# Redesignation Request and Maintenance

Plan for Particulate Matter (PM 10 

# )

Clark County, Nevada

August 201 2Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 ii APPROVED BY THE CLARK COUNTY BOARD OF COMMISSIONERS

Susan Brager , Chair

Steve Sisolak , Vice

- Chair Larry Brown

Tom Collins Chris Giunchigliani

Mary Beth Scow Lawrence Weekly

PREPARED BY

Clark County D epartment of Air Quality Planning DivisionRequest for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 iii EXECUTIVE SUMMARY

This Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 ) is a formal request by Clark County, through its Department of Air Quality

, to the U.S. Environmental Protection Agency (EPA) to redesignate the Clark County PM 10 nonattainment area to attainment

for the 19 87 24

- hour National Ambient Air Quality Standard (NAAQS). The plan summarizes the progress in attaining the PM 10 standard , demonstrates that all Clean Air Act and Clean Air Act Amendment requirements for attainment have been met, and presents a plan to assure

continued maintenance over the next 10 years.

In 1990

, EPA designated the Las Vegas Valley, Hydrographic Area 212 (HA 212) in Clark County

, as being in “moderate” nonattainment of the 24

- hour PM 10 NAAQS. In 1993

, EPA

reclassified HA 212 as a “serious” nonattainment area because Clark County could not demonstrate attainment by the required date of December 1994

.

In June 2001

, Clark County submitted a PM 10 State Implementation Plan (SIP) that met federal requirements for serious PM 10 nonattainment areas. The SIP demonstrated that the adoption and implementation of Best Available Control Measures for fugitive sources and continuation of controls for stationary sources would result in attainment of the 24

- hour NAAQS by December
31, 2006. Although the Act required the SIP demonstrate attainment of the PM 10 NAAQS no later than December 31, 2001, EPA granted Clark County a five

- year extension for the 24

- hour attainment date. Final EPA approval of the Clark County PM 10 SIP became effective in July

2004.

I n June 2007

, Clark County submitted the PM 10 Milestone Achievement Report

, prepared in

accordance with 40 CFR Part 52

. The report documents Clark County’s attainment of the 24

- hour PM 10 NAAQS by the applicable date of December 31, 2006

. In August 2010

, EPA published a determin ation of attainment for PM 10 for the Las Vegas Valley in the Federal Register

.

Following on that success, this maintenance plan provides a PM 10 attainment demonstration that

use s the most recently adopted planning vari ables , including those approved by the Regional Transportation Commission of Southern Nevada , which is the designated Metropolitan Planning Organization for the Las Vegas urban area. The plan also provides revised emission inventories

and motor vehicle emi ssions budgets.

After EPA approval, th is plan will become federally enforceable and will determine how Clark County will maintain the 19 87 PM 10 NAAQS through 2023. Once approved, the budgets in th is plan will be the projected budgets use d to determine tra nsportation conformity in future regional transportation plans.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 iv THIS PAGE INTENTIONALLY BLANKRequest for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 v TABLE OF CONTENTS

1.0 INTRODUCTION

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

1.1 Introduction

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

1.2 Characteri stics and Health Effects

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

1.3 National Ambient Air Quality Standards

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

1.4 History of Clark County Nonattainment Area

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

1.4.1 Nonattainment Area

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

1.5 Required Components of a Redesignation Request

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

1.5.1 Attainment of the PM 10 Standards

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

1.5.2 Approved Implementation Plan

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

1.5.3 Permanent and Enforceable Improvements in Air Quality

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

1.5.4 Requirements under Section 110 and Part D of the Clean Air Act

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

1.5.5 Approvable Maintenance Plan: Section 175(a) of the Clean Air Act

.......... 6

2.0 ATTAINMENT OF THE PM 10 STANDARD

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

2.1 Introduction

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

2.2 Monitoring Network

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

2.3 Design value

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

2.4 Monitoring Results and Attainment Demonstration

................................ ................ 5

2.5 Quality Assurance Program

................................ ................................ ..................... 5

3.0 STATE IMPLEMENTATION PLAN APPROVAL

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

3.1 Introduction

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

3.2 Previous Plan Approvals

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

4.0 PERMANENT AND ENFORC EABLE IMPROVEMENT I N AIR QUALITY

........ 1

4.1 Introduction

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

4.2 Economic Conditions

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

4.2.1 Population Trends

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

4.2.2 De velopment Patterns

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

4.3 Meteorological Conditions

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

4.4 Attainment and Maintenance Control Measures

................................ ...................... 5

4.4.1 Stationary Point and Nonpoint Source Regulations

................................ ..... 5

4.5 Additional Emission Reduction Control Measures

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

4.5.1 Regional Haze Rule

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

4.5.2 Transportation Conformity

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

4.5.3 Clark County Natural Events Action Plan

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

4.6 Air Quality Trend Analysis: Weight of Evidence

................................ .................... 7

5.0 REQUIREMENTS FROM SE CTION 110 AND PART D OF THE CLEAN AIR

ACT AMENDMENTS

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

5.1 Introduction

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

5.2 Section 110 Requirements

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

5.2.1 Section 110(a)(2)

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

5.2.2 Section 110(l)

................................ ................................ ............................... 2Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 vi 5.3 Part D Requirements

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

5.3.1 Section 172(c)

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

5.3.2 Section 176(c)

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

6.0 MAINTENANCE PLAN

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

6.1 Introd uction

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

6.1.1 Inventory Domain

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

6.2 Transportation Input Data

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

6. 3 Efficiency and Effectiveness Factors

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

6.4 Emission Inventory Type Categories

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

6.4.1 Point Sources

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

6.4.2 Nonpoint Sources

................................ ................................ ......................... 4

6.4.3 Mo bile Sources

................................ ................................ ............................ 4

6.4.4 Banked Emission Reduction Credits

................................ ........................... 5

6.5 Summary of Emission Inventories

................................ ................................ ........... 5

6.6 Maintenance Demonstration

................................ ................................ .................... 8

6. 7 Rollback Model

................................ ................................ ................................ ........ 9

6.8 Monitoring Network and Verification of Continued Attainment

.......................... 11

6.9 Contingency Measures

................................ ................................ ........................... 11

6.9.1 Potential Contingency Measures

................................ ................................ 11

6.9.2 Tracking and Triggering Mechanisms

................................ ....................... 12

6.9.3 Action Resulting from Trigger Activation

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

6.10 Subsequent Maintenance Plan Revisions

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

7.0 MOTOR VEHICLE EMISSI ONS BUDGETS

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

8.0 REFERENCES

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

APPENDICES

APPENDIX A: Technical Support Document

................................ ................................ .......... A

- 1

APPENDIX B: Documentation of the Public Review Process

................................ .................. B

- 1Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 vii LIST OF FIGURES

Figure 1

- 1

. Clark County PM 10 Nonattainment Area (HA 212).

................................ ................... 4 Figure 1

- 2

. BLM Disposal Area within HA 212.

................................ ................................ .......... 5

Fi gure 2

- 1

. Clark County PM 10 Monitoring Stations.

................................ ................................ ... 2 Figure 2

- 2

. Design Values for 1999

– 2010 (μg/m 3 ).

................................ ................................ ...... 4 Figure 4

- 1

. Wind Speeds (2001

– 2010).

................................ ................................ ......................... 4 Figure 4

- 2

. Precipitation (2001

– 2010).

................................ ................................ ......................... 4 Figure 4

- 3

. Actual and Log PM 10 Trend.

................................ ................................ ....................... 8 Figure 6

- 1

. Emission Distribution in 2008.

................................ ................................ ................... 7 Figure 6

- 2

. Emission Distribution in 2023.

................................ ................................ ................... 7 Figure 6

- 3

. Nonpoint Emissions in the BLM Disposal Area.

................................ ........................ 8 Figure 6

- 4

. Comparison of 2008, 2015, and 2023 PM 10 Emissi ons.

................................ ............. 9

LIST OF TABLES

Table 2

- 1

. Clark County PM 10 Monitoring Sites

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

Table 2

- 2

. Estimation of PM 10 Design Concentrations

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

Table 2

- 3

. Design Values for 2008

– 2010 (μg/m 3 )

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

Table 2

- 4

. Summary of Las Vegas Valley PM 10 Monitoring Data, 2008

- 2010

........................... 5

Table 4

- 1

. Clark County Population History (1990

- 2010)

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

Table 4

- 2

. Monthly Averages for Temperature and Rainfall (1937 to 2010)

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

Table 6

- 1

. Daily VMT Data Used to Develop Emission Inventories

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

Table 6

- 2. Summary of Total Daily PM 10 Emissions (tpd)

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

Table 7

- 1

. BLM Disposal Area PM 10 Mobile Source Emissions (tpd)

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

Table 7

- 2

. Revised Maintenance Demonstration

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

Table 7

- 3

. PM 10 MVEBs for the BLM Disposal Area (tpd)

................................ ......................... 3Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 viii ACRONYMS AND ABBREVIATIONS

Acronyms

AQR Clark County Air Quality Regulation AQS Air Quality System

BACM Best Available Control Measures

BCC Clark County Board of County Commissioners

BLM Bureau of Land Management

BMP best management practices

CAA Clean Air Act

CFR Code of Federal Regulations

EI emission inventory

EPA U.S. Environmen tal Protection Agency

ERC emission reduction credit

FR Federal Register

HA Hydrographic Area

MVEB motor vehicle emission budget NAAQS National Ambient Air Quality Standards

NDEP Nevada Division of Environmental Protection

NEAP Natural Events Action Plan

NRS Nevada Revised Statues

RTC Regional Transportation Commission of Southern Nevada

SIP state implementation plan

VMT v ehicle m iles t raveled

Abbreviations

mph miles per hour

PM 2.5 particulate matter less than 2.5 microns in mean aerodynamic diameter

P M 10 particulate matter less than 10 microns in mean aerodynamic diameter tpd tons per day μg/m 3 micrograms per cubic meter

μm micronsRequest for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 1 

### 1.0 INTRODUCTION

1.1 INTRODUCTION

Clark County, in coordination with the Nevada Division of Environmental Protection (NDEP), requests that the U.S. Environmental Protection Agency (EPA) redesignate the Clark County

nonattainment area

, Hydrographic Area (HA) 212, to attainment status for particulate matter less than 10 microns (μm) in diameter (PM 10 ) under the 19 87 PM 10 24

- hour National Ambient Air Quality Standard (NAAQS)

.

