO2). Ventura County is designated 

nonattainment for the federal 8-hour ozone standard and attainment of all other federal air quality 

standards. 

The CAAA delegates primary responsibility for achieving the NAAQS to the states. The State 

Implementation Plan (SIP) is the principal mechanism for complying with the CAAA and 

meeting clean air standards. SIPs are “roadmaps” to clean air. A SIP outlines the actions, 

programs, and commitments each state will take to carry out its CAAA responsibilities to provide 

clean air for its citizens. The EPA must approve all SIPs and, once approved, are legally binding 

documents under both federal and state law. 

SIPs are not single documents, rather they are compilations of new and previously submitted 

plans, programs (such as air quality monitoring and modeling, permitting, etc.), district rules, 

state regulations, and federal emission controls. Many of California's SIPs rely on the same core 

set of control strategies, including emission standards for motor vehicles and stationary internal 

combustion engines, fuel regulations, and limits on emissions from consumer products. 

The ARB is the lead state agency for the California SIP. Local and regional air agencies, as well 

as other local and state agencies, such as the Southern California Association of Governments

(SCAG) and the Bureau of Automotive Repair, prepare SIP elements and submit them to ARB for 

review and approval. ARB then forwards the SIP revisions to EPA for approval and publication 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 8 MAY 2008 

in the Federal Register. The Code of Federal Regulations Title 40, Chapter I, Part 52, Subpart F, 

Section 52.220, lists all the items and elements included in the California SIP. 

1.3.1. Federal 1-hour Ozone Standard

In 1979, EPA established a NAAQS for ozone at 0.12 parts per million (ppm) in any one-hour 

period. The CAAA classifies areas based on the severity of each area's respective ozone problem. 

These classifications are marginal, moderate, serious, severe, and extreme. Areas with more 

severe air quality problems have progressively more requirements to meet under the CAAA. In 

addition, areas with higher nonattainment classifications also have later attainment dates. 

Marginal areas have the least amount of time to attain the standard; extreme areas have the most 

time. The EPA designated Ventura County a severe nonattainment area for the 1-hour ozone 

standard with an attainment deadline of November 15, 2005. 

The Ventura County Air Pollution Control Board (APCB or Board) last adopted AQMPs for the 

federal 1-hour ozone standard in 1994 and 1995. These plans committed the District to adopting 

additional ROG and NOx control measures to further reduce ambient ozone levels throughout 

Ventura County. Photochemical modeling demonstrated that Ventura County would attain the 

federal 1-hour ozone standard by 2005, the statutory attainment date. The EPA approved these 

plans on January 8, 1997 as part of the California SIP. 

In 1997, the APCB adopted the 1997 AQMP Revision. The 1997 AQMP Revision updated 

proposed adoption and implementation dates of several control measures in the 1995 AQMP 

Revision. The 1997 revision did not make any changes to rate of progress calculations or the 

District’s projected attainment date. EPA approved this plan revision on April 21, 1998. 

In 2004, the Ventura County Air Pollution Control Board adopted the 2004 AQMP Revision. 

That plan updated on-road motor vehicle emissions estimates and forecasts, established a 

transportation conformity budget for federal transportation conformity purposes, demonstrated 

that Ventura County would continue to reduce emissions, and that changes to the on-road motor 

vehicle emissions budget would not delay attainment of the federal 1-hour ozone standard. The 

EPA approved the 2004 AQMP Revision on May 28, 2004. 

In 2002, Ventura County achieved the 1-hour ozone standard. Despite meteorological conditions 

conducive to ozone formation, Ventura County has continued to meet the federal 1-hour ozone 

standard. 

1.3.2. Federal 8-hour Ozone Standard

Based on medical studies demonstrating that the 1-hour standard was inadequate for protecting 

public health, the EPA in 1997 replaced the federal 1-hour ozone standard with an 8-hour 

standard. This change lowered the standard for ozone from 0.12 ppm, averaged over one hour, to 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 9 

0.08 ppm, averaged over eight hours. The 8-hour standard is more stringent than the federal 

1-hour standard and better protects human health from the effects of smog. To attain the federal 

8-hour ozone standard, the three-year average of the annual fourth-highest daily maximum 8-hour 

ozone concentration in the county must not exceed 0.084 ppm. 

The American Trucking Association, the U.S. Chamber of Commerce, and other business groups 

legally challenged the 8-hour standard. The U.S. Court of Appeals upheld the challenges. EPA 

appealed the decision, and in 2001, the U.S. Supreme Court upheld the 8-hour ozone standard, but 

determined that EPA’s implementation strategy was unreasonable. In June 2003, EPA proposed a 

revised implementation strategy for the 8-hour ozone standard to address the Supreme Court 

findings, and finalized phases 1 and 2 of the strategy in the Federal Register on April 30, 2004 

and November 29, 2005, respectively. Effective June 15, 2005, the EPA revoked the federal 1-

hour ozone ambient air quality standard, including associated designations and classifications, in 

all areas of the country except 14 early action compact areas, none of which included Ventura 

County. 

The federal 8-hour ozone rule set new planning requirements for nonattainment areas. These 

requirements address such topics as classification and attainment deadlines, 1-hour ozone 

standard to 8-hour ozone standard transition, anti-backsliding provisions, reasonably available 

control technology (RACT), reasonable further progress (RFP) plans for 2002 - 2008, post-2008 

RFP plans, transportation control measures (TCMs), including reasonably available control 

measures (RACM), attainment demonstrations, and transportation and general conformity. 

As with the federal 1-hour ozone standard, 8-hour ozone nonattainment areas have increasingly 

stringent requirements based on the severity of their respective 8-hour ozone attainment status. 

On April 30, 2004, the EPA determined which areas violate the federal 8-hour ozone standard 

based on their design values. These attainment status designations became effective June 15, 

2004. Ventura County’s 8-hour ozone design value is 0.095 ppm. Based on that value, EPA 

designated Ventura County a moderate nonattainment area for the federal 8-hour ozone standard. 

Moderate areas must attain the federal 8-hour ozone standard by June 15, 2010. 

1.4. California Clean Air Act and Air Quality Standards 

The California Clean Air Act (CCAA) was enacted in 1988 and became effective January 1, 

1989. The purpose of the CCAA is to achieve the more stringent health-based state clean air 

standards at the earliest practicable date. The CCAA classifies areas that exceed the state clean 

air standards within four categories: moderate, serious, severe, and extreme, depending on air 

pollution levels, with higher classifications having progressively more stringent requirements. 

California has adopted ambient air quality standards for ozone, respirable particulate matter, fine 

particulate matter, carbon monoxide, nitrogen dioxide, sulfur dioxide, lead, visibility reducing 

particulates, sulfates, and vinyl chloride. Ventura County is designated a severe ozone 

nonattainment area for the state 1-hour ozone standard, and nonattainment for the state PM10 and 

PM2.5 standards. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 10 MAY 2008 

As a severe ozone nonattainment area, Ventura County must meet many of the most stringent 

requirements of the CCAA. Key CCAA requirements for severe ozone areas are: 

• a permitting program designed to mitigate emission increases from new or modified 

permitted sources; 

• application of best available retrofit control technology (BARCT) for existing sources; 

• provisions to develop area and indirect source control programs; 

• TCMs to substantially reduce the rate of increase in vehicle use; 

• TCMs to achieve an average commuter ridership of 1.5 persons per vehicle by 1999, and 

with no net increase in emissions after 1997; 

• measures to increase low-emission vehicle use in vehicle fleets; 

• reducing population exposure to unhealthful levels of air pollution; and, 

• submittal of an air quality plan to the ARB by July 1, 1991, and triennial updates 

thereafter. 

The CCAA also requires that districtwide air emissions be reduced at least five percent per year 

for each pollutant or its precursors (beginning in 1988), averaged every consecutive three-year 

period. A district may use an alternative strategy that achieves a smaller average reduction if: 1) 

the alternative strategy is equal to or more effective in improving air quality than the five percent 

per year approach; or, 2) despite the inclusion of every feasible measure in the plan and an 

expeditious adoption schedule, the district is still unable reduce emissions by at least five percent 

per year. 

The CCAA does not expressly require air quality plans for the state particulate matter standards. 

However, many of the control measures in the AQMP will reduce ambient PM levels by reducing 

ROG and NOx emissions. ROG and NOx can transform in the atmosphere into aerosols, which 

are a major constituent of atmospheric PM. 

1.4.1. California 1-hour Ozone Standard

In 1988, the ARB adopted the current state 1-hour ozone standard, 0.09 ppm, not to be exceeded. 

The Ventura County Air Pollution Control Board adopted the 1991 AQMP for the state 1-hour 

ozone standard on October 8, 1991. That plan contained many new and revised control measures 

to reduce air pollutants, but did not meet the required five percent per year reduction target. The 

CCAA requires any air district unable to achieve five percent annual emission reductions to 

demonstrate to ARB's satisfaction that it has included “every feasible measure” in its plan and an 

expeditious adoption schedule. Additionally, the 1991 AQMP did not demonstrate attainment of 

the state 1-hour ozone standard. Therefore, ARB classified Ventura County a severe 

nonattainment area for the state 1-hour ozone standard. ARB approved the 1991 AQMP on 

August 13, 1992, and, as part of that approval, ARB determined that the District's proposed 

control strategy met the “every feasible measure” requirement of the CCAA. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 11 

The 1994/5 AQMPs were prepared primarily to satisfy federal Clean Air Act requirements, but 

also satisfied the triennial assessment and plan update requirements of the California Clean Air 

Act. The District also submitted triennial assessments and plan updates in 2001 and 2004. 

1.4.2. California 8-hour Ozone Standard

In 2005, ARB approved a new state 8-hour-average ozone standard of 0.070 ppm, not to be 

exceeded. This new state 8-hour ozone standard became effective on May 17, 2006. ARB 

adopted first-time area designations for the new state 8-hour ozone standard in November 2006. 

Under state law, designations are by pollutant rather than averaging time. Therefore, there is only 

one designation for ozone, based on both the 1-hour and 8-hour standards. To be designated 

attainment, an area must attain both the 1-hour average and 8-hour average ozone standards. 

Because the District is nonattainment for the California 1-hour ozone standard, the District will 

continue to be designated a state ozone nonattainment area. No air plans are due for the state 8-

hour ozone standard. 

1.5. Progress in Improving Ventura County Air Quality 

1.5.1. Reduction in Ozone Levels

As shown in Figure 1-1, air quality in Ventura County has improved dramatically since 1990, the 

base year for the 1994 AQMP. In 1990, Ventura County had 18 days over the now revoked 

federal 1-hour ozone standard. However, in 2003 there were only two days over the federal 

1-hour standard, and none in 2004 and 2005. Likewise, all areas of the county have enjoyed 

similar reductions in 8-hour ozone levels. In 1990, there were 70 days countywide over the 

federal 8-hour ozone standard, but only 11 in 2005, 17 in 2006, and 6 in 2007. These 

improvements have occurred despite a 23.5 percent increase in Ventura County’s population 

since 1990. 

Over the same time, the county’s 8-hour ozone values used to determine compliance with the 

federal 8-hour ozone standard fell dramatically as well. The national 8-hour standard is violated 

when the average of the three annual fourth highest 8-hour averages over three years is greater 

than or equal to 0.085 ppm (after truncation to three decimal places). As shown in 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 12 MAY 2008 

Figure 1-2, the countywide 8-hour ozone value deceased from 0.13 ppm in 1990 to 0.090 ppm in 

2006. 

Figure 1-3 through Figure 1-5 present the corresponding 8-hour values for years 1990 through 

2006 for each county air quality monitoring station. Ozone data for 2007 is not yet available from 

ARB. For all stations, 8-hour ozone values have significantly decreased and are approaching, or 

are now lower than, the federal and state 8-hour standards. These trends should continue as local, 

state, and federal clean air programs continue to reduce air emissions responsible for ozone 

formation. 

Figure 1-1 

Countywide Days Over Federal & State Ozone Standards vs. Population Growth 

Sources: California Air Resources Board and 

California Department of Finance

0

20

40

60

80

100

120

140

160

180

1991

1993

1995

1997

1999

2001

2003

2005

2007

Days Exceeding Ozone Standard

250,000

350,000

450,000

550,000

650,000

750,000

850,000

950,000

Population

Fed 1-hr. State 1-hr. Fed 8-hr.

State 8-hr. Population
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 13 

Figure 1-2 

Countywide 8-Hour Ozone Values 

0.06

0.07

0.08

0.09

0.10

0.11

0.12

0.13

0.14

0.15

1991

1993

1995

1997

1999

2001

2003

2005

2007

Ozone in Parts per Million

Three Year Average of Fourth Highest Ozone Concentration, Truncated at 

Three Decimal Places. (Source: California Air Resources Board)

Federal Eight-hour Ozone Standard

State Eight-hour Ozone Standard

0.06

0.07

0.08

0.09

0.10

0.11

0.12

0.13

0.14

0.15

1991

1993

1995

1997

1999

2001

2003

2005

2007

Ozone in Parts per Million

Three Year Average of Fourth Highest Ozone Concentration, Truncated at 

Three Decimal Places. (Source: California Air Resources Board)

Federal Eight-hour Ozone Standard

State Eight-hour Ozone Standard

Figure 1-3 

8-Hour Ozone Values for Simi Valley & Ojai Valley 

0.06

0.07

0.08

0.09

0.10

0.11

0.12

0.13

0.14

0.15

0.16

1991

1993

1995

1997

1999

2001

2003

2005

2007

Ozone in Parts per Million

Simi Valley Ojai

Federal Eight-hour Ozone Standard

Three Year Average of Fourth Highest Ozone Concentration, Truncated at 

Three Decimal Places. (Source: California Air Resources Board)

State Eight-hour Ozone Standard

0.06

0.07

0.08

0.09

0.10

0.11

0.12

0.13

0.14

0.15

0.16

1991

1993

1995

1997

1999

2001

2003

2005

2007

Ozone in Parts per Million

Simi Valley Ojai

Federal Eight-hour Ozone Standard

Three Year Average of Fourth Highest Ozone Concentration, Truncated at 

Three Decimal Places. (Source: California Air Resources Board)

0.06

0.07

0.08

0.09

0.10

0.11

0.12

0.13

0.14

0.15

0.16

1991

1993

1995

1997

1999

2001

2003

2005

2007

Ozone in Parts per Million

Simi Valley Ojai

Federal Eight-hour Ozone Standard

Three Year Average of Fourth Highest Ozone Concentration, Truncated at 

Three Decimal Places. (Source: California Air Resources Board)

State Eight-hour Ozone Standard
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 14 MAY 2008 

Figure 1-4 

8-Hour Ozone Values for Piru & Thousand Oaks 

Federal Eight-hour Ozone Standard

State Eight-hour Ozone Standard

0.06

0.07

0.08

0.09

0.10

0.11

0.12

0.13

0.14

0.15

0.16

1991

1993

1995

1997

1999

2001

2003

2005

2007

Ozone in Parts per Million

Piru Thousand Oaks

Three Year Average of Fourth Highest Ozone Concentration, Truncated 

at Three Decimal Places. (Source: California Air Resources Board)

0.06

0.07

0.08

0.09

0.10

0.11

0.12

0.13

0.14

0.15

0.16

1991

1993

1995

1997

1999

2001

2003

2005

2007

Ozone in Parts per Million

Piru Thousand Oaks

Three Year Average of Fourth Highest Ozone Concentration, Truncated 

at Three Decimal Places. (Source: California Air Resources Board)

Figure 1-5 

8-Hour Ozone Values for Casitas Pass, Ventura, & El Rio 

0.06

0.07

0.08

0.09

0.10

0.11

0.12

0.13

0.14

0.15

0.16

1991

1993

1995

1997

1999

2001

2003

2005

2007

Ozone in Parts per Million

Casitas Pass Ventura El Rio

Federal Eight-hour Ozone Standard

State Eight-hour Ozone Standard

Three Year Average of Fourth Highest Ozone Concentration, Truncated 

at Three Decimal Places. (Source: California Air Resources Board)

0.06

0.07

0.08

0.09

0.10

0.11

0.12

0.13

0.14

0.15

0.16

1991

1993

1995

1997

1999

2001

2003

2005

2007

Ozone in Parts per Million

Casitas Pass Ventura El Rio

Federal Eight-hour Ozone Standard

State Eight-hour Ozone Standard

Three Year Average of Fourth Highest Ozone Concentration, Truncated 

at Three Decimal Places. (Source: California Air Resources Board)
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 15 

2. 2002 BASELINE EMISSIONS INVENTORY 

An emissions inventory is a large dataset that, as a whole, describes emission sources and 

quantifies pollutants released into the atmosphere. Ozone nonattainment areas, such as Ventura 

County, must develop and continue to update baseline inventories to evaluate federal, state, and 

local control programs and report emission reduction progress. A baseline year is a specific year 

used to gauge and evaluate past or future emission estimates. The 2002 emissions inventory is 

the baseline for forecasting future year emissions and from which the SIP inventories are derived. 

EPA identifies 2002 as the emissions inventory base year for the SIP planning process in the 

November 8, 2002 EPA memorandum, 2002 Base Year Emission Inventory SIP Planning: 8-

Hour Ozone, PM2.5 and Regional Haze Programs. 

This chapter summarizes the 2002 baseline ROG and NOx emissions inventory for the Ventura 

County ozone nonattainment area, and reports those pollutants in tons per day (TPD). 

Calculations are based on the ozone summer season (May – October), when temperature 

inversions and ozone formation potential are the greatest. Emission categories inactive or less 

active during the ozone summer months do not carry as much weight in the SIP inventory. 

Examples of inactive summer month emissions are activities such as orchard heating or wood 

fireplace heating. Focusing on the May through October months increases the analysis of ROG 

and NOx emissions, which are the concern of this plan. 

Table 2-1 presents the 2002 summary of summer day emissions, also referred to as “planning day 

emissions” for ROG and NOx, which are the most important pollutants in terms of the air 

chemistry and creation of ozone. ROG is not a pollutant that is directly measured but is the 

reactive fraction of the total organic compounds (TOC). Therefore, ROG excludes methane and 

other compounds with inconsequential effects on ozone photochemical reactivity. For a complete 

list of compounds that are considered non-reactive, refer to District Rule 2, under Definitions, 

Exempt Organic Compounds. 

Emissions data are compiled into major source categories and Ventura County emissions are also 

distinguished by onshore and offshore geographic areas. Onshore emissions include sources out 

to the 3-mile State Tidelands boundary area referred to in this document as the South Central 

Coast (SCC) Air Basin of Ventura County. Offshore emissions include sources in the Outer 

Continental Shelf (OCS) Air Basin, in waters beyond the 3-mile state boundary. Geographic 

boundaries distinguish the emissions in this chapter and Chapter 4. The analysis of emissions 

control responsibility falls into this geographic air basin division. 

2.1. Emissions Inventory Reporting Requirements 

This document complies with both state and federal emissions inventory reporting requirements 

in the update of the 2002 base year actual emissions (Chapter 2) and future year forecast 

methodology (Chapter 4). The federal emissions inventory requirements are included in the EPA 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 16 MAY 2008 

document, Emissions Inventory Guidance for Implementation of Ozone and Particulate Matter 

National Ambient Air Quality Standards (NAAQS) and Regional Haze Regulations. In addition, 

the California Health and Safety Code Sections 40913(4)(5), 40914(c), 40918(a) 40924(b) and 

40925(a) require emissions inventory review, correction, and incorporation of the most current 

emissions factors and growth and control data and future year forecast estimates. 

Table 2-1 

2002 Baseline Summer Planning Day Emissions 

 (tons/summer day) 

Both SCC and OCS Air Basins ROG NOx

Total Stationary and Area-wide Sources 24.83 7.74 

Total On-road Vehicle Sources 20.31 30.00 

Total Other Mobile Sources 15.22 37.45 

Total Emissions 60.36 75.19 

NOTES:

Source: CEFS v1.06 (November 2006). 

Totals include ARB external adjustments (3/06/2008). 

2.2. Emissions Inventory Major Categories 

The 2002 base year emissions inventory is an aggregate of two very general emission release 

types: 1) Stationary Sources, comprised of point sources and stationary area-wide sources, and 2) 

Mobile Sources, comprised of on-road mobile sources and other mobile sources. Stationary 

Sources are those that have a static geographic location and Mobile Sources are mobile in nature. 

ARB maintains the California Emission Inventory Development and Reporting System 

(CEIDARS), the statewide emissions inventory database, which includes the current reactive 

fractions used for ROG estimates. The air pollution control districts, such as Ventura County, 

provide updates to many categories using local, unique data. Figure 2-1 displays the pollutant 

distribution from these major categories and reflects the 2002 Baseline Summer Planning Day 

Emissions. 

2.2.1. Stationary Sources

Point sources are stationary emission sources identified on an individual basis due to the quantity 

or nature of their emissions. Examples of point sources include electrical power generating 

plants, large surface coating operations, and petroleum production facilities. Initially, point 

sources are identified through the District's Permit to Operate evaluation or during the rule 

development process. Permitted stationary sources are inspected annually, subject to air pollution 

rules applicable to specific facility operation. In addition, the District surveys the point source 

facilities annually to document changes to equipment and gather activity data and uses that data to 

calculate and update annual emissions. There were eight NOx point sources emitting greater than 

25 tons per year and four ROG point sources emitting greater than 25 tons per year in 2002; these 

are considered “major” sources under CAAA Section 182(d). The District accounted for 

approximately 1,400 stationary sources in the 2002 baseline emissions inventory. Those major 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 17 

stationary sources are in the point source inventory and smaller sources are reflected in the 

stationary area-wide source categories. 

Figure 2-1 

2002 Baseline Summer Planning Day Emissions 

Pollutant Distribution 

0

5

10

15

20

25

30

35

40

tons/summer day

Total Stationary and

Area-w ide Sources

Total On-road Vehicles Total Other Mobile

Sources

ROG

NOx

Stationary area-wide sources are groups of similar emission sources that do not individually 

contribute significant amounts of pollutants, but when aggregated can contribute significant air 

emissions. Examples include consumer products (hairspray), gasoline station emissions, and 

residential heating emissions. 

Emissions from area sources are determined in a variety of ways. One accepted estimation 

method, generally referred to as the “bottom-up” method, surveys local end users of an emission 

source product, such as organic solvents, to obtain specific countywide data by those industries 

using the product. Another estimation method, referred to as the “top-down” approach, evaluates 

the emissions based on a single emission source, such as architectural painting. The larger 

national or statewide data are gathered and apportioned down to the county level based on 

distribution factors representative of Ventura County. 

Every year District staff evaluates the data and methods used in order to improve and update the 

emissions inventory. ARB and District staff coordinates the update process through the state’s 

Emissions Inventory Technical Advisory Committee (EITAC). Currently, hundreds of new 

emission categories are available since the previous AQMP (1990 base year) was developed. The 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 18 MAY 2008 

refinement of the emissions categories is ongoing and necessary to better classify and quantify the 

emissions, and to evaluate feasibility of new control technologies and cost-effectiveness of 

controls when developing state or local rules. Summaries of the area source methodologies are 

posted on the ARB’s Index of Methodologies website. 

2.2.2. Mobile Sources

There are two major source categories for mobile sources, On-Road Motor Vehicles, and Other 

Mobile Sources. ARB calculates mobile source emissions with input from detailed mobile source 

emission models known as the EMFAC On-road Model and the OFFROAD emissions model. 

Mobile sources, as a whole, contribute the largest amount of criteria air pollutants into the air 

statewide. Appendix C of this document includes a summary and general description of the OnRoad Motor Vehicle emissions by Emissions Inventory Code (EIC). Complete documentation for 

mobile source category emissions is available at the following website: 

http://arb.ca.gov/msei/msei.htm, on the ARB mobile source main page for the EMFAC on-road 

mobile source model, and the OFFROAD mobile source model. 

2.2.2.1. On-Road and Off-Road Emissions

The on-road mobile emissions are updated to reflect changes from the latest SCAG 2008 

Regional Transportation Plan (RTP), California Department of Transportation (Caltrans), and the 

Department of Motor Vehicles (DMV) motor vehicle related data used in the ARB emissions 

model. 

The 2002 base year and future year emissions are calculated using the current socioeconomic data 

in the SCAG regional transportation model for the 2008 RTP. The SCAG transportation model 

outputs are used in the EMFAC models. On-road motor vehicle emissions are based on ARB’s 

EMFAC07v2.3 runs, dated March 12, 2008. 

2.2.2.2. Other Mobile Sources

Other Mobile Sources encompass a wide variety of off-road equipment referred to as off-road 

emission sources. The major categories include emissions from aircraft, locomotives, commercial 

and recreational marine vessels, agricultural, construction, lawn and garden, and off-road 

recreation vehicles, and from hedge trimmers to cranes. 

ARB estimates the majority of off-road emissions using the OFFROAD mobile source emissions 

model. OFFROAD is an integrated statewide model that estimates population, activity, and 

emissions for specific categories of equipment and fuel types at the county level. OFFROAD is 

used to generate base year emissions and to project changes in future inventories of mobile source 

emissions. However, some categories such as locomotives, ocean-going vessels, and harbor craft 

are estimated in individual modules external from the OFFROAD model. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 19 

Additional information on ARB’s Off-Road Emissions Inventory Program and the OFFROAD 

model is available on ARB’s website at: http://www.arb.ca.gov/msei/offroad/offroad.htm. 

Table 2-2 presents the baseline emissions by major source category for the South Central Coast 

Air Basin (SCC) and Figure 2-2 and Figure 2-3 exhibit those emissions in percentages of ROG 

and NOx by major source category. 

Table 2-2 

2002 Baseline Planning Emissions by Major Source Category 

Ventura County South Central Coast (SCC) Air Basin (tons/summer day)

Major Source Category Name ROG NOx 

Stationary Sources 

 Fuel Combustion 0.76 5.88 

 Waste Disposal 0.09 0.09 

 Cleaning and Surface Coatings 6.30 0.00 

 Petroleum Production and Marketing 3.10 0.04 

 Industrial Processes 0.37 0.08 

 Total Stationary Sources 10.62 6.08 

Area-wide Sources 

 Solvent Evaporation 13.53 0.00 

 Miscellaneous Processes 0.59 1.27 

Total Area-wide Sources 14.12 1.27 

Mobile Sources 

 On-Road Motor Vehicles 20.31 30.00 

 Other Mobile Sources 14.59 24.49 

 Total SCC Mobile Sources 34.90 54.49 

TOTAL SCC AIR BASIN 59.64 61.83 

NOTES: 

Source: CEFS v.1.06 (November 2006). 

Includes ARB Adjustments (03/06/2008) and Revised On-Road Vehicles Emissions (03/12/2008). 

Excludes OCS and Natural Sources. 

Data rounding may affect totals. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 20 MAY 2008 

Figure 2-2 

Ventura County 2002 Planning Day 

ROG Emissions Inventory 

59.64 tons/summer day

Other

3% Solvent Use

27%

On-Road Vehicles

34%

Pesticide Application

7%

Petroleum Industry

5%

Other Mobile 

Sources

24%

Reference: 

ARB CEFS v1.06. 

Includes ARB Adjustments (03/06/2008). 

OCS excluded.

Figure 2-3 

Ventura County 2002 Planning Day 

NOx Emissions Inventory 

61.83 tons/summer day

On-Road Vehicles

49%

Electric Utilities

2%

Other Fuel 

Combustion

9%

Other Mobile 

Sources

14%

Mobile Equipment

25%

Petroleum Industry

0.5%

Reference: 

ARB CEFS v1.06. 

Includes ARB Adjustments (03/06/2008). 

OCS excluded. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 21 

2.3. Ventura County Marine Emissions Inventory 

Marine emission sources include marine related activities in the State Tidelands boundary area, 

within three miles of the Ventura County coastline. ARB defines this area as being part of the 

South Central Coast (SCC) Air Basin, which is composed of Ventura, Santa Barbara, and San 

Luis Obispo counties. The Ventura County portion of the SCC Air Basin includes the onshore 

marine activities of Ventura County and the Port of Hueneme and its approach corridors. Any 

reference in this document to the SCC Air Basin is specifically referring to only the Ventura 

County portion of the larger air basin. 

Offshore marine emission sources occur in the region beyond the three-mile State Tidelands 

boundary, in the Outer Continental Shelf (OCS) and include the offshore shipping lanes in the 

Santa Barbara Channel and San Nicolas Island. The OCS region includes those waters between 3 

and 100 miles from shore. The OCS emissions are significant and are included in the 

photochemical modeling used to demonstrate attainment of the 8-hour ozone standard. However, 

only emissions in the Ventura County portion of the SCC Air Basin are relevant to Ventura 

County’s ozone nonattainment area. 

Emission sources related to marine activities are a significant part of the overall base year 

emissions inventory for Ventura County. ARB undertook an extensive process to develop a new 

statewide emission inventory for several important categories of marine emission sources used for 

the 8-hour Ozone SIP and ozone attainment modeling. ARB staff, in cooperation with local 

districts, developed a 2002 base year consistent statewide emissions estimation methodology for 

ocean-going vessels operating in California coastal waters, ports and inland waterways. The 

methodology reflects updated vessel population and operational data, engine characteristics and 

emission factors for ocean-going vessels statewide. 

2.3.1. Ventura County Portion of the South Central Coast Air Basin

Coastal emission sources in the SCC Air Basin in Table 2-2 include Ships and Commercial Boats, 

Recreational Boats and Cargo Handling Equipment in the Off-Road Equipment category. 

Cumulatively these categories account for over 4 tons/day ROG and 3 tons/day NOx in 2002. 

Ships and Commercial Boats are comprised of large commercial ocean-going vessels calling on 

Port Hueneme, smaller commercial boats and harbor craft, and military vessels affiliated with the 

U.S. Navy. Together these sources generate 1.4 tons/day NOx in 2002. Categories of oceangoing vessels include auto carriers, bulk cargo carriers, container vessels, passenger vessels, rollon/roll off vehicle carriers, refrigerated cargo vessels, and tankers. Of the over 300 ocean-going 

vessels calling on Port Hueneme annually, the majority are auto carriers and refrigerated produce 

vessels. 

NOx emissions from ocean-going vessels are 17% of the coastal total in 2002. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 22 MAY 2008 

Commercial Boats and Harbor Craft include commercial fishing vessels, charter fishing vessels, 

excursion boats, tug and towboats, and crew and supply boats associated with the four offshore 

oil and gas production platforms. Over 75% of the commercial boats in Ventura County are 

commercial fishing boats. Commercial boats contribute over 21% of coastal NOx in 2002. 

Military vessel operations occur at the U.S. Navy facilities at the Port of Hueneme and include 

large naval ships, smaller support and operations vessels, tugboats, and other vessels, including 

some non-military vessels utilizing Navy facilities. Military vessels account for 6% of coastal 

NOx emissions in 2002. 

Recreational Boats include vessels with outboard, inboard and stern-drive engines, sailboat 

auxiliary engines, and personal watercraft. Recreational vessels account over 90% or over 

3.8 tons/day of the coastal ROG emissions in 2002 and 30% of NOx, about 0.9 tons/day. 

Cargo Handling Equipment in the coastal waters include port operations/cargo handling 

equipment operating in association with large commercial vessels calling on Port Hueneme, such 

as yard tractors, forklifts, cranes, loaders, and other material handling equipment. Cargo 

Handling Equipment contributes about 0.8 tons/day or one quarter of coastal NOx in 2002. 

2.3.2. Outer Continental Shelf Air Basin Marine Emissions

Marine activities are even more significant emission sources in the OCS Air Basin. As presented 

in Table 2-3, Figure 2-4, and Figure 2-5, emissions from Ships and Commercial Boats, including 

large commercial ocean-going vessels, smaller commercial boats, and military vessels, comprise 

the vast majority of emissions in the OCS Air Basin, almost 13 tons/day NOx, or over 96%, and 

over 77% of total ROG. 

Commercial Ocean-going Vessels traversing the Santa Barbara Channel shipping lanes offshore 

of Ventura County include vessels calling on Port Hueneme or the ports of Los Angeles/Long 

Beach, and transiting vessels passing through southern California waters but without calling at 

either port. Over 10 tons/day of NOx in 2002 came from ocean-going vessels, about 77% of total 

NOx in the OCS, as well as over 39% of total ROG. Commercial boats include commercial and 

passenger charter fishing boats, excursion boats, tugboats and crew & supply boats affiliated with 

the offshore oil and gas production platforms. Commercial boats contribute over a third of 

offshore ROG and 2.3 tons/day of NOx emissions in 2002. 

Military Vessels are large naval vessels, smaller support vessels, and tugboats operating offshore 

and in the approach corridors to Port Hueneme. Military Vessels account for about 5% of 2002 

offshore ROG and less than 3% of NOx. In addition, aircraft emissions are associated with 

military aircraft operations at the U.S. Naval facility on San Nicolas Island, including transports, 

jet aircraft, and helicopters. The military aircraft activities are responsible for over 10% of 

offshore ROG emissions in 2002. Table 2-3 shows total emissions from these operations. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 23 

Stationary Sources are responsible for considerably smaller offshore emissions than Mobile 

Sources, about 13% of total offshore ROG and 3% of NOx. Oil & Gas Production ROG 

emissions include fugitive hydrocarbon losses from oil and gas production components and 

production and processing equipment on the off-shore oil and gas production platforms. Other 

offshore emission sources contributing less than 5% of total offshore ROG or NOx include 

electric generating types of equipment, natural gas flaring, and routine maintenance operations for 

the offshore oil and gas production platforms and the U.S. Naval facility on San Nicolas Island, 

all of which are permitted point sources. 

Table 2-3

2002 OCS Baseline Planning Emissions 

by Emissions Inventory Category Name 

Ventura County 

Outer Continental Shelf (OCS) Air Basin (tons/summer day)

Emissions Category Name ROG NOx 

Stationary Sources 

 Fuel Combustion 

 Oil and Gas Production (Combustion) 0.01 0.15 

 Service and Commercial 0.02 0.24

 Total Fuel Combustion 0.03 0.39 

 Cleaning and Surface Coatings 

 Coatings and Related Process Solvents 0.01 0.00

 Total Cleaning and Surface Coatings 0.01 0.00 

 Petroleum Production and Marketing 

 Oil and Gas Production 0.04 0.01 

 Petroleum Marketing 0.00 0.00

 Total Petroleum Production and Marketing 0.04 0.01 

 Total OCS Stationary Sources 0.09 0.40 

Mobile Sources 

 Other Mobile Sources 

 Aircraft 0.07 0.04 

 Ships and Commercial Boats 0.56 12.92

 Total Other Mobile Sources 0.63 12.96 

 Total OCS Mobile Sources 0.63 12.96 

TOTAL OCS AIR BASIN 0.72 13.36 

NOTES: 

Source: CEFS v1.06 (November 2006). 

No ARB adjustments needed for OCS. 

Excludes Natural Sources. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 24 MAY 2008 

Figure 2-4 

Ventura County 2002 Planning Day 

ROG Emissions Inventory (OCS Air Basin) 

0.72 tons/summer day

Ships in Transit

39%

Commercial 

Boats

33%

Coating/

Solvent Use

2%

Oil And Gas 

Production

6%

Fuel 

Combustion

5%

Other 

Vessels

5%

Aircraft

10%

Reference: 

ARB CEFS v1.06 (November 2006). 

OCS is 3 – 100 miles offshore. 

Figure 2-5 

Ventura County 2002 Planning Day 

NOx Emissions Inventory (OCS Air Basin) 

13.36 tons/summer day

Ships in Transit

77%

Fuel 

Combustion

3%

Tugboats

2%

Other Vessels/

Aircraft

3%

Commercial 

Boats

15%

Reference: 

ARB CEFS v1.06 (November 2006). 

OCS is 3 – 100 miles offshore. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 25 

3. CONTROL STRATEGY 

This chapter presents the control strategy for the 2007 AQMP to achieve the federal 8-hour ozone 

standard. Since 1979, Ventura County’s ozone strategy has been concurrent ROG and NOx 

emission reductions from stationary and mobile sources. Ventura County was the first area in the 

nation to institute a dual ROG/NOx strategy for meeting state and federal clean air standards for 

ozone. 

The 2007 AQMP control strategy consists of a local component implemented by the District and 

a combined state and federal component implemented by the ARB and EPA. The District has 

primary responsibility for regulating stationary sources, including some area sources, within 

Ventura County. The ARB regulates on-road motor vehicles, some off-road mobile sources, and 

consumer products, and sets motor vehicle fuel specifications in California. The EPA regulates 

emissions from locomotives, aircraft, heavy-duty trucks used in interstate commerce, and some 

off-road engines exempt from state authority or best regulated at the national level. State and 

federal laws prohibit local air districts from regulating mobile sources. 

The District’s component of the 2007 AQMP control strategy consists of cost effective stationary 

source control measures, TCMs, and the District’s voluntary mobile source incentive programs. 

Most of these local control program elements were in previous Ventura County clean air plans. 

California air agencies, including this air district, have aggressively pursued measures to meet 

state and federal clean air standards and have developed many of the most innovative and 

effective clean air strategies in the world. 

Ventura County, along with other California air agencies, long ago implemented clean air 

measures that other parts of the country are just now considering. By 2002, the District fully 

implemented most of the local control measures in earlier Ventura County AQMPs, and most 

stationary sources in the county are now subject to stringent clean air regulations. Consequently, 

new local emission reductions are becoming ever smaller and often not economically or 

technologically feasible for sources in Ventura County. The percentage of total countywide ROG 

and NOx emissions (OCS Air Basin excluded) under District authority to regulate has been 

shrinking for many years and is now less that 50 percent. 

ARB’s component of the 2007 AQMP control strategy consists of its new State Strategy for 

California’s 2007 SIP, a comprehensive clean air strategy designed to achieve federal air quality 

standards through a combination of technologically feasible, cost effective, and far-reaching 

measures. It describes the scope of California’s ozone and fine particulate matter (PM2.5) 

nonattainment problems and presents ARB staff’s recommendations on how California can 

comply with federal clean air standards. 

As elsewhere in California, Ventura County’s ongoing progress towards clean air depends largely 

on current and proposed mobile source strategies under state and federal jurisdiction. District 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 26 MAY 2008 

efforts will nonetheless remain crucial for Ventura County to attain and maintain state and federal 

clean air standards. 

3.1. Stationary Source Control Measures 

Stationary source control measures are equipment and techniques for reducing air pollutant 

emissions from stationary sources. Examples of stationary source control measures include vapor 

collection systems on gasoline and oil storage tanks, landfill gas recovery systems, and replacing 

internal combustion engines with electric motors. Control measures provide the framework for 

District clean air rules that reduce ROG and NOx emissions. ARB’s Ventura County APCD List 

of Current Rules website lists all District rules referenced in this and other sections of the 2007 

AQMP. 

3.1.1. Control Measures with Emission Reductions Beyond the Base Year

This section presents ROG and NOx control measures already adopted as APCD rules but not 

fully implemented by the end of 2002, the base year for the 2007 AQMP. Table 3-1 presents 

these measures with expected emission reductions expressed in tons per day. The District will 

continue to implement these measures. 

3.1.2. New Stationary Source Control Measures

This section presents new stationary source control measures recommended for inclusion in the 

2007 AQMP as part of Ventura County’s strategy to attain the federal and state ozone standards. 

In each case, the new measure is a proposed revision to an existing District rule. Table 3-2 

summarizes these measures. The new measures also serve to meet the “every feasible measure” 

requirement of the California Clean Air Act (see Section 8.6). The emission forecasts do not 

reflect emission reductions from these measures. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 27 

Table 3-1 

Stationary Source Control Measures - Local Control Measures Only 

 Summer Planning Day Emissions (tpd)

 Year 

CM District Adopted/ Year 2002 2008 2011 2012 

Number Control Measure Name Rule Amended Impl’d. (Emission Reductions) 

ROG Control Measures 

R-303 Architectural Coating 74.2 1991 1992 0.02 0.00 0.00 0.00 

R-306 Wood Product Coating 74.30 1994 2006 0.07 0.00 0.00 0.00 

R-314 Adhesives 74.20 1993 1995 0.20 0.03 0.03 0.03 

R-316 Graphic Arts Solvents 74.19 1992 1993 0.20 0.01 0.01 0.01 

R-321 Pleasure Craft Coating 74.24.1 1998 1999 0.00 0.00 0.00 0.00 

R-328 Surface Cleaning & Degreasing a

 74.6 & 

74.6.1 

2003 2004 3.12 1.07 1.12 1.14 

R-501 Fiberglass/Polyester Resin Use 74.14 2005 2005 0.02 0.00 0.00 0.00 

R-504 Restaurant Cooking Operations 74.25 2004 2005 0.05 0.01 0.01 0.01

Total ROG Control Measure Emissions 3.68 1.13 1.18 1.19

NOx Control Measures 

N-102 Boilers, Steam Gen, Heaters 

<1MMBtu 

74.11.1 1999 2000 0.10 0.04 0.05 0.05 

N-110 Fan Type Central Furnaces 74.22 1993 1994 0.20 0.07 0.11 0.12

Total NOx Control Measure Emissions 0.31 0.11 0.16 0.17

NOTES: a

 Every feasible measure. 

Data rounding may affect displayed values and totals. 

Table 3-2 

New Stationary Source Control Measures 

CM 

Number 

District 

Rule Control Measure Name 

Proposed Rule 

Adoption 

Proposed Rule

Implementation 

R-311 74.18 Motor Vehicle & Mobile Equipment Coating Operations 2008 2010 

R-332 74.12 Surface Coating of Metal Parts and Products 2008 2009 

R-329 74.2 Architectural Coatings TBD a

 TBD 

R-606 74.29 Soil Decontamination Operations 2008 2009 

NOTES: 

Emission reductions from these new measures are not reflected in the emission forecasts. 

This table does not list control measures fully implemented before 2002. 

a

 To be determined. 

R-311, Motor Vehicle & Mobile Equipment Coating Operations: This control measure would 

revise District Rule 74.18, Motor Vehicle and Mobile Equipment Coating Operations, to 

incorporate the requirements of ARB’s suggested control measure (SCM) for automotive 

refinishing. The proposed rule revision would establish volatile organic compound (VOC) limits 

for specific automotive refinishing categories. It would also prohibit anyone from applying, 

manufacturing, blending, repackaging for sale, supplying, offering for sale, distributing, 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 28 MAY 2008 

possessing, or selling any automotive coating that does not meet the VOC limits, except when the 

coating is sold for use with an approved emission control systems that is at least 85 percent 

efficient. The proposed standards also specify the manner in which the coatings may be applied. 

The SCM also prohibits the use of solvents that exceed a VOC content limit of 25 grams per liter, 

and specifies that any VOC-containing materials or products must be stored in closed, vapor-tight 

container when not in use and spray guns must be cleaned in a closed system or its approved 

equivalent. 

ARB staff estimates that the cost effectiveness of the SCM to be $1.43 per pound of VOC 

reduced, which compares favorably with the cost effectiveness of similar measures such as the 

2000 Architectural Coatings SCM ($3.20 per pound of VOC reduced). The average annual cost 

to automotive refinishing facilities is estimated to be $3,400.

The proposed District rule only addresses the VOC coating limits of the SCM. Adoption of the 

SCM provisions pertaining to VOC solvent content limits will occur later to give District staff 

time to study their feasibility for application in Ventura County. 

 District Rule: 74.18 

 Proposed Rule Adoption Date: 2008 

 Proposed Rule Implementation Date: 2010 

 Required Board Action: Adoption of a rule revision 

 Cost-effectiveness: $1.43 per ton of VOC reduced (overall) 

 Control Efficiency: 50% 

 Emission Reductions: 0.23 tons per day, ROG 

R-332, Surface Coating of Metal Parts and Products: This control measure would reduce ROG 

emissions from general purpose, single component, air-dry metal coatings and from solvents used 

for substrate cleaning, spray gun cleaning, and general cleanup through two revisions to District 

Rule 74.12, Surface Coating of Metal Parts and Products.

The revised rule would limit the ROG content of general air-dry coatings to 2.3 lb/gallon. In 

addition, the rule would also limit the “Multi- Component Coatings” category with an ROG 

content limit of 2.8 lb/gallon. This category excludes other listed specialty multi-component 

coatings. The revised rule would also limit the solvents used for substrate cleaning, spray 

equipment cleaning, and general cleanup to no more than 25 grams per liter (0.21 lb/gallon). 

Spray gun washers would no longer be required but recommended. 

These revisions are based on similar coating categories and standards in South Coast Air Quality 

Management District (AQMD) Rule 1107, Coating of Metal Parts and Products. The second 

revision reduces the ROG content limit for surface preparation and cleanup solvents to 25 grams 

of ROC per liter (0.21 lb/gal). This limit also appears in South Coast AQMD Rule 1171, Solvent 

Cleaning Operations. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 29 

The cost-effectiveness of replacing certain 2.8 lb/gal coatings with 2.3 lb/gal coatings is $15,441 

per ton of ROC reduced. The cost-effectiveness of the proposed low-ROC solvent requirement 

ranges from $359 per ton of ROC reduced to $6,470 per ton. 

The revisions to Rule 74.12 would reduce actual ROG emissions from the coating of metal parts 

and products about 19 percent, or 0.02 tons per day. About 36 percent of the emission reductions 

would result from the change in coating requirements. The remaining 64 percent would result 

from the proposed 25 g/l threshold for cleaning solvents. 

