### 2007 EMISSIONS INVENTORY UPDATE FOR THE GILA RIVER INDIAN COMMUNITY

Assistance ID No. 

### A-98920909-0 U.S. Environmental Protection Agency, Region IX

For Submittal To: Ms. Deborah Jordan U.S. EPA, Region IX 

### 75 Hawthorne Street, Air 

### 1 San Francisco, California 

### 94105

Submitted By: Gila River Indian Cornm~.~nity Department of Environmental Quality P.O. Box 

### 97 Sacaton, Arizona 

### 85247 (520) 562-2234 (520) 562-2245 Fax Prepared By: Daniel C. Blair Compliance and Enforcement Manager
January 

### 2009

### TABLE OF CONTENTS



# ........................................................................................... 1 EXECUTIVE SUMMARY 1 2 INTRODUCTION

# ....................................................................................................... 2 2.1. Background

............................................................................................. 

### 2 2.2. StudyArea

................................................................................................. 

### 3 

### 3 METHODOLOGIES

## ................................................................................................... 4 

### 3.1. Point Sources



### ............................................................................................ 4

............................................................................................. 

### 3.2. Area Sources 4 3.3. Mobile Sources

.......................................................................................... 

### 5 4 

### SUMMARY OF RESULTS

## .........................................................................................6 

### 5 POINT SOURCES

# ..................................................................................................... 7 5.1. Ongoing Sources

....................................................................................... 

### 7 5.2. New Sources

.......................................................................................... 

### 9 5.3. Discontinued So~~rces



### ............................................................................. 10 5.4. Facilities Below PermittingAnd Reporting Thresholds

............................ 

### 10 

### 6 AREA SOURCES

# ....................................................................................................12 7 MOBILE SOURCES

# ................................................................................................ 13 7.1. Nonroad

................................................................................................... 

### 13 7.2. Onroad



### .................................................................................................... 13 7.2.1. Data Collection

........................................................................ 14 7.2.2. Calculation Methods

................................................................. 

### 15 8 

### REFERENCES

## ........................................................................................................ 17
FIGURES 1 Map of the Gila River Indian Community. Arizona 2 Map of Gila River IndianCommunity. Maricopaand PinalCounties. and 

### PMIO NonAttainment Area 3 Map of Agricultural Areas on the Gila River Indian Community

### 1 

### EXECUTIVE SUMMARY This report contains the 2007 Emissions Inventory(El) Update (2007 El) conducted within the exterior boundaries of the Gila River Indian Community (GRIC). An El is an itemized list of emission estimates for sources of air pollution in a given area for a specified time period. This 2007 El is an update to the original El that was developed and submitted for 1997. Therefore, it should be recognized that emission sources may fluctuate drastically within the 10- year time frame only to return to their original levels when the next 10-year El update is conducted. Similarly, due to fluctuating market conditions and changestolimplementation ofthe GRIC Master Plan, emission sources in years preceding and following the El update may be dramatically different (or absent) from the year the El update was completed.. Some sources (e.g., construction) did not significantly contribute to the overall err~issions during ,theyears in which the Elswere conducted and were, therefore, not included in the 1997 and 2007 Els. The 2007 El includes emissions from point sources, area sources, onroad mobile, nonroad mobile and non-anthropogenic sources of air pollution. The inventory provides emissions estimates for carbon monoxide (CO), nitrogen oxides (NOx), sulfur oxides (SOX),volatile organic compounds (VOCs), and particulate matter less than 10 microns in diameter (PM10). Emissions of lead were not calculated since there are no significant sources emitting ambient lead emissions within the Community and leaded gasoline is no longer available in Arizona. Emissions were calculated using several methods including mass balance, best engineering estimates, AP-42 emissions factors, CARB emissions factors, performance test results, permit applications, Mobile 6 model outputs from the Maricopa Association of Governments (MAG), vehicle traffic counts, Maricopa County emissions factors and the State of Arizona emissions factors. Emissions inventories from several individual facilities were developed by private consultants or in-house environmental personnel, using the above calculation methods, information gathered from site visits, and these were reviewed by GRIC's Compliance and Enforcement Manager (CEM). Since the Community experiences relatively slow growth when compared with the growth of corrlmunities like Metropolitan Phoenix, some of the emissiondata from the 1997 Elwas carried over to this 2007 El Update. For example, the levels of open burning and residential burning have remained relatively constant and many small stationary sources have also experienced little or no growth since 1997. Also, many of the small stationary sources do not keep accurate production data records because the facilitiesare belowthe permittingand reporting thresholds. The Gila River Tribal Council has recently approved an Air Quality Management Plan (AQMP), which allows for the irr~plementation of an air quality regulatory program, permitting program, and a compliance inspection program. The Community's Air Quality Department is in the process of developing their first set of Non-Title V air quality permits for several industries located on the Community.2.1. 

