Staff Report

on

Proposed Revisions to the 8-Hour Ozone

State Implementation Plan for the

Sacramento Federal Nonattainment Area

Release Date: October 22, 2013

Hearing Date: November 21, 2013
Electronic copies of this document can be found on ARB’s website at 

http://www.arb.ca.gov/planning/sip/sip.htm. Alternatively, paper copies may be obtained 

from the Public Information Office, Air Resources Board, 1001 I Street, Visitors and 

Environmental Services Center, 1st Floor, Sacramento, California 95814, 

(916) 322-2990.

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This document has been prepared by the staff of the California Air Resources Board. 

Publication does not signify that the contents reflect the views and policies of the Air 

Resources Board, nor does a reference to trade names or commercial products 

constitute endorsement or recommendation for use.
Proposed 8-Hour Ozone State Implementation Plan Revisions

for the Sacramento Metropolitan

1997 8-Hour Ozone Federal Nonattainment Area

Table of Contents

Executive Summary .................................................................................................. ES-1

1. Implementing the 2009 Plan .................................................................................... 1

2007 State Strategy Implementation............................................................................ 1

Clean New and In-Use Heavy-Duty Trucks.............................................................. 4

Cleaner In-Use Off-Road Equipment ....................................................................... 4

Advanced Clean Cars .............................................................................................. 4

Expanded Passenger Vehicle Retirement................................................................ 5

Improvements and Enhancements to California’s Smog Check Program................ 5

Accelerated Introduction of Cleaner Line-Haul Locomotives.................................... 5

Consumer Products ................................................................................................. 5

Local Strategy Implementation .................................................................................... 6

2. Attainment Demonstration........................................................................................ 7

SIP Emissions Targets ................................................................................................ 7

Updated Attainment Demonstration............................................................................. 7

3. Other Clean Air Act Planning Requirements .......................................................... 11

Emission Inventory .................................................................................................... 11

Emission Reduction Credits....................................................................................... 12

Reasonable Further Progress Demonstration ........................................................... 12

Transportation Conformity Budgets ........................................................................... 13

Reasonably Available Control Measures Analysis..................................................... 13

Ozone VMT Offset Demonstration............................................................................. 14

Staff Recommendations ............................................................................................ 14
Appendix A ARB Rulemaking...................................................................................A-1

Appendix B Attainment Demonstration Analysis.......................................................B-1

Appendix C Emission Inventory Update .................................................................. C-1

Appendix D Reasonable Further Progress .............................................................. D-1

Appendix E Transportation Conformity Baseline Adjustments..................................E-1

Appendix F Unmonitored Area Analysis...................................................................F-1
Executive Summary

Purpose

This 2013 State Implementation Plan (SIP) Revisions to the Sacramento Regional 

8-Hour Ozone Attainment and Reasonable Further Progress Plan (2013 Update) 

updates the Sacramento Regional 8-Hour Ozone Attainment and Reasonable Further 

Progress Plan State Implementation Plan that was adopted and submitted the U.S. 

Environmental Protection Agency (U.S. EPA) as a SIP revision in 2009 (2009 Plan). 

The 2009 Plan outlines a strategy for achieving the 1997 8-Hour Ozone National 

Ambient Air Quality Standard (NAAQS or 8-hour standard) in the Sacramento

Metropolitan’s 8-Hour Ozone Nonattainment Area (Sacramento Nonattainment Area). 

The 2013 Update incorporates updated emission inventories, regulations, and the 

effects of the recession not included in the 2009 Plan.

Staff’s analysis indicates that actions taken by the local air districts and California’s Air 

Resources Board (ARB or Board) since the 2009 Plan was submitted will provide the 

reductions needed to attain the ozone standard by the 2018 deadline. This update 

provides information needed to support U.S. EPA approval of the Sacramento region’s 

plan for attainment of the 1997 8-hour ozone standard.

Attainment Demonstration and Other Requirements

State law assigns ARB the primary responsibility to ensure California's compliance with 

the federal Clean Air Act (CAA or Act). Traditionally, ARB shares that responsibility with 

local air districts through regulatory actions, incentive programs, and defined SIP 

commitments for further action to achieve emission reductions necessary for attainment. 

The State also has an expectation that the federal government will provide necessary 

emission reductions from sources under U.S. EPA’s authority.

ARB and the five local air districts that make up the Sacramento Nonattainment Area

made SIP commitments necessary to demonstrate attainment of the 8-hour ozone 

standard in the ARB 2007 State Strategy and in local SIP revisions. The 2013 Revision 

to the Sacramento Regional 8-Hour Ozone Attainment and Reasonable Further 

Progress Plan shows that the regulations that have been adopted and submitted to 

U.S. EPA will, in 2018, provide the emission reductions called for in the 2013 updated 

attainment demonstration. The updated attainment demonstration allows fewer 

emissions in 2018.

The 2013 Update addresses several CAA planning requirements. The revised summer 

planning emission inventories account for the implementation of recently adopted 

control measures, the effects of the recession, and updated transportation activity 

projections provided by the Sacramento Area Organization of Governments (SACOG). 

The 2013 Update demonstrates attainment of the 8-hour ozone standard, by 2018, 

using these updated inventories. An updated reasonable further progress (RFP) 

ES-1
analysis uses the updated inventories. The updated, locally approved transportation 

conformity budgets incorporate the updated emission estimates and include conformity 

safety margins. An ozone vehicle miles traveled (VMT) offset demonstration included in 

this update is based on guidance issued by U.S. EPA in August, 2012. The update also 

includes an updated reasonable available control measure (RACM) analysis.

Staff Recommendation

Staff recommends that the Board adopt the Proposed Revisions to the “Sacramento 

Regional 8-Hour Ozone Attainment and Reasonable Further Progress Plan 2013 SIP 

Revisions” as a revision to California’s SIP.

ES-2
1. Implementing the 2009 Plan

The 2013 Update is a revision to the 2009 Plan. The 2009 Plan was adopted by the five 

districts that make up the Sacramento Nonattainment Area: the Sacramento 

Metropolitan Air Quality Management District (SMAQMD); the El Dorado Air Quality 

Management District (EDAQMD); the Feather River Air Quality Management District 

(FRAQMD); the Yolo-Solano Air Quality Management District (YSAQMD); and the 

Placer County Air Pollution Control District (PCAPCD). ARB adopted the 2009 Plan as 

a revision to the SIP and submitted it to U.S. EPA. The 2009 Plan included a request 

for the Sacramento Nonattainment Area to be reclassified from “Serious” to 

“Severe-15.” U.S. EPA finalized the reclassification, changing the attainment deadline 

from June 2013 to June 2019. However, U.S. EPA has not yet acted on the overall 

attainment demonstration, pending submittal of updated information. The 2013 Update 

incorporates the information necessary for U.S. EPA approval.

2007 State Strategy Implementation

The 2009 Plan relied in part on control measures and control measure commitments 

identified in ARB’s 2007 State Strategy for California’s SIP. ARB has adopted all but 

one of the 2007 State Strategy measures included in the 2009 Plan. Table A1 in 

Appendix A lists ARB measures adopted since 2007 and sent to U.S. EPA as revisions 

to the SIP, as requests for waivers under Clean Air Act (CAA) section 209(b), or for 

authorizations under CAA section 209(e)(2). 

The Sacramento region’s ozone attainment strategy relies on reductions of both oxides 

of nitrogen (NOx) and volatile organic compounds (VOC) to meet the 8-hour ozone 

standards. Because mobile sources are the largest contributors to ozone-forming 

emissions, reducing emissions from passenger vehicles, trucks, and a variety of 

off-road engines is key to attaining the ozone standards. In developing the Sacramento 

Area SIP for meeting the 8-hour standard by 2018, the biggest challenge was cleaning 

up the existing fleets of diesel engines. This challenge was addressed by the adoption 

of ARB’s in-use fleet rules for on-road trucks and off-road equipment.

Tables 1 and 2 shows the impact of adopted State measures on projected 2018 

emissions in the Sacramento Nonattainment Area. As a result of these adopted 

controls, 2018 emissions are now projected to be at or below the level needed to 

demonstrate attainment, as discussed in Section 2. This section describes the adopted 

measures and programs that are providing these reductions.