 District Rule: 74.12 

 Rule Adoption Date: 12/08 

 Rule Implementation Date: 6/09 

 Required Board Action: Adoption of a rule revision 

 Cost-effectiveness: Coating solvent limit - $15,441 per ton of ROC reduced 

 Cleaning solvent limit - $359 per ton of ROC reduced to $6,470 per ton of ROC reduced 

 Control Efficiency: 19% (overall) 

 Emission Reductions: 0.02 tons per day (overall), ROG 

R-329, Architectural Coatings: This control would revise District Rule 74.2, Architectural 

Coatings, to incorporate the requirements of ARB’s revisions to its SCM for architectural 

coatings. The purpose of the revisions is to enhance the effectiveness of the SCM to obtain ROG 

emission reductions. The changes include lowering VOC content limits for several coating 

categories, adding new coating categories, and deleting several coating categories because they 

are no longer needed as separate SCM categories. The revised SCM also contains revised coating 

category definitions either for clarification purposes or to improve rule enforcement. In addition, 

ARB staff found that some definitions required revision, based on their analyses of data submitted 

for the 2005 Architectural Coating Survey. The ARB adopted the SCM in October 2007.

 District Rule: 74.2 

 Proposed Rule Adoption Date: To be determined 

 Proposed Rule Implementation Date: To be determined 

 Required Board Action: Adoption of a rule revision 

 Cost-effectiveness: Being determined 

 Control Efficiency: Being determined 

 Emission Reductions: Being determined, ROG 

R-606, Soil Decontamination Operations: This measure would revise District Rule 74.29, Soil 

Decontamination Operations, to incorporate various enhancements. The purpose of the 

enhancements is to obtain further emission reductions from soil decontamination operations. The 

proposed revisions include controlling emissions during transport of contaminated soil; treating or 

removing contaminated soil within 30 days of excavation; lowering various exemption levels; 

prohibiting off-site soil aeration; keeping active soil storage piles wet or covered; covering 

inactive storage piles within one hour; and monitoring excavation sites. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 30 MAY 2008 

 District Rule: 74.29 

 Proposed Rule Adoption Date: 2008 

 Proposed Rule Implementation Date: 2009 

 Required Board Action: Adoption of a rule revision 

 Cost-effectiveness: Being determined 

 Control Efficiency: Being determined 

 Emission Reductions: Being determined, ROG 

3.1.3. Further Study Control Measures

Further study measures are emission control methods that are not proposed for adoption as 

District rules at this time, due to inconclusive information about their technical feasibility, 

economic feasibility, or appropriateness for Ventura County. District staff will evaluate these 

measures and will adopt them as District rules if they prove feasible and appropriate for Ventura 

County. 

California Health and Safety Code Section 40914(b)(2) requires that the District’s clean air plan 

for the California ambient ozone standards include expeditious implementation of “every feasible 

measure” to reduce ozone precursor emissions, ROG and NOx. Measures that help Ventura 

County attain the state ozone standard also help the county attain the federal 8-hour ozone 

standard. 

District staff reviewed the District’s rules for its periodic rule evaluation for the California Clean 

Air Act. This review determined that the rules listed in Table 3-3, Further Study Control 

Measures, have potential for enhancement, thereby realizing additional emission reductions for 

both the federal and state ozone standards. Consequently, the District rules listed in Table 3-3 

will serve a dual purpose. They will serve as potential measures for the District’s federal 8-hour 

ozone plan and will meet the “every feasible measure” requirement for the state ozone standard. 

In addition, staff identified a potential new rule for oil well degassing operations. This measure, 

if shown to be economically and technologically feasible in Ventura County, would control ROG 

emissions when natural gas is vented prior to repair work on oil wells. The emission reduction 

potential is unknown at this time but is likely significant. 

Section 8.6 presents further information regarding these rules. The District commits to 

rulemaking for these measures, during which District staff will evaluate the feasibility of each 

measure for Ventura County. For measures found feasible through the rulemaking process, 

District staff will provide emission reduction estimates prior to rule adoption. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 31 

Table 3-3 

Further Study Control Measures 

CM 

Number 

District 

Rule Control Measure Name 

Rulemaking

Schedule 

R-316 a 74.19 Graphic Arts 2008 

R-330 74.6 Surface Cleaning & Degreasing TBD b

R-331 74.6.1 Batch Loaded Vapor Degreasers TBD 

R-431 70 Storage and Transfer of Gasoline TBD 

R-432 None Oil Well Degassing 2009 

Various a

 Various Coating Rules (74.12, 74.13, 74.21, 74.24, 74.30) 2008 

NOTES: a Further evaluation for RACT compliance (See Section 3.1.6.1). 

b To be determined.

3.1.4. Reasonably Available Control Measures

CAAA Sections 172(c)(1) and (c)(2) require the District to demonstrate that it has adopted all 

control measures necessary to attain the 8-hour ozone standard as expeditiously as practicable and 

to meet RFP requirements. Reasonably available control measures (RACM) applies to both 

stationary source control measures and TCMs. The District has met this requirement for 

stationary sources through the Reasonably Available Control Technology (RACT) SIP presented 

in Section 3.1.5, the analyses of the revised control technique guidelines (CTG) presented in 

Section 3.1.6.1, and through a separate RACM analysis presented in Section 3.2.3. 

3.1.5. Reasonably Available Control Technology

CAAA Sections 182(b)(2) and 182(f) (42 U.S.C. §7511a) require ozone nonattainment areas to 

implement RACT for sources that are subject to CTG and for “major sources” of ROG and NOx, 

which are ozone precursors. RACT is the lowest emissions limitation that a particular source is 

capable of meeting by application of control technology that is reasonably available considering 

technological and economic feasibility (44 FR 53762; September 17, 1979). RACT requirements 

are included in the CAAA to assure that significant source categories at major sources of ozone 

precursor emissions are controlled to a “reasonable” extent, but not necessarily to the more 

stringent best available control technology (BACT), or maximum achievable control technology 

(MACT) levels, expected for new or modified existing major stationary sources. CTGs are EPA 

documents that define RACT for existing sources of air pollution. Emission sources covered by 

CTGs are termed CTG sources. 

3.1.6. RACT SIP

According to the EPA’s Final Rule to Implement the 8-Hour Ozone NAAQS (70 FR 71612; 

November 29, 2005), areas classified as moderate nonattainment or higher must submit a 

demonstration that their current rules fulfill 8-hour ozone RACT for all CTG categories and all 

major, non-CTG sources as a revision to their SIPs. RACT SIP submittals are in addition to the 

8-hour ozone attainment plans. The RACT SIPs were due to EPA by September 15, 2006. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 32 MAY 2008 

The District approved its RACT SIP on June 27, 2006 and sent it to ARB for submittal to EPA. 

ARB submitted the District’s RACT SIP to EPA on January 31, 2007. The RACT SIP found that 

all District rules that apply to ozone precursor emissions fulfill RACT requirements for the 8-hour 

ozone NAAQS. The rules meet RACT or, more commonly, exceed RACT because they comply 

with more current and stringent control requirements of the California Clean Air Act. The RACT 

SIP also found that all CTG sources and major non-CTG sources within District boundaries meet 

or exceed RACT. These findings are not surprising since Ventura County has had a very 

aggressive clean air program for many years. 

3.1.6.1. Updated CTGs

The CAAA requires the EPA to revise RACT, update existing CTG documents, or develop new 

documents, on a frequent basis to provide states and local clean air agencies with the most current 

technical information and assist them in determining RACT. In September 2006, the EPA 

updated the following CTGs: 

• Offset Lithographic and Letterpress Printing 

• Industrial Cleaning Solvents 

• Flexible Packaging Printing 

• Flat Wood Paneling Coatings 

District staff compared applicable District rules to the updated CTGs and concluded that the spray 

gun cleaning requirements in several District coating rules (Rules 74.12, 74.13, 74.18, 74.21, 

74.24, 74.30) may not meet the corresponding stringency requirements in the CTG for Industrial 

Cleaning Solvents. Likewise, the District may need to revise Rule 74.19, Graphic Arts, to meet 

the alcohol content limit for fountain solutions recommended in the CTG for Offset Lithographic 

and Letterpress Printing. However, Rule 74.19 does not specify an alcohol content limit for 

fountain solutions. Rather, it specifies an ROC content limit, which is not directly comparable to 

the CTG alcohol limit. Therefore, the District will evaluate and, if appropriate, revise its coating 

rules to address the Industrial Cleaning Solvents CTG regarding spray gun cleaning. The District 

will also evaluate District Rule 74.19 to address the Offset Lithography and Letterpress Printing 

CTG regarding the alcohol content of fountain solutions. Both of these rule evaluation 

commitments are reflected in Table 3-3, Further Study Control Measures. 

The District does not need to revise Rule 74.19 with respect to flexible packaging printing 

because it already meets the stringency recommendations of the Flexible Packaging Printing 

CTG. Additionally, the District does not have any flat wood paneling coating sources. 

3.1.7. New Source Review

NSR is a permitting program required by the CAAA to help ensure that new or modified 

equipment and facilities (e.g., boilers, turbines, crude oil storage tanks, power plants, and 

factories) do not significantly degrade air quality or slow progress towards clean air. NSR 

permits are legally binding documents that specify what can be constructed, what emission limits 

must be met, and how emission sources must be operated. The primary components of NSR are 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 33 

BACT and emission offsets. The District’s Engineering Division administers the District’s NSR 

program. Further information regarding NSR is available on EPA’s NSR website. Further 

information about the District’s air permitting program is available on the District’s Engineering 

Division website. 

BACT is an emission limitation based on the maximum degree of reduction for each regulated air 

pollutant emitted from, or resulting from, any new or modified stationary source. It is generally 

determined on a case-by-case basis, taking into account energy, environmental and economic 

impacts, and other costs. Emission reduction credits (ERCs) are banked emission reductions 

available to offset emission growth from new, replacement, modified or relocated emissions units. 

The District implements NSR through District Rule 26, New Source Review. Rule 26, which 

includes Rule 26 through 26.11, applies to new sources of air pollution and to modifications, 

replacements, and relocations of existing sources. The provisions of Rule 26 are applicable on a 

pollutant-by-pollutant and an emissions-unit-by-emissions-unit basis. 

Rule 26 requires that source owners and operators apply BACT to minimize air emissions from 

these sources. BACT is determined on a case-by-case basis by District staff during the permit 

approval process. Rule 26 also requires that certain emission increases be offset with emission 

decreases. However, it allows banking of certain emission decreases as ERCs for later use as 

offsets. 

3.1.8. Control Measures Not Retained in the 2007 AQMP

The 1994 AQMP contained stationary source control measures to help attain both the federal and 

state 1-hour ozone standards. This section presents stationary source control measures in the 

1994 AQMP but not retained in the 2007 AQMP. Table 3-4 lists these measures. In each case, 

the District has not adopted the measure as a District rule because the measure became obsolete or 

infeasible for Ventura County based on technological or economic considerations. Additionally, 

for the reasons given with each measure, no emission reductions would be lost by not retaining 

these measures in the 2007 AQMP. The following discussion includes a brief description of each 

measure and the reason for not retaining it in the 2007 AQMP. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 34 MAY 2008 

Table 3-4 

Control Measures Not Retained in the 2007 AQMP 

CM 

Number Control Measure Name Reason 

R-322 Painter Certification Program Proposed requirements included in District Rule 

74.2 – Architectural Coatings. 

R-327 Electronic Component Manufacturing Proposed requirements included in Rule 74.6 – 

Surface Cleaning & Degreasing. 

R-410 Marine Tanker Loading Marine tanker loading facilities no longer operate 

in the county. 

R-420 Pleasure Craft Fuel Transfer Infeasible due to technological and safety issues. 

R-421 Utility Engine Refueling 

Proposed requirements included in ARB’s 

Portable Fuel Container Spillage Control 

regulations. 

N/R-705 Low Emission Fleets 

Accomplished by District’s Carl Moyer Program

and ARB mobile source regulations and 

programs. 

R-322, Painter Certification Program: This control measure would have reduced ROG emissions 

from architectural, industrial, and maintenance coating operations by instituting a painter 

certification program to emphasize pollution prevention methods, techniques, and practices that 

minimize the amount of coatings and solvents used, transferred, disposed of, and wasted. 

This measure is now obsolete because District Rule 74.2, Architectural Coatings, is more 

cost-effective at reducing ROG emissions from architectural coating operations. Rule 74.2 was 

revised in 2001 to make the rule consistent with ARB’s SCM for Architectural Coatings. The 

estimated emission reductions from the Rule 74.2 revision are 0.53 tons per day of ROC. This 

amount is about the same as from R-322. Hence, no emission reductions would be lost by not 

retaining R-322. Moreover, no other air district in California has proposed or implemented such a 

program. 

R-327, Electronic Component Manufacturing: This control measure would have reduced ROG 

emissions from electronic component manufacturing through several control methods. These 

control methods included zero- or low-ROG solvents, improved operating procedures, and add-on 

emission control equipment. 

This control measure is obsolete because its proposed requirements have been included in District 

Rule 74.6, Surface Cleaning & Degreasing. Hence, no potential emission reductions would be 

lost by not retaining R-327. 

R-410, Marine Tanker Loading: District staff developed this control measure based on the 

ARB’s BARCT determination for Marine Tanker Loading Operations. The measure would have 

reduced ROG emissions from marine tanker loading operations by requiring use of vapor 

collection systems during loading of petroleum products into marine tankers. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 35 

This measure is obsolete because Ventura County no longer has any marine tanker loading 

facilities. The marine tanker loading facilities that were in the county ceased operating in the 

1990s, have been dismantled, and no longer have District air permits. Moreover, any new marine 

tanker facilities would be subject to the District’s NSR rule and would have to install BACT to 

control ROG emissions during loading or unloading operations. No new marine tanker loading 

facilities in the county are anticipated at this time. Therefore, no emissions reductions would be 

lost by not retaining R-410. 

R-420, Pleasure Craft Fuel Transfer: This control measure would have reduced ROG emissions 

from pleasure craft fueling operations through a new District rule to require Phase-II vapor 

recovery systems on facilities that refuel pleasure craft. The District is not retaining this measure 

in the 2007 AQMP because ARB has included the measure (FVR-2, Recover Fuel Vapors from 

Gasoline Dispensing at Marinas) in its 2003 Statewide Strategy and no emissions would be lost 

by not retaining R-420. 

R-421, Utility Engine Refueling Operations: This control measure would have reduced ROG 

emissions from gasoline-powered utility equipment and motor vehicles refueling from portable 

fuel containers (gasoline cans). The measure called for all portable fuel containers sold or used in 

Ventura County to have spill control devices, such as leakless spouts, that prevent gasoline flow 

before the spouts are inserted into fuel tanks and after they are withdrawn from the tanks. In 

addition, fuel flow stops when the tanks become full, thus eliminating overfilling and spillage. 

This measure is now obsolete because ARB is regulating portable fuel containers. The 

regulations include requirements such as spill-proof spouts, low permeation container walls, and 

labeling requirements. Therefore, no emissions would be lost by not retaining R-421. 

R-705/N-705, Low-Emission Vehicle Fleets: This measure proposed to control ROG and NOX

emissions from public and private vehicle fleets. Fleet operators with vehicle fleets based in 

Ventura County would have been required to allocate a portion of their new fleet vehicle 

purchases to the purchase of low-emission vehicles. The measure would have applied to light-, 

medium-, and heavy-duty centrally-fueled fleets with more than a specified number of vehicles 

and would have gone beyond existing ARB programs. 

This measure is not retained in the 2007 AQMP because the same amount of emission reductions 

are being achieved through the District’s Carl Moyer Memorial Air Quality Standards Attainment 

Program and various ARB’s motor vehicle emission standards and clean fuel fleet rules, such as 

the Fleet Rule for Transit Agencies - Urban Bus Program, Solid Waste Collection Vehicle Rule, 

and Rule for On-Road Heavy-Duty Diesel-Fueled Public and Utility Fleets. In addition, ARB is 

proposing new, more effective motor vehicle regulations that will further reduce ROG and NOx

emissions in Ventura County. Therefore, a separate local low-emission fleet rule is not necessary 

and would not reduce motor vehicle emissions in Ventura County beyond what ARB’s 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 36 MAY 2008 

regulations and programs have achieved and will achieve. There are also legal issues regarding 

whether the District can regulate private motor vehicle fleets. Hence, no potential emission 

reductions would be lost by not retaining R-705/N-705. 

3.2. Transportation Control Measures 

TCMs are strategies that reduce motor vehicle emissions by reducing vehicle trips, vehicle use, 

vehicle miles traveled (VMT), vehicle idling, and traffic congestion. The CAAA requires TCMs, 

to meet progress milestones and demonstrate attainment of national air quality standards. The 

following strategies reduce emissions from on-road motor vehicles. These strategies were also in 

the 1994 AQMP. 

Trip Elimination: This strategy reduces vehicle emissions by eliminating vehicle trips. The 

primary emissions eliminated are the cold-start emissions that occur when vehicle engines have 

been at rest for a period and then restarted. Cold-start emissions occur after engine startup but 

before the engines are warm enough for the emission control systems to work effectively. 

Cold-start emissions are a large percentage of total vehicle emissions and thus a major source of 

ozone precursors. Telecommuting, carpooling, combining trips, flexible work schedules, and 

certain land use measures that provide housing near jobs and shopping centers are strategies that 

eliminate vehicle trips. 

Vehicle Substitution: This strategy reduces emissions associated with motor vehicle use by using 

nonmotorized transportation modes, which do not produce air emissions. Walking, biking, and 

telecommuting are all examples of vehicle substitution. Adopting trip reduction ordinances is a 

mechanism to encourage walking or biking facilities and discourage motor vehicle use in highly 

congested areas. 

Vehicle Miles Traveled Reduction: This strategy reduces motor vehicle emissions because 

vehicles traveling fewer miles produce fewer emissions. This strategy does not reduce cold-start 

emissions. Park-and-ride lots, carpooling, and land use measures are all ways to reduce trip 

distances and, therefore, vehicle miles traveled and vehicle emissions. 

Vehicle Occupancy: Increasing the number of passengers per vehicle can reduce all emissions 

associated with motor vehicle use. Transit, carpools, and vanpools are all mechanisms to 

implement this strategy. Other mechanisms include providing ridematch services for carpools 

and vanpools, restricting or limiting roads for high occupancy vehicles and passenger buses, 

establishing employer-based transportation management programs that encourage carpooling, 

vanpooling and transit use among employees. 

Technological Improvements: This strategy reduces emissions through technological 

improvements to the internal operation of motor vehicles and the technologies used to improve 

the performance of transportation systems. Clean-fuel/electric vehicles, vehicle emission 

controls, Intelligent Transportation Systems, signal synchronization and freeway management 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 37 

systems that improve the performance of transportation systems are all mechanisms to implement 

this strategy. Programs to control extended idling of vehicles and remove older, high-polluting 

vehicles through vehicle scrapping incentives reduce emissions as well. 

3.2.1. Transportation Control Measures Categories and Projects

This section presents the transportation control measures (TCMs) in the 2007 AQMP. The TCMs 

are grouped by categories and projects under control measure R-700/N-700, Transportation 

Control Measures, an umbrella control measure retained from the 1994 AQMP. To be included 

in the AQMP, potential projects must be TCMs in SCAG’s Regional Transportation Plan (RTP) 

and Regional Transportation Improvement Program (RTIP). 

Candidate projects are first screened by District, Ventura County Transportation Commission 

(VCTC), and SCAG staff to determine if they are TCMs as defined by the project categories 

listed in Table 3-5. SCAG’s Transportation Conformity Working Group, the local agency for the 

interagency consultation process required by the federal transportation conformity regulation, 

then formally confirms the projects as TCMs eligible for inclusion in the RTP and RTIP. The 

interagency consultation process is part of the federal transportation conformity regulation that 

requires procedures for federal, state, and local air districts and transportation agencies to consult 

with each other on transportation plans, programs, and projects. Transportation conformity is a 

regulatory process to help ensure that transportation plans, programs, and projects are consistent 

with air quality goals. District Rule 221, Transportation Conformity, contains a memorandum of 

understanding that outlines the interagency consultation process. Further information regarding 

transportation conformity is presented in Section 3.3 below. 

The RTP is a long-range regional plan (minimum 20-years) that provides a blueprint for future 

transportation improvements and investments based on specific transportation goals, objectives, 

policies, and strategies. RTPs, based on federal transportation law, identify strategies to meet 

mobility, financial and air quality requirements. RTIPs are short-term transportation programs, 

with a six-year planning horizon, that identify specific transportation projects to implement the 

RTPs. SCAG is the Metropolitan Planning Organization responsible for updating the RTP and 

RTIP every four and two years, respectively, for the six-county SCAG region, including Ventura 

County. Both the RTP and RTIP for the SCAG region are on SCAG’s RTP and RTIP websites. 

The 2008 RTP is SCAG’s multi-modal plan for a better regional transportation system, integrated 

with the best possible growth pattern for the region out to 2035. The plan provides the basic 

policy and program framework for long-term investment in the region’s vast transportation 

system in a coordinated, cooperative, and continuous manner. Transportation investments in the 

SCAG region that receive state or federal transportation funds must be consistent with the RTP 

and must be included in the RTIP when ready for funding. SCAG’s 2008 RTP provides the basis 

for the transportation control strategy of the 2007 AQMP and includes the total regional emission 

reductions from transportation projects in Ventura County. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 38 MAY 2008 

Table 3-5 

TCM Project Categories Included in R-700/N-700 

Project Category 

A. Ridesharing Measures 

Carpooling, Vanpooling, Park and Ride Lots, Ride Matching Services, Incentive Programs, Satellite 

Work Centers, Guaranteed Ride Home Programs, Station Cars, Onsite Services 

B. Non-Motorized Measures 

Bicycle Paths/Facilities, Pedestrian Paths/Facilities, Telecommuting, Flexible Work Schedules, 

Bicycle and Pedestrian Programs 

C. Traffic Flow Improvement Measures 

Signal Synchronization, Intersection Improvements, Incentive/Disincentive Programs, High 

Occupancy Vehicle Lanes, Intelligent Transportation Systems, Ramp Metering 

D. Land Use Measures 

Transportation Demand Management (TDM) Ordinances, Smart Growth/Sustainable Community 

Projects, Mixed Use Development, Parking Management and Standards, Congestion Management 

Plan, TDM Strategies 

E. Transit Measures 

Bus Fleet Expansion, Shuttles and Paratransit Vehicles Expansion, Transit Stations and Facilities, 

Express Busways, Passenger Rail Service, Rail Stations and Facilities, Real-Time Transit 

Information Systems, Transit Subsidies 

The RTIP includes emission reductions from TCM projects. The emission reductions from TCMs 

are a subset of the total regional emission reductions from the RTP. The AQMP enforceable 

commitments for TCMs are to fund and implement the TCM projects contained in the first two 

years of the current six-year RTIP. Moreover, to be eligible for federal funding, the EPA’s 

conformity rule requires that all TCMs in clean air plans undergo a timely implementation 

analysis in each RTIP update. The timely implementation requirement assures that TCMs receive 

priority funding and are implemented on schedule. 

The RTIP update contains a timely implementation report, which tracks each committed TCM 

and demonstrates timely implementation. Appendix A presents the current list of committed 

TCMs in the 2006 RTIP. 

3.2.2. TCM Rollover and Substitution

SCAG is responsible for updating the RTIP every two years. At each RTIP update, a new list of 

TCMs from the first two years of the RTIP, plus continuing TCMs from the previous RTIP, are 

rolled over into the AQMP upon approval by ARB and EPA. This “rollover” list becomes the 

committed TCMs for timely implementation and is monitored for compliance with the schedule 

established in the new RTIP. Once a TCM project is completed, it is reported in the RTIP update 

as completed and removed from future RTIPs. An RTIP update can occur more frequently than 

the biennial update. The rollover process applies when the RTIP requires a conformity analysis 

and finding. 

A TCM substitution is required when a committed TCM project cannot be delivered or will be 

significantly delayed. The VCTC and/or the project sponsor must notify SCAG of the problem 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 39 

and propose a substitute TCM project or group of projects. The TCM substitution must follow 

the process set forth in Section 6011(d) of the federal SAFETEA-LU (Safe, Accountable, 

Flexible, Efficient Transportation Equity Act: A Legacy for Users) legislation and the federal 

transportation conformity rule. The substitute project(s) may not be from the committed TCM 

list. 

3.2.3. Reasonably Available Control Measures - TCMs

The Clean Air Act requires a review of RACM for TCMs during AQMP development. For 

TCMs to be RACM, TCMs must be both technically and economically feasible and must advance 

the projected attainment date of the air quality standard by at least one year. EPA left the 

definitions for technically and economically feasibility vague so that areas could determine what 

measures would be feasible or infeasible according to local factors. Factors, such as the 

availability of control measures, ability to achieve emission reductions, and degree of cost 

effectiveness, are the primary considerations on an area-by-area basis. In addition, EPA did not 

provide a conclusive definition on “advancing attainment,” but agencies have based their 

determination of RACM on whether a measure or group of measures would advance attainment by 

at least one year. 

A list of candidate RACMs was prepared by SCAG and the District using TCMs from CAAA 

Section 108(f)(1)(A) and other Metropolitan Planning Organizations and air districts. The TCMs 

are organized according to the sixteen TCM categories listed in CAAA Section 108(f). Each 

candidate TCM has a control measure number, title, and a brief description. The District, along 

with SCAG and VCTC staff conducted the RACM analysis. If a TCM was found feasible for 

Ventura County, it was recommended as a potential measure for the 2007 AQMP with the 

appropriate implementing agency listed. If a TCM was determined infeasible for Ventura 

County, it was not recommended as a measure for the 2007 AQMP and the reasoned justification 

was provided. Appendix B is the RACM analysis conducted for the 2007 AQMP. 

The RACM analysis was listed on the District’s website and reviewed by the Transportation 

Conformity Working Group, Technical Transportation Advisory Committee, and Transit 

Operators Committee. Based on this comprehensive analysis, the majority of TCMs determined 

to be feasible are either being implemented, or have been implemented, in Ventura County. The 

TCMs determined to be infeasible did not meet the criteria for RACM because of the individual 

reasons provided in the analysis. Moreover, implementing all feasible TCMs in the RACM 

analysis would not advance the county’s 8-hour ozone attainment date by at least one year. This 

criterion also applies to RACM implementation. 

3.2.4. Motor Vehicle Trips and VMT vs. On-Road Motor Vehicle Emissions

Section 182(d)(1)(A) of the CAAA required that by November 15, 1992 the District submit 

specific enforceable TCMs and strategies to offset any growth in emissions from growth in VMT 

or number of vehicle trips, sufficient to allow total district-wide emissions to comply with the 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 40 MAY 2008 

reasonable further progress and attainment requirements. The District met that requirement and 

showed that countywide motor vehicle emissions were decreasing despite increasing VMT. The 

2007 AQMP updates that demonstration as shown by the trend projections in Figure 3-1. The 

dramatic downward trend in motor vehicle emissions is due largely to California’s comprehensive 

motor vehicle emissions regulations. 

Figure 3-1 

Trips and VMT vs. On-Road Motor Vehicle Emissions Trends 

0

10,000

20,000

30,000

40,000

50,000

60,000

2000

2002

2004

2006

2008

2010

2012

2014

0

5

10

15

20

25

30

35

On-Road Motor Vehicle Emissions

Tons/Day

VMT (x1000)

Trips (x100)

ROG

NOx

NOTES: 

EMFAC2007v2.3, Nov. 1, 2006**WIS Enabled. 

Run Date: 03/12/2008 10:47:42. 

Season: Summer. 

See Table 4-2 for underlying data. 

3.3. Conformity 

Conformity is a federal regulatory process required in nonattainment areas by CAAA Section 

176(c) to ensure that federal funding and approvals will not cause new air quality violations, 

worsen existing violations, or delay timely attainment of the NAAQS. Section 176(c) prohibits 

federal agencies, departments, or instrumentalities from engaging in, supporting, providing 

financial assistance for, licensing, permitting or approving any action which does not conform to 

an approved state or federal clean air plan. It is called conformity because federal agencies, such 

as the Federal Highway Administration (FHWA), Federal Transit Administration (FTA), and 

Federal Aviation Administration (FAA), must show that their actions “conform with” (i.e., do not 

undermine or hinder) approved SIPs. 

A conformity determination is a formal demonstration that the subject federal action is consistent 

with the respective SIP. Federal agencies make such demonstrations by performing conformity 

reviews of proposed federal actions. The conformity review evaluates and documents 

project-related air pollutant emissions, local air quality impacts, and the potential need for 

emission mitigation. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 41 

In 1993, EPA promulgated two sets of conformity regulations to implement Section 176(c): 1) 

transportation conformity; and, 2) general conformity. Transportation conformity is applicable to 

highway and mass transit projects and to transportation plans, programs, and projects funded 

under the Federal Highway and Transit Act. General conformity is applicable to other federal 

actions and approvals such as for new airports and water treatment facilities. The District 

currently has two conformity rules, Rule 221, Transportation Conformity; and, Rule 220, General 

Conformity. 

3.3.1. Transportation Conformity

Transportation conformity is a CAAA and SAFETEA-LU regulatory process that coordinates air 

quality planning and transportation planning to help ensure that highway and transit projects will 

not cause new air quality violations, worsen existing violations, or delay timely attainment of the 

NAAQS. Conformity applies to transportation improvement programs, transportation plans, and 

highway and transit projects funded or approved by the FHWA and the FTA. Both the RTP and 

RTIP must demonstrate conformity with the clean air plans within the SCAG region. 

Metropolitan planning organizations, such as SCAG, make initial conformity determinations in 

metropolitan areas, while state departments of transportation usually do so in areas outside 

metropolitan areas. FHWA and FTA must also make conformity determinations. EPA and the 

Federal Highway Administration websites contain further information regarding transportation 

conformity. 

Central to transportation conformity are motor vehicle emissions budgets (also referred to as 

conformity budgets), which set the maximum amount of on-road mobile source emissions that 

nonattainment areas can produce and continue to demonstrate progress towards attainment. 

Conformity budgets therefore act as “ceilings” for future on-road mobile source emissions. 

Exceedances of a conformity budget in a nonattainment area indicate an inconsistency with the 

applicable SIP and thus could jeopardize federal funding for transportation projects in that area. 

The conformity budget for an area is based on projections of motor vehicle emissions, and reflects 

the emission benefits of transportation control measures included in the SIP. Motor vehicle 

emissions are based upon the number of vehicles in the region, vehicle mileage, the rate of fleet 

turnover, seasonal temperatures in the region, vehicle miles traveled, population growth, and 

other factors. 

Normally, conformity budgets are set with RFP Plans. However, EPA is revising its RFP 

regulations for areas whose air quality is dominated by air pollution transported from upwind 

regions. Ventura County is one of those areas. Until those revisions are complete, EPA will not 

approve conformity budgets for such areas (see Chapter 5). Therefore, to not disrupt Ventura 

County’s transportation planning process, nor jeopardize the county’s federal transportation 

funding, ARB has prepared an Early Progress Plan (EPP) for the county for the sole purpose of 

establishing a transportation conformity budget (13 tpd ROG & 19 tpd NOx) for 2009, Ventura 

County’s attainment year as a moderate 8-hour ozone nonattainment area. Ventura County’s EPP 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 42 MAY 2008 

and 2009 conformity budget can be found at ARB’s California State Implementation Plan

website. 

On April 16, 2008, EPA found that the motor vehicle emissions budgets contained in Ventura 

County’s EPP adequate for transportation conformity decisions. Consistent with the 2004 final 

amendments to the Transportation Conformity Rule (69 FR 4004), the EPP 8-hour ozone 

conformity budgets replace the existing 1-hour ozone conformity budgets in the 2004 AQMP. As 

a result, SCAG and the U.S. Department of Transportation must use these budgets in future 

conformity analyses in Ventura County. 

Notwithstanding the 2009 transportation conformity budget established by the EPP, the 2007 

AQMP includes the following conformity budget for Ventura County as a serious 8-hour ozone 

nonattainment area. Table 3-6 presents a summary of the motor vehicle emissions budget for 

transportation conformity purposes under a serious federal 8-hour ozone classification. Once 

EPA approves the budget, it will supersede the EPP’s conformity budget and serve as the 

conformity emissions budget for future transportation conformity determinations in Ventura 

County. 

Table 3-6 

Motor Vehicle Emissions Budget 

(tons per day) 

 2008 2011 2012 

ROG 13 11 9 

NOx 20 16 13 

NOTES:

Based on EMFAC2007 and reductions from adopted rules not in EMFAC2007. 

Budgets obtained by rounding up to the nearest ton. 

3.3.2. General Conformity

General conformity is a CAAA regulatory process that applies to most federal actions other than 

transportation actions. Federal actions subject to general conformity include issuance of Army 

Corps of Engineers permits, water and wastewater projects funded by EPA, and other federal 

projects, such as harbors, airports, and reservoirs. Certain federal projects are exempt from 

general conformity. Those include projects whose air pollutant emissions would be below 

specified de minimis emission levels (based on area nonattainment classifications), and certain 

projects presumed to conform, such general and routine maintenance activities, activities at 

Superfund sites, and activities conducted in response to national emergencies. In addition, 

activities in attainment areas are not generally subject to general conformity, unless the area was a 

nonattainment area and is now under a federal clean air maintenance plan. The federal agency 

that approves the project or activity is responsible for the making the conformity determination 

for the project. EPA’s General Conformity website contains further information regarding 

general conformity. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 43 

3.4. Incentive Programs 

The District participates in four clean air incentive programs to help Ventura County meet state 

and federal clean air standards: the Clean Air Fund, the Carl Moyer Memorial Air Quality 

Standards Attainment Program, the Lower Emissions School Bus Program, and the Lawn Mower 

Trade-In Program. Below are summaries of these programs. Further information regarding the 

District’s clean air incentive programs is available on the District’s Grants/Incentive Programs

website. 

3.4.1. Clean Air Fund

The 3M Company created the Clean Air Fund in Ventura County in 1991 with a $1.5 million 

donation. Three hundred thousand dollars of that amount was set aside as a permanent 

endowment, which is now more than $823,000. The nonprofit Ventura County Community 

Foundation holds the funds in a trust. The Ventura County Air Pollution Control Board oversees 

the Clean Air Fund and authorizes project funding. The Clean Air Fund Advisory Committee 

(Committee) reviews all grant proposals and makes recommendations for funding to the Air 

Pollution Control Board. The Committee is comprised of representatives from transportation, 

environmental, business, and citizen interest groups. 

Since its inception, the Clean Air Fund has allocated over $1.7 million for 48 clean air projects of 

various types. Examples of funded projects include clean air educational programs, solar pool 

heaters for local schools, cleaner boat engines, a lawn mower exchange program, and compressed 

natural gas transit buses and trash trucks. 

3.4.2. Moyer Memorial Air Quality Standards Attainment Program

The California State Legislature created the Carl Moyer Program in 1998, named after the late 

Dr. Carl Moyer to recognize his work in the air quality field and his efforts to develop this 

important program. The Carl Moyer Program provides grants to owners of heavy-duty diesel 

vehicles, vessels, locomotives, and/or stationary agricultural pumps to replace, repower, or 

retrofit heavy-duty diesel engines to reduce NOx, ROG, and particulate matter. The Carl Moyer 

Program complements California’s regulatory clean air program by obtaining early or extra 

emission reductions to help meet state and federal clean air standards. Carl Moyer Program

grants are available to both private companies and public agencies. 

The Carl Moyer Program is a cooperative effort of the ARB and local air pollution agencies. 

Each year, the ARB awards grants to local air agencies that apply for funds for local Carl Moyer 

Programs. In turn, air districts, following guidelines adopted by ARB, provide grants to public 

and private entities for cleaner-than-required engines and equipment. ARB’s Carl Moyer 

Program requires, in part, that funded projects in Ventura County operate for at least three years 

and 75 percent of their use be within the county. In addition, to qualify for funding, projects must 

meet cost effectiveness requirements. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 44 MAY 2008 

The District has operated its Carl Moyer Program since 1998. To date, nearly $10 million in 

Carl Moyer Program funds have been obligated locally. To help this effort, the District has 

provided $3.5 million in matching funds. The District’s Carl Moyer Program has mostly funded 

new alternative fuel heavy-duty trucks, cleaner marine vessel engines, construction equipment 

engines, and agricultural irrigation pump engines.

In 2007, the District’s board approved Carl Moyer Program funding to help repower 58 

agricultural pump engines, 15 boat propulsion engines, 8 boat auxiliary engines, and 9 pieces of 

mobile farm equipment, all with new lower-emission diesel engines. The total amount of the 

grants was over $2.35 million. The anticipated emission reductions from these projects are 61.8 

tons per year of NOx, 9.1 tons per year of ROG, and 1.7 tons per year of PM. 

Through February 2008, the District’s board approved Carl Moyer Program funding to repower 

an additional 18 agricultural pump engines with new lower-emission diesel engines. The total 

amount of the grants was over $238,000. The anticipated emission reductions from these projects 

are 15.6 tons per year of NOx, 2.6 tons per year of ROG, and 0.8 tons per year of PM. 

ARB projects that Carl Moyer projects will reduce future ROG and NOx emissions in Ventura 

County by 0.01 and 0.19 tons per day, respectively in 2012. Table 4-3 presents projected 

Carl Moyer ROG and NOx emission reductions for each milestone year. 

3.4.3. Lower-Emission School Bus Program

The ARB adopted the Lower-Emission School Bus Program in December 2000. This incentive 

program reduces schoolchildren’s exposure to both toxic particulate emissions and smog-forming 

NOx emissions through two program components: the Lower-Emission School Bus Replacement 

Program, and the School Bus Retrofit Program. The Lower-Emission School Bus Replacement 

Program replaces older, in-use, high-polluting diesel school buses with new lower-emission 

buses. The School Bus Retrofit Program reduces particulate matter emissions from diesel school 

buses by retrofitting the bus engines with particulate traps. The District participates in both 

programs. These programs offer the District a unique opportunity to work with the school 

districts in the county in joint efforts to reduce children’s exposure to diesel exhaust, which is a 

toxic air contaminant and a human carcinogen. 

The Lower-Emission School Bus Replacement Program enables local school districts to replace 

pre-1987 model year buses with either new cleaner compressed natural gas (CNG) buses or new 

lower-emission diesel buses. Eligible school districts must contribute $25,000 to replace an 

in-use, 1977 through 1986 model year school bus, and no cost to replace an in-use, pre-1977 

model year school bus. The program pays the remainder. School districts that purchase CNG 

buses can obtain an additional 10 percent of their grant for CNG refueling facilities.

The program’s main goal is replacement of pre-1977 model year school buses. Therefore, the 

District’s program focuses on replacing pre-1977 buses over other school bus replacement 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 45 

projects. Another goal of the program is to award two-thirds of the grants for CNG-fueled buses 

and one-third for lower emission diesel buses. The District’s program thus gives priority to 

school districts applying for CNG-fueled buses. The District’s program also requires that 

replaced buses be destroyed so that they can no longer operate in the county or elsewhere. To 

date, 20 CNG school buses and 9 lower-emission diesel school buses have replaced 29 pre-1987 

school buses. 

The School Bus Retrofit Program provides funding to school districts to retrofit existing diesel 

school buses with particulate filters that reduce diesel particulate emissions by at least 85 percent, 

thereby lessening peoples’ exposure to harmful diesel exhaust. Participating local air districts 

administer the program with oversight by ARB. School district participation is voluntary and the 

grant monies fully fund the cost and installation of the new filters. No matching funds are 

required of either the District or the school districts. 

In 2001, ARB granted the District $290,000 to retrofit 80 diesel school buses with diesel 

oxidation catalysts and Spiracle crankcase vent filter units. The combination of the diesel 

oxidation catalyst and Spiracle crankcase vent filter reduces particulate emissions by over fifty 

percent. Ten county school districts participated in the retrofit program. In 2005, ARB granted 

the District $273,000 to retrofit 33 diesel-powered school buses with diesel particulate filters 

(traps). 

Proposition 1B, the Highway Safety, Traffic Reduction, Air Quality, and Port Security Bond Act 

of 2006, will provide $200 million for the School Bus Replacement and Retrofit Programs

statewide. Ventura County’s share of this funding will be approximately $5 million. 

3.4.4. Electric Lawn Mower Trade-In Rebate Program

The Ventura County APCD Lawn Mower Trade-In Rebate Program reduces combustion and 

gasoline spillage emissions from gasoline-powered lawn mowers by replacing gasoline-powered 

lawn mowers with electric lawn mowers. One hour of lawn mowing using a pre-2005 gasoline 

mower emits as much ROG and NOx as a super ultra low emission vehicle driving 792 miles or 

13 conventional automobiles driving 60 mph for one hour. 

In 1999 and 2000, the District conducted two electric mower buy down/exchange program events 

(Project Clean Cut in 1999 and 2000) at the Ventura Home and Garden Show. Although 

successful, both of these weekend events were very staff intensive, and required considerable 

resources to advertise, coordinate, and handle the event logistics. 

At the 1999 event, 219 gasoline-powered lawn mowers were exchanged, and at the 2000 event, 

198 gasoline-powered lawn mowers were exchanged. To make these three-day events successful, 

large advertising campaigns were required at significant cost. To minimize advertising and 

administrative costs, District staff developed the 2006 Lawn Mower Trade-In Rebate Program, 

which is a year-round promotion rather than a single weekend event. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

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The District commenced its 2006 Lawn Mower Trade-In Rebate Program in June 2006 with a 

$65,000 grant from the Clean Air Fund. The program exchanged 121 gasoline-powered mowers 

with new electric lawn mowers and 199 commercial leaf blowers with new low-emission leaf 

blowers. 

The District’s board approved the 2008 Lawn Mower Trade-In Rebate Program in February 

2008. The 2008 program is a partnership with Lowe’s Home Improvement stores in Ventura and 

Simi Valley, and with Country Home Products, maker of the Neuton cordless lawn mower. Total 

program funding is $82,000. Of that amount, $50,000 was an ARB grant and $32,000 was left 

over from 2006 program funds. 

The 2008 program is open to all county residents and provides participants with either $200 

vouchers to purchase cordless electric lawn mowers or $129 vouchers to purchase corded, plug-in 

electric lawn mowers. The $200 rebate is based on a similar rebate offered by the South Coast 

AQMD. The 2008 program will end when all designated funds are disbursed. 

3.5. Ventura County Smart Growth Policies and Programs 

Ventura County has been a leader in controlling urban growth and sprawl for decades. As a 

result, Ventura County cities are distinct from each other geographically, with greenbelt buffers 

and agricultural land separating the urbanized areas of the county. Moreover, 90 percent of the 

county’s population lives within the county’s ten cities. Ventura County has successfully 

accommodated growth while remaining a leading agricultural area in California. Some of the 

notable urban growth guidelines, policies, and programs in Ventura County are summarized 

below for informational purposes. 

Guidelines for Orderly Development

The Guidelines for Orderly Development help facilitate orderly development of Ventura County 

by directing urban development to the cities rather than to the county’s unincorporated areas. The 

Guidelines for Orderly Development’s primary policy states: “Urban development should occur, 

whenever and wherever practical, within incorporated cities which exist to provide a full range of 

municipal services and are responsible for urban land use planning.” Ventura County’s Local 

Agency Formation Commission (LAFCO) administers the Guidelines for Orderly Development. 

The County of Ventura, all ten cities in the county, and the LAFCO have adopted the Guidelines 

for Orderly Development as policy. The County of Ventura first adopted the Guidelines for 

Orderly Development in 1969 and revised them in 1996. The Guidelines for Orderly 

Development: 

• Provide a framework for cooperative intergovernmental relations. 

• Allow for urbanization in a manner that will accommodate the development goals of the 

individual communities while conserving the resources of the County. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 47 

• Promote efficient and effective delivery of community services for existing and future 

residents. 

• Identify in a manner understandable to the public the planning and service responsibilities 

of local governments providing urban services. 

Greenbelt Agreements

Greenbelt Agreements (Agreements) are policy statements adopted by resolution or ordinance 

between the County of Ventura and one or more of the county’s ten cities. Greenbelts in Ventura 

County are areas where cities have agreed not to annex areas and the County of Ventura has 

pledged to permit only open space or agricultural uses. The Agreements protect open space and 

agricultural lands from urbanization by preventing premature conversion to agriculturally 

incompatible uses. The Agreements also help ensure that the cities do not sprawl into each other. 

Although not a party to the Agreements, the Ventura County LAFCO will not approve a 

development that conflicts with any greenbelt agreement unless exceptional circumstances exist. 

City and County elected officials in Ventura County were pioneers in designing and adopting 

greenbelts. There are seven greenbelt agreements in Ventura County: 

• Ventura-Santa Paula Greenbelt 

• Santa Paula-Fillmore Greenbelt 

• Camarillo-Oxnard Greenbelt 

• Santa Rosa Valley Greenbelt 

• Tierra Rejada Greenbelt 

• Ventura-Oxnard Greenbelt 

• Fillmore-Piru Greenbelt 

SOAR and CURB

The Save Open Space and Agricultural Resources (SOAR) and City Urban Restriction Boundary 

(CURBs) resulted from several voter-approved ballot initiatives in the unincorporated areas of 

Ventura County and eight of the county’s ten cities. The SOAR initiatives require voter approval 

in the affected jurisdictions before specified General Plan land use designations, such as 

agriculture and open space, can be up-zoned to urban designations. The CURB initiatives define 

a boundary around the affected jurisdictions and require voter approval before urban development 

can occur outside the CURB lines. The SOAR and CURB measures work together to direct urban 

growth to within existing city boundaries, thereby restricting urban sprawl, encouraging infill and 

higher density development, and protecting agricultural, open space, and natural lands in Ventura 

County. 

