FINAL 2007 AQMP 

APPENDIX II 

CURRENT AIR QUALITY 

JUNE 2007
SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT 

GOVERNING BOARD 

Chairman: WILLIAM A. BURKE, Ed.D. 

 Speaker of the Assembly Appointee 

Vice Chairman: S. ROY WILSON, Ed.D. 

 Supervisor, Fourth District 

 Riverside County Representative 

MEMBERS:

MICHAEL D. ANTONOVICH 

Supervisor, Fifth District 

Los Angeles County Representative 

BILL CAMPBELL

Supervisor, Third District 

Orange County Representative 

JANE W. CARNEY 

Senate Rules Committee Appointee 

RONALD O. LOVERIDGE 

Mayor, City of Riverside 

Cities Representative, Riverside County 

GARY OVITT 

Supervisor, Fourth District 

San Bernardino County Representative 

JAN PERRY 

Councilmember, City of Los Angeles 

Cities Representative, Los Angeles County, Western Region 

MIGUEL A. PULIDO 

Mayor, City of Santa Ana 

Cities Representative, Orange County 

TONIA REYES URANGA 

Councilmember, City of Long Beach 

Cities Representative, Los Angeles County, Eastern Region 

VACANT 

Governor’s Appointee 

DENNIS YATES 

Mayor, City of Chino 

Cities Representative, San Bernardino County 

EXECUTIVE OFFICER

BARRY R. WALLERSTEIN, D.Env 

.
CONTRIBUTORS

South Coast Air Quality Management District 

Barry R. Wallerstein, D.Env. 

Executive Officer 

Elaine Chang, DrPH 

Deputy Executive Officer 

Planning, Rule Development, & Area Sources 

Laki Tisopulos, Ph.D., P.E. 

Assistant Deputy Executive Officer 

Planning, Rule Development, & Area Sources 

Jill Whynot 

Planning and Rules Manager 

Planning, Rule Development, & Area Sources 

Authors 

SCAQMD - Planning, Rule Development, & Area Sources 

Tom Chico, Program Supervisor 

Shoreh Cohanim, Air Quality Specilaist

Contributors 

SCAQMD – Science & Technology Advancement U. S. Environmental Protction Agency:

Leonard Edwards, Air Quality Data Translator Coe Owen 

Sandra Hom, Sr. Air Quality Chemist 

Hanna Zhuang, Air Quality Data Translator 

 

Reviewed By

Barbara Baird, J.D. - Principal Deputy District Counsel 

Production

Patti Whiting, Staff Specilaist

Ann Scagliola, Secretary 
 i 

Table of Contents 

SUMMARY 

Summary .................................................................................................................II-S-1 

South Coast Air Basin..................................................................................II-S-1 

Riverside County Salton Sea Air Basin.......................................................II-S-2 

Seasonal, Day-of-Week, and Diurnal Variations ........................................II-S-2 

CHAPTER 1 INTRODUCTION 

Air Quality Overview .............................................................................................II-1-1 

Air Quality Standards and Episode Levels.............................................................II-1-2 

South Coast Air Quality Management District.......................................................II-1-3 

South Coast, Salton Sea, and Mojave Desert Air Basins .......................................II-1-4 

Weather ...................................................................................................................II-1-4 

Emissions. ...............................................................................................................II-1-5

Air Quality Trends ..................................................................................................II-1-6 

Air Quality in the District Compared to Other Areas of the U.S. ..........................II-1-7 

CHAPTER 2 AIR QUALITY IN THE SOUTH COAST AIR BASIN 

Air Quality in the South Coast Air Basin ...............................................................II-2-1 

Ozone (O3) ..............................................................................................................II-2-1 

Suspended Particulate Matter .................................................................................II-2-9 

Particulate Matter (PM10)........................................................................................II-2-9 

Fine Particulate Matter (PM2.5).............................................................................II-2-14 

Carbon Monoxide (CO) ........................................................................................II-2-17 

Nitrogen Dioxide (NO2)........................................................................................II-2-19 

Sulfur Dioxide (SO2).............................................................................................II-2-20 

Sulfate (SO4

=

)........................................................................................................II-2-22 

Lead (Pb)...............................................................................................................II-2-23

CHAPTER 3 AIR QUALITY IN THE RIVERSIDE COUNTY SSAB 

Air Quality in the Riverside County SSAB............................................................II-3-1 

Ozone (O3) ..............................................................................................................II-3-2 

Particulate Matter (PM10)........................................................................................II-3-3 

Fine Particulate Matter (PM2.5)...............................................................................II-3-4 

Carbon Monoxide (CO) ..........................................................................................II-3-4 

Nitrogen Dioxide (NO2)..........................................................................................II-3-4 

Sulfur Dioxide (SO2)...............................................................................................II-3-5 
Final 2007 AQMP Appendix II: Current Air Quality 

ii

Sulfate (SO4

=

)..........................................................................................................II-3-5 

Lead (Pb).................................................................................................................II-3-5 

LIST OF FIGURES: 

Figure 1-1: 2005 Maximum Pollutant Concentrations As 

Percent of Standards ....................................................................................II-1-1 

Figure 1-2: South Coast Air Quality Management District...................................II-1-3 

Figure 1-3: 2002 Average Daily Emissions in the Basin ......................................II-1-5 

Figure 1-4: Percent Basin-Days Exceeding the Federal Satandard, 

1990-2005 ....................................................................................................II-1-6 

Figure 2-1: Number of Days per Month Exceeding State or 

Federal Standards in 2005............................................................................II-2-2 

Figure 2-2: Ozone - 2005, Number of Days Exceeding 1-Hour 

Federal Standard ..........................................................................................II-2-5 

Figure 2-3: Ozone - 2005, Number of Days Exceeding 8-Hour 

Federal Standard ..........................................................................................II-2-5 

Figure 2-4: Number of Days Per Month Exceeding 

Federal Ozone Standard in the Basin...........................................................II-2-6 

Figure 2-5: Ozone, Diurnal Variation, 2005, Maximum 8-Hour Average 

Concentration for Each Hour in the Basin...................................................II-2-7 

Figure 2-6: Ozone, Day-of-Week Variation, 2005, Exceedances 

of the Federal Standard by Day of Week.....................................................II-2-8 

Figure 2-7: Particulate Matter (PM10) - 2005, Annual 

Arithmetic Mean, μg/m3............................................................................II-2-10

Figure 2-8: Basin-Days Exceeding State PM10 Standard by 

Month, 2003-2005 .....................................................................................II-2-12 

Figure 2-9: Monthly Average PM10 Concentration, 2003-2005 ........................II-2-12 

Figure 2-10: Day-of-Week Variation, 2003-2005, Average PM10 

Concentration by Day of Week .................................................................II-2-13 
 iii 

Figure 2-11: Diurnal Variation, 2005, Average PM10 Concentration 

for Each Hour of the Day...........................................................................II-2-13 

Figure 2-12: Fine Particulate Matter (PM2.5) - 2005, Annual 

Arithmetic Mean, μg/m3............................................................................II-2-15

Figure 2-13: PM2.5 Seasonal Variation, 2005, Monthly Average 

Concentration in the Basin, μg/m3 ............................................................II-2-16 

Figure 2-14: PM2.5 Day-of-Week Variation, 2003-2005, Basin-Days 

Exceeding the Federal Standard by Day of Week.....................................II-2-16 

Figure 2-15: Diurnal Variation, 2003-2005, Average PM2.5 Concentration 

for Each Hour of the Day...........................................................................II-2-17 

Figure 3-1: 2005 Maximum Pollutant Concentrations as Percent of 

Standards, Riverside County SSAB ............................................................II-3-1 

Figure 3-2: Ozone, 1990-2005, Number of Days Exceeding Federal 

Standards in Riverside County SSAB .........................................................II-3-3 

LIST OF TABLES: 

Table 1: 2005 Maximum 8-Hour Average Carbon Monoxide 

Concentrations ...........................................................................................II-2-19 

Table 2: 2005 Maximum Annual Average Nitrogen Dioxide 

Concentrations ...........................................................................................II-2-20 

Table 3: 2005 Maximum 24-Hour Average Sulfur Dioxide 

Concentrations ...........................................................................................II-2-21 

Table 4: 2005 Maximum 24-Hour Average Sulfate Concentrations...................II-2-22 

Table 5: 2005 Maximum Quarterly Average Lead Concentrations ....................II-2-23 
Final 2007 AQMP Appendix II: Current Air Quality 

iv

ATTACHMENT LIST: 

Table A-1: Ambient Air Quality Standards 

Table A-2: Episode Criteria 

Table A-3: Air Monitoring Stations and Source/Receptor Areas 

Figure A-1: South Coast Air Basin and Adjoining Areas of Salton Sea Air Basin 

Table A-4: Ozone - Number of Days Exceeding the Federal Standard (0.08 ppm, 

8-Hour Average) 

Table A-5: Ozone - Number of Days Exceeding the Federal Standard (0.12 ppm, 

1-Hour Average) 

Table A-6: Ozone - Number of Days of First/Second Stage Episodes, 1990-2005 

Table A-7: Ozone - Annual Maximum 1-Hour, ppm, 1976-2005 

Table A-8: Particulate Matter (PM10), Annual Arithmetic Mean, 

μg/m

3

, 1990-2005 

Table A-9: Particulate Matter (PM10) - Percent of Sampling Days 

Exceeding State Standard and Federal Standards, 1990-2005 

Table A-10: Particulate Matter (PM10), Annual Maximum 24-Hour 

Average, μg/ m

3

, 1990-2005 

Table A-11-: Fine Particle Matter (PM2.5), Annual Arithmetic Mean, μg/m

3

, 

1999-2005 

Table A-12: Fine Particulate Matter (PM2.5) - Percent of Sampling Days 

Exceeding Federal Standard (65 μg/m

3

), 1999-2000 

Table A-13: Fine Particulate Matter (PM2.5) - Percent of Sampling Days 

Exceeding the New Federal Standard (35 μg/m

3

), 1999-2000 

Table A-14: Particulate Matter (PM2.5), Annual Maximum 24-Hour 

Average, μg/m

3

, 1999-2005 

Table A-15: Particulate Matter (PM2.5) - 24-Hour Average 98th Percentile 

Concentration, μg/ m3

, 1999-2005 

Table A-16: Carbon Monoxide - Number of Days Maximum 8-Hour Average 

Exceeded the Federal Standard, 1990-2005 
 v 

Table A-17: Carbon Monoxide - Number of Days Maximum 8-Hour Average 

Exceeded the Federal Alert Level, 1990-2005 

Table A-18: Carbon Monoxide, Annual Maximum 8-Hour Average, ppm, 

1990-2005 

Table A-19: Nitrogen Dioxide - Annual Average of All Hours, pphm, 1990-2005 

Table A-20: Nitrogen Dioxide - Number of Days 1-Hour Average Exceeded 

the State Standard, 1990-2005 

Table A-21: Nitrogen Dioxide, Annual Maximum 1-Hour, ppm, 1990-2005 

Table A-22: Sulfur Dioxide - Annual Average, pphm, 1990-2005 

Table A-23: Sulfur Dioxide, Annual Maximum 1-Hour Average, ppm, 1990-2005 

Table A-24: Sulfate - Percent of Sampling Days Exceeding the State Standard, 

1990-2005 

Table A-25: Sulfate - Maximum 24-Hour Averages, 1990-2005 

Table A-26: Lead - Highest Calendar Quarter Mean, μg/m

3

, 1990-2005 

Table A-27: Lead - Highest Monthly Averages, μg/m

3

, 1990-2005 
SUMMARY 

South Coast Air Basin 

Riverside County Salton Sea Air Basin 

Seasonal, Day-of-Week, and Diurnal Variations 
Summary 

 II-S-1 

SUMMARY 

This appendix contains a summary of the year 2005 air quality in the South Coast Air 

Basin (Basin) and the portion of Salton Sea Air Basin (SSAB) monitored by the AQMD. 

The Basin includes Orange county and the non-desert portions of Los Angeles, 

Riverside and San Bernardino counties. For those pollutants for which the Basin is in 

nonattainment of the federal standards (O3; PM10; and PM2.5), air quality trends 

through the year 2005 are presented. Chapter 1 of this appendix presents brief 

descriptions of the pollutant emissions in the Basin, ambient air quality standards, and 

criteria air pollutant concentrations and trends in the region. Chapters 2 and 3 present a 

description of each of the criteria pollutant’s properties, current concentration compared 

to the state and federal standards, and spatial, seasonal, and diurnal variations in the 

Basin and SSAB. 

In 2005, the AQMD monitored concentrations of air pollutants at 34 locations in 

southern California’s Los Angeles, Orange, Riverside and San Bernardino counties. 

Pollutant concentrations exceeded the federal and state standards for ozone and 

particulate matter (PM10, PM2.5). Standards for carbon monoxide, nitrogen dioxide, 

sulfur dioxide, sulfate, and lead were not exceeded. In the year 2005, the U.S. location 

with the highest number of days exceeding the federal ozone standard was located in the 

Basin. 

South Coast Air Basin 

In 2005, there were a total of 89 days on which the federal standards for 8-hour ozone or 

24-hour PM2.5 were exceeded at one or more Basin locations. (The other criteria 

pollutants did not exceed the daily federal standards.) 

The number of days exceeding the federal ozone standard varied widely by area, from 

zero to 69 days, depending on location. Exceedances were fewest at the coast, 

increasing to a maximum in the Basin's Central San Bernardino Mountains and inland 

valleys. The Central San Bernardino Mountains area exceeded the federal 8-hour 

average ozone standard most frequently (69 days). The previous federal 1-hour ozone 

standard was exceeded on 18 days. The more stringent 1-hour and 8-hour average state 

standards were exceeded on 80 and 102 days, respectively, in the same area. The 

highest 1-hour average and 8-hour average ozone concentration recorded in 2005 (0.182 

ppm and 0.145 ppm) were 146 percent and 171 percent of the federal 1-hour and 8-hour 

standards, respectively. 

Exceedances of the federal annual PM10 standard were confined to Riverside county, 

primarily in and around the Metropolitan Riverside County area. The more stringent 

state annual PM10 standard was exceeded in a much larger area, covering most of the 
Final 2007 AQMP Appendix II: Current Air Quality 

II-S-2

Basin. The federal 24-hour PM10 standard was not exceeded at any of the areas 

monitored in the District in 2005. The state 24-hour standard, however, was exceeded at 

most of the locations monitored, with the Metropolitan Riverside county area exceeding 

most frequently (56 percent of sampling days). The maximum 24-hour average and 

annual PM10 concentrations (131.0 μg/m3 and 52.0 μg/m3

) were 87 percent and 103 

percent of the federal 24-hour and annual standards, respectively. 

Maximum 24-hour average and annual average PM2.5 concentrations (132.7 μg/m3

recorded in the East San Gabriel Valley area and 21.0 μg/m3

 recorded in the 

Metropolitan Riverside County area) were 203 percent and 139 percent of the federal 

24-hour and annual standards, respectively. 

In 2005, carbon monoxide concentrations did not exceed the standards anywhere in the 

Basin for the third consecutive year. The maximum 8-hour average concentration of 5.9 

ppm, recorded in South Central Los Angeles County, was 62 percent of the federal 

standard. 

Riverside County Salton Sea Air Basin 

Pollutant concentrations in the Riverside county portion of the SSAB were monitored at 

two locations in the Coachella Valley in 2005, and exceeded the federal and state 

standards for ozone and the state PM10 standards. No other standards were exceeded. 

The highest 1-hour and 8-hour ozone concentrations recorded in the Coachella Valley in 

2005 (0.139 ppm and 0.116 ppm) were 111 percent and 136 percent of the federal 1-

hour and 8-hour standards, respectively. The federal 8-hour ozone standard was 

exceeded on 39 days in the SSAB in 2005. 

The federal 24-hour and annual PM10 standards were not exceeded at either of the two 

locations monitored in SSAB in 2005. The more stringent state standards, however, 

were exceeded at both locations. PM2.5 concentrations were below the federal 24-hour 

and annual PM2.5 standards. 

Seasonal, Day-of-Week, and Diurnal Variations 

Concentrations of pollutants have been found to vary by season, day of week, and time 

of day, and these variations were examined for 2003-2005 for ozone, PM2.5 and PM10. 

Ozone concentrations generally peak in summer. Maximum 24-hour PM10 and PM2.5 

concentrations peak in fall and winter months; however, seasonal variations for 

particulates are not as distinct as ozone concentration variations. Ozone concentrations 

tend to be higher on weekends than on weekdays and the time of day with highest 

average ozone concentrations is early afternoon in the peak ozone area. PM10 and 
Summary 

 II-S-3 

PM2.5 concentrations vary slightly on each day of the week and day-of-week variations 

depend on the location. Basinwide particulate matter variations show slightly higher 

overall PM2.5 concentrations on Saturday. 
CHAPTER 1 

INTRODUCTION 

Air Quality Overview 

Air Quality Standards and Episode Levels 

South Coast Air Quality Management District 

South Coast, Salton Sea, and Mojave Desert Air Basins 

Weather 

Emissions 

Air Quality Trends 

Air Quality in the District Compared to Other Areas of the U.S. 
Chapter 1: Introduction

II-1-1 

AIR QUALITY OVERVIEW 

In 2005, the AQMD monitored ambient air quality for criteria pollutants (ozone, 

carbon monoxide, nitrogen dioxide, sulfur dioxide, PM10, PM2.5, lead, and sulfate) 

at 34 locations in Southern California’s South Coast Air Basin (Basin) and in the 

neighboring Riverside county portion of the Salton Sea Air Basin (SSAB) that are 

within the District's jurisdiction. Pollutant concentrations exceeded federal and state 

standards for ozone and particulate matter (PM10 and PM2.5), while other pollutants 

were below the standards. Figure 1-1 shows the maximum pollutant concentrations 

for 2005 as a percentage of the federal and state standards. 

** Higher lead concentrations were recorded at special monitoring sites immediately adjacent to sources known 

to emit lead. 

FIGURE 1-1 

2005 Maximum Pollutant Concentrations as Percent of Standards 

Maximum 1-hour average and 8-hour average ozone concentrations in 2005 (0.182 

ppm and 0.145 ppm) were 146 percent and 171 percent of the federal 1-hour and 8-

hour standards, respectively. Maximum 24-hour average and annual average PM10 

concentrations (131 μg/m3

 and 52.0 μg/m3) were 87 percent and 103 percent of the 

federal 24-hour and annual standards, respectively. Maximum 24-hour average and 

annual average PM2.5 concentrations (132.7 μg/m3

 and 21.0 μg/m3) were, 

Percent of Standards

0

50

100

150

200

250

300

Ozone

(1-Hour)

Ozone

(8-Hour)

Carbon

Monoxide

(8-Hour)

Nitrogen

Dioxide

(Annual)

Sulfur

Dioxide

(Annual)

PM2.5

(Annual)

PM10

(Annual)

Sulfate

(24-Hour)

Lead**

(Quarter)

State Standard

Federal Standard
Final 2007 AQMP Appendix II: Current Air Quality 

II-1-2

respectively, 203 percent and 139 percent of the federal 24-hour and annual 

standards. 

The highest 8-hour average carbon monoxide concentration of the year (5.9 ppm) 

was 62 percent of the federal standard. The maximum annual average nitrogen 

dioxide concentration (0.0313 ppm) was 59 percent of the federal standard; the 

maximum 1-hour average nitrogen dioxide concentration (0.14 ppm) was 54 percent 

of the state standard. The maximum 24-hour sulfate concentration (17.3 μg/m3

) was 

69 percent of the state standard (there is no federal sulfate standard). Sulfur dioxide 

and lead concentrations continued to remain well below the federal and state 

standards in 2005. 

AIR QUALITY STANDARDS AND EPISODE LEVELS 

Both the federal and state governments have adopted ambient air quality standards, 

which define the concentration below which long-term exposure to a pollutant is not 

expected to cause adverse effects to public health and welfare. Episode levels have 

also been established, below which short-term exposures are not expected to be 

injurious to health. The standards and episode levels are summarized in Tables A-1 

and A-2 in the Attachment. 

Both standards and episode levels are periodically reviewed to incorporate the 

findings from the most current research available on the effects of pollutants. In 

1997, the U.S. EPA adopted new federal air quality standards for particulate matter 

and ozone. The 8-hour average ozone standard (0.08 ppm) was developed to protect 

the public health against the effects of prolonged exposure and represented a 

tightening of the previous 1-hour ozone standard. The 1-hour average federal ozone 

standard was revoked by the U.S. EPA and replaced by the 8-hour average ozone 

standard. CARB has also established a new 8-hour average state standard (0.07 

ppm) effective May 17, 2006. 

