## State of California

AIR RESOURCES BOARD

June 2011 

### RECOMMENDED AREA DESIGNATIONS FOR THE 2010 FEDERAL SULFUR DIOXIDE (SO 2 

### ) STANDARD

STAFF REPORT

California Environmental Protection Agency


# Air Resources Boardi TABLE OF CONTENTS

Page

BACKGROUND ........................................

................................................... ............... 1

SULFURE DIOXIDE AIR QUALITY........................

................................................... .. 1

EMISSIONS .........................................

................................................... .................... 3

RECOMMENDED AREA DESIGNATIONS ..................... ............................................ 4

SULFUR DIOXIDE MONITORING NETWORK REQUIREMENTS ... ......................... 5

SUMMARY ...........................................

................................................... .................... 6

APPENDIX 1: FIVE FACTOR ANALYSES

APPENDIX 2: 2009 1-HOUR SO2 DESIGN VALUESii LIST OF TABLES AND FIGURES

Page

FIGURE 1: Graph of 1-hour SO 2 Design Values at Highest Monitoring Sites in California ............

................................................... ...................... 2

TABLE 1: Recommended California Attainment Areas f or the Federal 1-Hour Sulfur Dioxide Standard ................... ......................................... 5

TABLE 2: Minimum Sulfur Dioxide Monitoring Require ments .................................... 61

BACKGROUND

This report provides the Air Resources Board’s (ARB ) recommendations on designations for the revised federal sulfur dioxide (SO 2 ) standard, based on air quality monitoring data for California.

On June 2, 2010, the United States Environmental Pr otection Agency (U.S. EPA) established a new primary 1-hour SO 2 standard of 75 parts per billion (ppb). At the same time, U.S. EPA revoked the 24-hour and annual average standards. In addition to changing the averaging time and level of the standa rd, U.S. EPA revised the ambient air monitoring and data reporting requirements for SO 2 . The final rule for the SO 2 standard was published in the Federal Register on June 22, 2 010 and can be accessed via the link below:

http://www.epa.gov/ttn/naaqs/standards/so2/fr/20100 622.pdf

SULFUR DIOXIDE AIR QUALITY

Routine Monitoring

California has attained the 24-hour and annual aver age standards since the late 1980s. In the early 1970s, peak 1-hour SO 2 concentrations in California were as high as 230 ppb, but by the early 1990s, had decreased to l ess than 50 ppb. Based on California’s routine monitoring network, in 2009, 1 -hour SO 2 concentrations are one tenth of 1970 levels, ranging from 3 ppb to 35 ppb. Figure 1 below shows the trends in 1-hour SO 2 concentrations for the South Central Coast, San Fr ancisco Bay Area and South Coast Air Basins. These urban areas have the highest level of SO 2 concentrations in California. Although the Nipomo site in the South Central Coast once had concentrations above the level of the 1-hour st andard, concentrations have decreased as a result of new emission control requi rements and revised permit requirements for a nearby refinery. The 20 year tr end shows that sites with the highest SO 2 concentrations in 2009 are well below the standard

.2 FIGURE 1 1-hour SO 2 Design Values at Highest Monitoring Sites in Calif ornia

Special Purpose Monitoring

In addition to the routine monitoring network, seve ral special purpose monitoring networks are operated in the South Coast and San Fr ancisco Bay Area. In the South Coast, the Port of Long Beach/Los Angeles Air Quali ty Monitoring Program collects data on criteria air pollutants, including SO 2 , to estimate ambient levels of pollution that are due to Port operational activities. Together, the two Ports operate six monitoring sites. At the Port of Los Angeles these sites are the Wilm ington Community Monitoring Station, the San Pedro Community Monitoring Station , the Outer Harbor site, and the Terminal Island Treatment Plant Station. The two s ites at the Port of Long Beach are the Inner and Outer Port sites. Terminal Island Tr eatment Plant Station (at the Port of Los Angeles) and the Inner Port site (at the Port o f Long Beach) are expected to have the highest exposure to emissions from port operati ons, as they are in direct proximity to terminal operations which use a large number of diesel engine sources. The 2010 1-hour SO 2 design value at the Terminal Island Treatment Stat ion was 59 ppm. The 1-hour SO 2 2010 design value at the Inner Port site was 62 pp b.

In the San Francisco Bay Area, 15 ground level moni tors are deployed at the region’s five petroleum refineries. These ground level moni tors, required under the Bay Area Air Quality Management District’s Regulation 9, are loc ated near or outside the facility property boundaries and monitor downwind near-sourc e concentrations as part of the facility operating permit requirements. Measuremen ts were collected at all 15 sites during the 2008 through 2010 timeframe, and all but one have valid 2010 1-hour SO 23

design values. The highest design values were 56 p pb, measured near the Chevron facility and 53 ppb measured near the Conoco facili ty.

EMISSIONS

ARB maintains a comprehensive Oxides of Sulfur (SO x ) inventory. Staff estimates that SO 2 comprises 97% of the SO x inventory. Additionally, in most combustion categ ories almost all SO x

will be SO 2 . Therefore, in this report, SO x emissions are used to represent SO 2 emissions.

Emissions of SO x

declined tremendously in California between 1990 a nd today. Statewide, emissions have decreased by 45% since 19 90. SO x emissions from stationary sources have decreased due to improved i ndustrial source controls and switching from fuel oil to natural gas for electric generation and industrial boilers. The SO x emissions from land-based on- and off-road gasolin e and diesel-fueled engines and vehicles have also decreased due to lower sulfu r content in the fuel, and regulations to reduce the sulfur content in fuel us ed by commercial harbor craft.

As SO x is emitted primarily from combustion of fuels, emi ssion control efforts have focused largely on reducing the content of sulfur i n fuels. California has required the use of ultra-low-sulfur diesel fuel for on-road veh icles since 2006. In 2007, the U.S. EPA followed suit, requiring the ultra-low sulfur c ontent (15ppm) in on-road diesel fuel sold in the United States. Off-road diesel fuel wa s required to transition to ultra-low sulfur by 2010. Railroad locomotive and marine die sel fuel was reduced to 500 ppm sulfur in 2007, and will change to ultra-low sulfur in 2012. By the end of 2014, all highway, off-road, locomotive and marine diesel fue l produced will be ultra-low-sulfur diesel.

Implementation of the revised SO 2 standard is focused on large stationary sources. U.S. EPA guidance suggests initial focus on those e mitting 100 tons per year or greater of SO 2 . States are required to identify and eventually c onduct air quality modeling of any sources that may be anticipated to contribute t o a violation of the revised SO 2 standard. SO x

emissions from stationary sources in California ar e a fraction of the levels in other parts of the country. The largest sources in the U.S. have emissions exceeding 100,000 tons per year. These are large f ossil fuel electrical generation facilities located in the eastern and southern stat es. In contrast, the largest source of SO x emissions in California, a refinery in the Bay Are a, has emissions of approximately 5,000 tons per year, and ranks 350 on the list of t op SO 2 emitters in the nation. In total, there are 34 facilities in California with emission s greater than 100 tons per year. ARB staff is working with air districts to conduct addi tional dispersion modeling as required by U.S. EPA.4

RECOMMENDED AREA DESIGNATIONS

ARB staff evaluated the available ambient SO 2 data and SO x emissions data to determine appropriate area designations throughout the State. The recommendations in this report are based on SO 2 air quality data collected between 2007 and 2009. The analysis was conducted for each monitoring site in the State for which data are available. Generally, the 99 th percentile is the fourth highest 1-hour SO 2 concentration measured during a year. However, if data are incom plete, a higher value may be used, in accordance with established U.S. EPA criteria.

ARB staff has conducted a five factor analysis to d etermine the appropriate designations and boundaries. The five factors reco mmended by U.S. EPA for the purposes of determining the appropriate attainment area boundaries include: jurisdictional boundaries, geography/topography, me teorology, emissions, and air quality data. No areas with monitors in California violate the federal 1-hour SO 2 standard.

Areas of the State where no monitors exist are gene rally more rural in nature. There are no facilities located in these air basins with significant SO x emissions (greater than 100 tons per year), and only two facilities with SO x emissions greater than 50 tons per year. In comparison to the rest of the state, tota l SO x emissions are low. Since the existing monitoring network indicates that all area s with monitors are well below the level of the standard, ARB staff conclude that area s without monitors should also be below the standard.

Therefore, ARB staff is recommending that all areas in California be designated attainment for the 1-hour SO 2 standard. The recommended area designations are summarized in Table 1 below. Staff is recommending the air basin as the appropriate boundary for all of the attainment areas. Air basi n boundaries were developed based on regions with similar meteorology and topography. The five factor analysis for each air basin is provided in Appendix 1. Design values for individual monitoring sites are provided in Appendix 2.5 Table 1 Area Designation Recommendations

Air Basin Name Recommended Designation 2009 DV SO2 (ppb) Mojave Desert Attainment 10
North Central Coast Attainment 11*

North Coast Attainment 5 Sacramento Valley Attainment 4*

Salton Sea Attainment 10 San Diego Attainment 17 San Francisco Bay Area Attainment 25 San Joaquin Valley Attainment 9* South Central Coast Attainment 35
South Coast Attainment 20 Great Basin Valleys Attainment n/a Lake County Attainment n/a
Mountain Counties Attainment n/a
Northeast Plateau Attainment n/a
Lake Tahoe Attainment n/a

* Design value is not considered complete under U.S. EPA criteria. While no other site exists in the basin with a valid design value, the indicated design value is representative of concentrations in the region.

SULFUR DIOXIDE MONITORING NETWORK REQUIREMENTS

The final rule for the primary SO 2 standard also specifies the minimum number of SO 2 monitoring sites that State and local air agencies must operate. The monitoring regulations require SO 2 monitors be placed in Core Based Statistical Areas (CBSAs) based on a population weighted emissions index (PWE I) for the area. The PWEI is calculated by multiplying the latest available SO 2 emission data within each CBSA by the population of the CBSA, and then dividing the r esult by one million. The final rule requires:

• Three SO 2 monitors in CBSAs with PWEI values of one million o r more;

• Two SO 2 monitors in CBSAs with PWEI values less than one m illion but greater than 100,000; and

• One SO 2 monitor in CBSAs with PWEI values greater than 5,0 00 but less than 100,000.6

California has thirty-five CBSAs with population ra nging from 17,000 to more than 12 million people. Table 2 lists the three CBSAs i n California that require SO 2 monitoring. In addition, Table 2 shows that these CBSAs either meet or exceed federal monitoring requirements for SO 2 . California’s monitoring network currently consis ts of 39 monitors, in excess of the 4 required monitors.

Table 2 Minimum Monitoring Requirements for Sulfur Dioxide

CBSA Counties in

CBSA SO2

emissions per CBSA (tpy) Population

(2009) PWEI

(Million
personstpy) Required

SO2 Monitors Existing

SO2 monitors Los Angeles-Long Beach-Santa Ana Los Angeles,

Orange 13,498 12,874,797 173,785 2 5 Riverside-SanBernardinoOntario Riverside, San

Bernardino 2,478 4,143,113 10,266 1 4

San FranciscoOakland-Fremont Alameda,

Contra Costa, San Francisco, San Mateo, Marin 12,669 4,317,853 54,702 1 9

SUMMARY

ARB has used California’s air quality monitoring an d emissions data to develop recommended area designations for U.S. EPA’s revise d 1-hour SO 2 standard. The statewide monitoring network shows no violations an d the highest concentrations are far below the new federal standard. A review of the st atewide monitoring data and SOx emissions shows that California attains the SO 2 standard. Therefore, ARB recommends all air basins in California be designated as attai nment. Additional dispersion modeling, for sources with SOx emissions greater than 100 ton s per year, will be provided to the U.S. EPA. ARB is working with air districts to com plete the required modeling and plans to submit the modeling results to the U.S. EPA late r this year.

# APPENDIX 1

FIVE FACTOR ANALYSES FOR

CALIFORNIA AIR BASINS

### APPENDIX 1 Five Factor Analyses

Air Basins Having Facilities Greater Than 100 Tons Per Year of SOx Emissions

I. San Francisco Bay Area Air Basin

II. South Coast Air Basin

III. San Joaquin Valley Air Basin

IV. Mojave Desert Air Basin

V. South Central Coast Air Basin

VI: Remaining Air Basins

Sacramento Valley Air Basin

San Diego Air Basin

Salton Sea Air Basin

North Central Coast Air Basin

Mountain Counties Air Basin

Great Basin Valleys Air Basin

Lake County Air Basin

Lake Tahoe Air Basin

Northeast Plateau Air Basin

### A-1

I. SAN FRANCISCO BAY AREA BASIN

Recommendation

Ambient air quality monitors in the San Francisco B ay Area Air Basin (Bay Area) show a 2009 1-hour sulfur dioxide (SO 2 ) design value of 25 parts per billion (ppb). Beca use this
value is well below the level of the federal standa rd, staff recommends the Bay Area be designated as attainment, based on the assessment p rovided below. The assessment
includes an evaluation of the five factors recommen ded by U.S. EPA for the purposes of determining the appropriate attainment area boundar ies: jurisdictional boundaries, geography/topography, and meteorology (collectively referred to as nature of the region), emission data, and air quality data. Addi tional dispersion modeling results will be provided to the U.S. EPA later this year to furt her support the attainment designation
recommendation.

Nature of the Region

The Bay Area is California’s second largest metropo litan region. The nine county area comprises all of Alameda, Contra Costa, Marin, Napa , San Francisco, San Mateo, and Santa Clara counties, the southern half of Sonoma C ounty, and the southwestern portion of Solano County. It includes a number of large cities, for example, San Francisco, Oakland, and San Jose. Overall, approxi mately 20% of California’s population resides in the Bay Area. The entire nin e county area falls under the jurisdiction of the Bay Area Air Quality Management District (Bay Area District or District), which has responsibility for developing and implementing rules and regulations
to control SO 2 emissions from stationary sources located in the r egion.

Although the Bay Area comprises a diverse landscape , the unifying feature of this region is the Bay itself, which is one of the large st natural harbors in the world. The Bay is oriented north-south and covers about 400 square miles of the region’s total 5,340 square miles. Surrounding the Bay are the Coast Ra nge Mountains, oriented northwest/southeast with elevations up to about 2,5 00 feet. Along the western and northern shores of the Bay are numerous headlands a nd peninsulas separated by small bays which lead into valleys and canyons in the sur rounding foothills. In contrast, much of the eastern side is bordered by a low plain that slopes up into the Berkeley Hills. The highest population densities occur in the heavily u rbanized areas surrounding the Bay. These urban centers give way to more suburban areas , to the north, south, and east. Although these areas are less densely populated, th ey are home to a significant number of people.

### A-2

As with most of California, the Bay Area exhibits t he typical wet winter/dry summer meteorological regime. Rainfall varies from more t han 20 inches along the coast to less
than 15 inches at inland locations. Because of the variety of terrain, air flow in the region can be complex, especially at the lowest lev els. This is particularly true when the airmass is stable and wind speeds are weak. Althou gh flow patterns vary, the Bay Area shows a general sea breeze circulation pattern with onshore flow during the day and offshore flow during the evening and overnight hour s. During the summer, surface temperatures over the Bay Area are determined in la rge part by the effect of differential heating between land and water surfaces. This proce ss produces a large-scale gradient across the region. The temperature difference betw een coastal locations and inland locations can be 35 degrees Fahrenheit (F) or more on many summer afternoons. At night, the difference is usually less than 10 degre es F. The coastal versus inland temperature extremes reverse during the winter mont hs, with smaller differences during the daytime and larger differences at night.

