California Air Resources Board Planning and Technical Support Division Air Quality Analysis Section



# California Air Resources Board’s 2010 Monitoring Network Assessment Report

Prepared for: U.S. EPA Region 9 75 Hawthorne Street San Francisco, CA, 94105



# July 2010i ______________________________________________

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California Air Resources Board’s 201 0 Monitoring Network Assessment Report Executive Summary

This report provides a summary assessment of the am bient air quality monitoring network in certain regions of California. Federal regulations require air quality agencies to conduct a comprehensive assessment ever y five years, beginning in 2010, and forward a report summarizing the findings to the U.S. Environmental Protection Agency (U.S. EPA). This document compri ses the first report, due July 1, 2010.

The purpose of the assessment is to determine if th e network achieves the monitoring objectives specified in federal regulati ons for pollutants with federal ambient air quality standards. These pollutants in clude ozone, PM10, PM2.5, carbon monoxide (CO), nitrogen dioxide (NO2), sulfu r dioxide (SO2), and lead. The regulations require an assessment of whether ex isting monitoring sites are sufficient. They also require an evaluation of any needed changes to PM2.5 population-oriented sites. In addition to the fede ral requirements, this report also provides an evaluation of key needs for implementin g California ambient air quality standards and program requirements.

California has the most severe air quality problem in the nation. Over time, California’s monitoring network has expanded to mee t the increasing challenges of implementing air quality programs to achieve hea lthy air. The current monitoring network exceeds minimum federal requirem ents. Areas that violate or are close to violating the new ozone and PM2.5 stan dards now include most of the rural counties in northern California and in so me instances, even more remote locations near national parks. Therefore, o ur fundamental conclusion is that as federal air quality standards for ozone and PM2.5 have become increasingly more stringent in recent years, monito ring at the sites covered by this report is critical for determining compliance with the new standards. Moreover, monitoring discussed in this report is al so needed for State designation purposes and other State and local moni toring programs.

Monitoring is a shared responsibility between local air districts and the Air Resources Board (ARB). The areas covered by th is report are shown in Table 1. They include all or some of the counties in seven different air basins. These counties span the most rural and sparsely pop ulated counties in northern California.

Areas not included in Table 1, which include all of California’s larger districts, as well as many of the State’s smaller districts, are preparing their own network assessments. The districts expected to submit thei r individual network assessments to Region 9 include: San Francisco Bay Area, South Coast, San Joaquin Valley, San Luis Obispo County, Ventura Cou nty, Monterey Bay Unified, Santa Barbara County, Great Basin Unified, San Dieg o County, Sacramento Metropolitan, North Coast Unified, Mojave Desert, a nd Imperial County

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California Air Resources Board’s 201 0 Monitoring Network Assessment Report 

## Air Basin County (or portions of County) Air District Lake County Lake Lake County AQMD
Lake Tahoe El Dorado (partial) El Dorado County AQMD

Placer (partial) Placer County APCD
Mojave Desert (partial) Kern (partial) Eastern Kern A PCD
Mountian Counties Amador Amador County APCD

Calaveras Calaveras County APCD El Dorado (partial) El Dorado County AQMD Mariposa Mariposa County APCD Nevada Northern Sierra AQMD Placer (partial) Placer County APCD Plumas Northern Sierra AQMD Sierra Northern Sierra AQMD Tuolumne Tuolumne County APCD
North Coast Mendocino Mendocino County AQMD

Sonoma (partial) Northern Sonoma County APCD

Northeast Plateau Lassen Lassen County AQMD

Modoc Modoc County APCD Siskiyou Siskiyou County APCD
Sacramento Valley Butte Butte County AQMD

Colusa Colusa County APCD Glenn Glenn County APCD Placer (partial) Placer County APCD Shasta Shasta County AQMD Solano (partial) Yolo-Solano AQMD Sutter Feather River AQMD Tehama Tehama County APCD Yolo Yolo-Solano AQMD Yuba Feather River AQMD

Note: AQMD = Air Quality Management District APCD = Air Pollution Control District



## Table 1. Areas covered in this report.iii ____________________________________________

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California Air Resources Board’s 201 0 Monitoring Network Assessment Report Table of Contents

Executive Summary........................................................................ i

Introduction.................................................................................. 1

Network Monitoring Objectives... ...................................................... 2

Approach..................................................................................... 3

Federal Monitoring Requirements............ ......................................... 3

Summary of Assessment................................................................ 4

Lake County Air Basin.................................................................... 5

Lake Tahoe Air Basin (portions of El Dorado and Pla cer Counties).......... 6

Eastern Kern Air Pollution Control District (a port ion of the Mojave Desert Air Basin)......................................................................... 7

Mountain Counties Air Basin............................................................. 8 Nevada, Plumas, and Sierra counties.................................... . 9 El Dorado and Placer counties................................. ................ 10 Amador and Calaveras counties............................................. 10 Mariposa and Tuolumne counties......... .................................. 11

Mendocino County Air Quality Management District an d Northern Sonoma Air Quality Management District (a portion o f the North Coast Air Basin)......... ................................................................................. 12 Mendocino County Air Quality Management District......

............... 12 Northern Sonoma Air Quality Management District.........

...... ........ 13

Northeast Plateau Air Basin.............................................................. 1 4

Sacramento Valley Air Basin............................................................. 16 Shasta County...................................................................... 17 Colusa, Glenn, and Tehama counties....................................... 17 Butte County........................................................................ 18 Sutter and Yuba counties....................................................... 18 Yolo County and portions of Placer and Solano coun ties............... 19

Summary....................................................................................... 20

Appendix A.................................................................................... 221 _____________________________________________

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California Air Resources Board’s 201 0 Monitoring Network Assessment Report Introduction

The United States Environmental Protection Agency ( U.S. EPA) finalized amendments to federal monitoring regulations in 200 6. These amendments included requirements for air quality monitoring ag encies to prepare an annual monitoring network plan and to conduct a comprehens ive assessment of its monitoring network every five years. Both the 2010 annual monitoring network plan and the five year network assessment report ar e due on July 1, 2010 to the U.S. EPA. This report summarizes the results of th e network assessment.