To complete t h is redesignation request and maintenance plan in accordance with EPA guidance, Clark County i nventoried emissions of PM 10 for the baseline year (2008) and projected those

emissions outward to 2015 and 202 3 . The inventories were adjusted to reflect federal , state , and

local rules on PM 10 emissions that have already been adopted or implemented. These controls

were shown to reduce overall PM 10 emissions through the maintenance year ( 202 3)

.

1.2 CHARACTERISTICS AND HEALTH EFFECTS

“Particulate matter” is a general term used to describe a complex group of airborne solid, liquid, and semi volatile materials of various sizes and compositions. Primary PM is emitted directly into the atmosphere from anthropogenic activities, such as agri cultural operations, industrial processes, construction and demolition activities, and entrainment of road dust into the air, and nonanthropogenic activities, such as windblown dust and ash from forest fires. Secondary PM is formed in the atmosphere from ( predominantly gaseous) combustion by

- product precursors, such as nitrogen oxides and volatile organic compounds. The overwhelming majority of airborne PM in Clark County is primary PM; the major source is fugitive windblown dust, with contributions

from en trained road dust and construction activities.

Particulate size is a critical characteristic of PM that primarily determines the location of its deposition along the respiratory system. EPA has established two types of PM air quality standards, one for P M 10 and one for PM 2.5 . (The latter refers to the subset of PM 10 with an aerodynamic diameter smaller than 2.5 μm.)

PM 10 has a detrimental effect on human health because it can accumulate in the respiratory system. Short

- term exposure can irritate the lung s and may cause immune system responses, resulting in lung constriction that produces shortness of breath and coughing. Larger particles deposit in the upper respiratory tract; smaller particles travel deep into the lungs and are retained longer.

Long

- ter m, low

- level PM 10 exposure may cause cancer and premature death. Those with a history of asthma or chronic lung disease are especially sensitive to these effects. The elderly or those with heart conditions may also have severe reactions, since the resultin g lack of oxygen may strain the heart.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 2 1.3 NATIONAL AMBIENT AIR QUALITY STANDARDS

O n July 1, 1987 , EPA revised the PM NAAQS (Volume 52, page 34634 of the Federal Reg i ster (52 FR 24634))

. T he previous standards addressed total suspended particulate s, without regard to
size ; t he revised standards address ed only particles having an aerodynamic diameter of 10 μ m or less. EPA determined that these microscopic particles can be inhaled deep into the lungs and present a hazard to public health when concentrations exceed certain levels. Both annual

averaged and 24

- hour averaged PM 10 standards were promulgated; however, EPA revoked the

annual

- averaged standard in 2006 (71 FR 61144). The current PM 10 ( primary) standard retains only the 24

- ho ur averaging time, at a level of 150 micrograms per cubic meter (μg/m 3 )

.

1.4 HISTORY OF CLARK COU NTY NONATTAINMENT AR EA

After passage of the 1990 Clean Air Act Amendments , EPA designated all areas previously classified as Group I areas as “moderate” nonattai nment areas, including HA 212 (CAA §107(d)(4)(B)). EPA required these moderate nonattainment areas to submit a state implementation plan (SIP) by November 1991 that would demonstrate attainment of the PM 10 NAAQS by December 1994. Because of unprecedented g rowth, high

- wind events, and other factors, Clark County could not demonstrate attainment by the required date, and EPA reclassified HA 212 as a “serious” nonattainment area on January 8, 1993 (58 FR 3334). In 1997,

a PM 10 SIP revision was submitted. In De cember 2000, the Clark County Board of County Commissioners (BCC) requested that the state formally withdraw all previously submitted SIPs and addenda because none demonstrated attainment of the NAAQS.

Section 110 of the Clean Air Act (CAA) requires that states not meeting the NAAQS submit a SIP detailing programs to bring the nonattainment area into attainment. After completing comprehensive research and work programs to address the problems identified in the 1997 PM 10 SIP revision, Clark County submitte d a new SIP to EPA in June 2001 that met federal requirements for remediating serious PM 10 nonattainment areas. This new SIP demonstrated that the adoption and implementation of Best Available Control Measures (BACM) for fugitive

sources and continuation o f controls for stationary sources would result in attainment of the annual average PM 10 NAAQS by 2001 and attainment of the 24

- hour NAAQS by December 31, 2006. Although the CAA required the SIP demonstrate attainment of the PM 10 NAAQS no later

than Decembe r 31, 2001, EPA granted Clark County a five

- year extension for the 24

- hour attainment date. Clark County supported its extension request with a Most Stringent Measure control analysis that showed the emission control programs proposed for the valley were a t least as stringent, if not more so, than control programs implemented in other nonattainment areas.

In June 2004, EPA published final approval of the PM 10 SIP (69 FR 32273). In June 2007, Clark County submitted a milestone achievement report that descri bed the county’s progress in implementing the SIP (DAQEM 2007a). In August 2010, EPA determined HA 212 had attained

the PM 10 NAAQS (75 FR 45485).

With submittal of this redesignation request and maintenance plan, Clark County is requesting

that EPA designate Clark County in attainment of the PM 10 NAAQS.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 3 1.4.1 Nonattainment Area

Figure 1

- 1 depicts the PM 10 nonattainment area established by EPA (HA 212), which is roughly 1,500 square miles, largely under federal control, and includes the :

**•** City of Las Vega s

**•** City of North Las Vegas

**•** City of Henderson

**•** Unincorporated urban areas of Clark County

**•** Desert National Wildlife Refuge lands

**•** Humboldt

- Toiyabe National Forest lands

**•** Red Rock Canyon National Conservation Area

**•** Nellis Air Force Base

**•** Nellis Bombing and Gunnery Range

**•** Nellis Small Arms Range

**•** Clark County Shooting Range

**•** Las Vegas Paiute Indian Reservation

**•** Spring Mountain State Park

**•** Lake Mead National Recreational Area

.

More than 80 percent of the land in Nevada is under federal jurisdiction, most of it managed by the Bureau of Land Management (BLM). In 1998, Congress passed the Southern Nevada Public Land Management Act, which allowed BLM to sell, trade, or lease public land within a specific area around Las Vegas. There was an amendment to this boundary in 2003, and minor adjustments thereafter. The area currently comprises 327,047 acres and is known as the BLM disposal area (Figure 1

- 2). Lands controlled by the federal government outside this area remain

in a native or managed state, and the disposal boundary can only be changed by an act of Congress.

Because t he BLM disposal area contains nearly all of the anthropogenic sources and sensitive

receptors within the nonattainment area, it was used for the attainment demonstration in the

EPA

- approved PM 10 S IP and in this maintenance plan.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 4 Figure 1

- 1

. Clark County PM 10 Nonattainment Area (HA 212).Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 5 Figure 1

- 2

. BLM Disposal Area within HA 212. ND Non Disposable

AreaRequest for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 6 1.5 REQUIRED COMPONENTS OF A REDESIGNATION R EQUEST

CAA Section 107(d)(3)(E) defines the five conditions that must be met before EPA can redesignate a nonattainment area to attainment. With the submittal of this plan

, Clark County

meets these five conditions.

1.5.1 Attainment of the PM 10 S tandards

Clark County must show that the area is attaining the applicable NAAQS. Redesignation of PM 10 nonattainment areas to attainment are based solely on ambient air quality data. Section 2 presents

the data used to demonstrate attainment.

1.5.2 Approved Implementation Plan

The SIP for the nonattainment area must be fully approved unde r CAA Section 110(k) and must satisfy all requirements that apply to the nonattainment area. Section 3 provides the information required by CAA Section 110(k) to show that Clark County has an approved PM 10 SIP.

1.5.3 Permanent and Enforceable Improvements in Ai r Quality

Clark County must be able to reasonably attribute improvement s in air quality to emission

reductions that are permanent and federally enforceable. Section 4 shows that improved air quality in the Clark County area is the result of permanent and enforceable emission reduction

control measures

, as opposed to air quality improvements resulting from adverse economic or meteorological conditions.

1.5.4 Requirements under Section 110 and Part D of the Clean Air Act

Clark County must meet all requirements of Section 110 and Part D that applied before submittal of the redesignation request. Section 5 discusses the noninterference of this SIP with any applicable requirements concerning attainment

, and with reasonable further progress towards

attain ment of all other criteria pollutant NAAQS or any other applicable CAA requirement.

1.5.5 Approvable Maintenance Plan : Section 175(a) of the Clean Air Act

Section 107(d)(3)(E) of the Clean Air Act Amendments stipulates that EPA must fully approve a

maintenan ce plan that meets the requirements of CAA Section 175(a) before it can redesignate

an area to attainment. Section 6 provides a plan to maintain the PM 10 NAAQS for at least 10 years after redesignation.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 1 

### 2.0 ATTAINMENT OF THE PM 10 

### STANDARD

2.1 INTRODUCTION

The first required component of an area’s redesignation request is a demonstration that it has attained the NAAQS. Th is attainment demonstration is based on quality

- assured monitoring data representative of the Clark County PM 10 nonattainment area . A total of three consecutive years

of non

- violating air quality data is needed to show attainment of the standard. A complete year of air quality data comprises all four calendar quarters, with each quarter containing data from at least 75 percent o f the scheduled sampling days.

Attainment of the PM 10 standard is demonstrated through establishment of a design value . As specified in Appendix K of Title 40, Part 50 of the Code of Federal Regulations (40 CFR 50),

attainment of the 24

- hour standard is d etermined by calculating the expected number of exceedances of the 150 μg/m 3 limit per year: the standard is attained when the expected number

of exceedances is one or less.