1
Table 1: Analysis of ARB's Implemented Regulations using

Calendar Year 2018 NOx Summer Season Emissions (tpd)

Statewide SIP Measures

2009 SIP Summary Current 

Estimate

2018 

Baseline

Expected 

Reductions

Remaining 

Emissions

Remaining 

Emissions

Passenger Vehicles 22.2 1.7 20.5 16.7

Smog Check Improvements (BAR)

22.2

1.4

Expanded Vehicle Retirement 0.3 20.5 16.7

Modifications to Reformulated Gasoline Program 0.0

Heavy-Duty Trucks 22.4 9.5 12.9 12.6

Cleaner In-Use Heavy-Duty Trucks 22.4 9.5 12.9 12.6

Goods Movement Sources 10.3 2.1 8.2 7.0

Accelerated Intro. Of Cleaner Line-Haul Locomotives 9.4 1.9 7.5 6.2

Clean Up Existing Harbor Craft 0.9 0.2 0.7 0.9

Off-Road Equipment 13.4 1.9 11.5 7.0

Cleaner In-Use Off-Road Equipment (over 25hp) 13.4 1.9 11.5 7.0

Other Off-road Sources 6.1 0.3 5.8 2.4

New Emission Standards for Recreational Boats 5.9 0.3 5.6 2.3

Expanded Off-Road Rec. Vehicle Emission Standards 0.1 0.0 0.1 0.1

Additional Evaporative Emission Standards -- -- -- --

Areawide Sources 0.0 0.0 0.0 0.0

Consumer Products Program 0.0 0.0 0.0 0.0

2018 NOx Totals

State SIP Measure Sources1 74 16 59 46

All Other State/Federal Source Categories2 9 -- 9 13

District Source Categories 17 2 15 12

Total Inventory 101 18 83 71

Emission Reduction Credits2 3 -- 3 3

Motor Vehicle Emission Budget Safety Margin -- -- -- 3

Total Inventory for the 2013 Update 104 18 86 77

1 State SIP Measure Sources un-truncated. 2013 Plan uses truncated numbers.

2 For the purposes of this table, ERCs are shown separately.

2
Table 2: Analysis of ARB's Implemented Regulations using Calendar Year 2018 VOC 

Summer Season Emissions (tpd)

Statewide SIP Measures

2009 SIP Summary Current 

Estimate

2018 

Baseline

Expected 

Reductions

Remaining 

Emissions

Remaining 

Emissions

Passenger Vehicles 24.9 2.6 22.3 16.3

Smog Check Improvements (BAR)

24.9

1.3

Expanded Vehicle Retirement 0.2 22.3 16.3

Modifications to Reformulated Gasoline Program 1.1

Heavy-Duty Trucks 1.9 0.8 1.1 0.8

Cleaner In-Use Heavy-Duty Trucks 1.9 0.8 1.1 0.8

Goods Movement Sources 0.7 0.1 0.6 0.4

Accelerated Intro. Of Cleaner Line-Haul Locomotives 0.6 0.1 0.5 0.3

Clean Up Existing Harbor Craft 0.1 0.0 0.1 0.1

Off-Road Equipment 7.5 0.4 7.1 6.5

Cleaner In-Use Off-Road Equipment (over 25hp) 7.5 0.4 7.1 6.5

Other Off-road Sources 22.8 6.1 16.7 14.4

New Emission Standards for Recreational Boats

22.8

3.0

Expanded Off-Road Rec. Vehicle Emission Standards 2.7 16.7 14.4

Additional Evaporative Emission Standards 0.4

Areawide Sources 15.1 1.9 13.2 13.2

Consumer Products Program 15.1 1.9 13.2 13.2

2018 VOC Totals

State SIP Measure Sources1 73 12 61 52

All Other State/Federal Source Categories 5 -- 5 3

District Source Categories 40 3 36 39

Total Inventory 117 15 102 94

Emission Reduction Credits2 4 -- 4 4

Motor Vehicle Emission Budget Safety Margin -- -- -- 1

Total Inventory for the 2013 Update 121 15 106 99

1 State SIP Measure Sources un-truncated. 2013 Plan uses truncated numbers.

2 For the purposes of this table, ERCs are shown separately.

3
Clean New and In-Use Heavy-Duty Trucks 

Increasingly stringent standards for new trucks are a central element of ARB’s emission 

reduction strategy. New heavy-duty trucks sold since 2010 emit 98 percent less NOx 

and fine particulates (PM2.5) than new trucks sold in 1986. However, older, 

higher-emitting trucks with long service lives can stay on the road for many years. 

Because of this, emissions from existing “in-use” trucks must also be reduced in order 

to meet near-term air quality standards.

To address this, ARB developed the Cleaner In-Use Heavy-Duty Truck Regulation. 

This measure leverages the benefits provided by new truck emission standards by 

accelerating introduction of the cleanest trucks. The “Truck and Bus Regulation” was 

adopted in December 2008, and amended in December 2010 to account for the 

reduced emissions resulting from the economic effects of the recession. The rule 

represents a multi-year effort to retrofit or replace engines in the older part of the fleet 

with the cleanest technology available. 

Cleaner In-Use Off-Road Equipment

ARB has also adopted increasingly stringent standards for engines used in new off-road 

diesel equipment. As a result of these standards, new construction, mining, industrial 

and oil drilling equipment will become progressively cleaner. However, large diesel 

off-road equipment typically remains in use for many years, if not decades. As with 

heavy-duty trucks, this long life means that newer, lower-emitting engines would be 

introduced into fleets relatively slowly, making the emission reductions and associated 

health benefits from these cleaner engines would also be fairly slow to materialize.

To address this, the State Strategy for California’s 2007 SIP included the Cleaner In-use 

Off-road Equipment Regulation, the “Off-Road Regulation.” First approved in 2007, the 

Off-Road Regulation was amended in 2010 in light of the impacts of the economic 

recession. The off-road equipment affected by this regulation is used in construction, 

manufacturing, the rental industry, road maintenance, airport ground support, and 

landscaping. In December 2011, the Off-Road Regulation was modified to include 

on-road trucks with two diesel engines.

Advanced Clean Cars

ARB’s Advanced Clean Cars (ACC) Program, approved in January 2012, is a set of 

pioneering regulations that address both ambient air quality needs and climate change. 

The ACC program combines the control of smog, soot causing pollutants, and 

greenhouse gas emissions into a single coordinated set of requirements for model 

years 2015 through 2025. The program assures the development of environmentally 

superior cars that will continue to deliver the performance, utility, and safety vehicle 

owners have come to expect. 

The ACC Program will produce increasing benefits over time as new cleaner cars enter 

the fleet, displacing older and dirtier vehicles. Increasingly stringent fleet average 

composite emission standards for model years 2015 to 2025 ensure that the program 

4
will continue to provide benefits, beyond the Sacramento Nonattainment Area’s 2018 

attainment deadline, as vehicles meeting the new standards replace older, 

higher-emitting vehicles.

Expanded Passenger Vehicle Retirement

Voluntary accelerated vehicle retirement or “car scrap” programs give vehicle owners 

monetary incentives to retire older, more polluting vehicles. California’s updated 

voluntary vehicle retirement program is administered by the Bureau of Automotive 

Repair (BAR) and provides $1,000 per vehicle and $1,500 for low-income consumers 

for unwanted vehicles that have failed their last Smog Check test and meet eligibility 

guidelines.

Improvements and Enhancements to California’s Smog Check Program

The following requirements were added to improve and enhance the Smog Check 

Program, and to include additional passenger vehicle categories:

• Low pressure evaporative test;

• More stringent pass/fail cutpoints;

• Visible smoke test; and

• Inspection of light- and medium-duty diesel vehicles.

AB 2289, adopted in October 2010, restructured California’s Smog Check Program by 

streamlining and strengthening inspections, increasing penalties for technicians that 

conduct improper Smog Checks, and reducing costs to motorists. This new law takes 

advantage of diagnostic software installed on all vehicles manufactured since 2000 and 

directs vehicles without this equipment to high-performing stations to ensure compliance

with current emission standards.

Accelerated Introduction of Cleaner Line-Haul Locomotives 

California leads the nation with the most extensive efforts to reduce locomotive and rail 

yard emissions. The Union Pacific (UP) rail yard located in Roseville has benefitted 

from numerous programs targeting NOx and PM2.5 emissions. ARB utilized 

Proposition 1B funding for 15 Tier 2 “regional” line haul locomotives. UP also operates 

six ultra-low emitting genset switch locomotives within the Roseville rail yards. The 

UP 9900, an experimental Tier 3+ locomotive (Tier 4 PM, and Tier 3+ NOx), has been 

assigned to UP Roseville and operates primarily in Northern California. 

Consumer Products

Under State law, ARB has regulatory responsibility for reducing VOC emissions from 

consumer products. ARB approved amendments to the Consumer Products regulations 

that established lower VOC emission limits for a wide variety of products, including 

5
household cleaning and degreasing products, home and garden pesticides, aerosol 

paints, personal care products, and automotive maintenance products.

Local Strategy Implementation

Local air districts are responsible for controlling emissions from most stationary and 

areawide sources. Such sources include factories, power plants, gas stations, dry 

cleaners, residential water heaters, and managed burning. The five districts that make 

up the Sacramento Nonattainment Area have adopted a variety of control measures to 

control emissions from these sources. The local plan element includes implemented 

control measures and commitments to develop and adopt new measures. These 

measures target architectural coatings, automotive refinishing products, degreasing and 

solvent cleaning products, metal parts coatings, natural gas processing, portable 

asphalt dryers, water heaters and boilers, and stationary internal combustion engines. 

These district measures are expected to provide a total of 2.8 tons per day additional 

VOC reductions and 1.1 tons per day additional NOx reductions.

In coordination with local metropolitan planning organizations (MPO), the local air 

districts have also adopted several transportation control measures (TCM). 

Sacramento Emergency Clean Air & Transportation grant program (SECAT) is a joint 

project between SMAQMD and SACOG that provides grant funds to replace on-road 

heavy-duty diesel vehicles that have 1998–2006 model year engines with cleaner 

emission vehicles.

U.S. EPA has not yet acted on the 2009 Plan attainment strategy. In 2011, the local 

districts withdrew some of the local strategy commitments submitted as part of the 2009 

Plan in light of the new information and cost estimates. This submittal contains the 

most recently adopted local strategy for approval by the U.S. EPA.

The emission inventories used in this update were developed in part for use in the 

Northern California regional air quality model. Because emission reduction credits are 

modeled as actual emissions for attainment demonstration purposes, the emission 

reduction credits that have been banked with the Sacramento Nonattainment Area

districts were allocated across the stationary and area-wide source categories in the 

modeling inventory. For the purpose of the attainment, contingency and reasonable 

further progress demonstrations in this update, the credits are subtracted from the 

inventory outputs for those categories and shown as separate line items as they were in 

the original plan.

