# Utah Area Designation

Recommendations for the 2008 Ozone NAAQS

State of Utah Department of Environmental Quality Division of Air Quality

150 North 1950 West

P.O. Box 144280 Salt Lake City, Utah 84114-4820

801-536-4000

March 20092 

## Table of Contents

Purpose........................................................................................................................ .................... 4

Overview of Ozone in Utah ...................................................................................................... ...... 4 Regional Ozone................................................................................................................. .............. 8 Regulatory Background .......................................................................................................... ...... 10 Applicable Guidance............................................................................................................ ......... 11 Document Organization.......................................................................................................... ...... 12

Discussion of EPA Guidance Factors........................................................................................... 12 Factor 1: Air Qual ity Monitoring Data ............................................................................... 12

Factor 2: Em ission Data...................................................................................................... 1 5 Factor 3: Population Density .............................................................................................. 18 Factor 4. Traffic and Commuting Patterns ......................................................................... 20

Factor 5. Growth Rates and Patterns................................................................................... 22 Factor 6. Meteorology......................................................................................................... 24 Factor 7. Geography/Topography....................................................................................... 25

Factor 8. Jurisdictional Boundaries..................................................................................... 28

Factor 9. Level of Control of Emission Sources................................................................. 32

Consideration of Additiona l Areas outside the Wasatch Front Core Area................................... 35 Park City, Summit County................................................................................................... 35 Heber Valley, Wasatch County............................................................................................ 37 Tooele Valley, Tooele County............................................................................................. 38 Brigham City, Box Elder County......................................................................................... 40 Utah County............................................................................................41 St. George, Washington County .......................................................................................... 43 San Juan County ................................................................................................................ .. 44

State Recommendations.......................................................................................................... ...... 47

Wasatch Front .................................................................................................................. .... 47

Attainment/Unclassifiable Areas ......................................................................................... 48 Summary Table.................................................................................................................. .. 49 Supporting Documentation ....................................................................................................... .... 50

For nonattainmen t areas:...................................................................................................... 5 0

For attainment/unclassifiabl e and nonattainment areas:...................................................... 50

Names of contacts.............................................................................................................. ........... 51

Appendix 1..................................................................................................................... ............... 52

Appendix 2..................................................................................................................... ............... 543 

## Table of Figures

Figure 1. Utah’s Wasatch Front .............................................................................................. ......5 Figure 2. Population Density in Utah ......................................................................................... .. 6 Figure 3. Population Density with CSA and MSA Overlay ..........................................................6 Figure 4. Mean Summertime Afternoon Surface Background Ozone Concentration...................8 Figure 5. Utah’s Air Monitoring Network...................................................................................13 Figure 6. Percentage of VOC and NO

x produced along the Wasatch Front................................16 Figure 7. VOC Projections through 2014 ....................................................................................17 Figure 8. NO

x Projections through 2014......................................................................................17 Figure 9. Population Density (Wasatch Front) with Counties and Topography..........................19 Figure 10. Population Density and Area Roadways ......................................................................22 Figure 11. Wasatch Front Topography ..........................................................................................26 Figure 12. Emissions in Relation to the Core Nonattainment .......................................................34 Figure 13. Oil and Gas Production in San Juan County, Utah .....................................................45 Figure 14. Recommended Ozone Nonattainment Areas................................................................47 Figure 15: Statewide Area Map .................................................................................................. ...48



## Table of Tables

Table 1. Ozone Concentrations fr om Official Utah DAQ Monitors ..........................................14

Table 2. Ozone Concentrations from Na tional Park Service (CASTNet) Monitors ...................15

Table 3. Ozone Precursor Emissions ........................................................................................... 15 Table 4. Population Densities in Counties be ing considered as poten tial candidates for

Nonattainment Areas ........................................................................................... .........18 Table 5. Traffic and Commuting Patterns ...................................................................................20 Table 6. Projected Population Growth (2000-2020) ...................................................................23 Table 7. Projected Annual VMT Growth in Greater Wasatch Front Area (Millions) ................24 Table 8. Elevations of Valley Floor and Adjacent Mountains along the Wasatch Front ............27 Table 9. Description of all Areas of Utah and Recommended Designations .............................49 Table 10. DAQ Monitor Network Locations ...............................................................................504 

## Purpose

The purpose of this document is to provide Utah’s recommendation regarding area designations for the revised National Ambient Air Quality Standa rd (NAAQS) for ozone which was developed under section 109 of the Clean Air Act (CAA) on March 12, 2008.



## Overview of Ozone in Utah

The occurrence of ozone in the State of Utah should be considered on a regional basis. In general, higher concentrations of ozone are monitored in certain core areas where the majority of Utah’s population resides and where most major i ndustry is located. These core areas are also where high local and interstate vehi cular traffic predominate. In Utah, this core area is part of a geographical megalopolis region, better known as the Wasatch Front, extending from the Ogden area in Weber County on the north to the Provo ar ea in Utah County on the south, a distance of approximately 90 miles. This area is bounded on the east by the Wasatch Range and on the west by smaller north-south mountain ranges and the Great Basin. The Wasatch Range is actually an extension of the Northern Rocky Mountains which extends southward to Mount Nebo, in southern Utah County.

The yearly trend of NAAQS exceedances for ozone during the last twenty years shows a decline

in ozone. This trend has occurred at the same time that the federal standard has twice been tightened. During this same timeframe, c ounties along the Wasatch Front maintained the applicable standard, if only by the slightest of margins. Ambient ozone data collected in recent years indicates that the 2008 8-hr standard is r outinely exceeded at some monitors located within the state’s Wasatch Front core area monitoring ne twork, while other monitors located in more peripheral locations along the Wasa tch Front do not show violations . This reflects the State’s supposition that ozone generated in the major core area of the Wasatch Front actually moves throughout the area and is the probable cause for in creased ozone concentrations being recorded in some peripheral locations along the Wasatch Front. A further discussion of this phenomenon

can be found later in this document.

Data collected along the Wasatch Front also i ndicate that ozone is a seasonal problem, characterized by episodic elevated concentra tions during the summer months, usually June through August when temperatures routinely approach or exceed one hundred degrees Fahrenheit. These episodes generally occur duri ng periods of stagnant hi gh pressure associated with calm or very light wind conditions and a very stable atmosphere that acts to inhibit any

substantial vertical movement of the air. Under these conditions, ozone begins to form in areas where significant emissions of volatile organi c compounds (VOC) and oxides of nitrogen (NO x) , most prevalent in Salt Lake and Davis Counties, co mbine in the presence of strong solar heating. Ozone concentrations along the Wasatch Front ge nerally increase from mi d-to-late morning until late afternoon when solar intensity reaches its maximum. As the solar intensity begins to subside and evening rush hour traffic increases, data sugg ests that some of the ozone is scavenged by

NO

x and concentrations begin to decrease. Ozone concentrations generally remain at relatively low levels throughout the night and begin to incr ease the following morning after the rush hour traffic subsides. If high temperatures and light winds persist over a period of two to three days,

ozone can continue to form and accumulate al ong the Wasatch Front core area where it is5 contained vertically by nighttime subsidence and horizontally by the local topography as shown in Figure 1 below.

Data from both Utah Division of Air Quality (DAQ) and National Park Service (NPS) monitors

located in more rural and remote areas of the state show lower concentrations of ozone than those recorded along the Wasatc h Front. In many cases, these remote concentrations are substantially lower, and reflect a normal regiona l background level of ozone. At times, however, the regional background level of ozone may increas e due to ozone transpor t or as a result of wildfires during the summer season. A reasonabl e conclusion from available remote monitoring data is that the NAAQS is not ex ceeded outside of the urbanized or semi-urbanized counties that make up the Wasatch Front.

Ozone is formed by a chemical interaction of VOCs and NO

x in the presence of intense sunlight. Winds that occur during stagnant periods are genera lly of the diurnal mounta in-valley variety, or very light breezes that flow generally north-sou th along the Wasatch Front. On many occasions under these conditions, areas of higher ozone con centration have been transported by these local breezes. By tracking daily ozone concentrations at various locations along the Wasatch Front, it

has been noted that these concentrations increase a nd decrease in patterns that are consistent with local wind flows. For example, with a light southerly flow, concentrations that were originally higher in Utah or Salt Lake Coun ties tended to decrease while concentrations that were originally

lower in Weber and Box Elder Counties tended to increase. With a light northerly flow, the opposite effect was noted (i.e., co ncentrations at northern monito rs tended to decrease while

concentrations at southern monitors tended to in crease). The same phenomenon is true for light

Figure 1. Utah’s Wasatch Front extending from Utah County (Lower right) to Box Elder County (Upper left).6 diurnal southeast-northwest flows. This loca l mesoscale transport of ozone along the Wasatch Front also accounts for higher concentrations of ozone being monitored in peripheral areas adjacent to the Wasatch Front core areas where neither sources of VOC nor NO

x in amounts necessary to form ozone are found.

* Combined Statistical Area & Metropolitan Statistical Areas

Figure 2. Population Density of Utah Figure 3. Population Density w/CSA & MSA*

Ozone is generally considered an urban pollutant since the precursors needed to form it are present in most urban environments and are gene rally not present in rural environments. This serves to highlight the distinc tion between urban areas that ge nerally cause pollution and rural areas that may or may not contribute to the ozon e problem. Much of this phenomenon is also due

to the fact that the bu lk of Utah’s population is generally located within lowland valley areas along the Wasatch Front in which air is easily trapped either by meteor ological conditions or local topography. In other words, it is not enough to simply have an urban area with an urban mix of emissions; there must also be some barrier to dispersion which allows ozone concentrations to build up over a period of time and reach concentrations that eventually exceed the NAAQS.

The foregoing characterization of Utah’s ozone problem has shaped the State’s approach to making these area designations. The vast majority of Utah is sparsely p opulated (see Figure 2). Most of the monitoring data has been collected in the heavily populated urbanized areas of the state. This suggests that most of the areas recommende d for designation as either

“attainment/unclassifiable” will be either in th e rural areas of the state or in areas where precursors of ozone are not generated. Thos e areas recommended for the “nonattainment” designation will be urban areas where most of the sources of ozone precursors are found. However, our modeling domain will be much larger and will include all point sources within the modeling domain.7 Some distinctions have been made in the Environmental Protection Agency (EPA) guidance document regarding urban versus rural areas , relating to the presumptive boundaries of

nonattainment areas and to the level of assessment required in the case of a departure from the presumption. Urban areas are generally consid ered to be metropolitan areas surrounding core cities, whereas rural areas would be other areas no t included in or adjacent to urban areas. In

Utah there are several instances where both urba n and rural areas can be found within a single Metropolitan Statistical Areas (MSA). In many of these instances urban and rural areas have no

actual affect on each other. Reasons for this are significant separation due to topographical features and large areas of sparsely populated de sert or rangeland, and ve ry large MSAs. Figure 3 displays the population density shown in Figure 2 and also includes an overlay of the MSAs that comprise most of the counties of northern Utah. The Salt Lake-Ogden-Clearfield Combined Statistical Area (CSA) combines the Salt Lake City MSA, the Ogden-Clearfield MSA, the Brigham City Micropolitan Statistical Area (B ox Elder County), and the Heber Micropolitan Statistical Area (Wasatch County).

The most noticeable feature of these CSAs a nd MSAs is their size. The Salt Lake-OgdenClearfield CSA contains eight counties and cove rs 19,819 square miles (larger than nine US states). It extends east/west from the Nevada border to the southern Wyoming border, a distance of over 220 miles, and south from the Idaho border approximately 100 miles. The Provo/Orem

MSA contains two counties and covers an east west distance of 170 miles. Each of these MSAs includes densely populated areas, sparsely popu lated areas, and very large areas with no population at all. The sparse or unpopulated areas are due to ex tended desert in the west and

extreme mountainous terrain in the east. Th e largest concentration of both population and industry is found in the low valleys west of and adjacent to the Wasatch Front. Smaller concentrations of population are also found in some of the highe r valleys east of the Wasatch Range, but there are generally few or no major indus trial sources located in these areas. For the reasons cited above, and for additional reasons that wi ll be presented later, Utah feels it is more appropriate to designate nonattainment areas base d on the core urban area rather than MSA or

CSA boundaries.

The Cache County MSA located in northern Utah s hould be considered as an entirely separate entity as it is separated from the Wasatch Front by the northern extension of the Wasatch Front Range and is mainly influenced by separate meteorological and topographical factors. In addition, as we will see later in the monitori ng section of this document, Cache County is currently in attainment with the ozone standard and always has been. For these reasons Cache County should be treated independently and not be considered as part of the greater Wasatch Front metropolitan area.

The St. George MSA, comprised of Washington County, is located in the extreme southwest corner of Utah. Like Cache County to the north , Washington County is influenced by an entirely separate air shed. The National Park Service op erates an ozone monitor at the entrance to Zion National Park, and based on 2006-2008 data from that monitor, Washington County is currently attaining the ozone standard. Washington County air quality will be further di scussed later in this

report.