Emissions

Based on the Air Resources Board’s (ARB) 2008 emiss ion inventory, there were 22,448 tons per year of total SO x emissions in the Bay Area. Petroleum refining and combustion-related processes accounted for approxim ately 55% of the total emissions, while ocean going vessels accounted for an addition al 20% of the total. Another 15% of
the total SO x

emissions was attributable to the mineral processe s, chemical processes, and manufacturing and industrial fuel combustion ca tegories. The remaining fraction of
emissions was distributed over a number of small st ationary, area-wide, off-road, and on-road source categories.

Stationary sources are of particular interest becau se implementation of the federal
1-hour SO 2 standard is focused on determining whether large st ationary sources have the potential to result in violations of the standa rd. U.S. EPA guidance suggest initial focus on sources emitting more than 100 tons of SO x per year. Stationary sources account for the majority of SO x emissions in the Bay Area, and emissions from thes e sources have decreased. Figure 1, based on data fr om ARB’s facility emissions database, shows total SO x emissions from all stationary source facilities in the Bay Area during 1998 and 2008. Overall, stationary source f acility SO x emissions have been reduced by a third, down from 19,161 tons per year in 1998 to 12,744 tons per year in
2008.

### A-3 FIGURE 1

While the above information is based on ARB’s 2008 emission inventory, more recent data for specific large facilities are available fr om the Bay Area District. The remainder of this discussion centers on these large facilitie s because of EPA’s focus on their potential to violate the 1-hour standard. Based on the District’s 2009 emission data, there are nine stationary source facilities in the Bay Area with SO x emissions in excess of 100 tons per year. These sources are summarized in Table 1 and Figure 2.

TABLE 1 Bay Area Facilities with SO x Emissions Greater than 100 Tons per Year

0 5,000 10,000 15,000 20,000

SFEmissions (t/y) 

## Sulfur Oxides Emissions from ARB's Facilities Database - San Francisco Bay Area

1998 SOx (t/y) 2008 SOx (t/y)

Facility Name City County SOx Emissions
Valero Refining Company Benicia Solano 5,066.10 t/y
Shell Martinez Refinery Martinez Contra Costa 1,222 .50 t/y
Conoco Phillips Refining Rodeo Contra Costa 1,172.1 0 t/y
Tesoro Refining Martinez Contra Costa 588.6 t/y
ConocoPhillips Rodeo Contra Costa 500.4 t/y
Chevron Products Company Richmond Contra Costa 470. 4 t/y
Rhodia, Inc. Martinez Contra Costa 307.5 t/y
Lehigh Southwest Cement Cupertino Santa Clara 240. 2 t/y

General Chemical West LLC Richmond Contra Costa 163 .5 t/y

### A-4 FIGURE 2

Six of the large Bay Area sources are petroleum ref ining and processing facilities. Five of these petroleum-related facilities are located i n Contra Costa County, and one is located in Solano County. The remaining three faci lities are a cement plant located in Santa Clara County and two chemical manufacturing f acilities located in Contra Costa County. Together, these nine facilities emitted 9, 731 tons of SO x in 2009, representing about 38% of the total 2009 Bay Area SO x emissions.

The Bay Area District has reduced emissions from st ationary facilities through a combination of District rules controlling SO x emissions, permitting requirements, and compliance with recent U.S. EPA consent agreements. The Bay Area District has two existing rules that control SO 2 emissions:

### A-5

* Regulation 9: Inorganic Gaseous Pollutants, Rule 1 : Sulfur Dioxide establishes emissions limits from stacks, as well a s ground-level concentration limits (beyond the facility property) for sulfur di oxide-emitting operations. There are specific limits for sulfur content in fuels, su lfur recovery plants, sulfuric acid plants, fluid catalytic cracking units, fluid coker s and coke calcining kilns, catalyst manufacturing plants, fresh fruit sulfuring operati ons, sulfur removal operations at petroleum refineries, and ships.

* Regulation 12: Miscellaneous Standards of Performa nce, Rule 12: Flares
at Petroleum Refineries requires reporting and analysis of any flaring emi ssion of over 500 lbs per day of sulfur dioxide. To redu ce future emisisons, the analysis is incorporated into flaring minimization plans.

In addition to these two rules, the Bay Area Distri ct implements two operating permit programs. Approximately 9,200 facilities have Dist rict operating permits which are renewed on an annual basis, in most cases. Permit renewal includes a review to determine if permit conditions are adequate to ensu re compliance with, and the enforceability of, applicable rules and regulations . Requirements for projects that would
increase SO 2 emissions include Best Available Control Technolog y (for sources that emit 10 pounds per day or more), offsets (for major sources that increase emissions by more than 1 ton per year), and air quality impact a nalysis which includes review for the
1-hour federal SO 2 standard (for major sources that would increase em issions by more than 40 tons per year). The permit review also inc ludes a compliance determination for other applicable rules and regulations.

Finally, SO 2 emissions from the largest SO x emission source in the Bay Area (as well as in California) have been significantly reduced as t he result of a U.S. EPA consent decree. The 2005 U.S. EPA consent decree required the Valero refinery to reduce sulfur dioxide emissions at their fluid catalytic c racking unit (FCCU). Valero installed a pre-scrubber for PM and sulfate removal and a regen erative amine scrubber for sulfur
dioxide. These controls abate emissions from the F CCU and from Valero’s coker,
which are vented to a common stack. The new emissi ons control equipment reduced
SO 2 emissions more than 90% -- from a potential to emi t of 6,222 tons per year to 416 tons per year.

In addition to existing controls, the Bay Area Dist rict included two upcoming rules in their 2010 Clean Air Act Plan. When formally adopt ed, these rules will further reduce
SO x emissions:

### A-6

SSM 8 - Coke Calcining : This measure will reduce SO 2 emissions from coke calcining by requiring a minimum 80% sulfur capture . In combination, the two coke calcining kilns at District Plant 22 (ConocoPh illips Carbon Plant) emit 1,232 tons of sulfur dioxide per year. The facilit y has committed to reducing SO 2 emissions by 42 tons per year to provide offsets fo r their Clean Fuels Expansion Project. The plant currently operates an abatement device to periodically trim
SO 2 emissions to maintain compliance with the current SO 2 emission limit in Regulation 9, Rule 1 of 400 ppm by volume or 113 kg (250 pounds) per hour,
whichever is more restrictive.

Similar to the proposed rule described above, the S outh Coast Air Quality Management District also requires a minimum 80% sul fur capture. The Bay Area’s proposed SSM 8 - Coke Calcining measure is i ntended to replicate the South Coast measure. Bay Area District staff expec t to take a proposed rule to
their Board in mid-2012.

SSM 9 - Cement Kilns: This control measure would reduce emissions of NOx

, SOx, mercury, and other toxic air contaminants from cement kilns. There is one cement manufacturing facility in the Bay Area: Leh igh Southwest Cement (plant #17). The proposed rule would require Lehig h to use abatement technology to reduce NOx emissions and to consider a wet scrubber to reduce
SO 2 emissions if any synergies in installing SO 2 controls along with NOx controls (or other controls) can be identified. Bay Area Di strict staff expects to take a proposed rule for cement kilns to their Board in 20 11.

Air Quality Trends

Ten SO 2 monitors were operated in the Bay Area during the 2007 through 2009 time period. An additional monitor recently began opera ting near the Lehigh Southwest Cement facility in Cupertino. These air quality mo nitors, shown in Figure 2, collect quality-assured data for record. Most of the Bay A rea monitors are located in and around the more heavily industrialized eastern port ion of the region. Several others are located downwind of the major source areas (refer t o Figure 2). Based on data collected during 2007 through 2009, six monitoring sites have valid design values. These design values range from 8 to 25 parts per bi llion (ppb), which is well below the level of the federal 1-hour standard. Although the remaining sites do not have valid design values for the three-year period, individual fourth high 1-hour measurements are well below the level of the standard, indicating th at design values for these sites would
also be below the standard.

### A-7

The monitoring site with the highest 1-hour SO 2 design value in the Bay Area is the Crockett-Kendall Avenue site in Contra Costa County . This site is located in the portion of the Bay Area that has the greatest density of st ationary SO 2 sources. The 2009 design value for the Crockett site is 25 ppb, which is well below the 75 ppb standard. The next highest design value is 18 ppb, measured a t both the Martinez-Jones Street
and Richmond-7 th Street sites. These sites are also located in Con tra Costa County, also in the vicinity of the largest SO 2 sources.

One-hour ambient SO 2 concentrations at Bay Area sites have decreased du ring the last 20 years. Figure 3 shows the trend for the three h ighest sites from 1990 through 2009. Although concentrations are variable from year-to-y ear, they show a 50% overall decrease. Design values for these sites have never been more than two-thirds the level of the federal standard, and in 2009, were no more than one-third the level of the standard. Design values for other sites in the Bay Area are even lower, ranging from 8 to 14 ppb in 2009. Monitoring sites in the Bay A rea are located both upwind and downwind of the main source area, indicating that p eople living in this region of California are not exposed to SO 2 concentrations above the level of the federal
standard.

FIGURE 3

0 10 20 30 40 50 60 70 80Federal 1-hour SO2 (ppb) 

## 1-Hour Federal SO2 Design Value

San Francisco Bay Area

Crockett-Kendall Avenue Martinez-Jones Street

Richmond-7th Street Fed 1-hr SO2 NAAQS (75 ppb)

### A-8

In addition to the long-term ambient monitoring net work, 15 ground level monitors are deployed at the five Bay Area petroleum refineries (refer to Figure 4). These ground level monitors, required under the District’s Regul ation 9, are located near or outside the facility property boundaries and monitor downwind n ear-source concentrations as part

FIGURE 4

of the facility operating permit requirements. Mea surements were collected at all 15 sites during the 2008 through 2010 timeframe, an d all but one have valid 2010
1-hour SO 2 design values. As summarized in Table 2, none of these sites had a design
value above the level of the federal standard. The highest design values were 56 ppb, measured near the Chevron facility and 53 ppb measu red near the Conoco facility (note that the monitor near the Conoco facility is missin g data for one quarter, but based on the other data collected at this site, it is highly unlikely the design value exceeded the standard).

### A-9 TABLE 2
2010 1-Hour SO 2 Design Values for Monitors Located Near Bay Area Petroleum Refineries

* Missing data for 1 quarter

Summary

Staff evaluated the five factors recommended by U.S . EPA for the purposes of determining attainment status and appropriate bound aries for federal SO 2 designations: jurisdictional boundaries, geography/topography, me teorology, emission data, and air quality data. Based on this analysis, violations o f the 1-hour SO 2 standard have not been measured over the last two decades, and violat ions are not expected to occur in the future. Therefore, staff recommends the San Fr ancisco Bay Area be designated as attainment, with the San Francisco Bay Area Air Bas in serving as the appropriate boundary for the attainment area. This recommendat ion is based on the following weight of evidence:

• The San Francisco Bay Area has a comprehensive SO 2 monitoring network, with monitoring sites located in the areas with the high est SO x emissions. Design values for all the Bay Area sites are well below th e level of the standard,

Refinery Site Design Value

Chevron 2201 56.3 ppb 2202 17.7 ppb 2203 31.7 ppb

Conoco 2263 53.3 ppb* 2265 3.3 ppb 2271 10.0 ppb 2273 36.7 ppb 2274 18.3 ppb Shell 2242 0.3 ppb

Tesoro 2251 36.7 ppb 2252 20.0 ppb 2253 10.0 ppb

Valero 8201 1.7 ppb 8202 3.0 ppb 8203 1.3 ppb

### A-10

including air quality monitoring data for the east Bay region, which has the greatest density of SO x sources and emissions;

• Emissions from SO x facilities have declined more than 30% since 1998 and are expected to continue declining as a result of conti nuing and anticipated District emission control programs;

• The San Francisco Bay Area Air Basin falls under the control of one jurisdiction: the Bay Area Air Quality Management District, and t he most effective air quality management will be achieved by including the entire air basin in the attainment

area;

• There are no specific meteorological, geographica l, or topographic factors that warrant a different boundary for the attainment are a; and

• Bay Area District staff are in the process of con ducting dispersion modeling for large local SO 2 sources, as described in the March 2011 U.S. EPA g uidance, and results of this modeling are expected to provid e further support for the attainment designation.

### A-11

II. SOUTH COAST AIR BASIN

Recommendation

Ambient air quality monitors in the South Coast Air Basin (South Coast) show a 2009 1-hour sulfur dioxide (SO 2 ) design value of 20 parts per billion (ppb), which is less than
one-third the level of the federal standard. Becau se this value is well below the standard, staff recommends the South Coast be desig nated as attainment, based on the assessment provided below. The assessment incl udes an evaluation of the five factors recommended by U.S. EPA for the purposes of determining the appropriate attainment area boundaries: jurisdictional boundar ies, geography/topography, and meteorology (collectively referred to as nature of the region), emission data, and air quality data. Dispersion modeling results will be provided to the U.S. EPA later this year to further support the attainment designation recom mendation.

Nature of the Region

The South Coast is California’s largest metropolita n region. The area includes the southern two-thirds of Los Angeles County, all of O range County, and the western urbanized portions of Riverside and San Bernardino counties. It covers a total of 6,480 square miles and is home to nearly 17 million people -- more than 40% of the State’s population. The South Coast falls under th e jurisdiction of the South Coast Air Quality Management District (District), which has r esponsibility for developing and implementing rules and regulations to control SO x emissions from stationary sources located in the region.

The South Coast region generally forms a lowland co astal plain, bounded by the Pacific Ocean on the west and by mountains on the other thr ee sides. Although the coastal plain comprises only about a third of the region’s land area, more than 80% of the South Coast population lives in the coastal area. The re gion boasts a diverse economic base. Historically, the four South Coast counties collect ively comprised one of the fastest growing local economies in the United States. Howe ver, the industrial base has realized significant changes over the last several decades. Similar to many other parts of the nation, a large segment of the heavy manufac turing sector, including steel and tire manufacturing and automobile assembly, has bee n phased out. These operations have been replaced by smaller service industries an d businesses that have developed as a result of growth in the regional shipping and trade sectors.

Overall, the South Coast region experiences more da ys of sunlight than any other major urban area in the nation except Phoenix. However, the climate does vary, from mild
near the coast to more extreme at inland locations. The coastal area benefits from the

### A-12

marine influence. This influence moderates tempera tures, and the daily onshore/offshore circulation pattern tends to dispe rse pollutants, which keeps pollutant concentrations low. Average temperatures in the co astal area vary from lows in the mid-50s to highs in the mid-70s, with annual precip itation ranging from 12 to 15 inches. Further inland, temperatures increase and precipita tion decreases. Average highs during the summertime can reach the mid- to high-90 s, with maximum daily temperatures over 100 degrees Fahrenheit common in many inland areas. Rainfall in some areas averages less than 10 inches per year. In contrast to the low elevation inland areas, the surrounding inland mountains reac h elevations of more than 10,000 feet. These areas see temperatures below freezing in the winter and precipitation in the
form of snow.