The primary requirements for the assessment report are to determine if:

• The monitoring network (network) is meeting the mo nitoring objectives of Appendix D in 40 CFR Part 58;

• Existing sites are no longer needed and can be ter minated;

• New sites and technologies are appropriate; and if

• Any changes are needed to the PM2.5 population ori ented sites.

California has one of the most extensive monitoring networks in the country. Monitoring is routinely conducted at over 250 locat ions. Monitoring is a joint responsibility between air districts, the Air Resou rces Board (ARB), and other agencies including the National Park Service. Beca use of the severity of California’s air quality problems, the number of mo nitors exceeds minimum federal requirements but is critical to implementin g programs to attain federal and State ambient air quality standards.

The assessment is required to cover all pollutants for which the U.S. EPA has established health based air quality standards. Th ese pollutants are ozone (O3), PM2.5, PM10, carbon monoxide (CO), sulfur dioxide ( SO2), nitrogen dioxide (NO2) and lead. This report focuses on the most cr itical pollutants. Ozone and PM2.5 represent California’s most severe air qualit y problems and have the greatest public health impacts. None of the areas in this report currently monitor for SO2 or lead. New federal NO2, SO2 and lead mon itoring requirements will be covered in the 2011 or 2012 annual network repor t.

Separately, thirteen districts, including the large st districts in California, have elected to conduct their own assessment. In some d istricts, the network also includes monitors operated by ARB or the National P ark Service. Districts that have decided to assess their own monitoring network are also responsible for assessing all ARB monitoring sites that are located within the district’s jurisdiction. The network assessment summarized in this report covers the same geographical area covered in the 2010 annual networ k plan and includes the following areas: Lake County Air Basin, Lake Tahoe Air Basin, the eastern Kern2 _____________________________________________

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California Air Resources Board’s 201 0 Monitoring Network Assessment Report County portion of the Mojave Desert Air Basin, Moun tain Counties Air Basin, a portion of the North Coast Air Basin, Northeast Pla teau Air Basin, and the Sacramento Valley Air Basin (minus the sites operat ed by the Sacramento Metropolitan Air Quality Management District). The map illustrates the areas covered by this assessment.

Network Monitoring Objectives

Federal regulations specify the monitoring objectiv es that should be supported for each pollutant by monitors that are part of the State and Local Air Monitoring Stations (SLAMS) network. Note that there are no S O2 or lead monitors operating within the geographic scope of this repor t. As previously noted, this report is limited to a number of ARB, air district and National Park operated sites within the smaller air districts in northern Califo rnia and one in southern California. The ARB assessment includes a site-by- site, monitor-by-monitor evaluation.

One of the most important monitoring objectives is to determine compliance with State and federal air quality standards. As federa l standards have become more3 _____________________________________________

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California Air Resources Board’s 201 0 Monitoring Network Assessment Report stringent recently, having sufficient monitoring to meet this objective is even more critical. Many smaller, primarily rural counties h ave ozone and PM2.5 air quality that approaches or exceeds these new more stringent standards. Other monitoring objectives are also important. Below is a selected summary of typical monitoring objectives.

• Establish compliance with State and federal air qu ality standards

• Monitor sites with expected high concentrations

• Understand historical trends and progress made tow ards standards

• Track spatial distribution of air pollutants

• Evaluate population exposure to air pollutants and have information to inform the public about air quality (AQI)

• Characterize specific geographic locations and emi ssions sources

• Provide air quality data for air quality models an d emission inventory development

• Provide air quality data for determining burn days for agricultural and prescribed burning

• Determine relationship between sources and resulti ng air quality (Sourceapportionment).

• Characterize the extent of pollutant transport.

Approach

This assessment is organized by air basin. An air basin generally has similar meteorological and geographical conditions througho ut with similar air mass. California is divided into 15 air basins to better manage air pollution. We used this approach in the assessment because a network o f monitoring sites within an air basin would likely serve similar monitoring obj ectives. It should be noted that several counties are located in more than one air b asin and the discussion of the monitors is broken out by air basin.

Within each air basin, we conducted an evaluation f or each monitoring site. We considered a number of sources of information inclu ding applicable federal and State requirements, current air quality conditions and attainment status, population, topography and climate. The overall go al was to determine how effectively each site is meeting critical monitorin g objectives. Throughout the assessment, we provide 2009 ozone and PM2.5 federal design values for many sites. However it should be noted that, in some in stances, these design values may include data for potential exceptional events.

Federal Monitoring Requirements

U.S. EPA regulations specify the minimum number of sites at which State and local air agencies must deploy monitors. In practi ce, the State and local agencies find they need to deploy significantly mor e monitors to fulfill State and4 _____________________________________________

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California Air Resources Board’s 201 0 Monitoring Network Assessment Report local monitoring objectives, as well as federal obj ectives. Requirements for the minimum numbers of monitors appear in Appendix D of Part 58 of the CFR. For ozone, PM2.5, and PM10, the required minimum number is based on the population of an area and the severity of the air q uality for the pollutant in the area. For CO and lead, no current monitoring is re quired by Appendix D unless an area exceeds or is close to exceeding a national ambient air quality standard, which is true for very few if any areas in the U.S. New federal monitoring requirements for NO2 and SO2 will be discussed in f uture annual monitoring network plans. For purposes of the minimum require ments, the areas are defined by the metropolitan statistical areas (MSA) developed by the Office of Management and Budget. An MSA may include one or m ore counties. However, not all counties are within an MSA.

All areas in this report meet or exceed federal req uirements. However, additional monitoring is often needed to implement State and l ocal programs designed to attain State air quality standards as expediously a s possible. A summary of the numbers of required and existing monitoring sites i n the geographical scope of this report can be found in Appendix A, located at the end of this report.