San Juan County, located in the southeast corner of Utah, is another area of the state that will also be discussed in this report.8 

## Regional Ozone

Over the past few decades it has become apparent that ground level ozone is not just a local city or urban area problem, but a regional problem. Se veral studies have found that ozone is present in most areas of the country, even where precursor s to ozone are not presen t. Transport (global and regional) of ozone has been found to be the mechanism that spreads or distributes the ozone from urban source areas, where precursors are read ily available, to more rural areas where no anthropogenic precursors are available. Some of the monitored ozone concentrations were attributable to regional backgr ound concentrations and, in some instances, portions of total

monitored ozone concentrations have been trace d to areas along the U.S. West Coast or even Asia. Additionally, smoke from wildfires, from both within the Intermountain Region and from as far away as California has been found to imp act local and regional ozone concentrations. The overall effect of this transport is a general concentra tion of ozone over a large regional area.

In 2001, a Harvard University study 1 was conducted to estimate background ozone

concentrations that would exist in the absence of anthropogenic emissions in the surface air over the United States using Global 3-D modeling. Th ey found that these con centrations generally varied from 25–45 ppb, with the highest conc entrations found over the Intermountain West region. A depiction of the mean summertime oz one variation across the United States is shown in Figure 4.

Figure 4. Mean summertime afternoon surface background ozone concentrations

__________________________ 1. “Estimating Background Ozone in Surface Ai r over the United States with Global 3-D Modeling of Tropospheric Chemistry,” Fiore, A.M. & Jacob, D.J., Harvard University Modeling Group, 2001.9 In addition, this study made the following conclusions:

• Stratospheric mixing generally accounts for 1- 5 ppb of the mean af ternoon surface ozone

concentration.

• Hemispheric transport from both Asian a nd European sources can range from 5-12 ppb and generally occurs at intermed iate ozone concentrations of 50-70 ppb.

• Regional ozone concentrations range from 8-30 ppb and are very site specific.

• Overall background ozone varies from 20-40 ppb. Higher concentrations of background ozone are generally found at higher el evations in the Intermountain West.

In 2003, a group of scientists used an aerosol an alysis model to study the transport of air masses

infused with biomass materials from Siberia to North America. 2 Transport of these air masses to North America was confirmed by aircraft and surface observations. The group’s findings include the following:

• Siberian biomass fires impacted both CO and ozone concentrations over a wide region of

western North America and contributed to excee dances of the ozone air quality standard

in the Pacific Northwest.

• Modeled calculation enhancements for ozone were 2-6 parts pe r billion (ppb) above normal expected concentrations and were cons istent with local observations of 5-9 ppb. The average enhancement during periods of low altitude intrusion resulted in observations 9-17 ppb above the normal expect ed concentration, depending on the site.

• Regression analysis estimated that the Sibe rian biomass fires contributed 14-15 percent

of the total ozone concentrations recorded during high ozone episodes.

In 2006, WESTAR conducted a study 3 to quantify the amount of ozone attributable to 1) natural background ozone, 2) transported anthropogenic ozone, and 3) lo cally generated anthropogenic ozone for certain large metropolitan areas in the we stern United States. The results for Salt Lake City showed that during periods with an average peak 8-hour ozone concentration of 91 ppb, 35 ppb were attributable to background ozone , 22 ppb were attributable to transported anthropogenic ozone, and 35 ppb were locally genera ted ozone. Similarly, during periods with an average peak 8-hour ozone concentration of 77 ppb, 35 ppb were attributable to background ozone, 20 ppb were attributable to transported an thropogenic ozone, and 22 ppb were attributable to locally generated ozone.

From these three studies one could conclude that:

• There is a regional background concentration of ozone pres ent throughout the entire Intermountain West;

• Ozone concentrations in the Intermountain West may be a regional concern;

___________________________ 2. “Long-range Transport of Siberian Biomass Burning Emissions and Impacts on Surface Ozone in Western North America,” Dan Ja ffe et.al, Geophysical Research Letters , Vol. 31, 2004

3. “Regional and Local Contributions to Peak Local Ozone Concentrations in Six Western Cities,” Sonoma Technology, Petaluma, Californi a, STI-906004-2970-FR, Final Report prepared for the Western States Air Resources Council, May 30, 200610 • Both transport of ozone and smoke from fires affects locally monitored ozone concentrations; and

• The actual amount that transport and wild fires contribute to the overall ozone concentration for a given location varies grea tly, and is difficult to quantify except in very specific instances.



## Regulatory Background

On March 12, 2008, the EPA promulgated revisi ons to the NAAQS for ground level ozone. It revised the 8-hour primary (health based) ozone standard to a level of 75 ppb. The previous standard, set in 1997, was 80 ppb. Additionally, the EPA specified the level of the primary standard to three decimal places, thereby eliminating the ro unding convention that was present in the previous standard. The EPA also revised the 8-hour secondary (welfare based) ozone st andard to be identical to the revised primary standard.

Section 107(d) of the CAA establ ishes that it is incumbent on each state to recommend initial designations for all areas within its respective geographic boundary following promulgation of a new or revised NAAQS. States are required to submit these recommendations to EPA, based on the most current three year data set, not later than one year after the promulgation of the new or revised

standard.

Areas should be designated as atta inment, nonattainment, or unclassifia ble. The Act allows that areas may be designated as:

(a) attainment, for any area other than an area identified in clause (b) that meets the national primary or secondary ambient air quality standard for the pollutant; or

(b) nonattainment, for any area that does not meet (or that contributes to ambient air quality in a nearby area that does not meet) the nati onal primary or s econdary ambient air quality standard for the pollutant; or

(c) unclassifiable, for an y area that cannot be classified on the basis of available information as meeting or not meeting the national primary or secondary ambient ai r quality standard for the pollutant.

EPA must finalize the area designations as expediti ously as practicable, but not later than two years following the effective date of the revised NAAQS. In the event that EPA intends to promulgate a designation that deviates from th e State’s recommendation, it must no tify the State at least 120 days prior to promulgating the modified designation to pr ovide the State an opport unity to comment. The EPA’s designation of areas for the 8-hour ozone NAAQS will be based on the most current three consecutive years of air quality data at the time of the final designation. 4

____________________ 4. For the 8-hour ozone NAAQS, it is the three consecutive years of data obtained in accordance with 40 CFR part 50, Appendix I; data used wi ll be quality-assured and meet 40 CFR part 58 requirements (e.g., for monitor siting). Recommende d designations should generally be made based on 2006-2008 monitored air quality data a nd final designations on 2007-2009 data.11 

## Applicable Guidance

On December 4, 2008, EPA issued a guidance memorandum 5 to assist States and Tribes in making their recommendations with respect to ozone. The memorandum recommended that Core Based Statistical Areas (CBSA) or Combined St atistical Areas (CSA) serve as the presumptive boundary for evaluating the geographic boundaries of an ozone nonattainment area. This recommendation reflected a generic assumption that violations of the oz one NAAQS in urban areas may be attributed to contributions from s ources distributed throughout the MSA based upon population density, traffic & commuting patterns , commercial development, and area growth.

Current CSAs and MSAs in the State of Utah and th e counties that are include d in these areas are as

follows:

• Logan MSA Cache County, Utah and Franklin County, Idaho

• Salt Lake-Ogden-Clearfield CSA Box Elder County Davis County Morgan County Salt Lake County Summit County Tooele County Wasatch County Weber County

• Provo Orem MSA Juab County Utah County

• St. George MSA Washington County

Section 107(d) of the CAA addresses the determin ation of whether an area is to be designated nonattainment. With respect to the 8-hour oz one NAAQS, all areas are to be designated nonattainment if they do not meet the standard or contribute to ambient air quality in a nearby area that does not meet the standard. The guidance me morandum further stated that EPA would consider requests for urban nonattainment area definitions that deviate from the MSA or C/MSA boundary definitions on a case-by-case basis, considering the following factors:

1. Air Quality monitoring data

2. Emissions data 3. Population density and degree of urba nization including commercial development significantly different from surrounding areas 4. Traffic and commuting patterns 5 Growth rates and patterns 6. Meteorology (weather /transport patterns) 7. Geography/Topography (mountain range s or other air basin boundaries)

8. Jurisdictional boundaries (existing ozone areas)

9. Level of control of emission sources

________________________________________ 5. “Area Designations for the 2008 Revised Ozone National Ambient Air Quality Standards,” Memorandum from Robert Meyers dated December 4, 200812 

## Document Organization

Utah’s recommendations concerning area design ations for the revised National Ambient Air Quality Standard for ozone will be presented at the end of this document. Generally speaking, rural areas recommended for designation as “attain ment” or “unclassifiable” will be described by county. Exceptions to this approach will incl ude Tribal Lands and portions of counties that

contain nonattainment areas.

Since the description of Utah’s nonattainment areas located in urban areas will deviate somewhat from the presumptions outlined in the EPA guidance memoranda, the recommendations will need to be supported by considering the nine fa ctors identified in that guidance. The next portion of this document addr esses those nine factors.

It should also be kept in mind that the reco mmendations presented herein represent Utah’s preliminary assessment of the spatial distribution of its ozone problem. As actual work proceeds on the implementation plan necessary to address the problem, Utah reserves the right to

recommend modifications to the nonattainment area boundaries. Utah will include emission

sources outside of the no nattainment area in the control strategi es as has been done in prior state implementation plans (SIP) that have been approv ed by the EPA, and were successful in meeting the NAAQS.



## Discussion of EPA Guidance Factors

Factor 1: Air Quality Monitoring Data

In general, Utah monitoring data are collected from Federal Reference Method (FRM) or Federal Equivalent Method (FEM) monitors that are site d and operated in accordance with 40 CFR Part

58. The monitors are sited to address various monitoring objectives, including the assessment of air quality in regions where people live and work; the identification of highly impacted areas; and identification of background concentrations in areas of low impact. In addition, DAQ occasionally sites survey monitors for special purposes in areas where high ambient concentrations might be expected. As discusse d earlier, ozone may be characterized as an “urban” pollutant; therefore, in most cases, thes e monitors have been si ted in urban areas. The spatial distribution of these monitors may be seen in Figure 5. The colors of the dots used to approximate the monitor locations show whethe r the three-year aver age (2006-2008) of the 4 th
highest ozone concentration at that monitor is at or below the current 0.075 ppm NAAQS ( green ) or above the NAAQS ( red ). The Santa Clara monitor was placed in operation in July 2008 and does not yet have enough data history to be used for an official attainment

determination.13 Figure 5. Utah’s Air Monitoring Network

Attainment of the primary NAAQS for ozone is determined by the 4 th highest concentration

recorded at each monitor. Attainment of the oz one standard occurs when the most recent threeyear average of the 4 th highest concentration recorded at each monitor is less than or equal to 0.075 ppm. Conversely, nonattainment occurs when the most recent three-year average of the 4 th
highest concentration recorded at each monitor is greater than 0. 075 ppm. EPA recommends that14 States identify violating areas usi ng the most recent three-year set of air quality data. In Utah, this encompasses the years from 2006 through 2008. Data affected by exceptional events may be excluded from use in identifying a violation if it meets the exclusion criteria. The three-year average data cited in this factor represents both flagged and unflagged data. Since the final designation determination by EPA is not required until March of 2010, data collected in 2009 may be considered as the designation process proceeds.

Table 1 shows the 4 th highest ozone concentration as well as the three-year average of the 4 th
highest ozone concentrations (des ign value) recorded at each of the monitoring stations in the DAQ network. These are the official monitors disc ussed previously in this section. An obvious

conclusion from Table 1 is that there are seve ral areas of nonattainme nt to the new 0.075 ppm standard within the monitoring network. Thes e areas are located along the Wasatch Front in Weber, Davis and Salt Lake counties and are highlighted in red in Table 1.

Table 1. Ozone Concentrations from official Utah DAQ Monitors

1. Concentrations and counties indicated by red indicate violations of the current NAAQS. 2. The Washington Terrace, West Valley and Herriman monitors we re shut down in 2008 to make more efficient use of our resources

. 3. The Ogden monitor became operational on June 13, 2008. 4. The Santa Clara monitor became operational on July 10, 2008.

5. The left column indicates data with flagged days included. The right column i ndicates data with fl agged days excluded.

6. All monitors in the Provo-Orem MSA are attainment for ozone.

Monitored concentrations in Utah County (North Provo, Highland and Spanish Fork), Box Elder County (Brigham City), Cache County (Logan) , Tooele County (Tooele), and Washington County (Santa Clara) currently show attainment of the NAAQS. Monitors located in Box Elder,

Tooele and Utah counties show that concentr ations there are very close to exceeding the standard, and these areas will be discussed throughout this report.