On August 3, 2010, EPA issued a final rule determining that the PM 10 NAAQS had b een attained for the HA 212 nonattainment area by the applicable attainment date of December 31, 2006, and that the area was currently attaining the standard (75 FR 45485). Therefore, the requirements of CAA Section 107(d)(3)(E) (i) have been satisfied.

2.2 M ONITORING NETWORK

40 CFR 58 defines the requirements for the ambient air quality monitoring programs mandated by the CAA. Clark County’s PM 10 monitoring network consists of eight State and Local Air Monitoring System monitors; the system is governed by q uality assurance and quality control procedures and subject to periodic EPA performance audits. As shown in Table 2

- 1, the monitoring objective of all but one station is “ population exposure .” The except ion is the Jean monitoring station, which monitors background concentrations.

Table 2

- 1

. Clark County PM 10 Monitoring Sites

Site Name Scale Monitoring Objective

Paul Meyer Middle Population exposure

Palo Verde Neighborhood Population exposure

Joe Neal Neighborhood Population exposure

Green Valley Middle Population exposure

Sunrise Acres Neighborhood Population exposure

Jean Regional Background

J.D. Smith Neighborhood Population exposure

Boulder City Neighborhood Population exposure

Figure 2

- 1 shows the locations of the Clark County PM 10 monitoring stations

. Table 2

- 2 show s the design value concentrations measured at these stations from 200 8

– 20 10.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 2 Figure 2

- 1

. Clark County PM 10 Monitoring Stations

.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 3 Table 2

- 2. Design Values for 2008

– 2010 ( μg/m 3 )

Site ID Site Name Number of Daily Va lues 1st High 2nd High 3rd High 4th High Site

Value Design Value (highest site value)

0020 E. Craig Road 876 123 102 98 96 98

98 0043 Paul Meyer 1,050 8 3 76 70 66 66

0072 Lone Mountain 806 70 69 59 58 59

0073 Palo Verde 1,060 57 54 52 51 51

0075 Joe Neal 1,047 120 96 95 84 84

0298 Green Valley 1,041 144 81 80 78 80

0561 Sunrise Acres 1,047 106 103 86 81 81

1021 Orr 804 85 75 71 70 71

2002 J.D. Smith 1,045 109 91 82 78 78

2.3 DESIGN VALUE

The design value (in μ g /m 3 ) is the concentration derived from a statistical approach to

monitor ing data that describes the air quality status of a given area , during a specific period, relative to the NAAQS. When a design value is related to a comprehensive emissions inventory (EI) for the same period, future concentrations can be predicted through emissions forecasts.

The 24

- hour PM 10 baseline year ( 2008 ) design value for the B LM disposal area was derived using the PM 10 SIP Development Guideline ( EPA 1987)

. Data from the nine PM 10 monitoring sites that operated from 2008

– 2010 were ranked by the four highest values for each site during

that period. As Table 2

- 3 shows , the first, second, third, or fourth highest value s are selected for

each site

, depending on the number of recorded values at that site during the three

- year period.

Table 2

- 3. Estimation of PM 10 Design Concentrations

The data analysis identified two exceptional events , one on February 13 , 2008, and another on May 21, 2008

. On these days, HA 212 experienced high

- wind events during which the 24

- hour

PM 10 standard was violated.

Sustained winds of 25 miles per hour ( mph ) and gusts of 40 mph are the established thresholds for exceptional high

- wind events in HA 212; w inds greater than these values overwhelm BACM. Wind speeds during both identified events were greater than these thresholds. Since PM 10 emissions were not reasonably controllable during these events, they were not reasonably Number of Daily Values Data Point Used for Design Concentration

≤ 347 Highest Value

348

– 695 Second Highest Value

696

– 1

, 042 Third Highest Value

1

, 043

– 1

, 096 Fourth Highest ValueRequest for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 4 preventable; the events were therefore flagged in EPA’s Air Quality System (AQS). In accordance with EPA’s Exceptional Event Rule, Clark County is requesting that the se exceedance days be excluded from regulatory consideration

.

T he two event days were not considered in the design value calculations. Clark County ranked the remaining high values from each site for the three

- year period (Table 2

- 2). The highest value from the list, 98 μ g /m 3 , was determined to be the design value. The design day (i.e ., the day on which the design value concentration occurred) was determined to be April 15, 2008.

Figure 2

- 2 shows the 12

- year trend of the design values in HA 212. The data demonstrate a significant improvement in air quality since implementation of the PM 10 SIP.

Figure 2

- 2

. Design Values for 1999

– 2010 (μg/m 3 ).Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 5 2.4 MONITORING RESULTS A ND ATTAINMENT DEMONS TRATION

The monitoring data illustrated by Figure 2

- 2 verify that the Clark County nonattainment area

has been in attainment with the PM 10 NAAQS since 2006, in accordance with the requirements

of 40 CFR 58. Table 2

- 4 outlines the highest 24

- hour concentrations during 2008

– 10, excluding

the two high

- wind events of February 13, 2008, and May 21, 2008.

Tab le 2

- 2

. Summary of Las Vegas Valley PM 10 Monitoring Data, 2008

– 2010

Site ID Monitoring Site Highest 24

- hour PM 10 Concentration (μg/m 3 ) Expected Exceedances Per

Year

2008 2009 2010 2008

- 2010

0020 E. Craig Road 123 67 N/A 1 0

0043 Paul Meyer 76 83 48 0

0072 Lone Mountain 70 69 N/A 1 0

0073 Palo Verde 54 57 49 0

0075 Joe Neal 120 95 64 0

0298 Green Valley 144 81 52 0

0561 Sunrise Acres 106 85 57 0

1021 Orr 71 85 N/A 1 0

2002 J. D. Smith 109 77 62 0

1 Site is no longer in operation or no longer monitoring PM 10

.

Since none of the values are greater than the PM 10 NAAQS

, the expected number of exceedances

in the Las Vegas Valley for 2008

– 2010 is zero . This is lower than the annual expected

exceedance rate for the 24

- hour PM 10 NAAQS, demonstrating continued attainment of the

standard.

2.5 QUALITY ASSURANCE PR OGRAM

PM 10 data have been collected and verified in accordance with 40 CFR 58 and the Quality Control & Assurance System for Continuous Particulate M atter (2.5 & 10) Pollutants (Quality Assurance Project Plan) (DAQEM 2008). PM 10 audit data are submitted to AQS, and the audit

schedule is available in the annual network plan Clark County submits to EPA

.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 1 

### 3.0 STATE IMPLEMENTATION PLAN AP PROVAL

3.1 INTRODUCTION

The second required component of an area’s redesignation request is a fully approved SIP

satisf ying all requirements that apply to the nonattainment area under CAA Section 110(k)

, which addresses completeness findings, deadlines for EPA actions, types of EPA actions, and sanctions that may be applied to areas failing to meet CAA requirements. The information in this section demonstrates, as required under CAA Section 110(k), that there i s an approved SIP for the Clark County PM 10 nonattainment area.

3.2 PREVIOUS PLAN APPROV ALS

In June 2001, Clark County submitted a PM 10 SIP that met federal requirements for remediating

serious PM 10 nonattainment areas. This SIP demonstrated that the adoption and implementation of best available control measures and technologies would result in attainment of the 24

- hour NAAQS by December 31, 2006. Final EPA approval of the Clark County PM 10 SIP was ef fective in July 2004 (69 FR 32273).Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 1 

### 4.0 PERMANENT AND ENFORC EABLE IMPROVEMENT IN AIR QUALITY

4.1 INTRODUCTION

The third required component of a redesignation request is a demonstration that improvement s in air quality are reasonably attributed to emission reductions that are permanent and federally enforceable. The information in this section shows that improved air quality in the Clark County

PM 10 nonattainment area is the result of permanent and enforceable emission reduction control

measures
, as opposed to adverse economic or meteorological conditions.

4.2 ECONOMIC CONDITIONS

Clark County, formed in 1909 and located at the southern tip of Nevada, is an area of more than 8,000 square miles. Most county residents live within the BLM disposal area , a 511

- square

- mile

basin inside HA 212

. The BLM disposal area was one of the fastest

- growing area s in the nation for several decades, and hosts up to 40 million visitors each year. R apid population growth , high construction activity, disturbance of vacant lands, and high

- wind events led to increased PM 10 24

- hour NAAQS exceedances in the 1990s and early 2000s.

4.2.1 Population Trends

More than 96 percent of Clark County’s population resides in HA 212, and more than 99 percent of the population in HA 212 resides within the BLM disposal area . Table 4

- 1 provides population data for Clark County over the last 20 years; during that time, the average annual population growth was 4.8 percent.

Table 4

- 1

. Clark County Population History (1990

- 2010)

Year Clark County HA 212 BLM Disposal

Area Annual Population Change in HA 212 Annual Percent I ncrease

1990 805,519 776,180 773,029

— —

1991 829,839 797,973 794,779 21,793 2.8%

1992 870,692 837,862 834,604 39,889 5.0%

1993 919,388 884,184 880,874 46,322 5.5%

1994 986,152 949,139 945,784 64,955 7.3%

1995 1,048,668 1,009,812 1,006,467 60,673 6.4%

1996 1,119,708 1,077,971 1,074,597 68,159 6.7%

1997 1,170,113 1,127,419 1,124,161 49,448 4.6%

1998 1,246,193 1,199,347 1,196,164 71,928 6.4%

1999 1,321,176 1,272,638 1,269,290 73,291 6.1%

2000 1,428,689 1,372,022 1,367,181 99,384 7.8%

2001 1,498,278 1,448,827 1,445,970 76,805 5.6%

2002 1,578,332 1,525,226 1,522,291 76,399 5.3%

2003 1,641,529 1,586,032 1,583,363 60,806 4.0%

2004 1,747,025 1,691,647 1,685,391 105,615 6.7%

2005 1,815,700 1,759,636 1,752,457 67,989 4.0%Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 2

Year Clark County HA 212 BLM Disposal

Area Annual Population Change in HA 212 Annual Percent I ncrease

2006 1,912,654 1,855,019 1,847,643 95,383 5.4%

2007 1,996,542 1,933,602 1,925,411 78,583 4.2%

2008 1,986,145 1,924,817 1,916,585

- 8,785

- 0.5%

2009 2,006,347 1,943,812 1,936,450 18,995 1.0%

2010 2,036,358 1,974,611 1,966,074 30,798 1.6%

Source: Clark County Department of Comprehensive Planning

.