### Background The Gila River lndian Community (GRIC),a federally-recognized tribe, is a ruralcorr~munity located on approximately 374,000 acres in south- centralArizona, adjacenttothe southern border of Phoenix, Chandler and Gilbert, with an on-reservation population of approximately 15,500 people (Figures 1 

### & 2). The reservationwas established in 1859 by Executive Order with Congressional approval. Members of the Gila River Indian Community are Akimel O'odham (Pima) and Pee Posh (Maricopa) and form the fourth most populous lndian Reservation in the United States. On the northern boundary, the Community is adjacent to the rapidly growing Phoenix metropolitan area. A portion of the Community (92,000 acres) lies within Maricopa County. This portion of the GRlC is located within the Federal Non-AttainmentArea for particulate matter lessthan 10 microns (PMIO), which has been classified as "serious" by EPA (Figure 2). It is currently undeterminedto what extentair pollution from the Phoenix metropolitan area affects air quality within GRlC boundaries. The Community hasthree (3) industrial parks containing approximately50 industrial plants along with several industrial facilities located in out-lying areas. The Lone Butte Industrial Park, the largest of the three industrial parks, lies within the Maricopa County nonattainment area and includes one Federally-regulated major source (Pimalco). The remaining two industrial parks are much smaller and contain only minor sources of air pollution. Agricultural production throughout the Community has not changed significantly since 1997. There are currentlyapproximately35,000 acres inagricultural production throughout the Community. Approximately 6,700 agricultural acres are located within the Maricopa County non-attainment area. The largestsource of air pollution within the Community isvehicleemissions. Interstate 1 0 is the single largest source of pollution with approximately 1,400,000 vehicle milestraveled (VMT) daily. GRlC has approximately 160 niiles of unpaved roads that are very rarely traveled and consist mainly of farm roads and roads accessing very remote areas. The Maricopa County PM10 non-attainment area was designated in 1974to include the urbanized portions of Maricopa County but also included the northern portion of GRlC (Figure2). The boundarywas arbitrarily developed based on the Maricopa Association of Governments (MAG) operational area and did not includeany scientific information from GRlC to support the non-attainment designation. GRlC was not allowed to comment during the designation process nor was scientific evidence from GRlC usedto determine the boundaries of the nonattainment areas. No evidence has ever indicated that any portionof GRlC is in non-attainmentor even contributestothe non-attainmentstatuswithin Maricopa County. GRlC plansto conduct additional monitoring inthe futureto supportthis position.

### The Community is facing several issues arising from the non-attainment status of the northern portion of the Community, including NSR and Title 5 permittirlg requirementsfor new industrial facilities plannirlg to locate within the Community. The Gila River Tribal Council has recently approvedanAir Quality Management Plan (AQMP), which allowsfor the implementation of an air quality regulatory program, permitting program, and a compliance inspection program. The Community'sAir Quality Department is in the process of developingtheir first set of Non-Title

### V air quality permitsfor several industries located on the Community. 

### 2.2. Study 

### Area The Gila River IndianCommunity extends from the towns of Phoenixand Chandler on the north, south to almost Casa Grande,to the Estrella Mountainson the west to Coolidge on the east (Figure 2). The Gila River Indian Community lies in Sonoran Desert terrain that is primarily light scrub and cactus with an elevation of approximately 1,200 to 1,400 feet above sea level. The temperature varies from approximately20°F in the winter to >I15°F in the summer. Annual precipitation is light with approximately 36 days peryearwith >0.01 inches. Wind speed and direction can vary, but generally the wind blows from the southwest to the northeast in the morning and reverses direction in the afternoon. Wind speed can varyfrom a slight breezeto 70 mile per hour winds during the monsoon season.To update the 1997 El, the Gila River Department of Environmental Quality (DEQ) assessed both stationary and mobile source emissions. 