The Logan monitor in Cache County and the Santa Clara monitor in Washington County show

that the monitored concentrations in these ar eas are well below the NAAQ S; therefore Cache and Monitoring Sites 4 th Highest O 3 Concentration Design Values 3-year Average of

the 4 th Highest O 3

Concentration 1

Name County 2006 2007 2008 5 2006-2008 5

Salt Lake-Ogden-Clearfield CSA
Brigham City Box Elder 0.078 0. 077 0.072/0.072 0.075/0.075

Bountiful Davis 0.082 0.082 0.078/0.077 0.080/0.080 Washington Terr 2 Weber 0.083 0.080 No data n/a Ogden 3 Weber no data no data 0.075 n/a

Harrisville Weber 0.083 0.082 0.076/0.073 0.080/0.079

Cottonwood Salt Lake 0.084 0.082 0.081/0.077 0.082/0.081

Beach Salt Lake 0.082 0.082 0.074/0.073 0.079/0.079

Hawthorne Salt Lake 0.082 0.079 0.076/0.072 0.079/0.077 West Valley 2 Salt Lake 0.080 0.080 no data n/a

Herriman 2 Salt Lake 0.082 0.079 no data n/a

Tooele Tooele 0.079 0.076 0.071/0.070 0.075/0.075

Provo-Orem MSA 6

North Provo Utah 0.074 0.075 0.075/0.073 0.074/0.074 Highland Utah 0.077 0.078 0.072/0.071 0.075/0.075 Spanish Fork Utah 0.079 0.077 0.071/0.070 0.075 / 0.075

Non-Wasatch Front Counties
Logan Cache 0.073 0.074 0.067 0.071

Santa Clara 4 Washington no data no data 0.063 n/a15 Washington counties will not be considered a ny further as potential areas for nonattainment designations.

EPA has chosen to use NPS CASTNet monitori ng data in their preliminary nonattainment decision making process. Data from national pa rks and monuments located within or in close proximity to the State of Utah are included in Table 2 to get a reasonable indication of ozone

concentrations in remote areas of the State and Region. Again, it should be kept in mind that CASTNet monitors do not meet the same quality a ssurance standards as those maintained by the State of Utah and, as such, should be considered unofficial indicators.

Table 2. Ozone Concentrations from Nationa l Park Service (CASTNet) Monitors and one monitor located in “Indian Country.”

1. The Washakie monitor is located near Portage, Box Elder Count y, Utah, in “Indian Country”. This monitor is under the contro l of

the Northwestern Band of the Shoshone Nation. It is a Federal Reference Method monitoring site.

Both DAQ and NPS monitors located in remote areas in and around the St ate of Utah indicate

that rural areas of Utah are not violating the 0.075 ppm NAAQS.



### Factor 2: Emission Data

Table 3 shows precursor component emissions fo r ozone in the counties under consideration for nonattainment designations. In th e case of VOCs, biogenic emissions have been eliminated from consideration to get a clearer understanding of county industrial emissions. In addition, nonozone season emissions have also been deleted fo r each county to present a better picture of the actual ozone season precursors available during the summer ozone season.

Table 3. Ozone Precursor Emissi ons (Utah 2005 Emission Inventory)

Note: Non ozone season emissions including agricultural burning and harvesting, and a ll residential and wood combustion categor ies have been subtracted from total emissions to give a better picture of both VOC and NOx emissions during the ozone season. These emission s do not take place during the ozone season. Monitoring Sites 4 th Highest O 3 Concentration 3-year Average of the 4 th
Highest O 3 Concentration

Name Location 2006 2007 2008 2006-2008

Washakie Res 1 Northern UT 0.076 0.078 0.073 0.075

Dinosaur NM Northeast UT no data 0.063 0.067 n/a Canyonlands NP Southeast UT 0.070 0.072 0.071 0.071

Mesa Verde NP Southwest CO 0.074 0.070 0.069 0.071

Zion NP Southwest UT 0.075 0.071 0.073 0.073 Grand Canyon NP Northwest AZ 0.070 0.069 0.071 0.070

Great Basin NP East Central NV 0.072 0.075 0.071 0.072

Wasatch Front

MSA

Counties VOC Emissions Not counting

Biogenics (tpy) Ozone Season

VOC

Emissions (tpy) NO

x Emissions (tpy) Ozone Season

NO

x Emissions (tpy)

Box Elder 7,382 2,228 5,617 1,326

Davis 11,635 6,994 10,741 2,627 Morgan 613 276 3,170 789

Salt Lake 37,121 24,069 38,106 9,779

Summit 2,198 1,102 4,162 1,035

Tooele 5,402 2,022 5,494 1,372

Weber 8,346 5,332 6,880 1,663

Wasatch 1,041 557 1,227 305

Utah 17,315 10,891 13,591 3,473

Juab 1,744 477 4,756 1,17116 Salt Lake, Davis and Weber Counties collectiv ely produce 67.4 % of the VOCs and 59.8 % of

the NO

x that is monitored along the Wasatch Front. Utah and Juab Counties collectively have

more moderate VOC and NO

x emissions and account for 21.1 % of the VOC and 19.7 % of the

NO

x . Box Elder and Tooele Counties, which are lo cated further from the central core of the Wasatch Front, have much lower VOC and NO

x emissions, and together account for only 7.9 %

of the VOC and 11.5 % of the NO

x respectively. Morgan, Summit and Wasatch Counties, even though they are included in the Salt Lake-Ogden- Clearfield CSA, together only account for

3.6 % of the VOC and 9.0 % of the NO

x emissions during the ozone season. These percentages are depicted in the following pie charts.

Percentage of VOC by County

21.1 7.9 3.6

67.4 Salt Lake, Davis & Weber Co's

Utah & Juab Co's

Box Elder & Tooele Co's

M organ, Summit & Wasatch Co's Percentage of NOx by County

59.8 19.7

11.5 9.0 Salt Lake, Davis & Weber Co's

Utah & Juab Co's

Box Elder & Tooele Co's

M organ, Summit & Wasatch Co's

Figure 6. Percentage of VOC and NOx pr oduced along the Wasatch Front (by Counties)

In the case of both Box Elder and Tooele counties, the majority of VOC and NO

x emissions are generated from sources that are located in the ex treme eastern portions of these two counties; the western areas of both counties are very sparse ly inhabited desert areas. Any VOC or NO

x produced in these west desert areas would come from sources located far from populated core areas (reference Figures 2 & 3).

In Weber County, the majority of both VOC and NO

x emissions are from sources located only in the western portion of the county. Western Webe r County is part of the core nonattainment area

of the Northern Wasatch Front because it is the home to several industrial sources that produce ozone precursors. The eastern portion of Weber Count y and all of Morgan County are located east of the Wasatch Range and, with the exception of the Devil’s Slide cement plant located in extreme eastern Morgan County, have only minor emissions of both VOC and NO

x . The Wasatch Range prevents emissions from eas tern Weber County and Morgan County from impacting in the core nonattainment area (see table 8).

Summit County, located east of Salt Lake City, extends over 100 miles east from the Wasatch Range to the southern border of Wyoming. W ith the exception of one moderate point source,

emissions of VOC and NO

x in Summit County are very low.

Juab County which is part of the Provo/Orem MSA extends from the Nevada border on the west to Mount Nebo, the southern most extension of th e Wasatch Range, on the east. Like Tooele and Box Elder counties, it has little or no population we st of the I-15 corridor which is located in the17 extreme eastern end of the county. The only si gnificant industrial sour ce of emissions in the county is the Leamington Cement Plant located in a mountainous area 35 miles west of Nephi.

Cache County has relatively low VOC and NO

x emissions during the ozone season. Washington County, located in the extreme southwest corner of Utah, has low to moderate VOC and NO

x emissions.

In Section IX, Part D of the Utah State Impl ementation Plan which was submitted to EPA in January 2007, DAQ demonstrated that both VOC and NO

x emissions along the Wasatch Front are projected to continue decreasing thorough at least 2014. This is demonstrated in the following VOC and NO

x projection graphs (Figures 7 and 8) taken from the SIP:

VOC Projections for Salt Lake & Davis Counties (tons/day)

Biogenic Source

Point Source Area Source Mobile On-Road Mobile Non-Road

0 50 100 150 200 250 300 350

2002 2005 2008 2011 2014VOC (tons/day) Attainment = [308.06]

Figure 7. VOC Projections through 2014

NOx Projections for Salt Lake & Davis Counties (tons/day)

Point Source Area Source Mobile On-Road Mobile Non-Road

0 50 100 150 200 250

2002 2005 2008 2011 2014NOx (tons/day) Attainment = 233.39

Figure 8. NOx Projections through 201418 Based on the relative emission leve ls presented in Table 3 and Fi gure 6, the majority of ozone precursor emissions along the Wasatch Front come from sources in the we stern portio n of Weber County, Davis County and Salt Lake County. Utah County does produce a moderate amount of precursor emissions in the southern part of th e county, but their effects are mainly felt only within Utah County due to the topography of Utah Valley. The remaining Wasatch Front counties, Box Elder, Juab, Morgan, Summit and Wasatch, have low or no impact on

concentrations in the core area.



### Factor 3: Population Density

Urbanization refers to a high con centration of population. It refers to populations that are directly attributable to or located within cities or large metropolitan areas. It is the opposite of rural, which refers to country areas with rela tively low populations spread over larger areas. Directly associated with urbanization is the mi x of human related emissions that can lead to

elevated levels of ozone. EPA has made urbanized areas the focus of its guidance concerning violations of the ozone NAAQS, largely because precursor emission sources associated with

both human and industrial activities occur with much greater frequency in these more populous areas. Table 4 below shows the population densit y in counties that are potential candidates for nonattainment areas. Population data from the most recent 2000 census has been plotted (persons/square kilo meter) in Figure 9 for a large domain area extending from the Idaho border

to central Utah. This is the area that includes the greater Wasatch Front, where approximately 85 % of Utah’s population resides.

Table 4. Population Densities in Counties be ing considered as potential candidates for Nonattainjment Areas

Note: Data obtained from Stat e of Utah county census data

When considering emissions of the precursors of ozone, population can be tied to emissions labeled as point source, area source, and mobile source emissions. It is fairly common for large point source industries to be co-located with in or near large urban areas for many reasons, including access to human res ources, educational institutions , transportation, distribution facilities, etc. Emissions from many of the ar ea source categories are ca lculated on a per-capita County Initial State

Recommendation

(Based on monitoring data) 2005 Population 2005 Population Density

( Population per square Km)

Salt Lake-Ogden-Clearfield CSA
Box Elder Attainment 45,142 18

Davis Nonattainment 276,374 1,098 Morgan Attainment 8,516 36

Salt Lake Nonattainment 970,748 3,082
Summit Attainment 36,283 41
Tooele Attainment 51,835 18
Wasatch Attainment 19,999 34

Weber Nonattainment 212,707 829

Provo-Orem MSA
Utah Attainment 453,977 546
Juab Attainment 8,974 5

Non-Wasatch Front MSA Counties

Cache Attainment 103564 202 Washington Attainment 117,385 12419 basis. In developing commonly used emission f actors, it is recognized that population is a good surrogate for the number of minor industries that operate within any typical urban area. Mobile

source emissions are also a function of the numbe r of people who operate motor vehicles within a given area. This suggests that the bulk of the point source, area s ource, and mobile source emissions originate within regions with higher po pulation densities which are shown in Figure 9.

The risk of human exposure to unhealthy concentr ations of ozone is gr eatest within densely populated areas. The distribution of the monito ring network attempts to address this by providing ozone monitoring in and around highly populated areas. This is illustrated by comparing Figures 5 and 9. As shown in Fi gure 9 the eastward exte nsion of the population density essentially ends at the west ern border of the Wasatch Range.

Figure 9. Population Density (W asatch Front) with Counties20 There are several populati on centers located in th e upper valleys east of the Wasatch Front, but these are mostly suburban farming communities with little or no industrial base. These areas will

be addressed in the discussion of Factor 8 a nd in the “Additional Areas ” section following the

discussion of Factor 9.

Thus far, the discussion has centered on north ern Utah, which includes the Greater Wasatch

Front. The Greater Wasatch Front is Utah’s most urbanized area, and is the only area to violate any of the prior NAAQS for ozone. Figures 2 and 3 show another area of the state, which may warrant some consideration on the basis of popul ation and to some degree urbanization. The populous region in the southwest co rner of the State is the city of St. George which has a population of sixty-five thousand (there are a bout one-hundred twenty thousand people in the greater St. George area). Consideration of th is region would be in the context of its own nonattainment area, rather than as one which contributes to a viol ation elsewhere. As some of the remaining factors to be considered are discussed, Utah’s recommendation concerning Washington County will be discussed further.



### Factor 4. Traffic and Commuting Patterns

Data presented in Table 5 displays vehicle miles traveled, the number of commuters driving, in county and out-of-county, and the percentage of commuters that commute to other counties to work, in areas being considered for nonattainment designations.