4.2.2 Development Patterns

More than 90 percent of the land of HA 212 is owned by federal agencies . The land is managed with varying types and intensities of use, according to individual agencies’ land and resource management plans

. BLM has the largest holding , including the Red Rock National Conservation Area west of Las Vegas. Most of the Spring Mountain Range , including Mt. Charleston, is administered by the U.S. Forest Service as part of the Humboldt

- Toiyabe National Forest. The rapid disturbance and development of vacant land has been concentrated in the BLM disposal area, which includes the cities of Las Vegas, Henderson, and North Las Vegas, as well as the unincorporated areas of Clark County.

Monitored levels of PM 10 have shown a continued decline since the early 2000s despite the rapid growth. It is reasonable, therefore, to conclude that improvements in HA 212 PM 10 air quality have not been caused by a downturn in economic conditions, i.e., any reduction of PM 10 concentrations in HA 212 can be reasonably attributed to the emission reduction control

measures in the PM 10 SIP, which are permanent and federally enforceable.

4.3 METEOROLOGICAL CONDI TIONS

Summers in Clark County display the classic characteristics of the desert Southwest: daily high temperatures in the lower elevations often exceed 100oF, with lows above 70oF. The s ummer heat is usually tempered by low relative humidity, which may increase for several weeks during July and August in association with moist monsoonal wind flows from the south. This is the most common period for thunderstorms in the valley, which can re sult in high

- wind events. Temperatures during the spring and fall are generally moderate , with strong winds being the most persistent weather hazard

.

Winters are generally mild and pleasant. Afternoon temperatures average 60oF, and the sky is normally cle ar and sunny. Snow accumulation on valley floors is rare; however, higher elevations, such as the Spring Mountains, typically receive 5

– 10 feet of snowfall annually. Based on measurements from McCarran International Airport over the past 30 years, temperat ures fall below 32oF an average of 24 days a year

.

Average annual rainfall in the valley, also measured at McCarran, is approximately 4.16 inches.

Table 4

- 2 lists temperature and rainfall averages in Clark County over the last seven decades.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 3 Table 4

- 2

. Monthly Averages for Temperature and Rainfall (1937 to 2010)

Month Maximum ( **°** F) Minimum ( **°** F) Average ( **°** F) Rainfall (inches)

January 57.1 34.5 47.0 0.52

February 62.5 38.9 52.2 0.58

March 69.5 44.3 58.3 0.45

April 78.2 51.7 66.0 0.20

May 88.5 61.1 75.4 0.15

June 98.6 69.9 85.6 0.07

July 104.6 76.5 91.2 0.43

August 102.2 74.8 89.3 0.44

September 94.7 66.6 81.3 0.32

October 81.3 54.3 68.7 0.25

November 66.5 42.0 55.0 0.36

December 57.2 34.7 47.0 0.40

Annual Average 80.1 54.1 68.1 4.16

Source: DRI ( 201 0)

.

Elevated levels of PM 10 emissions in HA 212 are largely associated with wind

- blown dust, re

entrained road dust, or construction emissions , and are often amplified by dry, arid conditions.

H igh

- wind events in HA 212 generally occur between February

– May and September

– December, although high winds have been recorded in other months as storms pass through. The monitoring

stations that record the highest concentrations of PM 10 d uring high

- wind events are typically

those located near large expanses of disturbed soil.

Figures 4

- 1 and 4

- 2 illustrate data on wind speed and precipitation, respectively, in HA 212 for the last 10 years. Rainfall dropped significantly during this time (2006

– 2009), although winds remained relatively constant. SIP

- implemented PM 10 control measures were effective in spite of drought

- like conditions, so it is reasonable to assume that lower PM 10 concentrations over the last 10 years were not caused by atypi cal meteorological conditions.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 4 Figure 4

- 1

. Wind Speeds (2001

– 2010)

.

Figure 4

- 2 . Precipitation (2001

– 2010)

.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 5 4.4 ATTAINMENT AND MAINT ENANCE CONTROL MEASU RES

CAA Section 110(a)(2)(A) requires that each SIP include enforceable emission limitations and other control measures to achieve and maintain the NAAQS

. As part of its attainment effort

, Clark County included the Section 90 series of the Clark County Air Qua lity Regulations ( AQR s) in the PM 10 SIP . These rules include control requirements for open areas, construction

activities

, and vacant lands , and their implementation and enforcement have significantly contributed to the improvement of air quality in the Las Vegas Valley

.

Clark County is now obligated to maintain the valley’s improved air quality status. Clark County is not proposing amendments to the Section 90

- series AQRs with this maintenance plan; in fact,

the Section 90 series is vital to maintainin g compliance with the PM 10 NAAQS. Construction activities and vacant lands are the two source categories with the highest PM 10 emissions; while their controls are not without cost, Clark County cannot relax PM 10 measures applicable to HA

212 at this time. Section 110(l) of the CAA states: “[EPA] shall not approve a revision of a plan if the revision would interfere with any applicable requirement concerning attainment and reasonable further progress....”

4.4.1 Stationary Point and Nonpoint Source Regulations

PM 10 stationary point sources in Clark County are generally industrial and utility combustion sources that emit 70 tons per year or more. Nonpoint sources are commercial, small

- scale industrial, and residential sources whose emissions fall below point sour ce reporting levels and which are too numerous or too small to identify individually.

Clark County has numerous SIP and non

- SIP regulations in place for stationary and nonpoint sources, notably AQR Sections 12.0

– 12.13 and Section 21. Clark County also enf orces several federal regulations as part of its emissions control program, including 40 CFR 61 and 63, “National Emissions Standards for Hazardous Air Pollutants” (under AQR Section 13) and 40 CFR 60, “Standards of Performance for New Stationary Sources” (under AQR Section 14).

As part of its 2001 PM 10 SIP submittal, Clark County adopted comprehensive fugitive dust controls (the Section 90 series). The following list outlines these AQRs:

**•** Section 90 requires stabilization of open areas and vacant lands to prevent entrainment of particulate matter.

**•** Section 91 requires stabilization of unpaved roads, and paving of unpaved roads when traffic volume is equal to or greater than 150 vehicles per day. It also prohibits construction of new unpaved roads in publ ic thoroughfares.

**•** Section 92 requires stabilization of unpaved parking areas, including material handling and storage yards, and generally prohibits construction of new unpaved parking lots in

the nonattainment area.

**•** Section 93 sets forth requirements fo r paved roads, street sweeping equipment, and

certain other dust

- mitigating devices.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 6 **•** Section 94 establishes permitting and dust control requirements for construction activities. This regulation incorporates by reference a comprehensive dust control

handbo ok (DAQEM 2003) that outlines Best Management Practices (BMP) for

construction activities.

The Clark County dust program met EPA’s most stringent measures requirements at the time of adoption, and it remains state

- of

- the

- art because of Clark County’s SIP commitment to evaluate the feasibility of revising the Section 90 rules. This resulted in numerous amendment adoptions

in 2002 and 2003.

4.5 ADDITIONAL EMISSION REDUCTION CONTROL ME ASURES

4.5.1 Regional Haze Rule

Th is rule

, promulgated in July 1999

, mandates emission reductions to achieve natural visibility levels in mandatory Class I areas by 2064. C ontrol measures principally address light

- scattering

and

- absorbing aerosols. Several of these measures will be implemented throughout the western

state s , i.e., Best Available Retrofit Technolog y will be installed on older emissions units

. The

measures will be operati onal by January 1, 2015

, or no later than five years after approval of state regional haze SIPs, whichever comes first. Most western states, including Nevada, have submitted regional haze SIPs ; EPA proposed full approval of Nevada’s plan on June 22, 2011 (76 FR 36450).

4.5.2 Transportation Conformity

Clark County will continue to work closely with the Regional Transpor tation Commission of Southern Nevada ( RTC ) to assure that regional transportation plans and transportation improvement programs in HA 212 are consistent with and conform to Clark County ’s air quality

program requirements , including the PM 10 SIP.

4.5.3 Clark Co unty N atural E vents A ction P lan

In April 2005, the BCC adopted the Natural Events Action Plan for High

- Wind Events : Clark County , Nevada (NEAP)

. The NEAP protects public health by warning of impending wind

events : dust control permittees are reminded to employ all BMP for dust control, t he public is

notified of wind events in progress, and Clark County citizens are educated on the health hazards

of PM

. Public notifications include information on how residents can reduce airborne particulates by avoiding c ertain individual or collective particulate

- emitting activities , especially during high

- wind events

.

Protection of public health is the principal goal of the NEAP, which contains detailed information about actions implemented in Clark County to minimize public exposure to potentially high levels of PM 10 caused by winds. Its primary components are:

**•** A high

- wind event notification system that includes an early warning procedure.

**•** Education and outreach programs.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 7 **•** Enhanced enforcement and compliance program s to reduce emissions.

**•** Submittal of required documentation to EPA in the event of an exceedance.

The only guidance in effect when Clark County developed its NEAP was a n EPA policy mem o, “Areas Affected by PM 10 Natural Events” (EPA 1996), which allowed ai r quality data to be flagged so it would not count toward an area’s attainment status if it could be shown there was a clear causal relationship between the data and one of three categories of natural events: volcanic and seismic activity, unwanted wild la nd fires, or high

- wind events. On March 22, 2007, EPA promulgated a final rule (72 FR 13560) addressing the review and handling of air quality monitoring data influenced by “ exceptional events ,” i.e., those for which the normal planning and regulatory proc ess established by the CAA is not appropriate.

Clark County ’s NEAP procedures have been very effective since their adoption, and changes reflecting the exceptional event final rule have created an even stronger program. Clark County now provides more information to EPA in submittal package s, and has improved early w arning processes to better inform the public.