### 3.1. Point Sources For the purposes of this El, point sources are defined as stationary facilities (with point and/or area sources) within the boundaries of the Community. The point sources listed in 1997 El were divided into the following five categoriesfor this update: 1. Ongoing (since 1997); 2. Ongoing with changed names (since 1997); and 3. New (operating in 2006 but not in 1997); 4. Discontinued (not operating in 2006); 

### 5. Below the permitting and reporting thresholds. Emissions for the new point sources were developed using information supplied by the source or obtained during site visits pertaining to the type of processes employed, the types of materials/chemicals used, quantities of materials input to processes and type of pollution control equipment operated. After collectingthis data, emissionswere estimated usingAP-42 emissions factors, mass balance equations, source test information, and best engineering estimates. Several of the new sourceswere in operation for only a short period of time in 2007 or did not have readily available productiondata. Therefore, these sourceswere included under a category with facility emissions belowthe permittingand reporting threshold. Emissions from these sourceswill be included inthe next GRlC El, provided the emissions from these facilities exceed the permitting and reporting threshold. The Community's Air Quality Department is in the process of developing their first set of Non-Title

### V air quality permits for several industries located on the Community. This process will continue until all sources required to have a permit within the community are permitted. All permitted sources will be required to submit an annual El to the GRlC DEQ as a condition of their operating permit. 

### 3.2. Area Sources Area source emissions include open burning emissions, agricultural emissionsfrom tillage and harvesting, and construction emissions. There has been little or no net change inthe quantities of open burningand construction emissions since 1997;therefore, the 2007 area source emissions were assumed to be identicalto 1997 area source emissions for thesesources. Agric~.~ltural-related emissionswere adjusted for a slight increase inthe amount of land under agricultural production between 1997 and 2006. 

### 3.3. 

### Mobile Sources EPA's Mobile 6 model was used to estimate emissions from onroad mobile sources (vehicletraffic). Emissionsof PMI0 from dirt roads and from paved roadswere estimated using formulas provided inAP-42. Vehicle countsand road n-~ileages were obtained for the most recent year available from the Arizona Department of Transportation (2006), GRlC Department of Transportation (2003, 2004), Maricopa County Department of Transportation (2005), and MAG (2005).4 SUMMARY 

### OF RESULTS 

### Annual emissions estimates were developed for the five criteria pollutants 

### - PMI0, CO, NOx, SOXandVOCs. A summary of the 

### 2007 criteria pollutantemissions from each of the three sources categories is shown in Table 

### 4.1. TABLE 4.1 Summary of Source Emissions (tonslyr)

Point Mobile Area TOTAL 1,048 386 759 2,193 161 10,588 63 10,812 175 2,055 52 2,282 142 929

56 1,127 31 37

0 68

### 5 POINT SOURCES For the purpose of this inventory, point sources are defined as stationary facilitieswithin the boundaries of the Community. The point sources from the 1997 Elwere divided into the following five categories for this update: 1. Ongoing (since 1997); 2. Ongoing with changed names (since 1997); and 

### 3. New (operating in 2006 but not in 1997); 4. 

### Discontinued (operating in 1997 but not in 2006); 5. Below the permitting and reporting thresholds. A summary of the emissionsfrom the new and ongoing pointsources is presented inTable 5.1 below. TABLE 5.1 Point Source Emissions (tonslyr)

"-" = zero value or not applicable


### 5.1. Ongoing Sources Ongoing point sources on the Community are those sources that were operating in 1997 and 2006. Several orrgoingfacilities also underwent a name change since 1997. Available emissions data is limitedfor these ongoing sources because most ofthe sources do not currently havean air quality permit. Also, most of these sources have not changed significantly since 1997. Therefore, with the exception of two facilities (Rinker's Maricopa and Santan plants),the 1997 El emissions data was used for the 2007 El Update. A surrlmary of the ongoing sources (without a name change) and their associated emissions is presented in Table 5.2.