Emissions

There are 13,870 tons per year of total SO x emissions in the South Coast, based on the Air Resources Board’s (ARB) 2008 emission inven tory. The major sources are ocean-going vessels and related port industrial and freight activities. The South Coast is home to two major port facilities. The Port of Long Beach is the second busiest container port in the country and is considered one of the largest shipping ports in the world. It is located approximately two miles from downtown Long Beach and twenty miles south of downtown Los Angeles. Occupying 3,2 00 acres of land, the Port of Long Beach adjoins the neighboring Port of Los Angeles.

The remainder of this section addresses large SO 2 stationary sources in the South Coast because implementation of the federal 1-hour SO 2 standard is focused on determining whether large stationary sources have t he potential to result in violations of the standard. U.S. EPA guidance suggests initial f ocus on sources emitting more than
100 tons of SO x

per year. Figure 5, based on data provided by the South Coast District,
shows total SO x

emissions from all stationary source facilities in the South Coast during 1998 and 2008. Overall, stationary source SO x emissions have decreased 40%, down from 7,748 tons per year in 1998 to 4,570 tons per year in 2008.

There are eleven stationary source facilities with SO x emissions greater than 100 tons per year in the South Coast. All eleven f acilities are located in Los Angeles County and most are related to petroleum processing and transportation. Together, these facilities represent 84% of the total station ary source component of the South
Coast SO x

inventory. The map in Figure 6 shows the location s of the large SO x facilities. Seven of the facilities are located re latively close to one another, near the Port of Long Beach, south of the city of Los Angele s. The remaining four are scattered around the southern and central portions of the Cou nty. Table 3 provides a summary of the sources, their location, and their SO x emissions levels.

### A-13 FIGURE 5

FIGURE 6 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000Emissions (t/y) Sulfur Oxides Emissions from ARB's

Facilities Database - South Coast

1998 SOx (t/y) 2008 SOx (t/y)

### A-14 TABLE 3

South Coast Facilities with SO2 Emissions Greater t han 100 tons per year

Facility Name City County SOx Emissions

BP West Carson Refinery Carson Los Angeles 915 t/y

Chevron Products Company El Segundo Los Angeles 429 t/y

Rhodia Carson Los Angeles 426 t/y

Tesoro Refining & Marketing Wilmington Los Angeles 368 t/y

Ultramar Inc. (NSR use only) Wilmington Los Angeles 357 t/y

Exxon Mobil Oil Corporation Torrance Los Angeles 32 8 t/y

Conoco Phillips Company Carson Los Angeles 305 t/y

Conoco Phillips Company Wilmington Los Angeles 270 t/y

BP West Wilmington Wilmington Los Angeles 208 t/y

LA County Sanitation District City of Industry Los Angeles 142 t/y

Owens-Brockway Glass Vernon Los Angeles 100 t/y

The South Coast has the most stringent SO 2 control measures in the nation. These measures go far beyond what U.S. EPA has required i n recent settlement agreements
of similar facilities in California and the rest of the country. The South Coast District is in the process of submitting updates to their regul ations. Under their Regional Clean Air Incentives Market (RECLAIM) program, these updates will ensure an additional 2,080 tons per year reduction in SO x emissions. Of the total 2,080 ton reduction, more than half (1,095 tons) will be reduced by 2013. Al l of the large SO x facilities, with the exception of the Los Angeles County Sanitation Dist rict, are covered by these updated regulations, which are both verifiable and enforcea ble.

In addition to the stationary source SO x emission control measures adopted by the South Coast District, the ARB has a number of emiss ion control measures that will reduce emissions from port-related sources includin g cargo handling, commercial harbor craft, port trucks, and ship auxiliary and m ain engines. There are additional
substantial emission reduction efforts at the local level. The Ports of Long Beach and Los Angeles approved the San Pedro Bay Ports Clean Air Action Plan (Ports Plan) in 2006, which provides an overall strategy for reduci ng air pollution emissions from port-related cargo movement. Among the main elemen ts of the Ports Plan are requirements and incentives to reduce diesel truck- related emissions in the ports area and surrounding communities.

### A-15

Air Quality Trends

As mentioned earlier, there are seven SO 2 monitors in the South Coast that collect quality-assured data for record (refer to Figure 7) . Several of these monitors are located near (from 2 to 12 miles) the largest SO x facilities in Los Angeles County and are therefore well-sited for capturing the highest regional SO 2 concentrations. In addition to these monitors, several others are loca ted in Orange, Riverside, and San Bernardino counties. These sites monitor publi c SO 2 exposure from smaller facilities and from area wide transportation source s. Based on data for record collected during 2007 through 2009, the South Coast attains t he federal 1-hour SO 2 standard with design values for individual sites ranging from 6 p pb to 20 ppb, with design values for most sites below 10 ppb.

The monitoring site with the highest design value i n the South Coast is the North Long Beach site, located near the area with the highest density of major SO x emission sources. This site has a design value of 20 ppb, w hich is well below the level of the standard. The long-term trend in 1-hour SO 2 design values at North Long Beach is graphed in Figure 7. The trend line shows the valu e is now less than half what it was in 1998, and the design value has never violated the f ederal standard. Figure 7 also shows trend lines for two other long-term sites: B urbank and Riverside. These sites are located in the inland portions of Los Angeles a nd Riverside counties, respectively. In 2009, design values at these sites were less tha n half the value for North Long Beach, indicating that concentrations are much lowe r in areas further away from the
main source area near the coast.

In addition to the long-term SO 2 monitoring network, the ports of Long Beach and Los Angeles conduct special monitoring to measure a ir quality at the ports and in nearby communities. The ports monitoring network c ollects air quality (including SO 2 ) and weather data on a real-time basis to provide ti mely and accurate information on air quality in the ports region. The Port of Long Beac h operates two monitoring stations: one in the Inner Port area, near West Long Beach (a lso called Superblock), and the second in the Outer Port area, near the breakwater (also called Gull Park). The Port of Los Angeles operates four monitoring stations, loca ted in the Outer Harbor area at Berth 47, at the Terminal Island Treatment Plant, i n the community of San Pedro, and in the community of Wilmington. The six-monitor networ k was developed under the Green Port Policy and is used to better manage air qualit y improvement efforts. As shown in the Table 4, the three-year average of the 99 th percentile 1-hour concentration for the six ports sites ranged from 34 ppb to 62 ppb, all o f which are below the level of the
federal standard.

### A-16 FIGURE 7

TABLE 4
1-Hour SO 2 Design Values for Monitoring Sites Located at the Ports of Long Beach and Los Angeles

Site Port 2008-2010 Design Value
Inner Port (Superblock) Port of Long Beach 62 ppb Terminal Island Port of Los Angeles 53 ppb Outer Port (Gull Park) Port of Long Beach 47 ppb Outer Harbor Port of Los Angeles 47 ppb San Pedro Port of Los Angeles 44 ppb Wilmington Port of Los Angeles 34 ppb 0 10 20 30 40 50 60 70 80

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 200 2 2003 2004 2005 2006 2007 2008 2009Federal 1-hour SO2 (ppb) 1-Hour Federal SO2 Design Values
South Coast

North Long Beach Burbank-W Palm Avenue Riverside-Rubidoux Fed 1-hr SO2 NAAQS (75 ppb)

### A-17

Summary

Staff evaluated the five factors recommended by U.S . EPA for the purposes of determining attainment status and appropriate bound aries for federal SO 2 designations: jurisdictional boundaries, geography/topography, me teorology, emission data, and air quality data. Based on this analysis, violations o f the 1-hour SO 2 standard have not been measured over the last two decades, and violat ions are not expected to occur in the future. Therefore, staff recommends the South Coast be designated as attainment, with the South Coast Air Basin serving as the appro priate boundary for the attainment
area. This recommendation is based on the followin g weight of evidence:

• South Coast Air Basin has a comprehensive SO 2 monitoring network, with monitoring sites in the areas with the highest SO x emissions and expected highest concentrations. Design values for all the South Coast monitoring sites are well below the level of the standard, including monitoring data collected in the Long Beach/San Pedro area, which has the greatest d ensity of SO x sources and emissions;

• The South Coast has the most stringent SO x control measures in the nation;

• Stationary source SO x emissions decreased 40% between 1998 and 2008. Th e South Coast District is currently updating rules th at will ensure an additional 2,080 ton per year reduction in SO x emissions from large facilities participating in its RECLAIM program, and more than half the reducti on will occur by 2013;

• The South Coast Air Basin falls under the jurisdic tion of a single agency, the South Coast Air Quality Management District, and ef fective air quality management is best achieved by including the entire air basin in the attainment

area;

• There are no specific meteorological, geographical or topographic factors that warrant a different boundary for the attainment are a;

• South Coast District staff are in the process of c onducting dispersion modeling for large local SO x

sources, as described in the March 2011 U.S. EPA g uidance, and results of their modeling are expected to provi de further support for the attainment designation.

### A-18

III. SAN JOAQUIN VALLEY AIR BASIN

Recommendation

Ambient air quality monitoring in the San Joaquin V alley Air Basin (SJV or Valley) shows a 2009 1-hour sulfur dioxide (SO 2 ) design value of 9 parts per billion (ppb). Although this value is not considered valid under U .S. EPA’s criteria because data for one quarter are incomplete, it provides a good indi cation of SO 2 concentrations in relation to the standard. The preliminary design v alue for 2010, which is generally complete, is even lower, at 7 ppb. Because the two design values are so far below the level of the federal standard, staff recommends the San Joaquin Valley be designated as attainment, based on the assessment provided bel ow. The assessment includes an evaluation of the five factors recommended by U.S. EPA for the purposes of determining the appropriate attainment area boundar ies: jurisdictional boundaries, geography/topography, and meteorology (collectively referred to as nature of the region), emission data, and air quality data. Addi tional dispersion modeling results will be provided to the U.S. EPA later this year to furt her support the attainment designation
recommendation.

Nature of the Region

The San Joaquin Valley Air Basin is one of Californ ia’s largest air quality control regions. The eight-county area includes all of Fre sno, Kings, Madera, Merced, San Joaquin, Stanislaus, and Tulare counties, as we ll as the western portion of Kern County. Although the San Joaquin Valley (SJV or Va lley) was once primarily agricultural, urban and industrial development has increased substantially over the last several decades. About 10% of the State’s populati on, or about three million people, now live in the Valley. The entire region falls un der the jurisdiction of the San Joaquin Valley Air Pollution Control District (SJV District or District), which has responsibility for developing and implementing rules and regulations t o control SO 2 emissions from stationary sources.

The SJV occupies the southern two-thirds of Califor nia’s Central Valley and comprises nearly 23,500 square miles. With very few exceptio ns, the SJV is flat, with most of the area lying below 400 feet elevation. The long flat valley area is bordered by the Coast Range to the west, the Sierra Nevada to the east, t he Transverse Range to the south, and the Sacramento Valley to the north. In contras t to other California areas, the San Joaquin Valley is not dominated by one large ur ban area. Instead, there are a number of moderately sized urban areas spread along the main axis of the Valley. Most residents are distributed along the two major thoro ughfares: Highway 99 and Interstate 5. The Valley’s major population center s include the Fresno, Bakersfield, and
Stockton/Modesto urban areas.

### A-19

In general, the San Joaquin Valley experiences a cl imate with cool wet winters and hot dry summers. The northern Valley experiences a mor e temperate climate than the rest
of the SJV because it is located closer to the Paci fic Ocean, and the marine influence extends into the area through gaps in the Coast Ran ge Mountains. This keeps temperatures cooler and favors better air flow. Mo ving further down the Valley, maximum daily temperatures increase, and rainfall t otals decrease. From north to south, average maximum July temperatures increase f rom about 94 degrees Fahrenheit (F) at Stockton to nearly 99 degrees F at Fresno an d Bakersfield. In contrast, annual average rainfall decreases from north to south, ave raging 14 inches at Stockton, 11 inches at Fresno, and 6 inches at Bakersfield. The amount of stagnation and the complexity of local circulation patterns also incre ase from north to south. As a result, prevailing conditions in the central and southern p ortions of the SJV are more likely to trap pollutants and prevent their dispersal.

Emissions

Based on the Air Resources Board’s (ARB) 2008 emiss ion inventory, there were a total of 8,413 tons per year of SO x emissions in the San Joaquin Valley. The SO x inventory is dominated by stationary source emissions. Among the various stationary source categories, fuel combustion from manufacturing and industrial operations, oil and gas production, electric utilities, and service and com mercial operations account for more than half the SJV total. Industrial processes, inc luding glass and related products, mineral processes, chemical processes, and food and agricultural processes account for another third of the total. The remaining SO x emissions are distributed over a wide range of fuel combustion and miscellaneous processe s, including cogeneration, food and agricultural processes, petroleum refining, and managed burning and disposal operations.

U.S. EPA guidance suggests initial focus on sources emitting more than 100 tons of
SO x per year. In total, emissions from stationary sou rces in the SJV have decreased over the last decade. Figure 8, based on data from the ARB’s facility emission database, shows total SO x emissions from all stationary source facilities in the San Joaquin Valley during 1998 and 2008. Overall, stat ionary source SO x emissions decreased a little more than 50 percent between 199 8 and 2008 – from 6,021 tons per year to 2,947 tons per year.

### A-20 FIGURE 8

While the information in Figure 8 is based on ARB’s 2008 emission inventory, more recent data for the specific large local facilities are available from the SJV District. The remainder of this discussion centers on these large facilities because of EPA’s focus on their potential to violate the 1-hour standard. Ba sed on the District’s 2009 emission data, there are eight stationary source facilities in the San Joaquin Valley with emissions in excess of 100 tons per year. These so urces are summarized in Table 5 and Figure 9. Together, these eight facilities emi tted 1,899 tons of SO x in 2009, representing about 23% of the total SJV SO x inventory.

TABLE 5 San Joaquin Valley Facilities with SO x Emissions Greater than 100 Tons per Year

Facility Name City County SO x Emissions Chevron USA Inc. Kern County Kern 430.69 t/y J. R. Simplot Company Lathrop San Joaquin 359.13 t/y Gallo Glass Company Modesto Stanislaus 300.05 t/y Plains Exploration & Production Co Kern County Kern 231.25 t/y Owens-Brockway Glass Container, Inc. Tracy San Joaquin 226.46 t/y

Chevron USA Inc. Kern County Kern 130.97 t/y Pilkington North America, Inc Lathrop San Joaquin 1 14.67 t/y Stockton Cogen Company Stockton San Joaquin 106.02 t/y

0 5,000 10,000 15,000 20,000Emissions (t/y) 

## Sulfur Oxides Emissions from ARB's Facilities Database - San Joaquin Valley

1998 SOx (t/y) 2008 SOx (t/y)

### A-21 FIGURE 9

The large stationary source facilities reflect four general source types. The two Chevron facilities and the Plains Exploration and Productio n Company are crude oil and gas extraction facilities. All three use multiple boil ers, steam generators, and flares in their extraction processes. Another three facilities, Ow ens-Brockway Glass Container, Inc., Pilkington North America, Inc., and Gallo Glass Com pany manufacture glass, including container glass and flat glass. The J. R. Simplot Company in San Joaquin County produces sulfuric acid, which is used in the manufa cture of fertilizer. Finally, the Stockton Cogeneration Company is a solid fuels-fire d combined heat and power facility that supplies power for sale to PG&E, as well as st eam for local manufacturing. This facility has modified both its operations and its p ermit to include agriculturally-derived biomass in its fuel mix. The facility anticipates that an increased use of biomass will likely lower their SO 2 emissions in the coming years.

