Appendix C 

REVISED 

Interstate Transport State Implementation Plan (SIP) 

 for the 1997 8-hour Ozone Standard and PM2.5 

to satisfy the Requirements of Clean Air Act section 

110(a)(2)(D)(i) 

for the 

State of California 

(September 21, 2007)
(This page intentionally left blank.)
September 21, 2007 Appendix C 1 

Introduction 

Sections 110 (a)(1) and (2) of the Clean Air Act require states to submit SIPs that 

implement, maintain, and enforce a new or revised national ambient air quality 

standard within three years following promulgation of the standard. Among the 

SIP elements identified in Section 110(a)(2) is the requirement to address the 

transport of pollutants between states. This section also requires states to 

ensure that their SIP does not interfere with another state’s program to prevent 

significant deterioration of its air quality or interfere with visibility in another state. 

In April 2005, the U.S. EPA notified states of their failure to make the required 

SIP submission addressing interstate transport of pollutants related to ozone and 

PM2.5. This “failure to submit” finding for the required interstate transport SIPs 

started a 24-month clock for U.S. EPA to issue a final Federal Implementation 

Plan (FIP) for any state that does not submit a plan within that time period. 

On August 15, 2006, U.S. EPA issued guidance for submitting interstate 

transport or “Good Neighbor” SIPs. In accordance with that guidance, this 

document contains the findings that California meets the requirements of 

sections 110 (a)(1) and (2) of the Clean Air Act for both the 1997 federal 8-hour 

ozone standard and the federal PM2.5 standard. 

Closest Nonattainment Areas to California 

Ozone: The closest 8-hour ozone nonattainment areas (based on the 1997 

standard) are Las Vegas, Nevada, and Phoenix-Mesa, Arizona. However, the 

status of Clark County, Nevada (Las Vegas), is in flux. The County has 

requested a “clean data finding” from U.S. EPA based on data from 2004-2006 

that shows the area to be in attainment of the 1997 standard. If U.S. EPA makes 

that finding, Clark County will no longer be considered a nonattainment area. 

PM2.5: The closest PM2.5 nonattainment area is Libby, Montana. Libby is more 

than 900 miles away from the San Joaquin Valley, the nearest PM2.5 

nonattainment area in California. 

Evaluation of Significant Contribution to Nonattainment or Interference 

with Maintenance of Attainment Standards in Another State 

U.S. EPA did an analysis for its Clean Air Interstate Rule (CAIR) to identify states 

that were contributing significantly to nonattainment of PM2.5 and ozone in 

adjacent states. In the preamble to that rule, U.S. EPA stated that: 

“In analyzing significant contribution to nonattainment, we 

determined it was reasonable to exclude the Western U.S., 

including the States of Washington, Idaho, Oregon, California, 

Nevada, Utah and Arizona from further analysis due to geography, 
September 21, 2007 Appendix C 2

meteorology, and topography. Based on these factors, we 

concluded that the PM2.5 and 8-hour ozone nonattainment 

problems are not likely to be affected significantly by pollution 

transported across these States’ boundaries. Therefore, for the 

purpose of assessing State’s contributions to nonattainment in 

other States, we have only analyzed the nonattainment counties 

located in the rest of the U.S.”1

 (emphasis added) 

The meteorological discussions below provide more detail. 

Ozone: Ozone episodes over the Southwestern United States are normally 

associated with strong high pressure systems centered over the Southwest 

Desert. These meteorological patterns are characterized by clear skies, warm 

temperatures, and light winds and result in very stagnant conditions over the 

region. Ozone is not transported over long distances under these conditions. 

On occasion, the strong high pressure is weakly impacted by migrating low 

pressure systems over the Pacific Ocean. This has the dual effect of maintaining 

stagnant conditions over most of the region while allowing weak pressure 

systems to push air that is high above the surface eastward and to transport 

ozone trapped in this layer over long distances. The area most likely to be 

affected by this transport would be Clark County, Nevada. 

Clark County, Nevada, has conducted an air quality monitoring study in which 

they evaluated ozone episodes in Las Vegas. This study suggests that ozone 

concentrations in Clark County were affected by ozone transported from sources 

in California. While ARB has no definitive data regarding the transport of ozone 

into Nevada, we are working together with the Clark County Department of Air 

Quality and Environmental Management to explore the issue further and have 

offered our efforts as they conduct the Southwest Desert/Las Vegas Ozone 

Transport Study this year. 

PM2.5: The technical support document for the PM2.5 designation of Lincoln 

County, Montana (containing Libby, Montana) found that the nonattainment area 

is “localized within and around the vicinity of the town of Libby due to 

topographical features and meteorology in the area impacted by emissions.” 

Therefore, Libby, Montana’s nonattainment status is not affected by emissions 

produced in other areas and transported to the Libby area. 

It is important to note that whether or not emissions from California are 

transported to nonattainment areas in other states, California’s existing stringent 

motor vehicle control program, consumer product regulations, stationary source 

permitting, new source review programs, and new commitments outlined in the 

California SIP further strengthened by the 8-hour ozone and PM2.5 SIPs, will 

 

1 Rule to Reduce Interstate Transport of Fine Particulate Matter and Ozone (Interstate Air Quality 

Rule Preamble), 69 FR at 4581, January 30, 2004. 
September 21, 2007 Appendix C 3

result in steadily decreasing emissions. California’s emission control programs 

are the most sophisticated and aggressive in the country and will continue to 

push the air quality control envelope. This greatly reduces the likelihood that 

emissions from California will contribute significantly to nonattainment in any 

downwind state. 