Salt Lake County is the destination for the la rgest number of out-of-county commuters from Davis, Tooele and Utah counties. Conversely, Davis and Utah counties are the destinations for the largest number of out-of-county commuters from Salt Lake County. Most out-of-county commuters from Box Elder County commute to Weber County for work and most out-of-county commuters from Morgan and Weber County commute to Davis County for work. Similarly most out-of-county commuters from Tooele, Su mmit and Wasatch counties commute to Salt

Table 5. Traffic and Commuting Patterns (2005 Data)

Note: Data obtained from www.epa.gov/ttn/naaqs/pm /pm25_2006_techinfo.html . (VMT by county, County-to County worker flows) County Initial State

Recommendation

(Based on Monitoring Data) 2005 VMT

(Millions/Year) Commuting

Within County

(number) Commuting

to other

Counties

(number) Commuting

to other

Counties

(% of total) Salt Lake-Ogden-Clearfield CSA

Box Elder Attainment 782.7 13,570 4,330 24.2

Davis Nonattainment 3,352.0 61,208 50,567 45.2 Morgan Attainment 109.2 1,217 1,930 61.3

Salt Lake Nonattainment 7,511.9 411,283 24,189 5.6
Summit Attainment 551.4 10,486 4,912 31.9
Tooele Attainment 804.2 9,784 7,655 43.8
Wasatch Attainment 226.8 3,857 2,968 43.5

Weber Nonattainment 1,994.6 64,671 25,975 28.7

Provo-Orem MSA

Utah Attainment 4,214.8 140,843 21,050 13.0
Juab Attainment 342.9 2,011 1,332 39.8

Non-Wastach Front MSA Counties

Cache Attainment 935.9 39,235 3,987 9.2 Washington Attainment 1,112.8 32,708 977 2.921 Lake County to work. Most out-of-county commuters from Juab County work in Utah County. Essentially most of the out-of-county commuters tr avel into the core metropolitan areas to work

and return commute to their home counties after work.

This is evidenced by the fact th at several of the counties that are candidates for nonattainment show a higher percentage of commuters traveling to Salt Lake County than those traveling from Salt Lake County to other counties.

In addition, from table 5 it is obvious that commuting trips from counties that make up the periphery of the Wasatch Front core area (Box Elder, Morgan, Summit, Tooele, and Wasatch) are insignificant when compared to the number of in-county trips within the core counties (Davis, Salt Lake, and Weber).

Hill Air Force Base, located in northern Davis County, is one of the largest employers in the state. It employs people from all counties located al ong the Wasatch Front. On the other hand, the vast majority of employees at Brigham Y oung University, another large employer in the state, commute mainly from within Utah County.

Mobile sources have always been a signifi cant source category in the attribution of NO

x which is one of the precursor gasses needed to form oz one. Without current federal requirements that mandate improvements in NO

x emissions from cars and light-dut y trucks, it is unlikely that the previous (0.08 ppm) ozone standard could have been attained along the Wasatch Front. Mobile sources currently account for approximately 65% of the NO

x within the areas likely to be designated nonattainment for ozone. The two largest Metropolitan Pl anning Organizations (MPOs) for the Wasatch Front have provided detailed emissions data for use in modeling exercises. Most significant is the information concerning vehicle miles traveled (VMT). This information has been geographically compiled on the basis of travel along what are called roadway “links” for a study area surrounding the Wasa tch Front. These links describe discrete portions of the transportation network that are categorized as either freeways or arterial roadways. When this information is plotted on a map (see Figure 10), the result is a very good approximation of Utah’s urban population distribution.22 Figure 10. Population Density and Area Roadways



### Factor 5. Growth Rates and Patterns

This factor looks at actual population and VM T growth from 2000 to 2005 as well as forecasted population and VMT growth to 2020. Generally, counties with rapid or higher than average population and VMT growth are found to be integral parts of an urban core area. Tables 6 and 7 show the most recent population and VMT projecti ons for counties that could be considered for a nonattainment designation. The tables are based on actual 2000 and 2005 census and VMT data with projections to 2010 and 2020. Table 6 show s that both Salt Lake and Utah counties are expected to have the highest population growth of all counties located along the Wasatch Front23 over the next twelve years. Utah County’s anticipated population growth rate from 2010-2020 is, in fact, one and one-half times that of Salt La ke County’s. This expected growth correlates quite well with the current location of Utah’s ma jor industrial and educational infrastructure.

Davis County, which borders Salt Lake County on th e north, is expected to have the next highest population growth with Weber County close behind. These four counties, which make up the core emissions area of the Wasatch Front, will account for approximately 82.5 percent of the Wasatch Front population growth by 2020. Tooele, Box Elder and Juab counties, located on the northern and western periphery of the major core areas, and Morgan, Summit and Wasatch counties, located east of the Wasatch Range, will also experience significant increases in their population numbers, but will only account for 17.5 percent of the core area population growth by

2020.

When considering Metropolitan Planning Orga nizations (MPOs), The Wasatch Front MPO, consisting of Salt Lake, Davis, Weber, Morgan a nd Tooele counties, is expected to have a

Table 6. Projected Population Growth (2000-2020)

Note: Data obtained from www.governor.utah.gov/dea/projections.html (Governor’s Office of Pl anning and Budget – GOPB).

population increase of over 300,000 between 2010 and 2020. The Mountainland Association of Governments (MAG), consisting of Utah, Summit a nd Wasatch counties, is expected to have a population growth of over 165,000 during the same tim e period. These increases translate to an 18.1 percent increase for the Wasatch Front MPO and a 27.8 percent increase for the

Mountainland MPO.

As we look at Table 7 below, it should be not ed that there are many similarities between population growth and VMT growth. With the ex ception of Box Elder County that experienced an actual decrease in VMT between 2000 and 2005, a ll counties in the area are projected to have significant population and VM T growth through 2020. Area 2000

Actual 2005

Actual Actual

Increase

2000-2005 2010

Estimated Estimated

Increase

2005-2010 2020

Estimated Estimated

Increase

2010-2020
Salt Lake-Ogden-Clearfield CSACounties

Box Elder 42,860 45,142 2,282 49,254 4,112 61,675 12,421
Davis 240,204 276,374 36,170 304,502 28,128 352,320 47,718 Morgan 7,181 8,516 1,335 10,589 2,073 16,756 6,167
Salt Lake 902,777 970,748 67,971 1,053,258 85,510 1,230,817 177,559
Summit 30,048 36,417 6,369 44,511 8,094 65,001 20,490
Tooele 41,549 51,835 10,293 67,150 15,315 95,696 28,546
Wasatch 15,433 20,138 4,705 25,516 5,378 37,082 11,566
Weber 197,541 212,707 15,133 230,145 17,438 271,339 41,194

Provo-Orem MSA

Juab 8,310 8,974 664 10,519 1,545 14,158 3,639
Utah 371,894 453,977 82,083 527,502 73,525 651,319 123,817

Non-Wasatch Front MSA Counties

Cache 91,897 102,477 10,580 114,304 11,827 147,776 33,472 Washington 91,104 125,010 33,906 162,544 37,534 251,896 99,352

Areas/MPO’s
Bear River 136,712 149,705 12,993 165,705 16,000 211,898 46,193
Wasatch Front 1,389,252 1,520, 189 130,973 1,665,238 145,049 1,966,372 301,134
Mountainland 417,375 510,532 93,157 597,529 86,997 763,402 165,873
Southwest 135,969 176,202 40,233 223,846 47,644 335,025 111,179

State of Utah 2,246,553 2,528,926 282,373 2,833,337 304,411 3,486,218 652,88124 Table 7. Projected Annual VMT Growth in Greater Wasatch Front Area (Millions)

Note: Data obtained from Wasatch Front Regional Council, Mountainla nd Association of Governments, Utah Dept of Transportation, and

Governors Office for Pl anning and Budget-GOPB.

Similar to Table 6 for population growth, Table 7 shows that, over the next twelve years, Salt Lake and Utah counties are expected to have the highest VMT growth of all the counties along

the Wasatch Front area. From the data we can calculate that, from 2010-2020, Weber, Davis, Salt Lake, and Utah County’s expected VMT grow th rates will be 33.8 %, 22.4 %, 22.8 % and 26.1 % respectively. Once again, and with numbers similar to t hose for population growth, these

four counties will account for 74 percent of the areas VMT growth by the year 2020.



### Factor 6. Meteorology

The quality of Utah’s air is generally good, with the exception of certain episodic periods during which the air quality is degraded. In the case of ozone, these episodes are most always associated with a semi-permanent high pressu re ridge that become s stationary over the intermountain region, clear skies, intense direct su nlight, and stagnant air with very light surface wind movement. When these meteorological cond itions occur simultaneously, they can aid in

the formation of ozone while at the same time providing minimal vertical mixing.

Under these stagnant conditions, emissions produc ed within the populated urban valley areas do not disperse and are maintained in the bowl-shaped valleys. As a result, increased concentrations of ozone are able to build up over a period of se veral days and to actually meander or oscillate north/south along the Wasatch Front. Under proper conditions, air origina ting in a southern area could move northward along the Wasatch Front, a nd conversely, air origin ating in a northern area could travel southward along the same path.

Actual day-to-day transport of the ozone along the Wasatch Front is mainly influenced by the

diurnal effects of the local mount ain/valley airflow caused by the Gr eat Salt Lake and Utah Lake on the west and the very prominent Wasatch Range on the east (see table 8). As mentioned above, areas of high ozone concentration have been sh own to oscillate both north and south along the Wasatch Front. They also move east and west from areas adjacent to the Wasatch Front to areas over the Great Salt Lake in Weber, Davis and Salt Lake Counties and over Utah Lake in Utah County. In

County 2000

Actual 2005

Actual Actual

VMT
Increase

2000-2005 2010

Estimated Estimated

VMT
Increase

2005-2010 2020

Estimated Estimated

VMT
Increase

2010-2020
Salt Lake-Ogden-Clearfield CSA Box Elder 2.96 2.92 (.040) 3.55 0.63 4.85 1.30

Davis 5.72 6.21 0.49 7.19 0.98 8.80 1.61 Morgan 0.38 0.38 0 0.46 0.08 0.63 0.17

Salt Lake 21.63 23.36 1.73 27.27 3.91 33.49 6.22 Summit 2.12 2.03 (0.09) 2.46 0.43 3.37 0.91

Tooele 1.82 2.37 0.55 2.88 0.51 3.95 1.07

Wasatch .64 .82 0.18 1.00 0.18 1.37 0.37

Weber 3.98 4.31 0.33 4.56 0.25 6.10 1.54

Provo-Orem MSA

Juab 1.04 1.17 0.13 1.42 0.25 1.95 0.53

Utah 8.62 10.01 1.39 11.48 1.47 14.48 3.0025 all cases the general westward movement occurs during the late evening and nighttime hours and the reverse eastward movement occurs during the day light hours. This is a typical mountain valley

flow.

In the case of Box Elder County in the north and Tooele County in the sout h, it is possible that the diurnal air flow moves air containing “oz one clouds” into and out of these counties on a routine basis and could be responsible for some of the higher concentrations monitored in these counties. In essence, both Box Elder and Tooe le Counties are not significant emitters of ozone or its precursors, but receptors. The same could be said for all c ounties east of the Wasatch range and for Juab County south of the Wasatch Front.



### Factor 7. Geography/Topography

The Wasatch Range, extending from near the Idaho bor der to Mt. Nebo, at the southern tip of the Northern Rocky Mountains, is a formidable obst acle to surface air mass movement toward the

east. A satellite view of the region is provided in Figure 11. Probably the most prominent feature in this figure is the Wasatch Front whic h functions as the eastern boundary of the Great Basin. Here, the Wasatch Mountains rise abrup tly to elevations of between 4,000 to 6,000 feet above the valley floor and help to define the Wasatch Front urban areas from Brigham City on the north to the numerous metropolitan areas in Utah County on the south. These valleys are bound on the West by the Great Salt Lake in the north and the Oquirrh Mountains, which also rise 4,000 to 5,000 feet above the va lley floor, in the south. In an area of flat terrain one would expect an air mass to gradually be transported in a direction c onsistent with the prevailing air flow. Conversely, in an area of mountainous te rrain, as is the case of the valleys along the Wasatch Front, one would expect the terrain to define the air mass boundaries and movement. With prevailing winds from the west through th e north, the high terrain with its bowl shaped valleys that open to the north and west routin ely functions to block any eastward horizontal movement of a stagnant air mass. In effect, the local topography actually contains stagnant air masses within these valleys.

To help appreciate the significance of the barrie r that the Wasatch Front Range poses to the eastward horizontal movement of air, Table 8 give s the average valley floor elevation at several sites along the Wasatch Front and the average elevation of the Wasatch Mountain Range directly east of the valley floor location.26 Figure 11. Wasatch Front Topography27 Table 8. Elevations of Valley Floor a nd Adjacent Mountains along the Wasatch Front

As discussed in the meteorology section, it has b een found in several studie s that concentrations of ozone trapped in large mountain valleys alon g the Wasatch Front, such as the Salt Lake Valley and Utah Valley, actually move horizontally within or in and out of the valleys with the diurnal mountain-valley flow. In the Salt Lake Valley, for instance, the nighttime flow generally moves the air to the northwest over the eastern po rtion of the Great Salt Lake while the daytime

flow moves the same air back s outheastward into the valley wher e it is contained by the Wasatch Range. In Utah Valley the air is more contai ned and generally moves westward over Utah Lake in the evening and eastward again during the day. In some instances, however, the air mass in either the Salt Lake Valley or Utah Valley has moved north or south to affect the other valley. In the region north of Salt Lake City air masses have a tendency to move both north and south along the Wasatch Front as well as east and west with the diurnal flow.