For particulate matter, federal annual and 24-hour standards and a state annual 

standard for the finest fraction of particulate, PM2.5 (particles less than 2.5 

micrometers), were established in 1997 to complement the PM10 federal and state 

standards that cover a full range of inhalable particulate matter. PM2.5 is believed 

to be the portion of particulate most injurious to health, and causes the greatest 

visibility reduction. Over the years, the forms of the federal 24-hour PM10 standard 

and state annual PM10 standard were also revised. In a recent action by U.S. EPA 

on September 21, 2006, the federal 24-hour average PM2.5 standard was revised, 

significantly strengthening the daily standard for fine particles (from 65 μg/m3

 to 35 

μg/m3

). The federal annual average PM10 standard was revoked, with U.S. EPA 

finding no evidence of adverse health effects due to long-term exposure to coarse 
Chapter 1: Introduction

II-1-3 

particles at the current standard level. The federal 24-hour PM10 standard and state 

24-hour and annual standards were retained. 

SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT 

California’s first local air pollution control agency, the Los Angeles County Air 

Pollution Control District (LAAPCD), was formed in 1947, and APCDs were 

formed in Orange, Riverside, and San Bernardino counties not long afterward. 

These four agencies combined in 1976 to form the Southern California APCD, 

which was later replaced by the South Coast Air Quality Management District and 

the Mojave Desert AQMD. 

The South Coast Air Quality Management District (AQMD or District) was 

established by state legislation effective February 1, 1977, and was assigned 

jurisdiction over air quality in the South Coast Air Basin. The District is also 

responsible for air quality in the Riverside county area of the Salton Sea Air Basin 

(SSAB), by contract with the county. The region encompassed by the District is 

shown in Figure 1-2. In 2005, the District maintained a network of 32 air 

monitoring stations in the Basin and an additional two in the District portions of 

SSAB (shown in Figure A-1 and Table A-3 in the Attachment). 

FIGURE 1-2 

South Coast Air Quality Management District 

COUNTY

MDAB

South Coast

Air Quality Management District

0 50

SOUTH C OAST

AIR B ASIN (SOCA B)

MOJAV E DE SE RT AIR

BASIN (MDAB)

SCA QMD J URISDIC TION

J UN E 1996 R EVISION

MILES

LOS ANGELES COUNTY

RI VER SIDE C OUNT Y

KE RN C OUNTY

IMPERIAL COUNT Y

SAN DIEGO C OUNTY BOUNDAR IES COUN TY

Antel ope Valley

SCAQM D AIR

MONITOR ING STATION

SOCAB SAN BERNARDINO COU NTY

ORANGE

COUNTY

Coachella

Valley

SSAB

SA LTON SEA

AIR B ASIN (SSAB)
Final 2007 AQMP Appendix II: Current Air Quality 

II-1-4

SOUTH COAST, SALTON SEA, AND MOJAVE DESERT AIR BASINS 

The South Coast Air Basin (Basin) has an area of 6,800 square miles and a 

population of 16 million in 2005. It includes all of Orange county and the nondesert areas of Los Angeles, Riverside, and San Bernardino counties. The Los 

Angeles urban area (the nation’s second largest) and the Anaheim-Fullerton and 

Riverside-San Bernardino urban areas lie within the Basin’s boundaries. About twothirds of the Basin’s population lives within Los Angeles county. 

The Salton Sea Air Basin and the Mojave Desert Air Basin (MDAB) have a 

combined area of approximately 32,200 square miles. The two Basins include the 

desert portions of Los Angeles, Riverside, and San Bernardino counties, as well as 

Imperial county and part of Kern county. 

The AQMD has jurisdiction over the Coachella Valley portion of Riverside county 

in the SSAB. The population in the SSAB portion under the jurisdiction of the 

District is about 380,000. The District also has the jurisdiction over a small portion 

of the MDAB in eastern Riverside county. The area is sparcely populated desert. 

WEATHER 

The South Coast Air Basin is arid, with virtually no rainfall and abundant sunshine 

during the summer months. It has light winds and poor vertical mixing compared to 

the other large urban areas in the U.S. The combination of poor dispersion and 

abundant sunshine provide conditions especially favorable to the formation of 

photochemical smog. The Basin is bounded to the north and east by mountains with 

maximum elevations exceeding 10,000 feet. The unfavorable combination of 

meteorology, topography, and emissions from the nation’s second largest urban area 

result in the Basin having the worst air quality in the U.S. 
Chapter 1: Introduction

II-1-5 

EMISSIONS 

The amount of each of the major pollutants emitted into the atmosphere of the Basin 

in 2002 is shown in Figure 1-3. Year 2002 emissions are the baseline used for the 

2007 AQMP. In 2002, annual average daily emissions were approximately 4,800 

tons of carbon monoxide (CO), 800 tons of volatile organic compounds (VOC), 

1,100 tons of oxides of nitrogen (NOx), 50 tons of oxides of sulfur (SOx), 500 tons 

of total suspended particulate (TSP), 300 tons of directly emitted particulate (PM10), 

and 100 tons of fine particulate (PM2.5). (Additional PM10 forms through chemical 

reaction of the gaseous pollutants.) Emissions vary relatively little by season, but 

there are large seasonal differences in the atmospheric concentrations of pollutants 

due to seasonal variations in the weather. (Details of the 2002 emissions inventory 

are contained in Appendix III.) 

VOCs and NOx are precursors of ozone. NOx and VOC also react to form nitrates 

and solid organic compounds, which are a significant fraction of PM10. SO2 reacts 

to form sulfates which are also significant contributors to the Basin’s PM10 and 

PM2.5 levels. In addition to the PM10 formed by the reaction of gaseous 

precursors, there is directly emitted PM10, most of which is attributed to fugitive 

dust sources such as re-entrained road dust, construction activities, farming 

operations and wind-blown dust. 

FIGURE 1-3 

2002 Average Daily Emissions in the Basin 

012345

PM2.5

PM10

TSP

SOx

NOx

VOC

CO

Thousand Tons/Day
Final 2007 AQMP Appendix II: Current Air Quality 

II-1-6

AIR QUALITY TRENDS 

In 2005, Basin locations exceeded one or more of the federal standards on 89 days 

(based on the current 8-hour ozone and 24-hour PM2.5 standards). Figure 1-4 

shows the long-term annual trend of percent "basin-days" exceedances of the federal 

standards for ozone and particulates. (A "basin-day" is recorded if any location in 

the Basin exceeds the standard. Multiple locations exceeding on the same day count 

as a single basin-day.) 

Percent Basin-Days

0%

25%

50%

75%

100%

90 92 94 96 98 00 02 04

O3 (8-Hour) O3 (1-Hour)

PM2.5 (24-Hour) PM10 (24-Hour)

FIGURE 1-4 

Percent Basin-Days Exceeding Federal Standards, 1990-2005 
Chapter 1: Introduction

II-1-7 

AIR QUALITY IN THE DISTRICT COMPARED TO OTHER AREAS OF 

THE U.S. 

Despite the significant downtrend, the Basin still has some of the worst air quality in 

the nation in terms of the number of days per year exceeding the federal standards. 

In 2005, the U.S. location in terms of highest number of days over the federal 8-hour 

average ozone standard was located in the Basin (Central San Bernardino 

Mountains, 69 days). Other area with the greatest number of exceedances outside 

California was located in the Dallas Metropolitan Area in Texas (18 days). 

The Basin did not exceed the federal 24-hour average PM10 standard in 2005 and 

the annual PM10 standard was exceeded at one location only. The Basin exceeded 

the 24-hour average PM2.5 standard by the widest margin nationwide in 2005, but 

the 98th percentile PM2.5 concentration (which is used to compare with the federal 

PM2.5 standard) was below the standard at all locations monitored in the Basin. 

Over the past decade, reductions in vehicular emissions have reduced carbon 

monoxide levels throughout the U.S.. The Basin was the last area to cease violating 

the standard. The AQMD has petitioned for redesignation to attainment, since 

monitoring for the last several years has not shown any violations. In 2005, the 

Basin did not exceed the carbon monoxide standard for the third consecutive year. 

More detailed information on air quality in the U.S. is available in U.S. EPA's 

annual National Air Quality and Emissions Trend Report (see 

www.epa.gov/airtrends/). 

The following two chapters of this report summarize current air quality in the 

District. Analyses are presented for: 

• Ozone (O3) 

• Carbon monoxide (CO) 

• Nitrogen dioxide (NO2) 

• Sulfur dioxide (SO2) 

• Particulate matter (PM10) 

• Particulate matter (PM2.5) 

• Lead (Pb); and 

• Sulfate (SO4

=

). 

Chapters 2 and 3 contain summaries of air quality in the South Coast Air Basin, and 

the Riverside county portion of the Salton Sea Air Basin, respectively; Salton Sea 

Air Basin includes Coachella Valley. For ozone, PM10, and PM2.5 the pollutants 
Final 2007 AQMP Appendix II: Current Air Quality 

II-1-8

for which the Basin is still designated as nonattainment, maps are presented which 

show how air quality varies in different areas in the Basin. Detailed air quality 

statistics for each of the District’s monitoring locations in the Basin and SSAB are 

contained in the Attachment to this report. 
CHAPTER 2 

AIR QUALITY IN THE SOUTH COAST AIR BASIN 

Air Quality in the South Coast Air Basin 

Ozone (O3) 

Suspended Particulate Matter 

Particulate Matter (PM10) 

Fine Particulate Matter (PM2.5) 

Carbon Monoxide (CO) 

Nitrogen Dioxide (NO2) 

Sulfur Dioxide (SO2) 

Sulfate (SO4

=

) 

Lead (Pb)

Chapter2 : Air Quality in the South Coast Air Basin 

II-2-1 

AIR QUALITY IN THE SOUTH COAST AIR BASIN 

The maximum pollutant concentrations recorded at District monitoring stations in 2005 

(see Figure 1-1 in the previous chapter) were all recorded in the densely populated South 

Coast Air Basin. However, air quality in the Basin varies widely by season and by area. 

The prevailing daytime sea breeze tends to transport pollutants from coastal areas into 

the Basin’s inland valleys, and from there, still further inland into neighboring areas of 

the SSAB, as well as the MDAB. Concentrations of primary pollutants (those emitted 

directly into the air) are typically highest close to the sources which emit them. 

However, secondary pollutants (those formed in the air by chemical reaction of 

precursors) reach maximum concentrations some distance downwind of the sources that 

emit the precursors, due to the fact that the polluted air mass is moved inland many miles 

by the prevailing winds before maximum concentrations are reached. 

In 2005, the federal standards were exceeded on a total of 89 days in the Basin. The 

more stringent state standards were exceeded on 168 days. The Basin’s air quality and 

occurance of exceedances vary with season due to seasonal differences in the weather. 

High ozone concentrations are generally recorded mainly during the May to October 

“smog season” and most frequent number of exceedances are normally recorded in July 

and August. Particulate matter (PM10 and PM2.5) levels do not have a clear pattern like 

ozone, and high concentrations may be recorded throughout the year. However, 

typically, high PM10 concentrations are recorded in summer and fall in inland valley 

areas while coastal areas show high concentrations mostly during late fall and winter 

months. PM2.5 concentrations tend to be higher in fall. Figure 2-1 shows the number of 

days per month when state or federal standards were exceeded in the Basin in 2005. 

OZONE (O3) 

Properties

The Basin's unique air pollution problem was first recognized in the 1940's. Unlike the 

smog in many other urban areas, Los Angeles smog was worse in summer. Early 

research showed that ozone was being formed in the Basin's atmosphere from VOCs and 

NOx being emitted into the air in the presence of steady sunshine. Regular monitoring 

of total oxidants was begun by the Los Angeles Air Pollution Control District 

(LAAPCD) in the 1950’s, and annual maximum 1-hour ozone concentrations in excess 

of 0.6 ppm were recorded at that time. 
Final 2007 AQMP Appendix II: Current Air Quality 

II-2-2 

*The term Basin-days represents the number of days a standard was exceeded by at least one 

monitoring station in the Basin. 

FIGURE 2-1 

Number of Days per Month Exceeding State or Federal Standards in 2005 

Ozone (O3), a colorless gas with a sharp odor, is a highly reactive form of oxygen. High 

ozone concentrations exist naturally in the stratosphere. Some mixing of stratospheric 

ozone downward through the troposphere to the earth's surface does occur; however, the 

extent of ozone transport is limited. At the earth's surface in sites remote from urban 

areas, ozone concentrations are normally very low (0.03-0.05 ppm). 

In urban areas, ozone is formed by a complicated series of chemical and photochemical 

reactions between VOCs, NOx, and the oxygen in the air. A decrease in ozone 

precursors may or may not give a decrease in ozone. Ozone concentrations are 

dependent not only on overall precursor emissions, but on the ratio of VOCs to NOx 

concentration, the reactivity of the specific VOCs present, the spatial and temporal 

distribution of emissions, and weather. 

While ozone is beneficial in the stratosphere because it filters out skin-cancer-causing 

ultraviolet radiation, it is a highly reactive oxidant. It is this reactivity which accounts 

for its damaging effects on materials, plants, and human health at the earth's surface. 

The propensity of ozone to react with organic materials causes it to be damaging to 

living cells, and ambient ozone concentrations in the Basin are frequently sufficient to 

cause health effects. Ozone enters the human body primarily through the respiratory 

tract and causes respiratory irritation and discomfort, makes breathing more difficult 

during exercise, and reduces the respiratory system's ability to remove inhaled particles 

and fight infection. People with respiratory diseases, children, the elderly, and people 

who exercise heavily are more susceptible to the effects of ozone. 

Basin-Days Exceeding*

0

10

20

30

40

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Ozone

PM10

PM2.5

2 or More Standards
Chapter2 : Air Quality in the South Coast Air Basin 

II-2-3 

Plants are sensitive to ozone at concentrations well below the health-based standards and 

ozone is responsible for significant crop damage. Ozone is also responsible for damage 

to forests and other ecosystems. 

8-Hour Ozone Standard

The federal 1-hour ozone standard was revoked by the U.S. EPA and replaced by the 8-

hour average ozone standard. Studies have shown that even relatively low 

concentrations of ozone, if lasting for several hours, can significantly reduce lung 

function in normal healthy people. In July 1997, the U.S. Environmental Protection 

Agency (U.S. EPA) adopted an 8-hour average federal ozone standard with a level of 

0.08 ppm. The 8-hour ozone standard is more stringent than the 1-hour standard and 

provides greater protection to public health than the 1-hour standard. It is intended to 

help protect people who spend a significant amount of time working or playing outdoors 

-- a group that is particularly vulnerable to the effects of ozone. CARB also established 

a new 8-hour average state ozone standard of 0.07 ppm effective May 2006. The state 1-

hour ozone standard continues to remain in effect. 

The effect of the adopted 8-hour ozone standard on this region's attainment of federal 

ozone standards has been evaluated by comparing the number of exceedances of the 

previous 1-hour standard (0.12 ppm 1-hour average) with the number of exceedances of 

8-hour average concentrations of 0.08 ppm. The number of exceedances in different 

areas in the Basin and SSAB vary; however, the federal 8-hour ozone standard level is 

exceeded more frequently in the inland valleys and adjacent mountains where high 

ozone concentrations normally occur. 

Current Ozone Air Quality

In 2005, the District measured ozone concentrations at 29 regular ambient monitoring 

locations. The maximum 1-hour average and 8-hour ozone concentrations in the Basin 

in 2005 (0.182 ppm and 0.145) were 146 percent and 171 percent of the federal 1-hour 

and 8-hour standards, and 192 percent and 193 percent of the state standards, 

respectively. The federal 1-hour ozone standard was exceeded at one or more Basin 

locations on a total of 30 days, the 8-hour standard was exceeded on 84 days. The 

California state 1-hour and 8-hour standards were exceeded on 102 days and 120 days, 

respectively. The stage 1 episode level (1-hour average ≥ 0.20 ppm) was not exceeded 

anywhere in the Basin for the second consecutive year, but the health advisory level 

(0.15 ppm) was exceeded on 11 days. 

Figure 2-2 shows the contour diagrams of the number of days exceeding the federal 

1-hour ozone standard in different areas of the Basin in 2005. The 1-hour ozone 

standard was exceeded most frequently in the Basin's Central San Bernardino Mountains 

and adjacent valleys and in the Santa Clarita Valley area of Los Angeles county. The 

coastal areas of Los Angeles and Orange counties, the metropolitan areas of Los Angeles 

county and the farthest eastern portion of Coachella Valley (extending to the areas near 
Final 2007 AQMP Appendix II: Current Air Quality 

II-2-4 

the boundary between the Basin and San Diego county) did not exceed the 1-hour 

federal ozone standard. 

Figure 2-3 shows the number of days exceeding the 8-hour federal standard in the Basin 

in 2005. The federal 8-hour average standard was also exceeded most frequently in the 

Basin’s Central San Bernardino Mountains and adjacent areas and in the Santa Clarita 

Valley area. The coastal areas did not exceed the federal 8-hour standard. 

The more stringent state standards were exceeded almost everywhere in the Basin with 

the greatest number of exceedances occurring in the Central San Bernardino Mountains 

and adjacent valleys (not shown). 

As monitored, in 2005, stage 1 episodes were not recorded anywhere in the Basin. 

Except for one day in 2003, the stage 1 episode level has not been exceeded in the Basin 

since 1998. There have been no exceedances of the stage 2 episode level (1-hour 

average O3 greater than or equal to 0.35 ppm) since 1988 and the stage 3 episode level 

(1-hour average O3 greater than or equal to 0.50 ppm) has not been exceeded since 1974. 

Tables A-4 and A-5 in the Attachment show the number of exceedances of the federal 

1-hour and 8-hour ozone standard at all District air monitoring sites, for all years for 

which data was available during the period 1990-2005. Tables A-6 and A-7 show the 

number of days exceeding stage 1 and stage 2 episode levels and the maximum 1-hour 

ozone concentrations over the time period 1990 to 2005. Please refer to Appendix II of 

the 2003 AQMP for prior-year statistics (1976-1989). 
Chapter2 : Air Quality in the South Coast Air Basin 

II-2-5 

FIGURE 2-2 

Ozone - 2005 

Number of Days Exceeding 1-Hour Federal Standard 

(1-hour average ozone > 0.12 ppm) 

FIGURE 2-3 

Ozone - 2005 

Number of Days Exceeding 8-Hour Federal Standard 

(8-hour average ozone > 0.08 ppm) 
Final 2007 AQMP Appendix II: Current Air Quality 

II-2-6 

Seasonal Variation

Because photochemical reactions require sunlight to proceed, ozone formation is favored 

by strong solar radiation. Solar radiation is more intense and of longer duration, and 

temperature inversions are stronger and more persistent, in summer than in winter. This 

causes ozone concentrations to be higher in summer than in winter. Peak ozone 

concentrations generally occur near the middle of the day during the period May through 

October. 

Figure 2-4 shows the number of days per month that one or more monitoring stations 

exceeded the federal 8-hour ozone standard level (8-hour average of 0.08 ppm) for the 

period 1985-2005. Up until the late 1980's it was common to have days exceeding the 

federal ozone standard as early as February and as late as November. By the late 1990's 

there were no exceedances in the months of January-February and November-December. 

Also, the frequency of exceedances in early spring and fall has been reduced 

significantly in recent years. 

FIGURE 2-4 

Number of Days Per Month 

Exceeding Federal Ozone Standard in the Basin 

0

5

10

15

20

25

30

35

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Days Exceeding

1985

1990

1995

2000

2005
Chapter2 : Air Quality in the South Coast Air Basin 

II-2-7 

Diurnal Variation

Because time and sunlight are required for precursor organic gases and nitrogen oxides 

to react to form ozone, peak ozone concentrations usually occur from afternoon to early 

evening. By this time, the prevailing sea breeze has moved the polluted air mass miles 

inland from the major sources of precursor emissions. Figure 2-5 illustrates the 

maximum moving 8-hour average ozone concentrations for each hour of the day in the 

Basin for the year 2005 (hours shown are the beginning of the 8-hour period). 