Summary of Assessment

California’s extensive network of monitors is neede d due to our severe air quality issues, large population and vehicle miles traveled , varied topography, large number of separate airsheds, and ozone and PM2.5 co ncentrations that are significantly higher than the rest of the country. As a result of this assessment, all existing monitors are critical and none are pro posed to be discontinued or relocated. Under current federal regulations, no a dditional monitors are required in the geographic scope of this report. Any new fe deral monitoring requirements that take effect later in the year or in the next f ew years will be addressed in future annual monitoring network plans. Furthermor e, this assessment demonstrates that the monitors and sites within thi s report meet the monitoring requirements of Appendix D in 40 CFR 58. At the ti me that this report was drafted no additional monitoring is under considera tion.5 _____________________________________________

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California Air Resources Board’s 201 0 Monitoring Network Assessment Report Lake County Air Basin

Lake County is the only county in the Lake County A ir Basin (Basin). It is a rural county located in northern California and borders N apa, Sonoma, Mendocino, Glenn and Colusa counties. It has a population of 65,000, covers 1,327 square miles and includes the towns of Lakeport and Clearl ake.

There is one (each) ozone, PM10, and PM2.5 monitor at Lakeport that is part of the State and Local Air Monitoring Stations (SLAMS) network and two PM10 monitors used in the Geyser Air Monitoring Program (GAMP). Lake County has long attained State and federal air quality standards and has some of the best air quality in the State. In 2009, there were no violations of State or federal ozone, PM10, or PM2.5 standards in the Basin.

However, the 2009 federal 8-hour ozone design value of 0.062 ppm is within the range proposed by U.S. EPA for the revised federal ozone standard (to be finalized in August 2010). As federal standards become increasingly stringent over time, monitoring is cri tical for determining whether an area complies with revised federal standards. Cont inued ozone, PM10 and PM2.5 monitoring is also needed for State designati ons. As shown below, the monitoring objectives in Lake County are to measure high concentrations needed to make designation determinations. Because the cu rrent sites in Lake County are located where the highest concentrations are ex pected to occur and there are no minimum federal requirements, no additional monitoring is needed. No changes to the monitoring network for Lake County a re being considered at this time.

O 3 CO NO 2 PM 2.5 PM 10 cont. PM 2.5 cont. PM 10
Lakeport (060333001) StateD, Gnrl StateD, Gnrl StateD,

Gnrl

Middletown (060333010) StateD, Gamp

Glenbrook (060333011) StateD, Gamp

listed design values in this report may include dat a for potential exceptional events.

Monitoring Objectives:

PopEx = population exposure to pollutant Lake County Air Basin: Lake County

Note: None of the areas discussed in this report ha ve monitors for SO 2 or lead. Moreover,

Bkgrnd = background levels StateD = attainment of State standards Hconc = expected high concentration site Trans = pol lutant transport

Gamp = Geyser Air Monitoring Program Gnrl = general (i.e., public reporting, spatial representation) Trends = trends analysis Rconc = representative concentration site AgBn = agr iculture burning programs Simp = local emission source6 _____________________________________________

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California Air Resources Board’s 201 0 Monitoring Network Assessment Report Lake Tahoe Air Basin (portions of El Dorado and Pla cer counties)

The Lake Tahoe Air Basin (Basin) is the smallest ai r basin in California. It covers approximately 224 square miles and has an estimated population of 58,121 (2010). Part of the Basin is in the State of Nevad a, and part in California. The part that lies in California comprises the eastern part of El Dorado and Placer counties and includes the cities of South Lake Taho e, Tahoe City and Tahoe Vista. Major U.S. Highway 50 runs through the City of South Lake Tahoe.

There is one ozone monitor at the South Lake Tahoe-Airport site located in El Dorado County and it is a seasonal monitor that operates May through October. Although there is no current ozone monitor in the Placer County portion of the Basin, the South Lake Tahoe-Airport site is considered representative of the entire Basin. The area violates the State ozone standard and had one exceedance day in 2009. The 2009 federal 8-hour design value of 0.068 ppm is within the range proposed by U.S. EPA for the revised 8-hour federal ozone standard. The South Lake Tahoe-Airport site is needed for State and federal designations.

The continuous PM10 monitor at the South Lake Tahoe-Sandy Way site is used for public reporting and spatial representation as well as for State designation purposes. The area violates the State 24-hour PM10 standard and had one State exceedance day in 2009. The Basin is current ly nonattainment for the State PM10 standard. This site is the only PM10 si te in the Basin. For these reasons, the PM10 monitor is also needed.

The current sites in the El Dorado County portion o f the Basin are part of the Sacramento-Arden-Arcade-Roseville MSA and are locat ed where the highest concentrations are expected to occur. No additiona l monitoring is required in the MSA and no changes to the monitoring network in the Basin are being considered at this time.

O 3 CO NO 2 PM 2.5 PM 10 cont. PM 2.5 cont. PM 10

South Lake Tahoe-Airport (060170013) StateD, Trans, Hconc
South Lake Tahoe-Sandy Way (060170011) Grnl

Lake Tahoe Air Basin: Portions of El Dorado and Pla cer Counties7 _____________________________________________

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California Air Resources Board’s 201 0 Monitoring Network Assessment Report Eastern Kern Air Pollution Control District (a port ion of the Mojave Desert Air Basin)
This section covers the monitoring sites located in the Eastern Kern Air Pollution Control District (District). The District comprise s the eastern portion of Kern County and is one of three districts located in the Mojave Desert Air Basin (Basin). The other two districts in the Basin will be included in a separate assessment prepared by the Mojave Desert Air Qualit y Management District.

The District is located in the northwestern corner of the Basin and separated, to the south, from the South Coast Air Basin by the An telope Valley and San Gabriel Mountains. The Tehachapi and the Sierra Ne vada Mountains separate it from the San Joaquin Valley, to the west and north. Directly to the east is San Bernardino County. Eastern Kern’s population o f 147,758 (2010) resides primarily in and around the major towns, including Tehachapi, Rosamond, Boron and Mojave. Major highways are U.S. Highways 58, 1 4, and 395.

The ozone monitor at the MojavePoole site is the only ozone monitor in the District. In 2009, 32 days and 61 days exceeded the federal and State 8-hour ozone standards, respectively. The 2009 federal 8-hour ozone design value of 0.084 ppm is well above the level proposed by U.S. EPA for the revised 8-hour federal ozone standard. This site is critical for both federal and State ozone designation purposes.