6
2. Attainment Demonstration

The 2009 Plan used photochemical modeling to demonstrate that the proposed 

emission reduction strategy would allow the Sacramento Nonattainment Area to attain 

the 1997 8-hour ozone standard by 2018, the attainment deadline for severe 

nonattainment areas. The 2013 Update uses more current inventories with significantly 

different estimates of both baseline and attainment year emission. An analysis of the 

attainment demonstration using the revised inventories confirms the original finding that 

the 2013 Update demonstrates attainment by 2018, and shows that the area has made 

significant progress towards meeting that goal because of adopted control. This section 

also addresses U.S. EPA requirements for ensuring that the plan will result in 

attainment throughout the nonattainment area.

SIP Emissions Targets

An attainment demonstration plan identifies emission targets, or “carrying capacities,” 

that represent the maximum emission levels that the nonattainment area can 

accommodate while attaining the standard. Air quality modeling is used to determine 

these emission targets. The modeling conducted for the 2009 Plan used the base and 

future year emission inventories that were available when the modeling for that plan 

started. The 2009 Plan showed that that the 2018 emissions targets would be met 

through a combination of adopted measures and new SIP measures. 

The 2013 Update confirms that the Sacramento Nonattainment Area will attain the 1997 

8-hour ozone standard by 2018.

This update uses new emission inventories as described in Section 3. Developing new 

SIP modeling that utilizes these new inventories in order to revisit the adopted 

attainment demonstration would be a multi-year process. Instead, the existing modeling 

results were updated using an analytical approach, described in this section, to 

demonstrate that the emission reductions achieved by the 2009 Plan, as updated in the 

2013 SIP Revision, will result in attainment of the 8-hour ozone standard by 2018 

deadline.

Updated Attainment Demonstration

The 2009 Plan used a photochemical air quality modeling to identify attainment goals. 

The air quality modeling, described in Appendix B of the 2009 Plan, used 2002 as the 

base year. It projected air quality in 2018 using forecasted emissions that include 

activity growth factors and the benefits of adopted controls, but no new SIP measures. 

In the Sacramento Nonattainment Area this projected ozone level was above the 8-hour 

ozone standard, indicating additional emission reductions were needed, beyond those 

that would result from the existing control program. To provide these additional 

reductions, the 2009 SIP included commitments for future actions by ARB and the air 

districts. 

7
The revised inventories used in the 2013 Update, which include new growth forecasts 

and the reductions from actions taken since 2009, project emissions in 2018 that are 

below those needed for attainment. However the revised inventories changed both the 

base year and attainment year emission estimates. To be conservative, the 2013 

Update attainment analysis re-calculates the attainment target by applying the

percentage of NOx and VOC emission reductions needed in the 2009 Plan to the 

updated inventory, resulting in new NOx and VOC emission targets, expressed as tons 

per day. Those targets are then compared to the updated inventory, which includes the 

effects of rules adopted to date, to assess current progress toward attainment of the 

standard. The analysis is summarized in Table 3 and detailed in Appendix B. It shows 

that adopted controls will provide the new NOx reductions needed, from 2002 levels, to 

attain the standard. The analysis shows that in 2018, existing rules will provide 108 

percent of the needed VOC emission reductions. The 2013 Update also identifies 

additional control measures under development that will provide future NOx reductions

beyond those needed for attainment. 

The air quality modeling prepared for the 2009 Plan and described in Appendix B of that 

plan supports the conclusion that adopted and committed controls will result in 

attainment by 2018. The modeling also suggested that as overall NOx emissions

decrease, each new ton of NOx reductions will have an incrementally greater ozone 

benefit and cause ozone concentrations to decrease more rapidly, also supporting this 

revised attainment demonstration.

U.S. EPA requires that attainment demonstrations submitted as part of a SIP include an 

unmonitored area analysis. This analysis is intended to identify areas without routine air 

monitoring sites where future year design values may be greater than the standard. 

The unmonitored area analysis prepared for the 2013 update indicates that there will be 

no areas in 2018 where ozone concentrations exceed those predicted for the monitoring 

sites. A detailed discussion of the Sacramento Nonattainment Area unmonitored area 

analysis is included in Appendix F.

8
Table 3: Attainment Demonstration Summary (tpd)

2009 Attainment and RFP Plan Inventory

(CEFS 1.061) NOx VOC

A. 2002 Total Emissions 196 160

B. SIP Attainment Target 91 117

C. Attainment Emission Reductions Required from 

2002 Baseline in tons/day [A-B] 105 43

D. Attainment Emission Reductions Required from 

2002 Baseline in % [C/A] 54% 27%

2013 Inventory (adjusted CEPAM 20122) NOx VOC

E. 2002 Updated Emissions Inventory 165 147

F. Attainment Reductions Required in % 54% 27%

G. Attainment Emission Reduction in tons/day [E*F] 88 40

H. Updated Attainment Demonstration Target [E-G] 77 107

I. 2018 Emissions with Adopted Rules 77 99

Updated Inventory (adjusted CEPAM 20122) NOx VOC

J. Attainment Demonstration in % [H/I] 100% 109%

1 California Emission Forecasting System

2 California Emissions Projection Analysis Model

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10
3. Other Clean Air Act Planning Requirements 

This section provides an overview of the revisions reflected in the emission inventories

used in the 2013 Update. Several CAA requirements rely on the emission inventories 

and must be updated to reflect the revised inventories; this section also summarizes 

revisions to the reasonable further progress demonstration, transportation control 

conformity budgets, and a Reasonably Available Control Measure (RACM) analysis. In 

addition, a 2011 court ruling necessitated the adoption of a revised Vehicle Miles 

Traveled (VMT) offset demonstration that is also summarized in this section.

Emission Inventory

An emissions inventory is a critical tool used to develop air pollution control strategies 

and to evaluate progress in implementing adopted strategies. The emissions inventory 

is a systematic listing of the sources of air pollutants along with the amount of pollutants 

emitted from each source or category of sources over a given time period. The 

emission inventories used in the ozone plan are summer season inventories that reflect

the activity levels and conditions present when higher ozone levels occur in Sacramento 

Nonattainment Area.

The air districts within the Sacramento Nonattainment Area initially adopted the 2009

Plan in February 2009. The inventories used in the 2009 Plan reflected the most 

up-to-date and accurate estimates of emission available at that time.

Since the 2009 Plan was adopted, both ARB and the Sacramento Nonattainment Area

districts have continued to evaluate and update emission estimates for source 

categories under their respective authority. Several significant changes are reflected in 

the inventories used in this update:

• The inventories reflect effects of new local, State and federal regulations.

• The inventories reflect new information about activity and emission levels gained 

as ARB developed its mobile source regulations.

• Changes in growth and activity factors for some sectors reflect the impacts of the 

recession.

• The inventories use the most current SACOG transportation activity forecasts.

• The inventories reflect other improvements identified by the Sacramento 

Nonattainment Area districts.

The 2013 Update emission inventory is derived from California Emissions Projection 

Analysis Model (CEPAM). CEPAM 2012 uses a 2005 baseline inventory; the inventory 

was calibrated to 2005 emissions and activity levels, and inventories for other years are 

back-cast or forecast from that base inventory. The 2009 Plan used a 2002 base-year 

inventory.

CEPAM 2013 incorporates the results of a thorough review of the off-road mobile 

source inventory methodology, and updated many key factors used in estimating 

11
emissions from off-road vehicles. This included new population and activity data 

reported to ARB, as well as new published studies and other data that evaluated 

emissions from off-road vehicles. Staff also evaluated new data that showed that the 

previous inventory overestimated certain off-road mobile source emissions. The 

resulting emission estimates show a 33 percent reduction in off-road baseline NOx 

emissions and a 17 percent reduction in off-road baseline VOC emissions as compared 

to the inventory used in the 2009 Plan.

The Sacramento Nonattainment Area districts’ improvements include the use of the 

most recent transportation activity data provided by SACOG and updates to several 

local source categories subject to recent local rulemaking. SMAQMD identified several 

new facilities whose emissions are included in the updated inventory. The updated 

inventories also account for a transportation safety margin that provides room for 

unanticipated growth in on-road emissions.

Appendix C provides a detailed review of the emission inventory used in this update. In 

aggregate, the updated emission estimates show a 16 percent reduction in baseline 

NOx emissions and 9 percent reduction in regional baseline VOC emissions for 2002.

The emission reduction commitments in the 2007 State Strategy are based on 

estimates of reductions achieved from individual new measures. However, it is 

important to note that the overall commitment is to provide for attainment of the federal 

standards through aggregate emission reductions resulting from the implementation of 

the State Strategy. If an individual measure does not result in the expected emission 

reduction, the State still commits to attainment through other measures emission 

reductions. Likewise, if an individual measure results in greater than expected 

reductions, those additional reductions may be counted towards the State’s aggregate 

emission reduction commitment.

Emission Reduction Credits

The inventory used in this update was developed in part for use in the Northern 

California regional air quality model. Because banked emission reduction credits are 

modeled as actual emissions for attainment demonstration purposes, the emission 

reduction credits were allocated across the stationary and area-wide source categories 

for the modeling inventory. For the purpose of the attainment, contingency and 

reasonable further progress demonstrations in this update, the credits are subtracted 

from the inventory outputs for those categories and shown as separate line items as 

they were in the original plan

Reasonable Further Progress Demonstration

To ensure that nonattainment areas make consistent progress towards attainment of 

the ozone standard, SIPs for these areas are required to show a three percent per year 

reduction in both VOC and NOx emissions, averaged over a three year period, up to the 

attainment year. The last milestone year for the Sacramento Nonattainment Area’s 

reasonable further progress (RFP) demonstration is 2014. This milestone year is 12

12
years after the finalized amendment of the 1997 8-Hour Ozone standard, so a 36%

reduction in VOC emissions is needed to demonstrate RFP.