Ozone concentrations in the Basin are typically low during early morning hours, 

increasing rapidly after sunrise and peaking in the afternoon. However, peak 

concentrations occur earlier in the day for coastal areas and later in the day for locations 

further downwind. Examining diurnal variation throughout the District, the time of the 

peak concentration was found to vary from noon - 1 p.m. PST in coastal-central Los 

Angeles county, to 4 - 7 p.m. in the farthest inland Basin and SSAB locations. In the 

mountain area where the Basin's highest concentrations have been recorded in recent 

years, concentrations are usually higher at all times and the peak is reached later in the 

afternoon (around 4 - 5 p.m.) and remains relatively high throughout the evening hours 

during the smog season. The diurnal pattern and occurrence of the peak concentrations 

in these areas serve to depict diurnal formation and impact of ozone transport. 

FIGURE 2-5 

Ozone 

Diurnal Variation, 2005 

Maximum 8-hour Average Concentration for Each Hour in the Basin 

50

75

100

125

150

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

HOUR, PST

Concentration, ppm
Final 2007 AQMP Appendix II: Current Air Quality 

II-2-8 

Day-of-Week Variation

Since the mid-1970s, it has been documented that ozone concentrations in the Basin are 

higher on weekends than on weekdays, in spite of the fact that ozone pollutant 

precursors are lower on weekends than on weekdays. Similar effects have been 

observed in some other metropolitan areas in the nation such as San Francisco, 

Washington D.C., Philadelphia, and New York. 

Figure 2-6 shows the number of station-days exceeding the federal 8-hour ozone 

standard for each day of the week in the Basin for the year 2005. The number of 

exceedances was higher on Sundays, followed by Saturdays. Average ozone 

concentrations also show a pattern similar to the average number of exceedances, with 

weekends tending to be higher than weekdays. The CARB has sponsored several 

research projects to study the causes of elevated ozone levels on weekends in the Basin. 

Changes in daily patterns that impact the quantity and temporal loading of emissions 

have been suggested as strongly contributing to these observations. Carryover of 

matured precursors from weekdays to weekends is also suggested as a contributing 

factor. 

*The term station-days represents the total number of days the standard was exceeded at any 

monitoring station in the Basin. 

FIGURE 2-6 

Ozone 

Day-of-Week Variation, 2005 

Exceedances of the Federal Standard by Day of Week 

Station-Days Exceeding*

0

30

60

90

120

150

Mon Tue Wed Thu Fri Sat Sun
Chapter2 : Air Quality in the South Coast Air Basin 

II-2-9 

SUSPENDED PARTICULATE MATTER 

Total suspended particulate (TSP) is the name applied to the complex mixture of solid 

material suspended in the atmosphere. TSP is collected on a glass fiber filter by means 

of a high volume sampler. Samples are collected for a 24-hour period every sixth day, 

and then returned to the District laboratory for chemical analysis to determine the 

relative concentrations of sulfate, nitrate, and lead. The federal and state standards for 

lead and sulfate are based on analyses of TSP samples. In 2005, TSP samples were 

collected by the District at 12 sites. These samples were analyzed for sulfate, nitrate, 

and lead concentrations. 

The fine fraction of TSP has greater effects on health and visibility than the coarse 

fraction. In 1987 U.S. EPA adopted PM10 standards, which replaced the earlier TSP 

standards. PM10 samples are collected on quartz filters with a size selective inlet high 

volume sampler. The District began PM10 monitoring in late 1984. 

In 1997, the U.S. EPA adopted new federal air quality standards for a subset of fine 

particulate matter, PM2.5, to complement existing PM10 standards that target the full 

range of inhalable particulate matter. In compliance with the adopted standard, the 

District monitored PM2.5 concentrations at 19 sites in 2005. 

PARTICULATE MATTER (PM10) 

Properties

Of greatest concern to public health are the particles small enough to be inhaled into the 

deepest parts of the lung. Respirable particles (particulate matter less than about 10 

micrometers in diameter) can accumulate in the respiratory system and aggravate health 

problems such as asthma, bronchitis, and other lung diseases. Children, the elderly, 

exercising adults, and those suffering from asthma are especially vulnerable to PM10. 

PM10 particles are both directly emitted or formed from diverse emission sources. 

Major sources of directly emitted (primary) PM10 include re-suspended road dust or soil 

entrained into the atmosphere by wind or activities such as construction and agriculture. 

Other components of PM10 form in the atmosphere (secondary PM10) from precursor 

emissions of the gaseous pollutants. 

State PM10 Standard

CARB has revised the state annual PM10 standard effective July 2003. The new 

standard is an annual arithmetic mean of 20 μg/m3

 (changed from annual geometric 

mean of 30 μg/m3

). 
Final 2007 AQMP Appendix II: Current Air Quality 

II-2-10

Current PM10 Air Quality

In 2005, the District measured PM10 concentrations at 20 locations throughout the 

South Coast and Salton Sea Air Basins. Figure 2-7 shows the contour map of the annual 

average (arithmetic mean) PM10 concentrations distribution in the Basin in 2005. The 

areas with the highest annual average PM10 concentrations were located in Riverside 

and San Bernardino counties close to Metropolitan Riverside county. The maximum 

annual average recorded (52.0 μg/m3

 in the Metropolitan Riverside county area) was 103 

percent of the federal standard. 

The federal 24-hour standard was not exceeded anywhere in the District in 2005. The 

maximum 24-hour average concentration (131.0 μg/m3

 recorded in South Coastal Los 

Angeles County area) was 87 percent of the federal 24-hour standard. 

The more stringent state annual standard was exceeded in a much larger area than the 

federal annual standard, with almost all of the Basin and all of the Riverside county 

SSAB recording annual average concentrations above the standard. The state 24-hour 

PM10 standard was also exceeded at most locations monitored in the District. The 

standard was exceeded most frequently in the Basin’s inland valleys, centered on 

Metropolitan Riverside county. 

FIGURE 2-7 

Particulate Matter (PM10) - 2005 

Annual Arithmetic Mean, μg/m3

 
Chapter2 : Air Quality in the South Coast Air Basin 

II-2-11 

The annual arithmetic mean, the percent of days exceeding state and federal standards, 

and the maximum 24-hour average concentration for the years 1990 - 2005 are given in 

Tables A-8 to A-10 in the Attachment. 

Seasonal and Day-of-Week Variation in PM10

PM10 samples are only collected every sixth day (or third day at sites where an intensive 

monitoring schedule has been adopted) and exceedances of the federal standard are 

relatively infrequent in recent years. As a consequence, seasonal and day-of-week 

variations in exceedances of the federal standard for the last few years cannot be 

determined accurately. However, if exceedances of the state standard are considered, 

seasonal and day-of-week patterns do emerge. 

Previous analyses of seasonal variations in PM10 show that the monthly average PM10 

concentration and the monthly average number of days exceeding the state standard tend 

to peak in summer and fall in the inland valley area of the Basin where PM10 

concentrations are highest. However, in the South Coastal Los Angeles county area, 

monthly average PM10 concentrations and the average number of days exceeding the 

state standard are highest in late fall and winter months. 

Figure 2-8 shows the average number of days in each month exceeding the state standard 

at one or more Basin locations over the period 2003-2005. The greatest number of 

exceedances of the state standard occurred in the summer months. Due to the higher 

number of exceedances in the inland valleys, the pattern for the Basin is more similar to 

those for individual sites in the inland valley areas. Figure 2-9 shows the monthly 

average PM10 concentrations for the two sites, Metropolitan Riverside County in inland 

valleys and South Coastal Los Angeles county. In the inland valley areas, PM10 

concentrations are higher in the summer and fall months while in the coastal areas higher 

concentrations are recorded in the late fall and winter months. 

Day-of-week variations have also been examined, and it was found that the average 

weekend concentrations were lower than the weekday average at all sites monitored in 

the Basin and SSAB locations. Figure 2-10 shows the average PM10 concentrations by 

day of week at two representative monitoring sites in the Basin for the period 2003-

2005, based on the Beta Attenuation Monitor (BAM) and Tapered Element Oscillating 

Microbalance (TEOM) data. 

Figure 2-11 shows average PM10 concentrations for each hour of the day for the year 

2005. On average, PM10 concentrations show a peak around 7-8 a.m., the time of the 

heaviest morning traffic rush-hour. 
Final 2007 AQMP Appendix II: Current Air Quality 

II-2-12

FIGURE 2-8 

Basin-Days Exceeding State PM10 Standard by Month, 2003-2005 

FIGURE 2-9 

Monthly Average PM10 Concentration, 2003-2005 

0

2

4

6

8

10

12

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Basin-Days > 50 μg/m3

0

20

40

60

80

100

Jan Feb Mar Apr May Jun Juy Aug Sep Oct Nov Dec

Concentration, ug/m3

Metropolitan Riverside County

South Coastal Los Angeles County
Chapter2 : Air Quality in the South Coast Air Basin 

II-2-13 

20

22

24

26

28

30

Mon Tue Wed Thu Fri Sat Sun

South Coastal Los Angeles County

Concentration, ug/m3

FIGURE 2-10 

Day-of-Week Variation, 2003-2005 

Average PM10 Concentration by Day of Week 

FIGURE 2-11 

Diurnal Variation, 2005 

Average PM10 Concentration for Each Hour of the Day 

40

45

50

55

60

Mon Tue Wed Thu Fri Sat Sun

Metropolitan Riverside County

Concentration, ug/m3

0

10

20

30

40

50

60

70

80

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

HOUR, PST

Concentration, ppm

Basin

Metropolitan Riverside County

South Coastal Los Angeles County
Final 2007 AQMP Appendix II: Current Air Quality 

II-2-14

FINE PARTICULATE MATTER (PM2.5) 

Properties

PM2.5, the fine sized particles less than 2.5 micrometers in diameter, are small enough 

to penetrate the defenses of the human respiratory system and lodge in the deepest 

recesses of the lung, causing potential adverse health impacts. The health effects include 

increased respiratory symptoms and diseases such as ashma, bronchitis, acute and 

chronic respiratory problems like shortness of breath and painful breathing (in children, 

the elderly and sensitive people), and premature deaths (mainly in the elderly due to 

weaker immune systems). Sources of PM2.5 include diesel-powered vehicles such as 

buses and trucks, fuel combustion from automobiles, power plants, industrial processes, 

and wood burning. 

In the Basin, much of the PM10 fraction is actually finer in size than 2.5 micrometers, a 

condition which has major implications for both health and atmospheric visibility. 

Reducing PM2.5 concentrations will therefore not only reduce the threat to the health of 

the Basin's population, but will also improve visual air quality in this region. 

The District began monitoring PM2.5 regularly in 1999. In 2005, the District measured 

PM2.5 concentrations at 19 locations. Samples are collected for a 24-hour period every 

3 days at most locations except for a few sites with high PM2.5 levels where samples are 

taken every day. 

Current PM2.5 Air Quality

Figure 2-12 shows 2005 annual average arithmetic mean PM2.5 concentrations in 

different areas of the Basin. Like PM10, PM2.5 concentrations were higher in the inland 

valley areas of Metropolitan Riverside county. However, PM2.5 concentrations were 

also high in the metropolitan areas of Los Angeles county, mainly due to the secondary 

formation of smaller-sized particulate resulting from mobile and stationary source 

activities. The maximum annual average recorded (21.0 μg/m3

 in the Metropolitan 

Riverside county area) was 139 percent of the federal standard. In 2005, the federal 

annual PM2.5 standard was exceeded at approximately 60 percent of the locations 

monitored in the District. The standard was not exceeded at the coastal areas of Los 

Angeles and Orange counties and the San Bernardino Mountain area in the Basin and 

Coachella Valley area in SSAB. 

The federal 24-hour PM2.5 standard was exceeded at some locations monitored in the 

Basin in 2005. The maximum 24-hour average concentration (132.7 μg/m3

 in East San 

Gabriel Valley) was 203 percent of the federal 24-hour standard. 
Chapter2 : Air Quality in the South Coast Air Basin 

II-2-15 

Figure 2-12 

Fine Particulate Matter (PM2.5) - 2005 

Annual Arithmetic Mean, μg/m3

 

The annual arithmetic mean, the percent of days exceeding the federal standards, the 

maximum 24-hour average concentration, and the 98th percentile concentration for the 

years 1999 - 2005 are given in Tables A-11 to A-15 in the Attachment. 

Seasonal and Day of Week Variation in PM2.5

Seasonal and day-of-week variations in PM2.5 concentrations are complex and location 

dependant, and require further analysis to determine the reasons for the variation. 

Preliminary analysis shows that the PM2.5 concentrations tend to be higher in fall. 

Figure 2-13 shows the average PM2.5 concentration for each month in the Basin for the 

year 2005. 

Preliminary analysis of daily variation shows no specific day-of-week pattern in PM2.5 

concentrations in the Basin. Figure 2-14 shows the total number of days exceeding the 

federal standard in the Basin by day of week for the three-year period 2003-2005. 

Figure 2-15 shows average PM2.5 concentration for each hour of the day for the period 

2003-2005 at two monitoring sites in the Basin. On average, PM2.5 concentrations 

show a peak around 8-9 a.m. 
Final 2007 AQMP Appendix II: Current Air Quality 

II-2-16

FIGURE 2-13 

PM2.5 Seasonal Variation, 2005 

Monthly Average Concentration in the Basin, ug/m3 

FIGURE 2-14 

PM2.5 Day-of-Week Variation, 2003-2005 

Basin-Days Exceeding the Federal Standard by Day of Week 

0

2

4

6

Mon Tue Wed Thu Fri Sat Sun

Basin-Days Exceeding

0

5

10

15

20

25

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Concentration, μg/m3
Chapter 2 Air Quality in the South Coast Air Basin 

II-2-17 

FIGURE 2-15 

Diurnal Variation, 2003-2005 

Average PM2.5 Concentration for Each Hour of the Day 

CARBON MONOXIDE (CO) 

Properties

Carbon monoxide (CO) is a colorless, odorless, relatively inert gas. It is a trace 

constituent in the unpolluted troposphere, and is produced by both natural processes and 

human activities. In remote areas far from human habitation, carbon monoxide occurs in 

air at an average background concentration of 0.04 ppm, primarily as a result of natural 

processes such as forest fires and the oxidation of methane. Global atmospheric mixing 

of CO from urban and industrial sources creates higher background concentrations (up to 

0.20 ppm) near urban areas. The major source of CO in urban areas is incomplete 

combustion of carbon-containing fuels, mainly gasoline. In 2000, 98 percent of the CO 

emitted into the Basin's atmosphere was from mobile sources. Consequently, CO 

concentrations are generally highest in the vicinity of major concentrations of vehicular 

traffic. 

Carbon monoxide is a primary pollutant, meaning that it is directly emitted into the air, 

not formed in the atmosphere by chemical reaction of precursors, as is the case with 

ozone and other secondary pollutants. Ambient concentrations of CO in the Basin 

exhibit large spatial and temporal variations, due to variations in the rate at which CO is 

emitted, and in the meteorological conditions that govern transport and dilution. Unlike 

ozone, CO tends to reach high concentrations in the fall and winter months. The highest 

20

25

30

35

40

45

50

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

HOUR, PST

Concentration, ppm

Metropolitan Riverside County

Central Orange County
Final 2007 AQMP Appendix II: Current Air Quality 

II-2-18

concentrations frequently occur on weekdays at times consistent with rush hour traffic 

and late at night during the coolest, most stable portion of the 24-hour day. 

When carbon monoxide is inhaled in sufficient concentration, it can displace oxygen and 

bind with the hemoglobin in the blood, reducing the capacity of the blood to carry 

oxygen. Individuals most at risk from the effects of CO include heart patients, fetuses 

(unborn babies), smokers, and people who exercise heavily. Normal healthy individuals 

are affected at higher concentrations, which may cause impairment of manual dexterity, 

vision, learning ability, and performance of work. The results of studies concerning the 

combined effects of CO and other pollutants in animals have shown a synergistic 

adverse effect after exposure to CO and ozone. 

Current Carbon Monoxide Air Quality

The District currently monitors carbon monoxide air quality at 25 of its 34 air 

monitoring stations. The highest CO concentrations are found in coastal and central Los 

Angeles county. The highest 8-hour average CO concentration in 2005 (5.9 ppm) was 

recorded in South Central Los Angeles county and was 62 percent of the federal 

standard and 65 percent of the state standard. This was the lowest concentration 

recorded in the Basin since carbon monoxide monitoring began in this region. The 

highest 1-hour average concentration in 2005 (7 ppm) was 19 percent of the federal and 

33 percent of the state 1-hour standards. Concentrations in the less urbanized areas of 

the Basin and in the SSAB were well below the standards. 

In 2005, carbon monoxide standards continued to remain below the standards at all 

locations monitored for the third consecutive year. Highest concentrations were 

recorded in Los Angeles county areas, in the areas of South Central Los Angeles 

County. There have been no exceedances of the stage 1 episode (federal alert) level (8-

hour average CO greater than or equal to 15 ppm) since 1997. Table 1 below shows the 

2005 maximum 

8-hour average carbon monoxide concentrations by Basin and county. 

The annual number of days exceeding the federal carbon monoxide standard at all 

monitoring sites during the period 1990-2005 is given in Table A-16 in the Attachment. 

Tables A-17 and A-18 list the annual number of federal alerts and maximum CO 

concentrations for all sites for the years 1990-2005. 

The District has requested redesignation to attainment for CO, which is pending at the 

time of publication of this report. 
Chapter 2 Air Quality in the South Coast Air Basin 

II-2-19 

TABLE 1 

2005 Maximum 8-Hour Average Carbon Monoxide Concentrations* 

NITROGEN DIOXIDE (NO2) 

Properties 

Nitrogen dioxide (NO2) is a reddish-brown gas with a bleach-like odor. Nitric oxide 

(NO) is a colorless gas, formed from the nitrogen (N2) and oxygen (O2) in air under 

conditions of high temperature and pressure which are generally present during 

combustion of fuels; NO reacts rapidly with the oxygen in air to give nitrogen dioxide 

(NO2). NO2 is responsible for the brownish tinge of polluted urban air. The two gases, 

nitric oxide and nitrogen dioxide, are referred to collectively as oxides of nitrogen 

(NOx). In the presence of sunlight, nitrogen dioxide reacts to give nitric oxide and an 

oxygen atom. The oxygen atom can react further to give ozone, via a complex series of 

chemical reactions involving hydrocarbons (VOCs). Nitrogen dioxide may also react to 

give nitric acid (HNO3) which reacts further to give nitrates, which are a component of 

PM10. 

Nitrogen dioxide is a respiratory irritant and reduces resistance to respiratory infection. 

Children and people with respiratory disease are most susceptible to its effects. 

Current Nitrogen Dioxide Air Quality

In 2005, the District monitored nitrogen dioxide concentrations at 24 locations. Federal 

and state standards for nitrogen dioxide were not exceeded at any location. The federal 

standard has not been exceeded in the Basin since 1991. 

Maximum Percent 

Basin/County 8-Hour Federal Area

 ppm Standard

South Coast Air Basin

Los Angeles 5.9 62% South Central Los Angeles County

Orange 3.3 35% Central Orange County

Riverside 2.5 26% Metropolitan Riverside County

San Bernardino 2.4 25% Central San Bernardino Valley

Salton Sea Air Basin

Riverside 0.8 8% Coachella Valley

 * Federal standard = 9 ppm
Final 2007 AQMP Appendix II: Current Air Quality 

II-2-20

Table 2 shows the 2005 maximum annual average nitrogen dioxide concentrations by 

Basin and county. The maximum annual average nitrogen dioxide concentration 

(0.0313 ppm recorded in the Northwest San Bernardino Valley) was 59 percent of the 

federal standard. Concentrations in the downwind SSAB areas were much lower. The 

maximum 1-hour average concentration in the Basin (0.14 ppm in South Coastal Los 

Angeles County) was 56 percent of the state standard. 

The annual averages, number of days exceeding the state standard, and maximum 1-hour 

average concentrations for each individual area of the District for the years 1990-2005 

are given in Tables A-19 to A-21 in Attachment. 

Though the state and federal standards were not exceeded in 2005, nitrogen dioxide is 

still a concern since it is a precursor to both ozone and particulate matter. Further 

control of oxides of nitrogen will be required to attain the ozone and particulate 

standards. 