The PM2.5 monitors at the Mojave-Poole Street and Ridgecrest-California Street sites are used for collecting data at expected high and representative concentration sites. The District is designated as an unclassified area for both State and federal PM2.5 standards. F ederal 2009 PM2.5 annual average and 24-hour design values for the District are 6.1 ug/m 3 and 16 ug/m 3

, respectively. As federal and State PM standards be come increasingly more stringent, monitoring becomes more critical for dem onstrating whether an area complies with these revised standards.

The PM10 monitors at the Mojave-Poole Street and Ri dgecrest-California Street sites are used for collecting data at expected high and representative8 _____________________________________________

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California Air Resources Board’s 201 0 Monitoring Network Assessment Report concentration sites. The Canebrake site started on January 1, 2009 and is used for monitoring regional PM10 concentration levels i n the area and for demonstrating compliance with the federal standard. This portion of eastern Kern County is currently a nonattainment area for P M10. For these reasons, continued PM10 monitoring is needed in the District . Note that the District recently started ozone and meteorological monitorin g at Tehachapi for the evaluation of transport. However, there are no dat a reported from this site into the Environmental Protection Agency’s Air Quality S ystem (AQS) at the time this report was drafted.

The current sites in the District are part of the B akersfield MSA and the majority of sites are located where the highest concentratio ns are expected to occur. No additional monitoring is required in the MSA and no changes to the monitoring network in the District are being considered at thi s time.

O 3 CO NO 2 PM 2.5 PM 10 cont. PM 2.5 cont. PM 10

Canebrake (060290017) Rconc

Mojave-Poole (060290011) Hconc, Trans Hconc Hconc

RidgecrestWest California (060290015) Rconc Hconc

Mojave Desert Air Basin: Eastern part of Kern Count y

Mountain Counties Air Basin

The Mountain Counties Air Basin (Basin) extends from Plumas County in the north to Mariposa County in the south, and also includes all of Sierra, Nevada, Amador, Calaveras, Tuolumne, and Mariposa counties, and portions of Placer and El Dorado counties. The Basin covers the central and northern parts of the Sierra Nevada Mountains. The elevation ranges from several hundred feet in the foothills along the western edge of the Basin to more than 10,000 feet along the Sierra crest. Although bordering the Sacramento urban area to the west, the Basin is predominately rural, with a total population of 472,991 (2010).9 _____________________________________________

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California Air Resources Board’s 201 0 Monitoring Network Assessment Report Despite its rural character, the Basin includes all or part of four nonattainment areas for the federal 1997 ozone standard. Three n onattainment areas are completely contained within the Basin: Central Moun tain Counties (Amador and Calaveras counties), Southern Mountain Counties (Tu olumne and Mariposa counties), and Western Nevada County (a portion of Nevada County). Furthermore, El Dorado and Placer counties have lon g been part of the Sacramento Metro ozone nonattainment area because t hey are linked to the Sacramento urban area through travel, employment an d housing patterns.

Most of the Basin is either attainment or unclassif iable for the federal 2006 24-hour PM2.5 standard. A portion of El Dorado County is include d in the Sacramento PM2.5 nonattainment area. (A portion of the Placer Count y is also included in the nonattainment area, but this portio n lies in the Sacramento Valley rather than Mountain Counties Air Basin.)

There are a variety of monitoring objectives in the Basin. These objectives include collecting data at expected high concentrat ion sites, providing data for agriculture burn decisions, evaluation of ozone tra nsport and for educating the public about air quality. Some sites also collect representative and background concentration data. All of the monitors in the Bas in provide data to implement a variety of federal and State programs. We did not identify any new or unmet monitoring needs.

The current sites in the El Dorado and Placer count ies portion of the Basin are part of the Sacramento-Arden-Arcade-Roseville MSA. No other counties in the Basin are part of an MSA. No additional monitoring is required in the MSA or in any part of the Basin and no changes to the monitor ing network in the Basin are being considered at this time. A summary of the mo nitors and their objectives accompanies each of the tables below.

Nevada, Plumas, and Sierra counties There are more PM2.5 than ozone monitors in this no rthernmost part of the Basin. These monitors provide data for general use s, designation purposes, and to help assess potential wood smoke impacts and are located at potentially high concentration sites. In addition, the Plumas Count y 2009 PM2.5 design value is near the daily federal PM2.5 standard. The Grass V alley site is the most comprehensive, and includes monitors for O3, NO2, a nd PM2.5. Nevada County is nonattainment for the federal ozone standard and had a 2009 8-hour ozone design value of 0.087 ppm with 18 federal exceedanc e days in 2009. The White Cloud Mountain site is operated by the ARB and help s characterize air quality in the eastern portion of the ozone nonattainment area . Ozone concentrations at this site also violate the current federal and Stat e ozone standards. Ozone monitoring at Truckee restarted on July 1, 2010 and the data will be submitted into AQS. Ozone monitoring in Penn Valley in Nevad a County and PM10 monitoring in Loyalton in Sierra County are not rep orting data into AQS. These non-AQS monitors are used for local monitoring purp oses.10

___________________________________________________ _________________ California Air Resources Board’s 201 0 Monitoring Network Assessment Report O 3 CO NO 2 PM 2.5 PM 10 cont. PM 2.5 cont. PM 10

Chester (060631007) StateD, Gnrl

Grass Valley (060570005) Hconc, Rconc, StateD Rconc, StateD Rconc StateD, Gnrl

Portola (060631009) Hconc StateD, Gnrl Quincy (060631006) Hconc StateD, Gnrl

Truckee (060571001) Hconc Hconc StateD, Gnrl
White Cloud Mountain (060570007) StateD Mountain Counties Air Basin: Nevada, Plumas and Si erra Counties

El Dorado and Placer counties El Dorado and Placer counties both split their land area among one or more air basins. A part of the El Dorado County is also in the Lake Tahoe Air Basin and Placer County is split into three air basins (Lake Tahoe, Mountain Counties, and Sacramento Valley). The Mountain Counties Air Basi n portions of El Dorado and Placer counties are part of the Sacramento Metro no nattainment area for the federal 1997 ozone standard. Consequently, identif ying areas of high ozone concentration is the primary monitoring objective w ithin this part of the Basin. Cool has been the high ozone site during several di fferent ozone seasons and had a 2009 federal 8-hour ozone design value of 0.0 93 ppm. Echo Summit was established to characterize the extent of air pollu tant transport from the Sacramento and San Joaquin Valleys up the western s lope of the Sierra Nevada. This area is currently nonattainment for the State 24-hour PM10 standard. For these reasons, continued ozone and PM10 monitoring in El Dorado and Placer counties is needed.