### A-22

The SJV District has reduced SO x emissions from large stationary sources through a
combination of rules and the use of low-sulfur Publ ic Utilities Commission-grade (PUC-grade) natural gas (natural gas that is low in sulfur and meets California PUC specifications). For many industries, the prevaili ng use of PUC-grade natural gas as the primary process fuel source minimizes SO 2 emissions. But most importantly, the SJV District has adopted stringent rules regulating SO 2 emissions. Table 6 summarizes the major District rules that apply to the Valley’s eight large stationary sources.

TABLE 6 San Joaquin Valley District Rules Applicable to Sta tionary Sources with

SO x Emissions of 100 Tons per Year or More

Rule Name 4306 Boilers, Steam Generators & Process Heaters >5 MMBtu/nr

4320 Advanced Emission Reduction Options for Boilers, St eam Generators & Process Heaters >5.0MMBtu/hr (AERO) 4354 Glass Melting Furnaces
4802 Sulfuric Acid Mist
4311 Flares

Rules 4306 and 4320 work together to require the most effective pollut ion controls for large boilers, steam generators, and process heater s. Although Rule 4306 is not directly aimed at reducing SO x emissions, SO x

emissions may be reduced, depending on the control method utilized. In contrast, Rule 4320 does directly target SO 2 emissions, with reductions estimated at 73% of base line levels.

Rule 4354 places stringent limits on NO x , VOC, CO, and SO x emissions from glass-melting furnaces. The Rule limits SO x emissions to between 0.9 and 1.7 pounds per ton of glass produced, depending on the type of glass furnace and firing technology. These limits are the most stringent in the nation.

Rule 4802 limits sulfuric acid mist emissions from existing s ulfuric acid production units by limiting the discharge of effluent process gas t o no more than 0.30 pounds of gas per short ton of sulfuric acid produced.

Rule 4311 regulates emissions from combustion in flares asso ciated with oil and gas production. Amendments adopted in 2009 added SO x emission limits, which will reduce
SO x emissions by 66% from baseline levels.

### A-23

Air Quality Trends

There is one monitor in the San Joaquin Valley that collects quality assured data for record. This monitor, Fresno-1 st Street, is located in the downtown portion of Fres no. The map in Figure 9 shows the location of the Fresn o-1 st Street monitor. Based on available 2007 through 2009 data, the design value for the Fresno monitor is 9 parts per billion (ppb), which is well below the 75 ppb feder al 1-hour standard. However, the design value is not considered complete under U.S. EPA criteria, because data for January and February 2007 are missing. Based on da ta for 2008 through 2010, which are generally complete, the site has a preliminary design value of 7 ppb. The long-term
trend in SO 2 design values for the Fresno-1 st Street is shown in Figure 10 and shows that concentrations have decreased 70% since 1990, dropping from 30 ppb to 9 ppb. Throughout the entire time period, the design value has been less than half the level of
the federal standard.

Although Fresno-1 st Street is the only SO 2 monitor currently operating in the San Joaquin Valley, data are available from a numbe r of other monitors that were in operation during the mid-1970s through late-1990s. Several sites located in and around
the Bakersfield urban area showed 4 th high 1-hour SO 2 concentrations up to 130 ppb during the late-1970s to mid-1980s, but these conce ntrations dropped to the 10 to 20 ppb range by the early 1990s. Other sites locat ed throughout the Valley showed
4 th high 1-hour measurements in the range of 10 to 20 ppb during the 1980s. Monitoring at most of these sites, including sites in Stockton, Modesto, Oildale, and Visalia, was discontinued by 1990. None of these h istoric sites violated the federal
1-hour SO 2 standard at the time monitoring was stopped. Beca use SO x emissions are now lower, it is unlikely the federal standard is c urrently violated anywhere in the San Joaquin Valley. As discussed earlier, in addit ion to these air quality data, dispersion modeling for large stationary sources in the SJV will be provided when available, to further support the recommended attai nment designation.

### A-24 FIGURE 10

Summary

Staff evaluated the five factors recommended by U.S . EPA for the purposes of determining attainment status and appropriate bound aries for federal SO 2 designations: jurisdictional boundaries, geography/topography, me teorology, emission data, and air quality data. Based on this five factor analysis, violations of the 1-hour SO 2 standard have not been measured over the last two decades, a nd violations are not expected to occur in the future. Therefore, staff recommends t he San Joaquin Valley be designated as attainment, with the San Joaquin Valley Air Basi n serving as the appropriate boundary for the attainment area. This recommendat ion is based on the following weight of evidence:

• The design value for Fresno-1 st Street decreased over the last two decades and
is now well below the level of the federal 1-hour S O 2 standard. Evaluation of historic data for other sites located throughout th e San Joaquin Valley also indicate long-term levels below the standard; 0 10 20 30 40 50 60 70 80

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008Federal 1-hour SO2 (ppb) 1-Hour Federal SO2 Design Value San Joaquin Valley

Fresno-1st Street Fed 1-hr SO2 NAAQS (75 ppb)

### A-25

• SO x emissions from stationary source facilities in the SJV declined 50% in the last ten years as a result of District emission con trol measures, and they will continue to decline in the future;

• The entire San Joaquin Valley falls under the jur isdiction of the San Joaquin Valley Air Pollution Control District, and effectiv e air quality management is best achieved by including the entire Air Basin in the a ttainment area;

• There are no specific meteorological or geographi c/topographic factors that support an attainment area boundary different from the Air Basin boundary; and

• SJV District staff are in the process of conducti ng dispersion modeling for large local stationary SO 2 sources, as described in the March 2011 U.S. EPA guidance, and results of this modeling are expected to provide further support for the attainment designation. The District is also c onsidering modeling additional
facilities with SO x

emissions under 100 tons per year.

### A-26

IV. MOJAVE DESERT AIR BASIN

Recommendation

Ambient air quality monitoring in the Mojave Desert Air Basin (Mojave Desert) shows a 2009 1-hour sulfur dioxide (SO 2 ) design value of 10 parts per billion (ppb). Beca use this
value is well below the level of the federal standa rd, staff recommends the Mojave Desert be designated as attainment, based on the as sessment provided below. The
assessment includes an evaluation of the five facto rs recommended by U.S. EPA for the purposes of determining the appropriate attainm ent area boundaries: jurisdictional boundaries, geography/topography, meteorology (coll ectively referred to as nature of the region), emission data, and air quality data. Additional dispersion modeling results will be provided to the U.S. EPA later this year to further support the attainment designation recommendation.

Nature of the Region

The Mojave Desert comprises portions of four counti es: eastern Kern County, northeast Los Angeles County, eastern Riverside County, and a ll but a small southwestern portion of San Bernardino County. Although the region is a djacent to the South Coast, California’s largest metropolitan area, the Mojave Desert is sparsely populated, with only 2.4% of the State population. Four local agen cies have jurisdiction over air quality in the Mojave Desert. Eastern Kern Air Pollution C ontrol District (APCD) governs the Kern County portion of the region. South Coast Air Quality Management District (AQMD) governs the Coachella Valley portion of Rive rside County, which adjoins the South Coast. The far eastern portion of Riverside County and the San Bernardino County portion of the Mojave Desert are governed by the Mojave Desert AQMD. Finally, the Antelope Valley AQMD has jurisdiction over the Los Angeles County portion of the region; however, they contract with the Moja ve Desert AQMD for the day-to-day operations in this area.

The Mojave Desert covers a total of 27,287 square m iles and is California’s largest air basin. The region is bounded by the Colorado R iver Valley to the south and east and by mountains on its remaining sides. The lands cape is quite diverse, including low elevation desert, high elevation desert, and mo untain areas. Elevations range from below sea level on the desert floor to peaks o f more than 7,000 feet. There are several scattered population centers, although the most heavily populated is the
Palmdale/Lancaster area. These two communities are located closest to the South Coast and have grown over the last several decades as bedroom communities of the South Coast. Major thoroughfares, including Inters tate 15, Interstate 40, U.S. Highway 395, and California State Highway 58, carry signifi cant amounts of commuter and truck traffic in and out of the Mojave Desert region.

### A-27

Overall, the Mojave Desert has an arid climate with cool winters, hot summers, and little rainfall. Temperatures generally increase, while p recipitation generally decreases from south to north and west to east in this region. Fo r example, the average minimum temperature in Palmdale is 48 degrees Fahrenheit (F ), while it is 61 degrees F in Needles. Similarly, the average maximum temperatur e in Palmdale is 81 degrees F, compared with 87 degrees F in Needles. Daily maxim um temperatures in both cities can top 100 degrees F during Summer, and annual ave rage rainfall is less than 8 inches. In contrast to the desert portions of th e region, both temperature and precipitation can be significantly different in the mountain areas, where snowcapped peaks are commonplace during Winter. Overall, the Mojave Desert tends to be windy, with winds blowing predominantly from the south and west. During the late spring months, high winds from the coastal areas of southe rn California blow into the Mojave Desert. In contrast, during Fall Santa Ana conditi ons, hot air from the desert blows into
southern California.

Emissions

The Air Resources Board’s (ARB) 2008 emission inven tory shows the Mojave Desert Air Basin with a total of 3,259 tons per year of SO x emissions. The largest source category is mineral processes, which comprises abou t 60% of the SO x emissions total. Cogeneration, electric utilities, aircraft, and tra ins are the next largest contributing categories, together accounting for another 20% of the inventory. The remaining SO x emissions are attributable to a number of smaller a rea-wide, on-road, and off-road

sources.

Although the numbers above reflect the total SO x inventory for the Mojave Desert, stationary sources are of particular interest with respect to the federal 1-hour SO 2 standard. Figure 11 shows the change in stationary source SO x emissions for the Mojave Desert between 1998 and 2008. The data refl ect sources in ARB’s facility emissions database. As shown in Figure 11, station ary source SO x emissions decreased about 5%, from 2,063 tons per year in 199 8 to 1,990 tons per year in 2008. The remainder of this discussion is focused on larg e stationary sources because implementation of the federal 1-hour SO 2 standard is focused on determining whether large sources cause violations. U.S. EPA guidance suggests initial focus on sources emitting more than 100 tons of SO x per year.

### A-28 FIGURE 11

Within the Mojave Desert, four facilities have emis sions exceeding 100 tons per year. A number of smaller sources are widely distributed th roughout the region. Figure 12 shows the relative locations of the four large faci lities, while Table 7 provides a summary of their city/county location and 2008 leve l of SO x emissions.

Two of the facilities, Mitsubishi Cement Company an d California Portland Cement Company, manufacture, process, and distribute Portl and cement. Cement manufacturing utilizes a mixture of raw materials s uch as limestone, clay, sand, and iron ore. These raw materials are ground and heated in a rotary kiln to produce “clinker.” After being cooled, the clinker is ground and then mixed with a small amount of gypsum to produce concrete. Most of the SO x emissions from this process result from the heating of the raw materials, with burning of fuels being a small contributing factor.

The third facility in the Mojave Desert, Searles Va lley Minerals, is a mining operation
that uses a solvent extraction method to recover bo ric acid from weak Searle’s Lake brines, thus providing a variety of Boron minerals. The last of the four facilities is the Ace Cogeneration Company. Cogeneration is the prac tice of operating a boiler to produce steam that provides heat for industrial pro cesses, as well as generates electricity. This facility uses a circulating flui dized bed combustion boiler, which reduces
the amount of sulfur emitted.

0 500 1,000 1,500 2,000 2,500

MDEmissions (t/y) 

### Sulfur Oxides Emissions from ARB's Facilities

Database - Mojave Desert Air Basin

1998 SOx (t/y) 2008 SOx (t/y)

### A-29 FIGURE 12

TABLE 7 Mojave Desert Facilities with SO x Emissions Greater than 100 Tons per Year

Facility Name City County SOx Emissions
California Portland Cement Company Mojave Kern 966 t/y

Mitsubishi Cement Lucerne Valley San Bernardino 256 t/y
Ace Cogeneration Company Trona San Bernardino 256 t /y
Searles Valley Minerals Trona San Bernardino 134 t/ y

### A-30

Sulfur oxide emissions from the four large faciliti es located in San Bernardino and Kern counties are controlled through a combination of lo cal district rules and permit conditions. Facilities in San Bernardino County co mply with the Mojave Desert AQMD’s Rule 406, which limits SO 2 emissions to 500 parts per million. The facility in Kern County complies with Eastern Kern APCD’s Rule 407. Under Rule 407, SO x emissions must not exceed a specified concentration limit at the point of discharge. This concentration limit is 0.2 percent by volume, calcu lated as SO 2

.

In addition to these local rules, U.S. EPA recently amended two rules that apply specifically to Portland cement manufacturing and w ill significantly reduce SO 2 emissions from these sources. The rules apply to b oth large and small, new and existing, cement kilns. Existing kilns, including those in the Mojave Desert, are required to comply in 2013. When fully implemented, U.S. EP A estimates a 78% percent
reduction in SO 2 emissions from affected cement kilns.

Air Quality Trends

Figures 13 and 14 show 1-hour SO 2 design value trends for two locations with long-te rm data: Trona and Victorville. The trend for Trona (refer to Figure 13) shows a decrease in design value from 1990 to 1995 at the Trona-Mark et Street site. There is a gap in the data record between 1995 and 2000, as the site was moved, and data collected at the interim site are not complete enough to calculate a representative design value. The interim site was moved to the Trona-Athol & Telegra ph location during 1997, and a representative three-year design value is available for 2000 and subsequent years. As shown on the graph, the design value for the Trona- Athol & Telegraph site continued the trend seen at the Trona-Market Street site, and the design value for the Trona area continues to hover around 10 ppb. The location of the monitoring site in the town of Victorville has also changed over time. Similar to the trend for Trona, the transition from the Victorville-Armagosa site to the Victorville-Pa rk Avenue is also smooth, with both sites showing design values well below the standard over the entire 20-year trend period (refer to Figure 14).

The current monitors in both Trona and Victorville are located near two of the Mojave
Desert facilities that have SO x emissions in excess of 100 tons per year and are s ited to capture high SO 2 concentrations. Based on data collected during 20 07 through 2009,
the 1-hour SO 2 design values for these sites are 10 ppb and 6 ppb , both of which are well below the level of the 75 ppb standard. These data demonstrate that SO 2 concentrations in the Mojave Desert attain the fede ral 1-hour SO 2 standard.