TABLE 2 

2005 Maximum Annual Average Nitrogen Dioxide Concentrations* 

Maximum Percent 

Basin/County Annual Avg. Federal Area

 ppm Standard

South Coast Air Basin

Los Angeles 0.0312 58% South Central Los Angeles County;

Ponoma/Walnut Valley

Orange 0.0249 47% North Orange County

Riverside 0.0222 41% Metropolitan Riverside County

San Bernardino 0.0313 59% Northwest San Bernardino Valley

Salton Sea Air Basin

Riverside 0.0120 22% Coachella Valley

 * Federal standard = 0.0534 ppm

SULFUR DIOXIDE (SO2) 

Properties

Sulfur dioxide (SO2) is a colorless gas with a sharp odor. It reacts in the air to form 

sulfuric acid (H2SO4), which contributes to acid precipitation, and sulfates, which is a 

component of PM10 and PM2.5. Most of the SO2 emitted into the atmosphere is 

produced by the burning of sulfur-containing fuels. 
Chapter 2 Air Quality in the South Coast Air Basin 

II-2-21 

At sufficiently high concentrations, sulfur dioxide affects breathing and the lungs’ 

defenses, and can aggravate respiratory and cardiovascular diseases. Asthmatics and 

people with chronic lung disease or cardiovascular disease are most sensitive to its 

effects. Sulfur dioxide also causes plant damage, damage to materials, and acidification 

of lakes and streams. 

Current Sulfur Dioxide Air Quality

In 2005, sulfur dioxide was measured at seven Basin locations. No violations of federal 

or state standards occurred. The federal standards were last exceeded in the 1960’s and 

the state standard was last exceeded in 1990. 

The maximum 24-hour average SO2 concentrations recorded in the District in 2005 are 

shown in Table 3. The highest 24-hour average SO2 concentration (0.012 ppm in East 

San Fernando Valley) was 9 percent of the federal 24-hour standard. The highest 1-hour 

average (0.07 ppm in Central Los Angeles) was 29 percent of the state standard. 

Detailed statistics including annual average and maximum 1-hour average SO2

concentrations for each location monitored for the years 1990-2005 are given in Tables 

A-22 and A-23 in the Attachment. 

While sulfur dioxide concentrations in the Basin no longer exceed standards, SO2 is a 

precursor of PM10 and sulfate. 

TABLE 3 

2005 Maximum 24-Hour Average Sulfur Dioxide Concentrations* 

Maximum Percent 

Basin/County 24-hr Avg. Federal Area

 ppm Standard

South Coast Air Basin

Los Angeles 0.012 9% Southwest Coastal LA County

Orange 0.008 6% North Coastal Orange County

Riverside 0.011 8% Metropolitan Riverside County

San Bernardino 0.004 3% Central San Bernardino Valley

Salton Sea Air Basin

Riverside N.D.

N.D. = No Data. Historical measurements indicate concentrations are below standard.

* Federal standard = 0.14 ppm
Final 2007 AQMP Appendix II: Current Air Quality 

II-2-22

SULFATE (SO4

=

) 

Properties

Sulfates are chemical compounds which contain the sulfate ion (SO4

=

), and are part of 

the mixture of solid materials which make up PM10 and TSP. Most of the sulfates in the 

atmosphere are produced by oxidation of sulfur dioxide. Oxidation of sulfur dioxide 

yields sulfur trioxide (SO3) which reacts with water to give sulfuric acid (H2SO4), which 

contributes to acid precipitation. The reaction of sulfuric acid with basic substances 

such as ammonia yields sulfates, a component of PM10. 

Current Sulfate Air Quality

In 2005 sulfate concentrations were measured at 12 Basin locations. Table 4 shows the 

2005 maximum 24-hour average concentrations in the District by Basin and county. The 

maximum sulfate concentration (17.3 μg/m3

) recorded in the District was 69 percent of 

the state standard. 

The percent of days exceeding the standard and the maximum 24-hour average 

concentration at each monitoring location for the years 1990-2005 are given in Tables 

A-24 and A-25 in the Attachment. 

TABLE 4 

2005 Maximum 24-Hour Average Sulfate Concentrations 

Maximum Percent 

Basin/County 24-hr. Avg. State Area

 μg/m3 Standard

South Coast Air Basin

Los Angeles 17.3 69% South Central LA County

Orange N.D.

Riverside 10.3 41% Metropolitan Riverside County

San Bernardino 10.9 44% Central San Bernardino Valley

Salton Sea Air Basin

Riverside N.D.

N.D. = No Data. Historical measurements indicated concentrations were well below the standard.

* State standard = 25 μg/m3
Chapter 2 Air Quality in the South Coast Air Basin 

II-2-23 

LEAD (Pb) 

Properties

Lead in the atmosphere is present as a mixture of a number of lead compounds. Leaded 

gasoline and lead smelters have been the main Basin sources of lead emitted into the air. 

Due to the phasing out of leaded gasoline, there has been a dramatic reduction in 

atmospheric lead in the Basin over the past two decades. 

Current Lead Air Quality

In 2005 lead concentrations were measured at eight Basin air monitoring stations, and 

they were all well below the standards. Table 5 shows the maximum quarterly average 

lead concentrations in the District by Basin and county in 2005. The maximum 

quarterly average lead concentration (0.03 μg/m3

) was 2 percent of the federal standard. 

TABLE 5 

2005 Maximum Quarterly Average Lead Concentrations 

Maximum Percent 

Basin/County Qtr. Avg.* Federal Area

μg/m3 Standard

South Coast Air Basin

Los Angeles 0.03 2% South Central LA County

Orange N.D. 

Riverside 0.02 1% Metropolitan Riverside County

San Bernardino 0.02 1% Northwest San Bernardino Valley

Salton Sea Air Basin

Riverside N.D.

N.D. = No Data. Historical measurements indicated concentrations were well below the standard.

* Higher concentrations (0.44 μg/m3) were measured in localized areas near sources known to emit lead

 

In addition to lead measurements at District air monitoring stations, special monitoring 

was done in the immediate vicinity of several stationary sources of lead. Data from the 

special monitoring sites showed that higher concentrations were reached in very 

localized areas near sources, with a maximum quarterly average (0.34 μg/m3

) 23 percent 

of the federal standard, and a maximum monthly average (0.44 μg/m3

) 29 percent of the 

state standard. 
Final 2007 AQMP Appendix II: Current Air Quality 

II-2-24

Maximum quarterly average and monthly average lead concentrations at each of the 

regular monitoring sites for the years 1990-2005 are given in Tables A-26 and A-27 in 

the Attachment. 
CHAPTER 3 

AIR QUALITY IN THE RIVERSIDE COUNTY SSAB 

Ozone (O3) 

Particulate Matter (PM10) 

Fine Particulate Matter (PM2.5) 

Carbon Monoxide (CO) 

Nitrogen Dioxide (NO2) 

Sulfur Dioxide (SO2) 

Sulfate (SO4

=

) 

Lead (Pb)

Chapter3 : Air Quality in the Riverside County SSAB 

 II-3-1 

AIR QUALITY IN THE RIVERSIDE COUNTY SSAB 

In 2005, the District monitored air quality at two locations in the Riverside county 

portion of the Salton Sea Desert Air Basin (SSAB), both in the Coachella Valley. One 

monitoring station was located immediately downwind of the densely populated Basin, 

and the other was located further downwind in the Coachella Valley. The maximum 

concentrations recorded at these locations in 2005 are shown in Figure 3-1. Data is 

provided in the tables attached to this appendix. 

In 2005, pollutant concentrations in the Riverside county SSAB exceeded state and 

federal standards for ozone and state standard for PM10. The maximum 1-hour average 

ozone concentration (0.139 ppm) was 139 percent and 111 percent of the state and 

federal standards, respectively. The maximum 8-hour average ozone concentration 

(0.116 ppm) was 155 percent and 136 percent of the 8-hour state and federal ozone 

standards. The maximum annual average PM10 concentration (45.7 μg/m3

) was 223 

percent and 91 percent of the state and federal annual PM10 standards, respectively. 

Federal and state standards for PM2.5, carbon monoxide and nitrogen dioxide were not 

exceeded. The maximum annual average PM2.5 concentration (10.5 μg/m3

) was 69 

percent of 

FIGURE 3-1 

2005 Maximum Pollutant Concentrations as Percent of Standards 

Riverside County SSAB 

Standard

0

50

100

150

200

250

Ozone Ozone PM10 PM2.5 Carbon

Monoxide

Nitrogen

Dioxide

(1-Hour) (8-Hour) (Annual) (Annual) (8-Hour) (Annual)

Coachella Valley

Percent of Standards

State Standard

Federal Standard

Standard

0

50

100

150

200

250

Ozone Ozone PM10 PM2.5 Carbon

Monoxide

Nitrogen

Dioxide

(1-Hour) (8-Hour) (Annual) (Annual) (8-Hour) (Annual)

Coachella Valley

Percent of Standards

State Standard

Federal Standard
Final 2007 AQMP Appendix II: Current Air Quality 

II-3-2

the federal standard. The highest 8-hour average carbon monoxide concentration (0.8 

ppm) was 8 percent of the federal standard. The maximum annual average 

NO2concentration recorded (0.0120 ppm) was 22 percent of the federal NO2 standard. 

No measurements of SO2, sulfate or lead were made in the Riverside county SSAB area 

of the District in 2005. Historical measurements in this area showed concentrations of 

these pollutants to be well below the state and federal standards and monitoring was 

discontinued. 

OZONE (O3) 

Ozone in the atmosphere of the Riverside county portion of SSAB is both directly 

transported from the Basin and formed principally from precursors emitted upwind. 

These precursors are emitted in greatest quantity in the coastal and central Los Angeles 

county areas of the Basin. The Basin’s prevailing sea breeze causes polluted air to be 

transported inland. As the air is being transported inland, ozone is formed, with peak 

concentrations occurring in the inland valleys of the Basin in an area extending from 

eastern San Fernando Valley through the San Gabriel Valley into the Riverside-San 

Bernardino area and the adjacent mountains. As the air is transported still further inland 

into the desert areas, ozone concentrations decrease due to dilution. 

The 1-hour federal ozone standard level was exceeded on four days in Coachella Valley 

in 2005. The more stringent 8-hour federal standard was exceeded on 39 days. Ozone 

concentrations and the number of days exceeding the federal ozone standard are greatest 

in summer. There are typically no exceedances during the winter months. 

The 1-hour and 8-hour state ozone standards were exceeded on 43 days and 69 days, 

respectively, in the Coachella Valley in 2005. The health advisory level has not been 

exceeded in the Coachella Valley area since 1999. No stage 1 episode level has been 

recorded in the Riverside county SSAB area since 1989. 

Figure 3-2 shows the total number of days exceeding federal ozone standards at 

Coachella Valley monitoring sites for the years 1990-2005. 

Number of days exceeding the 1-hour and 8-hour federal ozone standards and episode 

levels and the maximum 1-hour ozone concentrations for the years 1990-2005 are given 

in Tables A-4 through A-7 in the Attachment. 
Chapter3 : Air Quality in the Riverside County SSAB 

 II-3-3 

FIGURE 3-2 

Ozone, 1990-2005 

Number of Days Exceeding Federal Standards in Riverside County SSAB 

PARTICULATE MATTER (PM10) 

Although exceedances of the ozone standard in the Coachella Valley area are due to the 

transport of ozone from the densely populated areas of the Basin upwind, the same 

cannot be said for PM10 exceedances. PM10 exceedances in the Coachella Valley are 

primarily due to locally generated sources of fugitive dust (e.g. construction activities, 

re-entrained dust from paved road travel, and natural wind-blown sources) and not as a 

result of secondary PM10 generated from precursor gaseous emissions. In addition, the 

Riverside county SSAB is subject to frequent high winds which generate wind-blown 

sand and dust, especially from disturbed soil, that can cause high levels of PM10. PM10 

is the only pollutant which has sometimes reached higher concentrations in SSAB than 

in the Basin. 

The federal 24-hour and annual PM10 standard levels were not exceeded in the 

Riverside county part of SSAB in 2005. The maximum 24-hour and annual average 

PM10 concentrations (106 μg/m3

 and 50.2 μg/m3) were 70 percent and 90 percent of the 

standard. 

Days Exceeding

0

20

40

60

80

100

90 92 94 96 98 00 02 04

O3 (8-Hour) O3 (1-Hour)
Final 2007 AQMP Appendix II: Current Air Quality 

II-3-4

The maximum annual average PM10 concentrations in the western portion of the 

Coachella Valley area, as well as the San Gorgonio Pass area at the eastern edge of the 

Basin, remained well below the federal PM10 standards in 2005. 

In 2005, the state 24-hour PM10 standard was exceeded on a maximum of 39 days (34 

percent of sampling days) in the Coachella Valley. The state annual standard was also 

exceeded. The maximum annual average concentration was 223 percent of the state 

standard. 

Annual average, percent number of days exceeding standards, and maximum 24-hour 

average concentrations for the years 1985-2005 for the Riverside county SSAB and 

other District air monitoring stations are presented in the Attachment, in Tables A-8 to 

A-10. 

FINE PARTICULATE MATTER (PM2.5) 

PM2.5 has been measured in Coachella Valley since 1999 when the District began 

PM2.5 monitoring. In 2005, federal PM2.5 standards were not exceeded at either of the 

two Riverside county SSAB air monitoring sites. The maximum 24-hour average and 

annual average concentrations recorded in 2005 (25.0 μg/m3

 and 10.5 μg/m3) were, 

respectively, 38 percent and 70 percent of the federal 24-hour and annual standards. 

CARBON MONOXIDE (CO) 

Carbon monoxide was measured at one of the Riverside county SSAB air monitoring 

stations in 2005. Neither the federal nor state standards were exceeded. The maximum 

8-hour average CO recorded in 2005 (0.8 ppm) was 9 percent of the federal and 8 

percent of the state standards. Historical carbon monoxide air quality and trends in the 

Riverside county SSAB area shows that the area has not exceeded the federal standard 

over the last two decades. 

Summary statistics for carbon monoxide in the Riverside county SSAB as well as other 

District areas are in Tables A-11 to A-12. Table 1 (Chapter 2) shows summary statistics 

for the Basin and SSAB in 2005. 

NITROGEN DIOXIDE (NO2) 

Nitrogen dioxide was measured at one of the stations in the Riverside county SSAB in 

2005. The maximum annual average nitrogen dioxide concentration (0.0120 ppm) was 

22 percent of the federal standard and the maximum 1-hour average (0.10 ppm) was 38 

percent of the state 1-hour standard. 
Chapter3 : Air Quality in the Riverside County SSAB 

 II-3-5 

Table 1 (Chapter 2) and Tables A-14 to A-16 in the Attachment contain NO2 summary 

statistics for the Riverside county SSAB and other District monitoring stations for the 

year 2005 and earlier years. 

SULFUR DIOXIDE (SO2) 

Sulfur dioxide concentrations were not measured in the Riverside county SSAB in 2005. 

Measurements in past years have shown concentrations to be well below the state and 

federal standards. 

Tables A-17 and A-18 in the Attachment contain annual average and maximum 1-hour 

averages for available years for the period 1990-2005 at Riverside county SSAB and 

other District monitoring stations. 

SULFATE (SO4

=

) 

No measurements of sulfate concentrations were made in 2005 at the two monitoring 

stations in the Riverside county SSAB. Historical monitoring has shown concentrations 

to be less than the state standard. 

The percent of days exceeding the standard, and the maximum 24-hour average and 

annual average sulfate concentrations at each monitoring location for past years are 

presented in the Attachment, in Tables A-19 to A-20. 

LEAD (Pb) 

Lead concentrations were not measured at the two Riverside county SSAB stations in 

2005. Measurements in past years have shown concentrations to be less than the state 

and federal standards. 

Maximum quarterly average and monthly average concentrations for past years are given 

in Tables A-21 and A-22 in the Attachment. 
ATTACHMENT 
TABLE A-1 

AMBIENT AIR QUALITY STANDARDS

 CALIFORNIA FEDERAL AIR POLLUTANT CONCENTRATION DISTRICT METHOD PRIMARY (>) SECONDARY (>) Ozone b,c) 0.09 ppm, 1-hour average > 

0.07 ppm, 8-hour average > b)

U.V. Photometry 0.12 ppm, 1-hour average 

0.08 ppm, 8-hour averagec)

Same as Primary Standr

Carbon Monoxide 9.0 ppm, 8-hour average > 

20 ppm, 1-hour average > Gas Correlation 9 ppm, 8-hour average 35 ppm, 1-hour average None 

Nitrogen Dioxide 0.25 ppm, 1-hour average > Gas Phase Chemiluminescence 0.053 ppm, annual average Same as Primary StandrSulfur Dioxide 0.04 ppm, 24-hour average >

0.25 ppm, 1-hour average >

Ultraviolet PulseFluorescence 0.03 ppm, annual average 

0.14 ppm, 24-hour average 

0.50 ppm, 3-hour averag

Particulate Matter (PM10) 

20 μg/m3, annual arithmetic mean > d)50 μg/m3, 24-hour average > 

Size Segregation Inlet High Volume Sampling 

50 μg/m3, annual arithmetic mean 150 μg/m3, 24-hour average 

Same as Primary Standr

 Fine Particulate Matter (PM2.5) 

12 μg/m3, annual arithmetic meane) Inertial Separation and 

Gravimetric Analysis 

15 μg/m3, annual arithmetic mean f) 

65 μg/m3, 24-hour average f)*

Same as Primary Standr

Lead 1.5 μg/m3, 30-day average >= High Vol. Sampling 

Atomic Absorption 

1.5 μg/m3, calendar quarter Same as Primary Standr

Sulfates 25 μg/m3, 24-hour average >= High Vol. Sampling 

Ion Chouromatography 

Hydrogen Sulfide 0.03 ppm, 1-hour average >= Cadmium Hydroxide Stractan Vinyl Chloride 0.010 ppm, 24-hour average >= Gas Chouromatography Visibility Reducing Particles 

In sufficient amount to give an extinction coefficient > 0.23 inverse kilometers (visual range less than 10 miles), with relative humidity <70%, 8-hour average (10am-6pm, PST) . 

Nephelometry and AISI Tape Sampler (COH) 

NO 

FEDERAL 

STANDARDS

a) Reference method as described by the federal government. An equivalent method of measurement may be used as approved by the federal government. 

b) Effective May 17, 2006,new state 8-hour average standard was established. c) Effective September 16, 1997, new federal 8-hour average standard was established. d) Effective July 5, 2003, standard changed from AGM 30 μg/m3 to AAM 20 μg/m3. e) Effective July 5, 2003, new state standard was established. There was no previous state standard for PM2.5. f) Effective September 16, 1997, new federal standards were established. There were no previous standards for PM2.5. * U.S. EPA has recently revised the federal 24-hour PM2.5 standard from 65 μg/m3 to 35 μg/m3. The standard is expected to become effective in December 2006. 
TABLE A-2 

Episode Criteria 

 SCAQMD AND CALIFORNIA FED

AIR POLLUTANT HEALTH ADVISORY (≥) STAGE I (≥) STAGE II (≥) STAGE III (≥) STAGE I (≥) 

(ALERT) 

STA

(WA

Ozone 0.15 ppm, 1-hr. avg. 0.20 ppm, 1-hr. avg. 0.35 ppm, 1-hr. avg. 0.50 ppm, 1-hr. avg. 0.2 ppm, 1-hr. avg. 0.4 ppmCarbon Monoxide 40 ppm, 1-hr. avg. 

20 ppm, 12-hr. avg. 

75 ppm, 1-hr. avg. 

35 ppm, 12-hr. avg. 

100 ppm, 1-hr. avg. 50 ppm, 12-hr. avg. 

15 ppm, 8-hr. avg. 30 ppm

Nitrogen Dioxide 0.6 ppm, 1-hr. avg.

0.15 ppm, 24-hr. avg 

1.2 ppm

0.30 ppm

Sulfur Dioxide 0.50 ppm, 1-hr. avg.

0.20 ppm, 24-hr. avg.

1.00 ppm, 1-hr. avg. 

0.70 ppm, 24-hr. avg.

2.00 ppm, 1-hr. avg. 

0.90 ppm, 24-hr. avg. 

0.3 ppm, 24-hr. avg. 0.6 ppm

Particulate Matter (PM10) 

 350 μg/m3, 24-hr. avg. 420 μg/m

Fine Particulate Matter (PM2.5) Sulfates* 25 μg/m3, 24-hr. avg. combined with ozone > 0.20 ppm, 1-hr. avg. Actions to be Taken** Health Advisory to 

a) Persons with respiratory and coronary disease, b) School officials in order to curtail students' participation in strenuous activities. 

First steps in abatement plans. Health Advisory to a) Persons with respiratory and coronary disease, b) School officials in order to curtail students' participation in strenuous activities.

Intermediate Steps. Abatement actions taken to reduce concentration of pollutant at issue. 

Mandatory abatement measures. Extensive actions taken to prevent exposure at indicated levels. State can take action if local efforts failed. 

Open burning prohibited. Reduction in vehicle operation requested. Industrial curtailment. 