O 3 CO NO 2 PM 2.5 PM 10 cont. PM 2.5 cont. PM 10

Colfax (060610004) Hconc,

StateD

Cool-Hwy 193 (060170020) Hconc,

Trans, StateD
Echo Summit (060170012) Hconc, Trans

PlacervilleGold Nugget (060170010) Hconc, Trans Hconc Mountain Counties Air Basin: Portions of El Dorado and Placer Counties

Amador and Calaveras counties Amador and Calaveras counties comprise the Central Mountain counties nonattainment area for the federal 1997 ozone stand ard. Two ozone monitors track the area’s progress toward attaining the stan dard. The San Andreas site is the 2009 federal design site for the federal 8-hour ozone nonattainment area and11

___________________________________________________ _________________ California Air Resources Board’s 201 0 Monitoring Network Assessment Report had a 2009 federal 8-hour ozone design value of 0.0 82 ppm. Though neither county is part of a federal PM2.5 or PM10 nonattain ment area, the monitors in San Andreas help us understand representative conce ntrations in that area and are used for State designation purposes.

O 3 CO NO 2 PM 2.5 PM 10 cont. PM 2.5 cont. PM 10

JacksonClinton Road (060050002) Hconc,

Trans, StateD

San Andreas (060090001) Hconc, Trans, StateD Rconc Rconc Mountain Counties Air Basin: Amador and Calaveras C ounties

Mariposa and Tuolumne counties Mariposa and Tuolumne counties comprise the Souther n Mountain counties nonattainment area for the federal 1997 ozone stand ard. They also violate the State ozone standards. The area had a 2009 federal 8-hour ozone design value of 0.086 ppm with more than 10 days in 2009 that ex ceeded the federal ozone standard. The ozone sites are critical in determin ing compliance with federal and State ozone standards. The ozone monitor at the Yo semite-Turtleback site is operated by the National Park Service. The Sonora and Yosemite-Turtleback sites are the 2009 federal ozone design sites in th e southern portion of the Basin.

While there were no days that exceeded the federal 24-hour PM10 standard in 2009, three days exceeded the State 24-hour PM10 st andard. A portion of Mariposa County is nonattainment for the State PM10 standard. This area is unclassifiable for both federal and State PM2.5 sta ndards. The continuous PM2.5 monitor at the Yosemite Village site is used for State designation purposes as well as public reporting, smoke monitor ing and spatial representation. For these reasons, continued PM2.5 and PM10 monitoring is needed at the Yosemite Village site, which is opera ted by ARB.

O 3 CO NO 2 PM 2.5 PM 10 cont. PM 2.5 cont. PM 10
Jerseydale (060430006) Hconc, Trans

Sonora (061090005) Hconc, StateD

YosemiteTurtleback (060430003) Hconc, Trans, StateD
Yosemite Village (060431001) Hconc StateD, Gnrl Mountain Counties Air Basin: Mariposa and Tuolumne Counties12

___________________________________________________ _________________ California Air Resources Board’s 201 0 Monitoring Network Assessment Report Mendocino County Air Quality Management District an d Northern Sonoma Air Quality Management District (a portion of the N orth Coast Air Basin)

This section covers monitoring in the Mendocino Cou nty Air Quality Management District and the Northern Sonoma Air Quality Manage ment District. These two districts cover the entire portion of Mendocino Cou nty and the portion of Sonoma County located in the North Coast Air Basin (Basin) . The other three counties in the Basin are covered in a separate assessment repo rt prepared by the North Coast Unified Air Quality Management District (Humb oldt, Del Norte, and Trinity).

Stretching along the northern coastline of California, the Basin covers 12,339 square miles and is home to giant coastal redwood trees that are found nowhere else in the world. The Mendocino, Humboldt, Trinity, Del Norte, and northern part of Sonoma counties lies within the Basin boundary, which borders the State of Oregon directly to the north, the Sacramento Valley and Northeast Plateau air basins to the west, and the San Francisco Air Basin to the south. The Basin’s population of 333,829 (2010) resides primarily in and around major towns, including Crescent City, Eureka, Fort Bragg, Ukiah, Willits, and Healdsburg. Major highways are U.S. Highways 101 and 1.

While the current sites in the Mendocino County Air Quality Management District are not part of an MSA, the current sites in the No rthern Sonoma Air Quality Management District are part of the Santa Rosa-Peta luma MSA. The majority of sites in both districts are located where the highe st concentrations are expected to occur. No additional monitoring is required in the MSA and no changes to the monitoring network in the districts are being consi dered at this time.

Mendocino County Air Quality Management District There is only one ozone monitor in Mendocino County , at Ukiah-Gobbi Street. Ozone monitoring at the Willits-Main Street site wa s suspended in 2008. Ozone concentrations at the Willits-Main Street site were lower than ozone concentrations at the Ukiah-Gobbi Street site and w ere below the range of the proposed federal ozone standard. However, the 2009 federal 8-hour design value of 0.062 ppm at Ukiah-Gobbi Street is within the range proposed by U.S.13

___________________________________________________ _________________ California Air Resources Board’s 201 0 Monitoring Network Assessment Report EPA for the revised 8-hour federal ozone standard. For this reason, continued ozone monitoring is critical at the Ukiah-Gobbi Str eet site.

PM2.5 and PM10 monitoring in Mendocino County are m ainly used for collecting data at expected high and representative concentrat ion sites. The District discontinued three filter-based PM10 monitors and o ne filter-based PM2.5 monitor in 2008 and started two continuous PM2.5 FE Ms and one continuous PM10 FEM monitor in 2009. Data from the continuous PM2.5 and PM10 monitors are reported into AQS. Due to the recent establishment of the continuous FEM PM monitors in the county, continued PM monitoring is needed to have more completed data for regulatory purposes , including State designations. Mendocino County is currently nonatt ainment for the State 24-hour PM10 standard.