The Sacramento Nonattainment Area is forecasting a shortfall of 9.9% VOC emission 

reductions in 2014. Section 182 (c)(2)(C) of the CAA provides the ability to substitute 

surplus NOx emission reductions to mitigate any VOC emission reduction shortfalls.

The RFP analysis shows sufficient NOx emission reductions to accommodate the VOC 

shortfall, and to provide a 3% contingency in each milestone year as required under 

sections 172(c)(9) and 182(c)(9) of the CAA.

The complete RFP analysis is provided in Appendix D.

Transportation Conformity Budgets 

Under section 176(c) of the Act, transportation projects must be fully consistent with the 

SIP to receive federal funding or approval. U.S. EPA’s transportation conformity rule 

details requirements for establishing motor vehicle emission budgets in SIPs for the 

purpose of addressing whether transportation plans and programs conform to the SIP.

The 2013 Update establishes on-road motor vehicle emission budgets for the 8-hour 

ozone standard. The on-road mobile inventories and the transportation conformity 

budgets are estimated using California’s CEPAM2012 and EMFAC2011 on-road mobile 

emissions model. EMFAC2011 was approved by U.S. EPA on March 6, 2013. The 

latest activity from SACOG was used as inputs into the EMFAC 2011 model for this 

inventory. In Appendix C, Tables C1 and C2 shows all adjustments made to the default 

CEPAM2012 output used to develop the transportation conformity budgets.

Appendix E provides Sacramento’s motor vehicle emission budgets for the upcoming 

milestone years of 2014, 2017, and 2018. The motor vehicle emission budgets are 

generated from EMFAC2011 using SACOG’s 2013 MTIP activity data as described 

above.

A locally adopted safety margin is included in each of the updated conformity budgets to 

allow for unanticipated growth in on-road emissions.

Reasonably Available Control Measures Analysis

The CAA requires SIPs to provide for the implementation of all reasonable available 

control measures (RACM) as expeditiously as practicable, including at minimum 

reasonably available control technology (RACT). U.S. EPA interprets RACM to be

those measures that are technologically and economically feasible, that when 

considered in aggregate would advance the attainment date by at least one year.

The District RACM/RACT demonstration includes a comparison of stationary source 

measures the District has implemented, or plans to implement, with measures 

implemented by other agencies within and outside of the State. For the majority of 

13
stationary and area source categories, the District rules are the most stringent in 

California. 

Based U.S. EPA guidance, the District concluded the 2013 Update meets the 

RACM/RACT requirements of the CAA. These requirements include a demonstration 

that no additional feasible measures could be identified that could, in aggregate, 

accelerate attainment by one year. The complete RACM and RACT for stationary and 

area-wide sources assessments are provided in Appendix H of the District’s 2013 

Update. The RACM analysis for TCM’s is provided in Appendix A-2 of the District’s 

2013 Update.

California’s comprehensive mobile source program continues to be RACM as it expands 

and further reduces emissions. Given the significant emission reductions needed for 

attainment in California, ARB has adopted the most stringent control measures 

nationwide for on-road and off-road mobile sources and the fuels that power 

them. These measures provide a significant portion of emission reductions needed for 

the Sacramento Nonattainment Area to attain the 8-hour ozone standard.

Ozone VMT Offset Demonstration 

Section 182(d)(1)(A) of the Act requires that SIPs for areas classified as Severe and 

above include a demonstration that “identifies specific enforceable transportation control 

strategies and transportation control measures to offset any growth in emissions from 

growth in such area....” The 2009 Plan demonstrated this requirement was met, using 

a methodology that had been used in other SIPs approved by U.S. EPA. However, this 

methodology was subsequently invalidated in a 2011 ruling by the Ninth Circuit Court of 

Appeals. The 2013 Update includes a “Vehicle Miles Travelled Offset Demonstration” 

that complies with guidance U.S. EPA published in August 2012 in response to the 

court’s ruling. The 2013 Update demonstrates that emission increases due to VMT 

growth are appropriately offset by transportation control strategies and transportation 

control measures using two alternative methodologies.

Staff Recommendations

ARB staff recommends that the Board approve the 2013 Revisions to the Sacramento 

Regional 8-Hour Ozone Attainment and Reasonable Further Progress Plan as a 

revision to the California SIP. Staff further recommends that the Board direct the 

Executive Officer to submit the 2013 Revisions to the Sacramento Regional 8-Hour 

Ozone Attainment and Reasonable Further Progress Plan to U.S. EPA as a revision to 

the California SIP.

14
Appendices

Table of Contents

Appendix A ARB Rulemaking...................................................................................A-1

Table A1: CARB Measures Adopted ........................................................................A-1

Appendix B Attainment Demonstration Analysis.......................................................B-1

Table B1: Synopsis of Attainment Demonstration in the 2009 Attainment and RFP 

Plan (tpd)..................................................................................................................B-3

Table B2. 2013 Updated Attainment Demonstration Target (tpd).............................B-3

Table B3. 2013 Updated Attainment Demonstration (tpd) ........................................B-4

Table B4: Attainment Contingency Measures Reductions (tpd) ...............................B-4

Table B5: Additional Measures(tpd)..........................................................................B-4

Appendix C Emission Inventory Update .................................................................. C-1

Table C1: Summer Planning Emissions Inventory for Nitrogen Oxides (NOx) in tons

per day Sacramento Nonattainment Area................................................................ C-2

Table C2: Summer Planning Emissions Inventory for Volatile Organic Compounds 

(VOC) in tons per day Sacramento Nonattainment Area......................................... C-4

Table C3: Emissions Inventory Adjustments for Nitrogen Oxides (NOx) in tons per 

day Sacramento Nonattainment Area...................................................................... C-6

Table C4: Emissions Inventory Adjustments for Volatile Organic Compounds (VOC) in 

tons per day Sacramento Nonattainment Area........................................................ C-7

Table C5: Emission Reduction Credits Added to the Emission Inventory Forecasts C8

Appendix D Reasonable Further Progress .............................................................. D-1

Table D1: Sacramento Nonattainment Area Reasonable Further Progress 

Demonstration ......................................................................................................... D-1
Appendix E Transportation Conformity Baseline Adjustments..................................E-1

Table E1: Sacramento Nonattainment Area NOx Motor Vehicle Baseline Emissions

Adjustments in tons per day .....................................................................................E-1

Table E2: Sacramento Nonattainment Area VOC Motor Vehicle Baseline Emissions 

Adjustments in tons per day .....................................................................................E-1

Appendix F Unmonitored Area Analysis...................................................................F-1
Appendix A

ARB Rulemaking

Table A1: CARB Measures Adopted

Measure Date of 

Adoption

Date Sent to 

U.S. EPA

Modifications to Reformulated Gasoline Jun. 14, 2007 Feb. 03, 2009

Vapor Recovery for Above-Ground Storage 

Tanks Jun. 21, 2007 Jun. 12, 2008

Clean Up Existing Harbor Craft Nov. 15, 2007 Apr. 12, 2010

Ship Auxiliary Engine Cold Ironing and Clean 

Technology Dec. 06, 2007 Aug. 02, 2010

Consumer Products Program

--2008 amendment Jun. 26, 2008 Feb. 16, 2010

--2009 amendment Sep. 24, 2009 Jan. 28, 2011

Additional Evaporative Emission Standards Sep. 25, 2008 May 02, 2011

Portable Outboard Marine Tanks Sep. 25, 2008 May 02, 2011

Smog Check Improvements Aug. 31, 2009 Oct. 28, 2009

Pesticides Element Oct. 12, 2009 Aug. 02, 2011

Cleaner In-Use Heavy-Duty Trucks Dec. 16, 2010 Sep. 21, 2011

Cleaner In-Use Off-Road Equipment Dec. 17, 2010 Sep. 21, 2011

Port Truck Modernization Dec. 17, 2010 Sep. 21, 2011

Cleaner Main Ship Engines and Fuel for OceanGoing Vessels Jun. 23, 2011 Sep. 21, 2011

Offroad Recreational Vehicles1 Jul. 25, 2013 Pending

1 Benefits are not yet incorporated in the Emission Inventory

A-1
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A-2
Appendix B

Attainment Demonstration Analysis

This Appendix provides the analytic procedures used, in lieu of modeling, to assess the 

Sacramento Nonattainment Area attainment demonstration submitted as part of the 

original 2009 Plan in light of the revised emission inventories submitted as part of the 

2013 Update. Table 3 presents the updated attainment demonstration. The emission 

reductions in the updated attainment demonstration result from adopted measures that 

have been submitted to the U.S. EPA. The 2013 Update also identifies additional 

control measures under development that will provide further reductions beyond those 

needed for attainment.

The inventories used in this update are derived from ARB’s CEPAM 2012, with mobile 

source emissions estimated using ARB’s EMFAC 2011 model and activity data provided 

by SACOG on January 23, 2013. However, ARB and the local districts identified 

additional refinements needed to bring these baseline inventories up to date for the 

purposes of assessing the attainment demonstration and progress towards attainment. 

The CEPAM 2012 inventory and baseline adjustments are summarized in Appendix C. 

Synopsis of Attainment Demonstration in the 2009 Attainment and RFP Plan –

Table B1

Table B1 presents the emission inventory in the 2009 Plan to calculate the percent 

reductions required from the 2002 Baseline to attain the ozone standard.