The city SOARs established CURBs around each city. With limited exceptions, development 

beyond a city’s CURB cannot occur unless the city voters approve an extension of the CURB. 

The city CURBs complement the County SOAR by preventing annexations of adjacent 

unincorporated areas into the cities for development unless the voters approve such annexations. 

The following are the Ventura County jurisdictions covered by SOAR initiatives: 
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• County of Ventura 

• City of Ventura 

• City of Camarillo 

• City of Thousand Oaks 

• City of Simi Valley 

• City of Oxnard 

• City of Moorpark 

• City of Santa Paula 

• City of Fillmore 

Ventura County Air Quality Assessment Guidelines

The Ventura County Air Quality Assessment Guidelines (Guidelines) is a District document that 

provides District staff, lead agencies, consultants, and project applicants with uniform procedures 

for preparing the air quality sections of environmental documents pursuant to the California 

Environmental Quality Act (CEQA). CEQA applies to all discretionary activities, both public 

and private, approved by California public agencies, unless an exemption applies, and requires 

that any significant environmental effects of such projects be mitigated to the extent feasible. 

CEQA thereby provides a mechanism to reduce air emissions associated with urban growth. 

The Guidelines recommend specific criteria and threshold levels for determining whether a 

proposed project may have a significant adverse impact on air quality. The Guidelines also 

provide mitigation measures to lessen or eliminate project air quality impacts found to be 

significant. The District does not require that lead agencies use the Guidelines; however, most 

lead agencies in the county, including the ten cities and the County of Ventura, do. Additionally, 

District staff routinely reviews and comments on the air quality sections of environmental 

documents prepared by county lead agencies.

Resolutions of Commitment to Implement Reasonably Available Transportation Control 

Measures

The commitments the ten cities and the County of Ventura made to integrate transportation, land 

use, and air quality considerations into land use decisions are documented in Appendix C-91, 

Resolutions of Commitment to Implement Reasonably Available Transportation Control 

Measures, of the 1991 AQMP. Additionally, several of the cities and the County of Ventura have 

incorporated air quality goals and policies into their General Plans. 

Smart Growth in Ventura County

Smart growth is a set of urban planning and transportation concepts that concentrate growth to 

enhance a community’s vitality and livability, avoid urban sprawl, preserve open space and 

agricultural land, and protect the environment. Smart growth advocates compact, transit-oriented, 

walkable, and bicycle-friendly land use, including mixed-use development, with a range of 

housing choices for all income levels. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 49 

Several jurisdictions in Ventura County are pursuing smart growth development on large and 

small scales. Notable examples include the Cities of Ventura and Fillmore and the County of 

Ventura. The City of Ventura has embraced smart growth as a central element of its 2005 

General Plan. Detailed information regarding the City of Ventura’s smart growth efforts and its 

2005 General Plan can be found on the city’s Community Development Department and General 

Plan websites. The City of Fillmore, through its Downtown Specific Plan, is redeveloping its 

central downtown area into an exemplary model of urban mixed-use development. The County of 

Ventura’s Build It Smart website, which promotes energy- and resource-efficient building 

practices and land use decisions in Ventura County, profiles the City of Fillmore’s Downtown 

Specific Plan. The County of Ventura is pursuing smart growth development solutions for the 

small rural community of Piru. The Piru development initiative is outlined in the County of 

Ventura’s Piru SCAG Smart Growth Study. 

3.6. State Strategy 

On September 27, 2007, the ARB adopted its State Strategy for California’s 2007 State 

Implementation Plan to achieve the additional emission reductions needed for all areas of the 

state, including Ventura County, to attain both the federal 8-hour ozone and PM2.5 standards. 

Ventura County is nonattainment only for the federal 8-hour ozone standard. Those areas with 

the most challenging air quality problems – the South Coast AQMD, and San Joaquin Valley 

Unified APCD – are driving ARB’s State Strategy. ARB and EPA will implement the State 

Strategy measures. The District will not implement any of the State Strategy measures because 

they are not under District regulatory authority. However, the 2007 AQMP incorporates the 

measures by reference and reflects the emission reductions the measures will achieve in Ventura 

County. 

The control measures in ARB’s State Strategy target passenger vehicles, trucks, construction 

equipment, agricultural equipment, goods movement, fuels, recreational vehicles and boats, and 

pesticides. Table 3-7 presents the State Strategy control measures, along with expected 2012 

emission reductions in Ventura County. 

Appendix H of ARB’s State Strategy addresses ROG emission reductions from pesticide usage in 

Ventura County. The State Strategy will reduce ozone and PM2.5 levels statewide, thereby 

ensuring progress towards both the state ozone and PM2.5 standards throughout California. The 

State Strategy, including the proposed statewide emission control measures, revisions, and 

appendices, is available on ARB’s State Implementation Plan website. 
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Table 3-7 

Expected 2012 Emission Reductions from Proposed New SIP Measures 

Proposed New California SIP Measures Reductions (tpd) 

Ventura County Specific ROG NOx 

Passenger Vehicles 

 Smog Check Improvements (BAR) 0.7 0.8 

 Expanded Vehicle Retirement --- --- 

 Modified Reformulated Gasoline Program 0.3 --- 

 Total Reductions 1.0 0.8 

Heavy-Duty Trucks 

 Cleaner In-Use Heavy-Duty Trucks 0.2 1.7 

 Total Reductions 0.2 1.7 

Goods Movement Sources 

 Auxiliary Ship Engine Cold Ironing & Clean Technology --- 0.3 

 Cleaner Main Ship Engines and Fuel --- 3.1 

 Port Truck Modernization --- --- 

 Accelerated Introduction of Cleaner Line-Haul Locomotives --- --- 

 Clean Up Existing Harbor Craft --- 0.5 

 Total Reductions --- 3.9 

Off-Road Equipment 

 Cleaner In-use Off-Road Equipment (over 25hp) 0.0 0.0 

 Cleaner In-use Agricultural Equipment NYQ NYQ 

 Total Reductions 0.0 0.0 

Other Off-Road Sources 

 New Emission Standards for Recreational Boats 0.0 0.0 

 Expanded Off-Road Recreational Vehicle Emission Standards 0.3 --- 

 Additional Evaporative Emission Standards NYQ --- 

 Vapor Recovery for Above Ground Storage Tanks NYQ --- 

 Total Reductions 0.3 0 

Areawide Sources

 Consumer Products Program 0.4 --- 

 Total Reductions 0.4 --- 

Total Control Measure Reductions 1.9 6.4 

NOTES: 

NYQ = Not Yet Quantified. 

BAR = Bureau of Automotive Repair. 

Emission reductions reflect the combination impact of regulations and supportive incentive programs. 

Data rounding may affect displayed values and totals. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 51 

4. EMISSIONS INVENTORY FORECAST 

This chapter summarizes the ROG and NOx emissions inventory for future years. The forecast 

contains other air pollutants, however only ROG and NOx are pertinent to ozone formation and 

emission forecast reporting requirements. The 2007 AQMP incorporates all anthropogenic 

emission categories using the latest emission estimates and control implementation schedule. 

Revised emission forecasts are calculated using the actual 2002 base year emission inventory 

presented in Chapter 2, 2002 Baseline Emissions Inventory, and revised control measure data in 

Chapter 3, Control Strategy. 

4.1. Forecast Methodology 

The 8-hour Ozone SIP base year emissions inventory and future year emissions forecast is a joint 

effort by the District and the ARB. The ARB California Emission Forecasting System (CEFS) is 

a computer model that uses pollutant-specific algorithms to calculate future year emissions for all 

areas throughout the state. The District relies on this model to produce future-year and historicalyear emissions in accordance with EPA’s 8-Hour Ozone SIP and the CCAA of 1988 emissions 

inventory reporting requirements. 

Forecasted emissions are a product of two major components: growth factors and control factors. 

The forecast methodology involves applying growth and control factors to the 2002 base year 

emissions. District staff calculates the growth and control factors by analyzing the 2002 actual 

emissions, future socioeconomic assumptions and the future impact of state and federal control 

strategies. The forecast model computes the summer day ROG and NOx emissions specific to 

Ventura County for 2008, 2011, and 2012. 

The formula used in ARB’s CEFS emission forecasting model is: 

FYt= BY*GFt*CFt

 Where: 

 FYt = controlled planning day emissions for the forecast year (t) 

 BY = base year (2002) planning day emissions per process 

 GFt = growth factor for forecast year (t) 

 CFt = control factor for forecast year (t) 

Growth factors (GF) account for changes in future year socioeconomic conditions relative to the 

2002 base year using a variety of activity indicators. Activity indicators such as population, 

housing, and employment data are collected to track the economic status or social trends of the 

surrounding area. District and ARB staff assign activity indicators to emissions categories that 

best characterize the source activity and characteristic trend. The District updates the 

socioeconomic data used in the CEFS model every SIP planning cycle and as an ongoing process 

for rule development analyses. The growth factors reflect the change in future year ROG and 

NOx emissions relative to the base year. ARB maintains the statewide CEFS model and can 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 52 MAY 2008 

calculate growth factors from the District-submitted data. The forecast indicators, growth factors, 

and data sources used primarily in the CEFS v1.06 are presented in Table 4-1. 

Control factors (CF) represent the overall expected effectiveness of each control measure to 

reduce emissions. All emission categories in a base year are reviewed for potential assignment to 

control measures and updated for the required reporting years. District staff calculates control 

measure effectiveness estimates based on the best data available, knowledge of local sources 

already under control, and future control technologies. Control factors may change in the future 

as better information becomes available during the rule development process. 

A control factor is a composite of the following four multipliers: 

(1) technological control efficiency (CE) of the control technology, equipment or strategy 

requirements of the control measure; 

(2) compliance efficiency, or rule effectiveness (RE) of the control measure, reflecting the 

actual “real world” ability of a control measure to achieve expected emission reductions; 

(3) rule penetration (RP), or impact factor, representing the relative amount of emissions in a 

source category subject to a control measure, accounting for exemptions and other control 

measures; and, 

(4) implementation factor (IP), or relative amount of total control occurring in a given year, 

for control measures having phased implementation or control requirements occurring in 

tiers. 

Control factors are used to generate the remaining uncontrolled emissions in a source category 

after control is applied, represented by the following equation: 

CF = 1-(CE*RE*RP*IP) 

Each customized control factor is specific to an emission source and reflects a future year’s 

anticipated emission control, and is relative to the level of control in the 2002 base year. 

Chapter 3, Control Strategy includes a summary table showing the overall control measure 

emission reductions and control measure descriptions. 

For mobile sources, CEFS integrates the emission estimates from the EMFAC model for on-road 

vehicles and the OFFROAD model for other mobile sources. Growth assumptions for these 

mobile source categories are a product of collaboration among transportation agencies, local 

planning agencies, ARB, and SCAG. This plan uses the most current version of those emission 

estimates modeled by the SCAG regional transportation model and the ARB EMFAC and 

OFFROAD mobile source models. Table 4-2 shows important motor vehicle growth indicators 

from the ARB EMFACv2.3 on-road mobile model and the SCAG 2008 RTP as of March 12, 

2008. 
Table 4-1 

Future Year Growth Factor Summary 

Ventura County 2008 2011 2012 2002 Base Year Forecast Indicator GF GF GF Data Source No Growth (Unity) 1.00 1.00 1.00 District Population 1.08 1.12 1.13 SCAG/SCAQMD Regional Transportation Plan Dwelling Units 1.08 1.12 1.13 SCAG/SCAQMD Regional Transportation Plan Total Employment 1.05 1.10 1.11 SCAG/SCAQMD Regional Transportation Plan Oil Production 0.98 0.95 0.94 CA Dept of Conservation Division of Oil, Gas & GeotheNatural Gas Production 0.97 0.94 0.93 CA Dept of Conservation Division of Oil, Gas & GeothePetroleum Wells 0.97 0.95 0.95 CA Dept of Conservation Division of Oil, Gas & GeotheMotor Vehicle Fuel Use 1.06 1.10 1.11 ARB - EMFAC2005 Refinery Throughput 0.88 0.82 0.81 CA Dept of Conservation Division of Oil, Gas & GeotheLandfill Waste in Place 1.24 1.38 1.42 CA Integrated Waste Mgmt Board & Ventura Co. Solid Thermal Enhanced Oil Recovery 1.20 1.14 1.12 CA Dept of Conservation Division of Oil, Gas & GeotheCivilian Aircraft Operations 0.92 0.93 0.93 Ventura County Department of Airports Electric Generating-Natural Gas Usage 1.31 1.36 1.36 Ventura County Power Plants Military Aircraft 1.40 1.49 1.50 US Navy/CBC/Contractor Military Vessels 1.81 1.84 1.85 US Navy/CBC/Contractor Residential Wood Fireplaces 1.07 1.10 1.11 ARB/Pechan and Associates Consumer Product Use 1.00 1.00 1.00 California Department of Finance Population Non-Methyl Bromide Structural Pesticide 1.08 1.12 1.13 ARB/Department of Pesticide Regulation Train Locomotives - Road Hauling 1.10 1.15 1.17 ARB Livestock Waste 1.00 1.00 1.00 Statewide Ag Census/Ventura County Ag Commissioner Irrigated/Non-irrigated Grazing Acres 1.06 1.10 1.11 CA Dept of Conversation Farmland Mapping & MonitorIrrigated Acres 0.99 0.99 0.99 CA Dept of Conversation Farmland Mapping & MonitorAgricultural Aircraft 0.85 0.77 0.75 ARB/California Ag Aircraft Association Livestock Waste - Range Cattle 1.00 1.00 1.00 USDA Ag Census/Ventura County Ag Commissioner Wine Grape Acreage 1.00 1.00 1.00 USDA Wine Grape Acreage Report 

MAY 2008 

PAGE 53 
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PAGE 54 MAY 2008 

Table 4-2 

Motor Vehicle Growth Trends 

Ventura County 

Totals Indicator 2002 2008 2011 2012 

Population Residents 787,416 841,991 868,554 876,505 

All vehicle categories Vehicles 615,632 659,789 694,105 703,207 

Vehicle miles traveled 

 (x 1000) 

VMT/ 

1000 18,767 19,323 20,001 20,180 

All vehicle trips Trips 4,298,330 4,446,720 4,669,700 4,730,400 

Gasoline 956.4 967.0 999.3 1001.5 Fuel Consumption 

 (1000 gallons) Diesel 85.1 93.8 100.7 103.0 

NOTES: 

EMFAC2007v2.3; Nov 1, 2006 **WIS Enabled**. 

Run Date: 03/12/2008 10:47:42, Enhanced Interim I/M (2001). 

Season: Summer. 

The ARB Planning and Technical Support Division has the primary responsibility for developing 

on-road and off-road mobile source emissions in California. The ARB mobile source 

mathematical models, EMFAC and OFFROAD, produce future year inventories by geographic 

area for all pollutants. Appendix C includes a summary of the EMFAC2007v2.3, (Run date: 

March 12, 2008) on-road motor vehicle summer day emissions inventory for the base year and 

forecast years specific to Ventura County. 

4.1.1. External Adjustments to CEFS v1.06

The external adjustments listed below describe the recent ARB emissions inventory adjustments 

accounted for external to the ARB CEFS v1.06. The adjustments incorporate the most recent data 

changes to the emissions inventory identified by ARB specific to Ventura County and 

documented on ARB’s State Implementation Plan website in Appendix A. The external 

adjustments are included in the RFP calculations in Chapter 5 and detailed in Table 4-3. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 55 

Table 4-3 

ARB Adjustments to Emissions Inventory Baseline 

(tons per day) 

Ventura County 2002 2008 2011 2012 

ROG 

HHDD Trucks 0.00 0.00 0.00 0.00 

Pesticides/Fertilizers Adj. -3.02 -0.14 0.53 0.54 

HDD Reflash 0.00 0.00 0.00 0.00 

Public/Utility Fleet 0.00 0.00 0.00 0.00 

Truck Idling 0.00 0.00 0.00 0.00 

Assembly Bill (AB) 1493 0.00 0.00 -0.01 -0.03 

Carl Moyer Program 0.00 -0.01 -0.01 -0.01 

Consumer Products 0.00 -0.22 -0.23 -0.23 

Ship Auxiliary Engine 0.00 0.00 0.00 0.00 

Off-road Engines 0.00 0.00 -0.02 -0.03 

Total -3.02 -0.36 0.26 0.24 

 

NOx 

HHDD Trucks 0.00 0.00 0.00 0.00 

HDD Reflash -0.02 -0.25 -0.18 -0.16 

Public/Utility Fleet 0.00 0.00 0.00 0.00 

Truck Idling 0.00 -0.21 -0.23 -0.24 

AB 1493 0.00 0.00 0.00 0.00 

Carl Moyer Program -0.15 -0.11 -0.19 -0.19 

Ship Auxiliary Engines 0.00 -0.08 -0.10 -0.10 

Off-road Engines 0.00 -0.12 -0.38 -0.39 

Total -0.17 -0.78 -1.08 -1.09 

NOTES: 

ROG and NOx adjustments as of 03/06/2008. 

These adjustments include rules adopted through Dec. 31, 2006 and recently identified 

uninventoried emission categories. These adjustments are not included in CEFS v1.06. 

Data rounding may affect displayed values and totals. 

• HHDD Trucks: ARB’s on-road motor vehicle emissions model (EMFAC2007) estimate 

for 2005 for this category was adjusted to match transportation agency VMT estimates. 

• Pesticide/Fertilizer Adjustment: Update of the historical pesticide usage report (PUR) 

data 1990 - 2004 from the Department of Pesticide Regulation (DPR) and the 

corresponding adjustment for the 5-year average base year inventory. 

• HDD Reflash: Diesel engine software upgrade rule to reduce heavy-duty truck NOx 

emissions (adopted March 2004). 

• Public/Utility Fleet Rule: Rule to reduce diesel truck emissions in government and private 

utility fleets (adopted December 2005). 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 56 MAY 2008 

• Truck Idling: Rule to limit general truck idling to 5 minutes (adopted July 2004) and rule 

to limit sleeper cab truck to 5 minutes idling or use of an auxiliary power unit (adopted 

October 2005). 

• AB 1493: Criteria air pollutant benefits from the greenhouse gas (GHG) limits for motor 

vehicles adopted in September 2004. 

• Carl Moyer Program: Emission reductions from the Carl Moyer Program from 2007 

through 2015 ($81 million in funding statewide). 

• Consumer Products: Lower consumer product emission limits (adopted November 2006). 

• Ship Auxiliary Engines: Rule to require ships to use cleaner marine gas oil or diesel to 

power auxiliary engines within 24 nautical miles of the California coast (adopted 

December 2005). 

• Off-Road Engines: 

1) Rule to reduce emissions from new truck refrigeration trailers (adopted February 

2004). 

2) Rule to reduce emissions from new portable construction, mining, and industrial 

equipment (adopted February 2004). 

3) Rule to reduce emissions from forklifts, generators, and pumps (adopted May 2006). 

4.1.2. Emission Reduction Credits

EPA policy and the federal CAAA mandate pre-baseline ERCs be treated as potential growth in 

forecast years. ERCs are previous emission reductions that offset emissions growth from a new 

or modified permitted facility. Unless pre-baseline ERCs are included in future year growth 

factors, future year forecasted inventories must be adjusted to account for pre-baseline inventory 

ERCs. 

Total available ERCs balances as of January 2002 were 1.67 tons/day ROG and 0.51 tons/day 

NOx. These total ERC values are included as a separate line item adjustment to the forecasted 

emission inventory to ensure credited emission reductions are accounted for as potential future 

growth and not as permanent emission reductions. This is based on the conservative assumption 

that all pre-baseline ERCs will be used to offset emission increases from permitted facilities, 

therefore the entire balance is included in forecast inventories as potential growth. 

4.2. Emissions Forecast Summary 

ROG and NOx summer planning emissions in the SCC Air Basin (onshore Ventura County and 

within three miles of the coastline) for the 2002 base year and forecast years 2008, 2011, and 

2012 are presented in the figures and tables below. Forecast emissions represent the effects of 

future socioeconomic changes and implementation of local, state, and federal control measures. 

Figure 4-1 and Figure 4-2 present emission trends from the base year through the interval of 

forecast years by major emission category. Table 4-4 and Table 4-5 summarize base year 

emissions by major source category in descending order. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 57 

Significant reductions in ROG summer planning emissions are shown in Figure 4-1 and Table 

4-4. ROG summer planning emissions should decrease by 11 tons/day, 18% by 2012. Quantities 

and percentages of ROG emission reductions are described below. 

• Mobile Sources: 12.4 tons/day (36%). 

• On-Road Vehicles: 10.3 tons/day (51%). 

Although On-Road Vehicles represent the largest emission category in the base year, 

responsible for 34% of ROG emissions in 2002, by 2012 this category comprises 21% 

of the total. Nearly three quarters of the emission reductions are in place by 2008. 

• Other Mobile Sources: 2.1 tons/day (14%). 

This category contributes about 24% of ROG in 2002, the third leading emission 

category in the base year. By 2012, approximately 27% of total ROG emissions are 

from Other Mobile Sources, becoming the second largest emission source category. 

• Stationary Sources: 0.3 tons/day (1%). 

• Solvent Use: 1.1 tons/day (7%). 

Solvent Use includes evaporative emissions from consumer products, architectural 

coatings, surface coatings, and cleaning solvent use. Solvent use accounts for almost 

27% of ROG emissions in 2002, but is 31% of 2012 emissions, becoming the largest 

ROG emission category. 

• Pesticide Application: increases 0.8 tons/day (+21%). 

Pesticide Application is almost entirely attributable to agricultural pesticides (methyl 

bromide use), and contributes nearly 7% of total ROG in 2002. By 2012, ROG 

emissions from Pesticide Application becomes 10% of the total ROG emissions. 

• Petroleum Industry and Other Sources. 

Stationary and residential fuel combustion, agricultural burning, industrial processes 

related to manufacturing, and waste disposal are relatively small emission categories, 

and are not expected to change significantly from the base year. 

As shown in Figure 4-2 and Table 4-5, total NOx summer emissions decrease substantially by 

2012, declining nearly 22 tons/day or nearly 36%. The vast majority of emission reductions 

are attributable to Mobile Sources. Amounts and percentages of emission reductions are 

shown below. 

• Mobile Sources: 22.4 tons/day (41%). 

• On-Road Vehicles: 15.3 tons/day (51%). 

On-Road Vehicles are responsible for over 48% of NOx emissions in 2002, and 37% 

by 2012. Over two thirds of the total NOx emission reductions occur by 2008. 

• Mobile Equipment: 5.3 tons/day (34%). 

Mobile Equipment categories represent 25% of NOx emissions in 2002 and 26% by 

2012. 
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PAGE 58 MAY 2008 

• Other Mobile Sources: 1.8 tons/day (20%). 

Other Mobile Sources include aircraft, train locomotives, ships and commercial boats, 

recreational boats, off-road recreational vehicles and farm equipment. Other Mobile 

Sources account for approximately 14% of NOx in 2002, but by 2012, represent 18% 

of total NOx emissions. 

• Stationary Sources: 0.2 tons/day (2%). 

• Other Fuel Combustion: 0.5 tons/day (8%). 

Other Fuel Combustion includes stationary industrial and commercial sources, 

agricultural irrigation engines, residential uses, and agricultural burning, with the 

exception of electric utilities and oil and gas production. Other Fuel Combustion 

sources contribute approximately 9% of NOx in 2002 and 13% in 2012. 

• Electric Utilities and the Petroleum Industry. 

These sources contribute less than 3% of NOx emissions and about 5% by 2012. 

The summary ROG and NOx emissions forecast by Major Source Category by air basin follow in 

Table 4-6 and Table 4-7 for 2002, 2008, 2011 and 2012. In addition, the relative contributions by 

major emission category appear in Figure 4-3 and Figure 4-4 for ROG and NOx planning 

emissions for 2012. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 59 

Figure 4-1 

ROG Major Source Category Trends 

0

5

10

15

20

25

2002 2008 2011 2012

Years

tons/summer day

On-Road Vehicles

Solvent Use

Other M obile Sources

Pesticide Application

Petroleum Industry

Other

Table 4-4 

Summer Planning Day ROG Emissions 

Major Emission ROG (tons/summer day) 

Category 2002 2008 2011 2012

On-Road Vehicles 20.31 12.64 10.54 9.98 

Solvent Use 15.84 14.08 14.58 14.75 

Other Mobile Sources 14.59 13.61 12.74 12.52 

Pesticide Application 3.99 4.82 4.82 4.82 

Petroleum Industry 3.23 3.13 3.10 3.10 

Other 1.67 1.76 1.81 1.82 

ERC Balance 0.00 1.67 1.67 1.67 

ROG Total Emissions 59.64 51.69 49.26 48.65 

NOTES: 

Based on ARB CEFS v1.06 and ARB Adjustments 03/06/2008. 

Data rounding may affect displayed values and totals. 

Includes revised On-road Vehicle Emissions 03/12/2008. 

OCS not included. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 60 MAY 2008 

Figure 4-2 

NOx Major Source Category Trends 

0

5

10

15

20

25

30

35

2002 2008 2011 2012

Years

tons/summer day

On-Road Vehicles

M obile Equipment

Other M obile Sources

Other Fuel Combustion

Electric Utilities

Petroleum Industry

Table 4-5 

Summer Planning Day NOx Emissions 

Major Emission NOx (tons/summer day) 

Category 2002 2008 2011 2012

On-Road Vehicles 30.00 19.52 15.80 14.67 

Mobile Equipment 15.61 12.73 10.88 10.30 

Other Mobile Sources 8.88 8.00 7.24 7.11 

Other Fuel Combustion 5.71 5.41 5.28 5.23 

Electric Utilities 1.36 1.62 1.68 1.69 

Petroleum Industry r 0.27 0.25 0.24 0.24 

ERC Balance 0.00 0.51 0.51 0.51 

NOx Total Emissions 61.83 48.05 41.65 39.75 

NOTES: 

Based on ARB CEFS v1.06 and ARB Adjustments 03/06/2008. 

Includes revised On-road Vehicle Emissions 03/12/2008. 

Data rounding may affect displayed values and totals. 

OCS not included. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 61 

Table 4-6 

Adjusted ROG Planning Emission Forecast by Major Source Category 

Ventura County ROG (tons/summer day) 

Major Source Category Name 2002 2008 2011 2012 

SCC AIR BASIN 

Stationary Sources 

Fuel Combustion 0.76 0.78 0.78 0.78 

Waste Disposal 0.09 0.12 0.13 0.13 

Cleaning and Surface Coatings 6.30 5.53 5.78 5.85 

Petroleum Production and Marketing 3.10 3.00 2.97 2.97 

Industrial Processes 0.37 0.38 0.40 0.40 

Total Stationary Sources 10.62 9.81 10.06 10.14 

Area-wide Sources 

Solvent Evaporation 13.53 13.36 13.62 13.71 

Miscellaneous Processes 0.59 0.61 0.63 0.63 

Total Area-wide Sources 14.12 13.97 14.25 14.34 

Mobile Sources 

On-road Motor Vehicles 20.31 12.64 10.54 9.98 

Other Mobile Sources 14.59 13.61 12.74 12.52 

Total Mobile Sources 34.90 26.24 23.29 22.50 

 

TOTAL SCC AIR BASIN 59.64 50.02 47.59 46.98 

ERC Balance ---- 1.67 1.67 1.67 

TOTAL SCC AIR BASIN (ADJUSTED) 59.64 51.69 49.26 48.65 

 

OCS AIR BASIN 

Stationary Sources 

Fuel Combustion 0.03 0.04 0.04 0.04 

Cleaning and Surface Coatings 0.01 0.00 0.00 0.00 

Petroleum Production and Marketing 0.04 0.04 0.04 0.04 

Total Stationary Sources 0.09 0.08 0.08 0.08 

Mobile Sources 

Other Mobile Sources 0.63 0.74 0.78 0.79 

Total Mobile Sources 0.63 0.74 0.78 0.79 

 

TOTAL OCS AIR BASIN 0.72 0.82 0.86 0.87 

 

TOTAL VENTURA COUNTY(ADJUSTED) 60.36 52.51 50.12 49.52 

NOTES: 

Source: ARB CEFS v1.06 (November 2006). 

Revised On-Road Vehicle emissions (03/12/2008) and ARB Adjustments (03/06/2008). 

Data rounding may affect totals. 
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Table 4-7 

Adjusted NOx Planning Emission Forecast by Major Source Category 

Ventura County NOx (tons/summer day) 

Major Source Category Name 2002 2008 2011 2012 

SCC AIR BASIN 

Stationary Sources 

Fuel Combustion 5.88 5.75 5.64 5.59 

Waste Disposal 0.09 0.11 0.12 0.12 

Cleaning and Surface Coatings 0.00 0.00 0.00 0.00 

Petroleum Production and Marketing 0.04 0.03 0.03 0.03 

Industrial Processes 0.08 0.08 0.08 0.08 

Total Stationary Sources 6.08 5.97 5.87 5.82 

Area-Wide Sources 

Solvent Evaporation 0.00 0.00 0.00 0.00 

Miscellaneous Processes 1.27 1.32 1.34 1.35 

Total Area-Wide Sources 1.27 1.32 1.34 1.35 

Mobile Sources 

On-Road Motor Vehicles 30.00 19.52 15.80 14.67 

Other Mobile Sources 24.49 20.73 18.13 17.41 

Total Mobile Sources 54.49 40.25 33.93 32.08 

 

TOTAL SCC AIR BASIN 61.83 47.54 41.13 39.24 

ERC Balance ---- 0.51 0.51 0.51 

TOTAL SCC AIR BASIN (ADJUSTED) 61.83 48.05 41.64 39.75 

 

OCS AIR BASIN 

Stationary Sources 

Fuel Combustion 0.39 0.40 0.41 0.41 

Cleaning and Surface Coatings 0.00 0.00 0.00 0.00 

Petroleum Production and Marketing 0.01 0.01 0.01 0.01 

Total Stationary Sources 0.40 0.41 0.41 0.42 

Mobile Sources 

Other Mobile Sources 12.96 15.80 17.43 18.04 

Total Mobile Sources 12.96 15.80 17.43 18.04 

 

TOTAL OCS AIR BASIN 13.36 16.20 17.84 18.45 

 

TOTAL VENTURA COUNTY (ADJUSTED) 75.19 64.25 59.48 58.20 

NOTES: 

Source: ARB CEFS v1.06 (November 2006). 

Revised On-Road Vehicle emissions (03/12/2008) and ARB Adjustments (03/06/2008). 

Data rounding may affect totals. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 63 

Figure 4-3 

Ventura County 2012 Planning Day 

ROG Emissions Inventory 

Other

4% On-Road Vehicles

21%

Solvent Use

31%

Other Mobile 

Sources

27% Petroleum Industry

7%

Pesticide Application

10%

48.65 tons/summer day

Reference: 

ARB CEFS v1.06 (Nov. 2006). 

Total emissions include ERCs. 

Excludes OCS and Natural Sources. 

Figure 4-4 

Ventura County 2012 Planning Day 

NOx Emissions Inventory 

On-Road Vehicles

37% Petroleum Industry

0.6%

Mobile Equipment

26%

Other Mobile 

Sources

18%

Other Fuel 

Combustion

13% Electric Utilities

4%

39.75 tons/summer day

Reference: 

ARB CEFS v1.06 (Nov. 2006). 

Total emissions include ERCs. 

Excludes OCS and Natural Sources. 
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4.3. Ventura County Marine-Related Emissions Forecast 

As discussed in Section 2.3, coastal and offshore marine emission sources are important segments 

of Ventura County’s overall emission inventory. A substantial effort has been made to improve 

and refine emission estimates for these emission sources, described in detail in Section 2.3. 

4.3.1. SCC Air Basin Marine-Related Emissions

Coastal marine emission sources are located in the State Tidelands within three miles of the 

Ventura County coastline in the SCC Air Basin, which also incorporates the onshore portion of 

Ventura County, including the Port of Hueneme and its approach corridors. 

As shown in Table 4-8, coastal marine emission sources include Ships and Commercial Boats, 

Recreational Boats, and Cargo Handling Equipment. Cumulatively these categories account for 

over 4 tons/day ROG and nearly 3 tons/day NOx in 2002 and well over 3 tons/day of both ROG 

and NOx in 2012. The most important ROG and NOx emission sources and their relative 

contributions to total coastal emissions in 2012 are described below. 

• Ships and Commercial Boats: 1.6 tons/day NOx (50%). 

Ships and Commercial Boats are responsible for over 45% of coastal water NOx 

emissions in 2002, increasing by 18% to account for over half by 2012. 

• Ocean-going Vessels: 0.8 tons/day NOx (24%). 

NOx emissions from Ocean-going Vessels calling on Port Hueneme (auto carriers, 

bulk cargo carriers, container vessels, passenger vessels, roll-on/roll off vehicle 

carriers, refrigerated cargo vessels and tankers) comprise 17% of the coastal total in 

2002 and are expected to increase by nearly 45% by 2012. 

• Commercial Boats and Harbor Craft: 0.5 tons/day NOx (15%). 

Commercial Boats and Harbor Craft such as commercial fishing vessels, charter 

fishing vessels, excursion boats, tug and towboats, and crew and supply boats 

associated with the four offshore oil and gas production platforms contribute over 21% 

of coastal NOx in 2002. Emissions are expected to decrease by nearly 24% by 2012. 

• Military Vessels: 0.4 tons/day NOx (11%). 

Military Vessels operations occurring at the U.S. Navy facilities at the Port of 

Hueneme include large naval ships, smaller support and operations vessels, tugboats 

and other vessels, and some non-military vessels utilizing Navy facilities. Military 

vessels account for 6% of coastal NOx emissions in 2002, and should increase by 0.2 

tons/day by 2012. 

• Recreational Boats: 3.4 tons/day ROG (92%) and 1.2 tons/day NOx (39%). 

Recreational Boats operate at the three ports, marinas and lakes in Ventura County, and 

include vessels with outboard, inboard and stern-drive engines, sailboat auxiliary engines, 

and personal watercraft. Recreational vessels account for 92% of the ROG emissions in 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 65 

2002 and 2012, despite decreasing by about 13% (0.5 tons/day) by 2012. NOx from 

recreational boats increases by nearly 39% from 30% of total 2002 emissions. 

• Cargo Handling Equipment: 0.3 tons/day NOx (11%). 

Cargo Handling Equipment includes port operations/cargo handling equipment operating 

in association with large commercial vessels calling on Port Hueneme, such as yard 

tractors, forklifts, cranes, loaders, and other material handling equipment. Cargo Handling 

Equipment generates 25% of NOx in 2002, decreasing over 53% (0.4 tons/day) by 2012. 

Table 4-8 

SCC Air Basin Marine Emission Categories 2002 – 2012 

Ventura County 

ROG Planning Day Emissions 

(tons/summer day) 

Emission Category 2002 2008 2011 2012 

Ships & Commercial Boats 0.23 0.26 0.27 0.27 

Recreational Boats 3.85 3.65 3.42 3.37 

Cargo Handling Equipment 0.09 0.04 0.03 0.03 

Total SCC Air Basin Marine ROG 4.17 3.95 3.72 3.67 

 

NOx Planning Day Emissions 

(tons/summer day) 

Emission Category 2002 2008 2011 2012 

Ships & Commercial Boats 1.35 1.54 1.57 1.59 

Recreational Boats 0.89 1.26 1.24 1.24 

Cargo Handling Equipment 0.75 0.48 0.40 0.35 

Total SCC Air Basin Marine NOx 2.99 3.28 3.21 3.18 

NOTES:

CEFS v1.06 (November 2006). 

Including ARB Adjustments (03/06/2008). 

4.3.2. OCS Air Basin Marine-Related Emissions

Offshore emission marine sources shown in Table 4-9, Figure 4-5 and Figure 4-6 occur in the 

region beyond three miles of the coastline in the OCS Air Basin and include the offshore shipping 

lanes in the Santa Barbara Channel and San Nicolas Island. The most important ROG and NOx 

emission sources and their relative contributions to total offshore emissions in 2012 are described 

below. 

• Ships & Commercial Boats: 18.0 tons/day NOx (97%) and 0.7 tons/day ROG (78%). 

This category accounts for the vast majority of emissions in the OCS Air Basin, nearly 

78% of ROG and nearly 97% of NOx in 2002. By 2012, NOx is expected to increase by 

39% (5.1 tons/day), while ROG should increase by 21%. 

• Ocean-going Vessels: 15.8 tons/day NOx (86%) and 0.5 tons/day ROG (52%) 

Ocean-going Vessels traversing the Santa Barbara Channel shipping lanes offshore of 

Ventura County include vessels calling on Port Hueneme or the ports of Los 

Angeles/Long Beach, and transiting vessels passing through southern California 
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PAGE 66 MAY 2008 

waters but without calling at either port. Commercial Ocean-going Vessels account 

for 77% of NOx and 39% of ROG in 2002. Expansion in “goods movement” activity 

by ships visiting the ports in California are expected to increase NOx and ROG 

emissions by more than 50% (5.5 tons/day NOx). 

• Commercial Boats: 1.6 tons/day NOx (8%) and 0.2 tons/day ROG (19%). 

Commercial Boats include commercial and passenger charter fishing boats, excursion 

boats, tugboats and crew & supply boats affiliated with the offshore oil and gas 

production platforms. Commercial boats contribute over a third of offshore ROG and 

about 17% of NOx in 2002. Emissions of both pollutants should decrease by about 

32% by 2012. 

• Military Vessels: 0.6 tons/day NOx (3%) and 0.1 tons/day ROG (7%). 

Military Vessels are large naval vessels, smaller support vessels, and tugboats 

operating offshore and in the approach corridors to Port Hueneme. Military vessels 

account for about 5% of 2002 offshore ROG and less than 3% of NOx emissions. By 

2012 military vessels will contribute about 7% of ROG and 3% of NOx. 

• Aircraft: 0.1 tons/day ROG (13%). 

Aircraft emissions are associated with military aircraft operations at the U.S. Naval 

facility on San Nicolas Island, including transports, jet aircraft and helicopters. Aircraft 

activities are responsible for 10% of offshore ROG emissions in 2002 and about 13% in 

2012. 

• Stationary Sources: 0.4 tons/day NOx (2%) and 0.1 tons/day ROG (9%). 

Oil & Gas Production ROG emissions include fugitive hydrocarbon losses from oil and 

gas production components and production and processing equipment on the offshore oil 

and gas production platforms; natural gas flaring is responsible for ROG and NOx 

emissions. Oil & Gas Production activities produce 6% of offshore ROG emissions in 

2002. Other offshore emission sources contributing less than 7% of total offshore ROG 

and 3% of NOx include electric generating types of equipment and routine maintenance 

operations for the offshore oil and gas production platforms and the U.S. Naval facility on 

San Nicolas Island. There should be negligible changes in emissions by 2012. 
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MAY 2008 PAGE 67 

Table 4-9 

OCS Air Basin Marine Emission Categories 2002 – 2012 

Ventura County 

ROG Planning Day Emissions 

(tons/summer day) 

Emission Category 2002 2008 2011 2012 

Ships & Commercial Boats 0.56 0.64 0.67 0.68 

Aircraft 0.07 0.10 0.11 0.11 

Oil & Gas Production 0.04 0.04 0.04 0.04 

Other 0.05 0.04 0.04 0.04 

Total OCS Air Basin ROG 0.72 0.82 0.86 0.87 

 

NOx Planning Day Emissions 

(tons/summer day) 

Emission Category 2002 2008 2011 2012 

Ships & Commercial Boats 12.92 15.74 17.36 17.97 

Aircraft 0.04 0.06 0.06 0.07 

Other 0.40 0.41 0.41 0.42 

Total OCS Air Basin NOx 13.36 16.21 17.83 18.46 

NOTES:

CEFS v1.06 (November 2006). 

Including ARB Adjustments (03/06/2008). 
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PAGE 68 MAY 2008 

Figure 4-5 

Ventura County 2012 Planning Day 

ROG Emissions Inventory (OCS Air Basin) 

Commercial

Boats

19%

Ships in Transit

52%

Fuel

Combustion

4%

Aircraft

13%

Coatings/

Solvents

0.2%

Oil and Gas 

Production

5%

Other

 Vessels

7%

0.87 tons/summer day

Reference: 

ARB CEFS v1.06 (Nov. 2006). 

OCS is 3 – 100 miles offshore. 

Figure 4-6 

Ventura County 2012 Planning Day 

NOx Emissions Inventory (OCS Air Basin) 

Commercial

 Boats

7%

Tugboats

1%

Other Vessels/

Aircraft

4%

Fuel

Combustion

2%

Ships in Transit

86%

18.45 tons/summer day

Reference: 

ARB CEFS v1.06 (Nov. 2006). 

OCS is 3 – 100 miles offshore. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 69 

4.4. Naval Base Ventura County Emission Forecasts 

The 2007 AQMP includes emissions associated with potential growth or change in activity at the 

Naval Base Ventura County (NBVC). The purpose of these projections is to include information 

in the 2007 AQMP regarding potential growth at NBVC. These emissions are included in the 

AQMP’s base year inventory and emissions forecasts. The baseline and projected emissions are 

from aircraft, missile, and ship operations. Increases in motor vehicle activity at NBVC are part 

of SCAG’s regional transportation model and are not included in these projections. These data 

represent the best available information for NBVC as of June 5, 2007. 

Table 4-10 summarizes the baseline emissions, estimated emissions from potential projects, and 

an additional 7% growth forecast for NBVC through year 2012 in the SCC Air Basin. The 7% 

growth forecast is based on an additional 1% growth factor for each year, beginning in 2006, to 

account for uncertainties in potential projects resulting from future actions. This additional 

growth would result in a base-wide emissions budget of 186.6 tons per year of ROG and 243.7 

tons per year of NOx by 2012. 

Table 4-10 

Naval Base Ventura County Emissions Budget 

(tons per year) 

2002a

 2008 2009 2010 2011 2012 

ROG 137.5 179.0 181.1 182.5 185.2 186.6 

NOx 149.6 230.7 233.8 235.3 242.2 243.7 

NOTES: a Emissions do not include emissions from missile operations. 

Source: Naval Base Ventura County Mobile Source Emissions Growth Projection 

and 8-Hour Ozone SIP Planning (6/5/2007). 
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5. FEDERAL 8-HOUR OZONE REASONABLE FURTHER PROGRESS 

5.1. Introduction 

The CAAA requires that the 2007 AQMP show steady progress towards attaining the federal 

8-hour ozone standard out to 2013, the county’s serious classification attainment date. EPA 

defines reasonable further progress (RFP) as “annual incremental reductions in air pollutant 

emissions as reflected in a State Implementation Plan that EPA deems sufficient to provide for the 

attainment of the applicable national ambient air quality standards by the statutory deadline.” A 

clean air plan must demonstrate both RFP and attainment of the applicable clean air standard to 

be approvable by EPA. It must also include contingency emission reductions if a nonattainment 

area fails to meet certain mandated milestones. 

Reasonable further progress requirements for the 8-hour ozone standard are described in EPA’s 

Final Rule to Implement the 8-Hour Ozone National Ambient Air Quality Standard, and build 

upon the requirements specified in CAAA Sections 172(c)(2), 182(b)(1)(A) and 182(c)(2)(b). 

CAAA Section 172(c)(2) is the general requirement for RFP. More specific requirements are 

given in Sections 182(b)(1)(A) and 182(c)(2)(b). Section 182(b)(1)(A) requires that moderate 

and above nonattainment areas reduce ROG at least 15 percent from baseline emissions within six 

years from the baseline year (i.e., by 2008 from 2002). Section 182(c)(2)(b) requires serious and 

above areas provide an average of three percent per year ROG and/or NOx reductions for the first 

six-year period from the baseline year, and each three-year period thereafter until their attainment 

dates. 

However, the EPA’s final RFP rule does not require serious and above 8-hour ozone 

nonattainment areas with approved 15 percent rate-of-progress ROG plans for the federal 1-hour 

ozone standard to do another 15 percent ROG-only reduction for the federal 8-hour ozone 

standard. Rather, those areas must reduce ROG and/or NOx emissions by an average of three 

percent per year for the first six-year period following the baseline year plus all remaining 

three-year periods out to their attainment dates. The federal Clean Air Act also specifies that 

areas classified moderate or higher must provide emission reductions equivalent to three percent 

of the adjusted base year inventory for contingency measures, the equivalent of one year of RFP. 

The EPA approved Ventura County’s 15 percent rate-of-progress plan on January 8, 1997. 

Therefore, the 2007 AQMP must provide an average of three percent per year of ROG and/or 

NOx reductions from 2002 through 2012, since Ventura County’s serious classification 

attainment date is June 15, 2013. It must also show attainment of the 8-hour ozone standard by 

the end of the prior ozone season (i.e., by 2012). The baseline year for this AQMP is 2002. 

Therefore, RFP milestone reporting years are 2008, 2011, and 2012. The required milestone 

ROG/NOx reductions are 18 percent for 2008, 27 percent for 2011, and 30 percent for 2012. 
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EPA guidance for calculating RFP allows for accounting for ROG emissions 100 km and NOx 

emissions 200 km from Ventura County boundaries. For Ventura County's RFP, the same 100 

km limit for both ROG and NOx was used. As such, on-shore emissions from the Los Angeles 

County portion of the South Coast Air Basin have been included in the baseline ROG and NOx 

inventories as “upwind emissions” for the RFP demonstration. 