Clark County continually updates its natural events program. One example is the high

- wind exceptional event exercise drill, which is conducted each year before the windy season to refamiliarize staff with pro cedures and identify potential problem areas. Additionally, construction notices are issued that proactively warn sources of winds that are below NEAP event levels but could still impact public health . These and other enhancements provide essential

tools f or regularly evaluating operational processes to help reduce the health and environmental

effects of PM on county residents.

4.6 AIR QUALITY TREND AN ALYSIS : WEIGHT OF EVIDENCE

Clark County performed an air quality trend analysis for the period between 2001 and 2010 using quality

- assured data from EPA ’s AQS database (Figure 4

- 2). The purpose was to use a weight

- of

- evidence approach to support the attainment demonstration of the PM 10 NAAQS

.

For the demonstration, a regressed logarithmic trend line was fit to the data points in lieu of a

linear trend line because of its smoothing effect on the rate of change of the dependent variable ( PM 10 design values, or y ), and because the trend line is mo re representative of real world conditions (i.e., the line is prevented from dropping below zero (the lower asymptote) due to all

values of y > 0).

The R

- squared (R 2 ) of the regression

— commonly called the “ goodness

- of

- fit ”

— is the percentage

of variance i n y that can be accounted for by the independent variable (years, or x ). An R 2 greater than 0.80 suggests that the regression line equation ( y = 62.32ln( x ) + 255.24) strongly approximates the data points, and provides a significant level of credibility for the weight

- of

evidence attainment demonstration

. The R 2 of this regression is 0.9366.

Clark County i s confident that future PM 10 concentrations will continue to trend downward with

the maintenance control mea sures described in Section 4.4 and continued e nforcement of the

PM 10 control program.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 8 Figure 4

- 3

. Actual and Log PM 10 Trend

.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 1 

### 5.0 REQUIREMENTS FROM SECTION 110 AND PART D OF THE

CLEAN AIR ACT AMENDM ENTS

5.1 INTRODUCTION

The fourth required component of a redesignation request is verification that Clark County meets CAA Section 110 and Part D requirements. This section provides that verification

.

5.2 SECTION 110 REQUIREM ENTS

Before EPA can redesignate the Clark County PM 10 n onattainment area, the provisions of CAA

Section s 110(a)(2) and 110(l) must be satisfied. Section 110(a)(2) addresses the general requirements for SIPs ; Section 110(l) prevents approval of SIP revisions if components of the plan would interfere with any ap plicable requirement concerning attainment

, with reasonable further progress towards attainment of a NAAQS

, or with any other applicable CAA requirement.

5.2.1 Section 110(a)(2)

This CAA section contains the following SIP requirements:

1. Establishment and impl ementation of enforceable emission limitations

.

2. Monitoring, compilation, and analysis of ambient air quality data

.

3. Preconstruction review and permitting of new and modified major stationary sources

.

4. Consultation with, and provisions for

, the participation of affected local governments

.

5. Assurance the state has adequate funds and authority to enforce the SIP and associated regulations

.

6. Establishment of permit fees for stationary sources.

Nevada Revised Statutes ( NRS ) 445B.500 addresses the establishment, admi nistration, and enforcement of programs for controlling air pollution in Nevada . In Clark County, these programs are administered and enforced by the Clark County Department of Air Quality . The department has more than 100 staff members and an annual budge t of approximately $28 million

to administer , implement, and enforce the CAA

, including the development of air quality plans and regulations applicable to the PM 10 maintenance area.

Clark County ’s current air quality program meets all the provisions required by Section 110(a)(2). If Clark County be comes unable to meet any of the se provisions, NRS 445B.520 and 445B.530 allow the State Environmental Commission to assume jurisdiction over the local air quality management program to ensure that CAA requirements are met . EPA also has authority to impose sanctions on a state if it “finds that any requirement of an approved plan (or approved part of a plan) is not being implemented” (CAA, Section 179).Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 2 5.2.2 Section 110(l)

CAA Section 110(l) requires th at SIP revision s not interfere with requirements for attainment or reasonable further progress regarding other criteria pollutants, or with any other CAA requirements. Since this plan proposes no changes to current emission reductions control

measures, it poses no interference with Clark County’s progress towards continued attainment of

the carbon monoxide or ozone NAAQS. The only other criteria pollutant in Clark County is

PM 2.5 , for which Nevada is currently designated as attainment/unclassifiable under C AA Section 107(d).

5.3 PART D REQUIREMENTS

Sections 172(c) and 176(c) in Part D of the CAA lay out requirements that apply to all areas designated as nonattainment because of a NAAQS violation.

5.3.1 Section 172(c)

This CAA section contains general requirement s for maintenance plans

, including:

1. I mplementation of reasonabl y available control measures, including reasonably available control technologies, for existing sources

.

2. Reasonable further progress for existing sources

.

3. A current EI

, and periodic EIs every three years until attainment

.

4. I dentification and quantification of allowable emissions for new and modified stationary

sources

.

5. A s tationary source permitting program

.

6. Other measures, including enforceable emission limitations, additional control measures, and a schedule for compliance

.

7. Compliance with Section 110 provisions

.

8. Contingency measures.

Clark County ’s current air program, in conjunction with the components of this plan, meets all Section 172(c) provisions

.

5.3.2 Section 176(c)

This section contains transportation and general conformity provisions applicable in maintenance areas. The transportation conformity process ensures transportation plans, programs, and projects in maintenance areas do not create new violations of the NAAQS, do not increase the frequency or severity of NAAQS violations, and do not delay timely attainment of the NAAQS. It does notRequest for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 3 allow federal agencies to engage in , support, or provide financial assistance for licensing, permitting, or approving any project unless the project conforms to the SIP.


### 6.0 MAINTENANCE PLAN

6.1 INTRODUCTION

The fifth required component of an area’s redesignation request is the fulfillment of CAA Section 107(d)(3)(E) requirements. These specify that for an area to be redes ignated to attainment, EPA must approve a maintenance plan that meets all the conditions of CAA Section 175(a), including a comprehensive and accurate demonstration of continued maintenance of the

PM 10 NAAQS for 10 years after redesignation.

Two approach es are acceptable for demonstrat ing maintenance of the NAAQS ( EPA 1992). The

first

, the emissions projections approach

, compares a projected EI with a n attainment EI. The

second is a complex analysis using gridded dispersion modeling

. Clark County chose th e emissions projection approach

, compar ing an EI for the baseline year (2008) to an EI for the maintenance year (202 3 ). The maintenance year was chosen to allow EPA 18 months after receipt of a complete submittal to process Clark County’s redesignation req uest.

The baseline EI represents an emission level that would not cause a NAAQS violation

— the design value concentration of 98 μg/m 3 on the design day of April 15, 2008. If the projected maintenance year concentration remains at or below the baseline yea r concentration , continued

maintenance is demonstrated. In addition

, the maintenance demonstration includes a comparison between an interim year (2015) concentration and the baseline year concentration to show

maintenance throughout the 10

- year period after redesignation, not just in the maintenance year.

A roll

- forward model was also used to support the attainment demonstration

6.1.1 Inventory Domain

Although EPA requires an EI for the entire nonattainment area, attainment can be demonstrated for a larger or smaller area if there are compelling reasons to do so. Use of smaller areas can focus the attainment analysis on relevant areas and key anthropogenic sources that affect hig h

concentration monitors and population areas.

In choosing a domain boundary, such factors as wind patterns and source, monitor, and receptor locations (e.g., population centers) should be considered (EPA 1991). The boundary should be

established such th at phenomena at the boundary have little effect on the center. Background concentrations should account for sources not explicitly modeled (40 CFR 51, App. W; EPA 1987, Appendix D; and EPA 1981, p.27.)

Based on these criteria, and consistent with the boun dary used in the PM 10 SIP attainment demonstration, Clark County selected the BLM disposal area as the domain for the maintenance

demonstration. Its edges are areas of low emission density that have little effect on the places of concern (i.e., locations w ith high monitored values)

. Sources in the outlying areas are effectively accounted for by including background concentrations in the inventory. This approach isRequest for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 2 supported by modeling work conducted in Clark County for previous studies (e.g., DRI 1997 )

tha t discovered sources of PM 10 have a small radius of influence.

HA 212 covers roughly 960,000 acres , o ver half of which are under federal control :

**•** Bureau of Reclamation : 9,689 acres

**•** Desert National Wildlife Refuge : 226,728 acres

**•** Lake Mead National Recreational Area : 1,148 acres

**•** Nellis Air Force Base and Ranges : 25,124 acres

**•** Red Rock Canyon National Conservation Area : 195,780 acres

**•** Humboldt

- Toiyabe National Forest : 60,073 acres.

N onattainment area EIs were not projected for future years because Cla rk County based the attainment demonstration on the BLM disposal area

. The demonstration w as limited to this area for several reasons, including:

**•** All violations of the 24

- hour NAAQS happened within the BLM disposal area

.

**•** More than 99 percent of the popula tion in the nonattainment area lives within the BLM disposal area

.

**•** More than 98 percent of the vehicle miles traveled (VMT) in the nonattainment area are within the BLM disposal area

.

**•** The topography within the BLM disposal area is relatively uniform, a fac tor that minimizes modeling uncertainty, whereas the outlying areas of the nonattainment area

vary by over 8,000 feet

– a factor that increases modeling uncertainty.

**•** All man

- made emissions of PM 10 , except one major stationary source and small

percentages o f minor sources, unpaved road dust , and paved road dust

, lie within the BLM disposal area

.

**•** Focusing on the BLM disposal area places a greater emphasis on sources closest to human receptors.

Before Clark County attained the PM 10 NAAQS, all measured violations occurred within the BLM disposal area , which is also where nearly all anthropogenic emissions within the nonattainment area occur. As part of a network saturation study (DAQEM 2007b), three samplers were deployed outside the BLM disposal area bu t within the nonattainment area. No

violations were recorded.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 3 6.2 TRANSPORTATION INPUT DATA

Table 6

- 1 summarizes the transportation data ( i.e., daily VMT) used to develop the EIs in

Section 6.4 ( RTC 2008). All other input data used in developing the EIs, such as vehicle fleet mix, seasonal/day

- of

- the

- week adjustment factors, and hourly activity profiles, have been updated with the most current data available.