Incineratoprohibitedin vehicle required. industrial 

 * Episodes based upon these criteria are not classified according to stages. ** For ozone, actions a) and b) are taken at Health Advisory level. For all other pollutants, these actions are taken at Stage I Episode level.
TABLE A-3 

Air Monitoring Stations and Source/Receptor Areas 

 SOURCE/RECEPTOR 

AREA # AREA* STN #

 

LOS ANGELES COUNTY

 1 Central LA 087

 2 Northwest Coastal LA County 091

 3 Southwest Coastal LA County 820

 4 South Coastal LA County 1 072

 4 South Coastal LA County 2 077

 6 West San Fernando Valley 074

 7 East San Fernando Valley 069

 8 West San Gabriel Valley 088

 9 East San Gabriel Valley 1 060

 9 East San Gabriel Valley 2 591

 10 Pomona/Walnut Valley 075

 11 South San Gabriel Valley 085

 12 South Central LA County 1 084

 12 South Central LA County 2 801

 13 Santa Clarita Valley 090

ORANGE COUNTY

 16 North Orange County 3177

 17 Central Orange County 3176

 18 North Coastal Orange County 3195

 19 Saddleback Valley 1 3186

 19 Saddleback Valley 2 3812

RIVERSIDE COUNTY

 22 Norco/Corona 4155

 23 Metropolitan Riverside County 1 4144

 23 Metropolitan Riverside County 2 4146

 23 Mira Loma 5212

 24 Perris Valley 4149

 25 Lake Elsinore Area 4158

 29 Banning Airport 4164

 30 Coachella Valley 1** 4137

 30 Coachella Valley 2** 4157

SAN BERNARDINO COUNTY

 32 Northwest San Bernardino Valley 5175

 33 Southwest San Bernardino Valley 5817

 34 Central San Bernardino Valley 1 5197

 34 Central San Bernardino Valley 2 5203

 35 East San Bernardino Valley 5204

 37 Central San Bernardino Mountains 5181

 38 East San Bernardino Mountains 5818

* Source/Receptor areas and numbers are shown in detail on the map "South Coast Air Quality Management 

 District and Air Monitoring Areas" which is available from SCAQMD Public Information. 

**Salton Sea Air Basin. 
FIGURE A-1 

South Coast Air Basin and Adjoining Areas of Salton Sea Air Basin 

Los Angeles County

Orange County

San Bernardino Coun

Riverside County

M I LES

0 25

19

21

25

22

26

24

23

32

36

37 

20

18

33

34

35

17

4

16

10 11

5

1

2

3

9

8 6 7

12

13 15

14

##

SOUTH C OASTAIR BASIN (SCAB)COUNTY LINESAREA LINESAIR MONITORINGSTATIONAREA NUMBER

APR IL 1995 VERSION

SCAQMDAIR MONITORING NETWORK
TABLE A-4 

Ozone - Number of Days Exceeding the Federal Standard *** 

 (0.08 ppm, 8-Hour Average) 

STN# LOCATION 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 LOS ANGELES COUNTY:  060 East San Gabriel Valley 1 89 71 95 90 82 71 39 18 23 9 16 18  069 East San Fernando Valley 50 58 67 21 23 31 11 6 14 3 11 5  072 South Coastal Los Angeles County 0 1 8 1 2 0 1 0 0 0 0 0  074 West San Fernando Valley 76 75 52 47 35 22 29 3 13 1 0 7  075 Pomona/Walnut Valley 1 61 62 61 57 60 56 23 10 21 10 5 3  084 South Central Los Angeles County 1 1 3 5 0 1 0 0 0 0 0 0 0  085 South San Gabriel Valley 2 4 2  087 Central Los Angeles 35 26 27 11 23 10 7 3 9 2 4 1  088 West San Gabriel Valley 80 76 81 62 67 55 27 16 17 4 14 9  090 Santa Clarita Valley 84 92 100 59 96 50 46 27 35 13 15 27  091 Northwest Coastal Los Angeles County 10 14 10 9 5 1 4 2 0 0 0 0  094 Southwest Coastal Los Angeles County 1 1 0 0  820 Southwest Coastal Los Angeles County 2 -- -- -- -- -- -- -- -- -- -- -- -- 

 591 East San Gabriel Valley 2 107 100 125 104 104 87 53 26 38 8 22 31 ORANGE COUNTY: 

3176 Central Orange County 1 8 13 23 7 7 1 1 1 4 0 1 0 3177 North Orange County 37 34 33 22 15 9 6 3 4 1 4 2 3186 Saddleback Valley 1 0 2* -- 3195 North Coastal Orange County 5 5 6 1 0 0 0 0 0 0 2 0 3812 Saddleback Valley 2 -- -- -- -- -- -- -- -- -- -- 8* 2 RIVERSIDE COUNTY: 4137 Coachella Valley 1** 21 33 42 4141 Hemet/San Jacinty Valley -- -- -- -- -- 

4144 Metropolitan Riverside County 112 109 115 102 114 83 74 55 57 27 28 34 4149 Perris Valley 85 97 118 106 101 76 68 41 28 7 40 58 4150 Banning/San Gorgonio Pass 55 42 29 16 34 19 18 7 2 a) -- -- 4155 Norco/Corona -- -- -- -- -- 

4157 Coachella Valley 2** 7 9 17 4158 Lake Elsinore 61 66 60 56 84 54 43 39 44 37 30 46 4163 Temecula Valley -- -- -- -- -- -- 4164 Banning Airport -- -- -- -- -- -- -- -- -- 33 39 49 SAN BERNARDINO COUNTY: 5175 Northwest San Bernardino Valley 71 70 102 74 91 82 57 30 40 17 18 33 5181 Central San Bernardino Mountains 132 131 148 133 136 93 98 71 90 87 66 74 5197 Central San Bernardino Valley 1 105 90 117 84 104 73 62 33 43 16 15 31 5203 Central San Bernardino Valley 2 103 97 119 88 118 87 89 65 50 31 26 39 5204 East San Bernardino Valley 1 106 125 138 142 121 96 91 79 60 39 50 52 

District Maximum 132 131 148 142 136 96 98 79 90 87 66 74 

 * Less than 12 full months of data  ** Salton Sea Air Basin *** Refer to 2003 AQMP for 1976 to 1989 data
TABLE A-5 

Ozone - Number of Days Exceeding the Federal Standard *** 

 (0.12 ppm, 1-Hour Average) 

STN# LOCATION 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 LOS ANGELES COUNTY:  060 East San Gabriel Valley 1 84 73 91 79 72 63 26 11 19 2* 11 9  069 East San Fernando Valley 40 55 47 16 18 20 6 2 7 0 3 2  072 South Coastal Los Angeles County 0 0 6 1 1 0 0 0* 0 1 0 0  074 West San Fernando Valley 41 53 25 32 7 8 11 0 7 0 0 2  075 Pomona/Walnut Valley 1 60 60 56 45 47 47 16 7 18 2 3 1  084 South Central Los Angeles County 1 3 1 4 0 0 0 1 0 0 0 0 0  085 South San Gabriel Valley 43 48 45 33 21 20 32 6 10 0 2 1  087 Central Los Angeles 32 23 23 8 14 5 24 0 5 1 1 0  088 West San Gabriel Valley 69 70 71 53 61 44 54 5 14 0 7 1  090 Santa Clarita Valley 62 65 71 44 66 26 68 13 16 0 1 9  091 Northwest Coastal Los Angeles County 8 9 12 7 2 1 13 0 1 0 0 0  094 Southwest Coastal Los Angeles County 1 0 0 1 1 0 0 1 0 0 1 0 0  820 Southwest Coastal Los Angeles County 2 -- -- -- -- -- -- -- -- -- -- -- --  591 East San Gabriel Valley 2 103 91 118 96 88 73 49 18 28 3 11 13 ORANGE COUNTY: 3176 Central Orange County 1 11 11 22 3 5 2 1 0 2 0* 1 0* 3177 North Orange County 35 28 31 13 9 4 5 1 5 0 1 0 3186 Saddleback Valley 1 11 10 9 7 5 1 2 2 2 0 1* -- 3195 North Coastal Orange County 3 5 3 1 0 0 1 0 0 0 0 0 3812 Saddleback Valley 2 -- -- -- -- -- -- -- -- -- -- 2* 1 RIVERSIDE COUNTY: 4137 Coachella Valley 1** 27 22 21* 20 13 9 12 4* 8 1 0 6 4141 Hemet/San Jacinty Valley 20 23 5 8 13 2 0* -- -- -- -- -- 4144 Metropolitan Riverside County 90 79 75 71 77 52 36 13* 32 3 3 7 4149 Perris Valley 62 71 83 73 59 36 31 6 8 0 15 19 4150 Banning/San Gorgonio Pass 43 31 19 8 25 15 11 2 0* a) -- -- 4155 Norco/Corona 13 54 16 17 14 23 2* -- -- -- -- -- 4157 Coachella Valley 2** 10 13 8 3 0 3 0 0 2 1 0 0 4158 Lake Elsinore 36 45 24 27 27 23 17 4 22 5 1 12 4163 Temecula Valley -- -- 2 1 0* 0 0* 0* -- -- -- -- 4164 Banning Airport -- -- -- -- -- -- -- -- 25 5 4 16 SAN BERNARDINO COUNTY: 5175 Northwest San Bernardino Valley 64 67 81 55 79 67 35 12 30 4 10 14 5181 Central San Bernardino Mountains 103 90 103 88 107 65 62 29 57 30 17 26 5197 Central San Bernardino Valley 1 92 74 88 65 91 57 38 10 32 4 7 13 5203 Central San Bernardino Valley 2 78 79 85 65 96 61 63 32 39 14 7 18 5204 East San Bernardino Valley 1 81 91 103 95 98 69 65 35 43 12 11 21* 

District Maximum 103 91 118 96 107 73 68 35 57 30 17 26 

 * Less than 12 full months of data  ** Salton Sea Air Basin *** Refer to 2003 AQMP for 1976 to 1989 data
TABLE A-6 

Ozone - Number of Days of First/Second Stage Episodes *** 

(Days Maximum 1-Hour Average Ozone ≥ 0.20 ppm/≥ 0.35 ppm) 

STN# LOCATION 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001  060 East San Gabriel Valley 1 13/0 12/0 16/0 11/0 2/0 3/0 1/0 0/0 1/0 0/0* 0/0 0/0  069 East San Fernando Valley 1/0 4/0 8/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0  072 South Coastal Los Angeles County 0/0 0/0 0/0 0/0 0/0 0/0 0/0* 0/0 0/0 0/0 0/0 0/0  074 West San Fernando Valley 0/0 2/0 0/0 0/0 0/0 0/0 1/0 0/0 0/0 0/0 0/0 0/0  075 Pomona/Walnut Valley 1 12/0 8/0 10/0 6/0 3/0 2/0 0/0 0/0 0/0 0/0 0/0 0/0  084 South Central Los Angeles County 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0  085 South San Gabriel Valley 0/0 6/0 5/0 0/0 2/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0  087 Central Los Angeles 2/0 0/0 1/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0  088 West San Gabriel Valley 7/0 10/0 10/0 5/0 2/0 1/0 0/0 0/0 0/0 0/0 0/0 0/0  090 Santa Clarita Valley 6/0 8/0 4/0 3/0 6/0 1/0 0/0 0/0 0/0 0/0 0/0 0/0  091 Northwest Coastal Los Angeles County 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0  094 Southwest Coastal Los Angeles County 1 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0  820 Southwest Coastal Los Angeles County 2 -- -- -- -- -- -- -- -- -- -- -- -- 

 591 East San Gabriel Valley 2 29/0 34/0 30/0 19/0 10/0 9/0 2/0 0/0 3/0 0/0 0/0 0/0 3176 Central Orange County 1 0/0 2/0 1/0 0/0 1/0 0/0 0/0 0/0 0/0 0/0* 0/0 0/0* 

3177 North Orange County 4/0 1/0 1/0 0/0 2/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 3186 Saddleback Valley 1 0/0 1/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0* -- 3195 North Coastal Orange County 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 3812 Saddleback Valley 2 -- -- -- -- -- -- -- -- -- -- 4137 Coachella Valley 1** 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0* 0/0 0/0 0/0 0/0 4141 Hemet/San Jacinty Valley 1/0 0/0 0/0 0/0 0/0 0/0 0/0* -- -- -- -- -- 4144 Metropolitan Riverside County 15/0 17/0 6/0 5/0 2/0 3/0 1/0 0/0* 1/0 0/0 0/0 0/0 4149 Perris Valley 0/0 5/0 1/0 3/0 0/0 1/0 0/0 0/0 0/0 0/0 0/0 0/0 4150 Banning/San Gorgonio Pass 4/0 1/0 0/0 0/0 1/0 0/0 0/0 0/0 0/0* -- -- -- 4155 Norco/Corona 0/0 7/0 1/0 0/0 0/0 0/0 0/0 -- -- -- -- -- 4157 Coachella Valley 2** 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 4158 Lake Elsinore 0/0 1/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 0/0 4163 Temecula Valley -- -- 0/0 0/0 0/0* 0/0 0/0* 0/0* -- -- -- -- 5175 Northwest San Bernardino Valley 12/0 14/0 15/0 7/0 7/0 6/0 2/0 0/0 1/0 0/0 0/0 0/0 5181 Central San Bernardino Mountains 16/0 15/0 22/0 5/0 12/0 6/0 4/0 1/0 10/0 0/0 0/0 0/0 5197 Central San Bernardino Valley 1 20/0 16/0 19/0 5/0 9/0 2/0 1/0 0/0 1/0 0/0 0/0 0/0 5203 Central San Bernardino Valley 2 8/0 9/0 17/0 4/0 7/0 4/0 2/0 1/0 1/0 0/0 0/0 0/0 5204 East San Bernardino Valley 1 11/0 16/0 7/0 8/0 8/0 4/0 1/0 1/0 1/0 0/0 0/0 0/0* 

 * Less than 12 full months of data  ** Salton Sea Air Basin *** Refer to 2003 AQMP for 1976 to 1989 data
TABLE A-7 

Ozone - Annual Maximum 1-Hour, ppm*** 

LOCATION 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1

087 Central Los Angeles .34 .21 .30 .31/ .29 .32 .40 .26 .29 .30 .22 060 East San Gabriel Valley 1 .38 .32 .40 .45 .41 .35 .36 .39 .31 .36 .31 

069 East San Fernando Valley .35 .31 .30 .39 .35 .27 .25 .31 .26 .30 .28 

091 Northwest Coastal Los Angeles County .28 .18/ .24/ .26 .21 .23 .28 .23 .27/ .27 .20 

072 South Coastal Los Angeles County .16 .15 .19 .21 .20 .23 .22 .30 .27 .23 .18 074 West San Fernando Valley .27 .34 .27 .33 .38 .25 .22 .26 .26 .25 .22 

075 Pomona/Walnut Valley 1 .36 .32 .41 .35 .37 .33 .31 .34 .31 .33 .27 

094 Southwest Coastal Los Angeles County -- -- -- -- -- -- -- -- -- -- .19 

820 Southwest Coastal Los Angeles County -- -- -- -- -- -- -- -- -- -- -- 

090 Santa Clarita Valley .33 .33 .42 .44 .41 .33 .37/ .34 .30 .37 .26 088 West San Gabriel Valley .34 .32 .32 .32 .36 .29 .26/ .29 .27 .24 .24 

084 South Central Los Angeles County 1 .24 .24 .18 .29 .18 .21 .26 .23 .27 .21 .20 

085 South San Gabriel Valley .35 .32 .43 .39 .39 .35 .39 .33 .27 .31 .24 

591 East San Gabriel Valley 2 -- -- -- -- .49 .39 .36 .38 .34 .39 .35 

3176 Central Orange County 1 .30 .19 .29 .33 .28 .26 .26 .30 .25 .25 .20 3177 North Orange County 1 .30 .25 .35 .38 .31 .27 .32 .27 .32 .34 .25 

3195 North Coastal Orange County .16 .18 .22 .21/ .16 .20 .18 .25 .25 .21 .17 

3186 Saddleback Valley 1 .23 .20 .34 .32 .34 .33 .27 .29 .30 .28 .23 

3812 Saddleback Valley 2 -- -- -- -- -- -- -- -- -- -- -- 

4137 Coachella Valley 1** .22 .21 .20 .24 .21 .19 .19 .19 .20 .24 .18 4157 Coachella Valley 2** .16 .19 .17 .21 .11 .18 .17 .18 .19 .20 -- 

4155 Norco/Corona .33 .36 .40 .33/ .34 .37 .35 .35 .30 .35 .27 

4141 Hemet/San Jacinto Valley .19 .25 .27 -- -- -- -- -- .18* .23 .18 

4144 Metropolitan Riverside County 1 .36 .35 .39 .34 .37 .30 .31 .36 .32 .35 .25 

4149 Perris Valley .22 .28 .32 .25 .29 .24 .28 .26 .22 .29 .22 

4150 San Gorgonio Pass .28 .27 .30 .27 .26 .23 .24 .26 .25 .29 .22 

4164 BanningAirport -- -- -- -- -- -- -- -- -- -- -- 

4163 Temecula Valley .21 .17 .23 -- -- -- -- -- -- -- -- 

4158 Lake Elsinore .20 .23 .30 -- -- -- -- -- -- -- -- 

5203 Central San Bernardino Valley 2 .32 .37 .36 .34 .36 .36/ .30 .32 .30 .27/ .30 5204 East San Bernardino Valley .35 .33 .39 .34/ .32 .24 .29 .30 .29 .33/ .29 

5175 Northwest San Bernardino Valley -- -- -- -- -- -- -- .36 .32 .33 .29 

5197 Central San Bernardino Valley 1 .38 .39 .42 .42 .42 .35/ .31 .32 .32 .34 .31 

5181 Central San Bernardino Mountains 1 .23 .32 .33 .40 .31 .35 .32 .28 .34 .30 .26 

 District Maximum .38 .39 .43 .45 .49 .39 .40 .39 .34 .39 .35 

 * Less than 12 full months of data. / Station location change 

 ** Salton Sea Air Basin *** Refer to 2003 AQMP for 1955 to 1975 data
TABLE A-7 (continued) 

Ozone - Annual Maximum 1-Hour, ppm*** 

LOCATION 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 

087 Central Los Angeles .20 .19 .20 .16 .19 .17 .14 .12 .15 .13 .14 .12 060 East San Gabriel Valley 1 .23 .28 .27 .24 .25 .21 .20 .16 .20 .14 .17 .19 

069 East San Fernando Valley .20 .22 .22 .18 .17 .17 .14 .13 .18 .12 .15 .13 

091 Northwest Coastal Los Angeles County .16 .18 .17 .18 .16 .14 .14 .11 .13 .12 .10 .10 

072 South Coastal Los Angeles County .12 .11 .15 .14 .16 .11 .11 .10 .12 .13 .12 .09 

074 West San Fernando Valley .19 .22 .17 .19 .14 .15 .21 .12 .16 .10 .11 .14 

075 Pomona/Walnut Valley 1 .24 .24 .26 .21 .24 .22 .19 .16 .18 .14 .15 .14 

094 Southwest Coastal Los Angeles County .10 .11 .15 .13 .11 .12 .13 .11 .09 .15 .10 .10 

820 Southwest Coastal Los Angeles County -- -- -- -- -- -- -- -- -- -- -- -- 088 West San Gabriel Valley .26 .23 .27 .22 .26 .21 .17 .14 .17 .12 .16 .16 

090 Santa Clarita Valley .23 .24 .22 .22 .26 .21 .17 .16 .18 .12 .13/ .18 

084 South Central Los Angeles County 1 .15 .16 .17 .12 .12 .09 .10 .08 .09 .12 .09 .08 

085 South San Gabriel Valley .19 .26 .26 .19 .22 .18 .14 .13 .18 .12 .14 .13 

591 East San Gabriel Valley 2 .29 .32 .30 .28 .30 .22 .21 .17 .22 .14 .17 .19 

3176 Central Orange County 1 .18 .25 .22 .17 .21 .13 .13 .10 .11 .10* .13 .11 3177 North Orange County 1 .21 .21 .21 .19 .25 .16 .15 .13 .18 .12 .14 .11 

3195 North Coastal Orange County .15 .17 .15 .13 .12 .11 .10 .10 .12 .10 .10 .10 

3186 Saddleback Valley 1 .19 .24 .16 .16 .18 .15 .14 .13 .16 .10 .13 -- 

3812 Saddleback Valley 2 -- -- -- -- -- -- -- -- -- -- .15 .13 

4137 Coachella Valley 1** .17 .18 .15* .17 .17 .16 .16 .16 .17 .13 .12 .14 4157 Coachella Valley 2 ** .16 .18 .14 .16 .12 .14 .12 .11 .13 .13 .11 .11 