5.2. RFP Demonstration 

Pursuant to the EPA’s Phase 2 rule for the federal 8-hour ozone standard, RFP calculations start 

with the 2002 base year emissions and reflect emission reductions from adopted state and local 

control strategies only. ARB adjusted both the base year emissions and milestone year emissions 

for measures already adopted through December 31, 2006. These adjustments are presented in 

Section 4.1.1 and detailed in Table 4-3. The adjustments are uninventoried emission categories 

and not included in CEFS v1.06. In addition, according to EPA policy, emission reduction 

benefits attributable to the federal motor vehicle control program (FMVCP) and fuel Reid Vapor 

Pressure (RVP) requirements must be discounted from the pre-1990 California motor vehicle 

program (CA MVCP). 

Table 5-1 presents the RFP demonstrations showing Ventura County meeting RFP, and the three 

percent RFP contingency requirements for the serious area milestone years, 2008, 2011, and 

2012. The adjusted baseline inventory in the table reflects the emission inventory adjustments 

presented in Table 4-3. 

For all three milestone years, 2008, 2011, and 2012, the county will achieve RFP using only ROG 

emission reductions by 6.2, 2.4, and 0.6 percent per day, respectively. Therefore, RFP for each of 

those years does not require a combination of ROG and NOx reductions (NOx substitution). 

Three percent of 2002 NOx emission reductions have been set aside for 3% contingency 

requirements in each RFP milestone year. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

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Table 5-1 

RFP Demonstration 

(tons/summer day) 

2002 2008 2011 2012 

Baseline ROG 598.8 424.9 387.6 378.4 

CA MVCP/RVP Adjustment 0.00 38.20 49.90 53.79 

RACT Corrections 0 0 0 0 

Adjusted 2002 Baseline ROG in milestone year 598.8 560.6 548.9 545.0 

RFP commitment for ROG reductions from new measures 0 0 0 

Required % change since previous milestone year (ROG or NOx) compared 

to 2002 18% 9% 3% 

Required % change since 2002 (ROG or NOx) 18% 27% 30% 

Target ROG levels 459.7 400.7 381.5 

Apparent shortfall in ROG -34.8 -13.1 -3.1 

Apparent shortfall in ROG, % -6.2% -2.4% -0.6% 

ROG shortfall previously provided by NOx substitution, % 0.0% 0.0% 0.0% 

Actual ROG shortfall, % -6.2% -2.4% -0.6% 

 

Baseline NOx 718.0 565.7 493.0 476.6 

CA MVCP Adjustment 0.00 41.85 52.15 55.58 

Adjusted Baseline NOx 718.0 676.1 665.9 662.4 

RFP commitment for NOx reductions from new measures 0 0 0 0 

Change in NOx since 2002 110.5 172.9 185.8 

Change in NOx since 2002, % 16.3% 26.0% 28.0% 

NOx reductions since 2002 already used for RFP substitution through last 

milestone year, % 0.0% 3.0% 3.0% 

NOx reductions since 2002 available for RFP substitution and contingency in this 

milestone year, % 16.3% 23.0% 25.0% 

Change in NOx since 2002 used for ROG substitution in this milestone year, % 0.0% 0.0% 0.0% 

Change in NOx since 2002 available for contingency in this milestone year, % 3.0% 3.0% 3.0% 

Change in NOx since 2002 surplus after meeting substitution and contingency 

needs in this milestone year, % 13.3% 23.0% 25.0% 

RFP shortfall, if any 0.0% 0.0% 0.0% 

RFP Met? YES YES YES 

Contingency Met? YES YES YES 

NOTES:

Includes transport contributions from the Los Angeles-South Coast Air Basin. 

From Updated Ventura RFP w-burning (3).xls, March 5, 2008, 4:57:37 PM.
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6. FEDERAL 8-HOUR OZONE MODELING AND ATTAINMENT DEMONSTRATION 

6.1. Introduction 

This chapter presents the photochemical modeling and supplemental Weight of Evidence (WOE) 

analyses conducted for the 2007 AQMP. The purpose of these analyses is to determine whether 

the proposed control strategy for the 2007 AQMP provides sufficient emission reductions to meet 

the federal 8-hour ozone standard by the attainment year. 

6.2. Photochemical Modeling and Weight of Evidence Analyses 

Section 182(c)(2)(A) of the federal CAAA requires that moderate and above ozone nonattainment 

areas attain the federal 8-hour ozone standard by specific dates based on their ozone 

nonattainment designations. Moreover, serious and above ozone nonattainment areas, including 

Ventura County, must use a photochemical grid model to show attainment. 

Photochemical grid models are computer programs that mathematically simulate each of the 

physical and chemical processes that govern air pollutant in the lower atmosphere. Such 

processes include air pollutant release into the air, air pollutant transport and diffusion by the 

wind, air pollutant creation and destruction in the air through chemical reactions, and deposition 

of pollutants onto the ground. The region analyzed by a photochemical air pollution model is 

termed the modeling region or modeling domain and is a geographical area divided into a threedimensional array of grid cells. The model calculates air pollutant concentrations in each grid 

cell for each hour of the modeling period and often displays the results graphically. 

EPA modeling guidance recommends that nonattainment areas supplement their photochemical 

modeling results with a “weight of evidence” assessment if their model predicts future-year ozone 

levels of 0.082 ppm to 0.087 ppm. The federal 8-hour ozone attainment level is 0.084 ppm. A 

WOE assessment is a set of analyses intended to verify modeled predictions of future air quality, 

especially at levels near the federal standards. These analyses can include air quality trends, 

emission trends, meteorological data, evaluation of other air quality indicators, and additional air 

quality modeling. Because all analysis methods have strengths and weaknesses, examining an air 

quality problem using various analysis methods helps offset the limitations and uncertainty 

inherent in all air quality modeling methods. The scope of the WOE analysis is different for each 

nonattainment area. The level of detail appropriate for an area depends upon the complexity of 

the air quality problem in the area, how far into the future the attainment deadline is, and the 

amount of data and modeling available. 

6.3. Attainment Demonstration 

Photochemical modeling results indicate a design value of 0.087 ppm for Ventura County by 

2013, the attainment date for serious ozone nonattainment areas. Based on photochemical 

modeling, as well as supporting analyses completed as part of the WOE evaluation, Ventura 
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PAGE 76 MAY 2008 

County can expect to reduce its design value to 0.084 ppm and attain the federal 8-hour ozone 

standard by 2013, the attainment date for serious nonattainment areas. Appendix D contains the 

photochemical modeling protocol and WOE for the 2007 AQMP. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

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7. CONTINGENCY MEASURES 

7.1. Introduction 

Clean air plans for nonattainment areas must contain contingency reductions that take effect 

without further air agency action should the areas fail to achieve RFP goals or attainment by their 

attainment deadlines. CAAA Section 172(c)(9) requires that areas implement contingency 

measures if they fail to make RFP or fail to attain the air quality standards by the required 

attainment date. Section 182(c)(9) of the CAAA requires serious and above nonattainment areas 

to implement contingency measures if they fail to meet any applicable CAAA milestone for the 

federal 8-hour ozone standard. 

Contingency measures must be specific federal, state, or local measures that will provide 

emission reductions surplus to those needed for attainment. The April 16, 1992 General Preamble 

to the CAAA of 1990 provided the following guidance regarding contingency measures: “States 

must show that their contingency measures can be implemented with minimal further action on 

their part and with no additional rulemaking actions such as public hearings or legislative review. 

In general, EPA will expect all actions needed to affect full implementation of the measures to 

occur within 60 days after EPA notifies the State of its failure (57 FR 13512). This could include 

Federal measures and local measures already scheduled for implementation.” 

The EPA has approved numerous SIPs that rely on one or more contingency measures that are in 

place and provide reductions surplus to RFP or attainment requirements. The key is that the 

statute requires extra reductions not relied on for RFP or attainment to provide a cushion while 

revising the plan to meet the missed milestone. However, nothing in the statute precludes an area 

from implementing such measures before needed by a milestone failure. 

The CAAA does not specify the number of contingency measures nor does it specify an exact 

magnitude of emission reductions that the contingency measures are to achieve. However, EPA’s 

General Preamble for Title I of the CAAA states that EPA will interpret Sections 172(c)(9) and 

182(c)(9) as requiring additional emission reductions of up to three percent of the emissions in the 

adjusted base year inventory. Moreover, the reductions must occur in the year following the year 

in which the failure occurred. 

EPA allows substitution of NOx contingency measures for ROG contingency measures if two 

conditions are met. First, the area must need NOx reductions to reduce ambient ozone 

concentrations. Second, a minimum of ten percent of the required contingency measures must be 

from ROG measures. 
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7.2. Reasonable Further Progress and Attainment Contingency Measures 

7.2.1. RFP Contingency Measures

The CAAA specifies that each ozone non-attainment area must demonstrate ongoing emission 

reductions relative to the emission inventory base year (2002). Federal law requires a three 

percent per year reduction in VOC emissions and does not allow credit to be taken for pre-1990 

federal motor vehicle control programs. Where both VOC and NOx emissions have been shown 

to contribute to high ozone levels, the Clean Air Act allows NOx emission reductions to be used 

to augment VOC emission reductions in order to demonstrate reasonable further progress. In 

nonattainment areas that are impacted by transport from other regions, emissions and emission 

reductions from those regions are taken into account when assessing reasonable further progress. 

Air quality modeling, described in Section 5, demonstrates that emissions from the South Coast 

Air Basin contribute to violations of the federal ozone standard in Ventura County. 

Table 5.1 demonstrates that the RFP projected for Ventura County meets CAA requirements and 

is met using ROG emissions only. The RFP assessment takes into account projected emissions 

for upwind areas within 100 kilometers (the Los Angeles County portion of the South Coast Air 

Basin) as allowed by EPA guidance. 

The emissions inventory indicates that the adopted measures from ARB’s mobile source program 

will provide emissions reductions beyond those needed for Ventura County’s RFP demonstration. 

As part of the RFP demonstration, Ventura County will rely on a portion of surplus NOx 

reductions to provide for 3% contingency reductions in the 2008 and 2011 RFP milestone years. 

7.2.2. Attainment Contingency Measures

ARB, in its 2007 SIP, has committed to include the emissions benefits of one additional year of 

its motor vehicle program, including vehicle fleet turnover, and light-duty vehicle inspection and 

maintenance programs, in the year following each area’s attainment year for attainment 

contingency measures. This commitment will meet Ventura County’s attainment contingency 

obligation. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 79 

8. CALIFORNIA OZONE TRIENNIAL ASSESSMENT AND PLAN UPDATE 

The CCAA requires that the District assess the progress the county has made towards meeting the 

state ambient 1-hour ozone standard during the previous three years (2003 through 2005). The 

CCAA also requires periodic plan updates for attaining the state 1-hour ozone standard. The 

2007 AQMP satisfies both of these CCAA requirements. 

The 2007 AQMP reports on the progress the county has made over the reporting period for the 

state 1-hour ozone standard. The state and local control programs presented in the 2007 AQMP 

for the federal 8-hour ozone standard will ensure that Ventura County continues to make progress 

towards the more stringent state 1-hour ozone standard. The deadline for the triennial 

assessments was December 31, 2006. However, ARB revised the deadline to correspond with 

federal SIP submittals. 

By being a comprehensive clean air plan for the federal 8-hour ozone standard, the 2007 AQMP 

incorporates considerable new data and projections. In addition, most of the federal planning 

mandates for the 8-hour ozone standard addressed by the 2007 AQMP also address most of the 

planning requirements for the 1-hour state ozone standard. District staff has not identified any 

deficiencies with respect to meeting progress goals towards the state 1-hour ozone standard. 

8.1. Triennial Assessment and Plan Update Requirements 

California Health and Safety Code Sections 40924 and 40925 require that the Triennial 

Assessment Plan Update include the following: 

• Improvement in air quality based upon air quality indicators identified by the ARB 

(Section 40924); 

• Population-related, industry-related, and vehicle-related emissions growth (Section 

40925); 

• Control measures adopted by the District (Sections 40924 and 40925); and, 

• Review of “every feasible measure” (Section 40925). 

Table 8-1 provides a more complete list of triennial plan requirements and where those 

requirements are met in the 2007 AQMP. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 80 MAY 2008 

Table 8-1 

CCAA Triennial Assessment Requirements 

Requirement Submittal 

Air Quality Analysis Chapters 1 (Section 1.5.) & Chapter 8 (Section 8.2.) 

Contingency Measures Chapter 7 

Control Measures Chapter 3 & Chapter 8 (Section 8.5.) 

Control Strategy Cost-Effectiveness Chapter 8 (Section 8.5.1.) 

Emission Inventory Chapter 2 & Chapter 4 

Every Feasible Measure Chapter 8 (Section 8.6.) 

Expeditious Adoption Chapter 8 (Section 8.6.) 

Population Exposure Chapter 8 (Section 8.2.) 

Public Information Chapter 8 (Section 8.9.) 

Ozone Transport Chapter 8 (Section 8.7.) 

Population Trends Chapter 4 (Section 4.1.) 

Transportation Control Measures Chapter 3 (Section 3.2.) 

Vehicle Trips & VMT Trends Chapter 4 (Sections 4.1. & 4.1.2.) 

8.2. Air Quality Indicators 

The ARB recommends local districts use three air quality indicators to assess progress in meeting 

the state ambient 1-hour ozone standard: population-weighted exposure, area-weighted exposure, 

and expected peak day concentration. As discussed below, these indicators show that Ventura 

County has made excellent progress towards meeting the state 1-hour ozone standard. Further 

information regarding current and historical air quality data for Ventura County is available on 

the District’s Air Quality Monitoring Division website. 

8.2.1. Population-Weighted Exposure & Area-Weighted Exposure

Population-weighted Exposure: This indicator characterizes the potential average outdoor 

exposure per person to concentrations above the state ozone standard. It represents a composite 

of exposure around each air quality monitoring site weighted to emphasize equally the exposure 

for each person in Ventura County. The exposure value hence represents the number of hours 

multiplied by the ozone concentration over the California standard that the average person 

experiences, expressed in parts per hundred million (pphm) per person. However, 

population-weighted exposure represents the average potential exposure in the District, and not 

health impacts on individuals. The term “potential” denotes a person’s possible daily exposure 

and not actual daily exposure. For example, being indoors during peak ozone concentrations will 

decrease a person’s actual exposure to outdoor ozone concentrations. 

Health and Safety Code Section 40920 requires the District to reduce exposure to ozone levels in 

excess of the state standard from average 1986 - 1988 levels by at least 25 percent in 1994, by 40 

percent in 1997, and 50 percent in 2000. Figure 8-1 presents the trend in three-year average 

population-weighted exposure to levels above the state ozone standard, as recommended by the 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 81 

ARB. It shows population-weighted exposure in Ventura County has been reduced significantly 

since 1986 - 1988, and at a faster rate than required by Section 40920. By 2000, populationweighted exposure declined by 93 percent, compared to the 2000 target of 50 percent. By 2002, 

population-weighted exposure declined by 96 percent and nearly 99 percent by 2005. 

Area-weighted Exposure: This indicator characterizes the potential average annual outdoor 

exposure per unit area. It represents a composite of exposure around each air quality monitoring 

site weighted to equalize the exposure throughout Ventura County. Area-weighted exposure is 

calculated similarly to population-weighted exposure, except the census tract ozone 

concentrations are multiplied by the square kilometers in the census tract. Exposure values are 

then summed and divided by the total square kilometers in the county. 

As indicated, the District is required to reduce exposure to ozone levels in excess of the state 

standard from average 1986 - 1988 levels by 25 percent in 1994, by 40 percent in 1997, and by 50 

percent in 2000. Figure 8-1 presents the county’s downward trend in three-year average areaweighted exposures to ozone levels above the state ozone standard. As can be seen, areaweighted exposure has declined significantly since 1986 - 1988. By 2000, area-weighted 

exposure in Ventura County declined by 94 percent, compared to the 2000 target of 50 percent. 

By 2002, area-weighted exposure declined by 95 percent, and 98 percent by 2005. 

Figure 8-1 

Population & Area-Weighted Exposure 

0

50

100

150

200

250

300

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

Exposure

(pphm-hrs/person & pphm-hrs/sq. km)

Population-Weighted Exposure

Area-Weighted Exposure

0

10

20

30

40

50

60

1998

1999

2000

2001

2002

2003

20042005

0

50

100

150

200

250

300

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

Exposure

(pphm-hrs/person & pphm-hrs/sq. km)

Population-Weighted Exposure

Area-Weighted Exposure

0

10

20

30

40

50

60

1998

1999

2000

2001

2002

2003

20042005
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 82 MAY 2008 

8.2.2. Expected Peak Day Concentration

Expected peak day concentration (EPDC) represents the maximum ozone concentration 

anticipated to occur once per year, on average. It is based on a statistical calculation of daily 

maximum 1-hour ozone data collected at each air quality monitoring site in the county over a 

three-year period. The EPDC is useful for tracking air quality progress at individual air quality 

monitoring locations. Because it uses a robust statistical calculation, it is relatively stable, 

thereby providing a trend indicator that is not highly influenced by year-to-year variations in 

meteorology. 

Table 8-2 presents a summary of the EDPC values calculated by ARB for the Ventura County air 

quality monitoring sites for 1986 and 2005. Figure 8-2 graphically presents the corresponding 

percent reduction in expected peak day concentration values for each of the air quality monitoring 

stations. Peak day ozone concentrations have significantly declined over the period. The percent 

reductions range from 21.1 percent in Ojai to 42.6 percent in El Rio. The average reduction was 

over 30.1 percent. 

Table 8-2 

Expected Peak Day Ozone Concentrations 

Monitoring Site

1986-

1988 

1989-

1991 

1992-

1994 

1995-

1997 

1998-

2000 

2000-

2002 

2003-

2005 

Total Percent 

Reduction 

from 1986-1988 

Simi Valley 17.6 16.4 14.7 15.3 13.2 12.5 11.6 34.1 

Ojai 14.2 14.1 13.0 12.2 11.3 12.1 11.2 21.1 

El Rio 14.1 12.6 12.0 10.9 9.1 8.3 8.1 42.6 

Piru 14.2 13.4 11.8 11.7 10.3 11.7 11.1 21.8 

Thousand Oaks 15.2 14.0 13.2 13.1 11.2 10.2 10.7 29.6 

Ventura 12.9 12.5 10.6 11.0 8.5 8.3 8.8 31.8 

NOTES: 

Expected peak day concentration for ozone, in parts per hundred million (pphm). 

Source: Air Resources Board (September 2006). 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 83 

Figure 8-2 

Percent Reduction in Expected Peak Day Ozone Concentrations: 1986 – 2005 

Simi Valley

Ojai

El Rio

Piru

Thousand Oaks

Ventura

0

3

6

9

12

15

18

21

24

27

30

33

36

39

42

45

48

Percent Reduction

8.3. Emissions Trends 

Chapter 4, Emissions Inventory Forecast, presents updated emission control and forecast 

information, including population and motor vehicle growth trends, for 2002 through 2012 for 

stationary, area, and mobile source ROG and NOx emission categories. The updated forecasts 

were not compared to the corresponding forecasts in the 1994 AQMP because the emission 

inventory base years for each forecast set were different (1990 vs. 2002), as were the forecasting 

methodologies. Overall, ROG and NOx emissions are declining as they have for many years, 

continuing Ventura County’s progress towards meeting the state and federal ozone standards. 

This improvement in air quality is occurring despite growing population and motor vehicle usage. 

From a 2002 baseline, ROG emissions are expected to decline by 18.4 percent and NOx by 35.7 

percent by 2012. The greatest ROG and NOx declines will come from mobile sources, mostly a 

result of ARB’s mobile source control strategies. Except for the Electric Utilities category, which 

is expected to increase 24.3 percent by 2012, all other categories are expected to decline as well. 

8.4. Overall Progress 

The air quality indictors presented in Section 8.2, together with the ozone concentration declines 

presented in Section 1.5.1, and the emission trends in Section 8.3, indicate that Ventura County 

has made exceptional progress towards attaining the state 1-hour ozone standard. Such 

improvement will continue as new control strategies and programs presented in this plan for the 

federal 8-hour ozone standard are implemented. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 84 MAY 2008 

8.5. AQMP Control Measure and Rulemaking Update 

This section summarizes the District’s rulemaking activity for AQMP control measures during the 

2003 - 2005 triennial assessment period. This section does not include other rulemaking activities 

unrelated to AQMP control measures, such as rules for other air pollutants, administrative rule 

changes, rule language cleanups and fix-ups, and air permitting rules. Information regarding the 

District’s current rulemaking activities is available on the District’s Rule Development website. 

8.5.1. Control Strategy Cost Effectiveness

The CCAA requires that an emissions control strategy for the state 1-hour ozone standard be cost 

effective, when viewed in its entirety. Furthermore, the cost effectiveness of individual control 

measures must be determined and presented in rank order. The 1991 AQMP, prepared for the 

state 1-hour ozone standard, included cost effectiveness estimates for each proposed control 

measure. Only those control measures judged cost effective and technologically feasible for 

Ventura County were included in that plan. Such has been the case for every Ventura County 

AQMP before or since, including the 2007 AQMP. The proposed rule revisions included in this 

plan were based on multi-factor evaluations that included estimates of cost effectiveness. 

Likewise, District staff will not recommend any further study measure for adoption as a District 

rule unless shown to be cost effective and appropriate for Ventura County. 

8.5.2. Control Measures Amended or Implemented 2003 – 2005 & Control Measures 

Still Reducing Emissions Beyond the 2002 Emission Inventory Base Year

Table 8-3 presents those control measures adopted/amended during the triennial period and their 

respective emissions reductions beyond previous AQMP projections. Of all the control measures 

in Table 8-3, only R-328, Surface Cleaning & Degreasing, achieved significant emissions 

reductions in 2005. The other control measures in Table 8-3 produced only minimal reductions in 

2005. This reflects the maturity of the District’s clean air program. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 85 

Table 8-3 

Control Measures Adopted or Amended 2003 – 2005 

CM Rule 

Year 

Adopted/ Year 

Reduction 

(tons/summer day)

Number Control Measure Name Number Amended Implemented 2005 

ROG Control Measures 

R-306 Wood Products Coating 74.30 2003 2004 0.00a

R-328 Surface Cleaning & Degreasing 74.6/74.6.1b

 2003 2004 1.03 

R-314 Adhesives 74.20 2005 2005 0.02 

R-316 Graphic Arts Solvents 74.19 2003 2004 0.01 

R-501 Fiberglass & Polyester Resin 74.14 2005 2005 0.00 

R-504 Restaurant Cooking Operations 74.25 2004 2005 0.00 

 Total ROG Control Measures 1.06 

NOTES: a

 Data rounding may affect displayed values and totals. 

b Includes related revisions to District rules 74.12, 74.13, 94.19, 74.24, and 74.30. 

Data source: ARB Rule Reduction File (2/13/2007). 

8.5.3. Status of Control Measures Scheduled for Revision 2003 – 2005

Table 8-4 presents the status of control measures scheduled for adoption or revision during the 

2003 - 2005 triennial assessment period. The District implements each control measure in Table 

8-4 through a District rule adopted by the Ventura County Air Pollution Control Board (Board or 

APCB). This means that Board actions to adopt, revise, or repeal control measures are actually 

actions to adopt, revise, or repeal the associated District rules. 

Several of the proposed rule revisions were included to meet the “every feasible measure” 

requirement of the CCAA. Of those, the District’s board adopted revisions to two: R-306 (Rule 

74.30), Wood Product Coatings; and, R-501 (Rule 74.14), Polyester Resin Material Operations. 

Revisions to R-306 reduced certain ROC content limits to coincide with those in South Coast 

AQMD Rule 1171, Solvent Cleaning Operations. Revisions to R-501 lowered monomer content 

limits to match those in South Coast AQMD Rule 1162, Polyester Resin Operations. 

District staff’s “every feasible measure” analyses of control measures R-307 (Rule 74.12), 

Surface Cleaning of Metal Parts & Products, and R-328 (Rule 74.6), Surface Cleaning & 

Degreasing, indicated that each would achieve only negligible emission reductions. Therefore, 

the District did not adopt the proposed rule revisions. 

District staff also conducted detailed analyses of control measure R-419, Gasoline and ROG

Liquid Storage Degassing Operations (Rule 75.26 & 74.27) and concluded that the measure 

meets “every feasible measure.” 

The APCB did not adopt “every feasible measure” rule revisions for control measure R-316 (Rule 

74.19), Graphic Arts; and, R-324 (Rule 74.19.1), Screen Printing Operations, because District 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 86 MAY 2008 

staff’s analyses indicated that the proposed solvent limits would be technology forcing and 

infeasible at this time. 

The District’s board adopted further study control measure R-504, Restaurant Cooking 

Operations, as Rule 74.25. This new rule only applies to conveyorized restaurant charbroilers. 

Rule 74.25 will include other types of restaurant cooking equipment when control equipment 

becomes feasible and cost effective. 

Table 8-4 

Status of Control Measures Scheduled for Revision 2003 – 2005 

CM 

Number 

Control Measure 

Name Rule 

Affected Source 

Type Status/Comments 

R-306 Wood Products 

Coating 74.30 Wood product finishers 

Rule revisions adopted 6/06; <0.01 tpd ROC 

reduction. 

ROC limits reduced for surface preparations 

and cleanup to comply with “every feasible 

measure” requirement. 

R-307 

Surface Cleaning of 

Metal Parts & 

Products 

74.12 

Manufacturers and 

refinishers of metal parts 

and products 

Rule revision scheduled for 2008. 

Rule revision included to meet “every feasible 

measure” requirement. Rule not adopted due 

to only minor emission reductions expected 

and rulemaking workload considerations. 

R-311 

Motor Vehicle & 

Mobile Equipment 

Coating Operations 

74.18 Auto body shops 

Rule revision schedule to be determined. 

Rule revision included to meet “every feasible 

measure” requirement. Rule not adopted 

because ARB has adopted an SCM for 

automotive coatings and the District is 

evaluating the SCM for applicability in 

Ventura County. The SCM is included in the 

2007 AQMP as Further Study Measure R-311. 

R-316 Graphic Arts 74.19. Graphic arts operations 

Detailed analysis indicated that the technology 

forcing limits are not feasible at this time. 

Rule revision included to meet “every feasible 

measure” requirement. 

R-324 Screen Printing 

Operations 74.19.1 Screen printing 

operations 

Scheduled for reconsideration in 2008. 

Rule revision included to meet “every feasible 

measure” requirement. Detailed analysis 

indicated that the technology forcing limits are 

not feasible for Ventura County this time. 

R-328 Surface Cleaning & 

Degreasing 74.6 

Facilities that clean 

medical and electrical 

components 

Rule revisions to be determined. 

Rule revision included to meet “every feasible 

measure” requirement. Rule not adopted due 

to only minor emission reductions expected 

and rulemaking workload considerations. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 87 

Table 8-4 (continued) 

CM 

Number 

Control Measure 

Name Rule 

Affected Source 

Type Status/Comments 

R-419 

Crude Oil Storage 

Tank Degassing 

Operations 

74.26 Crude oil storage tanks 

Detailed analysis indicated the rule meets 

“every feasible measure.” 

Rule revisions included to meet “every feasible 

measure” requirement. 

R-419 

Gasoline & ROG 

Liquid Storage 

Degassing Operations 

74.27 

Gasoline & reactive 

organic compound liquid 

storage tanks 

Detailed analysis indicated the rule meets 

“every feasible measure.” 

Rule revisions included to meet “every feasible 

measure” requirement. Detailed analysis 

indicated the rule meets “every feasible 

measure.” 

R-501 Polyester Resin 

Material Operations 74.14 Polyester resin material 

operations 

Rule revisions adopted 4/05; <0.01 tpd ROC 

reduction. 

Rule revisions to meet “every feasible 

measure” requirement. Monomer content 

limits reduced and miscellaneous provisions 

revised or deleted. 

R-504 Restaurant Cooking 

Operations 74.25 Chain driven charbroilers 

Rule adopted 10/04; <0.02 tpd ROC 

Implements Further Study Measure R-504; 

only applies to conveyorized restaurant 

charbroilers. Other types of restaurant cooking 

equipment will be added when control options 

becomes feasible and cost-effective. 

R-606 Soil Decontamination 

Operations 74.29 Fuel-contaminated soils Rule scheduled for adoption in 2008. 

8.6. Every Feasible Measure 

Health and Safety Code Section 40914 requires plans for attaining the California 1-hour ozone 

standard to reduce emissions of ROG and NOx by a minimum of five percent per year, averaged 

over each consecutive three-year period. The 1991 Ventura County AQMP did not meet that 

emission reduction target. However, it was able to satisfy the alternative requirement of 

including “every feasible measure (also known as “all feasible measures”) . . . and an expeditious 

adoption schedule,” as allowed by Section 40914(b)(2). On August 13, 1992, the ARB approved 

the 1991 AQMP based on this “every feasible measure” determination of progress. 

District staff conducted “every feasible measure” assessments for the District’s 2001 and 2004 

Triennial Assessments. For the 2001 Triennial Assessment, District staff evaluated 25 stationary 

source categories contained in ARB’s document titled Identification of Achievable Performance 

Standards and Emerging Technologies for Stationary Sources. Based on that assessment, the 

District committed to further analysis of nine of the 25 measures. Of those measures, three were 

not implemented, four were recommended for adoption, one was not needed due to a lack of 

sources, and one required additional study. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 88 MAY 2008 

For the 2004 Triennial Assessment, staff compared District rules to the “Most Stringent All 

Feasible Measures List” contained in the California Air Pollution Control Officers Association 

Rules Subcommittee’s Potential All Feasible Measures Report (September 2003 Update). 

District staff examined 26 emission source categories and identified 13 categories where District 

rules had a potential for enhancement and further emission reductions. The District initiated 

rulemaking for each of the categories, during which the feasibility of each measure was 

determined for sources located in Ventura County. 

For this Triennial Assessment, staff evaluated 44 District rules by comparing them to rules of 

other California air districts. District staff identified eight rules with potential for enhancement 

(see Table 8-5). In addition, staff identified a potential new control measure, R-432, for oil well 

degassing operations. This new rule, if further evaluation shows it to be economically and 

technologically feasible in Ventura County, would control ROG emissions from venting natural 

gas from oil wellheads prior to repair work on the wells. The emission reduction potential is 

unknown at this time but could be significant. 

Of the measures listed in Table 8-5, the District’s Board, at its September 2007 meeting, 

determined that further enhancement of R-334 (Rule 74.30), Wood Products Coatings, is not cost 

effective and, hence infeasible. The basis for this conclusion is that the current emission limit 

exemptions in Rule 74.30 are already more stringent than those in South Coast AQMD Rule 

1136, Wood Products Coatings. Therefore, except for R-334, the District commits to rulemaking 

for the rules in Table 8-5, during which District staff will further evaluate the feasibility of each 

for Ventura County. Emission reductions will be estimated for those determined to be feasible 

prior to rule adoption. Staff believes that Ventura County APCD rules implement “every feasible 

measure” for all other emission source categories under its jurisdiction. 

Table 8-5 

Every Feasible/Further Study Control Measures – Detail 

CM 

Number 

District 

Rule Control Measure Description 

Rulemaking 

Schedule 

R-316 74.19 - Graphic Arts • Examine applicability of CTG recommended 

alcohol content limit for fountain solutions. 2008 

R-329 74.2 - Architectural 

Coatings

Adopt the statewide SCM that ARB amended in 

October 2007. TBD 

R-330 74.6 - Surface Cleaning 

and Degreasing

• Lower ROG limits for solvents used on 

electronics and electrical components, medical 

devices, and application equipment. 

• Remove PTI exemption, achieve compliance 

through back end controls. 

• Reexamine Rocketdyne exemption. 

• Remove ARB exemption. 

TBD 

R-331 74.6.1 - Batch Loaded 

Vapor Degreasers

• Limit vapor degreasing solvents to 25 grams of 

VOC per gallon. TBD 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 89 

Table 8-5 (continued) 

CM 

Number 

District 

Rule Control Measure Description 

Rulemaking 

Schedule 

R-332 a 74.12 - Surface Coating of 

Metal Parts and Products

• Implement a lower ROG limit for general 

air-dry one-component coatings.

• Create a new multi-component coating 

category.

• Eliminate the special category for lab 

furniture coatings.

• Limit the ROG content of spray gun and 

cleanup solvents to no more that 25 grams 

per liter.

2008 

R-311 

74.18 - Motor Vehicle & 

Mobile Equipment 

Coating Operations

Implement VOC coating limits per the ARB’s 

statewide SCM (10/20/05) and review the 

remainder of the SCM for feasibility in Ventura 

County. 

TBD b

R-334 c 74.30 - Wood Products 

Coating • Add ROG limits for refinishing operations. TBD 

R-431 70 - Storage and Transfer 

of Gasoline

Require: 

• Daily self-inspection. 

• Semi-annual source tests for stations with a 

throughput greater than 4.0 million gallons per 

year. 

• An O&M manual at each station. 

• 98% Phase I efficiency. 

TBD 

R-432 New - Oil Well Degassing Adopt a new rule to control ROG emissions from 

oil wells prior to repair work. TBD 

R-606 74.29 - Soil 

Decontamination

• Require submission and implementation of an 

approved mitigation plan. 

• Control emissions during transport of 

contaminated soil. 

• Treat or remove contaminated soil within 30 

days of excavation. 

• Change exemption threshold from 10 cu yd to 1 

cu yd contaminated soil. 

• Change exemption threshold for accidental 

spills from 1 bbl to 5 gallons. 

• Prohibit off-site aeration; if over 90 days 

treatment system may not emit >10 lb/day. 

• Active storage piles must be kept wet or 

covered. 

• Inactive piles must be covered within 1 hour. 

• Reexamine agricultural exemption. 

2008 

Various Various Coating Rules d Examine applicability of CTG recommendations 

regarding spray gun cleaning. 2008 

NOTES: a Control measure R-332 was adopted as a revision to District Rule 74.12, Surface Coating of Metal Parts and Product. b To be determined

c Control Measure-334 was rejected as enhancements to Rule 74.30, Wood Products Coatings based on cost effectiveness considerations. d District Rules 74.12, 74.13, 74.18, 74.21, 74.24, & 74.30.
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

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8.7. Control Measures Deleted from the 2007 AQMP 

Several control measures that were in the 1994 AQMP are not in the 2007 AQMP for either the 

federal 8-hour ozone standard or the state 1-hour ozone standard. Section 3.1.8 presents these 

measures. 

8.8. Ozone Transport 

The CCAA directs ARB to assess the contribution of ozone and ozone precursors in upwind 

basins or regions on ozone concentrations that violate the State ozone standard in downwind 

basins or regions. The movement of ozone and ozone precursors between basins or regions is 

termed transport. The CCAA also directs ARB to establish mitigation requirements for upwind 

districts commensurate with their contributions to the air quality problems in downwind basins or 

regions. 

Over the last decade, the ARB has published several transport reports that include technical 

assessments of transport relationships between air basins and regions in California. Along with 

these technical assessments, the reports have included mitigation requirements for ensuring that 

upwind areas do their part to limit the effects of transport on their downwind neighbors. These 

two important components are available on the following ARB websites: Transport Assessments

and Transport Mitigation. ARB completed its most recent transport assessment, Ozone Transport 

Mitigation in California, in 2004. 

ARB transport assessments indicate that Ventura County, as part of the South Central Coast Air 

Basin, impacts ozone levels in the South Coast Air Basin. This means that Ventura County must 

comply with ARB’s transport mitigation requirements. The District complies with these 

requirements through its rules and permitting programs, including adoption of “every feasible 

measure,” and application of BARCT to existing sources of ozone precursors. The county’s 

greatly improved air quality over the last twenty or so years provides direct evidence that Ventura 

County has and is mitigating ozone transport into the South Coast Air Basin. 

8.9. Public Information 

The District conducts a public information program through its Public Information Division. It 

does this through a variety of both traditional and innovative public information techniques 

including: 1) District website, 2) publications and creative materials, 3) educational programs, 4) 

outreach events, 5) advertising programs, 6) media relations, and 7) special projects. Further 

information regarding the District’s public information program is available on the District’s 

Public Information Division website. 

Publications and Creative Materials: In 2005, Public Information produced several new 

brochures, including: Give Us 20 Minutes; Air Quality Complaints (Spanish) and the booklet, 

The Book of Air. It also produced several new items for its educational program including an 

APCD hat for its Air Town elementary school program. In addition, it reprinted other previous 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 91 

publications including the 7 Days to Cleaner Air series. It also produced 12 issues of the monthly 

report, Skylines. 

Educational Programs: Public Information is actively involved in informing students about air 

pollution through outreach events and presentations. District staff has been educating middle 

school students with the Clean Air Quest classroom presentation since 2000. This interactive 

presentation includes a Jeopardy-style game that involves students with the links between air 

quality and transportation. Public Information also makes available Air Town, an activity 

program for children ages 5 – 9 in summer camps, day care centers, and after-school programs. 

Public Information also conducts educational events, including the Interactive Science Career

Expo, in conjunction with the Ventura County Science Fair. It also gives three Science Fair 

awards to air quality projects. Public Information has participated in the Ventura County clean 

air and transportation student calendar project for the last 12 years. Other air districts throughout 

the country have copied this concept. 

Clean Air Month Supplement: Public Information published the third Clean Air Today 

supplement in the Ventura County Star on May 1, 2005 to coincide with Clean Air Month. The 

supplement was distributed to subscribers of the publication. In addition, copies were distributed 

to the public at outreach events, classroom presentations, the District’s speakers bureau, and for 

Air Pollution Control Board use. The current edition of Clean Air Today is available on the 

District’s website. 

The supplement contains an update on Ventura County’s air from the Ventura County Air 

Pollution Control Officer; a letter from the former Secretary of the California Environmental 

Protection Agency; an article on hydrogen technology; information on the health effects of air 

pollution with an emphasis on children’s health; events calendar; book review; new EPA air 

pollution chart; article on early air quality pioneers; list of District publications and information 

on the speaker’s bureau; 2005 Asthma Walk information; air quality cartoon from the 60s; kid’s 

page; coupons from local merchants; and general contact information.

Summer Public Awareness Campaign: During the summer of 2005, the District partnered with 

the 24 Vons supermarkets in the county to distribute the “Don’t top off” postcards to their 

customers. Most of the postcards were distributed in three days. The District also distributed 

postcards through its Transportation Programs (Rule 211) section. 

Media Relations: Public Information handles media calls and news releases and provides local 

reporters with ideas for feature articles. Public Information coordinates all news conferences, 

radio and print interviews, and media sponsorships. 
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9. EMERGING ISSUES 

This chapter presents emerging air pollution issues that will provide the District with air pollution 

planning challenges well into the future. These issues are beyond the scope of the 2007 AQMP 

and are presented for informational purposes only. 

9.1. New Federal 8-hour Ozone Standard 

On March 12, 2008, EPA strengthened the national ambient air quality standards for ozone. The 

new federal primary 8-hour ozone standard, set to protect public health, is 0.075 ppm (rounded to 

the thousandth ppm). EPA also revised the federal secondary 8-hour ozone standard, set to 

protect public welfare, such as agricultural crops and ecosystems, to be identical to the primary 

standard. The former primary and secondary federal ozone standards, also identical at 0.08 ppm 

(effectively 0.084 ppm due to rounding), were last set in 1997. For comparison purposes, the 

California 8-hour ozone standard is 0.07 ppm. 

The revisions reflect new scientific evidence from more than 1,700 scientific studies showing that 

adverse public health effects occur at ozone levels below the former federal primary standard. 

Furthermore, other evidence now shows that natural vegetation and agricultural crops can be 

seriously damaged by repeated, low-level ozone exposure. 

EPA’s timeline for implementing the new federal ozone standards calls for EPA to designate 

areas attainment or nonattainment for the new standards by March 12, 2010. However, EPA may

take up to another year if there is insufficient data to make a designation by that date. Areas 

designated nonattainment would have until June 2013 to submit plans to EPA outlining how they 

would meet the new standards by specific dates (2013 - 2030), depending on the severity of their 

ozone problem. Until then, the 1997 federal 8-hour ozone standard and all associated regulatory 

requirements will remain in place. EPA’s preliminary projections indicate that Ventura County 

will not attain the new ozone standards before 2020. 

EPA’s Ground-level Ozone website contains more information regarding ozone and the new 

8-hour ozone standards. 

9.2. Climate Change 

The Earth's climate has undergone many changes during its history, ranging from ice ages to long 

periods of warmth. Historically, natural factors such as volcanic eruptions, changes in the Earth's 

orbit, and the amount of energy from the Sun have affected global temperatures and the Earth's 

climate. However, the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment 

Report, Climate Change 2007, states, “Global atmospheric concentrations of carbon dioxide, 

methane, and nitrous oxide have increased markedly as a result of human activities since 1750 

and now far exceed pre-industrial values determined from ice cores spanning many thousands of 

years. The global increases in carbon dioxide concentration are primarily due to fossil fuel use 

and land use change, while those of methane and nitrous oxide are primarily due to agriculture.” 

Moreover, according to the IPCC report, most of the observed increase in global average 
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temperatures since the mid-20th century is very likely due to the observed increase in 

anthropogenic concentrations of these three gases, collectively known as greenhouse gases 

(GHG). The IPCC report further states, “Warming of the climate system is unequivocal, as is 

now evident from observations of increases in global average air and ocean temperatures, 

widespread melting of snow and ice, and rising global average sea level.” 

Established in 1988 by the World Meteorological Organization and the United Nations 

Environment Programme, the IPCC is a scientific organization charged with evaluating the causes 

and risks of global climate change. The IPCC does not monitor climate change, nor does it 

conduct climate change research. Its primary purpose is to provide decision makers and other 

interested parties, including governments, industry, academia, and the public, with objective 

information on global climate change. It accomplishes its mission through periodic assessment 

reports, the most recent being the Fourth Assessment Report. The IPCC assessments are based on 

peer reviewed and published scientific literature and are considered authoritative. 

Climate change refers to any significant change in measures of climate (such as temperature, 

precipitation, or wind) lasting for an extended period (decades or longer) and can arise from 

natural factors and processes, as well as human activities. Global warming is an average increase 

in the temperature of the Earth's lower atmosphere called the troposphere and can contribute to 

changes in global climate patterns. Global warming can occur from a variety of causes, both 

natural and human induced. In common usage, global warming often refers to the warming that 

can occur because of increased emissions of greenhouse gases from human activities. 

Regarding the human influence on global climate change, the IPCC’s Working Group I Report, 

The Physical Science Basis, the first of four primary components of the Fourth Assessment 

Report, states: “Human activities contribute to climate change by causing changes in Earth’s 

atmosphere in the amounts of greenhouse gases, aerosols (small particles), and cloudiness. The 

largest known contribution comes from the burning of fossil fuels, which releases carbon dioxide 

gas to the atmosphere. 

Greenhouse gases and aerosols affect climate by altering incoming solar radiation and outgoing 

infrared (thermal) radiation that are part of Earth’s energy balance. Changing the atmospheric 

abundance or properties of these gases and particles can lead to a warming or cooling of the 

climate system. Since the start of the industrial era (about 1750), the overall effect of human 

activities on climate has been a warming influence. The human impact on climate during this era 

greatly exceeds that due to known changes in natural processes, such as solar changes and 

volcanic eruptions.” 

9.2.1. Climate Change Initiatives

Global warming is fast becoming the most important environmental issue of the 21st Century. As 

such, numerous local, state, national, and international efforts are gearing up and underway in the 

public and private sector to reduce GHG emissions. 
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9.2.2. United Nations Framework Convention on Climate Change 

The foremost international climate change initiative is the United Nations Framework Convention 

on Climate Change (UNFCCC), commonly known as the Kyoto Protocol. Signed on March 21, 

1994, the Kyoto Protocol calls for national governments to gather and share information on 

greenhouse gas emissions, national policies, and best practices; launch national strategies for 

addressing greenhouse gas emissions and adapting to expected impacts, including the provision of 

financial and technological support to developing countries; and cooperate in preparing for 

adaptation to the impacts of climate change. These efforts have been largely policy oriented. 

The Kyoto Protocol now covers more than 170 countries globally and more than 60 percent of 

countries in terms of global greenhouse gas emissions. As of December 2007, the only signatory 

nations not to have ratified the Kyoto Protocol are the United States and Kazakhstan. The treaty 

expires in 2012, and international talks began in May 2007 on a successor treaty. Further 

information regarding the UNFCCC and the Kyoto Protocol can be found on the UNFCCC

website. 

9.2.3. United States Climate Change Policy and Initiatives

Although the United States has not ratified the Kyoto Protocol, in 2002 it established a 

comprehensive policy to address climate change. The policy has three basic components: 

slowing the growth of emissions, strengthening science, technology, and institutions, and 

enhancing international cooperation. The federal government is implementing this policy through 

voluntary and incentive-based programs and has established major programs to advance climate 

technologies and improve climate science. Further information regarding climate change and the 

federal government’s climate change policy and initiatives can be found on EPA’s Climate 

Change website. 

9.2.4. California Climate Change Initiatives

Numerous California state and local agencies are developing policies, programs, and regulations 

to reduce California’s GHG emissions. Most notable and far reaching of these regulatory efforts 

is AB 32, The California Global Warming Solutions Act of 2006 (Health & Safety Code §38500 

et seq.). AB 32 establishes a comprehensive program of regulatory and market mechanisms to 

achieve real, quantifiable, and cost-effective reductions of GHG. More specifically, it makes 

ARB the primary state agency responsible for developing and maintaining a statewide inventory 

of GHG emissions and for formulating plans and action steps to reduce current GHG emissions 

statewide to 1990 GHG emission levels by the year 2020. AB 32 defines GHGs as carbon 

dioxide, methane, nitrous oxide, hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur 

hexafluoride. Further information regarding State of California climate change initiatives can be 

found on ARB’s Climate Change website and the State of California’s Climate Change Portal

website. Climate change activities and initiatives in Ventura County can be found on the County 

of Ventura’s Climate Change and Energy Conservation website. 
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GLOSSARY 

Activity Indicator: A measure of socioeconomic conditions relative to a base year, such as 

population, housing, and employment data, used to project future year emissions by the 

relationship of the related activity. Example: Natural gas use per household. 