Table 6

- 1

. Daily VMT Data Used to Develop Emission Inventories

Year VMT (HA 212) VMT (BLM Disposal Area)

Baseline (2008) 39,377,980 38,795,925

I nterim (2015) 48,886,838 48,073,477

M aintenance (2023) 63,994,191 62,735,685

6.3 EFFICIENCY AND EFFECTIVENESS FACTOR S

Control efficiency, rule effectiveness

, and rule penetration factors were applied to the baseline

emissions o f point and nonpoint source categories affected by the AQRs , when applicable

. The

term “ control efficiency ” includes capture efficiency for point sources

, which defines the percentage of emissions from a source captured by a control device

. Rule effectiveness reflects

the actual capability of a regulatory program to achieve the emission reductions required by

r egulation. Rule penetration is the assumed percentage of emissions of the targeted Source

Classification Code subject to the requirements of a rule.

6.4 EMISSION INVENTORY T YPE CATEGORIES

The PM 10 EIs w ere derived from estimates developed for categories including point sources, nonpoint sources, mobile, and banked emission reduction credits (ERCs) . T he following sections briefly discuss each categor y and its estimated emissions; more detailed explanation s of the

estimates are provided in the technical su pport document (Appendix A)

.

6.4.1 Point Sources

Clark County’s point source inventory i ncludes all airport/aircraft and Title V stationary source s inside HA 212, as well as minor stationary sources clustered together closely enough to be considered potential hot spots of emissions within the BLM disposal area.

Clark County has authority over most emission units in the county; however, Nevada state law places certain electric steam

- generating units in the county under NDEP jurisdiction . The

f

acilities within the nonattainment area over which NDEP has or had authority, partial or whole,

are:

**•** NV Energy Clark Station

. The emission units at this facility that once operated under NDEP’s jurisdiction have been decommissioned . However, emission units under Clark

Cou nty ’s jurisdiction still operate at this facility.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 4 **•** NV Energy Sunrise Station

The status of all units at these facilities, w hether decommissioned or in current operation, was properly considered in the point source EIs. . C ertain emission units at this facility operate under NDEP’s jurisdiction

, while others operate under Clark County’ s jurisdiction.

All point source EIs for the baseline year ( 2008 ) were obtained from reports submitted by the

indi vidual sources, and reflect actual emissions for that calendar year. This information was

q uality a ssured /q uality c ontrolled by Clark County staff.

Projections were performed for 2015 and 2023 for each facility (except Nellis Air Force Base) using the 2008 EI and Economic Growth Analysis System, version 5.0, Source Classification Code growth factors, which are based on the Regional Economic Models, In c. 6.0 model. Projections for Nellis were estimated using actual 2008 emissions and projections supplied by

the source.

Linear regression was used to establish emissions projections for 2015 and 2023. To account for the possibility of a new power plant o r expansions of existing plants, emissions from a theoretical power facility were included for the 2015 and 2023 EIs.

6.4.2 Nonpoint Sources

Nonpoint sources of emissions are those that fall below point

- source reporting levels and are too

numerous or small to identify individually. Generally, they are small

- scale industrial or residential operations that use emission

- generating materials or processes.

Nonpoint source emission calculations are estimated as countywide totals rather than as

individual source em issions. W ith some exceptions, these emissions are calculated by multipl ying an EPA

- approved factor (emissions per unit of activity) by the appropriate activity or activity surrogate responsible for generating emissions. When available, actual activity dat a is

used ; when data is unavailable, surrogates are used

, including county population or employment data by industry type (and, when applicable, by growth factors from the Economic Growth Analysis System)

.

6.4.3 Mobile Sources

The mobile sources category con sists of on

- road and non

- road sources and locomotives. On

- road

mobile sources consist of cars , trucks, motorcycles, and other motor vehicles traveling on public roadways . Emissions from this category are vehicle exhaust, brake wear, and tire wear, all

calc ulated using the MOVES2010a model. Re

- entrained road dust from on

- road sources, while included in the mobile source budgets for transportation conformity, is addressed in the nonpoint sector of this plan. Re

- entrained road dust emissions for on

- road emissi ons were calculated using the January 2011 version of AP

- 42.

Non

- road mobile sources consist of a wide variety of equipment types that either move under their own power or can be moved from site to site . Exhaust emissions were calculated usingRequest for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 5 EPA’s NONRO AD model. Re

- entrained unpaved road dust, while included in the mobile source budgets, is addressed in the nonpoint portion of this plan.

The third and last subcategory is locomotives, whose emissions were categorized separately from the nonpoint source i nventory.

6.4.4 Banked Emission Reduction Credits

If a source voluntarily reduces emissions beyond the permit limits, and/or implements controls beyond what is required, it may apply for ERCs pursuant to Section 12.7. If the ERCs are approved, they will be ban ked for future use or transacted in accordance with the AQRs. Clark County may grant reciprocity for use of ERCs banked by NDEP within the county if the ERCs comply with all AQR requirements at the time of redemption, and NDEP has the authority to

grant re ciprocity for use of Clark County

- banked ERCs at sources in Clark County that it permits. NDEP has jurisdiction over permitting, compliance, and ERC banking for sources in the county that burn fossil fuels in a boiler to produce steam for the production of electricity ( NRS

445B.500 ); all other emission units in the county are under the jurisdiction of Clark County

.

Clark County chose to account for all ERCs in the maintenance year ( 202 3) because ERCs can be used in nonattainment areas to offset emissions of new major sources and major modifications at existing major sources

. ERC emissions are accounted for in the point source emissions growth

estimated for 2023 because point source emissi ons growth and ERCs largely overlap. To be conservative, however, Clark County is not considering the potential overlap in this

demonstration

.

6.5 SUMMARY OF EMISSION INVENTORIES

Table 6

- 2 summarizes the 2008, 2015

, and 202 3 PM 10 EIs for the BLM disposal area in tons per day (tpd) for five source categories. In particular, emissions from wind erosion of vacant lands show a significant decrease over time as construction within the BLM disposal area consumes

vacant lands.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 6 Table 6

- 2

. Summary of Total Daily PM 10 Emissions (tpd)

Source 2008 (t pd ) 2015 (t pd ) 2023 (t pd )

Point Emissions:

Subtotal: 2.19 2.60 2.88

Nonpoint Emissions:

Fuel Combustion 1.23 1.29 1.38

Residential Wood Combustion 1.89 1.90 1.92

Locomotive 0.06 0.06 0.06

Paved Road 30.85 38.04 48.78

Unpaved Road 5.84 6.51 7.49

Commercial Cooking 2.19 2.52 2.83

Mineral Processing (concrete, gypsum) 0.28 0.34 0.40

Mineral Processing (stone) 0.15 0.18 0.21

Asphalt 0.33 0.37 0.40

Wind Erosion (Construction) 183.97 217.70 249.21

Construction 30.93 37.69 41.22

Sand & Gravel 0.42 0.51 0.60

Open Burning 0.02 0.02 0.02

Wind Erosion (Vacant Lands) 439.05 288.16 122.77

Structural Fires 0.02 0.02 0.03

Vehicle Fires 0.03 0.03 0.04

Subtotal: 697.23 595.34 477.36

On

- road Emissions:

Subtotal: 3.08 2.52 2.75

Nonroad Emissions:

Subtotal: 3.74 2.95 1.94

Emission Reduction Credits:

Subtotal: 0.31 0.31 0.31

Total: 706.55 603.72 485.24

Figures 6

- 1 and 6

- 2 show emission distributions in 2008 and 2023, respectively, and Figure 6

- 3 shows the nonpoint source category EIs for each of the three demonstration years. Appendix A provides detailed information on the methodologies used to estimate EIs.

In s ummary, total PM 10 emissions decrease 31 percent (221 tpd) between 2008 and 2023.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 7 Figure 6

- 1

. Emission Distribution in 2008

.

Figure 6

- 2

. Emission Distribution in 2023

.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 8 Figure 6

- 3

. Nonpoint Emissions in the BLM Disposal Area.

6.6 MAINTENANCE DEMONSTR ATION

CAA Section 175(a) requires each request for redesignation to be accompanied by a SIP revisio n that provides for maintenance of the NAAQS for at least 10 years after redesignation. EPA ( 1992) recommends using the ratio of baseline emissions to the design value, adjusted for background concentration, to determine whether projected emissions for a f uture year will predict concentrations in compliance with the NAAQS.

Table 6

- 2 and Figure 6

- 4 show that projected future

- year PM 10 emissions are less than 2008

emissions. Since projected emissions for 2015 and 2023 are less than 2008 emissions, maintenance of the NAAQS is demons trated.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 9 Figure 6

- 4

. Comparison of 2008, 2015, and 2023 PM 10 Emissions

.

The EIs show a downward trend in PM 10 emissions, mainly due to the control measures

described in Section 4.4. N o emission increases are expected that will threaten the demonstration

of attainment ; even if new sources emerge, the 2023 EI is well below the 2008 EI

.

6.7 ROLLBACK MODEL

EPA recommends a combination of re ceptor and dispersion models

, paired with reliable emission projections

, to model attainment in a future year. However, receptor models cannot quantify absolute PM 10 emission estimates in some circumstances, such as urban locations where a large fraction of particulate emissions come from nontraditional sources (e.g., construction operations or wind

- blown fugitive dust). Dispersion models also have limitations that make modeling fugitive dust difficult, since uncertainties regarding emission rates, deposition rates, and plume characteristics of course fraction crustal particulates pose problems in obtaining valid

results

.