Carbon monoxide monitors at the Ukiah-Gobbi Street and Willits-Main Street sites were discontinued in 2008, along with the nit rogen dioxide (NO2) monitor at Willits-Main Street in Mendocino County. Carbon mo noxide concentrations in the District were well below both federal and State sta ndards. Currently, there is only one NO2 monitor left operating in Mendocino Co unty, which is located at the Ukiah-Gobbi Street site. The NO2 monitor provides useful information on ozone precursors and for evaluating transport. Further e valuation of NO2 monitoring needs will be discussed in the 2012 annual network report.

Northern Sonoma Air Quality Management District One ozone monitor exists in the northern part of So noma County that lies within the North Coast Air Basin. This portion of the cou nty comprises the Northern Sonoma County Air Quality Management District (Dist rict). This District attains State and federal ozone standards. The 2009 federa l 8-hour ozone design value is 0.056 ppm. The ozone monitoring site is the onl y ozone monitor in the county and is needed for determining compliance with State and federal standards. The ozone monitor is also needed to characterize transp ort. For these reasons, continued ozone monitoring is needed at the Healdsb urg-Airport site.

Currently, there are three PM10 monitoring sites in the District. The District had expressed interest in discontinuing all filter-base d PM10 monitoring and establishing continuous PM10 monitoring. The ARB i s coordinating with the District in this effort. This area had attained th e State PM10 standard and is listed as unclassified under federal standards; how ever, continued PM10 monitoring is needed in the area to maintain State compliance.14

___________________________________________________ _________________ California Air Resources Board’s 201 0 Monitoring Network Assessment Report O 3 CO NO 2 PM 2.5 PM 10 cont. PM 2.5 cont. PM 10

Cloverdale (060970001) Rconc

Fort Bragg (060450002) Hconc, StateD

Guerneville (060973002) Rconc

HealdsburgAirport (060971003) Rconc,

StateD

HealdsburgMatheson (060970002) Rconc

Ukiah-County Library (060450006) Hconc, StateD

Ukiah-Gobbi Street (060450008) Hconc,

Trans, StateD Rconc Rconc

WillitsFirehouse (060452001) Hconc, StateD North Coast Air Basin: Mendocino County and the no rthern part of Sonoma County

Northeast Plateau Air Basin

The Northeast Plateau Air Basin (Basin) is located in the remote northeast corner of California and comprises Lassen, Modoc, and Siskiyou counties. The northern part of the Basin has lofty volcanic peaks, such as Mount Shasta and Mount Lassen. To the south and west, forested mountains dominate the Basin. The Basin covers approximately 14,788 square miles and is bordered by the states of Oregon directly to the north and Nevada to the east. The Basin’s population of 92,112 (2010) predominately resides in rural towns, including Yreka, Mount Shasta, Alturas, and Susanville. Major highways are U.S. Highways 5, 97, and 395.15

___________________________________________________ _________________ California Air Resources Board’s 201 0 Monitoring Network Assessment Report While there are three monitoring sites in Siskiyou County, there are no monitoring sites in Lassen and Modoc counties. Las sen and Modoc counties have long attained the federal and State ozone stan dards. The City of Yreka, located in Siskiyou County, is the largest populate d area in the Basin and represents an area of expected high concentrations within the Basin. For this reason, ARB believes that Siskiyou County adequatel y represents the entire Basin. This section describes the monitoring objec tives for the ozone, PM10, and PM2.5 monitors in Siskiyou County.

There is only one ozone monitor located at Yreka in Siskiyou County. Siskiyou County is currently designated nonattainment-transi tional for the State ozone standard. Siskiyou County has made dramatic progre ss towards attainment of the State ozone standard. In 2009, no days exceede d either the federal or State 8-hour ozone standard at the site. However, the 20 09 federal 8-hour ozone design value of 0.061 ppm is within the range propo sed by U.S EPA for the revised 8-hour federal ozone standard. This site i s needed for determining compliance with State and federal ozone standards. For this reason, continued ozone monitoring at the Yreka site is needed.

There are three PM10 monitoring sites in Siskiyou C ounty. While the Yreka and Mount Shasta sites are operated by the District, th e Lava Beds National Monument site is operated by the National Park Serv ice. The area had attained the federal 24-hour PM10 standard, however, PM10 co ncentrations in the last three years exceeded the State 24-hour PM10 standar d. Continued PM10 monitoring is needed for State designation purposes

.
In 2007, the PM2.5 monitor at the Yreka site was in operable and no data were reported in that year. The PM2.5 monitor was reest ablished at the site in 2008 and two years of PM2.5 data were reported into AQS. While PM2.5 concentrations in the area are below both federal a nd State PM2.5 standards, continued monitoring of the PM2.5 monitor is needed to have more complete data for designation purposes. Because the majorit y of sites in Siskiyou County are located where the highest concentrations are ex pected to occur and there are no minimum federal requirements, no additional monitoring is needed and no changes are being proposed to the monitoring listed below.

O 3 CO NO 2 PM 2.5 PM 10 cont. PM 2.5 cont. PM 10

Lave Beds (060930005) Hconc

Mount Shasta (060930004) Rconc

Yreka (060932001) Hconc,

Trans, StateD Hconc Hconc Northeast Plateau Air Basin: Siskiyou County16

___________________________________________________ _________________ California Air Resources Board’s 201 0 Monitoring Network Assessment Report Sacramento Valley Air Basin The Sacramento Valley Air Basin (Basin) comprises t he Sacramento urban area in the south and stretches northward for more than 150 miles. The Basin includes nine complete counties—Butte, Colusa, Glen n, Sacramento, Shasta, Sutter, Tehama, Yolo, and Yuba—and portions of two others—Solano and Placer. The Basin is a valley, ringed on three sid es by significant mountain ranges—the California Coastal Range to the west, the Sierra Nevada Mountains to the east, and the Cascade Range to the north.