### TABLE 5.2 

### ongoing' Point Source Emissions(tonslyr)



# I Bondurant 19 

## 1 4 

## 1 2.57

## 1 I Casa Blanca MKT 

### I - 

### I - 

### I - 

### I 3.1 

### 1 - 

### I 

# I Classy Closets 0.3 

## 1 - - 

## voe 2 0.17 - Saum 

## t, plm,,,,



### I DBCl 

### I - 

### I 

### - I 

### - I 

### - I - 

### I GO.

0.05 - 

### - EiOx Alexco Arizona Box BMC West . -. 0.24 - 0.02

0.2



# I Pima Valve 0.28

## 1 

# 1

Fertizona San Tan Firebird Raceway Gila River Farms Gin Gila River Gas Station Komate gas station (53Ave & Pecos Rd) KT Fabrication Pacific Scientific 

# I Rock Solid 9.5

## 1 - 

### I Romic 

### I - 

### I - 

### I - 

### I 3.3 

### 1 

### - I 0.67

6.7



# 1 Therm-0-Rock West 48.7

## 1 1.8 

## 1 7.4

## 1 0.2

## 1 0.03

# 1 I Triangle Truss 0.4

## 1 0.1 

## I - - 1.7



### A summary of the ongoing sources with a name change, their former name, and their associated emissions is presented in Table 

### 5.3. 13

Wilbur Ellis TOTAL



# I Honeywell 

## I Allied Signal 2.8

## 1 11.3

## 1 3.6 

## 1 8 

## 1 3.2

### ] 0.22 - 0.75

10 5.1 - 0.03

"-" = zero value or not applicable 

### ' = Operating in 1997 and 2006 

### - 73.35



### TABLE 5.3 

### Ongoing Changed ~ame' Point Source Emissions (tonslyr)



### I KaiserAluminum 

### I Plvmouth Tube 

### I 0.11 

### 1 0.19 

### 1 0.93

### 1 9.9 

### 1 - 

### I - - -

-



### setme Animal Nutrition 

### I MTD 

### I Rvobi 

### 1 0.024 

### 1 8.4 

### 1 0.006 

### 1 3 

### 1 0.003

### 1 53.5



# I Rinker (Maricopa plant) 

## I United Metro #41 

## 1 22.45 

## 1 35.83 

## 1 28.27

## 1 8.73

## 1 14.75

# 1 1997 ~lwne 

## I pm, 

# 1 GO 

# I ~aix 

# 1 voc SOX



# I Rinker (San Tan plant) 

## I United Metro#48 

## 1 22.73

## 1 51.68 

## 1 98.27

## 1 16.64

## 1 11.18

### ( 42.36

Dairv Nutrition



### I Monsanto 

### I Stoneville Seed 

### 1 34 

### 1 0.1 

### 1 0.4 

### 1 - 

### I 

### - I 

# I Triumph Thermal Processing 

## I AMTl 0.05

## 1 0.26

## 1 1.2 

## 1 0.03

# 1 94.11

2 

## 1 0.12

"-" = zero value or not applicable 

### ' = Sources with a name change between 1997 and 2006 -

Waste Management Inc. 

## I Sanifil -

TOTAL 

### 1 85.71 

### 1 107.55 

### 1 131.74 

### 1 47.47 

### 1 29.16 1.6 

## 1 - -Rinker submitted Non-Title

### V permit applicationsfor their two facilities (Maricopa and San Tan plants) to satisfy the requirements of GRIC's Non-Title 

### V permitting process. The information and emissiondata supplied in their permit applicationswas usedfor this 2007 El update. 

### 5.2. New Sources New point sources on the Community are those sources that were not operating in 1997 but were operating in2006. 

### A summary of the newsources and their associated emissions is presented in Table 5.4. 

### TABLE 5.4 ~ew' Point Source Emissions (tonslyr)

Cemex 

## I 12.4 

## 1 - 

## I - 

## I - 

## I Charnoion Homes Redman Homes 

### I - 

### I - 

### 1 - 

### I - 

### I

Hanson 

### I 3.5 

### 1 0.09 

### 1 0.37 

### 1 0.02 

### 1 1.33 Gila River Sand & Gravel - Maricopa Gila River Sand & Gravel

### - Santan 429.89 441.8

I I I I I Love's Travel Center Maricooa Readv Mix 0.04 0.04

- 1.04 

## 1 Superlite Block Triumph Engines

Fiveof the new sources listed inTable 5.4 submitted productiondata andlor emission data to satisfy the requirements of GRIC's permitting process. Additional information was collected by the CEM while conducting on-site visits and various methodologies were appliedto derivethe estimated emissions. The remainingfive sources were only operating for a short period of time toward the end of 2007 or have limited production or emission factor data available. Emissions from these five sourceswere not included in this update because GRlC is using data generated between 1997 and 2006 for the 2007 updated Emission Inventory. - - Triumph Precision Castings TOTAL