Aerosols: Very small particles of solid or liquid matter suspended in the air. 

Air Basin: An area of the state designated by the California Air Resources Board pursuant to 

Subdivision (a) of Section 39606 of the CH&SC that has similar meteorological and geographic 

conditions. 

Air Contaminant: Any discharge, release, or other propagation into the atmosphere and 

includes but is not limited to, smoke, charred paper, dust, soot, grime, carbon, fumes, gases, 

odors, particulate matter, acids or any combination thereof. 

Air Monitoring: The periodic or continuous sampling and analysis of air pollutants in ambient 

air or from individual air pollutant sources. 

Air Quality Management District: A group or portions of counties, or an individual county 

specified in law with authority to regulate stationary, indirect, and area sources of air pollution 

with the region and governed by a regional air pollution control board comprised mostly of 

elected officials within the region.

Air Pollutants: Substances that are foreign to the atmosphere or are present in the natural 

atmosphere to the extent that they may result in adverse effects on humans, animals, vegetation, 

and/or materials. 

Air Pollution Control Board (APCB): The governing body for an air pollution control 

district. 

Air Pollution Control District (APCD): A county agency with authority to regulate sources 

of air pollution (other than emissions from mobile sources) such as refineries, manufacturing 

facilities, gasoline stations, dry cleaners, and power plants within a given county, and governed 

by a district Air Pollution Control Board composed of elected city and county officials. 

Air Pollution Control Officer (APCO): A person appointed by the APCB and given the 

authority to appoint district personnel for the purpose of observing and enforcing the provisions 

of Part 4, Division 26 of the CH&SC. 

Air Quality Management Plan (AQMP): A plan prepared by an APCD for a county or 

region designated nonattainment for one or more federal or state air pollutants, for the purpose of 
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bringing the area into compliance with the requirements of the federal and/or California ambient 

air quality standards. AQMPs are incorporated into the State Implementation Plan (SIP). 

Air Quality Standards: Those ambient air quality standards as promulgated by State or 

Federal pollution control agencies 

Ambient Air: Air occurring at a particular time and place outside of structures. Often used 

interchangeably with outdoor air. 

Anthropogenic: Of, relating to, or influenced by the impact of humans on nature; man-made. 

ARB: The state agency responsible for air pollution control in California. 

Area-wide Sources: Also known as “area” sources; are those sources which are not large 

enough to be tracked individually, but when added together can represent a large quantity of 

pollution. Examples of such sources include water heaters, gas furnaces, fireplaces, gas stations, 

dry cleaners and woodstoves. Area sources of pollution are identified by Category of Emission 

Source (CES) codes. 

Attainment: Achieving and maintaining one or more of the National and/or California Ambient 

Air Quality Standards (NAAQS or CAAQS). 

Atmosphere: The air that surrounds the earth but does not include the general volume of gases 

contained in any bona fide building. 

Attainment Area: A geographic area that complies with one or more of the NAAQS or 

CAAQS. 

Base Year: The year used in a predictive air pollution model that includes the known econmic 

conditions, population, and air emissions. The base year, current or past, is used to predict the 

forecast year in a predictive model.

Best Available Control Technology (BACT): The most up-to-date methods, systems, 

techniques, and production processes available to achieve the greatest feasible emission 

reductions for given regulated air pollutants and processes. BACT is a requirement of NSR (New 

Source Review) and PSD (Prevention of Significant Deterioration). 

Best Available Control Measure (BACM): A term used to describe the “best” measures 

(according to EPA guidance) for controlling small or dispersed sources of particulate matter and 

other emissions from sources such as roadway dust, woodstoves, and open burning. 
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Best Available Retrofit Control Technology (BARCT): An emission limitation that is 

based on the maximum degree of reduction achievable, taking into account environmental, 

energy, and economic impacts by each air pollutant source class or category (Section 40406 

CH&SC). 

Biogenic: Produced by living organisms. Biogenic air pollutant emissions are of great interest 

because of the predominance of agriculture and natural vegetation in Ventura County. However, 

the District has no authority to regulate biogenic emissions. Preliminary studies indicate that 

biogenic emissions may be at least two times the total hydrocarbon emissions already quantified 

in the emissions inventory for the AQMP. 

Bureau of Automotive Repair (BAR): An agency of the California Department of Consumer 

Affairs and responsible for the implementation of the motor vehicle inspection and maintenance 

program (smog check). 

California Air Resources Board (ARB): The State's lead air quality agency consisting of an 

eleven-member Governor-appointed board and supporting staff fully responsible for motor 

vehicle pollution control, and having oversight authority over California's air pollution 

management program. 

California Clean Air Act (CCAA): A California law passed in 1988 that provides the basis 

for air quality planning and regulation independent of federal regulations, and which establishes 

new authority for attaining and maintaining California’s air quality standards by the earliest 

practicable date. A major element of the Act is the requirement that local air districts in violation 

of the California clean air standards must prepare attainment plans that identify air quality 

problems, causes, trends, and actions to be taken for attainment. 

California Department of Transportation (Caltrans): A California state agency that 

oversees the state’s transportation infrastructure. 

California Emissions Inventory Development and Reporting System (CEIDARS): 

The state’s emissions inventory data base system.

California Emission Forecasting System (CEFS): ARB’s model to forecast air pollutant 

emissions. A major feature of the model is its ability to track the effects of emission control rules 

and growth activity for stationary and other mobile sources by linking these factors directly to the 

emission categories. 

California Environmental Quality Act (CEQA): A California law that sets forth a process 

for public agencies to make informed decisions on discretionary projects such land use 

entitlements. The process aids decision makers to determine whether any environmental impacts 

are associated with a proposed project. It requires elimination or reduction of environmental 
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impacts associated with a proposed project and the implementation of mitigation measures to 

reduce or remove those impacts. 

California Health and Safety Code (CH&SC): The California Health and Safety Code is 

the collection of state laws that govern, among other things, the handling of air pollution, 

hazardous waste, corrective action and permitted facilities.

Carbon Monoxide (CO): A colorless, odorless gas resulting from the incomplete combustion 

of fossil fuels. Over 80 percent of the CO emitted in urban areas is contributed by motor vehicles. 

CO is a criteria pollutant, and interferes with the blood's ability to carry oxygen to the body's 

tissues and results in numerous adverse health effects. 

City Urban Restriction Boundary (CURB): A regional boundary set in an attempt to 

control urbanization by designating the area inside the boundary for higher density urban 

development and the area outside for lower density rural development. 

Clean Air Act Amendments (CAAA): Amendments passed in 1977 and 1990 to the federal 

Clean Air Act of 1970 and which form the basis for the current national air pollution control 

effort. Basic elements of the amended act include national ambient air quality standards for major 

air pollutants, air toxics standards, acid rain control measures, and enforcement provisions. 

Compressed Natural Gas (CNG): An alternative fuel that is cleaner burning and helps to 

meet ARB's mobile and stationary emission standards. CNG may be used in place of less clean 

fuels for powering motor vehicles. 

Conformity: A formal demonstration of whether a federally-supported activity is consistent 

with the State Implementation Plan (SIP) – per section 176(c) of the federal CAA. Transportation 

conformity refers to plans, programs, and projects approved or funded by the Federal Highway 

Administration or the Federal Transit Administration. General conformity refers to projects 

approved or funded by other federal agencies. 

Consumer Products: Products such as detergents, cleaning compounds, polishes, personal 

care products, and automotive specialty products that are part of our everyday lives and, through 

consumer use, may contribute to air pollution. 

Contingency Measure: Required back-up air pollution control measures to be implemented in 

the event of specific conditions, such as failure to meet interim milestone emission reduction 

targets or failure to attain an applicable air quality standard by the statutory attainment date. Both 

the state and federal clean air acts require that District clean air plans include contingency 

measures.
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Control Efficiency (CE): A variable that estimates the technological efficiency of an air 

pollutant control strategy. Control efficiency is one of the variables used to develop a control 

factor. 

Control Factor (CF): Data derived from adopted State and Federal regulations and local 

district rules that impose emission reductions or a technological change on a particular emission 

process. Control factors are closely linked to the type of emission process and type of industry. 

They also account for three types of variables which include control efficiency, rule effectiveness, 

and rule penetration. 

Control Measure: A single measure in an air quality plan to maintain or reduce the emissions 

of criteria pollutants. Control measures are enforceable commitments in the air quality plan. 

Control Strategy: A combination of control measures designed to reduce air contaminant 

emissions to attain and maintain ambient air quality standards. 

Control Techniques Guidelines (CTG): Guidance documents issued by EPA designed to 

assist state and local pollution authorities to achieve and maintain air quality standards for certain 

air pollutant sources (e.g. organic emissions from solvent metal cleaning known as degreasing) 

through reasonably available control technologies (RACT). CTGs contain information on the 

economic and technological feasibility of available emission control techniques. 

Criteria Air Pollutant: An air pollutant for which acceptable levels of exposure can be 

determined and for which a federal or state ambient air quality standard has been set to protect 

public health and welfare. Examples include ozone, carbon monoxide, lead, nitrogen dioxide, 

sulfur dioxide, and fine particulates. 

Department of Motor Vehicles (DMV): The California state agency responsible for 

registering motor vehicle drivers and motor vehicles and collecting state and local motor vehicle 

fees. 

Department of Pesticide Regulation (DPR): The state agency responsible for regulating 

pesticide sales and use in California. 

Design Value: The pollutant concentration used by air quality managers as the basis for 

determining attainment of an air quality standard, generally by using an air quality model. The 

design value may or may not be the same as the designation value. 

District: A local air pollution control agency as defined by the CH&SC Section 40150. The 

Ventura County Air Pollution Control District is the local air pollution control agency for Ventura 

County, California. 
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EMFAC: The EMission FACtor computer model used by ARB to estimate on-road mobile 

vehicle emissions. This model is part of ARB’s overall on-road mobile source Mobile Vehicle 

Emission Inventory (MVEI) model. 

Early Progress Plan (EPP): An air quality planning document that shows progress towards 

attaining the federal ozone standards and establishes transportation conformity budgets. 

Emissions Data: Measured or calculated concentrations or weights of air contaminants 

emitted into the ambient air. Data used to calculate emissions data are not emissions data. 

Emission Factor: For stationary sources, the relationship between the amount of pollution 

produced and the amount of raw material processed or burned. For mobile sources, the 

relationship between the amount of pollution produced and the number of vehicle miles traveled. 

By using the emission factor of a pollutant and specific data regarding quantities of material used 

by a given source, it is possible to compute emissions for the source. 

Emission Offsets: Actual enforceable emission reductions from existing sources sufficient to 

offset anticipated emission increases associated with new or modified stationary sources. A rulemaking concept, whereby approval of a new stationary source of air pollution, or an increase of 

emissions from an existing source of air pollution, is conditional on the equal or greater reduction 

of emissions from other existing stationary sources of air pollution. This concept is utilized in 

addition to reduction in emissions by employing BACT. 

Emission Reduction Credit (ERC): Credits given for actual emission reductions that are 

real, enforceable, permanent, quantifiable, and surplus (beyond any required reductions). An actual 

credit is certified via a District-issued document that specifies the date of issuance, expiration date 

of credit, type of pollutant, and legal owner of emission reduction credits. In some cases, ERCs 

can be transferred to another owner or saved for future use. 

Emission Standard: The maximum amount or rate of a pollutant permitted from a polluting 

source such as an automobile or smoke stack. 

Emissions Inventory: An emissions inventory is a large dataset that, as a whole, describes 

emission sources and quantifies pollutants released into the atmosphere. Considerations that go 

into the inventory include type and location of emission sources, the processes involved, and the 

level of activity (day, month) and year of activity. 

Emissions Inventory Category: A group of similar air pollutant sources. Examples include 

oil and gas production, dry cleaning, and pesticide application. 

Emissions Inventory Code (EIC): State computer coding scheme (14 digits) used to 

categorize emissions in the CEIDARS database. 
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Environmental Protection Agency (EPA): The United States federal agency charged with 

protecting human health and safeguarding the natural environment upon which life depends. EPA 

promulgates national ambient air quality standards and implements federal programs to improve 

air quality. 

Equipment: Any operation, article, machine, equipment, or contrivance that may emit or reduce 

the emissions of any air contaminant or affected air pollutant. 

Exceedance: Measured concentration of an air pollutant in ambient air is higher than the state 

and/or federal ambient air quality standard for that pollutant. 

Expected Peak Day Concentration (EPDC): A calculated value that represents the 

concentration expected to occur at a particular air quality monitoring site once per year, on 

average. The calculation procedure uses measured data collected at the site during a three-year 

period. 

Federal Aviation Administration (FAA): An agency of the United States Department of 

Transportation with authority to regulate and oversee all aspects of civil aviation in the U.S. 

Federal Clean Air Act (CAA): A federal law passed in 1970 and significantly amended in 

1977 and 1990 that forms the basis for the national air pollution control efforts. Basic elements of 

the Act include national ambient air quality standards for major air pollutants, air toxics 

standards, acid rain control measures, and enforcement provisions. 

Federal Clean Air Act Amendments of 1990 (CAAA): The 1990 amended version of the 

federal CAA that mandates attainment of the NAAQS by specified attainment dates. 

Federal Highway Administration (FHA): A division of the United States Department of 

Transportation that specializes in highway transportation. The agency's major activities are 

grouped into two programs, The Federal-aid Highway Program and the Federal Lands Highway 

Program. 

Federal Implementation Plan (FIP): A plan prepared and enforced by the EPA that provides 

measures nonattainment areas must take to meet the requirements of the federal CAA. The EPA 

implements FIPs when states are unable or unwilling to adopt and implement adequate SIPs. 

Federal Motor Vehicle Control Program (FMVCP): All federal actions aimed at 

controlling pollution from motor vehicles by such efforts as establishing and enforcing tailpipe 

and evaporative emission standards for new vehicles, testing methods development, and guidance 

to states operating inspection and maintenance programs. 
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Federal Transit Administration (FTA): An agency within the United States Department of 

Transportation that provides financial and technical assistance to local public transit systems. 

Forecast Year: The future year of interest in a predictive air pollution or emissions model. 

The predictivie model results produce future year emissions based on expectations of future land 

use, transportation changes, econmic conditions, population growth, and emission controls.

GHG: Gaseous components of the atmosphere that contribute to the greenhouse effect. 

Greenhouse gases include, in order of relative abundance: water vapor, carbon dioxide, methane, 

nitrous oxide, ozone and chlorofluorocarbons. 

Growth Factor (GF): Data derived from county-specific economic activity profiles, population 

forecasts, and other socio-demographic activity. 

Heavy Duty Diesel Truck (HDD): Heavy duty diesel truck, gross vehicle weight 8,501-

33,000 pounds. 

Heavy-heavy Duty Diesel Truck (HHDD): Heavy-heavy duty diesel truck, gross vehicle 

weight greater than 33,001 pounds. 

Hydrocarbon (HC): Any of a large number of compounds containing various combinations of 

hydrogen and carbon atoms. They may be emitted into the air as a result of fossil fuel combustion 

and fuel volatilization, and are a major contributor to smog. 

Hydrofluorocarbons: A group of chemical compounds, consisting of alkanes, such as 

methane or ethane, with one or more halogens linked, such as chlorine or fluorine, making them a 

type of organic halide. 

Implementation Factor (IF): A variable used to develop control factors, indicating the 

relative amount of total control from a control measure occurring in a given year to account for 

phased implementation or control requirements occurring in tiers. 

Indirect Source: Any facility, building, structure, or installation, or combination thereof, 

which generates or attracts motor vehicle activity resulting in emissions of any pollutant (or 

precursor) for which there is a state or federal ambient air quality standard. Examples of indirect 

sources include employment sites, shopping centers, sports facilities, housing developments, 

airports, educational institutions, commercial and industrial developments, and parking lots and 

garages. 

Indirect Source Review (ISR): A rule or policy that attempts to reduce air emissions 

generated by buildings and facilities through the motor vehicle activity they generate or attract. 

Examples of such buildings and facilities include shopping centers, sports facilities, housing 
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developments, airports, educational institutions, commercial and industrial developments, and 

parking lots and garages. ISR is also called Indirect Source Control Program. 

Inspection and Maintenance Program (I & M): A motor vehicle inspection program 

implemented by the California Bureau of Automotive Repair. It is designed to ensure the 

effectiveness of their emission control systems on a biennial basis. The program was enacted in 

1979 and strengthened in 1990. The standard program is called Basic I & M. Enhanced I & M 

has more stringent testing requirements and is implemented in urbanized areas that are classified 

as “serious” and above nonattainment for ozone or “high moderate” and above for carbon 

monoxide and which had a population of 200,000 or more in 1980. Also known as the Smog 

Check program. 

Intergovernmental Panel on Climate Change (IPCC): A scientific body tasked to 

evaluate the risk of climate change caused by human activity. The panel was established in 1988 

by the World Meteorological Organization (WMO) and the United Nations Environment 

Programme (UNEP), two organizations of the United Nations. 

Internal Combustion Engine (IC): A heat engine in which the combustion generates the heat 

inside the engine proper instead of in a furnace. An example of an IC engine is an automobile 

engine. 

Inversion: A layer of warm air in the atmosphere that lies over a layer of cooler air, trapping 

pollutants beneath it. 

Lead: A gray-white metal that is soft, malleable, ductile, and resistant to corrosion. Sources of 

lead resulting in concentrations in the air include industrial sources and crustal weathering of soils 

followed by fugitive dust emissions. Health effects from exposure to lead include brain and 

kidney damage and learning disabilities. Lead is the only substance currently listed as both a 

criteria air pollutant and a toxic air contaminant. 

Local Agency Formation Commission (LAFCO): A decision making government entity in 

California with the responsibility to decide boundary issues pertaining to city and county (nonincorporated) lands, including spheres of influence, and issues about the annexation of county 

lands into a city or special district. 

Local Sources: Air pollution sources for which local governments (cities, counties, air 

agencies) have primary regulatory authority. 

Maintenance Plan: A plan that details the actions needed to maintain air quality at or below 

federal standards. The federal CAA requires maintenance plans for areas that have been redesignated attainment areas. 
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Major Source Category: A general, broad category of similar emission sources. Examples 

are Fuel Combustion, Waste Disposal, Solvent Evaporation are broad category classifications 

which are made up of many sub-categories. 

“Major” Sources under CAAA: A source with a potential to emit more than a specific 

threshold of emissions annually, determined by the nonattainment designation of an air quality 

district. 

Memorandum of Understanding (MOU): A formal agreement made among agencies for the 

purposes of jointly accomplishing a goal, program, etc. The governing boards of the involved 

agencies must ratify the agreement. 

Maximum Achievable Control Technology (MACT): The emission standard for sources of 

air pollution requiring the maximum reduction of hazardous emissions, taking cost and feasibility 

into account. Under the CAAA, MACT must not be less than the average emission level 

achieved by controls on the best performing 12 percent of existing sources, by category of 

industrial and utility sources. 

Metropolitan Planning Organization (MPO): The organization designated as being 

responsible, together with the State, for conducting the continuing, cooperative, and 

comprehensive planning process under 23 U.S.C. 134 and 49 U.S.C. 1607. It is the forum for 

cooperative transportation decision-making. 

Mobile Sources: Sources of air pollution such as automobiles, motorcycles, trucks, off-road 

vehicles, boats, and airplanes. 

Motor Vehicle: A self-propelled vehicle as defined in the California Vehicle Code, Division I, 

Section 415. 

National Ambient Air Quality Standards (NAAQS): Standards set by the EPA for the 

maximum levels of certain air pollutants in outdoor air without unacceptable effects on human 

health or public welfare. There are NAAQS for ozone, particulates, carbon monoxide, nitrogen 

dioxide, lead, and sulfur dioxide. 

Naval Base Ventura County: A major U.S. military facility in Ventura County, Califoria. 

New Source Review (NSR): The mechanism to assure that new and modified stationary 

sources of air pollution will not interfere with the attainment or maintenance of any ambient air 

quality standard, or prevent reasonable further progress towards the attainment or maintenance of 

any ambient air quality standard. A program used in a non-attainment area to permit or site new 

industrial facilities or modifications to existing industrial facilities that emit nonattainment criteria 
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air pollutants. The two major requirements of NSR are Best Available Control Technology and 

Emission Offsets. 

Nitrogen Dioxide (NO2): A reddish-brown gas with a characteristic sharp, biting odor. 

Nitrogen dioxide is one of the most prominent air pollutants and a poison by inhalation. 

Nonattainment Area: An area identified by the EPA and/or ARB as not meeting either federal 

or state clean air standards for a given criteria air pollutant. 

OFFROAD Emissions Model: California Air Resources Board model that estimates 

population, activity, and emissions for specific categories of off-road (non-highway) equipment 

by fuel types at the county level. 

Other Mobile Sources: A broad emissions category for mobile off-road equipment, including 

aircraft, locomotives, marine vessels, agricultural and construction equipment and more. 

Organic Solvents: Liquids containing organic compounds which are used as dissolvers, 

viscosity reducers, or cleaning agents. These liquids are principally derived from petroleum and 

include petroleum distillates, chlorinated hydrocarbons, chlorofluorocarbons, ketones, and 

alcohols. Solutions, emulsions, and dispersions of water and soap, or water and detergent are not 

organic solvents. Soaps and detergents are water-based surfactants.

Outer Continental Shelf (OCS): All submerged lands lying seaward of state coastal waters 

(beyond 3 miles offshore) which are under U.S. jurisdiction as defined by the Outer Continental 

Shelf Lands Act of 1953. 

Oxides of Nitrogen (NOx): A general term pertaining to compounds of nitric oxide (NO), 

nitrogen dioxide (NO2), and other oxides of nitrogen. Nitrogen oxides are created during 

combustion processes and are major contributors to smog formation and acid deposition. NO2 is 

a criteria pollutant and may result in numerous adverse human health effects. 

Ozone (O3): A reactive gas consisting of three oxygen atoms. Found in two layers of the 

atmosphere, the stratosphere and the troposphere. In the stratosphere (the atmospheric layer 7 to 

10 miles or more above the earth's surface), ozone is a natural form of oxygen that provides a 

protective layer shielding the earth from ultraviolet radiation. In the troposphere (the layer 

extending up 7 to 10 miles from the earth's surface), ozone is a chemical oxidant and major 

component of photochemical smog. It can seriously impair the respiratory system and is one of 

the most widespread of all the criteria pollutants for which the federal Clean Air Act required 

EPA to set standards. Ozone in the troposphere is produced through complex photochemical 

reactions of nitrogen oxides, which are among the primary pollutants emitted by combustion 

sources; hydrocarbons, released into the atmosphere through the combustion, handling and 

processing of petroleum products; and sunlight. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 108 MAY 2008 

Ozone Precursors: Chemicals such as volatile organic compounds and nitrogen oxides, 

occurring either naturally or as a result of human activities, which contribute to the formation of 

ozone, a major component of smog. 

Ozone Summer Season: May – October months, when ozone formation potential is the 

greatest. 

Particulate Matter (PM): Any material, except pure water, that exists in the solid or liquid 

state in the atmosphere. The size of particulate matter can vary from coarse, wind-blown dust 

particles, to fine particle combustion products. 

Particulate Matter - Fine (PM2.5): A mixture of very small atmospheric particles with an 

aerodynamic diameter equal to or less than 2.5 microns. PM2.5 consists of particles directly 

emitted into the air and particles formed in the air from the chemical transformation of gaseous 

pollutants. PM2.5 particles result from activities such as industrial and residential combustion, 

and from vehicle exhaust. Particles 2.5 microns or smaller infiltrate deepest portions of the lungs, 

increasing the risks of long-term disease, including chronic respiratory disease, cancer, and 

increased and premature death. 

Particulate Matter (PM10): A major air pollutant consisting of tiny solid or liquid particles of 

soot, dust, smoke, fumes, and mists. The size of the particles (10 microns or smaller, about 

0.0004 inches or less) allows them to easily enter the air sacs deep in the lungs where they may be 

deposited to result in adverse health effects. PM10 also causes visibility reduction and is a criteria 

air pollutant. 

parts per hundred million (pphm): Standard measurement of concentration by which ozone 

or other atmospheric gases are measured. 

parts per million (ppm): Standard measurement of concentration by which ozone or other 

atmospheric gases are measured. 

Perfluorocarbons: Compounds derived from hydrocarbons by replacement of hydrogen atoms 

by fluorine atoms and made up of carbon and fluorine atoms only, such as octafluoropropane, 

perfluorohexane and perfluorodecalin. 

Photochemical Reaction: A term referring to chemical reactions brought about by the light 

energy of the sun. Photochemical reactions in the atmosphere create harmful air pollutants such 

as ozone. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 109 

Point Source: Stationary emission sources having a district permit to operate identified on an 

individual basis due to the quantity or nature of their emissions. Examples of point sources 

include electrical power generating plants or large surface coating operations. 

Pesticide Use Reports (PUR): Pesticide Use Reports contain agricultural pesticide use 

information. Under the program, all agricultural pesticide use must be reported monthly to the 

county agricultural commissioner, who in turn, reports the data to DPR. 

Rate of Progress (ROP): Section 182(c)(2) of the federal CAA Amendments requires ozone 

nonattainment areas designated serious or above to demonstrate post-1996 volatile organic 

compound emission reductions of three percent per year, averaged over a 3-year period. The U.S. 

Environmental Protection Agency refers to these reductions as the rate-of-progress requirement. 

Reactive Fraction: The relative amount of Total Organic Gas (TOG) compounds which is 

photochemically reactive and participates in ozone formation, excluding methane and other 

compounds with inconsequential effects on ozone photochemical reactivity. 

Reactive Organic Gas (ROG): A reactive chemical gas composed of hydrocarbon 

compounds that may contribute to the formation of smog by their involvement in atmospheric 

chemical reactions. Also, sometimes referred to as non-methane organic compounds (NMOCs). 

VOC emissions are a subset of ROG emissions. 

Reasonably Available Control Measures (RACM): A broadly defined term referring to 

technologies and measures to control air pollution. 

Reasonably Available Control Technology (RACT): Devices, systems, process 

modifications, or other apparatus, or techniques that are reasonably available, taking into account 

the necessity of imposing such controls to attain and maintain a national ambient air quality 

standard; the social, environmental, and economic impact of such controls; and alternative means 

of providing for attainment and maintenance of such standard. 

Reasonable Further Progress (RFP): A requirement for a State Implementation Plan 

showing increments of progress (emission reductions) from the date of designation of 

nonattainment for federal ozone standards to the attainment dates - applicable for both Subpart 1 

and Subpart 2 ozone nonattainment areas. 

Regional Transportation Improvement Plan (RTIP): A staged, multiyear, intermodal 

program of transportation projects covering a metropolitan planning area, consistent with the 

metropolitan transportation plan, and developed pursuant to 23 CFR Part 450. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 110 MAY 2008 

Regional Transportation Plan (RTP): The official intermodal metropolitan transportation 

plan developed through the metropolitan planning process for the metropolitan planning area, and 

developed pursuant to 23 CFR Part 450. 

Reid Vapor Pressure (RVP): The absolute vapor pressure of volatile crude oil and volatile 

non-viscous petroleum liquids except liquefied petroleum gases as determined by American 

Society for Testing and Materials publication, “Test Method for Vapor Pressure of Petroleum 

Products.” 

Rule Effectiveness: An estimate of how well an air pollution rule or control strategy works in 

“real-world” application. Rule effectiveness is one of the variables used to develop a control 

factor. 

Rule Penetration: An estimate of the degree an air pollution control strategy will penetrate a 

certain regulated sector taking into account such things as equipment exemptions.

SAFETEA-LU: The Safe, Accountable, Flexible, Efficient Transportation Equity Act - A 

Legacy for Users was signed into law guaranteeing funding for federal transportation and transit 

programs through Fiscal Year 2009. SAFETEA-LU provides the funds and programmatic 

framework for maintaining and improving the nation’s transportation infrastructure. 

Save Open-Space and Agricultural Resources (SOAR): A local nonprofit citizen 

organization in Ventura County dedicated to making Ventura County a better place to live by 

limiting urban sprawl, protecting open space and agricultural lands, and promoting livable and 

sustainable communities in Ventura County. 

South Central Coast Air Basin (SCCAB): An air basin established by ARB that has similar 

meteorological and geographical conditions that consists of San Luis Obispo, Santa Barbara, and 

Ventura Counties. 

South Coast Air Quality Management District (SCAQMD): South Coast Air Quality 

Management District. A regional air quality control district encompassing four counties in 

Southern California (Los Angeles, Orange, Riverside and San Bernardino). 

Southern California Association of Governments (SCAG): The organization, known in 

federal law as the Council of Governments and Metropolitan Planning Organization, representing 

Los Angeles, Ventura, San Bernardino, Riverside, Orange, and Imperial Counties, and the cities 

within those six counties. As the designated Metropolitan Planning Organization for the 

designated areas, the Association of Governments is mandated by the federal government to 

research and formulate plans for transportation, growth management, hazardous waste 

management, and air quality. Additional mandates exist at the state level. 
 FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE 111 

Smog: A combination of smoke, ozone, hydrocarbons, nitrogen oxides, and other chemically 

reactive compounds, which, under various conditions of weather and sunlight, may result in a 

murky brown haze that causes adverse health effects and human welfare effects. A primary 

source of smog is motor vehicles. 

Smog Check Program: A motor vehicle inspection program implemented by the California 

Bureau of Automotive Repair. It is designed to ensure the effectiveness of automobile emission 

control systems on a biennial basis. The program was enacted in 1979 and strengthened in 1990. 

Also known as the Inspection and Maintenance Program (I & M). 

State Implementation Plan (SIP): A document prepared by each state describing existing air 

quality conditions and measures that it will take to attain and maintain national ambient air 

quality standards. The provisions and commitments in SIPs are federally enforceable. 

State Tidelands: The off-shore region three miles from the shoreline. 

Stationary Sources: Non-mobile sources such as power plants, refineries, and manufacturing 

facilities, and turbines that emit air pollutants. 

Suggested Control Measure (SCM): “Model rules” adopted by the California Air 

Resources Board to help California’s air districts develop their respective clean air rules and meet 

air quality standards. SCMs also promote uniformity among rules in each air district.

Sulfur Dioxide (SO2): A colorless, extremely irritating gas or liquid of sulfur and oxygen and 

whose chemical formula is SO2. Sulfur dioxide mainly enters the atmosphere as a pollutant 

through burning high sulfur-content fuel oils and coal, and from chemical processes occurring at 

chemical plants and refineries. SO2 is a criteria air pollutant. 

Summer Planning Day Emissions: Emissions occurring during a typical summer day 

during the months of May – October. This term is interchangeable term with “ozone season” day 

emissions. 

tons per day (tpd): A unit of measurement often used in air pollutant emission inventories.

Total Organic Compounds (TOC): Organic compounds of carbon including methane 

emitted to the atmosphere. TOCs exclude carbon monoxide, carbon dioxide, carbonic acid, 

metallic carbides or carbonates and ammonium carbonate. 

Transportation Control Measure (TCM): Any control measure or strategy to reduce vehicle 

trips, vehicle use, vehicle miles traveled, vehicle idling, or traffic congestion for the purpose of 

reducing motor vehicle emissions. TCMs include encouraging the use of carpools and mass 

transit. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE 112 MAY 2008 

Transportation Planning Agency (TPA): See Regional Transportation Planning Agency. 

United Nations Framework Convention on Climate Change (UNFCCC): An 

international environmental treaty produced at the United Nations Conference on Environment 

and Development (UNCED), informally known as the Earth Summit, held in Rio de Janeiro in 

1992. The treaty is aimed at reducing emissions of greenhouse gases in order to combat global 

warming. 

United States Environmental Protection Agency (EPA): The United States agency 

charged with setting policy and guidelines, and carrying out legal mandates for the protection of 

national interests in environmental resources. 

Vehicle Miles Traveled (VMT): A measure of both the volume and extent of motor vehicle 

operation; the total number of vehicle miles traveled within a specified geographical area over a 

given period of time. 

Ventura County Transportation Commission (VCTC): Agency responsible for planning 

and funding transportation and transit improvements in Ventura County. VCTC develops and 

implements transportation policies, projects, and funding priorities for a wide variety of 

transportation projects. 

Visibility: The distance that atmospheric conditions allow a person to see at a given time and 

location. Visibility reduction from air pollution is often due to the presence of sulfur and nitrogen 

oxides, as well as particulate matter, including aerosols. 

Volatile Organic Compounds (VOC): Hydrocarbon compounds that exist in the ambient air. 

VOCs contribute to the formation of smog and/or may themselves be toxic. VOCs often have an 

odor, and examples include gasoline, alcohol, and paint solvents. 

Weight of Evidence (WOE): A supplementary set of analyses intended to verify modeled 

predictions of future air quality, especially at levels near the federal standards. These analyses 

can include air quality trends, emission trends, meteorological data, evaluation of other air quality 

indicators, and additional air quality modeling. 
Appendix A 

Ventura County 

Transportation Control Measure Commitments 

MAY 2008 

PAGE A-1

Lead Agency Project ID Description 

Camarillo VEN050403 Calleguas Bike Path - Construct Class I Bike Path for 0.7 Miles from Adolfo Road to th

Route 101 Freeway, with Connection to New Trail at Village at the Park (Phase II) 

Camarillo VEN990305 Construct Ponderosa Extension from Earl Joseph to Ventura Blvd & Ventura Blvd Extension from Ponderosa to East of Central Ave including Bike Lanes Fillmore VEN051401 Route 126 and Santa Paula Branch Railroad at Pole Creek – Class I Bike Path Undercrossing 0.2 Miles in Length Ojai VEN010203 Ojai Valley Bike Trail Extension/Fulton St Extension Ojai VEN54164 Bicycle & Pedestrian Trail Extension: Fox Cyn Barranca from Rt 150 to Ojai Valley TraOxnard VEN990317 Oxnard Blvd 5th/Vineyard & on 5th St (Rt 34) Oxnard Blvd/Rose Ave Construct New Bi

& Pedestrian Facilities 

San Buenaventura VEN031229 Route 126 Bike Path – Phase II Bike Path (Class I) Crossing the Harmon Barranca San Buenaventura VEN061007 Mills Road at Maple Adjacent to Pacific View Mall – Bus Turnouts with Bus Shelters, a

Other Bus Stop Amenities 

San Buenaventura VEN990319 California St Bridge over Rt 101 Pedestrian Enhancements 
PAGE A-2 

MAY 2008

Lead Agency Project ID Description 

Santa Paula VEN54168 Facility Incl Bikeway/Walkway from Santa Paula Creek to Peck Rd Fencing, Landscap

Bridge & Drainage, Public Access Points/Safety Items 

Simi Valley VEN031202 Simi Valley Transit Expansion to Serve New Mall – Demonstration Project Simi Valley VEN031203 One (1) CNG Paratransit Van for Expansion Simi Valley VEN031205 Simi Valley Bike Path Class I 500-Foot Connection from Hidden Ranch Road to Stear

Street Includes 75-Foot Tunnel Under Metrolink Tracks 

Simi Valley VEN051201 West Los Angeles Ave from West City Limit to Easy Street Class II Bike Lanes Simi Valley VEN055401 Expand Transit Maintenance Facility to Accommodate System Expansion Simi Valley VEN055408 Automatic Vehicle Location and Data Terminals Simi Valley VEN055410 One Expansion Paratransit Van Simi Valley VEN055413 One Expansion Paratransit Van 
MAY 2008 

PAGE A-3

Lead Agency Project ID Description 

Simi Valley VEN54051 In Simi Valley Arroyo Simi Bike Trail from End of Existing Trail to Corriganville Park Construct Bike Path and Lanes South Coast Area Transit VEN057403 Downtown Ventura/Ventura Harbor Demonstration Service (3-Year Demonstration) Thousand Oaks VEN011209 Construct Bikeway Adjacent to Rt 101 (South Side) from Rancho Rd to Willow Ln (TEA

#221) 

Thousand Oaks VEN030613 Electronic Fare Boxes for Thousand Oaks Transit Thousand Oaks VEN030614 Thousand Oaks Transportation Center Operations Building & Customer Waiting Room including Landscaping, Outdoor Seating, and Security Lighting Thousand Oaks VEN031212 Expand Traffic Signal Coordination System Thousand Oaks VEN054605 Conejo Creek Park Bike Path – Class I Bike Path for 0.5 Miles in Conejo Creek Park f

Route 23 to Janss Road 

Thousand Oaks VEN056407 Hillcrest Drive from Teller Road to Conejo Blvd – Class II Bike Lanes Ventura County VEN070101 Phase 2 – Santa Paula Branch Row – Piru Creek to Rte 126, Construct Class I Bike P

and Pedestrian Path with Grading on Entire Row (Split from VEN990310) 
PAGE A-4 

MAY 2008

Lead Agency Project ID Description 

Ventura County VEN990310 Piru/Rancho Camulos Construct Class I Bike Path and Adjacent Pedestrian Path, Fen

Re-Lay Track, Install Platform at Rancho Camulos 

Ventura County Transportation Commission 

VEN070204 Smartcard Upgrade 

Ventura County Transportation Commission 

VEN93017 Regional Rideshare Program 

Source: Adopted 2006 Regional Transportation Improvement Program with Amendments 1-12, Southern California Association of Gove

Draft 2008 Regional Transportation Plan, Southern California Association of Governments, December 2007.
Appendix B 

Ventura County Reasonably Available 

Control Measures Analysis 

Appendix B - Ventura County Reasonably Available Control Measures Ana

Page B-1

Measure No. Measure Title Description Feasible for Use in VC? Reasoned Justification for Infeasi

Section 108(f) 1. Programs For Improved Public Transit 

1.1 Regional Express Bus Program Purchase of buses to operate regional express bus services. yes 1.2 Transit Access to Airports Operation of transit to airport to serve air passengers. no The measure is economically infeasible b

not enough air passengers in Ventura Co

1.3 Study Benefits of a Particulate Trap Retrofit Program 

Examine potential to accelerate application of particulate traps on diesel-powered buses to achieve earlier compliance with State regulations. 

yes 

1.4 Major Expansion of Mass Transit Major change to the scope and service levels. no 

The measure is economically infeasible bnot enough transit demand for order of mincreases in spending. 

1.5 Expansion of Public Transportation Systems Expand and enhance existing public transit services. yes 1.6 

Transit Service Improvements in Combination with Park-and-Ride Lots and Parking Management 

Local jurisdictions and transit agency improve the public transit system and add new Park-andRide facilities and spaces on an as needed basis. 

yes 

1.7 Free transit during special events 

Offer free transit during selected special events to reduce event-related congestion and associated emission increases. 

no 

The Legislature reduced authority to implsource control measures through revisionSafety Code (HSC 40717.6, HSC 40717.40717.9). 

1.8 

Require that government employees use transit for home to work trips, expand transit, and encourage large businesses to promote transit use 

Require all government employees use transit a specified number of times per week. no 

The Legislature reduced authority to implsource control measures through revisionSafety Code (HSC 40717.6, HSC 40717.40717.9). 

1.9 Increase parking at transit centers or stops Encourage transit convenience by providing additional parking at transit centers. yes 

1.10 Expand regional transit connection ticket distribution Provides interchangeability of transit ticket. yes 
Appendix B - Ventura County Reasonably Available Control Measures Analysis (

Page B-2

Measure No. Measure Title Description Feasible for Use in VC? Reasoned Justification for Infeasi

Section 108(f) 2. Restriction Of Certain Roads Or Lanes To, Or Construction Of Such Roads Or Lanes For Use By, Passenger Buses Or High Occup

2.1 Update High Occupancy Vehicle (HOV) Lane Master Plan 

Analysis of increased enforcement, increasing occupancy requirements, conversion of existing HOV lanes to bus only lanes and/or designation of any new carpool lanes as bus-only lanes; utilization of freeway shoulders for peak-period express bus use; commercial vehicle buy-in to HOV lanes; and appropriateness of HOV lanes for corridors that have considered congestion pricing or value pricing. 

no The measure is technologically infeasible 

is no existing HOV Lane Plan. 

2.2 Fixed Lanes for Buses and Carpools on Arterials Provide fixed lanes for buses and carpools on arterial streets where appropriate. no The measure is economically infeasible b

County has no long, congested corridors

2.3 

Expand number of freeway miles available, allow use by alternative fuel vehicles, changes to HOV lane requirements and hours 

Various measures evaluated in many ozone nonattainment areas. Specifics vary according to freeway system, use patterns and local characteristics. 

no 

There are no existing HOV lanes in Ventu

process includes an evaluation for HOV tregion and includes or excludes HOV lantransportation and performance criteria. 
Appendix B - Ventura County Reasonably Available Control Measures Analysis (

Page B-3

Measure No. Measure Title Description Feasible for Use in VC? Reasoned Justification for Infeasi

Section 108(f) 3. Employer-Based Transportation Management Plans, including incentives 

3.1 Commute Solutions 

The federal law that complements parking cashout is called the Commuter Choice Program. It provides for benefits that employers can offer to employees to commute to work by methods other than driving alone. 

yes 

3.2 Parking Cash-Out 

State law requires certain employers who provide subsidized parking for their employees to offer a cash allowance in lieu of a parking space. 

yes 

3.3 Employer Rideshare Program Incentives 

Employer rideshare incentives and introduction of strategies designed to reduce single occupant vehicle trips. Examples include: public awareness campaigns, Transportation Management Associations among employers, alternative work hours, financial incentives for TCM participants as well as tax breaks for employers. 

yes 

3.4 Implement Parking Charge Incentive Program 

Evaluate feasibility of an incentive program for cities and employers that convert free public parking spaces to paid spaces. Review existing parking polices as they relate to new development approvals. 

no 

This measure is technologically infeasible is plenty of parking, there would be little ereduction benefit, and it would unfairly pebusinesses. 

3.5 Preferential Parking for Carpools and Vanpools 

This measure encourages public and private employers to provide preferential parking spaces for carpools and vanpools to decrease the number of single occupant automobile work trips. The preferential treatment could include covered parking spaces or nearby spaces. 

yes 

3.6 Employee Parking Fees Encourage public and private employers to charge employees for parking. no 

The measure is technologically infeasible region is not urbanized enough to make icould have negative effect to public parkiparking). 
Appendix B - Ventura County Reasonably Available Control Measures Analysis (

Page B-4

Measure No. Measure Title Description Feasible for Use in VC? Reasoned Justification for Infeasi

Section 108(f) 3. Employer-Based Transportation Management Plans, including incentives (continued) 

3.7 Merchant Transportation Incentives 

Implement “non-work” trip reduction ordinances requiring merchants to offer customers mode shift travel incentives such as free bus passes and requiring owners/managers/developers of large retail establishments to provide facilities for non-motorized modes. 

no 

The Legislature reduced authority to impl

source control measures through revisionSafety Code (HSC 40717.6, HSC 40717.40717.9). 

3.8 Purchase vans for vanpools Purchase a specified number of vans for use in employee commute travel. yes 3.9 

Encourage merchants and employers to subsidize the cost of transit for employees 

Provide outreach and possible financial incentives to encourage local employers to provide transit passes or subsidies to encourage less individual vehicle travel. 

yes 

3.10 Off-days for ozone alerts just like sick days 

On ozone alert days, notify employees through email that there is an ozone alert. Employees are given a pre-specified number of days they can decide not to come in to work on ozone forecast days. 

no 

The Legislature reduced authority to impl

source control measures through revisionSafety Code (HSC 40717.6, HSC 40717.40717.9). 

3.11 Pay for in-house meals on ozone action days Employer pays for meals in-house on ozone alert days so that employees do not travel to off- site locations. no The Legislature reduced authority to impl

source control measures through revisionSafety Code (HSC 40717.6, HSC 40717.40717.9). 

3.12 Voluntary business closures on ozone action days A more expensive version of “off-days” for ozone alerts. no 

The Legislature reduced authority to impl

source control measures through revisionSafety Code (HSC 40717.6, HSC 40717.40717.9). 

3.13 Close government offices on Ozone action days to serve as an example Similar to voluntary business closures. no 

The Legislature reduced authority to impl

source control measures through revisionSafety Code (HSC 40717.6, HSC 40717.40717.9). 

3.14 Mandatory compressed work weeks Self-explanatory. no 

The Legislature reduced authority to impl

source control measures through revisionSafety Code (HSC 40717.6, HSC 40717.40717.9). 
Appendix B - Ventura County Reasonably Available Control Measures Analysis (

Page B-5

Measure No. Measure Title Description Feasible for Use in VC? Reasoned Justification for Infeasi

Section 108(f) 3. Employer-Based Transportation Management Plans, including incentives (continued) 

3.15 Telecommuting Goal of specified percentage of employees telecommuting at least once per week. no 

The Legislature reduced authority to impl

source control measures through revisionSafety Code (HSC 40717.6, HSC 40717.40717.9). 

Section 108(f) 4. Trip Reduction Ordinance In December 1995, Congress changed the Clean Air Act Amendments to make the Employee Commute Option program voluntary (no longer mandatory). Ca

employer based trip reduction ordinance programs (SB437). Therefore, no mandatory programs can be imposed. 
Appendix B - Ventura County Reasonably Available Control Measures Analysis (

Page B-6

Measure No. Measure Title Description Feasible for Use in VC? Reasoned Justification for Infeasi

Section 108(f) 5. Traffic Flow Improvement Programs That Achieve Emission Reductions 

5.1 Develop Intelligent Transportation Systems A variety of technological applications intended to produce more efficient use of existing transportation corridors. Yes 5.2 Coordinate Traffic Signal Systems 

This measures implements and enhances synchronized traffic signal systems to promote steady traffic flow at moderate speeds. 