2013 Updated Attainment Demonstration Target – Table B2

Table B2 calculates the updated attainment demonstration target by applying the 

percent reductions required for attainment determined in Table B1 to the 2013 Update’s 

emission inventory, following the procedures described in Chapter 2

2013 Updated Attainment Demonstration – Table B3

The 2013 Update’s 2018 projected emission inventories are compared to the updated 

attainment demonstration target in Table B3. This demonstrates that adopted 

measures provide the emission reductions necessary to demonstrate attainment.

Attainment Contingency Measures Reductions – Table B4

Table B4 compares the updated 2019 emission inventory to the attainment target 

calculated in Table B2. Table B4 demonstrates that in aggregate already adopted 

measures reflected in the 2013 Update provide for at least three percent emission 

reductions in 2019, beyond those needed for attainment, as required by the Act’s 

section 182(c)(9) contingency requirement. Please refer to Appendix C in the 

2013 Update for additional details.

B-1
Additional Measures – Table B5

Table B5 lists State and local control measure commitments identified in the 2009 Plan 

that are under development and therefore are not yet reflected in the updated inventory, 

and the associated expected emission reductions. These additional measures are not 

necessary for attainment, reasonable further progress, or contingency, but will provide 

continuing emission reductions.

B-2
Table B1: Synopsis of Attainment Demonstration 

in the 2009 Attainment and RFP Plan (tpd)

2009 Attainment and RFP Plan Inventory (CFS 1.06) NOx VOC

A. 2002 Total Emissions1 196 160

B. 2018 Total Emissions1 101 117

C. Emission Reduction Credits2 3 4

D. Adjusted 2018 Total Emissions [B+C] 104 121

Baseline Attainment Emission Target NOx VOC

E. Attainment Emission Reductions in 2018 in %3 12.5% 3.3%

F. Attainment Emission Reduction in tons/day [D*E] 13 4

G. SIP Attainment Demonstration Target [D-F] 91 117

Baseline Attainment Ratio NOx VOC

H. Attainment Emission Reductions Required from 

2002 Baseline in tons/day [A-G] 105 43

I. Percent Emission Reductions Required from 2002 

Baseline for Attainment [H/A] 54% 27%

1 2009 Plan - Tables 5-2 and 5-3.

2 2009 Plan - Tables A6-1 and A6-2.

3 2009 Plan - Appendix B.

Table B2. 2013 Updated Attainment Demonstration Target (tpd)

Revised Inventory (adjusted CEPAM 2012) NOx VOC

A. 2002 Updated Emissions Inventory1 165 147

B. Reductions Required for Attainment in %2 54% 27%

C. Attainment Emission Reduction in tons/day [A*B] 88 40

D. Adjusted SIP Emission Target [A-C] 77 107

1 Table C1 and Table C2.

2 Table B1.

B-3
Table B3. 2013 Updated Attainment Demonstration (tpd)

Revised Inventory (adjusted CEPAM 2012) NOx VOC

A. Adjusted 2018 Emission Inventory1 77 99

B. Updated Attainment Demonstration Target2 77 107

C. Updated Attainment Demonstration in % [B/A] 100% 109%

1 Table C1 and C2.

2 Table B2.

Table B4: Attainment Contingency Measures Reductions (tpd)

Revised Inventory (adjusted CEPAM 2012) NOx VOC

A. Updated Attainment Demonstration Target1 77 107

B. Adjusted 2019 Emissions2 74 100

2019 Total Reductions (tpd) NOx VOC

C. 2019 Reductions From Emission Target [A-B] 2 7

D. Percent Reduction from SIP Emission Target [C/A] 3% 7%

1 Table B2.

2 Table C1 and Table C2.

Table B5: Additional Measures(tpd)1

Statewide NOx VOC

A. Statewide Measure 0.3 3

New Emission Standards for Recreational Boats 0.3 3.0

Local Non-Regulatory Measures NOx VOC

B. Total Local Non-Regulatory Measures 0.6 0.1

Regional Mobile Incentive Program - Onroad 0.5 0.02

Regional Mobile Incentive Program - Offroad 0.0 0.02

Spare the Air Program 0.02 0.1

SMAQMD NOx VOC

C. Total SMAQMD Measures 0.0 1.1

442 - Architectural Coatings 0.0 0.9

459 - Automotive Refinishing 0.0 0.1

461 - Natural Gas Production and Processing 0.0 0.1

B-4
EDCAQMD NOx VOC

D. Total EDCAQMD Measures 0.02 0.2

215 - Architectural Coatings 0.0 0.2

239 - Large Water Heaters and Small Boilers 0.02 0.0

FRAQMD NOx VOC

E. Total FRAQMD Measures 0.02 0.02

3.15 - Architectural Coatings 0.0 0.02

3.19 - Automotive Refinishing 0.0 0.02

3.14 - Solvent Degreasing 0.0 0.02

3.22 - Stationary Internal Combustion Engines

(Non-Agricultural) 0.02 0.0

3.23 - Large Water heaters and Small Boilers 0.02 0.0

PCAPCD NOx VOC

F. Total PCAPCD Measures 0.02 0.3

218 - Architectural Coatings 0.0 0.2

234 - Automotive Refinishing 0.0 0.02

CM2 - Large Water Heaters and Small Boilers 0.02 0.0

CM3 - Miscellaneous Metal Parts and Products 0.0 0.02

YSAQMD NOx VOC

G. Total YSAQMD Measures 0.5 1.0

2.14 - Architectural Coatings 0.0 0.2

2.26 - Automotive Refinishing 0.0 0.1

2.24/2.31 - General Surface Preparation/Cleanup 

and Degreasing 0.0 0.8

2.29 - Graphic Arts 0.03 0.03

2.27 - Boilers, Steam Generators, and Process 

Heaters 0.3 0.0

2.37 - Large Water Heaters and Small Boilers 0.2 0.0

1 These additional measures are under development. The emission reductions associated 

with these measures go beyond those needed for the attainment demonstration.

2 Emissions <0.05 tpd.

3 No current estimate on emission reduction.

B-5
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B-6
Appendix C

Emission Inventory Update

Revised Emission Inventory

This appendix provides the unadjusted inventory that is derived from CEPAM2012. 

Tables C1 and C2 summarize the summer planning emission inventories for the 

Sacramento 8-Hour Federal Nonattainment Area (Sacramento Nonattainment Area).

This Appendix provides more detail about the emission inventories used in the 2013 

Update, including a summary of the baseline inventory and subsequent refinements.

Baseline Inventory

CEPAM2012 is used for the baseline inventory for Stationary, Area-Wide and Off-Road 

Mobile sources. EMFAC2011 was used in January 2013, using the activity data 

provided by SACOG, to provide the On-Road Mobile sources.

Emission Inventory Adjustments

The emission inventories in C1 and C2 are adjusted to reflect updated stationary 

sources, new transportation activity data provided from SACOG, and the inclusion of the 

transportation conformity safety margin. These adjustments are detailed and summated 

in Tables C3 and C4.

Emission Reduction Credits

The emission reduction credits banked with the districts in the Sacramento 

Nonattainment Area are included in the unadjusted output of CEPAM2012. Table C5 

identifies the ERCs within CEPAM, as well as ERC updates provided by the 

Sacramento Nonattainment Area districts.