Emissions from the point sources were calculated using mass balance, material usage estimates and AP-42 emission factors. Several of the above-listed sources hired consultants or used in-house environmental personnel to develop their individual permit application with emission estimates. The permit applications were reviewed bythe GRlC CEMfor reasonableness, completenessand correct emission factors before includingthe emissions data in the permit applications into the 2007 El. Emission estimates for other sources were prepared by GRlC consultants using the information supplied in the permit applications. 0.21 0.21

"-" = zero value or not applicable 

### ' = Operating in 2006, but not in 1997 888.63 0.02 0.02 0.01 0.01



### - 0.17 - 0.79 

### - 0.06 1.35

### 5.3. Discontinued Sources A list of the discontinuedsources and their associated emissions is presented inTable 5.5. 

### TABLE 5.5 

### ~iscontinued' Point Source Emissions (tonslyr)

5.4. 

### Facilities Below Permitting And Reporting Thresholds 

### Source Arizona Processing Fertizona Coolidge Imageof Wicker Phillips Services Solkatronic 1 Air Products TOTAL

Several facilities are below the permitting thresholds or have equipment that is exempt from permitting. The permitting thresholds are identified in theAQMP and include, but are not limited to, facilities that emit one ton per year or less of any single regulated air pollutant; 1,000 pounds peryear or less of any singe HAP or one ton of any combinationof HAPs; or 

### 300 pounds per year or less of any single ultra-HAP or combination of ultraHAPs. These facilities are listed in Table 5.6. 

### TABLE 5.6 Facilities Below Permitting And Reporting ~hresholdsl "-" = zero value or not applicable 

### ' = Operat~ng In 1997 but not in 2006 PW~O 35 0.76

5.5
- 41.26 CO 0.16

- 0.16

souffie A & A Precast 

# I Acker Stone 

## I Lumber Products 

### Source Gila River Utility Authority Allison LLC (sublease to Lumber Products) Access Recovery 

### NOx 0.94

0.94

Iron City Rentals Lone Butte Trade Center ADESA Beaudry RV Environmental Stoneworks



### I Freightliner Sterlina Western Star of Arizona 

### I Verizon Wireless 

### I VOC 0.01 0.15

- 0.32 0.48

McNeil Brothers Monty Brother's Landscaping Peterson Transportation Factory Expo Home Center FerrellGas Fillmore Partnership 

# I Gila River Telecomm -

1 = One ton per year or less of any single regulated air pollutant; 1,000 pounds per year or less of any singe HAP or one ton of any combination of HAPs; or 300 pounds per year or less of any single ultra-HAP or combination of ultra-HAPS. SOX
-

Robert Ewing General Contractor Rock N Roll Trucking San Carlos Irrigation Proiect

### 6 AREA SOURCES Forthe purpose of this El update, area emissionsources include open burning, agricultural tillage and harvesting, residential fuel combustion, agricultural wind blown dust (nonanthropogenic) and agricultural nitrogen fertilizer usage (non-anthropogenic). Emissions from wildfires have not been calculated since wildfires rarely occur in the GRlC Sonoran Desert environment. Except for agricultural-related sources (e.g., tilling, harvesting, windblown dust, and fertilizer usage), the area sources have not changed significantly since 1997. Therefore, for non-agriculturalsources, the 1997 El emissions data was usedfor this 2007 El Update. For agricultural sources, the 1997 El indicates that 32,196 acres were in agl-icultural production. In2006, the most recentyear with available data, there were 35,065 acres in production (see Figure 3, attached). For both Eltimeframes (1997 and 2006), the major crops producedon the Gila River IndianCommunity included alfalfa, cotton,wheatlbarley, citrus, and vegetables. These crop types were used to estimate the emissions for the agricult~~ral sources in both the 1997 and 2007 Els. Therefore, the 8.9% increase in agricultural productionfrom 1997 to 2006 was applied to the 1997 emissions for tilling 