Yes 

5.3 Reduce Traffic Congestion at Major Intersections 

This measure implements a wide range of traffic control techniques designed to facilitate smooth, safe travel through intersections: signalization, turn lanes, median dividers, grade separations. 

yes 

5.4 Site-Specific Transportation Control Measures 

This measure could include geometric or traffic control improvements at specific congested intersections or at other substandard locations. Another example might be programming left turn signals at certain intersections to lag, rather than lead, the green time for through traffic. 

yes 

5.5 Removal of On-Street Parking Require all commercial/industrial development to design and implement off-street parking. no 

The Legislature reduced authority to impl

source control measures through revisionSafety Code (HSC 40717.6, HSC 40717.40717.9). 

5.6 Reversible Lanes Implement reversible lanes on arterial streets to improve traffic flow where appropriate. no The measure is technologically infeasible 

is not sufficient congestion. 

5.7 One-Way Streets 

Redesignate streets (or portions of in downtown areas) as one-way to improve traffic flow where appropriate. 

no The measure is technologically infeasible 

is not sufficient congestion. 

5.8 On-Street Parking Restrictions Restrict on-street parking where appropriate. no 

The Legislature reduced authority to impl

source control measures through revisionSafety Code (HSC 40717.6, HSC 40717.40717.9). 

5.9 Bus Pullouts in Curbs for Passenger Loading Provide bus pullouts in curbs, or queue jumper lanes for passenger loading and unloading. yes 
Appendix B - Ventura County Reasonably Available Control Measures Analysis (

Page B-7

Measure No. Measure Title Description Feasible for Use in VC? Reasoned Justification for Infeasi

Section 108(f) 5. Traffic Flow Improvement Programs That Achieve Emission Reductions (continued) 

5.10 Additional Freeway Service Patrol 

Operation of additional lane miles of new roving tow truck patrols to clear incidents and reduce delay on freeways during peak periods. 

no Current and projected congestion levels t

measure. 

5.11 

Consider coordinating scheduling of arterial and highway maintenance to exclude ozone action days if the maintenance activities require lane reductions on heavily utilized arterials and highways 

Self-explanatory. yes 

5.12 Re-routing of trucks on ozone days Self-explanatory. yes 5.13 Fewer stop signs Improve flow-through traffic by removing stop signs. no The measure is technologically infeasible 

safety issue outweighs the potential smabenefit. 

5.14 Ban left turns 

Banning all left turns would stop the creation of bottlenecks although slightly increase travel distances. 

no No clear demonstration of air quality bene

5.15 Changeable lane assignments 

Increase number of one-way lanes going in congested flow direction during peak traffic hours. 

no Not enough congestion on applicable fac

appreciable air quality improvement. 

5.16 Adaptive traffic signals and signal timing Self explanatory. yes 5.17 Freeway bottleneck improvements (add lanes, construct shoulders, etc.) Identify key freeway bottlenecks and take accelerated action to mitigate them. yes 5.18 

Minimize impact of construction on traveling public. Have contractors pay when lanes are closed as an incentive to keep lanes open 

Self-explanatory. yes 

5.19 Internet provided road and route information Reduce travel on highly congested roadways by providing accessible information on congestion and travel. yes 5.20 Regional route marking systems to encourage underutilized capacity Encourage travel on local roads and arterials by better route marking to show alternatives. yes 
Appendix B - Ventura County Reasonably Available Control Measures Analysis (

Page B-8

Measure No. Measure Title Description Feasible for Use in VC? Reasoned Justification for Infeasi

Section 108(f) 5. Traffic Flow Improvement Programs That Achieve Emission Reductions (continued) 

5.21 Congestion management field team to clear incidents Self-explanatory. no Current and projected congestion levels t

measure. 

5.22 Use dynamic message signs to direct/smooth speeds during incidents Self-explanatory. yes 5.23 Get real-time traffic information to drivers Self-explanatory. yes 5.24 55 mph speed limit during ozone season Self-explanatory. no The measure is not feasible because it re

legislative change. 

5.25 Require 40 mph speed limit on all facilities Depends on area’s emission factors. no The measure is not feasible because it re

legislative change. 

5.26 Require lower speeds during peak periods Self-explanatory. no The measure is not feasible because it re

legislative change. 

Section 108(f) 6. Fringe And Transportation Corridor Parking Facilities Serving Multiple Occupancy Vehicle Programs Or Transit Service 

6.1 Park and ride lots 

Develop, design and implement new Park and Ride facilities in locations where they are needed. 

Yes 

6.2 Park and ride lots serving perimeter counties Specific to a locality. Yes 
Appendix B - Ventura County Reasonably Available Control Measures Analysis (

Page B-9

Measure No. Measure Title Description Feasible for Use in VC? Reasoned Justification for Infeasi

Section 108(f) 7. Programs To Limit Or Restrict Vehicle Use In Downtown Areas Or Other Areas Of Emission Concentration Particularly During Per

7.1 Off-Peak Goods Movement 

Implement an ordinance to restrict truck deliveries by time or place in order to minimize traffic congestion during peak periods. 

no No authority to implement. 

7.2 Truck Restrictions During Peak Periods 

Implement an ordinance to restrict truck travel during peak periods in order to minimize traffic congestion. 

no No authority to implement. 

7.3 Involve school districts to encourage walking to school Decrease vehicle emissions due to school trips by reducing these trips through education and out-reach programs. yes 7.4 

Adjust school hours so they do not coincide with peak traffic periods and Ozone seasons 

Measure to reduce travel during peak periods and ozone-contributing periods in the early morning. 

no No authority to implement. 

7.5 Area-wide tax for parking Reduce driving by limiting parking through pricing measures. no No authority to implement. 7.6 Increase parking fees Same as above. no No authority to implement. 7.7 Graduated pricing starting with highest in CBD Charge the most for parking in the central business or other high volume areas in a city to discourage vehicle travel in these areas. no No authority to implement. 7.8 Buy parking lots and convert to other land use Limit parking by converting available parking to other land uses to discourage driving. no The measure is technologically infeasible 

area is too rural to be able to make this e

7.9 

Limit the number of parking spaces at commercial airlines to support mass transit 

Reduce airport travel by limits on parking at airports. no 

The measure is technologically infeasible the discretion of regional and local airpormake land use decisions pertaining to air

7.10 No CBD vehicles unless LEV or alt fuel or electric Define high-use area and ticket any vehicles present unless they are low emitting, alternative fueled or electric. no No authority to implement. 7.11 Auto restricted zones 

No vehicles allowed in certain areas where high emissions, congestion or contribution to ozone problems. 

no No authority to implement. 

7.12 Incentives to increase density around transit centers Lower travel by increasing residential and commercial density in areas near transit. yes 7.13 Land use/air quality guidelines Guidelines for development that contributes to air quality goals. yes 
Appendix B - Ventura County Reasonably Available Control Measures Analysis (

Page B-10

Measure No. Measure Title Description Feasible for Use in VC? Reasoned Justification for Infeasi

Section 108(f) 7. Programs To Limit Or Restrict Vehicle Use In Downtown Areas Or Other Areas Of Emission Concentration Particularly During Per

7.14 Incentives for cities with good development practices Provide financial or other incentive to cities that practice air quality-sensitive development. yes 7.15 Cash incentives to foster jobs/housing balance Specific to locality – encouraged by California Clean Air Plan. yes 7.16 Trip reduction oriented development Specific to locality – encouraged by California Clean Air Plan. yes 7.17 Transit oriented development Specific to locality – encouraged by California Clean Air Plan. yes 7.18 Sustainable development Specific to locality – encouraged by California Clean Air Plan. yes 
Appendix B - Ventura County Reasonably Available Control Measures Analysis (

Page B-11

Measure No. Measure Title Description Feasible for Use in VC? Reasoned Justification for Infeasi

Section 108(f) 8. Programs For The Provision Of All Forms Of High-Occupancy, Shared-Ride Services 

8.1 Financial Incentives, Including Zero Bus Fares 

Provide financial incentives or other benefits, such as free or subsidized bus passes and cash payments for not driving, in lieu of parking spaces for employees who do not drive to the workplace. 

yes 

8.2 Internet ridematching services 

Provide match-lists, route info, hours and contact information over the internet to assist individuals in joining or developing carpools. 

yes 

8.3 Preferential parking for carpoolers Provide free, covered, near-building or similar incentives to carpoolers. yes 8.4 Credits and incentives for carpoolers Self-explanatory. yes 8.5 

Employers provide vehicles to carpoolers for running errands or emergencies 

Having vehicles available for work-day errands makes it easier to go to work without one. yes 

8.6 Subscription Services 

Free van services to provide transportation for the elderly, handicapped or other individuals who have no access to transportation. 

yes 

8.7 School carpools Self-explanatory. no 

The Legislature reduced authority to impl

source control measures through revisionSafety Code (HSC 40717.6, HSC 40717.40717.9). 

8.8 Guaranteed ride home Self-explanatory. yes 
Appendix B - Ventura County Reasonably Available Control Measures Analysis (

Page B-12

Measure No. Measure Title Description Feasible for Use in VC? Reasoned Justification for Infeasi

Section 108(f) 9. Programs To Limit Portions Of Road Surfaces Or Certain Sections Of The Metropolitan Area To The Use Of Non-Motorized VehicleTime And Place 

9.1 Establish Auto Free Zones and Pedestrian Malls Establish auto free zones and pedestrian malls where appropriate. yes 9.2 Encouragement of Pedestrian Travel 

This measure involves encouraging the use of pedestrian travel as an alternative to automobile travel. Pedestrian travel is quite feasible for short shopping, business, or school trips. Promotion of pedestrian travel could be included in air pollution public awareness efforts to remind people of this basic alternative. 

yes 

9.3 Bicycle/Pedestrian Program Fund high priority projects in countywide plans consistent with funding availability. yes 9.4 Close certain roads for use by non- motorized traffic During special events, weekends, or certain times of the day, close some roads to all but non-motorized traffic. yes 9.5 Encouragement of Bicycle Travel 

Promotion of bicycle travel to reduce automobile use and improve air quality. Bikeway system planning, routes for inter-city bike trips to help bicyclists avoid other, less safe facilities. Another area for potential actions is the development and distribution of educational materials, regarding bicycle use and safety. 

yes 

9.6 Free Bikes 

Provide free bikes in the manner of Boulder, CO. Simple utilitarian bikes that can be used throughout the metro area and dropped off at destination for use by anyone desiring use. 

no 

No authority to implement. Also, evidencbicycle theft is a problem in other programthis measure technically and economical

9.7 Cash Rebates for Bikes Provide financial incentives to purchase bicycles and thereby encourage use. no No clear demonstration of air quality bene9.8 Close streets for special events for use by bikes and pedestrians Self-explanatory. yes 
Appendix B - Ventura County Reasonably Available Control Measures Analysis (

Page B-13

Measure No. Measure Title Description Feasible for Use in VC? Reasoned Justification for Infeasi

Section 108(f) 10. Programs For Secure Bicycle Storage Facilities And Other Facilities, Including Bicycle Lanes, For The Convenience And ProtectPrivate Areas 

10.1 Bike racks at work sites Self explanatory. yes 10.2 Bike Racks on Buses 

Bike racks would be placed on a to-bedetermined number of buses to increase bicycle travel. 

yes 

10.3 Regional Bike Parking Ordinance for all new construction 

Bike Transit Centers for/at all employment centers 100+ employees: Bike lockers, clothing lockers, showers, cleaners drop-off and pick-up. 

Bike repair and rental. 

no 

The Legislature reduced authority to impl

source control measures through revisionSafety Code (HSC 40717.6, HSC 40717.40717.9). 

Section 108(f) 11. Programs To Control Extended Idling Of Vehicles 

11.1 Limit Excessive Car Dealership Vehicle Starts 

Require car dealers to limit the starting of vehicles for sale on their lot(s) to once every two 

weeks. Presently, a number of new and used car dealers start their vehicles daily to avoid batter failure and assure smooth start-ups for customer test drives. 

no 

The measure is technologically infeasible to colder climates where vehicles are stabasis, vehicles in the South Central Coasless frequently. 

11.2 Limitations on Vehicle Idling Limitations to limit extended idling operations of trucks. yes 11.3 Turn off engines while stalled in traffic Public outreach or police-enforced program. no The measure raises safety and congestio

has no clear demonstration of air quality 

11.4 Restrict idling Require idle limits for trucks. yes 11.5 Reduced idling at drive-throughs. Shut windows down Mandate no idling or do not allow drive-through windows during ozone season. no No clear demonstration of air quality emis

This measure is not economically feasibl

11.6 Promote use of Pony engines 

Use special battery engines to keep air conditioning and other truck systems working while truck not in use. 

yes 

11.7 Idle restrictions at airport curbsides Police enforced. no No commercial airport. This measure is 

on security restrictions. 
Appendix B - Ventura County Reasonably Available Control Measures Analysis (

Page B-14

Measure No. Measure Title Description Feasible for Use in VC? Reasoned Justification for Infeas

Section 108(f) 12. Program To Reduce Motor Vehicle Emissions, Consistent With Title II, Which Are Caused By Extreme Cold Start Conditions The definition of an "extreme cold start" specifies temperatures below 20 degrees Fahrenheit. Not applicable in the South Central Coast - no extreme cold staSection 108(f) 13. Employer-Sponsored Programs To Permit Flexible Work Schedules 

13.1 Alternative Work Schedules 

Enables workers to choose their own working hours within certain constraints. Flextime provides the opportunity for employees to use public transit, ridesharing, and other nonmotorized transportation. A related strategy, 

staggered work hours, is designed to reduce peak congestion in the vicinity of the workplace. 

yes 

13.2 Modifications of Work Schedules 

Implement alternate work schedules that flex the scheduled shift time for employees. Encourage the use of flexible or staggered work hours to promote off-peak driving and accommodate the use of transit and carpooling. 

yes 

13.3 Telecommunications-Telecommuting Encourage the use of telecommuting in place of motor vehicle use where appropriate. yes 13.4 Telecommunications-Teleconferencing Encourage the use of teleconferencing in place of motor vehicle use where appropriate. yes 
Appendix B - Ventura County Reasonably Available Control Measures Analysis (

Page B-15

Measure No. Measure Title Description Feasible for Use in VC? Reasoned Justification for Infeas

Section 108(f) 14. Programs And Ordinances To Facilitate Non-Automobile Travel, Provision And Utilization Of Mass Transit, And To Generally RedVehicle Travel, As Part Of Transportation Planning And Development Efforts Of A Locality, Including Programs And Ordinances Applicable To New And Other Centers Of Vehicle Activity 

14.1 Areawide Public Awareness Programs 

This measure focuses on conducting ongoing public awareness programs throughout the year to provide the public with information on air pollution and encourage changes in driving behavior and transportation mode use. 

yes 

14.2 Special Event Controls 

This measure would require new and existing owners/operators of the special event centers to reduce mobile source emissions generated by their events. A list of optional strategies would be available that reduce mobile source emissions. The definition of “special event center” could be developed through the rule development process. 

yes 

14.3 Land Use/Development Alternatives 

This measure includes encouraging land use patterns which support public transit and other alternative modes of transportation. In general, this measure would also encourage land use patterns designed to reduce travel distances between related land uses (e.g., residentialcommercial). Shorter trip lengths ultimately relieve traffic congestion and improve air quality. 

yes 

14.4 Voluntary No Drive Day Programs 

Conduct voluntary no drive day programs during the ozone season through media and employer based public awareness activities. 

yes 

14.5 

Evaluation of the Air Quality Impacts of New development and Mitigation of Adverse Impacts 

Evaluate the air quality impacts of new development and mitigate any adverse impacts. yes 

14.6 Transportation for Livable Communities (TLC)/Housing Incentive Program 

Program provides planning grants, technical assistance, and capital grants to help cities and nonprofit agencies define and implement transportation projects that support community plans including increased housing near transit. 

no Too little funding available to implement a

14.7 Incentives to increase density around transit centers Lower travel by increasing residential and commercial density in areas near transit. yes 
Appendix B - Ventura County Reasonably Available Control Measures Analysis (

Page B-16

Measure No. Measure Title Description Feasible for Use in VC? Reasoned Justification for Infeas

Section 108(f) 14. Programs And Ordinances To Facilitate Non-Automobile Travel, Provision And Utilization Of Mass Transit, And To Generally RedVehicle Travel, As Part Of Transportation Planning And Development Efforts Of A Locality, Including Programs And Ordinances Applicable To New And Other Centers Of Vehicle Activity (continued) 

14.8 Incentives for cities with good development practices Provide financial or other incentive to local cities that practice air quality-sensitive development. yes 14.9 Increase state gas tax Self-explanatory. no No authority to implement and no clear d

quality benefits. 

Section 108 (f) 15. Programs For New Construction And Major Reconstructions Of Paths, Tracks Or Areas Solely For The Use By Pedestrian Or OtTransportation When Economically Feasible And In The Public Interest. For Purposes Of This Clause, The Administrator Shall Also Consult With T

15.1 Encouragement of Pedestrian Travel Promote public awareness and use of walking as an alternative to the motor vehicle. yes 15.2 Pedestrian and Bicycle Overpasses Where Safety Dictates Ongoing implementation as development occurs. yes 

Section 108(f) 16. Program To Encourage The Voluntary Removal From Use And The Marketplace Of Pre-1980 Model Year Light Duty Vehicles And 

16.1 

Counties assess ten dollar license plate fee to fund repair/replacement program for high-emitters 

Self-explanatory. no No authority to implement. 

16.2 Buy vehicles older than 1975 Self-explanatory. yes 16.3 Demolish impounded vehicles that are high emitters Self-explanatory. no No authority to implement. 16.4 

Do whatever is necessary to allow cities to remove the engines of high emitting vehicles (pre-1980) that are abandoned and to be auctioned 

Self-explanatory. no No authority to implement. 

16.5 Accelerated retirement program Identify high emitting vehicle age groups and develop a program to remove them from use. yes 
Appendix C 

Ventura County Emissions Forecast by 

Emissions Inventory Category Name 

FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE C-1 

Table C-1 

ROG Planning Emission Forecast by Summary Category 

by Air Basin 

Ventura County ROG (tons/summer day) 

EIC Summary Category Name 2002 2008 2011 2012 

SCC AIR BASIN 

STATIONARY SOURCES 

Fuel Combustion 

010-Electric Utilities 0.24 0.29 0.30 0.30 

020-Cogeneration 0.01 0.01 0.01 0.01 

030-Oil And Gas Production (Combustion) 0.14 0.13 0.13 0.13 

040-Petroleum Refining (Combustion) 0.00 0.00 0.00 0.00 

050-Manufacturing And Industrial 0.04 0.04 0.04 0.04 

052-Food And Agricultural Processing 0.20 0.20 0.20 0.20 

060-Service And Commercial 0.07 0.08 0.08 0.08 

099-Other (Fuel Combustion) 0.07 0.04 0.03 0.03 

Total Fuel Combustion 0.76 0.78 0.78 0.78 

Waste Disposal 

110-Sewage Treatment 0.01 0.01 0.01 0.01 

120-Landfills 0.09 0.11 0.12 0.13 

130-Incinerators 0.00 0.00 0.00 0.00 

140-Soil Remediation 0.00 0.00 0.00 0.00 

199-Other (Waste Disposal) 0.00 0.00 0.00 0.00 

Total Waste Disposal 0.09 0.12 0.13 0.13 

Cleaning And Surface Coatings 

210-Laundering 0.01 0.01 0.01 0.01 

220-Degreasing 3.17 2.27 2.38 2.41 

230-Coatings And Related Process Solvents 2.08 2.19 2.28 2.31 

240-Printing 0.27 0.28 0.29 0.29 

250-Adhesives And Sealants 0.40 0.39 0.41 0.41 

299-Other (Cleaning And Surface Coatings) 0.38 0.39 0.41 0.42 

Total Cleaning And Surface Coatings 6.30 5.53 5.78 5.85 

Petroleum Production And Marketing 

310-Oil And Gas Production 2.03 1.97 1.93 1.92 

320-Petroleum Refining 0.00 0.00 0.00 0.00 

330-Petroleum Marketing 1.07 1.03 1.04 1.05 

399-Other (Petroleum Production And Marketing) 0.00 0.00 0.00 0.00 

Total Petroleum Production And Marketing 3.10 3.00 2.97 2.97 

Industrial Processes 

410-Chemical 0.10 0.11 0.11 0.11 

420-Food And Agriculture 0.01 0.01 0.01 0.01 

430-Mineral Processes 0.04 0.04 0.04 0.04 

440-Metal Processes 0.00 0.00 0.00 0.00 

450-Wood And Paper 0.11 0.11 0.12 0.12 

470-Electronics 0.02 0.02 0.03 0.03 

499-Other (Industrial Processes) 0.08 0.08 0.08 0.08 

Total Industrial Processes 0.37 0.38 0.40 0.40 

TOTAL STATIONARY SOURCES 10.62 9.81 10.06 10.14 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE C-2 MAY 2008 

Table C-1 (continued) 

Ventura County ROG (tons/summer day) 

EIC Summary Category Name 2002 2008 2011 2012 

AREA-WIDE SOURCES 

Solvent Evaporation 

510-Consumer Products 5.78 5.06 5.21 5.26 

520-Architectural Coatings And Related Process 

 Solvents 3.21 2.87 2.97 3.01 

530-Pesticides/Fertilizers 3.99 4.82 4.82 4.82 

540-Asphalt Paving / Roofing 0.56 0.60 0.62 0.63 

Total Solvent Evaporation 13.53 13.36 13.62 13.71 

Miscellaneous Processes 

610-Residential Fuel Combustion 0.20 0.21 0.22 0.22 

620-Farming Operations 0.12 0.12 0.12 0.12 

630-Construction And Demolition 0.00 0.00 0.00 0.00 

640-Paved Road Dust 0.00 0.00 0.00 0.00 

645-Unpaved Road Dust 0.00 0.00 0.00 0.00 

650-Fugitive Windblown Dust 0.00 0.00 0.00 0.00 

660-Fires 0.02 0.02 0.02 0.02 

670-Managed Burning And Disposal 0.19 0.21 0.21 0.21 

690-Cooking 0.07 0.06 0.06 0.06 

Total Miscellaneous Processes 0.59 0.61 0.63 0.63 

TOTAL AREA-WIDE SOURCES 14.12 13.97 14.25 14.34 

 

MOBILE SOURCES 

On-Road Motor Vehicles 

710-Light Duty Passenger (LDA) 9.19 5.11 3.88 3.53 

722-Light Duty Trucks - 1 (LDT1) 1.84 1.14 0.89 0.84 

723-Light Duty Trucks - 2 (LDT2) 3.64 2.55 2.35 2.28 

724-Medium Duty Trucks (MDV) 1.87 1.32 1.25 1.23 

732-Light Heavy Duty Gas Trucks - 1 (LHDV1) 1.39 0.57 0.47 0.45 

733-Light Heavy Duty Gas Trucks - 2 (LHDV2) 0.21 0.10 0.09 0.09 

734-Medium Heavy Duty Gas Trucks (MHDV) 0.51 0.25 0.20 0.18 

736-Heavy Heavy Duty Gas Trucks (HHDV) 0.20 0.11 0.08 0.07 

742-Light Heavy Duty Diesel Trucks - 1 (LHDV1) 0.00 0.02 0.02 0.02 

743-Light Heavy Duty Diesel Trucks - 2 (LHDV2) 0.02 0.02 0.01 0.01 

744-Medium Heavy Duty Diesel Trucks (MHDV) 0.04 0.03 0.03 0.03 

746-Heavy Heavy Duty Diesel Trucks (HHDV) 0.37 0.32 0.27 0.25 

750-Motorcycles (MCY) 0.86 1.00 0.92 0.91 

760-Heavy Duty Diesel Urban Buses (UB) 0.00 0.00 0.00 0.00 

762-Heavy Duty Gas Urban Buses (UB) 0.01 0.01 0.01 0.01 

770-School Buses (SB) 0.02 0.01 0.02 0.02 

776-Other Buses (OB) 0.03 0.02 0.02 0.02 

780-Motor Homes (MH) 0.11 0.06 0.04 0.04 

Total On-Road Motor Vehicles 20.31 12.64 10.54 9.98 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE C-3 

Table C-1 (continued) 

Ventura County ROG (tons/summer day) 

EIC Summary Category Name 2002 2008 2011 2012 

Other Mobile Sources 

810-Aircraft 0.51 0.66 0.69 0.69 

820-Trains 0.13 0.12 0.12 0.11 

830-Ships And Commercial Boats 0.23 0.26 0.27 0.27 

840-Recreational Boats 3.85 3.65 3.42 3.37 

850-Off-Road Recreational Vehicles 2.00 2.65 2.89 2.98 

860-Off-Road Equipment 5.90 4.90 4.24 4.05 

870-Farm Equipment 0.77 0.59 0.51 0.46 

890-Fuel Storage And Handling 1.21 0.79 0.62 0.58 

Total Other Mobile Sources 14.59 13.61 12.74 12.52 

TOTAL MOBILE SOURCES 34.90 26.24 23.29 22.50 

 

ERC Balance 1.67 1.67 1.67 

TOTAL SCC AIR BASIN 59.64 51.69 49.26 48.65 

OCS AIR BASIN 

STATIONARY SOURCES 

Fuel Combustion 

030-Oil And Gas Production (Combustion) 0.01 0.01 0.01 0.01 

060-Service And Commercial 0.02 0.02 0.02 0.02 

Total Fuel Combustion 0.03 0.04 0.04 0.04 

Cleaning And Surface Coatings 

230-Coatings And Related Process Solvents 0.01 0.00 0.00 0.00 

Total Cleaning And Surface Coatings 0.01 0.00 0.00 0.00 

Petroleum Production And Marketing 

310-Oil And Gas Production 0.04 0.04 0.04 0.04 

330-Petroleum Marketing 0.00 0.00 0.00 0.00 

Total Petroleum Production And Marketing 0.04 0.04 0.04 0.04 

TOTAL STATIONARY SOURCES 0.09 0.08 0.08 0.08 

 

MOBILE SOURCES 

Other Mobile Sources 

810-Aircraft 0.07 0.10 0.11 0.11 

830-Ships And Commercial Boats 0.56 0.64 0.67 0.68 

Total Other Mobile Sources 0.63 0.74 0.78 0.79 

TOTAL MOBILE SOURCES 0.63 0.74 0.78 0.79 

 

TOTAL OCS AIR BASIN 0.72 0.82 0.86 0.87 

TOTAL VENTURA COUNTY 60.36 52.51 50.12 49.52 

NOTES:

Source: CEFS v1.06 (November 2006). 

External ARB adjustments to CEFS v1.06 are noted in Table 4-3. 

Table 3-7 State proposed 2012 reductions are not included. 

Data rounding may affect displayed values and totals. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE C-4 MAY 2008 

Table C-2 

NOx Planning Emission Forecast by Summary Category 

by Air Basin 

Ventura County NOx (tons/summer day) 

EIC Summary Category Name 2002 2008 2011 2012 

SCC AIR BASIN 

STATIONARY SOURCES 

Fuel Combustion 

010-Electric Utilities 1.36 1.62 1.68 1.69 

020-Cogeneration 0.01 0.01 0.02 0.02 

030-Oil And Gas Production (Combustion) 0.23 0.21 0.21 0.20 

040-Petroleum Refining (Combustion) 0.01 0.01 0.01 0.01 

050-Manufacturing And Industrial 0.85 0.89 0.93 0.95 

052-Food And Agricultural Processing 2.54 2.34 2.17 2.11 

060-Service And Commercial 0.36 0.33 0.33 0.33 

099-Other (Fuel Combustion) 0.52 0.34 0.30 0.29 

Total Fuel Combustion 5.88 5.75 5.64 5.59 

Waste Disposal 

110-Sewage Treatment 0.01 0.01 0.01 0.01 

120-Landfills 0.08 0.10 0.11 0.11 

130-Incinerators 0.00 0.00 0.00 0.00 

140-Soil Remediation 0.00 0.00 0.00 0.00 

199-Other (Waste Disposal) 0.00 0.00 0.00 0.00 

Total Waste Disposal 0.09 0.11 0.12 0.12

Cleaning And Surface Coatings 

210-Laundering 0.00 0.00 0.00 0.00 

220-Degreasing 0.00 0.00 0.00 0.00 

230-Coatings And Related Process Solvents 0.00 0.00 0.00 0.00 

240-Printing 0.00 0.00 0.00 0.00 

250-Adhesives And Sealants 0.00 0.00 0.00 0.00 

299-Other (Cleaning And Surface Coatings) 0.00 0.00 0.00 0.00 

Total Cleaning And Surface Coatings 0.00 0.00 0.00 0.00

Petroleum Production And Marketing 

310-Oil And Gas Production 0.04 0.03 0.03 0.03 

320-Petroleum Refining 0.00 0.00 0.00 0.00 

330-Petroleum Marketing 0.00 0.00 0.00 0.00 

399-Other (Petroleum Production And Marketing) 0.00 0.00 0.00 0.00 

Total Petroleum Production And Marketing 0.04 0.03 0.03 0.03 

Industrial Processes 

410-Chemical 0.00 0.00 0.00 0.00 

420-Food And Agriculture 0.00 0.00 0.00 0.00 

430-Mineral Processes 0.00 0.00 0.00 0.00 

440-Metal Processes 0.02 0.02 0.02 0.02 

450-Wood And Paper 0.00 0.00 0.00 0.00 

470-Electronics 0.00 0.00 0.00 0.00 

499-Other (Industrial Processes) 0.06 0.06 0.06 0.06 

Total Industrial Processes 0.08 0.08 0.08 0.08 

TOTAL STATIONARY SOURCES 6.08 5.97 5.87 5.82 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE C-5 

Table C-2 (continued) 

Ventura County NOx (tons/summer day) 

EIC Summary Category Name 2002 2008 2011 2012 

AREA-WIDE SOURCES 

Solvent Evaporation 

510-Consumer Products 0.00 0.00 0.00 0.00 

520-Architectural Coatings And Related Process 

 Solvents 0.00 0.00 0.00 0.00 

530-Pesticides/Fertilizers 0.00 0.00 0.00 0.00 

540-Asphalt Paving / Roofing 0.00 0.00 0.00 0.00 

Total Solvent Evaporation 0.00 0.00 0.00 0.00

Miscellaneous Processes 

610-Residential Fuel Combustion 1.12 1.16 1.17 1.18 

620-Farming Operations 0.00 0.00 0.00 0.00 

630-Construction And Demolition 0.00 0.00 0.00 0.00 

640-Paved Road Dust 0.00 0.00 0.00 0.00 

645-Unpaved Road Dust 0.00 0.00 0.00 0.00 

650-Fugitive Windblown Dust 0.00 0.00 0.00 0.00 

660-Fires 0.00 0.01 0.01 0.01 

670-Managed Burning And Disposal 0.15 0.15 0.16 0.16 

690-Cooking 0.00 0.00 0.00 0.00 

Total Miscellaneous Processes 1.27 1.32 1.34 1.35 

TOTAL AREA-WIDE SOURCES 1.27 1.32 1.34 1.35 

 

MOBILE SOURCES 

On-Road Motor Vehicles 

710-Light Duty Passenger (LDA) 6.41 3.27 2.41 2.16 

722-Light Duty Trucks - 1 (LDT1) 1.64 0.91 0.69 0.63 

723-Light Duty Trucks - 2 (LDT2) 5.11 2.91 2.41 2.24 

724-Medium Duty Trucks (MDV) 2.94 1.86 1.59 1.49 

732-Light Heavy Duty Gas Trucks - 1 (LHDV1) 2.26 1.09 0.96 0.95 

733-Light Heavy Duty Gas Trucks - 2 (LHDV2) 0.30 0.20 0.19 0.19 

734-Medium Heavy Duty Gas Trucks (MHDV) 0.50 0.33 0.28 0.26 

736-Heavy Heavy Duty Gas Trucks (HHDV) 0.53 0.31 0.23 0.21 

742-Light Heavy Duty Diesel Trucks - 1 (LHDV1) 0.04 0.75 0.60 0.56 

743-Light Heavy Duty Diesel Trucks - 2 (LHDV2) 0.75 0.58 0.48 0.45 

744-Medium Heavy Duty Diesel Trucks (MHDV) 3.20 2.06 1.68 1.55 

746-Heavy Heavy Duty Diesel Trucks (HHDV) 5.40 4.37 3.48 3.18 

750-Motorcycles (MCY) 0.14 0.23 0.23 0.23 

760-Heavy Duty Diesel Urban Buses (UB) 0.07 0.07 0.06 0.06 

762-Heavy Duty Gas Urban Buses (UB) 0.02 0.02 0.03 0.03 

770-School Buses (SB) 0.17 0.14 0.15 0.15 

776-Other Buses (OB) 0.09 0.08 0.07 0.07 

780-Motor Homes (MH) 0.43 0.33 0.27 0.26 

Total On-Road Motor Vehicles 30.00 19.52 15.80 14.67
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE C-6 MAY 2008 

Table C-2 (continued) 

Ventura County NOx (tons/summer day) 

EIC Summary Category Name 2002 2008 2011 2012 

Other Mobile Sources 

810-Aircraft 0.33 0.45 0.48 0.48 

820-Trains 2.46 1.72 1.30 1.32 

830-Ships And Commercial Boats 1.35 1.54 1.57 1.59 

840-Recreational Boats 0.89 1.26 1.24 1.24 

850-Off-Road Recreational Vehicles 0.05 0.06 0.07 0.07 

860-Off-Road Equipment 15.61 12.73 10.88 10.30 

870-Farm Equipment 3.81 2.97 2.58 2.40 

890-Fuel Storage And Handling 0.00 0.00 0.00 0.00 

Total Other Mobile Sources 24.49 20.73 18.13 17.41 

TOTAL MOBILE SOURCES 54.49 40.25 33.93 32.07 

 

ERC Balance 0.51 0.51 0.51 

TOTAL SCC AIR BASIN 61.83 48.05 41.65 39.75 

OCS AIR BASIN 

STATIONARY SOURCES 

Fuel Combustion 

030-Oil And Gas Production (Combustion) 0.15 0.14 0.14 0.14 

060-Service And Commercial 0.24 0.26 0.27 0.27 

Total Fuel Combustion 0.39 0.40 0.41 0.41 

Cleaning And Surface Coatings 

230-Coatings And Related Process Solvents 0.00 0.00 0.00 0.00 

Total Cleaning And Surface Coatings 0.00 0.00 0.00 0.00 

Petroleum Production And Marketing 

310-Oil And Gas Production 0.01 0.01 0.01 0.01 

330-Petroleum Marketing 0.00 0.00 0.00 0.00 

Total Petroleum Production And Marketing 0.01 0.01 0.01 0.01 

TOTAL STATIONARY SOURCES 0.40 0.41 0.41 0.42 

 

MOBILE SOURCES 

Other Mobile Sources 

810-Aircraft 0.04 0.06 0.06 0.07 

830-Ships And Commercial Boats 12.92 15.74 17.36 17.97 

Total Other Mobile Sources 12.96 15.80 17.43 18.04 

TOTAL MOBILE SOURCES 12.96 15.80 17.43 18.04 

 

TOTAL OCS AIR BASIN 13.36 16.20 17.84 18.45 

TOTAL VENTURA COUNTY 75.19 64.25 59.49 58.20 

NOTES:

Source: CEFS v1.06 (November 2006). 

External ARB adjustments to CEFS v1.06 are noted in Table 4-3. 

Table 3-7 State proposed 2012 reductions are not included. 

Data rounding may affect displayed values and totals. 
Appendix D 

Attainment Demonstration 

FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE D-1 

PREFACE 

This appendix includes two sections - both prepared by the California Air Resources 

Board for the Ventura County Air Pollution Control District: Protocol for Photochemical 

Modeling of Ozone in Ventura County and Ventura County Weight of Evidence 

Assessment. Page numbers are sequential in the appendix, and there is a table of 

contents for each of the sections at the beginning of the appendix. 
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PAGE D-2 MAY 2008 

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TABLE OF CONTENTS 

SECTION I: PROTOCOL FOR PHOTCHEMICAL MODELING OF OZONE IN 

VENTURA COUNTY

1. INTRODUCTION............................................................................................ D-15 

2. AIR QUALITY MODELING DOMAIN AND MODELING TOOLS................... D-17 

2.1. Modeling Domain Description and Modeling Tools.............................. D-17 

2.1.1. Modeling Domain ...................................................................... D-17 

2.1.2. Air Quality Model....................................................................... D-19 

2.1.3. Meteorological Modeling ........................................................... D-19 

3. OZONE EPISODE SELECTION .................................................................... D-21 

4. AIR QUALITY MODEL INPUT PREPARATION............................................ D-23 

4.1. Meteorology Inputs .............................................................................. D-23 

4.1.1. Meteorological Fields Evaluation............................................... D-24 

4.2. Initial and Boundary Concentrations for Air Quality Modeling.............. D-33 

4.3. Emissions Inventory Development....................................................... D-37 

4.3.1. Emissions Quality Assurance.................................................... D-38 

5. BASE YEAR SIMULATION RESULTS.......................................................... D-47 

5.1. Base Year Results and Air Quality Model Performance Evaluation..... D-47 

5.1.1. Statistical Base-Case Evaluation .............................................. D-47 

5.1.2. Sensitivity Analyses .................................................................. D-53 

5.1.2.1. Boundary Condition Sensitivity ................................. D-53 

5.1.2.2. Meteorological Field Sensitivity................................. D-54 

5.1.2.3. Emissions Inventory Sensitivity................................. D-56 

6. PREDICTION OF FUTURE-YEAR DESIGN VALUES................................... D-59 

6.1. Methodology ........................................................................................ D-59 

6.2. 8-Hour Ozone Design Values .............................................................. D-59 

6.3. Model Performance and Ozone Threshold Criteria.............................. D-60 

6.4. Calculation of Site Specific RRFs and Future-Year Design Values ..... D-60 

6.5. Sensitivities of Relative Reduction Factors to Meteorological Inputs ... D-62 

6.6. Sensitivity of Projected Future-Year Design Values to Emissions ....... D-63 

7. REFERENCES............................................................................................... D-65 
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LIST OF FIGURES 

Figure 2-1 The Southern California Ozone Study (SCOS) air quality modeling 

domain showing terrain contours ......................................................... D-18 

Figure 3-1 Locations of surface meteorology monitoring sites in the vicinity of 

Ventura County.................................................................................... D-21 

Figure 4-1 The Southern California Ozone Study (SCOS) modeling domain 

and model-performance subregions .................................................... D-25 

Figure 4-2 Locations of surface meteorology monitoring sites in the vicinity of 

Ventura County.................................................................................... D-25 

Figure 4-3 Comparisons of measured and observed hourly winds for Ventura 

County during the August 3-9, 2005 (DOY 215-221) period ................ D-26 

Figure 4-4 Measured (red) and simulated (blue) surface wind vectors for 

August 05, 2005 at 0300 PDT.............................................................. D-28 

Figure 4-5 Measured (red) and simulated (blue) surface wind vectors for 

August 05, 2005 at 1500 PDT.............................................................. D-29 

Figure 4-6 Simulated (blue) wind vectors at 500 magl for August 04, 2005 at 

0100 PDT............................................................................................. D-30 

Figure 4-7 Comparison of hourly measured and simulated air temperatures in 

Ventura County during the August 3-9, 2005 (DOY 215-221) 

episode ................................................................................................ D-31 

Figure 4-8 Simulated hourly mixing heights at Ojai ('a'), Simi Valley ('b'), and 

Emma Wood State Beach ('c') during the August 3-9, 2005 (DOY 

215-221) episode period...................................................................... D-32 

Figure 4-9 Vertical ozone concentration (ppb) profiles (blue lines) measured 

August 5, 1997 at 0200 PDT at CSU Northridge (a), Pomona (b), 

Valley Center (c), Anaheim (d), USC(e), and UC Riverside (f) ............ D-36 

Figure 4-10 The spatial distribution of area-source NOx (g-mole/hour) 

emissions during a typical weekday at 1500 PDT, during the 

summer of 2005................................................................................... D-41 

Figure 4-11 The spatial distribution of on-road, mobile-source NOx (gmole/hour) emissions during a typical weekday at 1500 PDT, during 

the summer of 2005............................................................................. D-42 

Figure 4-12 The spatial distribution of surface-level, point source NOx (gmole/hour) emissions during a typical weekday at 1500 PDT, during 

the summer of 2005............................................................................. D-43 
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LIST OF FIGURES (cont’d) 

Figure 4-13 The spatial distribution of elevated, point-source NOx (g-mole/hour) 

emissions during a typical weekday at 1500 PDT, during the 

summer of 2005................................................................................... D-44 

Figure 4-14 The spatial distribution of biogenic ROG (g-mole/hour) emissions 

during a typical weekday at 1500 PDT, during the summer of 2005.... D-45 

Figure 5-1 Ozone monitoring sites in Ventura County during years 2004 and 

2005..................................................................................................... D-48 

Figure 5-2 Measured (numbers) and simulated (contours) ozone 

concentrations on August 6, 2005 (DOY 218) at 1500 PDT ................ D-50 

Figure 5-3 Comparison of measured (points) and simulated (lines) hourly 

ozone concentrations (ppb) from the August 3-9 episode base case 

simulation (mA01)................................................................................ D-51 

Figure 5-4 Simulated and observed daily 1-hour ozone concentrations for 

Ventura County from the August 3-7, 2005 episode ............................ D-52 

Figure 6-1 Year 2012 8-hour ozone design values (ppb) in response to 

anthropogenic ROG and NOx emissions reduction for Simi Valley 

(A) and for Ojai (B)............................................................................... D-64 
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LIST OF TABLES 

Table 2-1 Coordinate definitions for the 1997 Southern California Ozone 

Study (SCOS) modeling domain.......................................................... D-18 

Table 3-1 Ozone episodes selected by the SCAQMD for analysis and high 

8-hour ozone concentrations (ppb) in Ventura County ........................ D-22 

Table 4-1 Vertical layer assignments for the CAMx air quality model and the 

MM5 meteorological model.................................................................. D-24 

Table 4-2 Clean air concentrations of Reactive Organic Gases (ROG) used 

for initial and boundary concentrations for modeling ozone in the 

Southern California Ozone Study (SCOS) domain .............................. D-34 

Table 4-3 Reactive Organic Gases (ROG) samples (units are ppbC) collected 

using aircraft on August 4 and 5, during the 1997 Southern 

California Ozone Study........................................................................ D-35 

Table 4-4 Emissions inventory domain-wide totals (ton/day) for a weekday 

and a weekend day 2005..................................................................... D-39 

Table 4-5 Daily emissions totals (ton/day) for Ventura County for selected 

days during the August 3-9, 2005 episode period for the year 2005 

and the year 2012 baseline.................................................................. D-40 

Table 5-1 Ozone model performance statistical measures for five 2004 and 

2005 episode, for Ventura County (SR0002)....................................... D-49 

Table 5-2 Model performance statistical measures for 1-hour ozone 

concentrations, for selected sensitivity analyses based on 

alterations of the air temperature, wind, and mixing height fields 

during the August 3-9, 2005 episode ................................................... D-55 

Table 5-3 Ozone model performance statistical measures for selected 

sensitivity analyses based on alterations of the August 3-9, 2005 

base case emissions inventory ............................................................ D-56 

Table 6-1 Weighted-averaged, eight-hour ozone design values (ppb) for the 

year 2002 for those sites in violation of the 8-hour NAAQS for 

ozone................................................................................................... D-61 

Table 6-2 Observed and simulated daily 8-hour ozone concentrations at 

selected Ventura County monitoring sites (ppb). ................................. D-61 

Table 6-3 Estimated year 2012 ozone design values for Ojai and Simi Valley 

using controlled emissions as function of adjustments to the air 

temperature and mixing height inputs to the air quality model............. D-63 
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SECTION II: VENTURA COUNTY WEIGHT OF EVIDENCE ASSESSMENT 

1. INTRODUCTION............................................................................................ D-69 

2. U.S. EPA ATTAINMENT DEMONSTRATION REQUIREMENTS.................. D-69 

3. HISTORICAL CONTEXT ............................................................................... D-70 

4. ASSESSMENT OF RECENT AIR QUALITY TRENDS.................................. D-72 

4.1. General Basinwide Perspective ........................................................... D-72 

4.2. Regional Analysis ................................................................................ D-74 

5. ADDITIONAL SUPPORTING ANALYSES .................................................... D-75 

5.1. Rollback Analysis................................................................................. D-75 

5.2. Additional Air Quality Analyses ............................................................ D-76 

 5.2.1. Mean of the Top 30 8-Hour Ozone Concentrations................... D-76 

 5.2.2. Design Value Regression Analyses .......................................... D-78 

6. EMISSIONS AND PRECURSOR TRENDS ................................................... D-80 

6.1. Emissions Trends ................................................................................ D-80 

6.2. Precursor Trends ................................................................................. D-80 

7. PHOTOCHEMICAL MODELING RESULTS.................................................. D-81 

8. SUMMARY..................................................................................................... D-82 
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LIST OF FIGURES 

Figure 1 Ventura County Land Area .................................................................. D-71 

Figure 2 Ventura County Ozone Statistics 1988 to 2006 ................................... D-72 

Figure 3 Ventura County Change in Federal 8-Hour Exceedance Days - 

1995 to 2005 ....................................................................................... D-74 

Figure 4 Ventura County Change in Number of Federal 8-Hour Exceedance 

Days by Region 1995 and 2006 .......................................................... D-75 

Figure 5 Mean of Top 30 8-Hour Ozone Concentrations at Simi Valley and 

Ojai ...................................................................................................... D-77 

Figure 6 Mean of Top 30 8-Hour Ozone Concentrations at Simi Valley and 

Ojai Normalized to the 1988-1990 3-Year Average ............................ D-78 

Figure 7 Simi Valley Federal 8-Hour Ozone Design Value and Linear 

Regression Line................................................................................... D-79 

Figure 8 Ojai Federal 8-Hour Ozone Design Value and Linear Regression 

Line...................................................................................................... D-79 

Figure 9 Ventura County Estimated ROG and NOx Emissions 1995 to 2006.... D-80 

Figure 10 Simi Valley and El Rio Summer Morning Average ROG and NOx 

from PAMS Network Stations .............................................................. D-81 
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PROTOCOL FOR PHOTCHEMICAL MODELING OF OZONE 

IN VENTURA COUNTY

2/1/2008 

Prepared for 

Ventura County Air Pollution Control District 

Ventura, California 93003 

Prepared by 

California Environmental Protection Agency 

California Air Resources Board 

Planning and Technical Support Division 

Sacramento, California 95814
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1. INTRODUCTION 

This document was prepared by the California Air Resources Board (CARB) to assist 

the Ventura County Air Pollution Control District in the development of a year 2008 

ozone attainment plan for Ventura County. This document is a protocol that describes 

the use of an ozone air quality model to estimate future-year 8-hour ozone design 

values. The need for and purpose of the protocol document have been described in a 

technical guidance document adopted by the CARB (1992). 