### A-31 FIGURE 13

FIGURE 14 0 10 20 30 40 50 60 70 80

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008Federal 1-hour SO2 (ppb) 

### 1-Hour Federal SO2 Design Value Mojave Desert - Trona

Trona-Market Street Trona-Athol & Telegraph Fed 1-hr SO2 NAAQS (75 ppb)

0 10 20 30 40 50 60 70 80

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008Federal 1-hour SO2 (ppb) 

### 1-Hour Federal SO2 Design Value

Mojave Desert - Victorville

Victorville-Armagosa Road Victorville-14306 Park Avenue Fed 1-hr SO2 NAAQS (75 ppb)

### A-32

Summary

Staff evaluated the five factors recommended by U.S . EPA for the purposes of determining attainment status and appropriate bound aries for federal SO 2 designations: jurisdictional boundaries, geography/topography, me teorology, emission data, and air quality data. Based on this analysis, violations o f the federal 1-hour SO 2 standard have not been measured over the last two decades, and vi olations are not expected to occur in the future. Therefore, staff recommends the Moj ave Desert be designated as attainment with the Mojave Desert Air Basin serving as the appropriate boundary for the
attainment area. This recommendation is based on t he following weight of evidence:

• There are two air quality monitors in the Mojave D esert, located in areas with high expected SO 2 concentrations. One-hour SO 2 design values for both
monitors are well below the level of the federal st andard;

• There are no geographical, topographic, or meteoro logical factors that warrant a different boundary for the attainment area.

• Large stationary sources in the Mojave Desert comp ly with local rules that limit SOx emissions, based on SO 2 concentrations;

• Recent revisions to U.S. EPA rules for Portland ce ment manufacturers will significantly reduce emissions from cement kilns. Existing kilns, such as those in the Mojave Desert, must comply by 2013;

• Dispersion modeling results for large SO 2 emission facilities in the Mojave Desert will be provided to the U.S. EPA later this year to further support the attainment designation.

### A-33

V. SOUTH CENTRAL COAST AIR BASIN

Recommendation

Ambient air quality monitors in the South Central C oast Air Basin (South Central Coast or SCC) show a 2009 1-hour sulfur dioxide (SO 2 ) design value of 35 parts per billion (ppb), which is well below the level of the federal standard. Based on the following assessment, staff recommends the South Ce ntral Coast be designated as
attainment. The assessment includes an evaluation of the five factors recommended by U.S. EPA for the purposes of determining the approp riate attainment area boundaries: jurisdictional boundaries, geography/topography, an d meteorology (collectively referred to as nature of the region), emission data, and air quality data. Dispersion modeling results will be provided to the U.S. EPA later this year as additional support for the attainment designation recommendation.

Nature of the Region

The South Central Coast comprises all of San Luis O bispo, Santa Barbara, and Ventura counties. Overall, the region covers 7,887 square miles and is home to approximately 4% of California’s population. More than half the region’s population lives in Ventura County, and the largest cities include Oxnard, Thou sand Oaks, and Ventura. Each of the three counties in the South Central Coast is go verned by its own air pollution control district (APCD): the Ventura County APCD, the Sant a Barbara County APCD, and the San Luis Obispo County APCD. These agencies have r esponsibility for developing and implementing rules and regulations to control SO x emissions from stationary sources located in their local county area.

The region is bounded by the Pacific Ocean on the w est and south, and it includes six of the eight Channel Islands. All three counties c omprise a relatively narrow coastal strip that gives way to inland mountains, with the highest elevations ranging from 6,000 to over 8,000 feet. San Luis Obispo County, the no rthernmost county, covers 3,304 square miles. The County is more rural and a gricultural than many of California’s other coastal regions, with a number of small commu nities scattered along the beaches, coastal hills, and mountains. Santa Barbara County is the middle county, comprising 2,737 square miles. In addition to the mainland ar ea, the County includes Santa Cruz, San Miguel, Santa Rosa, and Santa Barbara islands. Similar to San Luis Obispo County, most Santa Barbara County residents live in or near the coastal area. Ventura County, which includes Anacapa and San Nicolas isla nds, is the most populated county
in the South Central Coast. It is also the smalles t, with an area of 1,845 square miles. Significant population centers are found along Vent ura County’s coastline (Oxnard and Ventura), as well as inland (Simi Valley and Thousa nd Oaks).

### A-34

In terms of climate, the South Central Coast genera lly has relatively wet winters and warm dry summers. Coastal areas benefit from the m arine influence, where onshore breezes keep beach communities cooler in summer and warmer in winter than
communities located further inland. Year-round tem peratures near the coast are mild, with average minimums in the 40s and 50s and averag e maximums in the 60s and low 70s. Average precipitation in this part of the reg ion is between about 15 and 25 inches per year. In contrast, the inland areas are warmer and dryer. In these areas, average minimum temperatures are still in the 40s and 50s. However, average maximums can be in the high 70s, and daily summer maximums can e xceed 100 degrees Fahrenheit. Rainfall totals in the inland portions of the South Central Coast are generally less than 15 inches per year.

Emissions

Based on the Air Resources Board’s (ARB) 2008 emiss ion inventory, there were 4,646 tons of SO x

emissions in the South Central Coast Air Basin. T wo major source categories account for the majority of these emissi ons: petroleum refining operations (close to 60%) and mineral processes (about 30%). More than 90% of the SO x emissions within the mineral processes source categ ory are attributable to diatomaceous earth processing.

The remainder of this discussion is focused on larg e stationary sources because implementation of the federal 1-hour SO 2 standard is focused on determining whether large stationary sources are likely to cause violat ions of the standard. U.S. EPA guidance suggests initial focus on sources emitting more than 100 tons of SO x per year. Similar to other areas of California, most of the S O x emissions in the South Central Coast come from stationary sources. As shown in Fi gure 15, which is based on ARB’s facility emissions database, emissions from station ary sources decreased more than
70% between 1998 and 2008.

Facility SO x

emissions were reduced even further in 2010, from a combination of more stringent rules and permit requirements, along with the implementation of federal consent decrees. There are two large SO x stationary sources in the South Central Coast (refer to Figure 16). These sources are the Conoco Phillips Santa Maria Refinery in San Luis Obispo County and the Celite Corporatio n, a facility in Santa Barbara County that processes diatomaceous earth. Both are discussed in more detail, below.
SO x emissions from the remaining stationary sources in the South Central Coast are below 100 tons per year, with each emitting between 0 and 30 tons of SO x per year.

### A-35 FIGURE 15

FIGURE 16 0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000 20,000Emissions (t/y) Sulfur Oxides Emissions from ARB's

Facilities Database - South Central Coast

1998 SOx (t/y) 2008 SOx (t/y)

### A-36

Conoco Phillips Facility: The Conoco Phillips Santa Maria Refinery (Conoco Ph illips SMR or SMR) facility is located near the town of Ni pomo in San Luis Obispo County. The SMR facility was originally built by Union Oil Company of California in 1955 and has had several owners since then, including Tosco, Phi llips Petroleum, and now Conoco Phillips. The refinery operates 24 hours per day, y ear-round, unless operations are shut down for maintenance. Over time, the San Luis Obis po County APCD has been successful in securing substantial emission reducti ons from this facility not just for SO x , but also for reactive organic gases and particulate matter.

The estimated SO x

emissions from this facility have decreased nearly 95% since 2006 – emissions were 2,668 tons per year in 2006 compare d with only 154 tons per year in 2010. These are verifiable reductions, attributabl e to emission control measures adopted by the San Luis Obispo County APCD and to c ompliance with a recent U.S. EPA consent decree. Of particular importance is th e recent shutdown of the calciner
kiln stack.

When it was operating, the calciner unit accounted for over 90% of SO x emissions in San Luis Obispo County and almost 95% of the annual SO 2 emissions from the entire SMR facility (refer to Table 8, below). On May 31, 2006, the San Luis Obispo County APCD Board took action and approved amendments to D istrict Rule 440, Petroleum Coke Calcining and Storage Operations. This Rule r equired an 80% reduction in SO 2 emissions from SMR coke calcining operations and li mits the storage of green coke to the levels that were stored at the facility as of J anuary 1, 2006. On March 13, 2007, Conoco Phillips SMR shut down the calciner unit. O nly green petroleum coke is generated by the coker units, stored in greatly red uced storage piles, and shipped out. As shown in Table 8, total emissions from the SMR f acility have been greatly reduced since 2006, but there is some year-to-year variatio n. This variation is attributable to year-to-year differences in feedstock and throughpu t.

TABLE 8

SO 2 Emission History at Conoco Phillips Santa Maria Re finery

Calendar Year Total SMR Facility SO 2 Calciner Unit SO 2 2006 2668 tons/year 2500 tons/year 2007 789 tons/year 668 tons/year 2008 176 tons/year 0 2009 129 tons/year 0 2010 154 tons/year 0

### A-37

Other relevant measures contributing to the SO x emission reductions at the SMR facility
are summarized below:

• U.S. EPA Consent Decree: As part of U.S. EPA's on-going multi-company Refinery Initiative, SMR was issued a Consent Decre e in 2004/2005 covering both emission reductions and procedural changes und er various regulatory compliance requirements, including New Source Perfo rmance Standards (NSPS)
and National Emissions Standards for Hazardous Air Pollutants (NESHAP). The San Luis Obispo County APCD and U.S. EPA partnered in writing and implementing the Consent Decree. SMR is still oper ating under this Consent Decree, working towards full compliance with its pr ovisions. December 2011 and 2013 mark upcoming milestone deadlines.

• Abatement Order:

In 1989, the San Luis Obispo County APCD issued a n Abatement Order for the SMR facility, addressing nu merous neighborhood odor complaints and excessive emissions from operations at the refinery and carbon plant. The Abatement Order included conditions for new and modified emission controls, odor abatement projects, new monitoring e quipment, and procedural changes. Odor complaints, which numbered over 350 during the year prior to the Abatement Order, are now sporadic and usually in co njunction with facility upset conditions. The San Luis Obispo County APCD consid ers the Abatement Order a success in curbing emissions and odors from proce sses at the SMR facility.

Celite Corporation: Celite Corporation is a diatomaceous earth process ing plant located in the city of Lompoc in Santa Barbara Coun ty. In the recent past, SO x emissions from the Celite facility exceeded 700 ton s per year. Since then, Celite Corporation has permanently ceased operating two ol der processing lines. They recently installed a new processing line that inclu des SO x emission control equipment with a potential to emit restriction of 13 tons per year. The new processing line includes Best Available Control Technology (BACT), comprisin g a high energy venturi scrubber and packed bed scrubber combination SO x control unit. The Authority to Construct (ATC) permit contains specific SO x emission limitations, reflecting BACT control.

The plant is currently going through a shake-out pe riod under the ATC permit, and the new processing line limits reflecting BACT cont rol will ultimately be federally enforceable under a Part 70 permit. One older line is being retained by Celite Corporation as a back-up, anticipated to operate fo r only brief periods if the new line breaks down. As a result, hourly SO x emissions will routinely be under 3 pounds/hour, consistent with the permit limitations. The Santa Barbara County APCD has provided a
recent source test that demonstrates the SO x control equipment is meeting the required efficiency and SO x

emissions are in compliance with the permit limits . Because

### A-38

SO x emissions are now under 100 tons per year, the Cel ite Corporation facility will not require modeling.

Air Quality Trends

The South Central Coast has an extensive air qualit y monitoring network, including a number of monitors that collect quality-assured SO 2 data for record. Several of these
monitors are located near the two SO x facilities described above and therefore reflect high SO 2 concentrations within the South Central Coast regi on. In addition, several other monitors are located along the coast, downwin d of these facilities. These downwind sites monitor public exposure from smaller facilities and area-wide SO x emissions from transportation sources (refer to Fig ure 16 for relevant monitor locations). Based on data for record, the South Central Coast a ttains the federal 1-hour SO 2 standard, with 2009 design values ranging from 2 pp b to 35 ppb, which is well below the
level of the federal standard.

The highest design value is for the Nipomo-Guadalup e Road monitoring site, located near the Conoco Phillips SMR. The long-term design value for the Nipomo site is plotted in Figure 17. It shows a significant reduc tion between 2006 and 2009. As shown in Table 8, the SMR facility sharply reduced emissions from its calciner unit between 2006 and 2007. The facility then shut the calciner unit down, in March 2007. The design value at Nipomo reflects these emission reductions, dropping more than 50% between 2006 and 2009 (from 86 ppb to 35 ppb). Design values for future years should be even lower, because the 2009 design value still includes data for 2007 and 2008, before the calciner unit ceased operating. M aximum 1-hour SO 2 concentrations provide a good illustration of the significant decr ease in SO 2 concentrations over the three-year period, with maximums of 151 ppb in 2007 , 47 ppb in 2008, and 17 ppb in
2009.

In addition to Nipomo, Figure 17 also shows the lon g-term trend for the monitoring site nearest the Celite facility (Lompoc-South H Street) . The 2009 design value for this site is 6 ppb, less than one-tenth the level of the fede ral standard. It should be noted that the three-year period reflected in this design valu e (2006-2009) includes a period of uncontrolled high emissions at the Celite facility. Even so, the design value does not violate the standard. The remaining trend plotted in Figure 17 reflects the downwind coastal site with the highest 2009 design value – L as Flores Canyon-#1, in Santa Barbara County. The design value for this site is also well below the level of the federal standard, at 6 ppb. Based on these data and data f or other sites in the region,
violations of the federal 1-hour SO 2 standard are unlikely in the South Central Coast.

### A-39 FIGURE 17

Summary

Staff evaluated the five factors recommended by U.S . EPA for the purposes of determining appropriate attainment status and bound aries for federal SO 2 designations: jurisdictional boundaries, geography/topography, me teorology, emission data, and air quality data. This five factor analysis shows that violations of the federal 1-hour SO 2 standard have not been measured over the last sever al years, and because of
substantial verifiable and enforceable emission red uction measures, are not expected to occur in the future. Therefore, staff recommends t he South Central Coast be designated as attainment, with the South Central Co ast Air Basin serving as the appropriate boundary for the attainment area. This recommendation is based on the following weight of evidence:

• The South Central Coast has a comprehensive SO 2 monitoring network, with monitoring sites located in areas with the highest SO x emissions and highest expected SO 2 concentrations;

• 2009 design values for all sites in the South Cent ral Coast region are well below the standard, including values for sites nearest th e Conoco Phillips SMR and 0 20 40 60 80 100 120 140Federal 1-hour SO2 (ppb) 1-Hour Federal SO2 Design Values
South Central Coast

Nipomo-Guadalupe Road Lompoc-S H Street Las Flores Canyon #1 Fed 1-hr SO2 NAAQS (75 ppb)

### A-40

Celite Corporation facilities. The highest 2009 de sign value in the region was 35 ppb, less than half the level of the federal 1-h our SO 2 standard;

• Emissions from SO x facilities in the South Central Coast decreased 30 %
between 1998 and 2008.