### & harvesting (448.1 

### I tpy PMlo), windblown dust (241 tpy PMI0), and fertilizer usage (45 tpy NOx) to estimate the emissions for this El. 

### A summary of the area source emissions for the 2007 El is presented in Table 6.1 below. 

### TABLE 6.1 Area Source Emissions (tonslyr)

"-" = zero value or not applicable Sottrctb Open Burning Agricultural Tilling & Harvesting Residential Fuel (gas) Combustion Residential Wood Combustion Agricultural Windblown Dust Nitrogen Fert~lizer Usage TOTAL 0.12 487.99

0.027 8.4 262.45
758.99 CO 1.2

0.33 61.4

- 62.93 VOC

0.026

55.9

-
55.93 1 

### : WQx

1.97

0.6

- 49 51.57 

### SOX

0.002 0.1

-
0.107 

### MOBILE SOURCES Mobile emission sources include nonroad vehicles and onroad vehicles. 7.1. 

### Nonroad Emissions from nonroad mobile sources result from combustion of fuels from mobile equipment otherthan onroad motorvehicles. These sources include recreational vehicles, construction equipment, lawn and garden equipment,farm equipment, marine vessels and locomotives. The majority of sources listed in this category will not be addressed in this section due to the lack of these activities within the boundaries of the Community. Emissions from marine vessels, recreational vehicles, lawn and garden equipment and construction activities are not addressed inthis inventory due to the lack of these activities during the 2006 calendar year. Emissions from locomotives are considered insignificant since only small rail sidings are present within the Community and rail trafic is almost nonexistent. Emissions from farm equipment are the only significant source of nonroad emissions within the Community. The ratio of 2006 to 1997 agricultural acreage was used to adjust the 1997 Eldata for the 2007 El Update (i.e. an increaseof 8.9%). The nonroademissions for the 2007 El Update is presented in Table 7.1 below. TABLE 7.1 

### Nonroad Mobile Source Emissions (tonslyr)

"-" = zero value or not applicable 

### Saume, Agricultural Tractor Operation

7.2. 

### Onroad This section explains the development of onroad niotor vehicle emissions estimates from vehicle trafficwithin the boundaries of GRIC. Vehicle trafficthroughthe Community by far represents the most predominant source of air pollution within the Community. The majority of the vehicle traffic can be attributed to Interstate 10 running between Phoenix and Tucson bisectingthe GRIC. PNIId 22 h#rx 28 WC 5 SOXA summary of the onroad emissions for the 2007 El Update is presented in Table 7.2. 

### TABLE 7.2 Onroad Mobile Source Emissions (tonslyr)

"-" = zero value or not applicable 

### 7.2.1. Data Collection Vehicle counts for roads maintained by the State of Arizona were supplied bytheArizona Department of Transportation (ADOT). MAG supplied a map listing vehicle counts over stretches of road maintained by the Maricopa County Department of Transportation (MCDOT). The GRlC Departmentof Transportationsupplied informationdocumentingthe total mileage of paved and dirtlgravel roads within the Community. A portion of these roads are maintained bythe Bureauof Indian Affairs and vehicle counts are not available. The total mileage of roads maintained by the State and County was subtracted from the total roads within the Community to revealthose roads without vehicle counts. Estimates of daily vehicle traffic were made for the portion of roads without vehicle counts. Daily Vehicle Miles Traveled (VMT) were calculated by multiplyingthe numbers of vehicles per day (vpd) by mileage information supplied bythe State, County and GRIC. A summary of the daily VMT for the five major road types is presented in Table 7.3 below. 

### TABLE 7.3 Onroad Mobile Source 

### VMT

VMT = Vehicle Miles Traveled per day Emission factors were obtained from EPA's Mobile6 model. MAG SI-~pplied GRlCwith the 2005 Mobile 6.2.03 input and output files usedto calculate emissionsfactors for their 2006 El. One set of output emissions factors included credit for implementation of the Area A (roughly MaricopaCounty) IM-240 vehicle emissions testing program. Thesefactors were applied to the daily VMT within Maricopa County. Another set of emissions factors wasgenerated for vehicles not required to pass the Maricopa County emissions testing program (IM-240) and these factors were applied to the daily VMT within Pinal County. 