The primary purpose of this protocol is to describe the procedures used to model ozone 

concentrations in Ventura County and the use of the results to project concentrations in 

future years. The objective is to promote the review of these procedures and 

encourage participation in the development of strategies to meet federal and state air 

quality standards for ozone. 
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2. AIR QUALITY MODELING DOMAIN AND MODELING TOOLS

Air quality in Ventura County is often strongly influenced by air quality in the South 

Coast Air Basin (SCAB). Los Angeles County is adjacent to Ventura, and dwarfs 

Ventura County in terms of population and anthropogenic emissions. Therefore, any 

model-based analysis of ozone air quality in Ventura County must include Los Angeles 

County, if not the whole SCAB. 

To avoid replicating work, much of the ozone modeling for Ventura County was taken 

from work done by the South Coast Air Quality Management District (SCAQMD) in 

preparation for their contribution to the 2007 California ozone State Implementation Plan 

(SIP). The SCAQMD prepared modeling analysis for six high-ozone episodes that 

occurred during 2004 and 2005 (SCAQMD, 2007). These analyses were based on the 

1997 South Coast Ozone Study (SCOS) domain which includes Ventura County (Figure 

2-1). 

2.1. Modeling Domain Description And Modeling Tools 

2.1.1. Modeling Domain

The 1997 SCOS air quality modeling domain was defined in a Lambert Conical 

Projection with 2 parallels (see Table 2-1). The Lambert Project was selected based on 

the needs of the prognostic meteorological modeling used to generate the 

meteorological inputs required by the air quality model. The horizontal grid consisted of 

116x80 grid cells with a resolution of 5x5 km. The domain covers 232,000 km2; over 

89,000 square miles. 

Figure 2-1 shows the boundaries of the ozone modeling domain. The northern 

boundary of the model extends into Santa Barbara and Kern counties, while the 

southern boundary extends into Mexico. The eastern boundary of the modeling domain 

is over 230 miles east of Ventura County in the desert portions of San Bernardino and 

Riverside counties, while the western boundary extends 155 km (96 miles) beyond the 

westernmost point of the County’s shoreline. 
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Table 2-1 Coordinate definitions for the 1997 Southern California Ozone Study (SCOS) 

modeling domain. 

 Lambert Conical Projection with 2 Parallels

 Parallels: 30N and 60N 

 Central Meridian: 118.0 W 

 Origin (0x0 km): N x 118W 

 Air Quality Modeling Domain

 Lower, Left Hand Corner: -290 x 225 km 

 Number of Cells: 116 x 80 

Figure 2-1 The Southern California Ozone Study (SCOS) air quality modeling domain 

showing terrain contours. 

500

500

500

500

500

500

500 500

500

500

1000

1000

1000 1000

1000

1000

1000

1000

1000

1000

1000

Ventura 

Santa

Barbara 

Los Angeles 

Orange

San Diego Imperial 

Riverside 

Kern 

San Bernardino 

San Luis 

Obispo 
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2.1.2. Air Quality Model

The U.S. EPA (2005) modeling guidelines did not recommend any single air quality 

model for the development of a SIP. Instead, the U.S. EPA recommended a number of 

criteria for selecting an air quality model. Among these criteria were: 

 the model should be peer reviewed by the science community 

 the model should be appropriate for the specific application 

 the model should be used with a data base that is appropriate for the application 

 the model should have a proven track record of successful use 

 the model should be used in a manner consistent with a protocol describing its use 

The U.S. EPA (2005) listed a number of air quality models that met the above criteria 

and among them was CAMx (ENVIRON, 2004). Because the CAMx model has an 

additional advantage over other models in that it is being used by the California Air 

Resources Board (CARB) in other parts of California (CARB, 2007), there is a base of 

local knowledge concerning its application and use. 

For the Ventura County SIP, the CAMx v4.4-beta with SAPRC99 chemistry was 

selected. The v4.4-beta is an upgrade to the most recently available version of CAMx 

v4.3. In CAMx v4.3 there is no explicit representation for three chemical species that 

are important to understanding ozone chemistry in California; these are methyl butenol 

(MBUT), ethanol (ETOH), and methyl tert-butyl ether (MTBE). The MBUT is a 

component of biogenic emissions associated with conifers and is found in most of the 

mountainous areas of California. The species ETOH and MTBE are important 

components of automobile gasoline in California. ENVIRON incorporated explicit 

representations of these species into v4.4beta at the request of the SCAQMD (2006). 

2.1.3. Meteorological Modeling

The U.S. EPA’s 2005 modeling guidance encourages the use of a prognostic 

meteorological model to generate the meteorological fields needed in an air quality 

model. The MM5 prognostic meteorological model (Grell et. al., 1993) is well known 

and widely used in the United States for generating regional meteorological fields. The 

MM5 model is a non-hydrostatic model with a pressure-normalized (sigma) terrainfollowing coordinate system. The model uses global-scale simulation results to define 

initial and boundary concentrations, and multiple nesting layers to generate gridded 

meteorological fields at smaller scales that are more appropriate for air quality 

modeling. 
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3. OZONE EPISODE SELECTION

Five of the six ozone episodes selected for analysis by the SCAQMD were selected 

primarily for the high ozone concentrations observed in the SCAB. The sixth episode 

(August 3-9, 2005) was selected for high ozone concentrations within Ventura County. 

Each of the episodes recorded 8-hour ozone concentrations of 85 ppb or greater within 

Ventura County. However, for most of the episodes, ozone concentrations of 60 ppb or 

greater did not occur at more than one site very often. With only a few monitoring sites 

to base analyses on, there were greater uncertainties in air quality model performance. 

The episodes modeled are listed in Table 3-1 with 8-hour ozone concentrations 

measured in Ventura County. 

Figure 3-1 shows the air monitoring sites operating in Ventura County during years 

2004 and 2005. They are: Ojai (3172), Emma Wood State Beach (2756), Rio Mesa 

(2991), Piru (2702), Simi Valley (2880), and Thousand Oaks (2984). 

Figure 3-1: Locations of surface meteorology monitoring sites in the vicinity of Ventura 

County 
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Table 3-1: Ozone episodes selected by the SCAQMD for analysis and high 8-hour 

ozone concentrations (ppb) in Ventura County. 

 Simi Piru Thousand Ojai Emma 

 Episode Day Valley Oaks Woods 

----------------------------------------------------------- 

 June, 2004 03 nd nd nd nd nd 

 04 085 082 068 086 055 

 05 095 080 069 078 052 

 06 082 075 071 074 065 

 07 061 060 058 059 055 

 August, 2004 04 060 063 049 066 051 

 05 077 053 074 076 059 

 06 083 080 073 086 041 

 07 073 076 064 079 037 

 08 074 079 051 075 035 

 May, 2005 17 056 053 052 053 044 

 18 062 064 059 060 037 

 19 072 073 061 067 028 

 20 047 047 040 053 035 

 21 082 070 068 064 047 

 22 084 msg 077 072 050 

 23 076 071 066 067 057 

 24 076 069 068 066 061 

 July, 2005 14 063 049 044 070 033 

 15 085 080 061 089 046 

 16 082 069 060 083 046 

 17 085 068 056 079 039 

 18 073 068 046 076 035 

 19 085 083 061 082 032 

 August, 2005 03 085 083 066 081 069 

 04 081 081 065 083 049 

 05 094 086 064 084 042 

 06 093 082 066 085 039 

 07 075 068 054 069 044 

 08 080 070 057 064 047 

 09 069 072 056 069 051 

 August, 2005 25 075 071 074 057 060 

 26 053 064 059 047 048 

 27 065 066 057 068 043 

 28 086 080 068 071 042 

 29 085 082 062 085 034 

-----------------------------------------------------------
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4. AIR QUALITY MODEL INPUT PREPARATION

4.1. Meteorology Inputs

The meteorology inputs required by the CAMx air quality model were generated using 

the MM5 prognostic meteorological model. The MM5 modeling domain was centered at 

34.537N x 118 W and included nested domains of 45-, 15-, and 05 km. The 5-km 

domain consisted of 120x84 grid cells. The vertical MM5 domain consisted of 34 layers 

to a height of approximately 15,000 magl. There was a 500-km northing offset between 

the meteorological modeling domain and the air quality modeling domain. 

For each of episode modeled, the MM5 model was initialized on the day prior to the 

beginning of each simulation period. For example, for the July, 2005 episode, the 

simulation was initialized at July 12, 1200 GMT – 0500 PDT. Analysis nudging was 

used for the 45- and 15-km grids at 6-hour intervals. Because of the limited amount of 

upper-air data available, no observational nudging was done for layers above the 

surface. 

Within the 5-km grid, the MRF scheme was used to describe the planetary boundary 

layer. The multi–layer soil model was used to describe the surface energy budget (see 

Grell, et. al., 1993). Surface wind measurements were used for nudging (observational 

FDDA) for all of the episodes, except for the August 3-9, 2005 episode. Further details 

were described in SCAQMD (2007). 

The MM5 output was post-processed for CAMx input using software provided by 

ENVIRON (2004). The 34 layers from the meteorological modeling domain were 

mapped into 16 layers to a height of approximately 5,000 magl for the air quality 

modeling domain. Table 4-1 shows the nominal height and thickness of each layer. 

Vertical diffusivities were estimated using O'Brien (1970). To limit potential numerical 

artifacts in the meteorological parameter fields on the nest boundaries, 2 grid cells were 

removed from the 5-km MM5 output, resulting in a grid of 116x80 grid cells and is the 

bases of the air quality modeling domain. 

 
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Table 4-1: Vertical layer assignments for the CAMx air quality model and the MM5 

meteorological model. 

 CAMx MM5 Height Thickness 

 No. No. magl m 

 

 1 1 36. 36. 

 2 3 109. 73. 

 3 5 220. 111. 

 4 7 369. 149. 

 5 9 521. 152. 

 6 11 675. 154. 

 7 13 911. 236. 

 8 15 1235. 324. 

 9 17 1569. 334. 

 10 19 2095. 526. 

 11 20 2462. 367. 

 12 21 2942. 480. 

 13 22 3449. 507. 

 14 23 3984. 535. 

 15 24 4553. 569. 

 16 25 5160. 607. 

 

4.1.1. Meteorological Fields Evaluation

The U.S. EPA (2005) recommends an evaluation of meteorological inputs for air quality 

modeling but does not specify acceptability criteria or standards. In this section, the 

wind, temperature, and mixing-height fields are compared with available measurements. 

The SCOS modeling domain contains diverse terrain and surface types. Contrasts 

between the ocean surface and land, coastal plains and inland high-deserts, east-west 

running and north-south running mountains result in complex wind and air temperature 

patterns. Averaging wind or temperatures over the domain can hide discrepancies 

between measured and simulated features. Therefore, the meteorological model 

performance was evaluated by subregions of the modeling domain shown in Figure 4-1. 

Air quality and meteorological features are generally not confined by political 

boundaries. However, the political boundary between Los Angeles and Ventura 

Counties is also a region of convergent air flow. Therefore, it was appropriate to 

represent Ventura County as a subregion separate from Los Angeles County. 
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Figure 4-1: The Southern California Ozone Study (SCOS) modeling domain and 

model-performance subregions. 

Figure 4-2 Locations of surface meteorology monitoring sites in the vicinity of Ventura 

County 

Zone 0

Zone 2

Zone 1

Zone 3

Zone 4

Zone 5

Zone 6

Zone 7

Zone 8

Zone 9

500

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1000

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1000 1000

1000
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Twelve meteorological monitoring sites were identified within Ventura County are shown 

in Figure 4-2. The hourly wind speeds averaged for all sites and hourly root mean 

square differences (RMSE) between measured and simulated wind speed components 

(i.e., east-west component and north-south component) were calculated and are 

summarized in Figure 4-3. In this section, results from the August 3-9, 2005 episode 

period are presented as typical of results from all six of the episodes. In Figure 4-3, the 

upper graph compares the average measured (solid line) and simulated (dashed line) 

wind speed. The lower graph compares the root mean square difference in 

'u' component (solid line) and 'v' component (dashed line) wind speed. 

Figure 4-3 Comparisons of measured and observed hourly winds for Ventura County 

during the August 3-9, 2005 (DOY 215-221) period. The upper graph compares the 

average measured (solid line) and simulated (dashed line) wind speed. The lower 

graph compares the root mean square difference in 'u' component (solid line) and 

'v' component (dashed line) wind speed. 

The simulated averaged afternoon wind speeds showed general agreement with 

measured wind speeds. However, simulated overnight wind speeds were greater than 

those observed. The discrepancy between daytime and nighttime performance can be 

partly explained by the complex topography of Ventura County: in general, the northern 

half of Ventura County is at higher elevations than the southern half. The MM5 model 

tended to over-emphasize the nighttime katabatic flow (see Figure 4-4). During 

215 216 217 218 219 220 221 222

8

7

6

5

4

3

2

1

0

Mean Wind Speed (mps)

215 216 217 218 219 220 221 222

5

4

3

2

1

0

Day of Year 2005

RMSE Wind Speed (mps)

215 216 217 218 219 220 221 222

5

4

3

2

1

0

Day of Year 2005

RMSE Wind Speed (mps)

Hourly Mean and RMS Surface-Level Wind Speed Components (mps) -- m01/z02
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afternoons, the stronger sea-breeze was reflected throughout most of the County in 

both the measurements and the simulated results (see Figure 4-5). These 

discrepancies are also reflected in the component winds (Figure 4-3). During the 

nighttime hours, there was a greater RMSE in the north-south component wind than in 

the east-west component. During the daytime hours, there was a smaller RMSE in the 

north-south component. 

Easterly wind flow aloft was in important feature of the simulated wind fields of the 

August 3-9, 2005 episode. In this feature, the August 3-9, 2005 episode was unique. 

Such easterly winds are frequently measured by the radar wind profiler (RWP) at Simi 

Valley. Unfortunately, during the August 3-9, episode there were few data available 

from this RWP. Figure 4-6 illustrates the simulated wind field at 500 meters above 

ground level (magl) on August 4 at 0100 PDT. Easterly wind flow throughout Ventura 

County is evident. The lone measurement from the radar wind profiler (RWP) at Simi 

Valley supports the simulated flow pattern. 

The hourly measured and simulated air temperatures were averaged and root mean 

square errors (RMSE) air temperatures were calculated and summarized in Figure 4-7. 

The MM5 model tended to overestimate temperatures throughout the episode. The 

RMSE air temperatures were as high as 7 ̊C. Because sensitivity analyses have shown 

that ozone chemistry was assumed to be relatively insensitive to air temperatures (see 

Chapter 5), these discrepancies were not expected to have a large impact on simulated 

ozone concentrations. However, the relatively large temperature RMSE may explain 

some of the discrepancies in simulated wind speed due to the relationships between air 

temperatures, air densities, the forcing for meso-scale winds. 

There were no regular measurements in Ventura County from which mixing heights 

could be estimated. Figure 4-7 shows simulated mixing heights at Ojai, Simi Valley, 

and Emma Wood State Beach during the August 3-9, 2005 episode period. Maximum 

daily mixing heights were expected to be lower along the coast and then increase inland 

with distance from the coast. This pattern is observed in Figure 4-7. However, the 

simulated maximum mixing heights were much higher than expected for Ventura 

County by at least a factor of 2 (e.g., Hanna et. al, 1989). Of the 3 sites, the highest 

mixing heights, in excess of 2000 magl, were simulated at Simi Valley. A further 

analysis of the mixing heights is provided in Chapter 5. 
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Figure 4-4 Measured (red) and simulated (blue) surface wind vectors for August 05, 

2005 at 0300 PDT. The vector lengths represent 1-hour wind run. 

500

500

500

500

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1000

1000

1000

1000

1000

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1000

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1000
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Figure 4-5: Measured (red) and simulated (blue) surface wind vectors for August 05, 

2005 at 1500 PDT. The vector lengths represent 1-hour wind run. 

500

500

500

500

500

1000

1000

1000

1000

1000

1000

1000

1000

1000
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PAGE D-30 MAY 2008 

Figure 4-6: Simulated (blue) wind vectors at 500 magl for August 04, 2005 at 0100 

PDT. The vector lengths represent 1-hour wind run. Note the single wind 

measurement (red) at Simi Valley. 

500

500

500

500

500

1000

1000

1000

1000

1000

1000

1000

1000

1000
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MAY 2008 PAGE D-31 

Figure 4-7: Comparison of hourly measured and simulated air temperatures in Ventura 

County during the August 3-9, 2005 (DOY 215-221) episode. The upper graph 

compares the average measured (solid line) and simulated (dashed line) air 

temperatures. The lower graph shows the root mean square difference in measured 

and simulated air temperatures. 

215 216 217 218 219 220 221 222

40

30

20

10

p ()

215 216 217 218 219 220 221 222

10

8

6

4

2

0

Day of Year 2005 -- Zone 02

p ()
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PAGE D-32 MAY 2008 

Figure 4-8: Simulated hourly mixing heights at Ojai ('a'), Simi Valley ('b'), and Emma 

Wood State Beach ('c') during the August 3-9, 2005 (DOY 215-221) episode period. 

215 216 217 218 219 220 221 222

2000

1600

1200

800

400

0

215 216 217 218 219 220 221 222

2000

1600

1200

800

400

0

215 216 217 218 219 220 221 222

2000

1600

1200

800

400

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Hourly PBL Heights (magl) -- m01/z02

a) Ojai

b) Simi Valley

c) Emma Wood
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4.2. Initial and Boundary Concentrations for Air Quality Modeling

The SCOS modeling domain is bounded on the west by the Pacific Ocean which is 

characteristically the source of most of the air flowing into Ventura County and the 

SCAB (e.g., CARB, 1984 – see Figure 2-1). Since the Pacific Ocean is generally free of 

anthropogenic emissions, the assumption that it is "clean air" is reasonable. The U.S. 

EPA (1991) defined a clean air profile for photochemical modeling purposes. This 

profile (see Table 4-2) included 40 parts per billion (ppb) of ozone, 2 ppb of nitrogen 

oxides (NOx), and approximately 22 ppbC of reactive organic gasses (ROG). 

At monitoring sites along the California coastline, ozone concentrations of between 30 

and 40 ppb have often been measured (data not shown). However, there is uncertainty 

whether ozone concentrations of less than 40 ppb represent background because of the 

proximity of NOx emissions sources along the coastline. For lack of better information, 

a background ozone concentration of 40 ppb was assumed at the surface. 

Newchurch et. al. (2003) reported that long-term measurements of ozone aloft in 

northern California were higher than 40 ppb. During the August, episode of the 1997 

SCOS field study, ozone concentrations at 5000 magl averaged 60 ppb (see Figure 4-

9). Therefore, for this analysis, the top ozone concentration at the top of the domain 

boundary (approximately 5,000 magl) was set to 60 ppb. 

The U.S. EPA (1991) recommends a clean air NOx concentration of 2 ppb. As part of 

the episodic modeling done for the South Coast Air Basin (SCAB), sensitivity analyses 

using the air quality model showed that in the absence of anthropogenic emissions, 

simulated ozone concentrations were as high as 65 ppb – far higher than the assumed 

background concentration of 40 ppb. Since biogenic emissions are an unavoidable 

source of ROG, the NOx concentrations from the boundaries were the cause of the 

ozone. 

Other sensitivity analysis have shown that the half-life for the conversion of NOx to 

nitrate (NO3) over the Pacific Ocean was approximately 10% per hour. From these 

results it seemed reasonable, given the length of the trajectories over the Ocean, that 

little NOx should remain by the time the air flow reached the coast of California. 

Allowing for the possibility of some offshore shipping (the international shipping lanes 

offshore from southern California are within the boundaries of the modeling domain), on 

the offshore boundaries the NOx concentration was assumed to be 2 ppb to a height of 

200 magl. Above 200 m, boundary NOx concentrations were set to 0.1 ppb. Onshore, 

the vertical boundary NOx concentration was set to 2 ppb. Sensitivity analysis using 

this modified boundary concentration in the absence of anthropogenic emission results 

in peak simulated ozone concentrations of between 35 and 45 ppb (see Chapter 5). 
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Table 4-2: Clean air concentrations of Reactive Organic Gases (ROG) used for initial 

and boundary concentrations for modeling ozone in the Southern California Ozone 

Study (SCOS) domain. The ROG species were based on the U.S. EPA (1991) 

concentrations defined using the Carbon Bond IV mechanism and translated to the 

SAPRC99 chemical mechanism. 

 Carbon Bond IV SAPRC99 

 Carbon Conc. Carbon1/ Conc. 

 Species Number ppbC Species Number ppbC 

 OLE 2. 0.6 OLE1 3.9 0.7 

 PAR 1. 14.9 OLE2 4.4 0.0 

 TOL 7. 1.3 ALK1 2.2 5.5 

 XYL 8. 0.8 ALK2 2.4 5.5 

 FORM 1. 2.1 ALK3 4.4 4.1 

 ALD2 2. 1.1 ALK4 5.5 0.0 

 ETH 2. 1.0 ALK5 8.3 0.0 

 ISOP 5. 0.1 HCHO 2.0 1.9 

 MEOH 1. 0.1 CCHO 3.1 1.7 

 ETOH 1. 0.1 RCHO 4.1 1.0 

 ---- ARO1 6.8 1.4 

 Total (ppbC) 22.0 ARO2 8.2 0.6 

 ETHE 2.0 0.7 

 ISOP 5.0 0.1 

 MEOH 1.0 0.1 

 ETOH 2.0 0.0 

 ---- 

 Total (ppbC) 24.3 

1/ The Carbon Number was estimated by dividing the molecular weight by 14. 

 g-mole/C. 
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MAY 2008 PAGE D-35 

Table 4-3: Reactive Organic Gases (ROG) samples (units are ppbC) collected using 

aircraft on August 4 and 5, during the 1997 Southern California Ozone Study. The 

approximate site locations are Santa Catalina Island (S.Cat), San Nicholas Island 

(S.Nic), Point Conception (Pt.Con), El Monte (E.Mon), Riverside (River), Banning 

(Bann), Van Nuys (V.Nuys), Fallbrook (Rmond). 

 U.S. EPA 

 Clean S.Cat S.Cat S.Nic S.Nic Pt.Con 

 Height (ft) 300 100 150 4500 4500 

 Time (PDT) 09 14 08 08 09 

 Category ----- ----- ----- ----- ----- ----- 

 OLE 0.6 1.3 0.7 0.6 0.5 0.7 

 PAR 14.9 146.2 29.3 12.7 7.7 14.4 

 TOL 1.3 32.0 7.9 3.3 2.4 4.0 

 XYL 0.8 9.8 1.8 2.3 1.4 1.8 

 FORM 2.1 8.8 nd 2.7 4.0 2.4 

 ALD2 1.1 1.2 nd 1.2 1.0 0.8 

 ETH 1.0 0.0 0.0 0.0 0.0 0.0 

 ISOP 0.1 0.0 0.0 0.0 0.0 0.0 

 ----- ----- ----- ----- ----- ----- 

 Totals 21.9 199.3 39.7 22.8 17.0 24.1 

 E.Mon River Bann Hesp VNuys Rmond 

 Height (ft) nd nd nd nd nd nd 

 Time (PDT) 15 08 07 06 05 05 

Category ----- ----- ----- ----- ----- ----- 

 OLE 0.1 0.0 0.0 0.0 0.2 0.0 

 PAR 30.8 120.7 22.3 22.5 46.2 26.0 

 TOL 2.0 3.0 0.7 1.0 4.8 1.4 

 XYL 1.3 0.8 0.0 0.2 3.0 0.4 

 FORM nd1/ nd nd nd nd nd 

 ALD2 nd nd nd nd nd nd 

 ETH 0.0 0.0 0.0 0.0 0.0 0.0 

 ISOP 0.0 0.0 0.0 0.0 0.0 0.0 

 ----- ----- ----- ----- ----- ----- 

 Totals 34.9 124.5 23.3 24.1 55.9 28.1 

1/ 'nd' – no data 
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Figure 4-9: Vertical ozone concentration (ppb) profiles (blue lines) measured August 5, 

1997 at 0200 PDT at CSU Northridge (a), Pomona (b), Valley Center (c), Anaheim (d), 

USC(e), and UC Riverside (f). The vertical temperature profiles (red lines) are also 

shown, but without scale. Height (m)

ANAH DOY:217 Hr02 PDT

0

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5000

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20406080

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VCEN DOY:217 Hr02 PDT

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20406080

100120140160

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100120140160

a) b) c)

d) e) f)
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MAY 2008 PAGE D-37 

During the 1997 SCOS field study ROG concentrations of between 15 and 235 ppbC 

were measured throughout the SCAB (Table 4-3). These concentrations are consistent 

with the clean air definition of U.S. EPA (1991). These modeling analyses, the 

concentrations were converted from the Carbon Bond IV profiles to the SAPRC99 

profiles taking care to match the concentrations by category (see Table 4-2). 

The initial ozone concentrations were identical to the boundary concentrations up to 

1000 magl (vertical layers 1-9). Above 1000 magl, the ozone initial ozone concentration 

was set to 60 ppb to maintain initial consistency with the top boundary concentration. 

4.3. Emissions Inventory Development

Emissions inventories for at least 3 years were required for each of the six episodes 

modeled: the base year (2004 or 2005), the year 2002, and the future year. Area- and 

point-source emissions totals by county were provided by the California Emissions 

Forecast System (CEFS) using a base year of 2002 and extrapolating to 2004, 2005, 

2012 and 2017 (Inventory Reference No. 980). Monthly adjusted weekday and 

weekend day emissions totals were provided. The emissions were spatially 

disaggregated using gridded surrogates based on STI (2001). 

The on-road, mobile source emissions totals were derived by county using EMFAC 

v2.24.6 (the latest version of the Emission FACtors model used to calculate emission 

rates from on-road motor vehicles). The spatial and temporal distribution of on-road, 

mobile-source emissions was calculated using DTIM4 (the latest version of the Direct 

Travel Impact Model used to produced gridded on-road motor vehicle emissions) and 

using estimates of Vehicle Miles Traveled (VMT) provided by the South California 

Association of Governments (SCAG, 2006). 

For DTIM, hourly, gridded temperature fields were calculated from measurements. The 

temperature measurements were adjusted for height above ground level prior to 

interpolation. These gridded temperature fields were also used to calculate the countyspecific, hourly average temperatures weighted by VMT, needed to run EMFAC. The 

gridded hourly emissions fields from DTIM were scaled by county to match the 

emissions estimates from EMFAC. Spatial and temporal adjustments to the gridded 

emissions were made for weekend days. 

Day-specific biogenic emissions were calculated using the California Air Resources 

Board (CARB) model BEGIS (Scott and Benjamin, 2003). The hourly, gridded 

temperature fields used to run DTIM were also used to run BEGIS. The BEGIS model 

generates gridded hourly emissions for isoprene, monoterpenes, and methyl-tributenol. 

An additional 30% of the mass was assigned to 'other volatile organic components' 

(OVOC), to represent unmeasured chemical species. 

Two sets of emissions inventories were prepared for modeling ozone concentrations for 

the year 2012. The 2012 baseline inventory was derived from the CARB's California 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE D-38 MAY 2008 

Emissions Forecasting System (CEFS), adjusted for reductions from adopted rules and 

other corrections not reflected in the CEFS version 1.06 inventory that was frozen for 

SCAQMD modeling purposes. The 2012 controlled emissions inventory scenario 

reflects reductions from the 2007 California State Strategy for the SIP approved by the 

CARB. 

4.3.1. Emissions Quality Assurance

The spatial surrogates defined by STI (2001) and used to disaggregate area-source 

emissions were based on the CARB Statewide emissions domain. The Statewide 

domain is based on a Lambert Projection with a central meridian at 120.5 W and a 

horizontal resolution of 4-m. However, the SCOS modeling domain is based on a 

Lambert Projection with a central meridian at 118 W and a horizontal resolution of 5 km. 

The DTIM VMT grid was based on a Universal Transverse Mercator Projection (zone 

11) with a 5-km resolution. Quality assurance procedures were needed to ensure that 

the emissions were properly mapped into the SCOS modeling domain with no loss of 

mass. 

The quality assurance procedures were comprised of two parts. In the first part, 

emissions totals for the whole modeling domain were compared on a daily basis, by 

major component. In the second part, emissions inventory components were mapped 

in the SCOS modeling domain to ensure the proper spatial distribution. 

In this section, results from the July, 2005 episode period were presented as typical of 

all six episodes. The emissions components were generally defined by the emissions 

models used to develop the gridded emissions inventory. These included on-road 

mobile source emissions, biogenic emissions, other non-temperature-dependent 

sources ('area' sources), elevated point sources, and surface-level point sources. The 

surface-level point sources were small point sources with plume rises considered too 

small to exit the surface-layer modeled (~25 meters). 

It is difficult to compare exact totals for ROG emissions before and after they are 

processed for input into an air quality model. The various emissions models provide 

organic species as Total Organic Gases (TOG) which must be speciated into reactive 

organic gases (ROG) for the air quality model. Also, because of the complexity of 

organic species, they must be categorized and some information concerning molecular 

weight is lost. However, for carbon monoxide (CO) and nitrogen oxides (NOx) the 

chemical species are treated explicitly and there is no such confusion. Table 4-4 

summarizes emissions totals by major component for a selected weekday and a 

weekend day from the July, 2005 episode. Differences between preprocessed domainwide totals and model-ready totals for surface-level CO and NOx emissions were less 

than 1%. Differences between preprocessed elevated point sources and model ready 

elevated point source emissions were attributed to the fact that elevated point sources 

representing all of the counties within California were provided, and not all of them fell 

within the modeling domain. Emissions from those portions of the domain within Mexico 

were not included because their quality is poor (large uncertainties) and they were not 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE D-39 

considered important to ozone concentrations in the South Central Coast and South 

Coast Air Basins. 

Table 4-5 summarizes daily emissions totals for Ventura County, for the August 3-9, 

2005 episode for 2005 and 2012. The totals shown in Table 4-5 should only be 

considered approximate, but were typical for each of the six episodes. They are based 

on emissions gridded with a resolution of 4 km; which may not exactly represent political 

boundaries. Day-to-day differences can be attributed to differences between weekdays 

and weekend-days, and day-specific temperatures. 

Figures 4-10 through 4-14 show the spatial distribution for area sources, surface-layer 

point-sources, on-road mobile-sources, elevated point-sources, and biogenic sources. 

The gridded emissions had a resolution of 5-km. Therefore, it was difficult to show 

exact agreement between emissions and political or coastal boundaries. Also, the 

process of remapping emissions from one coordinate system to another causes the 

gridded emissions to spatially 'spread' slightly. 

Table 4-4: Emissions inventory domain-wide totals (ton/day) for a weekday and a 

weekend day 2005. 

 

Friday, July 15 

 Before Processing SAPRC99 Model-Ready 

 CO NOx TOG CO NOx TOG1/

area 1667 806 1716 1665 802 1628 

surf. point 126 75 233 126 75 230 

on-road 3816 868 432 3811 867 424 

elev. point 65 84 43 55 72 36 

biogenic -- -- -- -- -- 806 

Sunday, July 17 

 Before Processing SAPRC99 Model-Ready 

 CO NOx TOG CO NOx TOG1/

area 2422 685 1751 2407 682 1662 

surf.point 113 62 94 114 62 93 

on-road 3142 497 345 3138 497 340 

elev. point 51 80 40 42 69 32 

biogenic -- -- -- -- -- 825 

1/ TOG was calculated as the sum of ROG and CH4. 
Table 4-5 Daily emissions totals (ton/day) for Ventura County for selected days during the August 3-9

period for the year 2005 and the year 2012 baseline.  Wed,Aug.03 Thu,Aug.04 Fri,Aug.05 Sat,Aug.06  CO NOx TOG1/ CO NOx TOG1/ CO NOx TOG1/ CO NOx TOG1/ 

 On-Shore 2005 Statnry 23 12 70 23 12 70 23 12 70 20 9 63 Off-Road 70 25 15 70 25 15 70 25 15 110 19 21 On-Road 133 21 17 133 21 17 137 21 17 130 16 16 Biogen 0 0 76 0 0 74 0 0 53 0 0 52 Off-Shore 2005 Statnry <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 Off-Road 3 14 <1 3 14 <1 3 14 <1 3 14 <1  --- --- --- --- --- --- --- --- --- --- --- --- totals 229 72 178 229 72 176 232 72 155 264 58 153  On-Shore 2012 Statnry 24 12 69 24 12 69 24 12 69 32 8 62 Off-Road 70 18 12 70 18 12 70 18 12 100 15 19 On-Road 81 13 10 81 13 10 83 13 11 79 10 10 Biogen 0 0 76 0 0 74 0 0 53 0 0 52  Off-Shore 2012 Statnry <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 Off-Road 1 16 <1 1 16 <1 1 16 <1 1 16 <1  --- --- --- --- --- --- --- --- --- --- --- --- totals 178 59 168 178 59 167 180 59 146 213 48 143 1/ TOG emissions totals were estimated from the SAPRC99 model-ready files by  and CH4 

PAGE D-40 MAY 2008
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MAY 2008 PAGE D-41 

Figure 4-10 The spatial distribution of area-source NOx (g-mole/hour) emissions during 

a typical weekday at 1500 PDT, during the summer of 2005. 
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PAGE D-42 MAY 2008 

Figure 4-11 The spatial distribution of on-road, mobile-source NOx (g-mole/hour) 

emissions during a typical weekday at 1500 PDT, during the summer of 2005. The 

contour scale is logarithmic. 
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MAY 2008 PAGE D-43 

Figure 4-12 The spatial distribution of surface-level, point source NOx (g-mole/hour) 

emissions during a typical weekday at 1500 PDT, during the summer of 2005. The 

contour scale is logarithmic. 
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PAGE D-44 MAY 2008 

Figure 4-13 The spatial distribution of elevated, point-source NOx (g-mole/hour) 

emissions during a typical weekday at 1500 PDT, during the summer of 2005. The 

contour scale is logarithmic. 
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MAY 2008 PAGE D-45 

Figure 4-14 The spatial distribution of biogenic ROG (g-mole/hour) emissions during a 

typical weekday at 1500 PDT, during the summer of 2005. The contour scale is 

logarithmic. 
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MAY 2008 PAGE D-47 

5. BASE YEAR SIMULATION RESULTS

Table 3-1 (see Chapter 3) showed the days simulated for each of the six episodes 

selected by the SCAQMD. The first day of each episode was considered a 'spinup' day. 

Subsequent days were evaluated for air quality model performance and the suitability of 

each of the observed and simulated concentrations for use in the development of the 

ozone SIP for Ventura County. 

5.1. Base Year Results and Air Quality Model Performance Evaluation

The use of air quality models to develop an ozone SIP is based on the presumption that 

the results from these models suitably represent measured air quality. To assess this 

suitability, the U.S. EPA (2005) recommends that the results of the base-year simulation 

be evaluated against measured concentrations. This model performance evaluation 

should involve a number of evaluation procedures including statistical and graphical 

measures to compare measured and simulated pollutant concentrations and sensitivity 

analyses to evaluate the suitability of the model inputs. This chapter discusses results 

from the most pertinent of the evaluations completed and considered. 

5.1.1. Statistical Base-Case Evaluation

The U.S. EPA (1991) recommends statistical measures for evaluating the performance 

of air quality models. These include unpaired peak concentration ratio (UPR), mean 

normalized bias (MNB), and mean gross error (MGE). For ozone, these statistical 

measures compared measured and simulated ozone concentrations for monitoring sites 

with ozone concentrations of 60 ppb or greater. Under the U.S. EPA (1991) guidelines, 

the thresholds for acceptable model performance were UPR in the range of 0.80-1.20, 

MNB of +/- 15% and, MGE of 35% or less. 

The U.S. EPA (1991) recommends that statistical measures of model performance be 

calculated for the domain as a whole. However, for a modeling domain as large and 

complex as the SCOS domain, it was decided to divide the domain into subregions and 

evaluate model performance for each subregion independently (see Figure 4-1). 

Within the domain, Ventura County was represented by subregion 2 (SR002). During 

the years 2004 and 2005 period, six ozone monitoring sites were located in Ventura 

County (Figure 5-1). 

For each of the six episodes daily UPR, NMB, and MGE were calculated for Ventura 

County. Table 5-1 summarizes the statistical measures for evaluating ozone model 

performance for each day of the five episodes. The simulation results met U.S. EPA 

(1991) model performance thresholds for UPR, MNB, and MGE on 10 of the days. Of 

these, 6 were from the August 3-9, 2005 episode. As an example, the pattern of 

simulated ozone for August 6, at 1500 PDT is summarized in Figure 5-2. 
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PAGE D-48 MAY 2008 

Figure 5-1 Ozone monitoring sites in Ventura County during years 2004 and 2005. 

The sites are Ojai (3172), Emma Wood State Beach (2756), Rio Mesa (2991), Piru 

(2702), Simi Valley (2880), and Thousand Oaks (2984). 
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MAY 2008 PAGE D-49 

Table 5-1 Ozone model performance statistical measures for five 2004 and 2005 

episode, for Ventura County (SR0002). The statistical measures are Unpaired Peak 

Ratio (UPB), Mean Normalized Bias (MNB), and Mean Gross Error (MGE). The 

simulated daily 8-hour ozone concentration and the 8-hour observed concentrations are 

also shown. Statistical measures that met U.S. EPA (1991) performance thresholds are 

highlighted. 

 Sim. Sim. Obs. 

 1-hr 8-hr 8-hr 

 Episode Day UPR MNB MGE Pk.O3 Pk.O3 Pk.O3 

 -nd- % % ppb ppb ppb 

June, 2004 04 0.69 -36 36 65 56 86 

 05 0.69 -31 31 82 64 95 

 06 1.05 -16 16 92 75 82 

 07 0.88 -14 14 60 53 61 

August, 2004 04 0.95 -16 16 67 56 66 

 05 0.83 -30 30 76 61 77 

 06 0.90 -30 30 87 67 86 

 07 0.93 -20 20 93 66 79 

 08 0.37 -22 22 73 63 75 

May, 2005 18 0.82 -21 21 57 51 64 

 19 0.69 -30 30 58 51 72 

 20 -- -- -- <60 <60 53 

 21 0.64 -31 31 59 52 82 

 22 0.66 -34 34 62 56 84 

 23 0.88 -18 18 78 61 76 

 24 0.74 -27 27 68 58 76 

July, 2005 15 1.02 -19 24 108 79 89 

 16 1.03 -14 19 99 84 83 

 17 1.09 -15 17 100 79 85 

 18 0.81 -22 22 74 62 76 

 19 0.94 -24 24 94 69 85 

August, 2005 03 1.00 -07 13 91 81 85 

 04 1.01 -04 08 97 84 83 

 05 0.94 -10 16 105 91 94 

 06 0.96 00 14 98 90 93 

 07 1.09 +10 12 94 84 75 

 08 1.06 +05 14 95 86 80 

 09 1.21 +10 10 95 83 72 
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Table 5-1 (continued) 

August, 2005 26 0.93 -13 16 73 59 64 

 27 0.92 -16 17 69 61 68 

 28 0.72 -28 28 68 59 86 

 29 0.58 -41 41 57 51 85 

Figure 5-2 Measured (numbers) and simulated (contours) ozone concentrations on 

August 6, 2005 (DOY 218) at 1500 PDT. The minimum shaded contour is 60 ppb 

ozone and the contour intervals are 20 ppb ozone. 
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Figure 5-3 Comparison of measured (points) and simulated (lines) hourly ozone 

concentrations (ppb) from the August 3-9 episode base case simulation (mA01). The 

monitoring sites were Ojai (a), Piru (b), Simi Valley (c), Thousand Oaks (d), and Emma 

Wood State Beach (e). 

a) Ojai

b) Piru

c) Simi Valley

d) T.Oaks

e) Emma Wood
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Figure 5-4 Simulated and observed daily 1-hour ozone concentrations for Ventura 

County from the August 3-7, 2005 episode. The graphs show the results for August 4 

(a), August 5 (b), August 6 (c), and August (7). The lines in the plots represent a slope 

of 1. 

0 50 100 150

150

100

50

0

Observed (ppb)

Simulated (ppb)

a)

0 50 100 150

150

100

50

0

Observed (ppb)

Simulated (ppb)

b)

0 50 100 150

150

100

50

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Observed (ppb)

Simulated (ppb)

c)

0 50 100 150

150

100

50

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Observed (ppb)

Simulated (ppb)

d)

1-Hour Ozone Concentrations
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Simulated afternoon wind patterns in Ventura County consistently showed the 

development of a sea-breeze that drew air from over the Santa Barbara Channel across 

Ventura County. Except for the contribution of offshore shipping, this air would be 

expected to be relatively clean and devoid of ROG. Therefore, for most of the episodes, 

little ozone was simulated in the western part of the County (e.g., Ojai). The August 3-

9, 2005 episode showed the only exceptions to this pattern in the simulated wind fields. 

It was only during this episode that MM5 simulations showed easterly flow patterns in 

the Santa Barbara Channel and Santa Ynez Mountains that led to higher ozone 

concentrations in western Ventura County. 

At the eastern end of Ventura County (e.g., Simi Valley), for most of the episodes, the 

afternoon westerly flow encountered easterly flow in Los Angeles County. The resulting 

convergence zone created the conditions conducive to the formation of ozone 

Measured and simulated ozone concentrations at selected Ventura County sites are 

summarized in Figure 5-3 for the August 3-9, 2005 episode. Diurnal changes in 

measured ozone concentrations increased with distance from the coast and this pattern 

was replicated in the simulated concentrations. There was little diurnal change at 

Emma Wood State Beach, located on the coast. Inland, at such sites at Ojai and Simi 

Valley, simulated over-night ozone concentrations were somewhat higher than those 

observed; however, the day-time maximum ozone concentrations were well represented 

in the simulation results. 

For the August 3-9, episode, simulated 1-hour ozone concentrations showed generally 

good agreement with observed concentrations throughout Ventura County; particularly 

at higher concentrations (e.g., Figure 5-4). 

5.1.2. Sensitivity Analyses

Sensitivity analyses are air quality simulations for which base case inputs have been 

altered to assess the model response to those inputs. Sensitivity analyses are used to 

better understand the air quality model response to uncertainties in the inputs and to 

assess whether the air quality model is responding in an appropriate manner. This 

section reports on selected sensitivity analyses to assess model response to changes in 

boundary concentrations, meteorological variables, and emissions. These analyses 

were focused on the August 3-9, 2005 (DOY 214-221) and the July 15-19, 2005 (DOY 

196-200) episodes, representing the period of the best air quality model performance. 

5.1.2.1. Boundary Condition Sensitivity

The U.S. EPA (1991) recommends a 'clean-air' NOx concentration of 2 ppb. In the 

base case simulations, the NOx concentration was reduced to 0.1 ppb above 200 magl. 

The July, 2005 episode was run without anthropogenic emissions using the case base 

boundary concentrations and using boundary concentrations with 2 ppb for all lateral 

boundaries (the initial concentrations were not altered and NOx remained 0.1 ppb 

above 200 magl). 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE D-54 MAY 2008 

The simulation results without anthropogenic emissions and using the base case 

boundary concentrations resulted in maximum 8-hour ozone concentrations of 37 ppb 

within Ventura County (SR0002) and 42 ppb in the Inland Empire of the SCAB 

(SR0004 -- see Figure 4-1). With the increase in NOx concentrations to 2 ppb for all 

boundaries, the maximum ozone concentration in Ventura County was 44 ppb and 53 

ppb in the SR0004. The response to higher NOx concentrations on the boundary was 

likely greater in SR0004 than in Ventura because of greater biogenic emissions in the 

warmer SCAB. 

Considering all of the episodes, most of the episode days simulated underestimated 

ozone concentrations within Ventura County (see Table 5-1). The sensitivity analysis 

suggested that using the higher boundary concentration of NOx would increase 

simulated ozone concentrations and, could improve base case model performance. 