Not only does the topography of these regions act as a barrier to air movement during conditions which lead to elevated concentrations of ozone, it also acts as the primar y factor in determining where the population is located. In other words, the lower valle ys which contain the air during periods of summertime stagnation are also the areas within which most people choose to live. These populations produce the emissions which lead to ozone formation under the conditions

described above.

Both Figure 11 and Table 8 show that much of th e eastern area of the Wasatch Front counties is at a much higher elevation than the adjacent west ern valleys, and would therefore not experience the high concentrations of ozone produced in th ese urban valleys. These regions would have neither the sources of emissions necessary to produce high ozone concentrations, nor a pathway for incurring impact from upwind urban areas.

Thus, the topography, when considered alongside the predominant meteorology, would suggest that these areas of high mountai nous terrain not be in cluded in a descript ion of nonattainment area(s). Box Elder County Valley Elevation Mountain Elevation Elevation difference

Tremonton 4320 ft 8979 ft 4659 ft Honeyville 4291 ft 9330 ft 5039 ft Brigham City 4363 ft 8035 ft 3672 ft Weber County

Harrisville 4390 ft 9196 ft 4786 ft Ogden 4350 ft 9238 ft 4888 ft Davis County Kaysville 4363 ft 9297 ft 4934 ft

Bountiful 4283 ft 8819 ft 4536 ft Salt Lake County Salt Lake City 4363 ft 9107 ft 4744 ft

Cottonwood 4455 ft 9176 ft 4721 ft Utah County Highland 4950 ft 10,698 ft 5748 ft
Provo 4691 ft 10,630 ft 5939 ft Spanish Fork 4590 ft 9430 ft 4840 ft Average 4451 ft 9328 ft 4876 ft28 

### Factor 8. Jurisdictional Boundaries

In this factor we will look at jurisdictional boundaries and regional government organizations that have law-making authority for these areas. When considering these organizations, and their areas of jurisdiction, it will become clear that the implementation of most of the required control strategies necessary to combat precursors to ozone could be best implemented on a county basis.

Box Elder County

Box Elder is a very large and mostly rural count y located in the northwe st corner of Utah. Ninety-nine plus percent of the population is concentrated in the extreme eastern portion of the county along the northern Wasatch Front and clos ely associated with the I-15 and I-84 freeways

that extend north into Idaho. The western three-quarters of the county, extending to the Nevada border, is made up of a few unincorporated to wns with populations ranging from zero to 20; mostly early railroad towns orig inally founded in the 1800’s. This area would be described as extremely rural and very remote. The eastern ar ea of the county could be considered as the northern most extension of the Ogden/Salt Lake /Provo megalopolis, even though it is separated from the Ogden Valley by 10 - 15 miles of open farmland and a moderately large recreation area (Willard Bay). The entire population of Box Elde r County amounts to less than 2 percent of the population found along the Wasatch Front.

The only monitored exceedances of the 0.075 ppm ozone standard in this county occurred at Brigham City which is located near the eastern edge of the county at th e foot of the Wasatch Range. Most of the sources of VOC and NO

x can be traced to area and mobile sources

associated with urbanization al ong the I-15/I-84 corridor. Box Elder County does have industrial sources that produce ozone precurs ors, but these sources are curre ntly not large enough to make Box Elder County a source area of ozone. Genera lly, whenever the monitor at Brigham City has recorded an exceedance of the NAAQS, the increas ed concentrations at the monitor have been

traced to areas located further s outh that are part of the major Wa satch Front core area. In these cases, a southerly wind flow carried the ozone pl ume north along the Wasatch Front as there is no substantial geography or topography separating this core area to the sout h from Brigham City.

Under the previous 8-hour ozone standard Box Elder County was designated as “attainment” for

ozone. Under the current 8-hour ozone standa rd (0.075 ppm), Box Elder County is still maintaining attainment level concentrations (2006 – 2008). Based mainly on this current monitoring data, Utah will recommend that B ox Elder County be desi gnated “attainment” for ozone. If future monitoring data (2007 – 2009) at the Brigham City monitor indicates that the area is not in attainment, then Utah would recommend that Box Elder County be designated nonattainment only for the townships east of th e I-15/I-84 junction. The remainder of the county, extending west to the Nevada border, would be recommended for a designation of “attainment/unclassifiable.” However, Box Elde r County is within the modeling domain, and all emissions from this county will be included in the modeling used to develop the SIP for ozone. Any source in Box Elder County found to have a significant impact on the nonattainment area

will be controlled as if it were in the nonattainment area.

Weber County

Much the same argument could be made for We ber County, in which all of the areas surrounding the selected townships are either located in high terrain or are part of the Great Salt Lake. There29 is, however, one notable exception; and that is the town of Huntsville, located east of the Wasatch Front in a high mountain valley. There is no reason to suspect that Huntsville, which has no industrial base, except for th ree ski resorts and a recreation reservoir, is not attaining the ozone standard, yet there is enough of a populat ion to warrant a careful consideration of sweeping regulations that need no t necessarily apply. Under the previous 8-hour ozone standard, all of Weber County was designated as an ozone maintenance area. Utah will recommend that all of Weber County, west of the ridgeline tracing the Wasatch Mountains, be designated “nonattainment” for ozone, with the remainder of the county, east of the Wasatch ridgeline, being recommended for a designation of “attainment/unclassifiable.”

Morgan County

Morgan County is located east of Davis County. It is separated from the metropolitan core areas of the Wasatch Front by the Wasatch Range. Th e town of Morgan surrounded by eight smaller towns and several family farms comprises the cente r of population in this ve ry rural county. The only industry in the county, the De vil’s Slide cement plant, is lo cated eight miles east of Morgan

in a mountainous area near the border with Summ it County. Ozone formation has never been a concern in Morgan County mostly because of it s rural setting, lack of ozone precursors and significant topographical separation from the Wasa tch Front. Utah will recommend that Morgan County be designated “attainmen t/unclassifiable.” However, Weber County is within the modeling domain, and all emissions from this c ounty will be included in the modeling used to develop the SIP for ozone. Any source in Morgan County found to have a significant impact on

the nonattainment area will be controlled as if it were in the nonattainment area.

Davis County

The only portions of Davis County not covered by the selected townships are over the Great Salt Lake. Under the previous 8-hour ozone standa rd, all of Davis County was designated as an ozone maintenance area. Utah will recommend that all of Davis County be designated

“nonattainment” for ozone.

Salt Lake County

The collection of townships used to define the non-attaining portions of Salt Lake County

includes all but the mountainous terrain in the ve ry western edge and approximately the eastern third of the county which is occupied by the Wa satch Range. There is some population present within the various canyons of this eastern range. In this case, DAQ feels it would be appropriate

to include these areas for the sake of vehicl e I/M and other regulatory programs. Under the previous 8-hour ozone standard, all of Sa lt Lake County was designated as an ozone

maintenance area. Utah will recommend that all of Salt Lake County be designated

“nonattainment” for ozone.

Summit County

Summit County is located directly east of Salt Lake City. It is separated from the Wasatch Front core area by a distance of between eight and te n miles and the very substantial Wasatch Front Range. As discussed earlier, Summit County ex tends eastward from the back of the Wasatch Range to the western and southern Wyoming borde r. Most of the population is located in the Park City area and the predominant industry ther e is tourism. There is one moderate point30 source located in Summit County, a shale processi ng plant, about ten miles from Park City in a very sparsely populated mountainous area. Furt her discussion of Summit County and the Park City area will be made in the “Consideration of Additional Areas” section following factor 9. Utah will recommend that Summit County be designa ted “attainment/unclassifiable.” However, Summit County is within the modeling domain, and all emissions from this county will be included in the modeling used to develop th e SIP for ozone. Any source in Summit County found to have a significant impact on the nonattainm ent area will be controlled as if it were in the

nonattainment area.

Utah County

Utah County is located directly south of the Salt Lake-Davis-Weber nona ttainment core area. Current monitoring data (2006 – 2008) from th e three DAQ monitors located in Utah County (see Table 3) show that all monitors are at or below the attainment level. Decreasing ozone concentration trends at these monitors show that the decreasing VOC and NO

x trends discussed

in factor 2 are slowing ozone formation in Utah Count y. Based on the most recent monitoring data, Utah will recommend that Utah County be designated as “attainment.” However, Utah County is within the modeling domain, and all emi ssions from this county will be included in the modeling used to develop the SIP for ozone. Any source in Utah County found to have a significant impact on the nonattainment area will be c ontrolled as if it were in the nonattainment

area.

If future monitoring data (2007 – 2009) at any of the Utah County monitors indicate that the area is not in attainment, then Utah would recommend that Utah County be designated “nonattainment” only for the townships west of the ridgeline tracing the Wasatch Mountain Range. The remainder of the county, extending east to Wasatch County would be recommended for a designation of “attainment/unclassifiable.”

Wasatch County

Heber Valley, the main populated area of Wasatc h County, is situated approximately fifteen miles northeast of Provo, Utah. It is a relativ ely high mountain valley whose main industry is farming and recreation. It is known for its crys tal clear air and breathtaking views. In recent years the population has seen an increased of re tirees from California settle in the valley because of its pristine climate. There are no threatening point sources located in Wasatch County and for

this reason Utah will recommend th at Wasatch County be designated “attainment/unclassifiable.” However, Wasatch County is within the modeling domain, and all emissions from this county will be included in the modeling used to develop the SIP for ozone. Any source in Wasatch County found to have a sign ificant impact on the nonattainment area will

be controlled as if it were in the nonattainment area.

Tooele County

Tooele County, like Box Elder County to the nort h, is a very large c ounty with a significant population and business presence located primarily south of US Interstate 80 and east of the Stansbury Mountain Range. Southwest of this range and extending to the Nevada border is the Utah Military Test Range and the Army’s Dugway Proving Grounds with a permanent population of zero.31 Under the previous 8-hour ozone standard, all of Tooele County was de signated as “attainment”

for ozone. Under the current 8-hour ozone st andard (0.075 ppm), Tooele County is still maintaining (2006 – 2008) attainment level concen trations. Based mainly on current monitoring data, Utah will recommend that Tooele Count y be designated “attainment” for ozone.

If future monitoring data (2007 – 2009) at the Tooe le monitor indicates th at the area is not in attainment, then Utah would recommend that Tooele County be designated nonattainment only for the townships east of the Stansbury Mountain Range. The remainder of the county, extending west to the Nevada border, w ould be recommended for a designation of “attainment/unclassifiable.” However, Tooele County is within the modeling domain, and all emissions from this county will be included in the modeling used to develop the SIP for ozone. Any source in Tooele County found to have a sign ificant impact on the nonattainment area will

be controlled as if it were in the nonattainment area.

Juab County

Juab County is located south of Tooele County a nd southwest of Utah County. It extends from

the Nevada border on the west to the Wasatch Ra nge on the east, an east-west distance of over 100 miles. The only sizeable popu lation, with the exception of less that 100 members of the

Goshute tribe located on th eir tribal land in the extreme northwest corner of county, is located in the far eastern end of the county. The main i ndustry is turkey farming and livestock on several large ranches near the eastern e nd of the county. There is one relatively small point source, the Leamington cement plant, located about twenty-five miles west of Nephi near the Millard County border. The air quality in Juab County is seldom influenced by air from neighboring Utah County due to the elevated ridge that makes up their common border. Utah will recommend that Juab County be designated “attainment/unclassifiab le.” However, Juab County is within the modeling domain, and all emissions from this county will be included in the modeling used to develop the SIP for ozone. Any source in Juab County found to have a significant impact on the nonattainment area will be c ontrolled as if it were in the nonattainment area; modeling will also include the Intermountain Power Plant located just south of Juab County in Millard County.

Washington County

Washington County is located in the very southw est corner of Utah. Currently data from the

Santa Clara monitor and the Zion National Park CA STNet monitor show ozone concentrations to

be well below the current standard. In 2005 the CASTNet monitor at the Zion National Park site recorded high ozone concentrations over a peri od of several days, but these higher recorded concentrations were directly attributable to wild fires that were located in the immediate vicinity

of the monitor. It should al so be noted again that CASTNet monitors do not meet the more stringent FRM or FEM requirement s specified in 40 CFR Part 58.

As the St. George area grows in both population a nd VMT, it is conceivable that the area could one day exceed the ozone standard. At th is time, however, Utah will recommend that Washington County be designa ted attainment for ozone.32 

### Factor 9. Level of Cont rol of Emission Sources

This factor will discuss the emission controls that are currently implemented for the major precursors of ozone, namely VOC and NO

x in the areas under consideration.

The control of emissions is governed by the Stat e’s Air Quality Rules which can be found at http://www.rules.utah.gov/ publicat/code/r307/r307.htm . These rules include emission inventories, control measures, and permitting and compliance limits. Emission controls and permit limits have been established to meet federal requirements and, as necessary, to meet applicable NAAQS.