The Basin is home to more than 2.5 million people, the majority of whom live in the Sacramento Metro ozone nonattainment area portion of the Basin. The rest are scattered among smaller cities to the north (Yuba City, Marysville, Chico, and Redding) as well as smaller towns and communities.

There are multiple air quality concerns in this region. Butte, Sacramento, Yolo and the portions of Placer and Solano counties located in the Basin are currently designated nonattainment for federal and State ozon e standards. Most of the other counties have federal 8-hour ozone design val ues within the range proposed for the revised 8-hour federal ozone stand ard and violated the State ozone standard. While most of the counties (exclud ing Butte and Sacramento) either had attained or are unclassifiable for the S tate PM2.5 standard, several areas in the Basin are nonattainment for the federa l PM2.5 standard. All counties in the Basin are designated nonattainment for the State PM10 standard.

The Basin includes five MSAs: Chico, Redding, Sacra mento-Arden-ArcadeRoseville, Vallejo-Fairfield, and Yuba City. No ot her counties in the Basin are part of an MSA. There are a variety of monitoring objectives in the Basin. These objectives include collecting data at expected high concentration sites, providing data for agriculture burn decisions, evaluation of ozone transport and for educating the public about air quality. Some sites also collect representative and background concentration data. All of the monitors in the Basin provide data to implement a variety of federal and State programs. We did not identify any new or unmet monitoring needs.

No additional monitoring is required in the MSA or in any part of the Basin and no changes to the monitoring network in the Basin are being considered at this time. Specific monitors and monitoring objectives are des cribed below. The Sacramento Metropolitan Air Quality Management Dist rict is conducting their own17

___________________________________________________ _________________ California Air Resources Board’s 201 0 Monitoring Network Assessment Report assessment; therefore, monitors located in Sacramen to County are not discussed in this report.

Shasta County Shasta County has a mix of ozone and PM2.5 and PM10 monitors, most of which are intended to measure potential high pollutant va lues. Shasta County is designated as nonattainment for the State ozone sta ndard as well as the State PM10 standard. Shasta County currently is designat ed attainment for the State PM2.5 standard. However, the continuous PM2.5 moni tor is needed for agricultural burn forecasting and general purposes.

Shasta County had a 2009 federal 8-hour ozone desig n value of 0.76 ppm and exceeded federal and State ozone standards more tha n five days in 2009. The Anderson and Redding sites are critical for determi ning compliance with State and federal ozone standards. The Lassen site is op erated by the National Park Service and provides useful data for evaluating tra nsport and background ozone concentrations.

O 3 CO NO 2 PM 2.5 PM 10 cont. PM 2.5 cont. PM 10

Anderson (060890007) Hconc,

StateD Hconc StateD, Gnrl

Lassen Volcanic NP (060893003) Rconc

Redding (060890004) Hconc,

StateD Hconc Hconc

Shasta Lake (060890008) Rconc

Sacramento Valley Air Basin: Shasta County

Colusa, Glenn and Tehama counties These counties have a mix of particulate matter and ozone monitors, most are designed to monitor potential high concentrations. However, the Colusa and Willows’ continuous PM2.5 monitors help inform agri cultural burning decisions, which are important considering that this area has a significant amount of agricultural land. None of these counties are curr ently designated nonattainment for the federal ozone or PM2.5 standards. The area ’s 2009 federal 8-hour ozone design values range from 0.062 ppm to 0.082 ppm, wh ich is within the range proposed by U.S. EPA for the revised 8-hour federal ozone standard. Moreover, this area is currently nonattainment for the State 24-hour PM10 standard. Continued ozone and PM monitoring is needed for det ermining compliance with State and federal standards, as well as agriculture burn forecasting.18

___________________________________________________ _________________ California Air Resources Board’s 201 0 Monitoring Network Assessment Report Ozone CO NO2 PM2.5 PM10 cont. PM2.5 cont.

PM10
Colusa (060111002) Rconc, StateD Hconc Hconc StateD, AgBn
Red BluffMesser Drive (061030002) Hconc

Red Bluff-Oak Street (061030005) Hconc, StateD

Tuscan Butte (061030004) Hconc, Trans, StateD
Willows (060210003) Hconc, StateD Hconc StateD, AgBn Sacramento Valley Air Basin: Colusa, Glenn and Teh ama Counties

Butte County Butte County is currently designated nonattainment for the federal 1997 ozone standard and a portion of Butte County is nonattain ment for the federal 2006 24-hour PM2.5 standard. The county had a 2009 fede ral 24-hour PM2.5 design value of 59 ug/m 3 . The Paradise-Airport site is the ozone design si te with a 2009 federal 8-hour design value of 0.082 ppm. With air quality challenges for both pollutants, multi-pollutant monitoring is needed at the Chico site. PM2.5 monitors at the Gridley and Paradise – Fire Station sites al so help inform agricultural burning decisions, which is important in this regio n, as well as characterizing impacts from residential wood burning. Butte Count y is currently nonattainment for the State 24-hour PM10 standard. Continued mon itoring in Butte County is needed.

O 3 CO NO 2 PM 2.5 PM 10 cont. PM 2.5 cont. PM 10

Chico (060070002) Hconc Rconc Rconc Hconc Hconc StateD, Gnrl Gridley (060007004) StateD, AgBn

ParadiseAirport (060074001) Hconc

Paradise-Fire Station (060072001) StateD, AgBn Sacramento Valley Air Basin: Butte County

Sutter and Yuba counties Both counties are designated nonattainment for the State ozone standard. In addition, a portion of Sutter County is part of the Sacramento federal ozone nonattainment area. Sutter County had a 2009 8-hou r ozone design value of 0.079 ppm, which is above the federal 8-hour ozone standard. In addition, portions of Sutter and Yuba counties comprise their own nonattainment area for the federal 24-hour PM2.5 standard. While this are a currently meets this standard, PM2.5 monitoring is needed to demonstrate continued attainment. Both ozone and particulate matter monitoring in thi s area is very important.19

___________________________________________________ _________________ California Air Resources Board’s 201 0 Monitoring Network Assessment Report Yuba City, located in Sutter County, and Marysville , located in Yuba County, are adjacent to one another, form one combined metropol itan statistical area, and function more like one city than two. Consequently , although there is no monitor physically in Yuba County, the Yuba City site in Su tter County is considered representative of both Yuba City and Marysville, an d therefore functions to represent Yuba County, as well. The Sutter Buttes site was established to characterize ozone transport aloft in the Sacrament o Valley. This area is currently nonattainment for the State 24-hour PM10 standard. Continued monitoring at the Sutter Buttes and Yuba City sites is needed.