C-1
Table C1: Summer Planning Emissions Inventory for 

Nitrogen Oxides (NOx) in tons per day

Sacramento Nonattainment Area

Stationary Sources 2002 2014 2017 2018 2019

ELECTRIC UTILITIES 1.115 2.878 3.071 3.118 3.164

COGENERATION 0.011 0.009 0.010 0.010 0.011

OIL AND GAS PRODUCTION (COMBUSTION) 0.274 0.215 0.202 0.197 0.195

MANUFACTURING AND INDUSTRIAL 3.070 2.079 2.052 2.042 2.052

FOOD AND AGRICULTURAL PROCESSING 4.024 2.585 1.442 1.374 1.341

SERVICE AND COMMERCIAL 2.165 2.642 2.652 2.651 2.670

OTHER (FUEL COMBUSTION) 0.765 0.746 0.616 0.616 0.623

SEWAGE TREATMENT 0.012 0.021 0.022 0.022 0.022

LANDFILLS 0.037 0.066 0.067 0.067 0.068

INCINERATORS 0.019 0.020 0.021 0.021 0.022

SOIL REMEDIATION 0.003 0.005 0.005 0.005 0.005

OTHER (WASTE DISPOSAL) 0.000 0.000 0.000 0.000 0.000

LAUNDERING 0.000 0.000 0.000 0.000 0.000

DEGREASING 0.000 0.000 0.000 0.000 0.000

COATINGS AND RELATED PROCESS SOLVENTS 0.007 0.020 0.021 0.021 0.022

PRINTING 0.014 0.016 0.017 0.018 0.018

ADHESIVES AND SEALANTS 0.000 0.000 0.000 0.000 0.000

OTHER (CLEANING AND SURFACE COATINGS) 0.000 0.000 0.000 0.000 0.000

OIL AND GAS PRODUCTION 0.008 0.000 0.000 0.000 0.000

PETROLEUM REFINING 0.000 0.006 0.006 0.006 0.006

PETROLEUM MARKETING 0.020 0.032 0.034 0.035 0.037

OTHER (PETROLEUM PRODUCTION AND MARKETING) 0.000 0.000 0.000 0.000 0.000

CHEMICAL 0.160 0.291 0.325 0.337 0.353

FOOD AND AGRICULTURE 0.018 0.044 0.047 0.048 0.050

MINERAL PROCESSES 0.435 0.240 0.267 0.278 0.285

METAL PROCESSES 0.000 0.005 0.005 0.005 0.005

WOOD AND PAPER 0.056 0.045 0.047 0.047 0.047

ELECTRONICS 0.000 0.000 0.000 0.000 0.000

OTHER (INDUSTRIAL PROCESSES) 0.002 0.005 0.007 0.008 0.008

Stationary Sources Subtotal 12.212 11.969 10.935 10.924 11.000

Area-Wide Sources 2002 2014 2017 2018 2019

CONSUMER PRODUCTS 0.00 0.00 0.00 0.00 0.00

ARCHITECTURAL COATINGS AND RELATED PROCESS SOLVENTS 0.00 0.00 0.00 0.00 0.00

PESTICIDES/FERTILIZERS 0.00 0.00 0.00 0.00 0.00

ASPHALT PAVING / ROOFING 0.00 0.00 0.00 0.00 0.00

RESIDENTIAL FUEL COMBUSTION 2.53 2.74 2.56 2.50 2.45

FARMING OPERATIONS 0.00 0.00 0.00 0.00 0.00

CONSTRUCTION AND DEMOLITION 0.00 0.00 0.00 0.00 0.00

PAVED ROAD DUST 0.00 0.00 0.00 0.00 0.00

UNPAVED ROAD DUST 0.00 0.00 0.00 0.00 0.00

FUGITIVE WINDBLOWN DUST 0.00 0.00 0.00 0.00 0.00

FIRES 0.01 0.02 0.02 0.02 0.02

MANAGED BURNING AND DISPOSAL 0.53 0.58 0.57 0.57 0.57

COOKING 0.00 0.00 0.00 0.00 0.00

OTHER (MISCELLANEOUS PROCESSES) 0.00 0.00 0.00 0.00 0.00

Area-Wide Sources Subtotal 3.065 3.331 3.149 3.087 3.037

C-2
On-Road Mobile Sources 2002 2014 2017 2018 2019

LIGHT DUTY PASSENGER (LDA) 18.29 5.23 3.80 3.44 3.14

LIGHT DUTY TRUCKS - 1 (LDT1) 5.84 1.58 1.24 1.13 1.05

LIGHT DUTY TRUCKS - 2 (LDT2) 11.74 3.47 2.46 2.21 2.00

MEDIUM DUTY TRUCKS (MDV) 7.28 5.10 4.15 3.87 3.60

LIGHT HEAVY DUTY GAS TRUCKS - 1 (LHDV1) 1.30 2.49 2.27 2.20 2.12

LIGHT HEAVY DUTY GAS TRUCKS - 2 (LHDV2) 0.36 0.17 0.15 0.14 0.14

MEDIUM HEAVY DUTY GAS TRUCKS (MHDV) 0.89 0.44 0.34 0.32 0.29

HEAVY HEAVY DUTY GAS TRUCKS (HHDV) 0.51 0.27 0.27 0.27 0.27

LIGHT HEAVY DUTY DIESEL TRUCKS - 1 (LHDV1) 3.12 6.93 5.70 5.31 4.94

LIGHT HEAVY DUTY DIESEL TRUCKS - 2 (LHDV2) 2.04 1.39 1.16 1.09 1.02

MEDIUM HEAVY DUTY DIESEL TRUCKS (MHDV) 12.79 6.22 4.38 3.95 3.55

HEAVY HEAVY DUTY DIESEL TRUCKS (HHDV) 30.47 14.13 10.54 9.79 9.21

MOTORCYCLES (MCY) 0.32 0.58 0.59 0.60 0.60

HEAVY DUTY DIESEL URBAN BUSES (UB) 1.38 1.00 0.98 0.97 0.96

HEAVY DUTY GAS URBAN BUSES (UB) 0.12 0.11 0.11 0.10 0.10

SCHOOL BUSES - GAS (SBG) 0.06 0.03 0.03 0.03 0.03

SCHOOL BUSES - DIESEL (SBD) 0.52 0.37 0.37 0.34 0.33

OTHER BUSES - GAS (OBG) 0.17 0.18 0.15 0.15 0.14

OTHER BUSES - MOTOR COACH - DIESEL (OBC) 0.73 0.36 0.24 0.21 0.19

ALL OTHER BUSES - DIESEL (OBD) 0.44 0.27 0.19 0.18 0.17

MOTOR HOMES (MH) 0.71 0.41 0.36 0.34 0.33

On-Road Mobile Sources Subtotal 99.062 50.756 39.486 36.642 34.172

Other Mobile Sources 2002 2014 2017 2018 2019

AIRCRAFT 1.68 2.50 2.79 2.85 2.90

TRAINS 12.10 7.21 7.20 7.09 7.00

OCEAN GOING VESSELS 0.15 0.08 0.08 0.08 0.07

COMMERCIAL HARBOR CRAFT 2.04 1.30 0.88 0.86 0.85

RECREATIONAL BOATS 2.36 2.30 2.29 2.28 2.28

OFF-ROAD RECREATIONAL VEHICLES 0.04 0.08 0.09 0.10 0.10

OFF-ROAD EQUIPMENT 19.08 8.90 7.96 7.30 6.86

FARM EQUIPMENT 12.98 7.33 5.80 5.32 4.88

FUEL STORAGE AND HANDLING 0.00 0.00 0.00 0.00 0.00

Other Mobile Sources Subtotal 50.436 29.710 27.097 25.871 24.934

2002 2014 2017 2018 2019

Grand Total 164.776 95.766 80.666 76.524 73.143

Base Year: 2005

Sacramento Ozone Nonattainment Area Ver. 1.02

Migration ID: 2012_SIP_V102_SAC_O3

AF Migration Table: AF_MASTER_SIP12SNOZ

C-3
Table C2: Summer Planning Emissions Inventory for 

Volatile Organic Compounds (VOC) in tons per day

Sacramento Nonattainment Area

Stationary Sources 2002 2014 2017 2018 2019

ELECTRIC UTILITIES 0.168 0.402 0.420 0.425 0.426

COGENERATION 0.003 0.000 0.000 0.000 0.000

OIL AND GAS PRODUCTION (COMBUSTION) 0.154 0.083 0.078 0.076 0.075

MANUFACTURING AND INDUSTRIAL 0.070 0.123 0.123 0.123 0.122

FOOD AND AGRICULTURAL PROCESSING 0.355 0.195 0.115 0.110 0.106

SERVICE AND COMMERCIAL 0.221 0.262 0.266 0.266 0.266

OTHER (FUEL COMBUSTION) 0.089 0.044 0.033 0.033 0.033

SEWAGE TREATMENT 0.030 0.057 0.058 0.060 0.061

LANDFILLS 0.362 0.547 0.570 0.582 0.588

INCINERATORS 0.006 0.004 0.004 0.004 0.004

SOIL REMEDIATION 0.081 0.113 0.120 0.122 0.123

OTHER (WASTE DISPOSAL) 0.213 0.293 0.303 0.308 0.310

LAUNDERING 0.047 0.061 0.064 0.065 0.066

DEGREASING 2.464 2.133 2.197 2.217 2.231

COATINGS AND RELATED PROCESS SOLVENTS 3.019 4.102 4.309 4.397 4.453

PRINTING 1.219 1.494 1.573 1.599 1.620

ADHESIVES AND SEALANTS 0.827 0.889 0.884 0.880 0.877

OTHER (CLEANING AND SURFACE COATINGS) 0.003 0.018 0.019 0.019 0.019

OIL AND GAS PRODUCTION 0.799 0.568 0.531 0.519 0.507

PETROLEUM REFINING 0.000 0.000 0.000 0.000 0.000

PETROLEUM MARKETING 3.855 5.603 5.890 5.985 6.031

OTHER (PETROLEUM PRODUCTION AND MARKETING) 0.000 0.005 0.006 0.006 0.006

CHEMICAL 2.052 2.697 3.024 3.141 3.221

FOOD AND AGRICULTURE 0.518 0.581 0.617 0.630 0.641

MINERAL PROCESSES 0.218 0.181 0.201 0.209 0.212

METAL PROCESSES 0.000 0.000 0.000 0.000 0.000

WOOD AND PAPER 0.696 0.649 0.677 0.687 0.687

ELECTRONICS 0.006 0.023 0.025 0.025 0.027

OTHER (INDUSTRIAL PROCESSES) 0.002 0.049 0.070 0.080 0.083

Stationary Sources Subtotal 17.475 21.176 22.176 22.569 22.793

Area-Wide Sources 2002 2014 2017 2018 2019

CONSUMER PRODUCTS 14.760 12.575 12.999 13.160 13.281