As discussed previously, in areas where mete orological conditions are conducive to ozone episodes and the air becomes stagnant for several da ys at a time, it is likely that sources of VOC

and NO

x would coincide (in location) with areas monitoring high ozone concentrations. We have already noted the coincidence of populati on, low-land valley regions, and transportation

networks with a network of air monitors indi cating violations of th e 8-hour NAAQS for ozone.

That the emission sources would also be loca ted in these areas comes as no surprise. Nevertheless, this is one of the factors that must be evaluated in order to determine not only the core area(s) of nonattainment, but also those ar eas which may be contributing to violations

within these nonatta inment area(s).

Any inventory prepared by DAQ typically includes three categories of sour ces: large industrial point sources, area sources, and mobile sources. While the first and the last of these categories are more or less self explanatory, area sources ar e generally those of an i ndustrial nature that are

too small and too numerous within an urbanize d area to inventory on an individual basis. Instead, they are categorized, a nd emission factors are developed which relate these activities and their associated emissions back to population.

The emissions data used for this analysis is the same data that was reported to EPA and subsequently entered into the NEI database. It represents annual data from 2005, with some minor adjustments made to put mobile sour ce emissions on the same basis (mobile source emissions are typically calculated in terms of tons per day). Fo r each of these three categories,

VOC and NO

x emissions were evaluated. These gasses are known precursors to the formation of ozone and generally must be evaluated for emission reductions in nonattainment areas.

The focus area was on the area surrounding northern Utah. This area is often evaluated in rigorous computer modeling exer cises by DAQ, which enables the use of one such exercise which includes a “gridded” emissions inventor y within a modeling domain that includes the entire Wasatch Front and surrounding areas. In other words, within th e area of the domain shown in Figure 11, the emissions have been located in grid cells measuring one square kilometer each. This lends a high degree of accuracy to the analysis.

As discussed earlier, in the section on traffi c and commuting patterns, mobile source emissions are well represented by the dist ribution of population. Area s ources also show good correlation with the location of population. As discusse d before, many of the emission factors used to estimate emissions from area source categories are related to population. Good examples of this

would include fuel distribution or emissions related to industry. There are, however, other33 source categories for which population is not a go od surrogate. Included in this group would be emissions related to agriculture, such as agricult ural burning, harvesting a nd land preparation. A complete tabulation of the 2005 emissions invent ory for Utah has been included as Appendix 1

to this document.

Figure 12 shows the location of these emissions relative to the core set of nonattainment townships. It is apparent that the coincide nce of the two is very good, and for the reasons discussed above, this is to be expected. In the figure, point sources are identified by green circles

where size of the circle is indicative of the quantity of emissions produced by the source. The cut-point for inclusion as a point source was 100 tons/yr of combined NO

x and VOC. Smaller sources were simply included as area sources. The collection of point sources, along with the higher concentrations of area and mobile emissions, shows what might be considered a core urban area or areas within the proposed Wasatch Fr ont nonattainment region. This is consistent with the EPA’s definition of what the agency believed would characterize a typical urban

nonattainment area.

The addition of the emissions information serves to reinforce the notion of a core collection of townships that will be incl uded in the nonattainment area recommendations. These townships are representative of air quality data that i ndicates concentrations in excess of the 8-hour NAAQS for ozone. To a large extent, these to wnships are bounded by elevated terrain which acts to define low-land valleys within which summer air can become stagnant long enough for concentrations to become elevated. These township s also describe a region within which most of the population resides, and therefor e a region from which most of th e emissions that contribute to ozone originate.

It is apparent from Figure 12 that there are other areas of emissi ons located outside of the major

core area. Those areas will be discussed in th e next section. DAQ requires BACT on all major sources in compliance with federal law, and on all minor sources through our state only regulatory program. Any source found to have a significant impact on a nonattainment area will

be controlled as if it were in the nonattainment area.34 Figure 12. Emissions in Relati on to Core Nonattainment Areas

An indication of the point sources located in the CSA/MSAs is annotated in Figure 12 and a complete tabulation of their respective emissions is included as Appendix 2 to this document.35 

## Consideration of Additional Area s Outside the Wasatch Front Core

Area

In order to fully consider the smaller areas of em issions located outside the major core area, each

of these smaller areas will now be discussed with regard to fact ors pertinent to each respective area. The most important of these factors will be air quality data and t opography. Traffic and commuting patterns and projected growth will also be considered in the context of bedroom communities which may or may not impact the core nonattainment area.

In Figure 12, four areas have been identified; Park City and Heber Valley which lie to the east of the Wasatch Front, and Brigham City and the To oele Valley which lie west of the Wasatch Front. In addition, there are two other areas of the State not include d in the northern Utah “domain.” These are the greater St. George area of Washington County located in the southwest corner of Utah and San Juan County locat ed in the southeast corner of Utah.



### Park City, Summit County

Park City lies to the east of the Wasatch Mount ains in a relatively hi gh elevation valley (~6,500 ft.) called the Snyderville Basin. Park City itself is listed at an elevation of just over 7,000 feet. It was originally settled as a silver mining to wn in the 1870’s and was home to the Silver King Mine, the worlds richest silver mine. Park C ity is primarily a resort and bedroom community with significant commuter travel to and from the Salt Lake Valley. The Snyderville Basin is surrounded by high terrain to the west , south and southeast. July is the hottest month of the year but rarely, due to its elevation, does the temper ature rise above 80 degrees Fahrenheit. There are very few sources of ozone precursors in the area and, regular diurnal flow, in most instances, keeps the area crystal clear. The mo st significant aspect of the geogr aphy of the area is the lack of a connection to the Salt Lake Valley to the we st. The elevation of the pass (Parley’s Summit) connecting the Salt Lake Valley to the Snyderville Basin is 7,100 feet. This in essence does not allow any significant surface air movement between the two valleys. For these reasons, ozone formation is unlikely.

Park City, Utah looking southwes t toward the Salt Lake Valley36 Park City has a relatively small permanent popula tion that is enhanced in the winter season by large numbers of skiers. There is no data to indi cate that the air quality in Park City exceeds the NAAQS for ozone.

The only reason to possibly conclude that Park C ity contributes to violations in the Salt Lake Valley would be the level of vehicular traffic between the two areas. While it is true that Park City is considered somewhat of a bedroom comm unity to Salt Lake, the only implication for the

Salt Lake nonattainment area would be an influx of vehicles that are not required to meet the same level of Inspection/Maintenance as those re gistered along the Wasatch Front. Were Park City to be designated as nonattainment, it could implement an I/M progra m. Without a detailed analysis of Park City and its fleet of vehicles, it is not possible to qua ntify the benefit such a program might provide. However, a significant portion of these vehicles includes some degree of onboard diagnostic (OBD) equipment, and, theref ore, the influx of vehicles into the Wasatch

Front would not be characterized as an older fleet that woul d benefit greatly from an I/M

program.

Control of emissions at point source s would also not be an issue in this case. It is evident from Figure 12 that there are no major poi nt sources in Park City that could be affecting the Wasatch Front. Even if there were, it would be highly un likely that a significant degree of improvement

in emissions control would be achievable only through the SIP pro cess. Utah’s permitting rules already require Best Available Control technolo gy on all sources, major or minor, constructed

after 1971.

Growth estimates for the Park City area may be surmised from the countywide estimates provided by the Governor’s Office of Planning an d Budget. Park City is really the only populous region of Summit County, so it may be assumed that almost all of the countywide growth will take place in and around Park City. Table 6, located in the Factor 5 discussion, summarizes the projected population growth in the area s of interest to this analysis. Relative to the 2000 census, growth in Summit County is occurring at a rate of four to five percent per year. This is roughly twice th e average for the entire state, which is projected to be about two and a half percent per year. As a re ference point, population growth for the State of Utah during this same period is approximately 2.5 percent while th at of the United States during this same period is estimated as slightly less than one percent pe r year. This really comes as no surprise, as growth in Park City has been ve ry rapid throughout the last twenty years. Growth would be the primary reason that Park City ha s attracted the attention of DAQ.

Despite the high rate of growth, there is not enough weight of ev idence to determine that Park City be declared an area of nonattainment unto its elf. Nor will Utah recommend that Park City

be included in the Northern Wasatch Fr ont nonattainment area. A designation of

“unclassifiable” would be more a ppropriate for this area. However, Park City is within the modeling domain, and all emissions from this c ounty will be included in the modeling used to develop the SIP for ozone. Any source in Park City found to have a si gnificant impact on the

nonattainment area will be controlled as if it were in the nonattainment area.37 

### Heber Valley, Wasatch County

Heber Valley lies East of the Wasa tch Mountains, and Southeast of Park City. The Heber Valley is primarily a farming community with Heber City at its center. It is meteorologically distinct from the Wasatch Front, and is similar to Park City in terms of its topography. It is situated in a relatively high elevation valley th at experiences occasional temperature inversions during the

winter. There is minimal air movement between Park City and the Heber Valley, but due to recent increased home prices in Park City, the He ber Valley has become somewhat of a bedroom community to both Park City and the more popul ous Utah Valley area to the west. There is presently no I/M program implemented in Wasa tch County. Utah statute prohibits such a program unless the area is not atta ining one of the pertinent NAAQS.

Heber Valley, Utah looking so uthwest over Deer Creek Reservoir toward Provo Canyon

Figure 12 indicates that there are no major point sources in the Heber Valley that would warrant special consideration. Notwithstanding, it woul d be highly unlikely that a significant degree of improvement in emissions control would be ach ievable only through the SIP process. Utah’s permitting rules already require Best Availabl e Control Technology on all sources, major or minor, constructed after 1971.

The Heber Valley is a growing area. Growth es timates for the valley may be approximated by looking at the countywide estimates for Wasatch C ounty presented in Table 6 in factor 5. The Heber Valley is really the only populous region of Wasatch County, so it may be assumed that almost all of the countywide growth will take place in and around the valley. Relative to the 2000 census, growth in Wasatch County is occurring at more than five percent per year. Again, this is roughly twice the average for the entire state (roughly two a nd a half percent per year).38 As with Park City, rapid growth in a valley se tting is not sufficient reason to recommend Heber as an area of nonattainment. A designation of “u nclassifiable” would be more appropriate. However, the Heber Valley is within the modeli ng domain, and all emissions from this area will be included in the modeling used to develop th e SIP for ozone. Any source in the Heber Valley or Wasatch County found to have a significant impact on the nonattainment area will be

controlled as if it were in the nonattainment area.



### Tooele Valley, Tooele County

Figures 9, 10 and 11 reveal th e layout surrounding the Tooele Va lley which includes the City of Tooele and its neighboring towns of Grantsville and Stansbury Park . These municipalities reside to the West of Salt Lake County in the norther n half of a valley bound on the east and south by the Oquirrh Mountain Range and on the west by th e Stansbury Mountain Range. The Great Salt Lake is the northern boundary of this valley.

This topographical backdrop becomes important wh en discussing air movement between the Salt Lake and Tooele valleys. During a typical ozone episode in the Salt Lake Valley, the Oquirrh Mountains hinder any direct air movement between the two valleys. Diurnal air flows typically moves ozone plumes from the Salt Lake Valley no rthwestward out and over the Great Salt Lake. When the afternoon on-shore flow kicks in, sometimes there is just enough northward component to the wind to blow a fraction of th e ozone plume into the Tooele Valley. This phenomenon has been verified on several occasions by monitoring the timing of ozone concentrations at Salt Lake Valley monitors, the Beach monitor and the Tooele monitor.

Tooele Valley looking southeast from the eastern slopes of the Stansbury Mountains. Tooele City is located at mouth of the canyon at left cent er of photo. Grantsville is in the foreground.39 DAQ has been monitoring ozone in the Tooele Valley since 2005. A look at Table 1 for the Tooele monitoring site shows that, based on 2006-2008 data, the area has a decreasing ozone

trend and that the area is currently attaining the new ozone NAAQS.

If the Tooele Valley area were more geographi cally removed from the core Northern Wasatch Front nonattainment area, DAQs’ initial inclina tion would be to recommend a designation of “unclassifiable” and wait for more data. However, given its proximity to the core area, we will

consider additional information.

Figure 12 shows that it is far more likely that any potential impact due to industrial point sources would be directed from Salt Lake County into Tooele County rather than the other way around. This would be evaluated during the course of SIP development

. The only truly large point source in Tooele County is U.S. Magnesium LLC, lo cated more than 30 miles from either Tooele or the Wasatch Front. A 1997 Wasatch Front Ozone Study 6 showed that chlorine emissions from U.S.Magnesium do not significantly influence ozone formation in either Salt Lake or Tooele County. In addition, Utah’s permitting rules al ready require Best Ava ilable Control Technology on all sources, major and minor, c onstructed after 1971. It is unlik ely that a significant degree of improvement in emissions control would be ach ieved by designating the area as nonattainment.

Growth estimates for this area may be approxima ted by looking at the co untywide estimates for Tooele County presented in Table 6. The Tooe le Valley is really the only populous region of that county, so it may be assumed that the majo rity of the countywide growth will take place in and around Tooele Valley. Relative to the 2000 censu s, growth in Tooele County is occurring at more than four and a half percen t per year. Once again, this is roughly twice the average for the entire state, but actual numbers are very sma ll when compared to more populous areas. This would seem to indicate that growth will generally take place in and around previously developed areas, but that growth will be more rapid in th e peripheral areas that ar e not already built out. Tooele might be considered just such an area.