Ozone CO NO2 PM2.5 PM10 cont. PM2.5 cont.

PM10
Sutter Buttes (061010004) Hconc,

Trans Yuba City (061010003) Hconc,

StateD Rconc Hconc Hconc StateD, AgBn Sacramento Valley Air Basin: Sutter and Yuba Count ies

Yolo County and portions of Placer and Solano count ies All of these counties are nonattainment for the fed eral and State ozone standards. Solano and Yolo counties have monitors with 2009 federal 8-hour ozone design values exceeding 0.070 ppm. In additi on, Yolo County and the Sacramento Valley portions of Placer and Solano cou nties are all part of the Sacramento federal ozone nonattainment area. Addit ionally, portions of Yolo and Solano counties and the Sacramento Valley porti on of Placer are part of the Sacramento nonattainment area for the State 24-hour PM2.5 and PM10 standards. With multiple air quality challenges, a comprehensive monitoring strategy is important for these areas. Consequentl y, four out of the seven monitor sites in this area monitor for two or more pollutants. As standards tighten and become more stringent, continued monitoring in these counties becomes even more important. Moreover, with agricultural l ands being the predominate land use in and around these counties, monitoring P M2.5 for purposes of agricultural burning forecasts is also important.20

___________________________________________________ _________________ California Air Resources Board’s 201 0 Monitoring Network Assessment Report O 3 CO NO 2 PM 2.5 PM 10 cont. PM 2.5 cont. PM 10

Auburn (060610002) Hconc

Davis-UCD Campus (061130004) Hconc Rconc Rconc StateD, AgBn

Roseville (060610006) Hconc Rconc Rconc Hconc StateD, AgBn

West Sacramento (061132001) Hconc

Woodland (061131003) Hconc,

StateD Hconc Hconc StateD, AgBn
VacavilleMerchant (060953001) Rconc

VacavilleUlatis (060953003) Hconc,

Trans, StateD StateD, Gnrl Sacramento Valley Air Basin: Yolo County, part of Placer County, and

northern and eastern parts of Solano County

Summary

California has one of the most extensive monitoring networks in the nation. Such a network is needed due to our severe air quality i ssues, large population and vehicle miles traveled, varied topography and a lar ge number of separate airsheds. There are more than 250 monitoring locat ions in California where the ambient air quality is routinely measured for gaseo us and particulate air pollutants. The measured data form a backbone for air quality management programs, provide the public with information on th e status of air quality and progress in improving air quality, and are used by health researchers, business interests, environmental groups, and others. As a result of this assessment, all existing monitors covered in this report are critic al and none is proposed to be discontinued or relocated. Moreover, this assessme nt demonstrates that the monitors and sites within this report meet the moni toring objective requirements of Appendix D in 40 CFR 58, which is to provide air pollution data to the general public in a timely manner and to support compliance with ambient air quality standards and air pollution research studies.21

___________________________________________________ _________________ California Air Resources Board’s 201 0 Monitoring Network Assessment Report (This page intentionally left blank)22

___________________________________________________ _________________ California Air Resources Board’s 201 0 Monitoring Network Assessment Report This appendix provides a summary of the required an d existing monitoring sites within the geographical scope of this report.

APPENDIX A

Required Existing Required Existing Required Existing Req uired Existing Required Existing
FRM FRM Continuous Continuous FRM FRM Continuous Continuou s

67,530 0 1 0 1 0 0 0 1 0 0

58,121 0 1 0 0 0 0 0 0 0 1

2 16 3 5 2 6 4 9 0 3

147,758 0 1 0 2 0 0 0 3 0 0

2 9 2 5 1 3 2 6 0 1

472,991 0 11 0 5 0 6 0 3 0 0

2 16 3 5 2 6 4 9 0 3

333,829 0 2 0 0 0 2 0 3 0 1

1 2 0 1 0 0 0 3 0 0

92,112 0 1 0 1 0 0 0 3 0 0

2,817,815 0 16 0 6 0 11 0 13 0 0

1 2 1 1 1 3 0 1 0 0

1 3 0 1 0 0 0 3 0 0

2 16 3 5 2 6 4 9 0 3

2 4 1 1 1 2 0 2 0 0

1 2 1 1 1 1 0 1 0 0

1 Federal minimum monitoring requirements for an are a is by Metropolitan Statiscal Area (MSA). However

, for the purpose of this assessment, we are listing the number of required and existing monitoring site s by the geographical areas that are covered in this report. Note that there are more monitoring sites in the geographical scope of this report than required by federal regulations. New federal monitoring requir ements for NO2 and SO2 will be discussed in future annual monitoring network plans. There are no federal requirements for CO and lead monitoring within the geographical scope of this report.

* Parts of these MSAs are included in the geographi cal scope of this report, and parts are within the geographical scope of the reports being completed b y the districts. The numbers of sites listed are f or the entire MSA. Sacramento Valley Air Basin (minus Sacramento Metro AQMD)

Redding MSA Lake County Air Basin

Sacramento-Arden-ArcadeRoseville MSA*

Bakersfield MSA*

Sacramento-Arden-ArcadeRoseville MSA*

Yuba City MSA Lake Tahoe Air Basin (portions of El Dorado and Placer counties)

Eastern Kern Air Pollution Control District ( a portion of Mojave Desert Air Basin)

Mountain Counties Air Basin

Mendocino County and Northern Sonoma Air Quality Management Districts

Vallejo-Fairfield MSA* Chico MSA

Sacramento-Arden-ArcadeRoseville MSA* Northeast Plateau Air Basin

Santa Rosa-Petaluma MSA*

Numbers of Required and Existing Sites in the Geogr aphical Areas of this Report 1

Geographical Area/ MSA Pop. Ozone PM2.5 PM10