• Since 2006, SO x

emissions from the Conoco Phillips SMR facility ha ve decreased close to 95%, from 2,668 tons per year to 154 tons per year;

• SO x emissions are expected to decrease from 743 tons p er year to 13 tons per year at the Celite Corporation in Santa Barbara Cou nty, once their permit to operate is finalized. Therefore, this facility wil l not require modeling;

• There are no significant differences in geography, topography, or meteorology in
the South Central Coast that warrant an attainment area boundary different from the Air Basin boundary;

• Dispersion modeling results for the Conoco Phillip s SMR facility will be provided to the U.S. EPA later this year, to further support the attainment designation;

• Staff will work with the Santa Barbara APCD to upd ate their emissions inventory, after the Celite Corporation’s final permit to oper ate has been issued and is fully implemented.

### A-41

VI. REMAINING AIR BASINS

Recommendation

The staff recommends that the following areas be de signated as attainment, based on the assessment provided below. The assessment incl udes an evaluation of the five factors recommended by U.S. EPA for purposes of det ermining the appropriate attainment area boundaries: air quality data, emiss ions data, meteorology, geography/topography, and jurisdictional boundaries

. Staff recommends that air basins be used as the jur isdictional boundaries for the
attainment areas. In some cases air basins consist of a single air district, but the majority of air basins are composed of one or more air districts, each containing one or more counties or portions of counties. Air basins were determined based on similar meteorology and geography of the area which they co ntain.

The following air basins, and the counties included within, contain no large stationary
sources of SO x

emissions.

Air Basin Counties Sacramento Valley Butte, Colusa, Glenn, Sacramento, Shasta, Sutter, Tehama, Yolo, Yuba, western Placer, northeastern
Solano San Diego San Diego Salton Sea Imperial, central Riverside North Central Coast Santa Cruz, San Benito, Montere y North Coast Del Norte, Humboldt, Trinity, Mendocino , northern
Sonoma Mountain Counties Plumas, Sierra, Nevada, central P lacer, western El Dorado, Amador, Calaveras, Tuolumne, Mariposa Great Basin Valleys Inyo, Mono, Alpine Lake County Lake
Lake Tahoe Portions of El Dorado and Placer Northeast Plateau Lassen, Modoc, Siskiyou

In general, these air basins encompass regions of t he state that are more rural in nature. Population tends to be concentrated in a s mall number of urban areas, most notably Sacramento and San Diego Counties. There a re no facilities located in these air basins with significant SO x emissions (greater than 100 tons per year), and in comparison to the rest of the state, total SO x emissions are low. SO 2 monitoring data is available only in select areas where the highest SO 2 concentrations are expected to

### A-42

occur, and concentrations at these monitors are far below the standard. These monitors are located in the areas with the largest emissions. Since the existing monitoring network indicates that all areas are wel l below the level of the standard, we
conclude that areas without monitors would also be considerably below the standard.

Sacramento Valley Air Basin

Nature of the Region

The Sacramento Valley Air Basin (SVAB) is located i n the northern portion of the Central Valley. It includes Butte, Colusa, Glenn, Sacramento, Shasta, Sutter, Tehama, Yolo, and Yuba Counties, the western urbanized port ion of Placer County, and the northeastern portion of Solano County. The SVAB oc cupies nearly 15,000 square miles and has a population of more than 2.5 million peopl e. More than half of the total population in the eleven-county air basin resides i n Sacramento County.

The SVAB is approximately 216 miles from north to s outh and 95 miles east to west at the widest part. It is bounded on the north and we st by the Coast Range Mountains and on the east by the southern portion of the Cascade Mountain Range and the northern portion of the Sierra Nevada Mountains. Within the SVAB the elevations reach heights of approximately 3,500 feet in the southwest, 8,500 feet in the northwest, 1,700 feet in the southeast and 10,500 feet in the northeast. In contrast, the elevation in Sacramento County near the San Francisco Bay delta is barely a bove sea level. The mountain ranges provide a significant physical barrier to tr ap locally created pollution as well as pollution transported into the SVAB from elsewhere.

The Sacramento Valley’s usual summer daytime wind f low pattern is characterized by onshore flow from the Bay Area to Sacramento (known as the sea breeze). A portion of the wind flow turns south, blowing into the San Joa quin Valley, a portion continues eastward, across the southern Sacramento Valley, an d a portion turns north, blowing into the upper Sacramento Valley. At night, the se a breeze weakens, and the wind direction in the Sacramento Valley changes. Typica l downslope flow, known as nocturnal drainage, brings air from the Coast Range and Sierra Nevada Mountains into the Sacramento Valley.

### A-43 FIGURE 18

Emissions

There are no facilities in the SVAB with SO x emissions greater than 100 tons per year. In 1998, the total facility SO x emissions were 595 tpy. By 2008, the facility SO x emissions dropped to 410 tpy, a decrease of over 30 %. Other sources of SO x emissions in SVAB are of a more diffuse nature, suc h as residential burning, managed burning, trains, airplanes, and vehicles. Emission s from all sources totaled 1,240 tpy in 2008, down from over 2,300 tpy in 1998, a 45% reduc tion.

Air Quality Trends

Based on quality-assured data for record, the SVAB attains the revised federal SO 2 standard, with a 2009 design value of 4 ppb. The S VAB has monitoring data available from five sites, one in Butte County and four in Sa cramento County. The monitor in Butte County was located at Chico-Manzanita Avenue and operated from 1981 to 1984.
SO 2 concentrations were very low, and never came close to the level of the revised standard (75 ppb). Monitors in Sacramento County i nclude Citrus Heights-Sunrise Boulevard (1980-1983), Sacramento-P Street (1980-19 82), Sacramento-Del Paso

### A-44

Manor (1980-present), and North Highlands-Blackfoot Way (1980-2010). Monitors are
located in areas of the air basin where we would ex pect the highest SO 2 concentrations to occur. These are also the areas with the greate st population density, capturing emissions from area-wide sources, such as residenti al burning and vehicles, as well as stationary facility sources. As shown in Figure 19 below, design values have been steadily decreasing since 2000. The 2009 design va lue is just 4 ppb, down from 20 ppb in 2001. Since monitoring began in 1980, SO 2 concentrations have been well below the
level of the revised standard.

FIGURE 19

Sacramento Valley Air Basin SO 2 1-Hour Design Values

San Diego Air Basin

Nature of the Region

The San Diego Air Basin (SDAB) lies in the southwes t corner of California and comprises the entire San Diego region. Population is concentrated mainly in the western portion of the county. The air basin cover s 4,260 square miles, and is home to over three million residents. The City of San Dieg o covers approximately 330 square miles, and has a population of over 1.3 million, 42 percent of the total population of San Diego County.

The topography in SDAB varies greatly, from beaches on the west to mountains and desert on the east. Much of the topography in betw een consists of mesa tops intersected by canyon areas. Topography, along wit h local meteorology, influences the

0 10 20 30 40 50 60 70 80

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

North Highlands-Blackfoot Way Sacramento-Del Paso Manor

### A-45

dispersal and movement of pollutants in the basin. The mountains to the east prohibit dispersal of pollutants and help trap them under in version layers.

The San Diego region typically has dry, warm summer s and mild, occasionally wet winters. The average temperature ranges from the m id 40s to the high 90s. Most of the county’s precipitation falls from November to April , with infrequent precipitation during the summer. The average seasonal precipitation alo ng the coast is approximately
ten inches.

FIGURE 20

Emissions

There are no facilities located in the SDAB that ha ve emissions greater than 100 tons per year. Emissions from all facilities in SDAB to taled just 85 tpy in 2008. The largest
sources of SO x

emissions in SDAB are more regional, including tra ins, shipping ports, fuel combustion and residential burning. Total SO x emissions from all sources totaled 730 tpy in 2008, down from 1030 tpy in 1998, a redu ction of nearly 30%.

### A-46

0 10 20 30 40 50 60 70 8019901991199219931994199519961997199819992000200120022003200420052006200720082009

Chula Vista Otay Mesa-Paseo International San Diego-1110 Beardsley Street San Diego-12th Avenue Air Quality Trends

Based on data for record, the SDAB attains the revi sed federal SO 2 standard, with a valid 2009 design value of 17 ppb. The design valu e at Otay Mesa (22 ppb) is not
considered valid under U.S. EPA criteria. SDAB has had several monitors operating at various times from 1980 to the present. Currently, there are three sites with SO 2 monitors – San Diego-Beardsley Street, Otay Mesa-Pa seo International, and Chula Vista. Otay Mesa and Chula Vista have long term da ta dating back to the early 1990s. Only Chula Vista has come close to the level of the revised standard in 1994 when the design value reached 72 ppb. However, emissions ha ve dropped dramatically since then. The 2009 design value at Otay Mesa is just 2 2 ppb, 7 ppb at Chula Vista, 17 ppb at San Diego – Beardsley Street.

The monitor at Otay Mesa is located near the Califo rnia/Mexico border and captures
emissions from international commerce. The monitor s in Chula Vista and downtown San Diego are designed to measure community exposur e. The three monitors are located in areas where the highest SO 2 concentrations are expected to occur.

FIGURE 21 San Diego Air Basin SO 2 1-hour Design Values

### A-47

Salton Sea Air Basin

Nature of the Region

The Salton Sea Air Basin (SSAB) is composed of the central portion of Riverside County (Coachella Valley) and Imperial County. The Coachella Valley extends
southeast from the San Bernardino Mountains to the Salton Sea, the largest saltwater lake in California. The Riverside County portion o f the SSAB is separated from the South Coast Air Basin on the west by the San Jacint o Mountains and the Santa Rosa Mountains and from the Mojave Desert Air Basin to t he east by the Little San Bernardino Mountains. Imperial County borders Mexi co to the south. The SSAB has a population of approximately 650,000.

The mountain peaks range from 3,000 to 11,000 feet in elevation, and prevent off-shore winds from flowing into the Coachella Valley and Im perial County. During the summer, high temperatures in the SSAB frequently exceed 100 degrees Fahrenheit. In the winter, daytime temperatures are generally over 70 degrees. The SSAB averages between three and seven inches of precipitation per year.

FIGURE 22

### A-48

Emissions

There are no facilities located in the Salton Sea A ir Basin with SO x emissions greater than 100 tons per year. The largest facility in th e basin is the Palm Springs International Airport. Emissions from all facilities combined to taled 124 tpy in 2008. All other sources of emissions in the SSAB totaled 270 tpy in 2008, down from 590 tpy in 1998, a reduction of over 50 percent. The largest SO x sources are trains, fuel combustion and residential burning.

Air Quality Trends

Based on data for record, the Salton Sea Air Basin attains the revised federal SO 2 standard, with a 2009 design value of 10 ppb. Curr ent monitoring is conducted at the Imperial Calexico site. Historic data is also avai lable from the Riverside-Palm Springs
Fire Station. No monitor in the SSAB has ever come close to the level of the standard since monitoring began in 1980.

FIGURE 23

Salton Sea Air Basin SO 2 1-hour Design Values

North Central Coast Air Basin

Nature of the Region

The North Central Coast Air Basin (NCCAB) consists of Santa Cruz, San Benito, and Monterey Counties. It covers an area of 5,159 squa re miles along the coast, and has a

0 10 20 30 40 50 60 70 801994199519961997199819992000200120022003200420052006200720082009

Imperial Calexico-East Imperial Calexico-Ethel Street

### A-49

population of over 750,000. The Santa Cruz Mountai ns dominate the northwest portion of NCCAB, and the Diablo Range marks the northeaste rn boundary. The Santa Clara Valley extends into the northeastern tip of the bas in. Further south, the Santa Clara Valley becomes the San Benito Valley, which runs no rthwest-southeast, with the Gabilan Range as its western boundary. To the west of the Gabilan Range is the Salinas Valley, which extends from Salinas at the n orthwest end to south of King City.

In the summer, a high-pressure system over the Paci fic Ocean is dominant and causes persistent west and northwest winds over the entire California coast. The onshore wind brings fog and relatively cool air into the coastal valleys. The northwest-southeast orientation of the mountain ridges tends to restric t and channel the summer onshore air. In the fall, the surface winds become weak. The ai rflow is occasionally reversed in a weak offshore movement and the relatively stationar y air mass is held in place. During the winter, the Pacific high-pressure system moves south and has less influence on the NCCAB. Air frequently flows in a southeasterly dir ection out of the Salinas and San Benito Valleys, especially during night and morning hours.

FIGURE 24

### A-50

Emissions

As of 2009, there are no facilities in the NCCAB wi th SO x emissions greater than 100 tons per year. Prior to 2009, the Cemex Cement Plant, operated in Davenport, had
SO x emissions of 179 tpy. The Cemex Cement Plant clos ed at the end of 2008, and the permit to operate was forfeited. In 2008, SO x emissions from all facilities totaled 261 tpy. In 2009, the total emissions dropped to j ust 69 tpy, due to the closure of the Cemex facility. SO x

emissions from all sources in NCCAB totaled 908 tp y in 2008, down from 967 tpy in 1998, a 6% reduction.

Air Quality Trends

Based on available data for record from 2007 to Sep tember 2009, the NCCAB attains
the revised federal SO 2 standard with a design value of 11 ppb. The air b asin had only
one SO 2 monitor in operation, located in the town of Daven port. After the closure of the Cemex Cement Plant, the Davenport monitor was shut down at the end of September 2009. The design value is not considered complete under U.S. EPA criteria because data from October through December 2009 are missing . However, even with the Cemex Plant in operation, design values were genera lly in the 10 – 20 ppb range over a period of 20 years, never exceeding 30 ppb. With t he closure of the Cemex Plant, we expect the design value will remain well below the level of the revised standard.

FIGURE 25
North Central Coast SO 2 1-hour Design Values

0 10 20 30 40 50 60 70 8019901991199219931994199519961997199819992000200120022003200420052006200720082009SO2 concentrations (ppb)

Davenport

### A-51

North Coast Air Basin

Nature of the Region

The North Coast Air Basin (NCAB) includes the count ies of Del Norte, Humboldt, Trinity, Mendocino, and the northern portion of Sonoma Count y. It has a land area of more than 12,000 square miles, and a population of appro ximately 330,000.

In general, the climate of the North Coast is chara cterized by cool summers with frequent fog and mild winters with lots of rain. I n coastal areas, the ocean helps to moderate temperatures year-round. Further inland, the summers are hotter and drier and the winters colder and more snowy. At higher e levations in inland areas, it is cooler
in the summers and snowier in the winter. In the s ummer months strong northwesterly winds are common. During the winter, storms from t he south Pacific lead to winds from
the south.

FIGURE 26

### A-52

Emissions

There are no facilities in the NCAB with SO x emissions greater than 100 tons per year.
Emissions from all facilities in NCAB totaled 140 t py in 2008. SO x emissions from all sources in NCAB totaled 558 tpy in 2008, down from 615 tpy in 1998, a reduction of almost 10%. The largest sources of SO x emissions are residential burning and fuel
combustion.

Air Quality Trends

Based on data for record, the NCAB attains the revi sed federal SO 2 standard, with a 2009 design value of 5 ppb, down from 25 ppb in 200 6. Monitoring for SO 2 in the NCAB is currently conducted at the Eureka-Jacobs site. Historic data is available from EurekaFort Avenue from 1981-1983, Ukiah-Gobbi Street from 1992-1995, Ukiah-Highway 101 from 1988-1990, and Willits-S Main Street from 1994 -1996. Design values at these
sites have never been near the level of the revised standard. The highest design value in the NCAB was 30 ppb at the Ukiah-Highway 101 sit e in Mendocino in 1992.