However, it would also result in higher future-year simulated concentrations, 

independent of the level of anthropogenic emissions. It is expected that the higher this 

lower limit, the more difficult it will be to demonstrate attainment using an air quality 

model. 

5.1.2.2. Meteorological Field Sensitivity

Simulated nighttime wind speeds tended to be higher than wind speeds measured in 

Ventura County, and the simulated air temperatures tended to be higher than those 

observed (see Section 4.3.). In this section, the wind and temperature fields used in the 

base case simulations were altered to investigate the air quality model response to 

these inputs. Adjustments (to wind and temperatures) do not reflect actual hour-by-hour 

differences. In that light, the factors used to make the adjustments are arbitrary. The 

model performance statistical measures for these simulations were compared to that of 

the base case (mA01) in Table 5-2. 

In first sensitivity simulation (mA02), the air temperatures within the modeling domain 

were decreased by 3 ̊ C to approximate the discrepancies between simulated and 

observed temperatures (see Figure 4-6). The reduced air temperatures resulted in a 

reduction in peak daily ozone concentrations of 5-6 ppb throughout Ventura County. 

This was equivalent to approximately 2 ppb ozone per degree. 

In the second sensitivity (mA03), the wind speeds throughout the domain were reduced 

by 20%. The reductions in wind speed resulted in an increase in ozone concentrations; 

however, the impact was less in western Ventura County (e.g., 3-8 ppb at Ojai) than in 

the eastern part of the County (e.g., 8-10 ppb at Simi Valley – data not shown). 

In the third sensitivity simulation (mA04) the vertical diffusivity fields were reduced to 

approximate reducing the afternoon mixing heights by half. The simulation results from 

reduced mixing heights were mixed. Maximum daily ozone concentrations (reflected in 

the URP) were reduced on August 4, but increased on August 6. However, the average 

simulated ozone concentrations (reflected in the MNB) were lower compared with those 

from the base case. On August 5, the base case MNB of -10% was reduced to -21%. 
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MAY 2008 PAGE D-55 

The likely cause of the lower ozone concentrations from the reduced mixing heights was 

the interaction between mixing heights and easterly wind flows aloft (e.g., see Figure 4-

6). The reduced mixing heights limited transport to the surface of the ozone and ozone 

precursors advected from Los Angeles County. This may also reflect limitations in the 

vertical resolution within MM5. However, while the mixing heights used in the basecase simulation may be over-estimated, the resulting transport from Los Angeles 

County to western Ventura County was adequately represented because the easterly 

flow was expected to be confined to below the mixing height. 

Table 5-2 Model performance statistical measures for 1-hour ozone concentrations, for 

selected sensitivity analyses based on alterations of the air temperature, wind, and 

mixing height fields during the August 3-9, 2005 episode.

 Aug 04 Aug 05 Aug 06 

 UPR1/ MNB1/ UPR MNB UPR MNB 

 -nd- % -nd- % -nd- % 

Base Case (mA01) 1.01 -04 0.94 -10 0.96 00 

Scaled Temp (mA02) 0.95 -10 0.89 -16 0.90 -06 

Scaled Wind (mA03) 1.13 +05 1.04 -04 1.06 +08 

Scaled MHgt (mA04) 0.96 -13 0.94 -21 1.08 -06 

1/ Unpaired Peak Ratio (UPR) and Mean Normalized Bias (MNB) 
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Table 5-3 Ozone model performance statistical measures for selected sensitivity 

analyses based on alterations of the August 3-9, 2005 base case emissions inventory. 

 Aug 04 Aug 05 Aug 06 

 UPR1/ MNB1/ UPR MNB UPR MNB 

 -nd- % -nd- % -nd- % 

Base Case (aA05) 1.00 -04 0.91 -10 0.94 00 

BC 0.75*NOx (aA06) 0.94 -08 0.88 -13 0.88 -04 

BC 1.25*NOx (aA07) 1.02 -03 0.90 -10 0.98 02 

BC 0.75*ROG (aA08) 0.95 -08 0.85 -14 0.90 -05 

BC 1.25*ROG (aA09) 1.05 00 0.97 -07 0.98 05 

No.Biogenic (aA10) 0.95 -10 0.87 -15 0.91 -03 

1/ Unpaired Peak Ratio (UPR) and Mean Normalized Bias (MNB) 

2/ The emissions inventory used for 'mA07' was an update of that used for 

 'mA04'. 

5.1.2.3. Emissions Inventory Sensitivity

The model sensitivity to emissions uncertainty was investigated by varying the base 

case anthropogenic emissions inventory for the August 3-9, 2005 episode. The impact 

of biogenic emissions on ozone concentrations in Ventura County was also evaluated. 

The August 3-9, 2005 base case emissions inventory was altered by scaling 

anthropogenic emissions NOx and ROG by factors of 0.75 and 1.25 respectively 

(i.e., +/- 25%). The simulations were running using these altered emissions inventories 

and the results compared with the base case model performance in Table 5-3. 

Simulations done in the Los Angeles Coastal Plain have often shown NOx detriment, 

wherein reductions in NOx emissions resulted in increase ozone concentrations. 

However, no such detriment were apparent in the sensitivity analyses done using the 

base case emissions inventory. Reductions in ROG or NOx emissions resulted in lower 

simulated ozone concentrations, and increases in ROG or NOx emissions resulted in 

higher ozone concentrations throughout Ventura County (similar simulations done for 

the July, 2005 episode showed little change in simulated ozone in response to NOx 

emissions changes, suggesting that insensitivity to NOx emissions may occur during 

different meteorological conditions – data not shown). 

The response of the model to removing the biogenic emissions was similar to removing 

anthropogenic ROG emissions (note: the biogenic emissions account for approximately 

25% of the TOG for Ventura County – see Table 4-5). The change in simulated ozone 

with the removal of biogenic emissions was only a little less than the reduction in 

anthropogenic ROG of 25%. The impact of the removal of biogenic emissions from the 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE D-57 

inventory varied only a little from day-to-day, but generally reduced simulated ozone 

concentrations at Simi Valley and Ojai by 3-5 ppb (data not shown). 
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6. PREDICTION OF FUTURE-YEAR DESIGN VALUES

6.1. Methodology

The U.S. EPA (2005) recommends that the results from air quality models be used to 

scale measured ozone design values to predict future-year 8-hour ozone 

concentrations. Using this approach, the ozone air quality model was run using 

emissions inventories for a “reference” year and then run a second time using 

emissions for a designated future-year. Measured ozone concentrations were used to 

calculate an 8-hour ozone design value at each monitoring site for the reference year. 

The ratio of the simulated concentrations at each site averaged for the future year and 

the average concentration for the reference year was calculated. This ratio, defined as 

the relative reduction factor (RRF), was multiplied by the reference-year design value to 

estimate the future year design value. 

For each episode, emissions from three years were needed. The first set of emissions 

represented the base year. For the episodes used in this analysis, the base year was 

either 2004 or 2005. The purpose of the simulations using the base year emissions was 

to evaluate ozone model performance. Only days from each episode that met model 

performance and concentration - threshold criteria were used in the calculation of the 

RRF. The results from the reference year, recommended by the U.S. EPA (2005) to be 

the year 2002, and the future year were used to calculate the future-year design value. 

For Ventura County, the targeted future-year was 2012. 

The U.S. EPA (2005) argues that the response of ozone air quality models to changes 

in emissions is approximately constant above a concentration of 85 ppb. Therefore, in 

an ideal study, only those days with simulated ozone concentrations of 85 ppb or 

greater would be used to calculate RRFs (in cases with limited data, 70 ppb may be 

used). To increase this likelihood, the U.S. EPA allowed the use of the maximum 

simulated ozone concentration within 15-km of each monitoring site to be used for this 

calculation. The U.S. EPA also recommended that at least 10 episode days be used for 

each site in the calculation of a RRF and set a minimum limit of 5 episode days. 

However, the number of episode days available, the number of days at each site with 

suitably high measured ozone concentrations, and air quality model performance impact 

the ability to meet this target in practice. 

6.2. 8-Hour Ozone Design Values

The 8-hour ozone design value for each monitoring site was based on the 4-th highest 

ozone concentration measured within a year, averaged over three years. However, the 

U.S. EPA (2005) allows for flexibility in the calculation of the reference year design 

value. The methodology adopted for this analysis was to calculate the 8-hour ozone 

design value for the year 2002 as the average of the design values for the years 2002, 

2003, and 2004 (effectively, a 5-year weighted average of the 4-th highest within each 

year). The results for Ventura County were summarized in Table 6-1. 
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6.3. Model Performance and Ozone Threshold Criteria

For use in projecting future-year design values, ozone simulation results should meet 

ozone model performance criteria and concentration thresholds. Section 5.1. 

summarizes statistical measures for evaluating base case model performance. To 

ensure that episodes are representative and that simulated concentrations are high 

enough to respond to emissions, the observed and simulated 8-hour ozone 

concentrations for each must site be 70 ppb or greater. In summary, therefore, for 

simulation results to be used in the calculation of a site-specific RRF, the following 

criteria were met: 

 1-hour model performance for the subregion in which each site is located must 

meet the U.S. EPA (1991) thresholds for UPR, MNB, and MGE. 

 the base year measured 8-hour ozone concentration must be 70 ppb or greater. 

 the reference year (e.g., 2002) simulated 8-hour ozone concentration within 15-

km of each site must be 70 ppb or greater. 

A review of model performance revealed that the August 3-9, 2005 episode was the 

only one of the six for which simulated ozone concentrations in western Ventura County 

(i.e., Ojai) were suitable for this analysis (data not shown – see also Figure 5-1). 

Therefore, results from only the August 3-9, 2005 episode were used in the calculation 

of relative reduction factors and the estimation of future-year ozone design values. 

6.4. Calculation of Site Specific RRFs and Future-Year Design Values

The RRF for each site in Ventura County violating the 8-hour ozone NAAQS (see Table 

3-1) was calculated based on the ratio of the average concentrations simulated for the 

year 2002, and the average concentration for the future year. The future-year 8-hour 

ozone design value was calculated as: 

 

DV SIM

SIM DV fy

fy 2002

2002

*

⎟

⎟

⎠

⎞

⎜

⎜

⎝

⎛

=
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MAY 2008 PAGE D-61 

Table 6-1 Weighted-averaged, eight-hour ozone design values (ppb) for the year 2002 

for those sites in violation of the 8-hour NAAQS for ozone. 

 Site 2002 2003 2004 Aver1/ 

---------------------------------------------------- 

Ojai 095 095 094 094 

Simi Valley 097 095 092 094 

Piru 085 090 088 087 

---------------------------------------------------- 

1/ The average was truncated to the nearest 'ppb'. 

Table 6-2 Observed and simulated daily 8-hour ozone concentrations at selected 

Ventura County monitoring sites (ppb). 

 Base 

 No. Case 

 Aug.3 Aug.4 Aug.5 Aug.6 Aug.7 Aug.8 Days Average RRF Design 

 ppb ppb ppb ppb ppb ppb Used ppb -nd- Value 

 ppb 

_______________________________________________________________________________

Site: Ojai

Obs. 2005 081 084 084 085 0692/ 0652/ 4 

Sim. 2002 071 076 076 081 079 078 076 0941/

Sim. 2012 068 072 071 076 074 071 072 0.95 089 

Sim. 2012a 068 068 069 074 071 069 071 0.93 087 

Site: Piru 

Obs. 2005 083 082 086 082 0682/ 070 5 

Sim. 2002 082 085 094 094 086 088 089 0871/

Sim. 2012 075 078 084 082 076 077 079 0.89 078 

Sim 2012a 073 075 082 078 074 073 076 0.85 075 

Site: Simi Valley

Obs. 2005 085 082 094 093 075 080 6 

Sim. 2002 083 088 095 100 097 099 094 0941/

Sim. 2012 077 082 090 090 085 087 085 0.90 085 

Sim. 2012a 076 080 091 087 080 082 083 0.88 083 

_______________________________________________________________________________ 

1/ The 8-hour design values for 2002 were from observations. 

2/ This day was not used in the RRF calculation because the ozone 

concentration was less than 70 ppb 

The average concentrations and year-specific relative reduction factors (RRF) shown in 

Table 6-2 for each site were calculated using days for which observed concentrations in 

2005 were 70 ppb or greater. The simulated ozone concentrations are the maximum 

daily concentration within 15 km of each site location. The simulation results represent 

the year 2005 base case ('Sim. 2005 – run to evaluate model performance only), the 

year 2002 base case emissions ('Sim. 2002'), the simulated year 2012 base case 

emissions ('Sim. 2012'), and the year 2012 controlled emission scenario ('Sim. 2012a'). 

Where DVfy is the future year design value, SIMfy is the simulated average 8-hour 

concentration for the future year, SIM2002 is the simulated average 8-hour concentration 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE D-62 MAY 2008 

for 2002, and DV2002 is the year 2002 8-hour ozone design value. The calculation of 8-

hour ozone design values for 2012 is summarized in Table 6.2. Year 2012 design 

values were calculated using two emissions inventory scenarios: the 2012 uncontrolled 

base case, and a 2012 project controls case. 

The results summarized in Table 6-2 suggest a maximum ozone 8-hour ozone design 

value at Ojai of 89 ppb in the year 2012 using the uncontrolled base case emissions 

and a design value of 87 ppb using the controlled base case emissions scenario. The 

U.S. EPA (2005) modeling guidelines allow a projected 8-hour ozone design value of 83 

to 87 ppb to be equivalent to an attainment demonstration with supplemental “weight of 

evidence" (WOE) analyses. 

6.5. Sensitivities of Relative Reduction Factors to Meteorological Inputs 

The sensitivity analyses summarized in Section 5.1.2. suggest that uncertainties in the 

input meteorological fields influenced the simulation results of the air quality model. In 

this section, the question of whether these uncertainties could impact projected futureyear ozone design values is addressed. The 2002 and 2012 base case emissions 

inventories for the August 3-9, 2005 episode were run with the perturbations in 

meteorological inputs introduced in Chapter 5. These included a decrease in air 

temperatures of 3 ̊ C, an approximate 50% reduction in the mixing height fields, and 

background NO concentrations of 2 ppb (see Section 4.2.). 

The results from the analyses suggested that uncertainties in the meteorological input 

fields for the air quality model can have a marked impact on estimated future-year 

design values. The perturbed air temperature and mixing height fields, and background 

NO concentrations resulted in differences of up to 5 ppb in estimated year 2012 design 

values. Although the results from only two sites were summarized in Table 6-3, it was 

apparent that the impacts were not uniformly distributed. This analysis suggests that 

further refinements in the meteorology fields used to run the air quality model could 

improve the estimation of future-year design values in Ventura County. 
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Table 6-3 Estimated year 2012 ozone design values for Ojai and Simi Valley using 

controlled emissions as function of adjustments to the air temperature and mixing height 

inputs to the air quality model. The relative reduction factors (RRF) were base on the 

simulation results averaged for August 4-6, 2005. The results in this table only 

approximated the more formal calculations used to calculate Table 6-2 and; therefore, 

did not show exact agreement. 

 

 Sim. Sim. Year 2012 

 2002 2012 RRF DV 

 ppb ppb -nd- ppb 

Site: Ojai 

 Base Case Met. 072 064 0.90 086 

 Scaled Temp. 067 060 0.90 084 

 Scaled M.Hgt 064 061 0.95 089 

 High NOx Bndy. 075 068 0.90 085 

Site: Simi Valley 

 Base Case Met. 088 075 0.85 080 

 Scaled Temp. 082 071 0.86 081 

 Scaled M.Hgt 082 075 0.91 085 

 High NOx Bndy. 092 080 0.87 081 

6.6. Sensitivity of Projected Future-Year Design Values to Emissions

The future-year 8-hour ozone design values calculated in Section 6.4. were determined 

using baseline planning emissions inventories for the year 2012. Future analyses were 

done to assess the response of these design values to future reductions in emissions 

inventories. In these analyses, the baseline anthropogenic ROG and NOx emissions for 

2012 were reduced in increments of 20% (e.g., 1.0, 0.8, 0.6, 0.4, and 0.2, respectively). 

The air quality model was run using each of the resulting 25 emissions inventories. 

From each simulation, the 8-hour ozone design values were calculated for Ojai and for 

Simi Valley using the procedures outlined in Section 6.4. The results were summarized 

as iso-surface plots of 8-hour design values (sometimes referred to and 'EKMA' plots). 

The results for 2012 are summarized in Figure 6-1. The concentration in the upperright-hand corner is the baseline 8-hour ozone design value calculated in Section 6.4. 

for the uncontrolled base case emissions. 
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PAGE D-64 MAY 2008 

 A) Year 2012 8-hour DV (ppb) for Simi Valley (Site ID 2880). 

 1.0| 70. 74. 78. 82. 85. 

 | 

 | 

 0.8| 69. 73. 77. 80. 83. 

 | 

 N | 

 O 0.6| 67. 71. 74. 77. 79. 

 X | 

 | 

 0.4| 63. 66. 68. 70. 71. 

 | 

 | 

 0.2| 54. 56. 57. 58. 58. 

 | 

 | 

 ----------------------------------------- 

 0.2 0.4 0.6 0.8 1.0 

 ROG 

 B) Year 2012 8-hour DV (ppb) for Ojai (Site ID 3172) 

 1.0| 77. 80. 83. 86. 89. 

 | 

 | 

 0.8| 77. 80. 83. 85. 87. 

 | 

 N | 

 O 0.6| 76. 78. 79. 81. 82. 

 X | 

 | 

 0.4| 71. 72. 73. 74. 75. 

 | 

 | 

 0.2| 62. 62. 63. 63. 63. 

 | 

 | 

 ----------------------------------------- 

 0.2 0.4 0.6 0.8 1.0 

 ROG 

Figure 6-1 Year 2012 8-hour ozone design values (ppb) in response to anthropogenic 

ROG and NOx emissions reduction for Simi Valley (A) and for Ojai (B). 
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MAY 2008 PAGE D-65 

7. REFERENCES 

CARB. 1992. "Technical Guidance Document: Photochemical Modeling". California Air 

Resources Board PTSD., Sacramento, CA. 95814. April, 1992. 

CARB. 1984. "California Surface Wind Climatology" California Air Resources Board. 

PTSD. Sacramento, CA. 95814. June, 1984. 

CARB, 2007. "Photochemical Modeling Protocol for Developing Strategies to Attain the 

Federal 8-Hour Ozone Air Quality Standard in Central California". California Air 

Resources Board PTSD. Sacramento, CA 95814. Draft May, 2007. 

DRI. 1999. "SCOS97-NARSTO 1997 Southern California Ozone Study and Aerosol 

Study – Volume I: Operational Program Plan". Desert Research Institute. Contract No. 

93-326. California Air Resources Board. Sacramento, CA. 95814. February, 1999. 

 

DRI. 1993. "Particulate and Gaseous Organic Receptor Modeling for the Southern 

California Air Quality Study". Desert Research Institute. Contract No. A832-132. 

California Air Resources Board. Sacramento, CA. 95814. November, 1993. 

ENVIRON. 2004. User's Guide – Comprehensive Air Quality Model with Extensions 

(CAMx). ENVIRON, Int. Corp. Novato, CA. 94945-5010. August, 2004. 

Grell, G., J. Dudhia, and D. Stauffer. 1993. "A Description of the fifth-generation Penn 

State/NCAR mesoscale modeling system (MM5). NCAR Technical Note NCAR/TN397+IA. National Center for Atmospheric Research, Boulder, CO. 80305. 

Lee, S.M., S. Mitsutomi, and J. Cassmassi. 2007. "Improvement of MM5 simulations for 

CAMx in Southern California," 2007 Ad Hoc meteorological Modeling Group Meeting. 

U.S. EPA. June, 2007. 

(see http://www.ladco.org/tech/photo/adhocmet/adhoc2007agenda.htm). 

Newchurch, M, M. Ayoub, S. Oltmans, B. Johnson, and F. Schnidlin. 2003 Vertical 

distribution of ozone at four sites in the United D=States. J.Geophys. Res. (108)NO.D1, 

4031, doi:10.11/1029/2002JD002059. 

SCAG. 2006. Personal Communication. Southern California Association of 

Governments. Los Angeles, CA. 90017. November, 2006 

SCAQMD. 2007. "2007 Air Quality Management Plan. Appendix V: Modeling and 

Attainment Demonstrations". Draft. South Coast Air Quality Management District. 

Diamond Bar, CA. January, 2007. 

SCAQMD 2006. CAMx v4.4beta. Personal Communication. South Coast Air Quality 

Management District. Diamond Bar, CA. 
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PAGE D-66 MAY 2008 

Scott, K. and M. Benjamin. 2003. Development of a biogenic volatile organic 

compounds emissions inventory for the SCOS97-NARSTO domain. Atmos. Environ. 

(37) Sup, No. S39-S49. 

STI. 2001. "Development of Gridded Spatial Allocation Factors for the State of 

California". Sonoma Technology, Inc. Technical Memorandum STI-900201/999542-

2092-TM. California Air Resources Board, EB. Sacramento, CA., 95814. July, 2001. 

U.S. EPA. 2005. "Guidance on the Use of Models and Other Analyses in Attainment 

Demonstrations for the 8-hour Ozone NAAQS". U.S. EPA OAQPS/ EMAD/AQMG. EPA454/R-05-002. RTP, NC. 27711. October, 2005 

U.S. EPA. 1991. "Guideline for Regulatory Application of the Urban Airshed Model". 

U.S. EPA OAQPS. EPA-450/4-91-013 RTP, NC 27711. July, 1991.
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VENTURA COUNTY WEIGHT OF EVIDENCE ASSESSMENT 

2/1/2008 

(mln/gms/klm) 

Prepared for 

Ventura County Air Pollution Control District 

Ventura, California 93003 

Prepared by 

California Environmental Protection Agency 

California Air Resources Board 

Planning and Technical Support Division 

Sacramento, California 95814
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1. INTRODUCTION 

Ventura County is currently classified as a Moderate nonattainment area for the federal 

8-hour ozone standard and has a nominal attainment date of June 15, 2010. The 

Ventura County Air Pollution Control District is requesting a reclassification to Serious, 

with an attainment date of June 15, 2013. Air quality analyses show that while progress 

in this area has been significant, it has slowed over the last several years, lending 

uncertainly to the current 2010 attainment date. Furthermore, the photochemical 

modeling analyses indicate that attainment will not occur by 2010. However, the 

photochemical modeling results do, in combination with the supporting Weight of 

Evidence analyses, support a 2013 attainment date. The following chapters describe 

the air quality, emissions, and modeling analyses that support the County’s 

reclassification as Serious and to support the overall conclusion that Ventura County will 

attain the federal 8-hour ozone standard by 2013. 

U.S. EPA has provided guidance on how to interpret the attainment deadline when 

attainment is measured by calendar year and the deadline is on June 15 – in the middle 

of the calendar year. U.S. EPA guidance calls for the analysis of attainment to be done 

for the year prior to the actual attainment year. The analyses summarized in this report 

evaluated emission and air quality projections for 2012, the year prior to the 2013 

attainment deadline. 

2. U.S. EPA ATTAINMENT DEMONSTRATION REQUIREMENTS 

The attainment demonstration portion of a SIP consists of the analyses used to 

determine whether a proposed control strategy provides the reductions necessary to 

meet the NAAQS by the attainment year. The Ventura attainment demonstration 

includes photochemical modeling which predicts the statewide emissions control 

strategy will result in an 8-hour design value of 0.087 parts per million (ppm) in 2012. 

This is just above the federal attainment level of 0.084 ppm. Because of the 

uncertainties inherent in photochemical modeling, the U.S. EPA allows states to 

supplement the model results with a Weight of Evidence (WOE) demonstration when 

photochemical modeling predicts ozone levels of 0.082 ppm to 0.087 ppm. 

The WOE assessment provides a set of complementary analyses that supplement the 

SIP-required modeling. These analyses can include consideration of measured air 

quality, emissions, and meteorological data, as well as evaluation of other air quality 

indicators and additional air quality modeling. All analysis methods have inherent 

strengths and weaknesses. However, examining an air quality problem in a variety of 

other ways helps offset the limitations and uncertainties that are inherent in all air quality 

modeling. 

The scope of the WOE analysis is different for each nonattainment area. The level of 

detail appropriate for each area depends upon the complexity of the air quality problem, 

how far into the future the attainment deadline is, and the amount of data and modeling 
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PAGE D-70 MAY 2008 

available. This document summarizes the analyses that comprise the WOE 

assessment for the Ventura County nonattainment area. 

3. HISTORICAL CONTEXT 

Ventura County is located west of Los Angeles County and is bordered by Kern County 

to the north, Santa Barbara County to the west, and the Pacific Ocean to the southwest. 

It includes the Channel Islands National Park and serves as a gateway to this five-island 

marine sanctuary. The federal 8-hour nonattainment area includes all of Ventura 

County, with the exception of the Channel Islands. 

The County has a combination of undeveloped and agricultural lands, as well as 

developed urban areas. As shown in Figure 1, the Los Padres National Forest, located 

in the northern portion of Ventura County, accounts for almost half the County’s land 

area. The County’s diverse economic base also includes biotechnology, 

telecommunications, and manufacturing activities, as well as tourism and military testing 

and development. 

Ozone in the Ventura County nonattainment area results from locally generated 

emissions, as well as the transport of ozone and ozone precursors from outside the 

County. Previous analyses by ARB staff have shown that emissions and pollutants 

transported from the South Coast Air Basin contribute to the ozone problem in Ventura 

County under certain meteorological conditions. Furthermore, ozone precursor 

emissions in the Los Angeles County portion of the South Coast Air Basin, which lies 

directly east of Ventura County, are nearly ten times the level of those in Ventura 

County. As a result, transported emissions can have a significant impact on Ventura 

County’s air quality. Additionally, Ventura County’s ozone air quality is impacted by 

emissions from shipping and related operations -- both in-port and off-shore. 
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Figure 1 Ventura County Land Area 

 

 
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The Ventura County and South Coast districts have some of the most stringent 

emissions control programs in the State. Local, State and federal control programs 

together have resulted in dramatic improvements in ozone air quality over the last 

18 years. The number of federal 8-hour exceedance days decreased 85 percent 

between 1988 and 2006. Ambient concentrations declined about 30 percent during this 

same period, as indicated by changes in the maximum concentration, the design value 

(an average of the fourth highest value in each of three consecutive years), and the 

mean of the Top 30 (the mean of the 30 highest 8-hour ozone concentrations recorded 

each year; see Figure 2). 

Figure 2 Ventura County Ozone Statistics 1988 to 2006 

 

Ventura County Ozone Statistics

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0.20

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

Year

Ozone (ppm)

0

12

24

36

48

60

72

84

96

108

120

Number of Days

Maximum Concentration Design Value Mean Top 30 Concentrations Exceedance Days

4. ASSESSMENT OF RECENT AIR QUALITY TRENDS 

4.1. General Basinwide Perspective 

Similar to the long-term historical trends described in the previous chapter, trends for all 

air quality indicators have continued to show substantial declines over the last decade 

(1995 compared with 2006). Since 1995, there has been: 

• A 75 percent decrease in the number of exceedance days (67 days in 1995 

versus 17 days in 2006). 

• A 30 percent decrease in the maximum ozone concentration. 

• An approximately 25 percent decrease in both the design value and the mean 

Top 30. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE D-73 

Because of these improvements, Ventura County is now close to attaining the federal 

8-hour standard. Ten years ago, the County’s design value was nearly 40 percent 

above the standard, and design values for all monitoring sites exceeded the federal 

standard. In contrast, 2006 data show that five of the County’s seven ozone monitoring 

sites now have design values that meet the standard, while the remaining two exceed 

the standard by less than 10 percent. The five sites that now meet the standard are 

El Rio (attained in 1997), Ventura-Emma Wood State Beach (attained in 1998), 

Thousand Oaks (attained in 2001), Ventura County-W Casitas Pass Road (attained in 

1999; site closed in 2002), and Piru (attained in 2006). The Ojai and Simi Valley 

monitoring sites have had similar design values over the last five years, ranging from 

about 15 percent above the standard in 2002 to less than 10 percent above the 

standard in 2006, when both sites had a design value of 0.09 ppm. 

Based on preliminary 2007 data, it appears ozone is continuing to improve. Through 

December 31, 2007, there were only 6 exceedance days: 5 days exceeding only at 

Simi Valley and 1 day exceeding at both Simi Valley and Thousand Oaks. This 

compares with 17 exceedance days during 2006. In addition, design values continue to 

move closer to the standard, with a 2007 design value of 0.088 ppm for Simi Valley and 

0.085 ppm for Ojai. 

 

Another way to look at the improvement in air quality is to map the change in the 

number of exceedance days. The maps in Figure 3 are based on monitoring data and 

show the reduction in the number of days exceeding the federal 8-hour standard over 

the last decade (1995 to 2005). This approach provides an estimate of the change in 

the spatial extent of the ozone problem. Ten years ago (1993 to 1995 map), only a 

small portion of the County near the coast had 5 or fewer exceedance days. The 

number of days increased as one moved inland. The worst areas, located along the 

northern and eastern borders of Ventura County, had more than 20, and in limited 

areas, more than 50 federal exceedance days. 

Today (2003 to 2005 map), the area with 5 or fewer exceedance days is much larger, 

encompassing the entire coastal area and extending inland. Most of the rest of the 

County lies within the range of 6 to 10 exceedance days. The areas 

with the worst ozone air quality are still located along the portions of the County that 

border the San Joaquin Valley and South Coast air basins, and these areas may be 

impacted by emissions and pollutants from outside the County. However, the ozone air 

quality in these transport-impacted border areas has improved since 1995 and is 

expected to continue improving with implementation of South Coast and statewide 

emissions control strategies. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE D-74 MAY 2008 

Figure 3 Ventura County Change in Federal 8-Hour Exceedance Days 1995 to 2005 

 

Ventura County

Federal 8-Hour Exceedance Days

 

4.2. Regional Analysis 

Historically, Simi Valley has been the high site in Ventura County, both in terms of 

ozone concentrations and number of exceedance days. In contrast, Ojai had much 

lower concentrations, as well as a lower number of exceedance days. 

Although Ojai still has fewer exceedance days, the design value for Ojai has been either 

similar to or equal to that for Simi Valley during the last five years. 

Figure 4 shows the number of exceedance days during 1995 and 2006 for all of Ventura 

County, as well as Simi Valley and Ojai, individually. The Simi Valley and Ojai sites are 

both located in inland valleys, in the eastern and western 

portions of the County, respectively. Although the populations of the two areas are very 

different (Simi Valley has more than ten times the population of Ojai), ozone 

concentrations have been very similar during the last several years. As shown in 

Figure 4, the number of countywide exceedance days decreased 75 percent between 

1995 and 2006. The decrease at Simi Valley was slightly higher (80 percent), while the 

decrease at Ojai was slightly lower (70 percent). In addition to these substantial 

decreases in exceedance days, the maximum concentration at Simi Valley decreased 

30 percent, and the design value decreased 25 percent between 1995 and 2006. In 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE D-75 

contrast, Ojai showed a much slower rate of improvement in these two indicators: less 

than 10 percent decrease in both from 1995 to 2006. The overall decrease at Ojai is 

smaller, in part, because concentrations at Ojai were at a lower level than at Simi Valley 

during 1995, but now the levels at these two sites are fairly comparable. 

Figure 4 Ventura County Change in Number of Federal 8-Hour Exceedance 

Days by Region 1995 and 2006 

5. ADDITIONAL SUPPORTING ANALYSES 

Prior to completion of the photochemical air quality modeling, ARB staff completed a 

rollback analysis to estimate Ventura County’s design value in 2010, the deadline for 

Moderate nonattainment areas. The rollback analysis evaluated the response of the 

design value to emissions reductions over the prior ten-year period. In addition to the 

rollback, staff completed several other air quality analyses aimed at evaluating potential 

attainment dates. These analyses are also described below. 

5.1. Rollback Analysis 

Staff completed a rollback analysis for Ventura County to determine what the future 

year design value would be. Before applying rollback, ARB staff calculated the ratio 

between emissions changes (ROG and NOx, combined) and 8-hour ozone design 

values. For Ventura County, this ratio was 1.1 to 1. In other words, a 1.1 percent 

change in combined emissions results in a 1 percent change in design value. 

Existing control programs are expected to reduce the County’s ROG and NOx 

emissions by about eight and ten percent, respectively, by the year 2010. Based on 

Number of Ozone Exceedance Days 

During 1995 and 2006

0

10

20

30

40

50

60

70

80

Ventura County

Simi Valley

Ojai

# of Exceedance Days

1995 2006
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE D-76 MAY 2008 

Ventura County’s 2005 design value of 0.091 ppm, and using a rollback analysis that 

accounts for a background concentration of 0.040 ppm in calculating the design value, 

this level of emissions reductions is expected to lower Ventura County's design value to 

0.076 ppm in 2010. However, results of the rollback analysis should be viewed with 

caution because the analysis is based on the mix of pollutants occurring in the past. It 

therefore embodies a significant degree of uncertainty. In contrast, the design value 

predicted by photochemical modeling reflects anticipated changes in the NOx and ROG 

mixture. 

5.2. Additional Air Quality Analyses 

Using the mean of the Top 30 concentrations each year and regression equations 

based on design values, ARB staff evaluated whether the rate of progress both 

historically and in recent years supports attainment in 2012 and beyond. The two 

indicators were evaluated for both high sites in Ventura County: Simi Valley and Ojai. 

5.2.1. Mean of the Top 30 8-Hour Ozone Concentrations 

The mean of the Top 30 represents the mean of the 30 highest 8-hour ozone 

concentrations measured at a site during each year and reflects the change in the 

average ozone concentration on the 30 worst days. Although the mean of the Top 30 is 

not directly related to the federal standard, it does provide a stable indicator that is not 

highly influenced by year-to-year changes in meteorology. Figure 5 shows the mean of 

the Top 30 trends for both Simi Valley and Ojai. Since 1988, the mean of the Top 30 at 

Simi Valley has declined 30 percent, from a concentration of 0.123 ppm in 1988 to 

0.084 ppm in 2006. While there was some variability in the trend during the early years, 

there has been a steady downward trend since 1995. The decrease at Ojai has been 

about half as much, or about 15 percent: from 0.096 ppm in 1988 to 0.081 ppm in 

2006. Although the mean of the Top 30 for Ojai was lower than for Simi Valley during 

the earlier period, concentrations at Ojai increased during the early 2000s. During the 

last several years, values for both sites have been similar. 

 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE D-77 

Figure 5 Mean of Top 30 8-Hour Ozone Concentrations at Simi Valley and Ojai 

As a way of gaining further insight into how the mean of the Top 30 has changed over 

time, the rate of change, relative to the start year, was also evaluated. For this 

evaluation, 3-year averages of the yearly values were normalized to the first year by 

calculating the ratio of the 3-year average of the mean Top 30 concentration to the 1990 

3-year average of the mean Top 30 concentration. Three-year averages of the 

normalized rate of progress values are plotted in Figure 6. Throughout most of the 

period, both sites have shown relatively steady progress towards lower mean Top 30 

concentrations, although the rate of progress at Ojai has been somewhat slower. 

Nevertheless, based on the trend lines, it appears the downward trends will continue. 

With continued emissions reductions, additional improvements in ozone air quality are 

expected over the next several years, bringing Ventura County to its attainment goal. 

 

 

Ventura County Sites

Mean of Top 30 Ozone Concentrations

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

Year

Ozone (ppm)

Simi Valley Ojai
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE D-78 MAY 2008 

Figure 6 Mean of Top 30 8-Hour Ozone Concentrations at Simi Valley and Ojai 

Normalized to the 1988-1990 3-Year Average 

 

Normalized 3 - Year Average Rate of Change of the Mean Top 30 Ozone Concentrations

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

Year

Ratio of Concentrations

Simi Valley Ojai

5.2.2. Design Value Regression Analyses 

In addition to evaluating the trends in the mean Top 30 concentrations, ARB staff also 

completed a regression analysis of design values for both Simi Valley and Ojai. 

Figures 7 and 8 show the trend in federal 8-hour design values for Simi Valley and Ojai, 

respectively. The regression line for the design values is also plotted and can be used 

to assess an expected attainment year, given a continuation of the recent rate of 

progress. The r2 values for the regressions were relatively high for both sites (0.93 for 

Simi Valley and 0.74 for Ojai). Based on the regression lines, an attainment year was 

calculated for each site. At Simi Valley, the design value is estimated to reach 

0.084 ppm in 2009, while the design value at Ojai is estimated to reach attainment by 

late 2010. Although there are a number of uncertainties associated with this approach, 

it indicates that attainment will not occur prior to 2010. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE D-79 

Figure 7 Simi Valley Federal 8-Hour Ozone Design Value and Linear Regression Line 

Note: “r2” is the square of the sample correlation coefficient, which is a measure of 

 the ability of the variable on the x-axis to explain the variable on the y-axis. 

Figure 8 Ojai Federal 8-Hour Ozone Design Value and Linear Regression Line 

Note: “r2” is the square of the sample correlation coefficient, which is a measure of 

 the ability of the variable on the x-axis to explain the variable on the y-axis.

Federal 8-Hour Ozone Design Value and Regression Line for Ojai

0.04

0.05

0.06

0.07

0.08

0.09

0.10

0.11

0.12

0.13

0.14

1990

1991

1992

1993

1994

1995

1996+

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

Year

Ozone (ppm)

Design Value Linear Regression (Design Value)

Equation of Trendline

y = -0.0011x + 0.1069

Equation will equal .084 in late 2010

r

2

 = 0.74

Federal 8-Hour Ozone Design Value and Regression Line for Simi Valley

0.04

0.05

0.06

0.07

0.08

0.09

0.10

0.11

0.12

0.13

0.14

1990

19911992

1993

19941995

19961997

1998

1999

2000

2001

2002

2003

2004

2005

2006

Year

Ozone (ppm)

Design Value Linear Regression (Design Value)

Equation of Trendline

y = -0.0024x + 0.1298

Equation will equal .084 in 2009

r

2

 = 0.93
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PAGE D-80 MAY 2008 

6. EMISSIONS AND PRECURSOR TRENDS 

Reactive organic gases (ROG) and oxides of nitrogen (NOx) are precursors to ozone. 

Emissions controls have significantly reduced the amounts of these 

precursors in the ambient air. These reductions have resulted in greatly improved 

ozone air quality. The following sections describe the ROG and NOx emissions trends 

in Ventura County since 1994, as well as the amounts of these precursors measured in 

the ambient air. 

6.1. Emissions Trends 

Emissions controls have substantially reduced the amounts of both ROG and NOx 

emitted by various sources throughout Ventura County. Figure 9 shows the estimated 

countywide trend in the precursor emissions from 1995 to 2006. The totals reflect 

estimates for the summer season in tons per day and include emissions from natural 

biogenic sources. Also included are offshore emissions out to a distance of 24 miles. 

Since 1995, there has been a fairly steady decrease in both ROG and NOx emissions, 

and the relative amounts of the two precursors have remained fairly constant over the 

twelve years. Overall, the emissions estimates show about a 20 percent decrease in 

both ROG and NOx emissions between 1995 and 2006. 

Figure 9 Ventura County Estimated ROG and NOx Emissions 1995 to 2006 

 

6.2. Precursor Trends 

The decrease seen in the estimated emissions trend is supported by the ambient 

trends, as well. Figure 10 shows levels of ROG and NOx measured in the ambient air 

at Simi Valley and El Rio, the two sites in the County with long-term records for both 

precursors. The data plotted were collected from the Photochemical Assessment 

Ventura County ROG & NOx Emissions - Summer SIP Inventory - Ver 1.06

with HHDD Correction, Off-Shore Emissions, and Biogenics

0

20

40

60

80

100

120

140

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006

Year

Tons/Day

Ventura County ROG Ventura County NOx
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MAY 2008 PAGE D-81 

Monitoring Stations or PAMS sites, and they reflect measurements collected from 

5 a.m. to 7 a.m. during July and August. Although the ROG trends are quite variable, 

most likely reflecting year-to-year changes in meteorology, the trend lines generally 

show overall reductions in both precursors at both sites. Ambient ROG decreased at a 

slower rate than NOx at the Simi Valley site. In contrast, ambient ROG decreased at 

about twice the rate of NOx at the El Rio site. The spatial and temporal scales of the 

trends are very different, making it difficult to resolve the differences between the 

emissions estimates and the ambient PAMS measurements. The important point is that 

the emissions trends and the ambient trends both indicate that ROG and NOx 

precursors have decreased over time and these decreases have resulted in improved 

ozone air quality. 

Figure 10 Simi Valley and El Rio Summer Morning Average ROG and NOx 

from PAMS Network Stations 

7. PHOTOCHEMICAL MODELING RESULTS 

The U.S. EPA (2005) provided criteria for calculating future-year ozone design values 

using air quality simulation results. Among these criteria were recommendations for air 

quality model performance, observed and simulated ozone concentration thresholds, 

and the number of simulated days used to estimate the relative reduction factors 

(RRFs), which are used to project design values from a specific reference year to a 

future year. All of these criteria were met for Ventura County, with the exception of the 

number of days used for some sites. 

The U.S. EPA (2005) recommends that at least 5 days be used at each site for 

calculating RRFs. However, because of the limited number of days with high ozone 

July-August Average Ambient PAMS ROG and NOx

at Ventura County PAMS Stations (5-7am)

0

50

100

150

200

250

300

350

400

450

500

1995 1996 1997 1998 1999 2000 2001 2002

Year

ppbC or ppbN

Simi Valley - ROG El Rio - ROG Simi Valley - NOx El Rio - NOx
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

PAGE D-82 MAY 2008 

concentrations and the limited success simulating high ozone in Ventura County, this 

number was difficult to meet. Six episodes totaling 34 days were modeled. Using the 

criteria outlined by the U.S. EPA (1991) to statistically compare observed and simulated 

ozone concentrations, suitable model performance for Ventura County was attained for 

10 of the days. One additional criterion was also applied: the simulated and observed 

8-hour ozone concentrations at each site had to be 0.070 ppm or greater. From this 

analysis, it was determined that simulation results from four days could be used in 

calculating the RRF for Ojai, five days for Piru, and six days for Simi Valley. 

Using the year 2012 emissions inventory reflecting a controlled emissions scenario, the 

simulation results were used to calculate 8-hour ozone design values. These results 

projected year 2012 design values of 0.087 ppm at Ojai, 0.077 ppm at Piru, and 0.085 

ppm at Simi Valley. Because of the uncertainties associated with air quality modeling, 

the U.S. EPA (2005) guidelines allow projected 8-hour ozone design values within the 

range of 0.082 ppm to 0.087 ppm as a demonstration of attainment when accompanied 

by supporting Weight of Evidence analyses. 

8. SUMMARY

U.S. EPA guidance allows the use of a Weight of Evidence analysis when 

photochemical modeling does not demonstrate attainment, but indicates an attainment 

year design value of 0.087 ppm or below. Photochemical modeling results indicate a 

design value of 0.087 ppm for Ventura County by 2013, the attainment date for Serious 

nonattainment areas. Based on photochemical modeling, as well as supporting 

analyses completed as part of the WOE evaluation, attainment by 2013 can be 

projected because of the following factors: 

 Between 1988 and 2006, the number of federal 8-hour exceedance 

days in Ventura County dropped 85 percent, and other indicators, 

including design value, maximum concentration, and mean of the 

Top 30 concentrations decreased about 30 percent. The 

decreases in these trend indicators have been fairly steady over 

time, and the downward trend is expected to continue with 

continued emissions reductions. 

 During the mid-1990s, the ozone problem in Ventura County was 

widespread. Since then, the design values at a number of sites 

have been reduced to levels below the standard. Currently, only 

Simi Valley and Ojai have design values that exceed the standard, 

and concentrations at both sites are decreasing. 

 The spatial extent of relatively clean areas has expanded over the 

last decade. The most populated areas of the County now have an 

average of 10 or fewer exceedance days per year. 
FINAL 2007 AIR QUALITY MANAGEMENT PLAN

MAY 2008 PAGE D-83 

 The mean of the Top 30 concentrations at Simi Valley and Ojai 

continue to decline, albeit at a slower rate at Ojai, as compared with 

Simi Valley. Based on historical progress, the declines are 

expected to continue. 

 Emissions estimates and ambient precursor data show that both 

ROG and NOx have declined, demonstrating the effectiveness of 

past emissions reductions. In addition, emissions estimates 

indicate a continued decline in precursor emissions over the next 

decade. 

 In addition to emissions reductions in Ventura County, precursor 

emissions are estimated to continue decreasing in the South Coast 

Air Basin, which will contribute to lower ozone concentrations in the 

transport-impacted areas of Ventura County. 

 Results of the enhanced rollback analysis show a design value of 

0.076 ppm for Simi Valley in 2010, assuming an average 

background concentration of 0.040 ppm and reductions in ROG 

and NOx emissions of 8 percent and 10 percent, respectively, 

between now and 2010. 

 In contrast, regression analyses based on design values show that 

attainment in Ventura County is not expected before 2010, but can 

be expected to occur by 2012. 

 Photochemical modeling shows a design value of 0.087 ppm for 

Ventura County in 2012, which is close to attainment and within the 

range of a WOE attainment demonstration. 

In summary, given the uncertainty in photochemical modeling, taken together 

with the significant air quality progress that has already occurred, and the 

result of the rollback and regression analyses which suggest attainment by 

2012, the overall WOE analysis indicates that Ventura County can expect to 

attain the federal 8-hour ozone standard by 2013, the required attainment 

date for Serious nonattainment areas. 
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