Evaluation of interference with Prevention of Significant Deterioration 

Measures of any other State 

U.S. EPA guidance2

 for interstate transport SIPs advises states to make a SIP 

submission to confirm that major sources in the State are currently subject to 

prevention of significant deterioration (PSD) and nonattainment new source 

review (NNSR) preconstruction permitting programs that apply to the 1997 

8-hour ozone standard. 

For the PM2.5 standard, the guidance advises states to provide a SIP 

submission to confirm that major sources in the State are subject to PSD and 

NNSR permitting programs implemented in accordance with U.S. EPA’s interim 

guidance calling for use of PM10 as a surrogate for PM2.5 in the PSD and NNSR 

programs. 

In California, all areas are subject to some form of preconstruction program for 

ozone and PM2.5. These rules are as stringent or more stringent than the 

federal preconstruction programs (PSD and NNSR). For ozone, California is on 

track to submit SIPs per the Phase II 8-hour Ozone Implementation Rule. For 

PM 2.5, California’s preconstruction programs are being implemented in 

accordance with EPA’s interim guidance calling for the use of PM10 as a 

surrogate for PM2.5 emissions. 

The following air districts are in attainment of the 1997 federal 8-hour ozone and 

PM2.5 standards and have a SIP approved PSD rule: 

• Mendocino County Air Pollution Control District 

• Monterey Bay Unified Air Pollution Control District 

• Northern Sonoma County Air Pollution Control District 

• North Coast Unified Air Quality Management District 

• Sacramento Metro Air Quality Management District (PM2.5) 

On a case-by-case basis, U.S. EPA has delegated partial PSD permitting 

authority to the following air districts that are in attainment of the 1997 federal 

8-hour ozone and PM2.5 standards: 

 

2 Guidance for State Implementation Plan (SIP) Submissions to Meet Current Outstanding 

Obligations Under Section 110(a)(2)(D)(i) for the 8-Hour Ozone and PM2.5 National Ambient Air 

Quality Standards, memo from William T. Harnett to Regional Air Division Directors dated August 

15, 2006, Page 8. 
September 21, 2007 Appendix C 4

• Antelope Valley Air Quality Management District 

• Bay Area Air Quality Management District 

• San Diego Air Pollution Control District 

For all other areas that are in attainment of federal standards, U.S. EPA retains 

federal PSD permitting authority. 

The following air districts are nonattainment of the 1997 federal 8-hour ozone 

standard and have new source review rules or are on track to submit NSR rules 

as part of their 8-hour ozone SIP development process. These rules are or will 

be equivalent to or more stringent than the federal requirements. 

• Antelope Valley Air Quality Management District (Antelope Valley and 

Western Mojave Desert Nonattainment Area) 

• Amador County Air Pollution Control District (Central Mountain 

Counties Nonattainment Area) 

• Bay Area Air Quality Management District 

• Butte County Air Quality Management District 

• Calaveras County Air Pollution Control District (Central Mountain 

Counties Nonattainment Area) 

• El Dorado County Air Pollution Control District (Sacramento Federal 

Nonattainment Area) 

• Feather River Air Quality Management District (Sacramento Federal 

Nonattainment Area) 

• Imperial Air Pollution Control District 

• Kern County Air Pollution Control District (Eastern Kern Nonattainment 

Area) 

• Mariposa County Air Pollution Control District (Southern Mountain 

Counties Nonattainment Area) 

• Mojave Desert Air Pollution Control District (Antelope Valley and 

Western Mojave Desert Nonattainment Area) 

• Northern Sierra Air Quality Management District (Western Nevada 

County Nonattainment Area) 

• Placer County Air Pollution Control District (Sacramento Federal 

Nonattainment Area) 

• Sacramento Metropolitan Air Quality Management District 

(Sacramento Federal Nonattainment Area) 

• San Joaquin Valley Unified Air Pollution Control District 

• South Coast Air Quality Management District 

• Tuolumne County Air Pollution Control District (Southern Mountain 

Counties Nonattainment Area) 

• Ventura County Air Pollution Control District 

• Yolo Solano Air Quality Management District (Sacramento Federal 

Nonattainment Area) 
September 21, 2007 Appendix C 5

The following air districts are nonattainment of the federal PM2.5 standard and 

already have NSR rules in place for PM10. These rules are equivalent to or 

more stringent than the federal requirements: 

• South Coast Air Quality Management District 

• San Joaquin Valley Unified Air Pollution Control District 

Evaluation of Interference with Other States’ Measures Required to Meet 

Regional Haze and Visibility SIP Requirements 

U.S. EPA’s guidance3

 states that states and regional planning organizations are 

currently engaged in the task of identifying Class I areas impacted by each 

state’s emissions and developing strategies for addressing regional haze to be 

included in the States’ regional haze SIPs. Since these regional haze SIPs are 

not due until December 17, 2007, states will not be required to address this 

requirement until the Regional Haze SIPs are submitted. 

California is on track to submit its Regional Haze SIP by December 17, 2007. 

The Regional Haze SIP will address interstate regional haze impacts. 

 

3 Guidance for State Implementation Plan (SIP) Submissions to Meet Current Outstanding 

Obligations Under Section 110(a)(2)(D)(i) for the 8-Hour Ozone and PM2.5 National Ambient Air 

Quality Standards, memo from William T. Harnett to Regional Air Division Directors dated August 

15, 2006, Page 9.