4155 Norco/Corona .17 .22 .23 .16 .17 .19 .16 -- -- -- -- -- 4141 Hemet/San Jacinto Valley .22 .19 .15 .18 .16 .15 .12 -- -- -- -- -- 

4144 Metropolitan Riverside County .29 .24 .26 .26 .25 .21 .20 .19 .20 .14 .14 .14 

4149 Perris Valley .19 .20 .21 .20 .18 .20 .18 .14 .15 .11 .16 .15 

4150 San Gorgonio Pass .22 .20 .16 .16 .20 .18 .19 .13 .12/ -- -- -- 

4164 Banning Airport -- -- -- -- -- -- -- -- .17 .14 .14 .15 

4163 Temecula Valley -- .17* .13 .13 .10* .11 .10 .10* -- -- -- -- 

4158 Lake Elsinore .19 .20 .17 .19 .19 .19 .15 .16 .17 .14 .13 .15 

5203 Central San Bernardino Valley 2 .29 .25 .28 .21 .25 .20 .24 .20 .21 .16 .15 .18 5204 East San Bernardino Valley .30 .25 .27 .27 .23 .24 .22 .20 .22 .15 .15 .17* 

5175 Northwest San Bernardino Valley .29 .27 .28 .24 .25 .24 .22 .19 .21 .15 .18 .17 

5197 Central San Bernardino Valley 1 .27 .29 .28 .24 .25 .22 .22 .17 .20 .14 .17 .17 

5181 Central San Bernardino Mountains 1 .33 .27 .28 .24 .27 .26 .20 .21 .24 .17 .18 .17 

 District Maximum .33 .32 .30 .28 .30 .26 .24 .21 .24 .17 .18 .19 

 * Less than 12 full months of data. / Station location change  ** Salton Sea Air Basin *** Refer to 2003 AQMP for 1955 to 1975 data 
TABLE A-8 

Particulate Matter (PM10) 

Annual Arithmetic Mean, μg/m3*** 

STN# LOCATION 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 LOS ANGELES COUNTY:  060 East San Gabriel Valley 1 55 66 47 43 44 49 45 46 41 56 46 45  069 East San Fernando Valley 52 55 49 45 38 42 42 45 36 44 39 41  072 South Coast Los Angeles County 1 44 40 39 37 40 39 35 41 32 39 38 37  077 South Coast Los Angeles County 2 -- -- -- -- -- -- -- -- -- -- -- -- 

 087 Central Los Angeles 53 57 48 47 45 43 41 43 37 45 40 44 

 090 Santa Clarita Valley 43 47 35 33 36 37 33 33 30 38 33 32  094 Southwest Coastal Los Angeles County 1 41 39 33 37 36 36 33 36 33 36 36 37  820 Southwest Coastal Los Angeles County 2 -- -- -- -- -- -- -- -- -- -- -- -- 

ORANGE COUNTY: 

3176 Central Orange County 1 49 45 40 38 37 44 35 39 36 49 40 36 3186 Saddleback Valley 1 43 37 34 34 33 38 30 35 31 37 29 -- 3812 Saddleback Valley 2 -- -- -- -- -- -- -- -- -- 29 28 26 RIVERSIDE COUNTY: 4137 Coachella Valley 1** 35 43 30 27 28 27 29 26 26 29 24 27 4144 Metropolitan Riverside County 1 78 76 63 72 66 69 61 65 56 72 60 63 4149 Perris Valley 59 49 45 50 45 47 40 45 38 50 41 41 4150 San Gorgonio Pass 35 38 34 33 35 30 34 38 28 -- -- -- 4155 Norco/Corona -- -- -- 53 53 54 44 50 47 55 49 -- 4157 Coachella Valley 2** 79 69 43 46 49 52 51 49 48 53 52 50 4163 Temecula Valley -- 38 31 27 22 -- -- -- -- -- -- -- 4164 Banning Airport -- -- -- -- -- -- -- -- 27 35 29 35 SAN BERNARDINO COUNTY: 5171 Southwest San Bernardino Valley 1 72 68 79 58 50 54 51 51 47 55 -- -- 5181 Central San Bernardino Mountains 37 39 33 31 26 20 24 24 25 27 24 -- 5197 Central San Bernardino Valley 1 78 63 56 57 60 61 55 54 50 60 53 51 5203 Central San Bernardino Valley 2 65 61 57 56 54 57 53 51 46 57 50 52 5204 East San Bernardino Valley -- -- -- 45 47 48 46 43 41 47 46 47 5817 Southwest San Bernardino Valley 2 -- -- -- -- -- -- -- -- -- 66 50 52 

District Maximum 79 76 79 72 66 69 61 65 56 72 60 63 

 * Less than 12 full months of data.  ** Salton Sea Air Basin *** Refer to 2003 AQMP for 1985 to 1989 data 
TABLE A-9 

Particulate Matter (PM10) - Percent of Sampling Days 

Exceeding State Standard (50 μg/m3) 

And Federal Standard (150 μg/m3)*** 

STN# LOCATION 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 LOS ANGELES COUNTY:  060 East San Gabriel Valley 1 50/0 68/0 39/0 32/0 40/0 40/2 41/0 40/0 28/0 58/0 42/0 38/0  069 East San Fernando Valley 47/2 50/0 31/3 36/0 18/0 25/0 25/0 30/0 15/0 35/0 23/0 23/0 

 072 South Coast Los Angeles County 1 24/0 24/0 19/0 20/0 18/0 19/0 15/0 18/0 10/0 22/0 21/0 17/0 

 077 South Coast Los Angeles County 2 -- -- -- -- -- -- -- -- -- -- -- -- 

 087 Central Los Angeles 52/2 54/2 36/0 43/0 33/0 23/0 18/0 25/0 17/0 33/0 25/0 33/0 

 090 Santa Clarita Valley 28/0 23/0 9/0 15/0 18/0 14/0 9/0 9/0 6/0 21/0 7/0 7/0 

 094 Southwest Coastal Los Angeles County 1 26/0 42/0 13/0 15/0 22/0 21/0 8/0 7/0 12/0 10/0 16/0 14/0  820 Southwest Coastal Los Angeles County 2 -- -- -- -- -- -- -- -- -- -- -- -- 

ORANGE COUNTY: 

3176 Central Orange County 1 34/2 24/0 20/0 21/0 18/0 23/2 10/0 18/0 20/0 39/0 13/0 20/0 3186 Saddleback Valley 1 29/0 15/0 8/0 12/0 12/0 18/0 7/0 7/0 10/0 10/0 3/0 -- 

3812 Saddleback Valley 2 -- -- -- -- -- -- -- -- -- 3/0 3/0 5/0 RIVERSIDE COUNTY: 

4137 Coachella Valley 1** 15/0 25/2 7/2 2/0 3/0 4/0 3/0 2/0 5/0 5/0 0/0 2/0 4144 Metropolitan Riverside County 1 75/5 68/3 64/0 69/7 67/2 62/7 68/2 70/2 54/0 72/2 70/0 67/0 

4149 Perris Valley 53/5 43/0 41/0 45/0 43/0 38/0 33/0 32/0 26/0 50/0 22/0 27/0 

4150 San Gorgonio Pass 20/0 30/0 17/0 18/0 23/0 12/0 19/0 25/0 9/0 -- -- -- 

4155 Norco/Corona -- -- -- 51/2 58/0 47/3 33/0 42/2 40/0 55/0 48/0 33/0 4157 Coachella Valley 2** 70/7 63/5 31/0 41/0 38/0 44/2 50/0 43/0 40/0 54/0 50/0 45/0 

4163 Temecula Valley -- 21/0 4/0 3/0 0/0 -- -- -- -- -- -- -- 

4164 Banning Airport -- -- -- -- -- -- -- -- 4/0 12/0 8/0 13/2 SAN BERNARDINO COUNTY: 

5171 Southwest San Bernardino Valley 1 63/7 67/2 66/3 62/0 44/0 51/5 53/0 36/2 34/0 56/0 -- -- 5181 Central San Bernardino Mountains 19/0 13/0 8/0 4/0 5/0 2/0 0/0 0/0 0/0 0/0 0/0 -- 

5197 Central San Bernardino Valley 1 73/5 65/0 59/0 57/0 63/0 57/3 57/0 48/0 47/0 61/0 52/0 57/0 

5203 Central San Bernardino Valley 2 58/3 68/2 60/0 63/0 51/0 53/0 58/0 45/0 38/0 56/0 53/0 52/0 

5204 East San Bernardino Valley -- -- -- 46/0 41/0 41/2 42/0 38/0 32/0 40/0 44/0 45/0 5817 Southwest San Bernardino Valley 2 -- -- -- -- -- -- -- -- -- 67/2 45/0 42/2 

 * Less than 12 full months of data.  ** Salton Sea Air Basin *** Refer to 2003 AQMP for 1985 to 1989 data 
TABLE A-10 

Particulate Matter (PM10) 

Annual Maximum 24-Hour Average, μg/m3*** 

STN# LOCATION 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 LOS ANGELES COUNTY:  060 East San Gabriel Valley 1 127 137 107 101 127 157 100 116 87 103 94 106  069 East San Fernando Valley 161 133 222 93 114 135 110 92 75 82 74 86  072 South Coast Los Angeles County 1 119 92 67 86 97 146 113 87 69 79 105 91  077 South Coast Los Angeles County 2 -- -- -- -- -- -- -- -- -- -- -- --  087 Central Los Angeles 152 151 137 104 122 141 138 102 80 88 80 97  090 Santa Clarita Valley 93 81 84 75 66 87 91 67 60 75 64 62  094 Southwest Coastal Los Angeles County 1 127 79 67 91 81 136 107 79 66 69 74 75  820 Southwest Coastal Los Angeles County 2 -- -- -- -- -- -- -- -- -- -- -- -- 

ORANGE COUNTY: 

3176 Central Orange County 1 158 146 88 92 106 172 101 91 81 122 126 93 3186 Saddleback Valley 1 88 94 83 115 91 122 79 86 70 111 60 -- 3812 Saddleback Valley 2 -- -- -- -- -- -- -- -- -- 56 98 60 RIVERSIDE COUNTY: 4137 Coachella Valley 1** 83 197 175 58 55 68 130 63 72 104 44 53 4144 Metropolitan Riverside County 1 207 179 126 231 161 219 162 163 116 153 139 136 4149 Perris Valley 250 113 115 131 112 145 87 139 98 112 87 86 4150 San Gorgonio Pass 89 87 89 87 96 138 122 227 76 -- -- -- 4155 Norco/Corona -- -- -- 164 139 177 94 158 93 136 129 109 4157 Coachella Valley 2** 520 340 117 125 97 199 117 144 114 119 114 149 4163 Temecula Valley -- 66 88 105 48 -- -- -- -- -- -- -- 4164 Banning Airport -- -- -- -- -- -- -- -- 62 86 69 219 SAN BERNARDINO COUNTY: 5171 Southwest San Bernardino Valley 1 185 158 649 138 138 167 129 208 92 112 -- -- 5181 Central San Bernardino Mountains 88 105 62 73 67 53 45 47 45 47 49 -- 5197 Central San Bernardino Valley 1 475 127 105 143 133 178 130 122 101 116 108 106 5203 Central San Bernardino Valley 2 235 163 136 139 147 148 136 108 114 134 108 106 5204 East San Bernardino Valley -- -- -- 109 138 172 128 103 97 92 109 102 5817 Southwest San Bernardino Valley 2 -- -- -- -- -- -- -- -- -- -- 124 166 

District Maximum 520 340 649 231 161 219 162 227 116 153 139 219 

 * Less than 12 full months of data.  ** Salton Sea Air Basin *** Refer to 2003 AQMP for 1985 to 1989 data 
TABLE A-11 

Fine Particulate Matter (PM2.5) 

Annual Arithmetic Mean, μg/m3 

STN# LOCATION 1999 2000 2001 2002 2003 2004 LOS ANGELES COUNTY:  060 East San Gabriel Valley 25.6 20.1 21.8 20.8 19.2 18.4  069 East San Fernando Valley 23.3 23.8* 24.9 24.0 20.9 19.2  072 South Coastal Los Angeles County 1 21.5 19.2* 21.4 19.5 18.0 17.6  074 West San Fernando Valley 17.5* 18.1 18.5 18.9 16.4 15.6  077 South Coastal Los Angeles County 2 -- -- -- -- -- 16.6  084 South Central Los Angeles County 24.2 23.0 24.5 23.3 20.2 18.5  085 South San Gabriel Valley 25.7 24.1 26.1 23.9 20.6 19.9  087 Central Los Angeles 23.1 22.0 22.9 21.8 21.3 19.6  088 West San Gabriel Valley 20.6* 19.3 20.9 20.3 18.6 16.6 ORANGE COUNTY: 3176 Central Orange County 24.4 21.0* 22.4* 18.6 17.3 16.8 3812 Saddleback Valley 16.8* 14.7 15.8 15.5 13.1 12.1 RIVERSIDE COUNTY: 4137 Coachella Valley 1** -- 9.6 10.8 10.0 9.0 9.0 4144 Metropolitan Riverside County 1 30.9 28.2* 31.1 27.5 24.9 22.1 4146 Metropolitan Riverside County 2 26.9 25.5 28.3 27.1 22.6 20.8 4157 Coachella Valley 2** 12.6* 11.2 12.2 12.0 11.4 10.7 SAN BERNARDINO COUNTY: 5197 Central San Bernardino Valley 1 25.9 24.5 24.8 24.3 21.8 20.0 5203 Central San Bernardino Valley 2 25.7 25.4* 26.2 25.7 22.2 22.0 5817 Southwest San Bernardino Valley 25.7 24.2 26.2 25.2 23.8 20.9 5818 East San Bernardino Mountains 10.3 10.6 10.9 11.3 10.5 9.5 

District Maximum 30.9 28.2 31.1 27.5 24.9 22.1 

 * Less than 12 full months of data. ** Salton Sea Air Basin 
TABLE A-12 

Fine Particulate Matter (PM2.5) - Percent of Sampling Days 

Exceeding Federal Standard (65 μg/m3) 

STN# LOCATION 1999 2000 2001 2002 2003 2004 LOS ANGELES COUNTY:  060 East San Gabriel Valley 2 1.5 1.3 0.3 1.0 0.4  069 East San Fernando Valley 1 4.3* 3.4 0 1.1 0  072 South Coastal Los Angeles County 1 1 1.3* 0.3 0 0.9 0.3  074 West San Fernando Valley 1* 1.9 0.9 0 0 0  077 South Coastal Los Angeles County 2 -- -- -- -- -- 0  084 South Central Los Angeles County 1 1.7 2.6 0 0 0  085 South San Gabriel Valley 2 3.4 3.2 0 0.9 0  087 Central Los Angeles 2 3.3 1.2 0.3 1.5 0.6  088 West San Gabriel Valley 1* 0.9 0.9 0 0.9 0 ORANGE COUNTY: 3176 Central Orange County 2 2.2* 0.4* 0.3 0.9 0 3812 Saddleback Valley 0* 0.8 0 0 0 0 RIVERSIDE COUNTY: 4137 Coachella Valley 1** -- 0 0 0 0 0 4144 Metropolitan Riverside County 1 6 3.6* 5.8 2.5 2.3 1.5 4146 Metropolitan Riverside County 2 2 4.5 4.7 1.7 0.9 1.8 4157 Coachella Valley 2** 0* 0 0 0 0 0 SAN BERNARDINO COUNTY: 5197 Central San Bernardino Valley 1 3 1.8 3.5 0.9 0.9 1.0 5203 Central San Bernardino Valley 2 4 2.9* 4.5 2.6 0.8 3.8 5817 Southwest San Bernardino Valley 2 1.8 1.8 0 2.5 1.8 5818 East San Bernardino Mountains 0 0 0 0 0 0 

District Maximum 6 4.5 5.8 2.6 2.5 3.8 

* Less than 12 full months of data. ** Salton Sea Air Basin 
TABLE A-13 

Fine Particulate Matter (PM2.5) - Percent of Sampling Days 

Exceeding the New Federal Standard (35 μg/m3)*** 

STN# LOCATION 1999 2000 2001 2002 2003 2004 LOS ANGELES COUNTY:  060 East San Gabriel Valley 17 9 14 12 9 8  069 East San Fernando Valley 18 14* 16 19 14 10  072 South Coastal Los Angeles County 1 9 11* 14 9 7 7  074 West San Fernando Valley 8* 8 7 10 7 4  077 South Coastal Los Angeles County 2 -- -- -- -- 10 5  084 South Central Los Angeles County 18 14 16 18 9 7  085 South San Gabriel Valley 20 13 22 19 9 9  087 Central Los Angeles 15 13 15 13 14 7  088 West San Gabriel Valley 9* 6 8 11 10 6 ORANGE COUNTY: 3176 Central Orange County 17 14* 16* 9 7 6 3812 Saddleback Valley 4* 4 5 3 3 3 RIVERSIDE COUNTY: 4137 Coachella Valley 1** -- 0 1 1 0 0 4144 Metropolitan Riverside County 1 30 26* 33 25 21 15 4146 Metropolitan Riverside County 2 25 22 23 24 19 13 4157 Coachella Valley 2** 0* 0 0 0 0 0 SAN BERNARDINO COUNTY: 5197 Central San Bernardino Valley 1 17 19 15 19 14 14 5203 Central San Bernardino Valley 2 21 21* 23 24 15 15 5817 Southwest San Bernardino Valley 22 14 21 18 17 13 5818 East San Bernardino Mountains -- 0 0 0 0 0 

District Maximum 30 22 33 25 21 15 

* Less than 12 full months of data. ** Salton Sea Air Basin ***Effective December 17, 2006, U.S. EPA has strengthen the standard level from 65 μg/m3 to 35 μg/m3.
TABLE A-14 

Fine Particulate Matter (PM2.5) 

Annual Maximum 24-Hour Average, μg/m3 

STN# LOCATION 1999 2000 2001 2002 2003 2004 LOS ANGELES COUNTY:  060 East San Gabriel Valley 81.3 92.5 79.7 72.4 121.2 75.6  069 East San Fernando Valley 79.5 84.4* 94.7 63.0 120.6 60.1  072 South Coastal Los Angeles County 1 66.9 81.5* 72.9 62.7 115.2 66.6  074 West San Fernando Valley 79.0* 67.5 71.1 48.8 47.5 56.2  077 South Coastal Los Angeles County 2 -- -- -- -- -- 59.7  084 South Central Los Angeles County 67.8 82.1 73.1 64.0 54.8 55.8  085 South San Gabriel Valley 85.6 89.5 77.3 61.0 90.3 60.7  087 Central Los Angeles 69.3 87.8 73.4 66.3 83.7 75.0  088 West San Gabriel Valley 73.0* 66.3 78.1 57.8 89.0 59.4 ORANGE COUNTY: 3176 Central Orange County 68.7 113.9* 70.8* 68.6 115.5 58.9 3812 Saddleback Valley 56.6* 94.7 53.4 58.5 50.6 49.4 RIVERSIDE COUNTY: 4137 Coachella Valley 1** -- 28.5 44.7 42.3 21.2 27.1 4144 Metropolitan Riverside County 1 111.2 119.6* 98.0 77.6 104.3 91.7 4146 Metropolitan Riverside County 2 90.0 79.3 74.9 75.5 73.3 93.8 4157 Coachella Valley 2** 29.6* 28.6 33.5 26.8 26.8 28.5 SAN BERNARDINO COUNTY: 5197 Central San Bernardino Valley 1 98.0 72.9 74.8 66.6 98.1 71.4 5203 Central San Bernardino Valley 2 121.5 89.8* 78.5 82.1 73.9 93.4 5817 Southwest San Bernardino Valley 85.8 73.4 71.2 64.8 88.9 86.1 5818 East San Bernardino Mountains 32.1 29.0 34.6 34.1 35.0 28.6 

District Maximum 121.5 119.6 98.0 82.1 121.2 93.8 

* Less than 12 full months of data. ** Salton Sea Air Basin 
TABLE A-15 

Fine Particulate Matter (PM2.5) 