Commuting patterns represent another factor to be considered in this situation. According to information compiled for the 2000 census “Journey to Work” data 7 , Tooele County has 7,397

commuters that travel to one of the three counties comprising the northern Wasatch Front (Weber, Davis, and Salt Lake). By contrast, th ere are 9,784 commuters that travel only within Tooele County. This confirms that Tooele is very much a bedroom community. One might suspect a significant impact with in the Wasatch Front from cars or iginating in Tooele County. The Journey to Work data also reports that there are 619,397 commuters traveling only within

the northern Wasatch counties. From this it can be determined that the influx of cars from Tooele accounts for only about 1.2% of all commuter trips along the Wasatch Front.

Given the factors discussed above, DAQ is reco mmending that the Tooele County townships identified in Figure 12 be left out of the nonatt ainment area for the Wasatch Front. Of all the factors discussed so far, the air quality data colle cted in Tooele should be given the most weight. If the data collected here ultimately indicates that a nonattainment designation would in fact be

____________________ 6. “Wasatch Front Ozone Study,” prepared for th e Utah Department of Environmental Quality by ENVAIR and Alpine Geophysics, LLC, Volume 1, September 12, 1997

7. http:www.census.gov/population/www/cen2000/commuting.html#UT40 appropriate, then it will be addressed specifically for this area at that time. For now, it is recommended that the area be designated as “atta inment.” However, Tooele County is within the modeling domain, and all emissions from this county will be included in the modeling used to develop the SIP for ozone. Any source in Tooe le County found to have a significant impact

on the nonattainment area will be controlled as if it were in the nonattainment area.



### Brigham City, Box Elder County

The geographical and topographical layout of Brigham City can be seen clearly in Figures 9 and 10. Brigham City and its neighbor Tremont on (a farming community located 15 miles northwest), sit adjacent to the nor thern end of the Wasatch Mountai ns in the low lying area near the Great Salt Lake. Willard Bay, a prominent feature of the Lake, extends toward the East just

north of the border with Weber County (see Figure 11).

DAQ has been monitoring ozone in Brigham City since 2000. Current three-year monitoring data indicate that the area is attaining the current ozone NAAQS by a very close margin.

Looking east-northeast at Brigham City from west of I-15.

Similar to the Tooele area, if this area we re more geographically isolated, DAQ’s initial

inclination would be to recomm end a designation of “unclassifia ble” and wait for more data. Geographically speaking however, Brigham City is located very close to the northern edge of a core area that DAQ will recommend as nonattainment to the current ozone standard. For this

reason we need to consider some additional information.41 Looking more closely at emissions within this area, there are two major point sources worth mentioning. Nucor Steel is located just north of Tremonton, the uppermost township shown in Figure 12. As part of the permitting process, th is source has already undergone a BACT review.

There is no reason to believe that reclassification as a nonattainm ent area would have any affect

on the allowable emissions for this source. Another source of note is Vulcraft, a steel manufacturing facility, located just west of Brigham City. It is primarily a source of VOC emissions, but its NO

x emissions are negligible. It also unde rwent a BACT review as part of its permit application.

Growth estimates for Brigham City fall within the countywide estimate s for Box Elder County presented in Table 6. Brigham City and Tremont on are the only populous re gions of that county, so it may be assumed that almost all of the count ywide growth will take place within this general area. Relative to the 2000 census, growth in B ox Elder County is occurr ing at about 2.3 percent per year. This is a little less than the average for the entire st ate (roughly two and a half percent per year). While Brigham City might be considered as the northern extent of the Wasatch Front,

it is removed from the northern urbanized core of that area by about 20 miles of farmland. Likewise, Tremonton is removed from Bri gham City by about 15 miles of farmland.

Commuting patterns represent another factor to be considered for the Brigham City area. Looking again at the 2000 census Journey to Wo rk data, Box Elder County has 3,590 commuters that travel to one of the three counties (Weber, Davis, and Salt Lake) that make up the northern Wasatch Front core area. Actually the impact from this factor is even less that the impact from Tooele County commuting traffic. The Journey to Work data shows that only 3,590 commuters travel into the Northern Wasatch Front area counties for work. This amounts to approximately only 0.6 percent of the total travel within these core counties.

Given the factors discussed above, DAQ is recomm ending that the township s identified in Figure 12, within Box Elder County, not be included w ithin the Northern Wasatch Front nonattainment

area.

Of all the factors discussed so far, air quality da ta collected in Brigham City should be given the most weight. If the data colle cted here ultimately indicates that a nonattainment designation would in fact be appropriate, then it will be addre ssed specifically for this area at that time. For now, it is recommended that the area be designated as “unclassifiable.” However, Brigham City and Box Elder County are within the modeling domain, and all emissions from this county will be included in the modeling used to develop th e SIP for ozone. Any source in Box Elder County found to have a significant impact on the nonattainm ent area will be controlled as if it were in the

nonattainment area.



### Utah County

Utah County lies directly to the south of Salt Lake County. They are separated by a semiformidable elevation barrier of about five to eight-hundred feet (see figures 1 and 11). Air movement between the two counties does exist; ho wever, this barrier tends to keep that

movement to a minimum. The diurnal mountain-va lley flow in Utah County tends to be more east-west with only an occasional north-south component.

Concentrations of ozone precursors in Utah C ounty have been steadily decreasing for the last decade even though the population of the count y has increased. In 2002, Geneva Steel42 Corporation, the largest contri butor to both ozone and particul ate pollution in Utah County, ceased operations. In 2006 Ensign-Bickford, a la rge explosives manufacturer also ceased operations. From Table 1, we see that ozone concen trations at all three monitors located in Utah County show a slow but steady de crease over the past th ree years and that th e area is currently attaining the new ozone NAAQS.

Figure 12 shows that it is far more likely that any potential impact due to industrial point sources would be directed from Salt Lake County into Utah County rather than the other way around. This would be evaluated during the course of SIP development. The only significant VOC point source currently located in Utah County is the Pacific States Pipe Casting facility located south of Provo. Brigham Young University, also located in Provo, is the only ot her point source in the county and its VOC contribution to the inventory is minimal (see appendix 2). Utah’s permitting rules already require Best Available Cont rol Technology on all sources, major and minor, constructed after 1971. Hence, it is unlikely that a significant degree of improvement in emissions control would be achieved by designating the area as nonattainment.

Most of Utah County’s population currently resi des between Utah Lake and the Wasatch Range, extending from Lehi, northeast of Utah Lake, to Pa yson, southeast of Utah Lake. Areas of new development are beginning to emerge west of Utah Lake and between Spanish Fork and Santaquin in the south end of Ut ah Valley. Growth estimates for this area may be approximated by looking at the countywide estimates for Utah County presented in Table 6.

Utah County looking northeast toward the Wasatch Range from Salem, Utah

Commuting patterns represent another factor to be considered in this situation. According to information compiled for the 2000 census “Journey to Work” data 6 , Utah County has 19,318

commuters that travel to one of the three counties comprising the northern Wasatch Front (Weber, Davis, and Salt Lake). By contrast, th ere are 140,834 commuters that travel only within43 Utah County. This confirms that a great majority of Utah County residents both live and work in the county. Additionally, the Journey to Work data indicates that there are 619,397 commuters traveling only within the northern Wasatch Front c ounties. From this it can be determined that the influx of cars from Utah County accounts fo r only about 3.2% of all commuter trips.

The U.S. Census Bureau defines a CSA as an a ggregate of adjacent Core Based Statistical Areas that are linked by commuting ties. The lack of commuting ties between Utah County and adjacent counties to the north, as well as other significant social and economic considerations delineated in the U.S. Census, is what prompted the Department of Commerce to designate Utah County as a separate MSA and not include it in the larger Salt Lake-O gden-Clearfield CSA.

Given the factors discussed above, DAQ is recomm ending that Utah County not be included in

the nonattainment area for the Wasatch Front. Of a ll the factors discussed so far, the air quality data collected in Utah County should be given the mo st weight. If future data is collected that indicates that a nonattainment designation would be appropriate, it will be addressed specifically at that time. For now, it is recommended that Utah County be designated as “attainment.” However, Utah County is within the modeling do main, and all emissions from this county will be included in the modeling used to develop the SIP for ozone. Any source in Utah County found to have a significant impact on the nonattainm ent area will be controlled as if it were in the

nonattainment area.



### St. George, Washington County

As can be seen in Figures 2 and 3, there is one metropolitan area in southwestern Utah that deserves some discussion. This area is generally referred to as St. George, after the largest city in the area. The area is made up of the cities of St. George, Bloomi ngton, Washington, Santa Clara, Hurricane and several other smaller towns.

Based on the monitoring requirements of 40 CFR Pa rt 58, St. George does not presently have a large enough population to requir e a federal reference monitor for ozone. Nevertheless, DAQ has conducted “survey” monitoring in St. George City since 2004. In 2008 the “survey” monitor

was relocated about two miles north west to the town of Santa Clar a to eliminate any effect of

NO

x scavenging from nearby Interstate 15 and to give a better indication of ozone transport from the Las Vegas area. Results of this survey monitoring from the combined St. George (2006- 2007) and Santa Clara (2008) monitors indicate th at summer ozone values have remained well below the current 75 ppb standard. Actual results for the 2006-2008 monitoring seasons from the St George and Santa Clara sites show that the three-year average of the 4 th highest ozone concentration at the monitors was 64 ppb. Ther e is also a CASTNet m onitor located near the south entrance to Zion National Park; the three year average of the 4 th highest ozone concentrations monitored there is 73 ppb (see Ta ble 2). This difference can be explained by severe wildfires in 2005 and again in 2006 just we st of the Zion monitor. In one instance, confirmed by National Park Service officials, the wildfire actually burned right up to the monitoring site.

The St. George area lies at an elevation of onl y 2,600 feet MSL on the periphery of the Mojave

Desert. There are mountainous areas to the north and west, but the area is not confined and does not stagnate here like it does in the lower valleys along the Wasatch Front.44 St. George looking northeast, approximately 35 miles, toward Entrance to Zion National Park

The St. George area has seen significant growth, as a retirement community, over the past twenty years and this growth is expected to continue, as noted in Table 6, for the foreseeable future. Based on the results of “survey” monitoring in th e center of the St. Geor ge area, and also the monitoring results at the Zion National Pa rk CASTNet monitor, DAQ will recommend a classification of “attainment/unclassifiable” for this area. DAQ will continue “survey” monitoring at the Santa Clara site and may instal l a federal reference monitor in the area in the

future.



### San Juan County

San Juan County is located in the southeast corner of Utah. This county is part of the FourCorners region, and borders the States of Colo rado, New Mexico, and Arizona. The southern portion of San Juan County is part of the Navajo Nation. San Juan County is sparsely populated and oil and gas production is the primary source of emissions in the area. There is one major

source located in the northeastern portion of the county, the Li sbon Natural Gas Processing Plant operated by EnCana Oil and Gas (USA) Inc. The oil and gas fields in San Juan County have been producing for many years, and production has been decreasing steadily over the last decade as can be seen in Figure 13. A significant portion of the oil an d gas production in the county is occurring on tribal land under the jurisdiction of the Navajo Nation.45 Oil and Gas Production in San Juan County, Utah

- 5,000,000 10,000,000 15,000,000 20,000,000 25,000,000 30,000,000 35,000,000 40,000,000

1980 1985 1990 1995 2000 2005 2010barrels oil/MCF gas

Oil

Natural Gas

Figure 13. Oil and Gas Producti on in San Juan County, Utah

DAQ does not have an ozone monitor in San Juan County, however, the National Park Service

maintains a CASTNet monitor in Ca nyonlands National Park in the no rthern part of the county. The 3-year average for this monitor is 0.071 pp m (see Table 2), and is an indicator that the county is attaining the ozone standard.

San Juan County in Utah adjoins San Juan C ounty in New Mexico where ozone values just

above the standard have been measured at th e Navajo Dam site. Emissions from San Juan County, Utah are unlikely to significantly contribu te to ozone concentrations at this monitor. The Navajo Dam monitoring site is located appr oximately 80 miles from the Utah border, and

two ozone monitors that are located between the Utah border and Navajo Lake monitor are attaining the standard. There has been signifi cant oil and gas development in the Four Corners region in the last decade, but this has occurred pr imarily to the south and east of Utah’s border, in Colorado and New Mexico, and production has b een declining in Utah. The 2002 base year inventory (plan02b) that was compiled by the West ern Regional Air Partnership (WRAP) shows oil and gas area source emissions for San Juan County Utah to be 286 tons per year NOx and 1,477 tons per year VOC. In comparison, oil a nd gas area source emissions for San Juan County New Mexico were 20,041 tons per year NOx and 60,178 tons per year VOC.46 Canyonlands National Park, San Juan County, Utah

Based on monitoring data in the area, ozone levels are below the NAAQS, and the limited

contribution of emissions from Colorado and Ne w Mexico, San Juan County Utah should be designated as attainment/unclassifiable for ozone.47 

## State Recommendations

Wasatch Front

As shown on Figure 14, Utah is recommending the establishment of one nonattainment area for

ozone: The Northern Wasatch Front nonattainment area which includes all of Salt Lake County, all of Davis County and all portions of Weber County west of and including Townships 5 & 6 North Range 1 West and all portions of To wnship 7 North Range 1 West that are in Weber County and west of the ridgeline that traces the Wasatch Mountains from the Southeast corner of the township to the easternmost extension of the county boundary.