### 7.2.2. Calculation Methods Criteria pollutant emissions for each vehicle classification traveling within each road type were calculated according to the following equation:


### Ex= 

### EFxx VMT, x VCP x 365 days 

# ( yr )x(45~6g)x(2~~lb) Where: Ex 

### = Criteria pollutant

### X emissions (i.e., PM10, CO, etc.) for a specific vehicle class EFx 

### = Emissionfactor for criteria pollutant 

### X from Mobile 6 VMT 

### = Dailyvel-~icle rr~iles traveled for roadtype

### Y (i.e., urban interstate, etc.) VCP 

### = Vehicle class percentage of total vehicles The resulting emissions for each vehicle classification were totaled to generate the total PMI0, CO, NOx, VOC and SOXemissions for each road type. PMIO err~issions from road dust generated by vehicle traffic on paved roads were calculated usingthe equation for paved roads listed inAP-42 Section 13.2.1 (Equation 1) and silt loading values from Maricopa County's 2005 El. Daily VMT were broken down to three categories with three different silt loading (sL) values: Interstates (sL 

### = 0.02 glm2); Roads with <5,000 VMTlday (sL 

### = 0.067 glm2);and Roads with >5,000 VMTlday (sL 

### = 0.23 glm2). The AP-42 equation for vehicles traveling on paved public roads is:

Where: EF = Particulate emissions factor (IbsNMT) k = Particle size multiplier for particulatesize range of interest (0.016 lbNMTfor PM10, AP-42 Table 13.2.1-1) sL = Road surface silt loading (glm2,Maricopa County 2005 El) W = Weight of vehicle (3 tons, Maricopa County 2005 El) C = Emission factor for 1980's vehicle exhaust, break & tire wear (0.00047 IbNMT,AP-42 Table 13.2.1-2)

### PMlO emissions from road dust generated by vehicle traffic on unpaved roads were calculated usingthe equationfor unpaved roads listed inAP-42 Section 13.2.2 (Equations I 

### b and 2), a silt loading value from Maricopa County's 2005 El, and daily VMT generated using bestavailable engineering estimates. Sincevehicletraffic on unpaved roads isvery limited within the Community, it was assumed that two vehicles per day traveled on each unpaved segment. The ruralportion of the Community has remained relatively unchanged since 1997;therefore, the lengthof unpaved roads from the 1997 Elwas usedfor the 2007 El Update (162.8 miles). The AP-42 equation for vehicles traveling on unpaved public roads is:

Where: EF 

### = Emission factor (IbsNMT) k 

### = Particle size multiplier (1.8 for PM10,AP-42 Table 13.2.2-2) s 

### = Silt content of road surface (11.9%, Maricopa County 2005 El) S 

### = Mean vehicle speed (25 mph, Maricopa County 2005 El) M 

### = Surface material moisture content (0.5%' Maricopa County 2005 El) C 

### = Emission factor for 1980'svehicle exhaust, break & 

### tirewear (0.00047 IbNMT,AP-42 Table 13.2.2-4) p 

### = #of dayslyrwith rainfall of at least 0.01 in. (31days, Western Regional Climate Center, Sacaton,AZ) 

### a 

### = for PMlO (1, AP-42 Table 13.2.2-4) 

### c = for PMlO (0.2, AP-42 Table 13.2.2-4) d = 

### for PMlO (0.5, AP-42 Table 13.2.2-4)

### 8 

### REFERENCES Arizona Department of TransportationWebsite. Vehicle Counts for Arizona Roads 2003 

### - 2006. Compilation of Air Pollution Emissions Factors AP-42, Fifth Edition, Volume 

### I Gila River lndian Community. 1997 Emissions lnventory for the Gila River lndian Community, dated October 1998. Gila River lndian Community Department of Transportation. List of Unpaved / 

### Paved Roads by District 

### -for Air Quality Program (memorandum dated March 4, 2005). Gila River lndian Community Department of Transportation. Traffic Count Data (memorandum dated April 7, 2004). Maricopa Association of Governments. Mobile 6 input and output files for 2005. Maricopa CountyAir Quality Department. 2005 Periodic Err~issions lnventoryfor PM10for the Maricopa County,Arizona, Nonattainment Area, dated May 2007. Maricopa County Department of TransportationWebsite. Traffic Counts for 1999 

### -2005.

### FIGURES([I 

# :

- ([I c


### . 

## - L