24-Hour Average 98th Percentile Concentration, μg/m3 

STN# LOCATION 1999 2000 2001 2002 2003 2004 LOS ANGELES COUNTY:  060 East San Gabriel Valley 64 62 61 51 56 54  069 East San Fernando Valley 50 83 69 55 60 49  072 South Coastal Los Angeles County 1 51 64 49 47 47 46  074 West San Fernando Valley 40 50 57 45 45 53  077 South Coastal Los Angeles County 2 -- -- -- -- -- 42  084 South Central Los Angeles County 53 63 66 53 52 53  085 South San Gabriel Valley 60 71 67 58 50 52  087 Central Los Angeles 52 73 58 55 61 50  088 West San Gabriel Valley 60 54 55 49 48 47 ORANGE COUNTY: 3176 Central Orange County 66 66 59 48 52 48 3812 Saddleback Valley 45 37 46 46 38 39 RIVERSIDE COUNTY: 4137 Coachella Valley 1** -- 23 33 23 20 23 4144 Metropolitan Riverside County 1 79 77 74 66 77 60 4146 Metropolitan Riverside County 2 62 67 66 64 56 54 4157 Coachella Valley 2** 30 26 30 22 25 27 SAN BERNARDINO COUNTY: 5197 Central San Bernardino Valley 1 66 65 70 57 54 63 5203 Central San Bernardino Valley 2 72 70 68 66 58 72 5817 Southwest San Bernardino Valley 86 65 65 57 67 60 5818 East San Bernardino Mountains 31 27 30 32 29 23 

District Maximum 86 83 74 66 77 72 

* Less than 12 full months of data. ** Salton Sea Air Basin 
TABLE A-16 

Carbon Monoxide - Number of Days Maximum 8-Hour Average*** 

Exceeded the Federal Standard (≥ 9.5 ppm) 

STN# LOCATION 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 LOS ANGELES COUNTY:  060 East San Gabriel Valley 1 0 0 0 0 0 0 0 0 0 0 0 0  069 East San Fernando Valley 10 8 3 0 5 4 0* 0 0 0 0 0  072 South Coastal Los Angeles County 0 0 0 0* 0 0 0* 0 0 0 0 0  074 West San Fernando Valley 12 9 1 0 4 2 0 1 0 0 1 0  075 Pomona/Walnut Valley 0 0 0 0 0 0 0 0 0 0 0 0  084 South Central Los Angeles County 1 42 37 31 22 22 13 20 14 10 8 2 0  085 South San Gabriel Valley 0 0 0 0 0 0 0 0 0 0 0 0  087 Central Los Angeles 2 0 2 0 0 0 0 0 0 0 0 0  088 West San Gabriel Valley 2 1 0 0 0 0 0 0 0 0 0 0  090 Santa Clarita Valley 0 0 0 0 0 0 0 0 0 0 0 0  091 Northwest Coastal Los Angeles County 0 0 0 0 0 0 0 0 0 0 0 0  094 Southwest Coastal Los Angeles County 1 10 7 7 3 5 0 5 1 0 0 0 0  820 Southwest Coastal Los Angeles County 2 -- -- -- -- -- -- -- -- -- -- -- --  591 East San Gabriel Valley 2 -- -- -- -- -- -- -- -- -- -- 0 0 ORANGE COUNTY: 3176 Central Orange County 2 0 0 0 0 0 0 0 0 0* 0 0* 3177 North Orange County 1 0 0 0 0 0 0 0 0 0 0 0 3186 Saddleback Valley 1 0 0 0 0 0 0 0 0 0 0 0* -- 3195 North Coastal Orange County 4 0 0 0 0 0 0 0 0 0 0* 0 3812 Saddleback Valley 2 -- -- -- -- -- -- -- -- -- -- 0* 0 RIVERSIDE COUNTY: 4137 Coachella Valley 1** 0 0 0* 0 0 0 0 0 0 0 0 0 4144 Metropolitan Riverside County 1 0 0 0 0 0 0 0 0* 0 0 0 0 4146 Metropolitan Riverside County 2 0 0 0 0 0 0 0 0 0 0* 0 0 4150 San Gorgonio Pass -- -- -- -- -- -- -- -- -- -- -- -- 4155 Norco/Corona -- -- -- -- -- -- -- -- -- -- -- -- 4158 Lake Elsinore -- -- -- -- -- -- -- -- -- -- 0 0 SAN BERNARDINO COUNTY: 5175 Northwest San Bernardino Valley 0 0* -- -- -- -- -- -- -- -- 0 0 5181 Central San Bernardino Mountains -- -- -- -- -- -- -- -- -- -- -- -- 5197 Central San Bernardino Valley 1 0 0* -- -- -- -- -- -- -- -- -- -- 5203 Central San Bernardino Valley 2 0 0 0 0 0 0 0 0* 0 0 0* 0 5204 East San Bernardino Valley 1 -- -- -- -- -- -- -- -- -- -- -- -- 

 * Less than 12 full months of data.  ** Salton Sea Air Basin *** Refer to 2003 AQMP for 1976 to 1989 data 
TABLE A-17 

Carbon Monoxide - Number of Days Maximum 8-Hour Average*** 

Exceeded the Federal Alert Level (> 15 ppm) 

STN# LOCATION 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 LOS ANGELES COUNTY:  060 East San Gabriel Valley 1 0 0 0 0 0 0 0 0 0 0 0 0  069 East San Fernando Valley 0 0 0 0 0 0 0* 0 0 0 0 0  072 South Coastal Los Angeles County 0 0 0 0* 0 0 0* 0 0 0 0 0  074 West San Fernando Valley 0 0 0 0 0 0 0 0 0 0 0 0  075 Pomona/Walnut Valley 0 0 0 0 0 0 0 0 0 0 0 0  084 South Central Los Angeles County 1 4 3 3 0 0 0 1 1 0 0 0 0  085 South San Gabriel Valley 0 0 0 0 0 0 0 0 0 0 0 0  087 Central Los Angeles 0 0 0 0 0 0 0 0 0 0 0 0  088 West San Gabriel Valley 0 0 0 0 0 0 0 0 0 0 0 0  090 Santa Clarita Valley 0 0 0 0 0 0 0 0 0 0 0 0  091 Northwest Coastal Los Angeles County 0 0 0 0 0 0 0 0 0 0 0 0  094 Southwest Coastal Los Angeles County 1 0 0 0 0 0 0 0 0 0 0 0 0  820 Southwest Coastal Los Angeles County 2 -- -- -- -- -- -- -- -- -- -- -- --  591 East San Gabriel Valley 2 -- -- -- -- -- -- -- -- -- -- 0 0 

ORANGE COUNTY: 

3176 Central Orange County 0 0 0 0 0 0 0 0 0 0* 0 0* 3177 North Orange County 0 0 0 0 0 0 0 0 0 0 0 0 3186 Saddleback Valley 1 0 0 0 0 0 0 0 0 0 0 0* -- 3195 North Coastal Orange County 0 0 0 0 0 0 0 0 0 0 0* 0 3812 Saddleback Valley 2 -- -- -- -- -- -- -- -- -- -- 0* 0 RIVERSIDE COUNTY: 4137 Coachella Valley 1** 0 0 0* 0* 0 0 0 0 0 0 0 0 4144 Metropolitan Riverside County 1 0 0 0 0 0 0 0 0* 0 0 0 0 4146 Metropolitan Riverside County 2 0 0 0 0 0 0 0 0 0 0* 0 0 4150 San Gorgonio Pass -- -- -- -- -- -- -- -- -- -- -- -- 4155 Norco/Corona -- -- -- -- -- -- -- -- -- -- -- -- 4158 Lake Elsinore -- -- -- -- -- -- -- -- -- -- 0 0 SAN BERNARDINO COUNTY: 5175 Northwest San Bernardino Valley 0 0* -- -- -- -- -- -- -- -- -- -- 5181 Central San Bernardino Mountains -- -- -- -- -- -- -- -- -- -- -- -- 5197 Central San Bernardino Valley 1 0 0* -- -- -- -- -- -- -- -- -- -- 5203 Central San Bernardino Valley 2 0 0 0 0 0 0 0 0* 0 0 0* 0 5204 East San Bernardino Valley 1 -- -- -- -- -- -- -- -- -- -- -- -- 

District Maximum 4 3 3 0 0 0 1 1 0 0 0 0 

 * Less than 12 full months of data.  ** Salton Sea Air Basin *** Refer to 2003 AQMP for 1976 to 1989 data 
TABLE A-18 

Carbon Monoxide 

Annual Maximum 8-Hour Average, ppm*** 

STN# LOCATION 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 LOS ANGELES COUNTY:  060 East San Gabriel Valley 1 5.1 5.9 4.9 4.0 4.5 6.3 4.0 4.3 3.9 3.9 4.9 2.9  069 East San Fernando Valley 13.0 10.6 10.5 8.4 10.7 12.0 9.3 7.4 7.5 9.0 6.1 4.9 

 072 South Coastal Los Angeles County 9.1 9.3 8.1 6.9 8.9 6.6 6.9 6.7 6.6 5.4 5.8 4.7  074 West San Fernando Valley 14.9 13.5 9.9 9.0 10.8 10.3 8.5 9.8 9.3 7.6 9.8 6.0 

 075 Pomona/Walnut Valley 7.5 7.1 8.3 5.5 6.8 6.1 5.0 5.0 7.3 6.7 4.9 3.4  084 South Central Los Angeles County 1 16.8 17.4 18.75 14.63 18.10 13.86 17.3 17.0 13.4 11.0 10.0 7.7 

 085 South San Gabriel Valley 9.4 9.1 8.62 6.43 9.29 7.86 8.1 6.2 6.1 5.6 5.3 4.0 

 087 Central Los Angeles 9.9 9.0 9.50 6.75 8.43 8.37 8.4 7.9 6.1 6.3 6.0 4.6  088 West San Gabriel Valley 10.0 9.5 7.25 6.25 8.50 9.12 7.1 6.0 6.3 6.6 7.4 5.0 

 090 Santa Clarita Valley 4.6 5.1 3.71 3.86 3.86 4.12 3.9 6.8 3.4 3.6 4.9 3.1  091 Northwest Coastal Los Angeles County 8.0 6.1 5.87 5.43 6.00 5.62 4.5 4.4 4.5 3.8 4.3 3.0 

 094 Southwest Coastal Los Angeles County 1 12.7 11.3 12.29 10.71 12.00 8.86 11.6 10.3 9.4 8.4 7.0 5.1 

 820 Southwest Coastal Los Angeles County 2 -- -- -- -- -- -- -- -- -- -- -- --  591 East San Gabriel Valley 2 -- -- -- -- -- -- -- -- -- -- 3.1 2.5-- ORANGE COUNTY: 

3176 Central Orange County 11.7 8.6 9.37 7.71 8.62 8.00 7.5 5.8 5.3 5.3 6.8 4.7 3177 North Orange County 9.6 8.0 9.14 6.00 8.75 6.62 6.9 6.0 6.1 5.3 6.1 4.7 

3186 Saddleback Valley 1 5.6 4.8 7.25 4.13 5.37 4.00 4.0 3.6 3.1 2.5 2.3 -- 3195 North Coastal Orange County 10.7 8.1 9.14 7.33 7.86 6.57 7.3 5.8 7.0 6.4 6.3 4.6 

3812 Saddleback Valley 2 -- -- -- -- -- -- -- -- -- -- 3.3 2.4 RIVERSIDE COUNTY: 

4137 Coachella Valley 1** 2.3 2.5 2.4 2.00 1.87 1.50 1.6 1.4 1.6 1.8 1.6 1.5 4144 Metropolitan Riverside County 1 6.3 7.4 5.25 7.13 5.75 5.71 5.0 5.8 4.6 4.4 4.3 3.4 

4146 Metropolitan Riverside County 2 7.3 6.9 6.12 6.25 7.25 6.50 5.4 5.0 4.6 4.1 4.3 4.5 4149 Perris Valley -- -- -- -- -- -- -- -- -- -- -- -- 4155 Norco/Corona -- -- -- -- -- -- -- -- -- -- -- -- 

4157 Coachella Valley 2** -- -- -- -- -- -- -- -- -- -- 2.1 -- 

4158 Lake Elsinore -- -- -- -- -- -- -- -- -- -- 2.0 2.0 SAN BERNARDINO COUNTY: 

5175 Northwest San Bernardino Valley 6.6 4.6 -- -- -- -- -- -- -- -- 2.6 1.8 5181 Central San Bernardino Mountains -- -- -- -- -- -- -- -- -- -- -- -- 5197 Central San Bernardino Valley 1 4.9 4.4 -- -- -- -- -- -- -- -- -- -- 5203 Central San Bernardino Valley 2 6.0 7.0 5.9 6.0 6.5 6.3 4.6 6.0 4.6 4.0 4.3 3.3 5204 East San Bernardino Valley 1 -- -- -- -- -- -- -- -- -- -- -- -- 

District Maximum 16.8 17.4 18.8 14.6 18.1 13.9 17.3 17.0 13.5 11.7 10.0 7.7 

 * Less than 12 full months of data. ** Salton Sea Air Basin *** Refer to 2003 AQMP for 1976 to 1989 data 
TABLE A-19 

Nitrogen Dioxide - Annual Average of All Hours, pphm***

(To Be Compared to Federal Standard of 5.34 pphm, Annual Average of All Hours) 

STN# LOCATION 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 LOS ANGELES COUNTY:  060 East San Gabriel Valley 1 4.10 4.50 4.03 4.00 4.30 4.64 4.15 3.38 3.64 3.90 3.66 3.31  069 East San Fernando Valley 4.79 4.68 5.01 4.40 4.97 4.54 4.61 4.24 4.16 4.56 4.15 4.19 

 072 South Coastal Los Angeles County 3.93 4.11 3.89 3.57 3.46 3.67 3.42 3.33 3.39 3.42 3.13 3.08  074 West San Fernando Valley 3.40 3.99 3.17 3.06 3.39 3.17 3.07 2.60 2.66 2.87 2.85 2.66  075 Pomona/Walnut Valley 1 5.55 5.50 5.07 4.99 4.80 4.56 4.26 4.33 4.33 5.03 4.35 3.71 

 084 South Central Los Angeles County 1 4.08 4.37 4.55 4.09 4.99 4.63 4.12 4.28 3.93 4.28 3.86 3.69 

 085 South San Gabriel Valley 4.99 4.69 4.43 4.28 4.49 4.56 3.93 3.63 3.69 3.91 3.66 3.52 

 087 Central Los Angeles 4.67 4.93 4.04 3.32 4.76 4.50 4.36 4.30 3.98 3.91 4.04 3.78 

 088 West San Gabriel Valley 4.74 5.02 4.23 3.90 4.28 3.75 3.78 3.41 3.51 3.79 2.96 3.45  090 Santa Clarita Valley 3.16 3.24 2.76 2.89 3.27 3.05 -- -- -- 2.84 2.46 2.39  091 Northwest Coastal Los Angeles County 3.24 2.78 2.84 2.87 2.96 2.78 2.89 2.85 2.71 2.91 2.73 2.51 

 094 Southwest Coastal Los Angeles County 1 3.39 2.98 3.20 3.00 3.22 3.05 2.85 2.80 2.95 2.95 2.75 2.50 

 820 Southwest Coastal Los Angeles County 2 -- -- -- -- -- -- -- -- -- -- -- -- 

 591 East San Gabriel Valley 2 3.77 4.30 3.53 3.39 3.62 3.80 3.28 3.00 2.76 3.28 2.90 2.74 ORANGE COUNTY: 

3176 Central Orange County 4.69 4.48 3.94 3.54 3.80 3.71 3.19 3.32 3.36 3.27 3.00 2.93* 3177 North Orange County 4.47 4.26 3.79 3.87 4.14 3.91 3.54 3.29 3.44 3.51 3.04 2.75 

3195 North Coastal Orange County 2.72 2.60 2.49 2.20 2.44 2.39 2.06 1.99 2.00 2.09 2.05 1.82 RIVERSIDE COUNTY: 

4137 Coachella Valley 1** 2.06 2.08 2.10 1.95 2.19 2.23 2.10 1.58 1.70 1.95 1.78 1.75 4144 Metropolitan Riverside County 3.36 3.51 3.04 2.98 3.20 3.06 2.94 2.62 2.25 2.25 2.36 2.47 

4149 Perris Valley 2.82 -- -- -- -- -- -- -- -- -- -- -- 

4157 Coachella Valley 2** -- -- -- -- -- -- -- -- -- -- 0.99 -- 4158 Lake Elsinore -- -- -- -- 2.12 2.08 1.82 1.65 1.74 2.00 1.75 1.85 4164 Banning Airport -- -- -- -- -- -- -- -- 2.15 2.43 2.37 2.11 SAN BERNARDINO COUNTY: 5175 Northwest San Bernardino Valley 4.11 4.28 3.96 4.21 4.15 4.64 3.87 3.41 3.59 3.98 3.80 3.84 5197 Central San Bernardino Valley 1 3.43 3.77 3.44 3.72 4.03 4.24 3.86 3.65 3.62 3.88 3.64 3.58 

5203 Central San Bernardino Valley 2 3.93 3.55 3.56 3.76 4.11 4.04 3.84 3.53 3.39 3.58 3.25 3.03 

District Maximum 5.55 5.50 5.07 4.99 4.99 4.64 4.61 4.33 4.33 5.03 4.35 4.19 

 * Less than 12 full months of data.  ** Salton Sea Air Basin *** Refer to 2003 AQMP for 1976 to 1989 data 
TABLE A-20 

Nitrogen Dioxide - Number of Days 1-Hour Average 

Exceeded the State Standard (> .25 ppm)*** 

STN# LOCATION 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 LOS ANGELES COUNTY:  060 East San Gabriel Valley 1 0 0 0 0 0 0 0 0 0 0 0 0  069 East San Fernando Valley 0 2 0 0 0 0 0 0 0 0 0 0  072 South Coastal Los Angeles County 1 2 0 0 0 0 0 0 0 0 0 0  074 West San Fernando Valley 0 0 0 0 0 0 0 0 0 0 0 0  075 Pomona/Walnut Valley 1 0 0 0 0 0 0 0 0 0 0 0 0  084 South Central Los Angeles County 1 1 2 0 0 0 0 0 0 0 0 0 0  085 South San Gabriel Valley 2 0 1 1 0 0 0 0 0 0 0 0  087 Central Los Angeles 3 5 1 0 0 0 0 0 0 0 0 0  088 West San Gabriel Valley 0 2 0 0 0 0 0 0 0 0 0 0  090 Santa Clarita Valley 0 0 0 0 0 0 -- -- -- 0 0 0  091 Northwest Coastal Los Angeles County 0 0 0 0 0 0 0 0 0 0 0 0  094 Southwest Coastal Los Angeles County 1 0 0 0 0 0 0 0 0 0 0 0 0  820 Southwest Coastal Los Angeles County 2 -- -- -- -- -- -- -- -- -- -- -- -- 

 591 East San Gabriel Valley 2 0 0 0 0 0 0 0 0 0 0 0 0 ORANGE COUNTY: 

3176 Central Orange County 0 0 0 0 0 0 0 0 0 0 0 0 3177 North Orange County 0 0 0 0 0 0 0 0 0 0 0 0 3195 North Coastal Orange County 0 0 0 0 0 0 0 0 0 0 0 0 3812 Saddleback Valley RIVERSIDE COUNTY: 4137 Coachella Valley 1** 0 0 0 0 0 0 0 0 0 0 0 0 4144 Metropolitan Riverside County 0 0 0 0 0 0 0 0 0 0 0 0 4149 Perris Valley 0 -- -- -- -- -- -- -- -- -- -- -- 4157 Coachella Valley 2** -- -- -- -- -- -- -- -- -- -- 0 -- 4158 Lake Elsinore -- -- -- -- 0 0 0 0 0 0 0 0 4164 Banning Airport -- -- -- -- -- -- -- -- 1 1 0 0 SAN BERNARDINO COUNTY: 5175 Northwest San Bernardino Valley 0 0 0 0 0 0 0 0 0 0 0 0 5197 Central San Bernardino Valley 1 0 0 0 0 0 0 0 0 0 0 0 0 5203 Central San Bernardino Valley 2 0 0 0 0 0 0 0 0 0 0 0 0 

 * Less than 12 full months of data.  ** Salton Sea Air Basin *** Refer to 2003 AQMP for 1976 to 1989 data 
TABLE A-21 

Nitrogen Dioxide 

Annual Maximum 1-Hour, ppm*** 

STN# LOCATION 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 20LOS ANGELES COUNTY:  060 East San Gabriel Valley 1 0.21 0.25 0.15 0.17 0.19 0.22 0.15 0.16 0.14 0.16 0.15 0.1 069 East San Fernando Valley 0.23 0.29 0.19 0.17 0.18 0.18 0.2 0.2 0.14 0.18 0.17 0.2