For these reasons, Clark County adopted the proportional rollback model approach to

demon strate attainment in the PM 10 SIP . Since it was an accurate predictor, the same approach

was used to demonstrate continuous (maintenance) attainment for 2015 and 2023.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 10 The rollback model assumes a linear relationship between PM 10 emissions from sources an d their

contribution to measured PM 10 levels in ambient air : for example, if 25 percent of emissions in

an area come from wind erosion of vacant land s
, the model assume s that 25 percent of the ambient concentration measured by a monitor in that area (minus the background concentration,

which remains constant) came from th is wind

- entrained so il. The proportional rollback model

assumes that any reduction or increase in emissions will cause a corresponding reduction or

increase in the ambient concentration mea sured at the monitoring station

. The basic steps are:

1. Determine the representative monitoring station(s) and design value.

2. Define the background concentration as the lowest PM 10 value recorded at an upwind
monitoring station on the same day or during the same time period.

3. Estimate the anticipated increase or decrease in emissions from each source.

4. Apply the same percentage of increase or decrease from emissions to the design

concentration

.

5. Calculate the anticipated ambient concentration after the emissions change.

The PM 10 SIP analyzed five microscale sites

, in addition to completing a valley

- wide analysis

. Since the a reas surrounding th os e five sites are now built out, they are no longer considered

repres entative . Moreover, as the PM 10 SIP stated, the percent reduction for attainment was equal or higher valley

- wide than at the microscale sites. The rollback analysis for this maintenance plan therefore uses a valley

- wide scale.

The analysis used a design value of 98 **μ** g/m 3

, minus the bac kground concentration of 37 **μ** g/m 3

measured at Jean on the design day ( April 15, 2008) . The Jean monitoring station is upwind of

the nonattainment area , so it is often used to represent background levels in Clark County.

The referenced design

- day and futu re

- year emission calculations do not include contribution s from the secondary formation of particulates , and the rollback method does not account for nonlinear secondary particulate formation. T he PM 10 SIP accounted for this by add ing 3.5 **μ** g/m 3

to the back ground concentration, based on past chemical mass balance studies . Including 3.5

**μ** g/m 3 to represent secondary PM, the background level was 40.5 **μ** g/m 3 . S ubtracting th is background level from the design value yielded a concentration due to anthropogenic emis sions

of 57.5 **μ** g/m 3 (98 **μ** g/m 3

– 40.5 **μ** g/m 3 ).

The following PM 10 concentrations are anticipated in 2015 and 2023.

**•** Future year 2015:

– Total 2008 emissions = 706.55 tpd (Table 6

- 2)

– Total 2015 emissions = 603.72 tpd (Table 6

- 2)

– Total 2008 anthropogenic concentration = 57.5 **μ** g/m 3Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 11 – Anthropogenic concentrations for 2015

, determined by multiplying the 2008 anthr opogenic concentration by the ratio of 2015 emissions to 2008 emissions :
57.5 **μ** g/m 3 • (603.72 tpd / 706.55 tpd) = 49.13 **μ** g /m 3

– Adding back the background concentration, which is presumed constant :
49.13 **μ** g/m 3 + 40.5 **μ** g/m 3 = 89.63 **μ** g/m 3

**•** F uture year 2023:

– Emissions = 485.24 tpd (Table 6

- 2)

– Concentration = (57.5 **μ** g/m 3 • (485.24 tpd / 706.55 tpd)) + 40.5 **μ** g/m 3 = 79.99 **μ** g/m 3

The concentrations predicted by the rollback analysis show that the 24

- hour PM 10 NAAQS will be maintained through 2023.

6.8 MONITORING NETWORK A ND VERIFICATION OF C ONTINUED

ATTAINMENT

After being redesignated to attainment status, Clark County will continue to operate its air quality monitoring network to verify attainment of the PM 10 NAAQS. Annual review of the eight State and Local Air Monitoring System monitors will be conducted in accordance with 40 CFR 58.20(d) to ensure the system continues to meet mon itoring objectives

.

6.9 CONTINGENCY MEASURES

CAA Section 175A(d) requires that a maintenance plan contain contingency provisions to assure prompt correction of any violation of the NAAQS. Contingency plans must also describe the

methods that will be used to ensure the measures in the plan are adopted quickly if triggered.

EPA (1992) states that a contingency plan does not have to contain fully adopted contingency

measures, but should at least have three primary elements:

1. A list of potential co ntingency measu res.

2. An explanation of the tracking and triggering mechanisms t hat will determine when contingency measures are needed.

3. A description of the process for recommending and implementing contingency measures

, with specific timelines for action.

6.9.1 Potential Conti ngency Measures

Clark County proposes the following potential control measures as part of this maintenance plan:

**•** Implementing a n ew dust control permit requirement for certain short

- term activities that disturb, or have the potential to disturb, soils that emit PM into the atmosphere, such asRequest for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 12 mechanized weed abatement, fairs, carnivals, Christmas tree and Halloween pumpkin lots, art sales, and similar activities

.

**•** Conducting a c omprehensive review an d update of the Construction Activities Dust

Control Handbook (DAQEM 2003) to i ncrease the effectiveness of existing BMP and to identify and develop new BMP. Updated BMP may include management practices for

soil

- disturbing activities not covered in current practices. Potential new BMP include practices for roadway and detention basin maintenance activities.

**•** Review ing the dust mitigation plan requirements in AQR Section 90

, giving consideration to reducing the acreage

- trigger thresholds and incorporati ng add itional mitigation plan criteria. Also reviewing Section 92, giving consideration to lowering applicability thresholds for unpaved parking lots.

**•** Reassign ing staff to provide additional field enforcement of the AQRs that control sources of fugitive dust emi ssions

.

**•** Mapping construction activities during inspections to collect PM 10 data to provide greater accuracy for calculating actual emissions from construction projects.

**•** Developing a new dust control database that will strengthen oversight of dust control

p ermits and improve source compliance.

**•** Amending current fugitive dust regulations to incorporate new technologies and measures for controlling emissions and preventing them from crossing property lines or causing a

nuisance.

Clark County may use additional strategies to address any future violations in the most appropriate and effective manner.

6.9.2 Tracking and Triggering Mechanisms

The primary tracking mechanism will be Clark County ’s continuous PM 10 monitoring network ( Section 6 .9). Clark Coun ty will examine ambient air quality monitoring data within 30 days of

collection to determine if the PM 10 NAAQS has been exceeded

.

The primary trigger mechanism will be a confirmed violation of the PM 10 NAAQS , defined as more than one exceedance day per year averaged over a three

- year period. The trigger date will be 60 days from the date a monitoring station records a reading that results in a design value equal to or greater than the PM 10 NAAQS

.

The triggering of the contingency plan would not automat ically require a revision of the PM 10 SIP, nor would Clark County necessarily be redesignated to nonattainment. Instead, it would

have a period of time to correct the violation by implementing one or more contingency

measures. I f violations continue d after contingency measures were implemented, additional

measures would be implemented until the violations were corrected.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 13 The RTC ’ s ongoing regional transportation planning process will serve as another means of tracking mobile source emissions , since the RT C revises its transportation improvement plan every three years and these revisions are subject to a transportation conformity finding

. Th at process will serve as a periodic check on maintaining the VMT and mobile source emissions projections in this plan.

6.9.3 Action Resulting from Trigger Activation

Within 45 days of the trigger date, Clark County must notify EPA that an internal review process

will be gin to evaluate potential contingency measures. Within 90 days of that notification

, Clark County must send EPA an information report outlining recommended actions. Clark County will then solicit stakeholder involvement through public forums (e. g.
, PM 10 working groups) to refine the process of implementing the recommended actions. The BCC and/or Nevada State

Env ironmental Commission will hold one or more public hearing s to consider the recommended contingency measures, along with any other s that may address the confirmed violation. The

necessary measures must be adopted and implemented within 18 months of submitt al of the information report to EPA.

6.10 SUBSEQUENT MAINTENAN CE PLAN REVISIONS

Section 175A(b) requires that

, eight years after redesignation of any area to attainment under Section 107(d), the state shall submit an additional revision of the applicable SIP that shows how the NAAQS will be maintained for 10 years after the expiration of the first 10

- year period. Clark County commits to the submit tal of a revised maintenance plan eight years after HA 212 is redesignated to attainment.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 1 

### 7.0 MOTO R VEHICLE EMISSIONS BUDGETS

Under CAA Section 176(c), transportation plans, programs, and projects in maintenance areas

that are funded or approved under Title 23 of the U.S. Code or the Federal Transit Act must

conform to the on

- road motor vehicle emissi ons budgets ( MVEBs ) specified in the applicable SIP. In this case, 40 CFR 93.118 provides the criteria and procedures for MVEBs.

The MVEB establishes a cap on motor vehicle

- related emissions that cannot be exceeded by predicted transportation system emis sions. The emissions budget applies a ceiling on emissions in the year for which it is defined

, and for all subsequent years until a different budget is defined for another year or a SIP revision modifies the budget. Table 7

- 1 lists 2008, 2015, and 2023

PM 10 mobile source emissions for the BLM disposal area.

Table 7

- 1

. BLM D isposal Area PM 10 Mobile Source Emissions (tpd)

Source 2008 2015 2023

Paved road 30.85 38.04 48.78

Unpaved road (public) 0.28 0.32 0.36

Vehicle (exhaust, brake wear, and tire wear) 3.08 2.52 2.75

Road construction 1.54 1.87 2.05

Construction track

- out 0.25 0.30 0.33

Wind erosion ( road construction) 6.53 7.73 8.85

TOTAL 42.53 50.78 63.12

EPA's conformity regulation (40 CFR 93.124) allows a SIP to quantify explicitly the amount by which motor vehicle emissions could be higher while still demonstrating compliance with the maintenance requirement. The plan can then allocate some or all of thi s additional “ safety margin ” to the emissions budgets for transportation conformity purposes. T he safety margin for this maintenance plan is 52 μg/m 3 , the difference between the NAAQS value (150 μg/m 3 ) and the design value (98 μg/m 3 ). Using the methodology of Section 6. 7 , the MVEBs were recalculated to include a safety margin.