FIGURE 27
North Coast 1-hour SO 2 Design Values

0 10 20 30 40 50 60 70 80

1990 1992 1993 1994 1995 1996 2006 2007 2008 2009

Mendocino Ukiah-E Gobbi Street Mendocino Willits-899 S Main Street Eureka-Jacobs

### A-53

Mountain Counties Air Basin

Nature of the Region

The Mountain Counties Air Basin (MCAB) includes Plu mas, Sierra, Nevada, Placer (middle portion), El Dorado (western portion), Amad or, Calaveras, Tuolumne, and Mariposa Counties. The basin lies along the northe rn Sierra Nevada Mountain Range, close to or contiguous with the Nevada border, and covers an area of roughly 11,000 square miles. The population of the entire air bas in is less than 500,000. The western slope of El Dorado County, from Lake Tahoe on the e ast to the Sacramento County boundary on the west, lies within the MCAB. Elevat ions range from over 10,000 feet at
the Sierra crest down to several hundred feet above sea level at the Sacramento County boundary. Throughout the basin, the topogra phy is highly variable, and includes rugged mountain peaks and valleys with extreme slop es and differences in elevation in the Sierras, as well as rolling foothills to the we st.

The general climate of the MCAB varies considerably with elevation and proximity to the Sierra ridge. The terrain features of the basin ma ke it possible for various climates to exist in relatively close proximity. The Sierra Ne vada receives large amounts of precipitation in the winter, with lighter amounts i n the summer. Precipitation levels are high in the highest mountain elevations but decline rapidly toward the western portion of the basin. Winter temperatures in the mountains ca n be below freezing for weeks at a time, and substantial depths of snow can accumulate , but in the western foothills, winter temperatures usually dip below freezing only at nig ht and precipitation is mixed as rain or light snow. In the summer, temperatures in the mountains are mild, with daytime peaks in the 70s to low 80s, but the western end of the basin can routinely exceed 100 degrees.

### A-54 FIGURE 28

Emissions

There are no facilities in the MCAB with SO x emissions greater than 100 tons per year.
Total SO x

emissions from all facilities totaled 162 tpy in 2 008. The largest contribution
to SO x emissions are from residential and managed burning , trains, and cogeneration plants. Total emissions in MCAB in 2008 were 858 t py, down from 1555 tpy in 1998, a
45% reduction.

Air Quality Trends

Currently, no SO 2 monitors exist in MCAB. One monitor, San Andreas- Gold Strike Road, operated from 1980-1982. The design value at that time was 10 ppb. Due to the
low SO x emissions throughout the MCAB, we conclude that th e area would not exceed
the level of the standard.

### A-55

Great Basin Valleys Air Basin

Nature of the Region

The Great Basin Valleys Air Basin (GBVAB) includes Inyo, Mono and Alpine Counties. This basin is bounded on the west by the Sierra Nev ada Mountains, on the east by the Nevada border, and on the south by the desert. As the transition from the Great Basin Valleys to the desert is somewhat indistinct, the I nyo-San Bernardino County line has been chosen as the basin boundary.

The population in the GBVAB is approximately 35,000 , approximately 2 people per square mile. Much of the land area is open desert. The land use varies from riparian areas along the Owens River to light industry, smal l commercial and residential in the City of Bishop (population 4,000). The topography varies from high desert to mountain peaks.

FIGURE 29

### A-56

Emissions

There are no facilities in the Great Basin Valleys Air Basin with SO x emissions greater than 100 tons per year. SO x emissions from all facilities in 2008 were just 32 tpy. The largest contributors of SO x emissions in GBVAB are managed burning and fuel
combustion. Emissions from all sources totaled 263 tpy in 2008, down from 375 tpy in 1998, a 30% reduction.

Air Quality Trends

There is no monitoring data available for GBVAB. H owever, due to the very low SO x emissions throughout the GBVAB, we conclude that th e area would not exceed the level
of the standard.

Lake County Air Basin

Nature of the Region

Lake County Air Basin (LCAB) consists of only Lake County. It is located inland from the Pacific Ocean, north of the San Francisco Bay A rea, covers an area of 1,327 square miles and has a population of nearly 65,000. The h ighest peak in LCAB is Snow Mountain at 7,056 feet in the wilderness area of th e Mendocino National Forest. LCAB has just two incorporated cities, Clearlake and Lak eport, surrounded by several smaller
communities.

FIGURE 30

### A-57

Emissions

There are no facilities in LCAB with SO x emissions greater than 100 tons per year. All facilities in LCAB combined emit just 34 tpy SO x in 2008. The largest contributors of
SO x emissions are agriculture production and processin g and residential burning. The
total emissions from all sources in LCAB were 153 t py in 2008, down from 168 tpy in 1998, a 9% reduction.

Air Quality Trends

There is no monitoring data available for LCAB. Ho wever, due to the very low SO x emissions throughout the LCAB, we conclude that the area would not exceed the level
of the standard.

Lake Tahoe Air Basin

Nature of the Region

The Lake Tahoe Air Basin (LTAB) is comprised of the surface of Lake Tahoe (roughly 20 miles long by 10 miles wide) and land up to the surrounding rim of mountain ridges. The southern portion of the air basin is in El Dora do County and the northern portion is in Placer County. The basin has a population of le ss than 60,000. The lake is at 6,200 feet elevation, and the ridges climb to over 10,000 feet. The mountain slopes surrounding the lake are quite precipitous, and are broken by deep valleys carved by
streams that drain into the lake.

The meteorology of the LTAB in winter is typified b y large amounts of precipitation from Pacific storms that fall mainly as snow, and temper atures below freezing accompanied by winds, cloudiness, and lake and valley fog. Win ter days can also bring cool, brilliantly clear days between storms. In the summ er, the LTAB experiences sunny, mild days, with daytime peaks in the upper 70s and low 80s, with an occasional
thunderstorm from southern flows of moisture.

### A-58 FIGURE 31

Emissions

There are no facilities in the Lake Tahoe Air Basin with SO x emissions greater than 100 tons per year. There are virtually no SO x facility emissions, just over 1 tpy in the entire basin. The largest contribution of SO x emissions is from residential burning and airplanes. In 2008, SO x emissions totaled 40 tpy, down from 44 tpy in 1998 , a 9%
reduction.

Air Quality Trends

There is no monitoring data available for LTAB. Ho wever, due to the very low SO x emissions throughout the LTAB, we conclude that the area would not exceed the level
of the standard.

### A-59

Northeast Plateau Air Basin

Nature of the Region

The Northeast Plateau Air Basin (NEPAB) is located in the northeast corner of California and includes Lassen, Modoc, and Siskiyou Counties. The northern part of NEPAB has lofty volcanic peaks, such as Mount Shast a and Mount Lassen. Forested mountains dominate the southern and western regions . The NEPAB covers approximately 14,788 square miles and is bordered b y the states of Oregon to the north and Nevada to the east. NEPAB’s population of near ly 95,000 predominately resides in rural towns, including Yreka, Mount Shasta, Alturas , and Susanville.

The climate is dry, cool, and windy. The area is s eparated from the rest of the State by the Cascade Mountains to a degree that permits very little air movement to or from other regions in the State.

FIGURE 32

### A-60

Emissions

There are no facilities in the NEPAB with SO x emissions greater than 100 tons per year. All facilities combined emitted just 45 tpy in 2008 . Emissions from all sources in NEPAB totaled 215 tpy in 2008, down from 533 tpy in 1998, a nearly 60% reduction. The largest sources of emissions are from trains and re sidential burning.

Air Quality Trends

There is no monitoring data available for NEPAB. H owever, due to the very low SO x emissions throughout the NEPAB, we conclude that th e area would not exceed the level
of the standard.

Summary

ARB staff has evaluated the five factors recommende d by U.S. EPA for purposes of determining the appropriate attainment status and b oundaries: air quality data, emissions data, meteorology, geography/topography, and jurisdictional boundaries. Based on this five factor analysis, the above menti oned air basins should be designated
as attainment areas for the federal 1- hour SO 2 standard. This recommendation is based on the following weight of evidence:

• There are no stationary source facilities in these areas with SO 2 emissions greater than 100 tons per year.

• ARB maintains a statewide monitoring network, with monitoring sites in the areas with the highest expected SO x emissions. All design values in areas with monitors are well below the standard; areas without monitors have significantly
lower SO x

emissions. Therefore, we conclude that areas with out monitors would
also attain the standard.

• Stringent statewide SO 2 control measures will reduce emissions from source s including diesel fuel, locomotives, and shipping.

• There are no specific meteorological or topographi cal factors which would
warrant different boundaries for the attainment are as.

# APPENDIX 2

2009 SO2 1-HOUR DESIGN VALUES FOR

ALL SITES IN CALIFORNIAThis page intentionally left blank.APPENDIX 2: 2009 SO2 1-Hour Federal Design Values 1

Basin County Site Name SO2 1-hr Fed DV (ppb)

Mojave Desert San Bernardino Trona-Athol and Telegraph 10
Victorville-14306 Park Avenue 6
North Coast Humboldt Eureka-Jacobs 5 North Central Coast Santa Cruz Davenport 11*

South Coast Los Angeles Burbank-W Palm Avenue 8* Los Angeles-North Main Street 7 Los Angeles-Westchester Parkway 15* North Long Beach 20 Orange Costa Mesa-Mesa Verde Drive 7
Riverside Riverside-Rubidoux 7 San Bernardino Fontana-Arrow Highway 6

South Central Coast San Luis Obispo Nipomo-Guadalupe Road 35

Santa Barbara El Capitan Beach 4

Exxon Site 10-UCSB West Campus 4

Goleta-Fairview 3* Las Flores Canyon #1 6 Lompoc-HSandP 2 Lompoc-S H Street 4 Vandenberg Air Force Base-STS Power 3

San Diego San Diego Chula Vista 7 Otay Mesa-Paseo International 22* San Diego-1110 Beardsley Street 17

San Francisco Bay Area Alameda Berkeley-6th Street 12*
Oakland-West 13*

Contra Costa Bethel Island Road 8
Concord-2975 Treat Blvd 14
Crockett-Kendall Avenue 25
Martinez-Jones Street 18 Pittsburg-10th Street 20*
Richmond-7th Street 18
San Pablo-Rumrill Blvd 14*
San Francisco San Francisco-Arkansas Street 15*
Santa Clara San Jose-Jackson Street 5*

Solano Benicia-East 2nd Street 26*

Vallejo-304 Tuolumne Street 8 San Joaquin Valley Fresno Fresno-1st Street 9* Salton Sea Imperial Calexico-Ethel Street 10

Sacramento Valley Sacramento North Highlands-Blackfoot Way 4*
Sacramento-Del Paso Manor 4*

1 Data were extracted on 11/23/2010 from AQMIS Merge d. The 2009 SO2 1-hour Federal Design Values were calculated based on the 3- year average of the annual 99th percentile of the 1 -hour daily maximum concentrations (2007, 2008, 200 9). The Federal 1-hour SO2 standard is 75 ppb and was effective August 23, 201 0. All SO2 1-hour Federal Design Values in Califor nia are below the standard of 75 ppb.

* Sites do not meet the EPA's data completeness cr iteria. No monitoring data are available for the f ollowing air basins: Great Basin Valleys, Lake County, Lake Tahoe, Mountain Counties, Northea st Plateau.

### Enclosure 2

California SO 2 

### Attainment Area Boundary Descriptions

1 North Coast Basin

a) All of Del Norte County b) All of Humboldt County c) All of Mendocino County d) All of Trinity County e) That portion of Sonoma County which lies north a nd west of a line described as
follows:

Beginning at the southeasterly corner of the Rancho Estero Americano, being on the boundary line between Marin and Sonoma Counties , California; thence running northerly along the easterly boundary line of said Rancho Estero Americano to the northeasterly corner thereof, bein g an angle corner in the westerly boundary line of Rancho Canada de Jonive; thence running along said boundary of Rancho Canada de Jonive westerly, north erly and easterly to its intersection with the easterly line of Graton Road; thence running along the easterly and southerly line of Graton Road, norther ly and easterly to its intersection with the easterly line of Sullivan Roa d; thence running northerly along said easterly line of Sullivan Road to the so utherly line of Green Valley Road; thence running easterly along the said southe rly line of Green Valley Road and easterly along the southerly line of State High way 116, to the westerly line of Vine Hill Road; thence running along the westerly a nd northerly line of Vine Hill Road, northerly and easterly to its intersection wi th the westerly line of Laguna Road; thence running northerly along the westerly l ine of Laguna Road and the northerly projection thereof to the northerly line of Trenton Road; thence running westerly along the northerly line of said Trenton R oad to the easterly line of Trenton-Healdsburg Road; thence running northerly a long said easterly line of Trenton-Healdsburg Road to the easterly line of Eas tside Road; thence running northerly along said easterly line of Eastside Road to its intersection with the southerly line of Rancho Sotoyome; thence running e asterly along said southerly line of Rancho Sotoyome to its intersection with th e Township line common to Townships 8 and 9 North, M.D.M.; thence running eas terly along said township line to its intersection with the boundary line bet ween Sonoma and Napa Counties, State of California.