 072 South Coastal Los Angeles County 0.27 0.28 0.18 0.2 0.2 0.21 0.17 0.2 0.16 0.15 0.14 0.1

 074 West San Fernando Valley 0.19 0.17 0.17 0.15 0.17 0.14 0.16 0.2 0.14 0.12 0.11 0.0

 075 Pomona/Walnut Valley 1 0.21 0.22 0.18 0.2 0.17 0.18 0.18 0.15 0.15 0.16 0.14 0.1

 084 South Central Los Angeles County 1 0.26 0.26 0.25 0.23 0.2 0.21 0.25 0.2 0.16 0.18 0.14 0.1

 085 South San Gabriel Valley 0.27 0.25 0.27 0.26 0.24 0.23 0.17 0.15 0.14 0.16 0.14 0.1

 087 Central Los Angeles 0.28 0.38 0.3 0.21 0.22 0.24 0.25 0.2 0.17 0.21 0.16 0.1

 088 West San Gabriel Valley 0.23 0.32 0.22 0.18 0.18 0.22 0.19 0.17 0.16 0.16 0.17 0.1

 090 Santa Clarita Valley 0.15 0.17 0.11 0.13 0.12 0.16 -- -- -- 0.10 0.10 0.1 091 Northwest Coastal Los Angeles County 0.2 0.25 0.17 0.17 0.16 0.2 0.18 0.14 0.13 0.13 0.16 0.1

 094 Southwest Coastal Los Angeles County 1 0.23 0.21 0.19 0.16 0.22 0.18 0.15 0.17 0.15 0.13 0.13 0.1

 820 Southwest Coastal Los Angeles County 2 -- -- -- -- -- -- -- -- -- -- -- -

 591 East San Gabriel Valley 2 0.19 0.23 0.16 0.16 0.19 0.2 0.14 0.13 0.13 0.14 0.13 0.1

ORANGE COUNTY: 

3176 Central Orange County 0.21 0.2 0.21 0.2 0.19 0.18 0.15 0.1 0.13 0.12 0.13 0.13177 North Orange County 0.22 0.2 0.17 0.18 0.23 0.2 .16. 0.15 0.13 0.16 0.12 0.1

3195 North Coastal Orange County 0.22 0.16 0.15 0.14 0.16 0.18 0.14 0.12 0.12 0.12 0.11 0.0

RIVERSIDE COUNTY: 

4137 Coachella Valley 1** 0.09 0.09 0.09 0.15 0.08 0.09 0.08 0.07 0.07 0.07 0.07 0.04144 Metropolitan Riverside County 0.16 0.16 0.23 0.14 0.18 0.15 0.11 0.12 0.1 0.13 0.1 0.1

4149 Perris Valley 0.11 -- -- -- -- -- -- -- -- -- -- -4157 Coachella Valley 2** -- -- -- -- -- -- -- -- -- -- 0.06 -4158 Lake Elsinore -- -- -- -- 0.11 0.21 0.1 0.11 0.09 0.11 0.08 0.04164 Banning Airport -- -- -- -- -- -- -- -- 0.26 0.31 0.21 0.2

SAN BERNARDINO COUNTY: 

5175 Northwest San Bernardino Valley 0.19 0.21 0.14 0.16 0.17 0.2 0.15 0.15 0.14 0.13 0.15 0.15197 Central San Bernardino Valley 1 0.2 0.19 0.14 0.16 0.18 0.17 0.17 0.14 0.15 0.15 0.12 0.1

5203 Central San Bernardino Valley 2 0.2 0.16 0.13 0.15 0.16 0.16 0.15 0.14 0.11 0.14 0.1 0.1

District Maximum 0.28 0.38 0.3 0.26 0.22 0.24 0.25 0.2 0.26 0.31 0.21 0.2

 * Less than 12 full months of data. ** Salton Sea Air Basin *** Refer to 2003 AQMP for 1976 to 1989 data 
TABLE A-22 

Sulfur Dioxide - Annual Average, pphm*** 

STN# LOCATION 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 LOS ANGELES COUNTY:  060 East San Gabriel Valley 1 0.11 -- -- -- -- -- -- -- -- -- -- --  069 East San Fernando Valley 0.18 0.09 0.10 0.12 0.07 0.01 0.04 0.03 0.02 0.01 0.01 0.07 

 072 South Coastal Los Angeles County 0.31 0.43 0.37 0.36 0.31 0.23 0.25 0.24 0.18 0.27 0.15 0.22  074 West San Fernando Valley 0.15 -- -- -- -- -- -- -- -- -- -- --  084 South Central Los Angeles County 1 0.33 0.30 0.31 0.23 0.26 0.30 -- -- -- -- -- --  085 South San Gabriel Valley 0.43 -- -- -- -- -- -- -- -- -- -- --  087 Central Los Angeles 0.17 0.17 0.15 0.03 0.07 0.10 0.15 0.07 0.08 0.23 0.09 0.28 

 088 West San Gabriel Valley 0.15 -- -- -- -- -- -- -- -- -- -- --  090 Santa Clarita Valley 0.09 -- -- -- -- -- -- -- -- -- -- --  091 Northwest Coastal Los Angeles County 0.21 -- -- -- -- -- -- -- -- -- -- --  094 Southwest Coastal Los Angeles County 1 0.35 0.40 0.57 0.31 0.22 0.27 0.25 0.14 0.39 0.40 0.17 0.41  820 Southwest Coastal Los Angeles County 2 -- -- -- -- -- -- -- -- -- -- -- -- ORANGE COUNTY: 3176 Central Orange County 1 0.18 -- -- -- -- -- -- -- -- -- -- -- 3177 North Orange County 0.11 0.12 0.06 0.06 0.09 0.09 -- -- -- -- -- -- 3190 Central Orange County 2 0.19 0.11 0.11 0.08 -- -- -- -- -- -- -- -- 3195 North Coastal Orange County 0.07 0.07 0.06 0.05 0.07 0.07 0.01 0.03 0.04 0.07 0.05 0.15 

RIVERSIDE COUNTY: 

4144 Metropolitan Riverside County 0.03 0.02 0.02 0.03 0.02 0.01 0.01 0.03 0.11 0.14 0.08 0.09 SAN BERNARDINO COUNTY: 5175 Northwest San Bernardino Valley 0.12 -- -- -- -- -- -- -- -- -- -- -- 5197 Central San Bernardino Valley 1 0.01 0.05 0.12 0.00 0.02 0.06 0.01 0.00 0.07 0.18 0.18 0.21 

5203 Central San Bernardino Valley 2 0.01 -- -- -- -- -- -- -- -- -- -- -- 

District Maximum 0.43 0.43 0.57 0.36 0.31 0.30 0.25 0.24 0.39 0.40 0.18 0.41 

 * Less than 12 full months of data.  ** Salton Sea Air Basin *** Refer to 2003 AQMP for 1976 to 1989 data 
TABLE A-23 

Sulfur Dioxide 

Annual Maximum 1-Hour Average, ppm*** 

STN# LOCATION 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 LOS ANGELES COUNTY:  60 East San Gabriel Valley 0.03 -- -- -- -- -- -- -- -- -- -- --  69 East San Fernando Valley 0.02 0.01 0.03 0.02 0.03 0.01 0.01 0.04 0.01 0.01 0.01 0.01 

 72 South Coastal Los Angeles County 0.05 0.14 0.11 0.05 0.04 0.14 0.04 0.04 0.08 0.05 0.05 0.05  74 West San Fernando Valley 0.02 - -- -- -- -- -- -- -- -- -- --  84 South Central Los Angeles County 0.04 0.05 0.06 0.03 0.02 0.03 -- -- -- -- -- --  85 South San Gabriel Valley 0.04 -- -- -- -- -- -- -- -- -- -- --  87 Central Los Angeles 0.02 0.02 0.05 0.01 0.02 0.01 0.01 0.02 0.14 0.05 0.08 0.03 

 88 West San Gabriel Valley 0.02 -- -- -- -- -- -- -- -- -- -- --  90 Santa Clarita Valley 0.01 -- -- -- -- -- -- -- -- -- -- --  91 Northwest Coastal Los Angeles County 0.02 -- -- -- -- -- -- -- -- -- -- --  94 Southwest Coastal Los Angeles County 1 0.31 0.12 0.15 0.07 0.04 0.06 0.06 0.1 0.03 0.09 0.17 0.04  820 Southwest Coastal Los Angeles County 2 -- -- -- -- -- -- -- -- -- -- -- -- ORANGE COUNTY: 3176 Central Orange County 1 0.02 -- -- -- -- -- -- -- -- -- -- -- 3177 North Orange County 0.03 0.04 0.02 0.02 0.02 0.02 -- -- -- -- -- -- 3190 Central Orange County 2 0.03 0.03 0.1 0.02 -- -- -- -- -- -- -- -- 3195 North Coastal Orange County 0.02 0.04 0.02 0.01 0.02 0.02 0.01 0.03 0.02 0.02 0.02 0.01 

RIVERSIDE COUNTY: 

4144 Metropolitan Riverside County 0.03 0.02 0.02 0.02 0.02 0.01 0.01 0.04 0.03 0.03 0.11 0.02 SAN BERNARDINO COUNTY: 5175 Northwest San Bernardino Valley 0.01 -- -- -- -- -- -- -- -- -- -- -- 5197 Central San Bernardino Valley 1 0.01 0.05 0.02 0.01 0.03 0.02 0.01 0.01 0.02 0.01 0.02 0.01 

5203 Central San Bernardino Valley 2 0.01 -- -- -- -- -- -- -- -- -- -- -- 

District Maximum 0.31 0.14 0.15 0.07 0.04 0.14 0.06 0.1 0.14 0.09 0.17 0.05 

 * Less than 12 full months of data.  ** Salton Sea Air Basin *** Refer to 2003 AQMP for 1976 to 1989 data 
TABLE A-24 

Sulfate - Percent of Sampling Days Exceeding the State Standard*** 

(≥ 25 μg/m3, 24-hour Average) 

STN# LOCATION 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 LOS ANGELES COUNTY:  60 East San Gabriel Valley 0 0 0 0 0 0 0 0 0 0 0 0  69 East San Fernando Valley 2 0 0 0 0 0 -- -- -- -- -- --  72 South Coastal Los Angeles County 0 0 0 0 0 0 0 0 0 0 2 0  84 South Central Los Angeles County 2 0 0 0 0 0 0 0 0 0 0 0  85 South San Gabriel Valley 0 0 0 0 2 0 0 0 0 2 0 0  87 Central Los Angeles 2 0 0 0 0 0 0 0 0 0 0 0  88 West San Gabriel Valley 2 0 0 0 0 0 0 0 0 0 0 0  91 Northwest Coastal Los Angeles County 0 0 0 0 2 0 0 0 0 0 0 0  94 Southwest Coastal Los Angeles County 0 0 0 0 2 0 0 0 0 0 0 0 ORANGE COUNTY: 3176 Central Orange County 1 0 0 0 0 0 0 -- -- -- -- -- -- 3186 Saddleback Valley 0 -- -- -- -- -- -- -- -- -- -- -- 3190 Central Orange County 2 0 0 0 0 -- -- -- -- -- -- -- -- RIVERSIDE COUNTY: 4137 Coachella Valley 1** 0 -- -- -- -- -- -- -- -- -- -- -- 4144 Metropolitan Riverside County 1 0 0 0 0 0 2 0 0 0 0 0 0 4146 Metropolitan Riverside County 2 0 0 0 0 0 0 0 0 0 0 0 0 4149 Perris Valley 0 -- -- -- -- -- -- -- -- -- -- -- 4150 San Gorgonio Pass 0 -- -- -- -- -- -- -- -- -- -- -- 4157 Coachella Valley 2** 0 -- -- -- -- -- -- -- -- -- -- -- SAN BERNARDINO COUNTY: 5171 Southwest San Bernardino Valley 0 -- -- -- -- -- -- -- -- -- -- -- 5175 Northwest San Bernardino Valley 0 0 0 0 0 0 0 0 0 0 0 0 5181 Central San Bernardino Mountains 0 -- -- -- -- -- -- -- -- -- -- -- 5197 Central San Bernardino Valley 1 0 0 0 0 0 0 0 0 0 0 0 0 5203 Central San Bernardino Valley 2 0 0 0 0 0 0 0 0 0 0 0 0 

 * Less than 12 full months of data.  ** Salton Sea Air Basin *** Refer to 2003 AQMP for 1976 to 1989 data 
TABLE A-25 

Sulfate - Maximum 24-Hour Averages*** 

(To Be Compared to State Standard of 25 μg/m3, 24-Hour Average) 

STN# LOCATION 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 LOS ANGELES COUNTY:  60 East San Gabriel Valley 16.0 19.2 16.8 19.1 17.5 12.9 17.1 12.7 10.2 17.8 17.2 14.1  69 East San Fernando Valley 25.9 18.6 12.9 20.1 18.3 13.7 -- -- -- -- -- --  72 South Coastal Los Angeles County 22.6 19.9 22.6 15.6 17.1 16.9 19.9 11.4 14.5 13.7 26.7 15.9 

 84 South Central Los Angeles County 28.1 22.4 18.7 13.7 23.1 18.8 16.0 11.4 12.0 15.6 11.4 15.4  85 South San Gabriel Valley 21.1 21.6 17.0 15.5 26.2 16.3 13.7 13.1 12.0 25.6 13.1 14.5 

 87 Central Los Angeles 25.3 23.1 19.4 17.6 21.7 15.5 12.8 14.3 10.6 17.9 16.4 15.9 

 88 West San Gabriel Valley 28.4 20.1 11.5 18.8 14.5 13.2 12.0 11.6 9.2 16.4 13.9 13.4 

 91 Northwest Coastal Los Angeles County 24.8 20.9 12.3 18.1 26.8 13.3 12.2 14.0 11.2 13.9 14.1 15.6  94 Southwest Coastal Los Angeles County 24.8 24.7 17.6 20.5 26.7 20.4 18.4 14.4 13.5 18.8 16.2 20.6 

ORANGE COUNTY: 

3176 Central Orange County 1 18.3 20.6 16.0 15.3 14.5 12.8 -- -- -- -- -- -- 3186 Saddleback Valley 13.4 -- -- -- -- -- -- -- -- -- -- -- 3190 Central Orange County 2 16.8 16.9 16.0 14.7 -- -- -- -- -- -- -- -- RIVERSIDE COUNTY: 4137 Coachella Valley 1** 5.6 -- -- -- -- -- -- -- -- -- -- -- 4144 Metropolitan Riverside County 1 19.9 14.8 12.3 13.7 20.4 26.3 14.9 13.1 10.1 10.7 11.0 10.7 4146 Metropolitan Riverside County 2 19.3 12.8 12.1 15.1 15.7 22.9 17.0 10.4 12.8 10.6 10.2 9.2 4149 Perris Valley 12.9 -- -- -- -- -- -- -- -- -- -- -- 4150 San Gorgonio Pass 8.6 -- -- -- -- -- -- -- -- -- -- -- 4157 Coachella Valley 2** 7.0 -- -- -- -- -- -- -- -- -- -- -- SAN BERNARDINO COUNTY: 5171 Southwest San Bernardino Valley 19.9 -- -- -- -- -- -- -- -- -- -- -- 5175 Northwest San Bernardino Valley 18.7 19.0 13.2 17.1 15.8 12.5 13.6 9.7 10.5 11.7 11.5 10.7 

5181 Central San Bernardino Mountains 6.6 -- -- -- -- -- -- -- -- -- -- -- 5197 Central San Bernardino Valley 1 18.3 20.2 13.4 16.7 15.5 13.4 13.6 10.2 10.1 12.4 10.7 10.7 

5203 Central San Bernardino Valley 2 17.3 18.3 12.9 17.2 14.9 12.5 11.2 9.1 11.5 10.9 12.4 12.4 

District Maximum 28.4 24.7 22.6 20.5 26.8 26.3 19.9 14.4 14.5 25.6 26.7 20.6 

 * Less than 12 full months of data.  ** Salton Sea Air Basin *** Refer to 2003 AQMP for 1976 to 1989 data 
TABLE A-26 

Lead - Highest Calendar Quarter Mean, μg/m3***

(To Be Compared to Federal Standard of 1.5 μg/m3, Calendar Quarter Average) 

STN# LOCATION 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 LOS ANGELES COUNTY:  69 East San Fernando Valley 0.07 0.07 0.09 0.05 0.05 0.04 -- -- -- -- -- --  72 South Coastal Los Angeles County 0.07 0.07 0.05 0.05 0.04 0.04 0.08 0.03 0.04 0.05 0.04 0.04  84 South Central Los Angeles County 0.11 0.10 0.08 0.06 0.07 0.06 0.05 0.07 0.04 0.09 0.06 0.12  85 South San Gabriel Valley 0.11 0.14 0.10 0.11 0.08 0.06 0.06 0.06 0.05 0.09 0.06 0.05  87 Central Los Angeles 0.09 0.14 0.11 0.07 0.07 0.06 0.06 0.07 0.04 0.07 0.05 0.05  94 Southwest Coastal Los Angeles County 0.06 0.06 0.05 0.04 0.04 0.04 0.03 0.05 0.04 0.04 0.05 0.04 ORANGE COUNTY: 3176 Central Orange County 0.06 0.06 0.03 0.04 0.03 0.04 -- -- -- -- -- -- RIVERSIDE COUNTY: 4144 Metropolitan Riverside County 1 0.05 0.05 0.03 0.04 0.04 0.04 0.04 0.04 0.04 0.05 0.05 0.03 4146 Metropolitan Riverside County 2 0.05 0.06 0.03 0.04 0.03 0.03 0.03 0.04 0.05 0.04 0.03 0.03 SAN BERNARDINO COUNTY: 5175 Northwest San Bernardino Valley 0.05 0.07 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.05 0.05 0.04 5203 Central San Bernardino Valley 0.05 0.05 0.04 0.04 0.04 0.04 0.04 0.04 0.03 0.05 0.05 0.04 

District Maximum 0.11 0.14 0.11 0.11 0.08 0.06 0.08 0.07 0.05 0.09 0.06 0.12 

 * Less than 12 full months of data.  ** Salton Sea Air Basin *** Refer to 2003 AQMP for 1976 to 1989 data
TABLE A-27 

Lead - Highest Monthly Averages, μg/m3***

(To Be Compared to State Standard of 1.5 μg/m3, Monthly Average) 

STN# LOCATION 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2LOS ANGELES COUNTY:  69 East San Fernando Valley 0.08 0.10 0.16 0.05 0.06 0.05 -- -- -- -- -- --  72 South Coastal Los Angeles County 0.09 0.08 0.07 0.06 0.06 0.05 0.08 0.05 0.07 0.06 0.05 0.05 0

 84 South Central Los Angeles County 0.14 0.17 0.11 0.08 0.09 0.07 0.09 0.07 0.04 0.17 0.09 0.23 0 85 South San Gabriel Valley 0.13 0.19 0.15 0.15 0.10 0.07 0.09 0.08 0.07 0.21 0.09 0.07 0 87 Central Los Angeles 0.09 0.21 0.16 0.10 0.11 0.07 0.08 0.07 0.06 0.13 0.06 0.06 0 94 Southwest Coastal Los Angeles County 0.08 0.08 0.05 0.05 0.05 0.04 0.04 0.06 0.06 0.05 0.08 0.04 0

ORANGE COUNTY: 

3176 Central Orange County 0.10 0.08 0.05 0.07 0.06 0.04 -- -- -- -- -- -- RIVERSIDE COUNTY: 4144 Metropolitan Riverside County 1 0.08 0.06 0.03 0.05 0.06 0.04 0.088 0.07 0.08 0.06 0.06 0.04 04146 Metropolitan Riverside County 2 0.08 0.08 0.03 0.04 0.04 0.05 0.05 0.07 0.10 0.05 0.04 0.03 0

SAN BERNARDINO COUNTY: 

5175 Northwest San Bernardino Valley 0.07 0.08 0.04 0.05 0.05 0.06 0.04 0.04 0.05 0.07 0.07 0.05 05203 Central San Bernardino Valley 0.07 0.06 0.05 0.05 0.04 0.05 0.06 0.04 0.05 0.07 0.06 0.05 0

District Maximum 0.14 0.21 0.16 0.15 0.11 0.07 0.09 0.08 0.10 0.21 0.09 0.23 0

 * Less than 12 full months of data.  ** Salton Sea Air Basin *** Refer to 2003 AQMP for 1976 to 1989 data