Figure 14. Recommended Ozone Nonattainment Area48 

### Attainment/Unclassifiable Areas

As shown on Figure 15, Utah is recommending that all portions of the State not identified as areas of nonattainment should be designated as ei ther “Attainment” or “Unclassifiable” with respect to ozone. An exception to this recommen dation is all Indian C ountry Lands within the State of Utah over which DAQ has no jurisdiction. Designation of those areas will be left to

EPA’s discretion.

Figure 15. Statewide Area Map showing Recomm ended Nonattainment Areas and Indian Lands49 

### Summary Table

Table 9 provides a description of all areas of the State and the recommended designations they should carry with respect to ozone. The State does not make recommendations for any portions of any county designated as Indian Country.

Table 9. Description of all Areas of Utah and Recommended Designations County Attainment Unclassifiable Nonattainment Nonattainment Area

Beaver X X

Box Elder X
Cache X
Carbon X X Daggett X X

Davis X Northern Wasatch Front

Duchesne X X Emery X X
Garfield X X
Grand X X

Iron X X

Juab X X

Kane X X

Millard X X Morgan X X

Piute X X

Rich X X
Salt Lake X Northern Wasatch Front

San Juan X X Sanpete X X
Sevier X X
Summit X X

Tooele X

Uintah X X

Utah X

Weber All portions of Weber County not otherwise designated

nonattainment All portions of Weber County west of and including T5N R1W

and T6N R1W and all portions of T7N R1W

that are in Weber County and west of the ridgeline that traces the

Wasatch Mountains

from the Southeast corner of the township

to the easternmost extension of the county boundary Northern Wasatch Front

Wasatch X X Washington X Wayne X X50 

## Supporting Documentation

In addition to any technical information doc umenting the recommendation for area boundaries, EPA requested that each state provide the informati on identified below. Th e italicized text either provides or indicates where this information ha s been included with Utah’s recommendation.



### For nonattainment areas:

• The ozone design value(s) for the area

• The 3-yr period represented by the design value(s) All of the information identified above was included in Table 1.

• Site locations and ID numbers (see Table 10)

Table 10. DAQ Monitor Network Lo cations (*Denotes monitors that are currently inactive or in the process of being repositioned) Site ID Location Address County 49-003-0003 Brigham City 140 W. Fishburn Box Elder 49-005-0004 Logan 125 W. Center St. Cache

49-011-0004 Bountiful 171 W. 1370 N. Davis

49-035-0003 Cottonwood 5715 S. 1400 E. Salt Lake

49-035-2004 Beach 12100 W.1200 S. Salt Lake

49-035-3006 Hawthorne 1675 S. 600 E. Salt Lake 49-035-3007 West Valley* 3275 W. 3100 S. Salt Lake

49-035-3008 Herriman* 12950 S. 5600 W. Salt Lake

49-045-0003 Tooele 434 N. 50 W. Tooele

49-049-0002 North Provo 1355 N. 200 W. Utah 49-049-5008 Highland 10865 N. 6000 W. Utah 49-049-5010 Spanish Fork 312 W. 2050 N Utah 49-057-0007 Washington Terrace* 4601 S. 300 W. Weber 49-057-0002 Ogden #2 228 E. 32 nd St. Weber

49-057-1003 Harrisville 425 W. 2550 N. Weber



### For attainment/unclassifiable and nonattainment areas:

• Names of counties and tr ibal lands included, (See Summary Table and Figure 15)

• If partial counties or portions of tribal lands are included, the boundary definition/description is presented in Figure 15

o including a legal definition of the area (See Summary Table and Figure 15)

o an explanation of how the boundary is cons istent with Sect. 1 07(d)(1) of the CAA51 Paragraph (A) of section 107(d)(1) of th e Clean Air Act describes the three designations an area may carry (see page 10) Utah’s recommendations are consistent with the definitions provided therein.

The areas recommended for designation of “Nonattainment ” are areas represented by monitored ambient air data that does not meet the primary (or secondary) 8-hr standard for ozone. The recommendations for these areas were not completed until surrounding areas were evaluated to s ee whether they were impacting upon the

areas.

The areas recommended for designation of “Attainment ” are represented by

monitored ambient air data that does meet all the primary and secondary standards for ozone.

The areas recommended for designation of “Unclassifiable ” are areas for which there is insufficient data to draw any conclusions.



## Names of contacts

M. Cheryl Heying Dave McNeill Director Section Manager Utah Division of Air Quality SIP Section (801) 536-4022 (801) 536-4037

Robert Clark Kimberly Kreykes Environmental Scientist Environmental Planning Consultant

SIP Section SIP Section (801) 536-4435 (801) 536-404252 

## Appendix 1

2005 Emission Summary by County

County Source NOx VOC County Source NOx VOC

Beaver Area Source 58.22 295.40 Piute Area Source 13.01 153.57

Non-Road Mobile 3238.97 44.43 Non-Road Mobile 6.32 76.97

On Road Mobile 1119.45 472.10 On Road Mobile 118.90 52.48

Point Source 42.30 3.36 Point Source 0 0

Total 1548.95 815.29 Total 138.24 283.02

Box Elder Area Source 535.24 2992.59 Rich Area Source 48.14 223.45

Non-Road Mobile 553.15 2471.33 Non-Road Mobile 8.41 375.00

On Road Mobile 3976.10 1523.03 On Road Mobile 188.04 95.46

Point Source 553.36 395.78 Point Source 0 0

Total 5617.85 7382.73 Total 244.58 693.91

Cache Area Source 356.86 2437.75 Salt Lake Area Source 1901.72 19963.22

Non-Road Mobile 666.98 612.97 Non-Road Mobile 5184.10 5452.65

On Road Mobile 2928.08 1269.39 On Road Mobile 23310.31 9574.62

Point Source 139.74 143.84 Point Source 7710.29 2130.76

Total 4091.66 4463.96 Total 38106.41 37121.25

Carbon Area Source 86.33 482.12 San Juan Area Source 35.39 516.76

Non-Road Mobile 939.09 134.89 Non-Road Mobile 59.24 546.10

On Road Mobile 992.42 363.57 On Road Mobile 1057.86 470.43

Point Source 3981.86 66.30 Point Source 473.29 67.32

Total 5999.70 1319.88 Total 1625.78 1600.60

Daggett Area Source 34.63 240.32 Sanpete Area Source 120.29 619.97

Non-Road Mobile 19.37 144.47 Non-Road Mobile 47.05 177.06

On Road Mobile 113.62 74.29 On Road Mobile 981.81 566.38

Point Source 749.18 66.44 Point Source 32.79 2.68

Total 916.81 525.52 Total 1118.94 1366.09

Davis Area Source 340.98 5534.81 Sevier Area Source 144.36 685.69

Non-Road Mobile 1824.27 1635.73 Non-Road Mobile 170.84 402.08

On Road Mobile 6423.47 2904.61 On Road Mobile 2975.83 675.07

Point Source 2152.47 1559.60 Point Source 132.05 11.27

Total 10741.19 11634.75 Total 3423.09 1774.11

Duchesne Area Source 80.34 747.49 Summit Area Source 155.96 913.20

Non-Road Mobile 148.48 277.51 Non-Road Mobile 1386.09 422.81

On Road Mobile 979.01 372.29 On Road Mobile 2148.08 833.84

Point Source 656.54 260.62 Point Source 472.20 28.37

Total 1864.36 1657.91 Total 4162.33 2198.2153 Source NOx VOC County Source NOx VOC Source

Emery Area Source 60.28 372.35 Tooele Area Source 298.21 2157.66

Non-Road Mobile 160.31 63.08 Non-Road Mobile 1337.40 968.26

On Road Mobile 1595.53 663.40 On Road Mobile 2647.99 1767.52

Point Source 28206.90 236.27 Point Source 1210.20 509.42

Total 30023.02 1335.11 Total 5493.79 5402.86

Garfield Area Source 71.29 465.10 Uintah Area Source 111.08 1018.01

Non-Road Mobile 76.77 656.26 Non-Road Mobile 174.94 233.48

On Road Mobile 478.18 208.14 On Road Mobile 1394.03 571.08

Point Source 7.40 0.93 Point Source 150.19 50.68

Total 633.64 1330.42 Total 1830.25 1873.25

Grand Area Source 15.61 285.30 Utah Area Source 780.77 9391.55

Non-Road Mobile 175.71 904.50 Non-Road Mobile 2674.25 2087.73

On Road Mobile 1042.04 572.12 On Road Mobile 9483.84 5116.22

Point Source 377.81 68.68 Point Source 652.69 719.84

Total 1611.18 1830.60 Total 13591.55 17315.33

Iron Area Source 187.91 1193.72 Wasatch Area Source 46.20 457.91

Non-Road Mobile 194.27 223.96 Non-Road Mobile 206.76 131.49

On Road Mobile 2815.06 1058.78 On Road Mobile 907.21 445.65

Point Source 72.07 99.09 Point Source 67.23 5.95

Total 3269.32 2575.54 Total 1227.40 1041.00

Juab Area Source 123.04 785.43 Washington Area Source 841.90 7193.25

Non-Road Mobile 805.06 200.55 Non-Road Mobile 724.59 1285.40

On Road Mobile 2292.07 695.29 On Road Mobile 4524.91 1904.83

Point Source 1536.13 62.85 Point Source 196.30 57.19

Total 4756.30 1744.12 Total 6287.69 10440.66

Kane Area Source 25.89 196.92 Wayne Area Source 31.00 89.49

Non-Road Mobile 58.96 715.20 Non-Road Mobile 19.71 212.24

On Road Mobile 552.50 272.59 On Road Mobile 157.71 85.20

Point Source 0 0 Point Source 15.97 1.24

Total 637.35 1184.71 Total 224.39 388.17

Millard Area Source 95.96 578.36 Weber Area Source 304.56 4535.39

Non-Road Mobile 1289.10 685.07 Non-Road Mobile 1674.89 1238.53

On Road Mobile 2315.55 797.10 On Road Mobile 4479.23 2399.52

Point Source 23316.67 130.85 Point Source 421.78 172.80

Total 27017.27 2191.38 Total 6880.46 8346.23

Morgan Area Source 26.83 263.76 Statewide Area Source 6932.02 64790.53

Non-Road Mobile 1297.00 99.52 Totals Non-Road Mobile 22212.08 22479.27

On Road Mobile 513.63 199.55 On Road Mobile 82449.48 36277.54

Point Source 1333.03 50.98 Point Source 74660.42 6903.09

Total 3170.50 613.81 Total 186,254.0 130,450.454 

## Appendix 2

Point Sources located in CSA/MSA Factor 9

Site ID Plant County VOC (tpy) NOx (tpy)
10007 Holcim (US) Inc - Devil’s Slide Morgan 49.4 1,324.5

10008 Nucor Steel Box Elder 79.6 238.9 10028 Vulcraft - Steel Products Manufacturing Box Elder 239.6 4.8 10119 Chevron Salt Lake Refinery Davis 257.7 783.8

10121 Hill Air Force Base - Main Base Davis 247.3 142.2 10122 Flying J Refinery Davis 384.7 374.5 10123 Holly - Phillips Refinery Davis 198.4 324.6 10124 Silver Eagle Refining Davis 178.0 85.2 10129 Wasatch Waste Mgmt County La ndfill Facility Davis 24.2 280.8 10156 Utility Trailer Manufacturing Davis 106.7 38.8 10303 Ash Grove Cement Company Juab 57.5 1,397.6 10335 Tesoro Salt Lake City Refinery Davis 268.2 446.5 10346 Kennecott Smelter & Refinery Salt Lake 8.7 154.7 10565 Geneva Rock Pt of the Mountain Facility Salt Lake 16.3 86.0
10571 Kennecott Mine & Concentrator Salt Lake 344.6 3,750.0 10572 Kennecott Power Plant/Lab/Tailings Salt Lake 11.9 2,066.6 10676 Utelite Corp - Shale Processing Summit 2.6 235.2 10716 US Magnesium - Rowley Plant Tooele 452.5 746.9 10725 Clean Harbors Aragonite - Hazardous Waste Incineration Tooele 6.2 131.9 10790 Brigham Young University Main Campus Utah 9.7 98.8 10794 Pacific States Pipe Ca sting Plant Utah 303.5 65.0 10973 PacifiCorp Little Mountain Power Plant Weber 1.7 200.6 11339 Desert Chemical Depot Tooele 4.0 108.4 11841 Pepperidge Farm Commercial Bakery Cache 120.5 4.4

12519 Tooele Power - Desert Power Plant Tooele 2.7 144.7