### Enclosure 2

California SO 2 

### Attainment Area Boundary Descriptions

2 San Francisco Bay Area Basin

a) That portion of Sonoma County which lies south a nd east of a line described as
follows:

Beginning at the southeasterly corner of the Rancho Estero Americano, being on the boundary line between Marin and Sonoma Counties , California; thence running northerly along the easterly boundary line of said Rancho Estero Americano to the northeasterly corner thereof, bein g an angle corner in the westerly boundary line of Rancho Canada de Jonive; thence running along said boundary of Rancho Canada de Jonive westerly, north erly and easterly to its intersection with the easterly line of Graton Road; thence running along the easterly and southerly line of Graton Road, norther ly and easterly to its intersection with the easterly line of Sullivan Roa d; thence running northerly along said easterly line of Sullivan Road to the so utherly line of Green Valley Road; thence running easterly along the said southe rly line of Green Valley Road and easterly along the southerly line of State High way 116, to the westerly line of Vine Hill Road; thence running along the westerly a nd northerly line of Vine Hill Road, northerly and easterly to its intersection wi th the westerly line of Laguna Road; thence running northerly along the westerly l ine of Laguna Road and the northerly projection thereof to the northerly line of Trenton Road; thence running westerly along the northerly line of said Trenton R oad to the easterly line of Trenton-Healdsburg Road; thence running northerly a long said easterly line of Trenton-Healdsburg Road to the easterly line of Eas tside Road; thence running northerly along said easterly line of Eastside Road to its intersection with the southerly line of Rancho Sotoyome; thence running e asterly along said southerly line of Rancho Sotoyome to its intersection with th e Township line common to Townships 8 and 9 North, M.D.M.; thence running eas terly along said township line to its intersection with the boundary line bet ween Sonoma and Napa Counties, State of California.

b) All of Napa County c) That portion of Solano County which lies south a nd west of a line described as
follows:

Beginning at the intersection of the westerly bound ary of Solano County and the 1/4 section line running east and west through the center of Section 34, T6N, R2W, M.D.B. & M., thence east along said 1/4 sectio n line to the east boundary

### Enclosure 2

California SO 2 

### Attainment Area Boundary Descriptions

3 of Section 36, T6N, R2W, thence south 1/2 mile and east 2.0 miles, more or less, along the west and south boundary of Los Putos Ranc ho to the northwest corner of Section 4, T5N, R1W, thence east along a line co mmon to T5N and T6N to the northeast corner of Section 3, T5N, R1E, thence sou th along section lines to the southeast corner of Section 10, T3N, R1E, thence ea st along section lines to the south 1/4 corner of Section 8, T3N, R2E, thence eas t to the boundary between
Solano and Sacramento Counties.

d) All of Contra Costa County e) All of Alameda County f) All of Santa Clara County g) All of San Mateo County h) All of San Francisco County i) All of Marin County

North Central Coast Basin

a) All of Santa Cruz County b) All of San Benito County c) All of Monterey County

South Central Coast Basin

a) All of San Luis Obispo County b) All of Santa Barbara County c) All of Ventura County

South Coast Air Basin

a) All of Orange County b) That portion of Riverside County which lies west of a line described as follows:

Beginning at the Riverside-San Diego County boundar y and running north along the range line common to R. 4 E and R. 3 E; then ea st along the township line

### Enclosure 2

California SO 2 

### Attainment Area Boundary Descriptions

4 common to T. 8 S and T. 7 S; then north along the r ange line common to R. 5 E and R. 4 E; then west along the township line commo n to T. 6 S and T. 7 S to the southwest corner of Section 34, T. 6 S, R. 4 E; the n north along the west boundaries of Sections 34, 27, 22, 15, 10, 3, T. 6 S, R. 4 E; then west along the township line common to T. 5 S and T. 6 S; then nor th along the range line common to R. 4 E and R. 3 E; then west along the so uth boundaries of Sections 13, 14, 15, 16, 17 and 18, T. 5 S. R. 3 E; then nor th along the range line common
to R. 2 E and R. 3 E to the Riverside-San Bernardin o County line.

c) That portion of San Bernardino County west and s outh of a line described as
follows:

Beginning at the San Bernardino-Riverside County bo undary and running north along the range line common to R. 3 E and R. 2 E; t hen west along the township
line common to T. 3 N and T. 2 N to the San Bernard ino-Los Angeles County boundary.

d) That portion of Los Angeles County which lies so uth and west of a line described
as follows:

Beginning at the Los Angeles-San Bernardino County boundary and running west along the township line common to T.3 N and T. 2 N, San Bernardino Base and Meridian; then north along the range line commo n to R.8 W and R.9 W; then west along the township line common to T.4 N and T. 3 N; then north along the range line common to R.12 W and R.13 W to the south east corner of Section 12, T.5 N, R. 13 W; then west along the south boundarie s of Sections 12, 11, 10, 9, 8, 7, T.5 N, R. 13 W to the boundary of the Angeles National Forest which is collinear with the range line common to R. 13 W and R. 14 W; then north and west along the Angeles National Forest boundary to the point of intersection with the township line common to T.7 N and T. 6 N (point is at the northwest corner of Section 4 in T.6 N, R. 14 W); then west along the t ownship line common to T.7 N and T.6 N; then north along the range line common t o R. 15 W and R. 16 W to the southeast corner of Section 13, T.7 N, R. 16 W; then along the south boundaries of Sections 13, 14, 15, 16, 17, 18, T.7 N, R. 16 W; then north along the range line common to R.16 W and R. 17 W to the north boundary of the Angeles National Forest (collinear with township li ne common to T.8 N and T.7 N); then west and north along the Angeles National Forest boundary to the point of intersection with the south boundary of the Ranc ho La Liebre Land Grant; then

### Enclosure 2

California SO 2 

### Attainment Area Boundary Descriptions

5 west and north along this land grant boundary to th e Los Angeles-Kern County boundary.

Northeast Plateau Basin

a) All of Modoc County b) All of Lassen County c) All of Siskiyou County

Sacramento Valley Basin

a) All of Tehama County b) All of Glenn County c) All of Butte County d) All of Colusa County e) All of Yolo County f) All of Sutter County g) All of Yuba County h) All of Sacramento County i) All of Shasta County. j) That portion of Solano County which lies north a nd east of a line described as
follows:

Beginning at the intersection of the westerly bound ary of Solano County and the 1/4 section line running east and west through the center of Section 34, T6N, R2W, M.D.B. & M., thence east along said 1/4 sectio n line to the east boundary of Section 36, T6N, R2W, thence south 1/2 mile and east 2.0 miles, more or less, along the west and south boundary of Los Putos Ranc ho to the northwest corner of Section 4, T5N, R1W, thence east along a line co mmon to T5N and T6N to the northeast corner of Section 3, T5N, R1E, thence sou th along section lines to the southeast corner of Section 10, T3N, R1E, thence ea st along section lines to the south 1/4 corner of Section 8, T3N, R2E, thence eas t to the boundary between
Solano and Sacramento Counties.

k) That portion of Placer County which lies west of Range 9 east, M.D.B. & M.

### Enclosure 2

California SO 2 

### Attainment Area Boundary Descriptions

6 San Joaquin Valley Basin

a) All of San Joaquin County b) All of Stanislaus County c) All of Merced County d) All of Madera County e) All of Fresno County f) All of Kings County g) All of Tulare County h) That portion of Kern County which lies west and north of a line described as
follows:

Beginning at the Kern-Los Angeles County boundary a nd running north and east along the northwest boundary of the Rancho La Libre Land Grant to the point of intersection with the range line common to R. 16 W. and R. 17 W., San Bernardino Base and Meridian; north along the range line to the point of intersection with the Rancho El Tejon Land Grant bo undary; then southeast, northeast, and northwest along the boundary of the Rancho El Tejon Land Grant to the northwest corner of S. 3, T. 11 N., R. 17 W. ; then west 1.2 miles; then north to the Rancho El Tejon Land Grant boundary; t hen northwest along the Rancho El Tejon line to the southeast corner of S. 34, T. 32 S., R. 30 E., Mount Diablo Base and Meridian; then north to the northwe st corner of S. 35, T. 31 S., R. 30 E.; then northeast along the boundary of the Rancho El Tejon Land Grant to the southwest corner of S. 18, T. 31 S., R. 31 E .; then east to the southeast corner of S. 13, T. 31 S., R. 31 E.; then north alo ng the range line common to R. 31 E. and R. 32 E., Mount Diablo Base and Meridian, to the northwest corner of S. 6, T. 29 S., R. 32 E.; then east to the southwes t corner of S. 31, T. 28 S., R. 32 E.; then north along the range line common to R. 31 E. and R. 32 E. to the northwest corner of S. 6, T. 28 S., R. 32 E., then west to the southeast corner of S. 36, T. 27 S., R. 31 E., then north along the ran ge line common to R. 31 E. and R. 32 E. to the Kern-Tulare County boundary.

Great Basin Valleys Basin

a) All of Alpine County b) All of Mono County c) All of Inyo County

### Enclosure 2

California SO 2 

### Attainment Area Boundary Descriptions

7 Mojave Desert Air Basin

a) That portion of Riverside County which lies east of a line described as follows:

That segment of the southwestern boundary line of H ydrologic Unit Number 18100100 within Riverside County*, further describe d as follows:

Beginning at the Riverside-Imperial County boundary and running north along the range line common to R. 17 E. and R. 16 E., San Ber nardino Base and Meridian; then northwest along the ridge line of the Chuckwal la Mountains, through T. 8 S., R. 16 E. and T. 7 S., R. 16 E., until the Black But te Mountain, elev. 4504 '; then west and northwest along the ridge line to the sout hwest corner of T. 5 S., R. 14 E.; then north along the range line common to R. 14 E. and R. 13 E.; then west and northwest along the ridge line to Monument Moun tain, elev. 4834 '; then southwest and then northwest along the ridge line o f the Little San Bernardino Mountains to Quail Mountain, elev. 5814 '; then nor thwest along the ridge line to the Riverside-San Bernardino County line.

b) That portion of San Bernardino County east and n orth of a line described as
follows:

Beginning at the San Bernardino-Riverside County bo undary and running north along the range line common to R. 3 E and R. 2 E, S an Bernardino Base and Meridian; then west along the township line common to T. 3 N and T. 2 N to the San Bernardino-Los Angeles County boundary.

c) That portion of Los Angeles County which lies no rth and east of a line described
as follows:

Beginning at the Los Angeles-San Bernardino County boundary and running west along the township line common to T. 3 N and T . 2 N, San Bernardino Base and Meridian; then north along the range line commo n to R. 8 W and R. 9 W; then west along the township line common to T. 4 N and T. 3 N; then north along the range line common to R. 12 W and R. 13 W to the southeast corner of Section 12, T. 5 N, R. 13 W; then west along the so uth boundaries of Sections 12, 11, 10, 9, 8, 7, T. 5 N, R. 13 W to the boundar y of the Angeles National Forest which is collinear with the range line commo n to R. 13 W and R. 14 W; then north and west along the Angeles National Fore st boundary to the point of

### Enclosure 2

California SO 2 

### Attainment Area Boundary Descriptions

8 intersection with the township line common to T. 7 N and T. 6 N (point is at the northwest corner of Section 4 in T. 6 N, R. 14 W); then west along the township line common to T. 7 N and T. 6 N; hen north along t he range line common to R.
15 W and R. 16 W to the southeast corner of Section 13, T. 7 N, R. 16 W; then along the south boundaries of Sections 13, 14, 15, 16, 17, 18, T. 7 N, R. 16 W; then north along the range line common to R. 16 W a nd R. 17 W to the north boundary of the Angeles National Forest (collinear with township line common to T. 8 N and T. 7 N) then west and north along the An geles National Forest boundary to the point of intersection with the sout h boundary of the Rancho La Liebre Land Grant; then west and north along this l and grant boundary to the Los Angeles-Kern County boundary. d) That portion of Kern County east and south of a line described as follows:

Beginning at the Kern-Los Angeles County boundary a nd running north and east along the northwest boundary of the Rancho La Libre Land Grant to the point of intersection with the range line common to R. 16 W. and R. 17 W., San Bernardino Base and Meridian; north along the range line to the point of intersection with the Rancho El Tejon Land Grant bo undary; then southeast, northeast, and northwest along the boundary of the Rancho El Tejon Land Grant to the northwest corner of S. 3, T. 11 N., R. 17 W. ; then west 1.2 miles; then north to the Rancho El Tejon Land Grant boundary; t hen northwest along the Rancho El Tejon line to the southeast corner of S. 34, T. 32 S., R. 30 E., Mount Diablo Base and Meridian; then north to the northwe st corner of S. 35, T. 31 S., R. 30 E.; then northeast along the boundary of the Rancho El Tejon Land Grant to the southwest corner of S. 18, T. 31 S., R. 31 E .; then east to the southeast corner of S. 13, T. 31 S., R. 31 E.; then north alo ng the range line common to R. 31 E. and R. 32 E., Mount Diablo Base and Meridian, to the northwest corner of S. 6, T. 29 S., R. 32 E.; then est to the southwest corner of S. 31 T. 28 S., R. 32 E.; then north along the range line common to R. 31 E. and R. 32 E. to the northwest corner of S. 6, T. 28 S., R. 32 E., then west to the southeast corner of S. 36, T. 27 S., R. 31 E., then north along the ran ge line common to R. 31 E. and R. 32 E. to the Kern-Tulare County boundary.

San Diego Air Basin

All of San Diego County.

### Enclosure 2

California SO 2 

### Attainment Area Boundary Descriptions

9 Mountain Counties Air Basin

a) All of Plumas County b) All of Sierra County c) All of Nevada County d) All of Amador County e) All of Calaveras County f) All of Tuolumne County g) All of Mariposa County h) All of El Dorado County except that portion incl uded in the Lake Tahoe Air Basin, as defined in Section 60113(a). i) All of Placer County except that portion include d in the Lake Tahoe Air Basin, as defined in Section 60113(b), and that portion inclu ded in the Sacramento Valley Air Basin, as defined in Section 60106(k).

Lake County Air Basin

All of Lake County.

Lake Tahoe Air Basin

a) That portion of El Dorado County within the drai nage area naturally tributary to Lake Tahoe including said Lake.

b) That portion of Placer County within the drainag e area naturally tributary to Lake Tahoe including said Lake, plus that area in the vi cinity of the head of the Truckee River described as follows: commencing at t he point common to the aforementioned drainage area crestline and the line common to Townships 15 North and 16 North, M.D.B. & M., and following that line in a westerly direction to the northwest corner of Section 3, Township 15 Nort h, Range 16 East, M.D.B. & M., thence south along the west line of Sections 3 and 10, Township 15 North, Range 16 East, M.D.B. & M., to the intersection wit h the said drainage area crestline, thence following the said drainage area boundary in a southeasterly, then northeasterly direction to and along the Lake Tahoe Dam, thence following the said drainage area crestline in a northeasterly , then northwesterly direction to

### Enclosure 2

California SO 2 

### Attainment Area Boundary Descriptions

10 the point of beginning.

Salton Sea Air Basin

a) All of Imperial County b) That portion of Riverside County which lies east of a line described as follows:

Beginning at the Riverside-San Diego County boundar y and running north along the range line common to R. 4 E and R. 3 E; then ea st along the township line common to T. 8 S and T. 7 S; then north along the r ange line common to R. 5 E and R. 4 E; then west along the township line commo n to T. 6 S and T. 7 S to the southwest corner of Section 34, T. 6 S, R. 4 E; the n north along the west boundaries of Sections 34, 27, 22, 15, 10, 3, T. 6 S, R. 4 E; then west along the township line common to T. 5 S and T. 6 S; then nor th along the range line common to R. 4 E and R. 3 E; then west along the so uth boundaries of Sections 13, 14, 15, 16, 17 and 18, T. 5 S. R. 3 E; then nor th along the range line common to R. 2 E and R. 3 E to the Riverside-San Bernardin o County line;

and west of a line described as follows:

That segment of the southwestern boundary line of H ydrologic Unit Number 18100100 within Riverside County*, further describe d as follows:

Beginning at the Riverside-Imperial County boundary and running north along the range line common to R. 17 E. and R. 16 E., San Ber nardino Base and Meridian; then northwest along the ridge line of the Chuckwal la Mountains, through T. 8 S., R. 16 E. and T. 7 S., R. 16 E., until the Black But te Mountain, elev. 4504 '; then west and northwest along the ridge line to the sout hwest corner of T. 5 S., R. 14 E.; then north along the range line common to R. 14 E. and R. 13 E.; then west and northwest along the ridge line to Monument Moun tain, elev. 4834 '; then southwest and then northwest along the ridge line o f the Little San Bernardino Mountains to Quail Mountain, elev. 5814 '; then nor thwest along the ridge line to the Riverside-San Bernardino County line.

*Hydrologic Unit Map, 1978, State of California (So uthern Half), Department of the Interior, Geological Survey, Reston, Virginia (Repr inted 1987), incorporated by reference herein.