ARCHITECTURAL COATINGS AND RELATED PROCESS SOLVENTS 8.449 8.827 9.176 9.291 9.380

PESTICIDES/FERTILIZERS 1.799 1.176 1.171 1.169 1.165

ASPHALT PAVING / ROOFING 0.821 0.908 0.917 0.920 0.921

RESIDENTIAL FUEL COMBUSTION 2.893 2.062 2.053 2.049 2.038

FARMING OPERATIONS 2.620 2.763 2.763 2.763 2.756

CONSTRUCTION AND DEMOLITION 0.000 0.000 0.000 0.000 0.000

PAVED ROAD DUST 0.000 0.000 0.000 0.000 0.000

UNPAVED ROAD DUST 0.000 0.000 0.000 0.000 0.000

FUGITIVE WINDBLOWN DUST 0.000 0.000 0.000 0.000 0.000

FIRES 0.036 0.046 0.048 0.049 0.049

MANAGED BURNING AND DISPOSAL 0.981 1.018 1.003 0.998 0.990

COOKING 0.111 0.137 0.142 0.143 0.144

OTHER (MISCELLANEOUS PROCESSES) 0.000 0.000 0.000 0.000 0.000

Area-Wide Sources Subtotal 32.470 29.511 30.271 30.541 30.722

C-4
On-Road Mobile Sources 2002 2014 2017 2018 2019

LIGHT DUTY PASSENGER (LDA) 22.904 6.956 4.805 4.260 3.851

LIGHT DUTY TRUCKS - 1 (LDT1) 7.561 2.566 1.989 1.840 1.748

LIGHT DUTY TRUCKS - 2 (LDT2) 8.342 3.250 2.533 2.361 2.230

MEDIUM DUTY TRUCKS (MDV) 3.988 3.757 3.461 3.375 3.289

LIGHT HEAVY DUTY GAS TRUCKS - 1 (LHDV1) 1.040 1.532 1.360 1.309 1.260

LIGHT HEAVY DUTY GAS TRUCKS - 2 (LHDV2) 0.718 0.100 0.078 0.071 0.066

MEDIUM HEAVY DUTY GAS TRUCKS (MHDV) 1.256 0.323 0.214 0.182 0.162

HEAVY HEAVY DUTY GAS TRUCKS (HHDV) 0.458 0.104 0.068 0.057 0.052

LIGHT HEAVY DUTY DIESEL TRUCKS - 1 (LHDV1) 0.126 0.418 0.371 0.355 0.339

LIGHT HEAVY DUTY DIESEL TRUCKS - 2 (LHDV2) 0.080 0.081 0.075 0.073 0.070

MEDIUM HEAVY DUTY DIESEL TRUCKS (MHDV) 0.712 0.324 0.228 0.216 0.205

HEAVY HEAVY DUTY DIESEL TRUCKS (HHDV) 1.610 0.683 0.627 0.639 0.651

MOTORCYCLES (MCY) 2.409 2.204 2.161 2.172 2.180

HEAVY DUTY DIESEL URBAN BUSES (UB) 0.060 0.046 0.046 0.045 0.045

HEAVY DUTY GAS URBAN BUSES (UB) 0.079 0.042 0.040 0.040 0.040

SCHOOL BUSES - GAS (SBG) 0.084 0.034 0.028 0.027 0.026

SCHOOL BUSES - DIESEL (SBD) 0.038 0.008 0.008 0.006 0.006

OTHER BUSES - GAS (OBG) 0.127 0.070 0.064 0.061 0.059

OTHER BUSES - MOTOR COACH - DIESEL (OBC) 0.037 0.011 0.010 0.011 0.011

ALL OTHER BUSES - DIESEL (OBD) 0.034 0.013 0.006 0.006 0.006

MOTOR HOMES (MH) 0.281 0.058 0.040 0.035 0.032

On-Road Sources Subtotal 51.944 22.580 18.210 17.140 16.327

Other Mobile Sources 2002 2014 2017 2018 2019

AIRCRAFT 0.543 0.653 0.614 0.622 0.630

TRAINS 0.636 0.402 0.357 0.340 0.325

OCEAN GOING VESSELS 0.006 0.004 0.003 0.003 0.003

COMMERCIAL HARBOR CRAFT 0.132 0.105 0.093 0.093 0.093

RECREATIONAL BOATS 20.284 13.742 12.325 11.888 11.464

OFF-ROAD RECREATIONAL VEHICLES 2.430 2.543 2.535 2.540 2.547

OFF-ROAD EQUIPMENT 10.877 7.499 6.792 6.589 6.437

FARM EQUIPMENT 2.672 1.410 1.086 0.987 0.902

FUEL STORAGE AND HANDLING 3.078 1.564 1.409 1.372 1.337

Other Mobile Sources Subtotal 40.658 27.923 25.213 24.433 23.737

2002 2014 2017 2018 2019

Grand Total 142.547 101.190 95.869 94.683 93.580

Base Year: 2005

Sacramento Ozone Nonattainment Area Ver. 1.02

Migration ID: 2012_SIP_V102_SAC_O3

AF Migration Table: AF_MASTER_SIP12SNOZ

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Table C3: Emissions Inventory Adjustments for 

Nitrogen Oxides (NOx) in tons per day

Sacramento Nonattainment Area

CEPAM 2012 2002 2014 2017 2018 2019

A. Unadjusted Emission Inventory 164.78 95.77 80.67 76.52 73.14

Updated Stationary/Area-Wide Sources 2002 2014 2017 2018 2019

B. Total Stationary/Area-Wide Source 

Adjustment 0.00 -0.03 -0.03 -0.03 -0.02

C. Implementation of PCAPCD 2421 0.00 -0.03 -0.03 -0.03 -0.02

Updated On-Road Mobile Inventory 2002 2014 2017 2018 2019

D. Total On-Road Mobile Inventory 

Adjustment 0.00 -2.21 -0.97 0.03 0.96

E. Updated EMFAC2011 Emissions2 0.00 -5.21 -2.97 -2.97 -2.043

F. Transportation Safety Margin4 0.00 3.00 2.00 3.00 3.00

Updated Incentives 2002 2014 2017 2018 2019

G. Total Incentive Adjustment 0.00 -1.71 -0.45 -0.49 -0.54

H. Carl Moyer 0.00 -1.64 -0.38 -0.42 -0.47

I. Prop 1-B 0.00 -0.07 -0.07 -0.07 -0.07

Updated Emission Reduction Credits 2002 2014 2017 2018 2019

J. Total Emission Reduction Credit 

Adjustment 0.00 0.73 0.81 0.81 0.82

K. 2008 Emission Reduction Credits 0.00 2.27 2.19 2.19 2.18

L. Current Emission Reduction Credits5 0.00 3.00 3.00 3.00 3.00

Emission Inventory Adjustment 2002 2014 2017 2018 2019

M. Total [A+B+D+G+K] 164.78 92.55 80.02 76.86 74.36

1 Appendix F - Table F5

2 Emissions updated using SACOG's 2013 MTIP and Solano's MTC Activity data received 11/30/12.

3 The EMFAC 2011 output for 2019 emissions are not adjusted for emission reductions from the Carl Moyer and 

Prop1B incentive programs, or the regulatory programs of RFG, Smog Check, AB1493 or ACC.

4 Data provided by SMAQMD, Brigette Tollstrup e-mail 12-05-12.

5 Appendix C - Table C3 Line A and B

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Table C4: Emissions Inventory Adjustments for Volatile Organic 

Compounds (VOC) in tons per day

Sacramento Nonattainment Area

CEPAM 2012 2002 2014 2017 2018 2019

A. Unadjusted Emission Inventory 142.55 101.19 95.87 94.68 93.58

Updated Stationary/Area-Wide Sources 2002 2014 2017 2018 2019

B. Total Stationary/Area-Wide Source 

Adjustment 4.11 4.01 3.99 3.99 3.98

C. Added Heritage Dairy (Yolo-Solano)1 0.00 0.11 0.11 0.11 0.11

D. Added Jepson Composting (Yolo-Solano)1 4.11 4.11 4.11 4.11 4.11

E. Implementation of FRAQMD 3.20 0.00 0.00 0.00 0.00 0.00

F. Implementation of PCAPCD 2431 0.00 -0.21 -0.22 -0.23 -0.23

Updated On-Road Mobile Inventory 2002 2014 2017 2018 2019

G. Total On-Road Mobile Inventory 

Adjustment 0.00 0.22 -0.61 -0.65 1.50

H. Updated EMFAC2011 Emissions2 0.00 -1.78 -1.61 -1.65 0.503

I. Transportation Safety Margin4 0.00 2.00 1.00 1.00 1.00

Updated Incentives 2002 2014 2017 2018 2019

J. Total Incentive Adjustment 0.00 -0.19 -0.03 -0.01 0.00

K. Carl Moyer 0.00 -0.19 -0.03 -0.01 0.00

Updated Emission Reduction Credits 2002 2014 2017 2018 2019

L. Total Emission Reduction Credit 

Adjustment 0.00 0.74 0.72 0.71 0.70

M. 2008 Emission Reduction Credits 0.00 3.26 3.28 3.29 3.30

N. Current Emission Reduction Credits5 0.00 4.00 4.00 4.00 4.00

Emission Inventory Adjustment 2002 2014 2017 2018 2019

O. Total [A+B+G+J+L] 146.66 105.96 99.94 98.72 99.77

1 Appendix F - Table F5

2 Emissions updated using SACOG's 2013 MTIP and Solano's MTC Activity data received 11/30/12.

3 The EMFAC 2011 output for 2019 emissions are not adjusted for emission reductions from the Carl Moyer and 

Prop1B incentive programs, or the regulatory programs of RFG, Smog Check, AB1493 or ACC.