The mobile source budgets for 2008, 2015, and 2023 (Table 7

- 1) were adjusted to 141.41 tpd, which match the emission budgets in the PM 10 SIP and were thus approved by EPA in 2004 (69 FR 32273). Clark County ’s request for the same PM 10 budget figure is both for consistency and for RTC’s familiarity with it in transportation planning. The mobile source budgets in Table 7

- 1

were increased by 98.88 tpd, 90.63 tpd, and 78.29 tpd for 2008, 2015 and 20 23

, respectively.

Table 7

- 2 lists the adjusted emission inventories for 2008, 2015, and 2023 based on the mobile budget increases.

The design values were recalculated using the rollback model. T hese parameters were used to recalculate the estimated concentrations for 2008, 2015, and 2023

. The revised maintenance demonstration for 2008, 2015, and 2023 still shows maintenance of the PM 10 standard: it

estimates maximum PM 10 concentrations of 106 μg/ m 3 in 2008, 97 μg/m 3 in 2015, and 86 μg/m 3

in 2023

.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 2 **•** Adjusted 2008 data:

– Pre

- adjusted total 2008 emissions = 706.55 tpd (Table 6

- 2)

– Desired mobile source emissions budget = 141.41 tpd

– Pre

- adjusted 2008 mobile source emissions budget = 42.53 (Table 7

- 1)

– Since total 2008 emissions include the pre

- adjusted 2008 mobile budgets, the latter are subtracted from the total and then the desired budgets are added: 706.55 tpd

- 42.53 tpd + 141.41 tpd = 805.43 tpd (adjusted 2008 EI)

– To determine the adjusted 2008 de sign value:

o Pre

- adjusted anthropogenic 2008 concentration = 57.5 μg/m 3 (Section 6.7)

o Pre

- adjusted total 2008 EI = 706.55 tpd (Table 6

- 2)

o Adjusted 2008 EI = 805.43 tpd

o Background concentration = 40.5 μg/ m 3 (Section 6.7)

o To determine the adjusted 2008 anthropogenic concentration, the pre

- adjusted 2008 anthropogenic concentration is multiplied by the ratio of the adjusted 2008 emissions to the pre

- adjusted 2008 emissions:

57.5 μg/m 3 • (805.43 tpd / 706.55 tpd) = 65.5 μg/m 3

o Because the background concentration, which is constant, is not accounted for in this anthropogenic concentration, it is now added to determine the adjusted 2008 design concentration: 65.5 μg/m 3 + 40.5 μg/ m 3 = 106 μg/m 3

**•** Adjusted 2015 data:

– Pre

- adjusted total 2015 emissions = 603.72 tpd (Table 6

- 2)

– Desired mobile source emissions budget = 141.41 tpd

– Pre

- adjusted 2015 mobile source emissions budget = 50.78 (Table 7

- 1)

– In that the total 2015 emissions include the pre

- adjusted 2015 mobile budgets, the

latte r are subtracted from the total and then the desired budgets are added: 603.72 tpd

– 50.78 tpd + 141.41 tpd = 694.35 tpd (adjusted 2015 EI)

– To determine the adjusted 2015 concentration:

o Pre

- adjusted anthropogenic 2008 concentration = 57.5 μg/m 3 (Section 6

- 7)

o Adjusted 2015 EI = 694.35 tpdRequest for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 3 o Pre

- adjusted total 2008 emissions = 706.55 tpd (Table 6

- 2)

o Background concentration = 40.5 μg/ m 3 (Section 6

- 7)

o The pre

- adjusted 2008 anthropogenic concentration is multiplied by the ratio of the adjusted 2015 emissions to the pre

- adjusted 2008 emissions = 57.5 μg/m 3 • (694.35 tpd / 706.55 tpd) = 56.5 μg/m 3

o Because the background concentration, which is constant, is not accounted for in this anthropogenic concentration, it is now added to determine the adjusted 2015 design concentration = 56.5 μg/m 3 + 40.5 μg/m 3 = 97 μg/m 3

**•** Likewise, the adjusted 2023 data is calculated as:

– Adjusted 2023 EI = 485.24 tpd

– 63.12 tpd +141.41 tpd = 563.53 tpd

– Adjusted 2015 anthropogenic concentration: (98 μg/m 3

– 40.5 μg/m 3 ) • (563.53 tpd / 706.55 tpd) = 45.9 μg/m 3

– Adjusted 2023 design concentration = 45.9 μg/m 3 + 40.5 μg/m 3 = 86 μg/m 3

Table 7

- 2

. Revised Maintenance Demonstration

Parameter 2008 2015 2023

Concentration before a djustment ( μg/m 3 ) 98 89.63 79.99

Background ( μg/m 3 ) 40.5 40.5 40.5

EI (tpd) 706.55 603.72 485.24

Mobile emissions (tpd) 42.53 50.78 63.12

Adjusted EI (tpd) 805. 43 694. 35 563. 53

Estimated concentrations after adjustment (μg/m 3 ) 106 97 86

Upon an EPA affirmative adequacy finding and approval of the MVEBs, the budgets in Table 7

- 3 will be used for conformity determinations in future regional transportation plans.

Table 7

- 3

. PM 10 MVEBs for the BLM Disposal Area (tpd)

Year 2008 2015 2023

Original 42.53 50.78 63.12

Adjustment + 98.88 + 90.63 + 78.29

MVEB 141.41 141.41 141.41Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 1 

### 8.0 REFERENCES

AQR Section 91. Fugitive Dust from Unpaved Roads, Unpaved Alleys, and Unpaved Easement

Roads (amended 7/1/2004).

40 CFR 50. National Primary and Secondary Ambient Air Quality Standards.

40 CFR 51. Requirements for Preparation, Adoption, and Submittal of Implementation Plans.

40 CFR 58. Ambient Air Quality Surveillance.

40 CFR 60. Standards of Performance for New Stationary Sources.

40 CFR 93. Determining Conformity of Federal Actions to State or Federal Implementation

Plans.

70 FR 20665. Clean Air Fine Particle Implementation Rule.

70 FR 71612. Final Rule t o Implement the 8

- Hour Ozone National Ambient Air Quality Sta ndard

- Phase 2; Final Rule t o Implement Certain Aspects of the 1990 Amendments Relating to New Source Review and Prevention of Significant Deterioration as They Apply in Carbon M onoxide, Particulate Matter and Oz one NAAQS; Final Rule for Reformulated Gasoline.

75 FR 45485. Determination of Attainment for PM 10 for the Las Vegas Valley Nonattainment
Area, NV

.

43 U.S.C. § 932. Mining Act of 1866 (repealed 1976).

43 U.S.C. § 1701

. Federal Land Policy and Management Act of 1976.

49 U.S.C. § 63. Federal Transit Act.

CBER . 2010. “Historical Economic Data for Metropolitan Las Vegas.” Las Vegas, Nevada: Un iversity of Nevada, Las Vegas. http://cber.unlv.edu/snoutlk.html

DAQEM. 2001. PM 10 State Implementation Plan for Clark Co unty. Las Vegas, Nevada : Clark County Department of Air Quality.

DAQEM

. 2003. Construction Activities Dust Control Handbook

. Las Vegas, Nevada: Clark County Department of Air Quality.

DAQEM. 2005. Natural Events Action Plan for High

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DAQEM. 2007 a

. PM 10 State Implementation Plan Miles tone Achievement Report. Las Vegas,

Nevada : Clark County Department of Air Quality.Request for Redesignation and Maintenance Plan for Particulate Matter (PM 10 )

August 2012 2 DAQEM. 2007b. Particulate Matter (PM 10 ) Saturation Monitoring Study . Las Vegas, Nevada: Clark County Department of Air Quality.

DRI. 1997. Fugitive Dust and Other Source Contributions to PM 10 in Nevada’s Las Vegas Va lley

. DRI Document No. 4039.2F1

. Las Vegas, Nevada: Desert Research Institute.

DRI . 2010. “Western Regional Climate Center Historical Climate Information.”

www.wrcc.dri.edu/CLIMATEDATA.html

EPA. 1981. “ Overview of Receptor Model Application to Particulate Source Apportionment .”

Vol. I of Receptor Model Technical Series

. EPA

- 450

- 4

- 81

- 016a. Washington, D.C.: U.S. Env ironmental Protection Agency.

EPA. 198 7. PM 10 SIP Development Guideline. EPA

- 450/2

- 86

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EPA. 1991. “ Guideline for Regulatory Applica tion of the Urban Airshed Model.” EPA

- 450/4

- 91

- 013

. Washington, D.C.: U.S. Environmental Protection Agency.

EPA. 1992. “Procedures for Processing Requests to Redesignate Areas to Attainment.” Memo , J. Calcagni to EPA Regional Division Directors, dtd

. 9/4/ 9 2. http://www.epa.gov /ttn/oarpg/t5/memoranda/redesignmem090492.pdf

EPA. 1996. “ Areas Affected by PM 10 Natural Events .” Memo, M. Nichols to distribution, dtd.

5/30/96. http://www.epa.gov/ttn/caaa/t1/memoranda/nepol.pdf

EPA

. 2006

. “Unpaved Roads.” Section 13.2.2 of Vol. I

, “ Stationary Point and Area Sources, ” of

AP

- 42, Compilation of Air Pollutant Emission Factors

. 5th e d

. Washington, D.C.: U.S. Env ironmental Protection Agency.

EPA. 2008. “ Ambient Air Monitoring Program. ” Vol. II of Quality Assurance Handbook for Air Pollution Measurement Systems

. EPA

- 454/B

- 08

- 003

. Washington, D.C.: U.S. Environmental Protection Agency.

EQM. 2006

. An Inventory of Vacant Land Soil Stability and Unpaved Private Roads in the Las Vegas Valley Using Remote Sensing Imagery

. Las Vegas, Nevada: Clark County Department of Air Quality.

RTC. 2008. “Travel Demand Model Methodology and Air Quality Conformity Analysis.” A ppendix 4 of Regional Transportation Plan 2009

- 2030 . Las Vegas, Nevada: Regional Transport ation Commission of Southern Nevada.