4 Data provided by SMAQMD, Brigette Tollstrup e-mail 12-05-12.

5 Appendix C - Table C3 Line A and B

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Table C5: Emission Reduction Credits Added to the 

Emission Inventory Forecasts

Updated NOx ERC Emissions in tons/day1 2002 2014 2017 2018 2019

A. Total Sacramento Nonattainment Area NOx 

ERCs 0.00 3.00 3.00 3.00 3.00

CEPAM 2012 NOx ERC Emissions in tons/day 2002 2014 2017 2018 2019

B. Total ERCs 0.00 2.27 2.19 2.19 2.18

El Dorado 0.000 0.000 0.000 0.000 0.000

Placer County 0.000 0.403 0.403 0.403 0.404

Sacramento 0.000 1.188 1.153 1.146 1.140

Sutter 0.000 0.071 0.058 0.057 0.056

Yolo/Solano 0.000 0.610 0.581 0.579 0.578

ERC NOx Correction 2002 2014 2017 2018 2019

C. ERC Correction Value [A-B] 0.00 0.73 0.81 0.81 0.82

Updated VOC ERC Emissions in tons/day1 2002 2014 2017 2018 2019

A. Total Sacramento Nonattainment Area VOC 

ERCs 0.00 4.00 4.00 4.00 4.00

CEPAM 2012 VOC ERC Emissions in tons/day 2002 2014 2017 2018 2019

B. Total ERCs 0.00 3.26 3.28 3.29 3.30

El Dorado 0.000 0.000 0.000 0.000 0.000

Placer County 0.000 0.541 0.544 0.545 0.546

Sacramento 0.000 2.139 2.154 2.160 2.165

Sutter 0.000 0.061 0.060 0.060 0.060

Yolo/Solano 0.000 0.523 0.524 0.525 0.526

ERC VOC Correction 2002 2014 2017 2018 2019

C. ERC Correction Value [A-B] 0.00 0.74 0.72 0.71 0.70

1 ERCs as of 09/19/2013, provided by SMAQMD

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Appendix D

Reasonable Further Progress

Table D1: Sacramento Nonattainment Area 

Reasonable Further Progress Demonstration

2002 2014 2017 2018

Baseline ROG 146.7 106.0 99.9 98.7

CA MVCP/RVP Adjustment 0.0 10.9 11.9 12.2

RACT Corrections 0 0 0 0

Adjusted 2002 Baseline ROG in milestone year 146.7 135.8 134.8 134.5

RFP commitment for ROG reductions from new measures 0 0 0 0

Future Year ROG with existing and proposed measures 106.0 99.9 98.7

Required % change since previous milestone year 

(ROG or NOx) compared to 2002 9% 9% 3%

Target ROG levels 91.5 82.3 79.5

Apparent shortfall in ROG 14.5 17.6 19.2

Apparent shortfall in ROG, % 10.7% 13.0% 14.3%

ROG shortfall previously provided by NOx substitution, % 0.0% 10.7% 13.0%

Actual ROG shortfall, % 10.7% 2.3% 1.2%

Baseline NOx 164.8 92.6 80.0 76.9

CA MVCP Adjustment 0.0 10.4 11.0 11.2

Adjusted 2002 Baseline NOx in milestone year 164.8 154.4 153.8 153.6

RFP commitment for NOx reductions from new measures 0 0 0 0.0

Change in NOx since 2002 61.8 73.8 76.7

Change in NOx since 2002, % 40.0% 48.0% 49.9%

NOx reductions since 2002 already used for RFP substitution and 

contingency through last milestone year, % 0.0% 13.7% 16.0%

NOx reductions since 2002 available for RFP substitution and contingency in 

this milestone year, % 40.0% 34.3% 33.9%

Change in NOx since 2002 used for ROG substitution in this milestone year, 

% 10.7% 2.3% 1.2%

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, % 26.3% 31.9% 32.6%

RFP shortfall, if any 0.0% 0.0% 0.0%

RFP Met? YES YES YES

Contingency Met? YES YES YES

Note: ROG and NOx baseline emissions have been rounded to 1 decimal point.

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D-2
Appendix E

Transportation Conformity Baseline Adjustments

Attributed to Statewide Measures

Table E1: Sacramento Nonattainment Area NOx Motor 

Vehicle Baseline Emissions Adjustments in tons per day

2014 2017 2018

Adjustments to Baseline -2.15 -0.60 -0.66

RFG 0.00 0.00 0.00

Prop 1B -1.70 0.00 0.00

Moyer -0.08 -0.04 -0.05

AB1493 -0.01 -0.01 -0.01

Smog Check -0.37 -0.37 -0.33

ACC 0.00 -0.18 -0.28

Table E2: Sacramento Nonattainment Area VOC Motor 

Vehicle Baseline Emissions Adjustments in tons per day

2014 2017 2018

Adjustments to Baseline -2.63 -2.37 -2.26

RFG -1.87 -1.47 -1.31

Prop 1B 0.00 0.00 0.00

Moyer 0.00 0.00 0.00

AB1493 -0.11 -0.21 -0.25

Smog Check -0.64 -0.57 -0.55

ACC 0.00 -0.12 -0.15

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E-2
Appendix F

Unmonitored Area Analysis

Unmonitored Area Analysis for Ozone in Sacramento Nonattainment Area

Overview

The U.S. Environmental Protection Agency (U.S. EPA) requires that attainment 

demonstrations submitted as part of a State Implementation Plan (SIP) include an 

unmonitored area analysis (UAA). The UAA is intended to identify unmonitored areas 

where future year design values may be greater than the national ambient air quality 

standard (NAAQS). Since a simple spatial interpolation of observational data cannot 

identify unmonitored areas with concentrations higher than those measured at monitors, 

the U.S. EPA recommends a UAA that combines both observations and modeling. 

Although modeling is only as accurate as the emissions, meteorology, and 

representation of chemistry in the chemical mechanism, the model does explicitly 

account for the transport and formation of ozone over the entire modeling domain. 

Consequently, modeling can provide information about ozone concentration gradients 

between monitors that would not be accounted for in an analysis that includes only 

observational data.

Summary of Results

The monitoring network within the Sacramento 8-Hour Ozone Federal Nonattainment 

Area (Sacramento Nonattainment Area) was found to adequately capture elevated 

ozone levels within a 15-km radius of the monitors, and no peak concentrations were 

found outside of the network’s spatial coverage. Therefore, the UAA has identified no 

unmonitored areas with concentrations higher than those predicted at the monitors in 

the nonattainment year. Please note that a valid ozone design value in Solano County 

was not available for this analysis.

Methodology

Following U.S. EPA guidance, this analysis used the Modeled Attainment Test Software 

(MATS), developed by the U.S. EPA, in the UAA. For this analysis, MATS was used 

with the default configuration. The default configuration in MATS involves using at least 

5 days that have model-simulated, reference year ozone concentrations greater than or 

equal to 70 ppb in each grid cell in order to calculate the RRF for each grid cell. If the 

model simulation does not produce concentrations of 70ppb or higher in a certain grid 

cell, then the RRF and the concentration in that grid cell are both set to -9 (plotted as 

white color in Figure 3 and Figure 4).

F-1
Using MATS, the UAA is comprised of four steps:

1. Interpolate ambient design value data to create a set of spatial fields.

Ambient 8-hour Ozone Design Value (DV) concentrations from within the 

modeling domain are input into MATS, which creates a gridded set of DV 

spatial fields based on ambient data. The same design values that were used 

in the monitor based model attainment test are used for the UAA (DVs for 

years 2000-2002, 2001-2003, and 2002-2004). Note that these three datasets 

are centered on the 2002 reference year for modeling and RRF development.

2. Adjust the spatial fields using 2002 reference year gridded model output 

gradients (2002, reference year values).

For the 2007 SV 8-hr ozone SIP, two five-day ‘base case’ ozone episodes 

were simulated (Base case episode days: July 9 – July 13, 1999 and 

July 29 – August 2, 2000). Reference year (2002) modeling was conducted 

using a projected 2002 emissions inventory along with episode-specific, base 

case meteorology for both of these episodes. The daily maximum 8-hr ozone 

concentration for 2002 was calculated for each day and each model grid cell, 

resulting in a total of ten daily spatial gradient distributions, each representing 

the daily maximum 8-hr ozone field for the respective modeled day. Eight 

days of data that met base case model performance criteria were then input 

into MATS to generate a single gradient- adjusted DV spatial field.

3. Apply gridded RRFs to the gradient adjusted spatial fields.

In addition to the DVs and reference year simulated ozone, MATS requires 

future year simulated ozone. The methodology of calculating the daily 

maximum 8-hr ozone for the reference year (Step 2) was also used in this step

to calculate a total of eight daily spatial gradient distributions for the future 

year, 2018. The MATS software uses the reference year (2002) and future 

year (2018) simulated ozone in each grid cell to calculate an average RRF for 

each grid cell. The future year gradient adjusted concentration is then 

calculated as the product of the RRF and base year gradient adjusted 

concentration.

4. Determine if any unmonitored areas are predicted to exceed the NAAQS in 

the future.

Results from Step 3 are analyzed to determine if any unmonitored regions are 

in violation of the NAAQS based on the future year gradient adjusted 

concentration.

F-2
Results

Results associated with each step of the UAA method described above are presented 

below (Figures 1-4). By default in the MATS analysis, a ‘monitored area’ is defined as a 

7-by-7 grid of 4km grid cells surrounding a monitoring station. This is intended to be 

consistent with the 15km radius of representativeness for ambient monitoring stations 

that is used in the modeled attainment test.

An analysis of the gradient adjusted future year concentrations for 2018 (Figure 4) 

shows that the monitoring network in the SV provides adequate coverage over the 

regions which experience elevated ozone levels within the valley. In particular, the 

network adequately captures elevated ozone levels within a 15-km radius of the 

monitors and no peak concentrations are found outside of the network’s spatial 

coverage. Therefore, the UAA has identified no unmonitored areas with concentrations 

higher than those predicted to occur at the monitors in the attainment year.

F-3
1. Interpolate reference year ambient data to create a set of spatial fields.

Figure 1 - Interpolated ambient concentrations (DV) from MATS for 2002.

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2. Adjust the spatial fields using gridded model output gradients

(reference year values).

Figure 2 - . Interpolated gradient adjusted reference year concentration

from MATS for 2002.

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3. Apply gridded model RRFs to the gradient adjusted spatial fields.

Figure 3 - Relative Response Factor from MATS for 2018.

F-6
4. Determine if any unmonitored areas are predicted to exceed the NAAQS in 

the future.

Figure 4 - Interpolated gradient adjusted future year concentration

from MATS for 2018.

F-7