UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION IX
75 Hawthorne Street San Francisco, CA 94105



### Memorandum

To: Clark County PM 10 

### Maintenance Plan SIP Proposed Approval Doc ket, Docket ID EPA

R09

- OAR

- 2013

- 0735

From: Karina OConnor , Air Planning Office, EPA Region 9

Date: October 28 , 2013

RE: Adequacy D ocumentation for Plan M otor V ehicle Emission Budgets in August 2012

Clark County PM 10 

### Maintenance State Implementation Plan

Attached to this memorandum is the adequacy documentation for the M otor V ehicle Emission Budgets

in the Redesignation Request and Maintenance Plan for Particulate Matter (PM 10 

### ), Clark County,

Nevada (August 2012)(“ Clark County PM 10 

### Maintenance Plan ”)

.

The Clark County PM 10 

### Maintenance P lan was adopted by the Clark County Board of County

Commissioners on August 21, 2012 and submitted by the Nevada Division of Environmental Protection (NDEP) t o EPA on September 7 , 2012 . The Clark County PM 10 

### Maintenance Plan identifies MVEBs for

the BLM disposal area portion of the Las Vegas Valley nonattainment area for PM 10 

### for 2008, 2015 , and

2023 . W e announced receipt of the Clark County PM 10 

### Maintenance Plan on the Internet on November

7 , 201 2 , and reques ted public comment by December 7 , 201 2 . We did not receive any c omments on the budgets and Clark County PM 10 

### Maintenance Plan during the comment period.

This memo contains our analysis of the MVEBs in t he Clark County PM 10 

### Maintenance Plan for BLM dispos al area portion of the Las Vegas Valley PM 10 

### nonattainment area . The budgets are listed in the following table.

Budget Year PM 10 

### (t ons per design

day )

2008 141.40

2015 141.40

202 3 141.40

## Table 1. Evaluation of the Motor Vehi cle Emissions Budgets in the Clark County PM 10 

## Maintenance Plan (August 2012)

October 201 3 (reviewed by Karina O’Connor)

Adequacy Review Criteria (40 CFR part 93) Is Criterion

Satisfied? Reference in SIP Document/Comments

Sec. 93.118(e)(4)(i) The plan was endorsed by the

Governor (or designee) and was subject to a public hearing. Y The Clark County PM 10 Maintenance Plan was submitted to EPA on September 7,

2012 by the NDEP Administrator, the Governor of Nevada’s designee for all SIP

revision su bmittals. This SIP submittal documents that the Clark County Board of County Commissioners , which is responsible under Nevada law for implementation of air quality management programs within the boundaries of Clark County , held a p ublic hearing on the plan on August 21, 2012 , and adopted the plan on that same date.

Sec. 93.118(e)(4)(ii) The plan was developed through

consultation with federal, state and local agencies; full implementation plan documentation was provided and EPA’s stated concerns, if any,

were addressed. Y Clark County Department of Air Quality (DAQ) developed t he Clark County PM 10 Maintenance P lan in co nsultation from Federal, State, and local agencies. These agencies include: EPA Region IX; Federal Highway Administration; Nevada Departmen t of Transportation; Nevada Division of Environmental Protection, Bureau of Air Quality Planning; Regional Transportation Commission of Clark County; Public Works Departments of Clark County and the City of Las Vegas

. EPA submitted comments during the init ial comment period on the draft

maintenance plan, held from January 16 th through February 15 th , 2012. Issues raised by EPA Region IX staff on the draft PM 10 maintenance plan were discussed by Clark County DAQ and EPA in several meeting s and responded to by Clark County DAQ in the final adopted maintenance plan (see appendix B (“Documentation of the Public Review Process”) to the Clark County PM 10 Maintenance Plan)

.

Sec. 93.118(e)(4)(iii) The motor vehicle emission

budgets are clearly identified and precisely quantified. Y The MVEBs are clearly identified and pre cisely quantified for years 2008, 2015,

and 2023 in tables 7

- 1 and 7

- 3 of the Clark County PM 10 Maintenance Plan

. T he MVEBs for all three years are 141.41 tons per day. The info rmation in tables 7

- 1

and 7

- 3 show that the MVEBs represent the sum of certain emissions source categories included in the plan inventory, including vehicle (exhaust, brake wear, and tire wear), paved road dust, unpaved road dust, road construction, constr uction

track

- out, and wind erosion (road construction), plus a safety margin. Appendix A to the plan documents the methods and assumptions used to develop the emission inventory estimates used to develop the MVEBs.

## Table 1. Evaluation of the Motor Vehi cle Emissions Budgets in the Clark County PM 10 

## Maintenance Plan (August 2012)

October 201 3 (reviewed by Karina O’Connor)

Adequacy Review Criteria (40 CFR part 93) Is Criterion

Satisfied? Reference in SIP Document/Comments

Sec. 93.118(e)(4)(iv) The motor vehicle emissions

budget(s), when considered together with all other emission sources, is consistent with applicable requirements for reasonable further progress, attainment, or maintenance (whichever is relevant to a given implementation plan submission)

. Y The C lark County PM 10 Maintenance Plan describes how the MVEBs

, when

considered together with all other emission sources

, are consistent with

maintenance of the PM 10 NAAQS in Las Vegas Valley through 2023. The plan

uses a 2008 attainment

- year emissions invento ry to develop an emission inventory

and projects emissions to 2015 and 202 3 to show continually decreasing emissions

. When the safety margins are added to the motor

- vehicle and road

- construction

related emissions from the inventory, overall PM 10 emissions in 2015 (i.e., 694.35 tons per day) and 2023 ( i.e., 563.53 tons per day) would still be less than the 2008

attainment

- year inventory (i.e., 706.55 tons per day)

. See table 7

- 2 of the Clark County PM 10 Maintenance Plan. As such, inclusion of the identified safety margins as part of the MVEBs is consistent with continued maintenance of the standard in Las Vegas Valley.

## Table 1. Evaluation of the Motor Vehi cle Emissions Budgets in the Clark County PM 10 

## Maintenance Plan (August 2012)

October 201 3 (reviewed by Karina O’Connor)

Adequacy Review Criteria (40 CFR part 93) Is Criterion

Satisfied? Reference in SIP Document/Comments

Sec. 93.118(e)(4)(v) The plan shows a clear

relationship among the emissions budget(s), control measures and the total emissions inventory. Y Chapter 6 (“Maintenance Plan”) and appendix A (“Technical Support Document”)

to the Clark County PM 10 Maintenance Plan document the relationship among the MVEBs, control measures and total emissions inventory. Specifically, chapter 6 presents the overall emissions within the BLM disposal area in terms of point, nonpoint, on

- road, and nonroad emissions, and also includes certain emission

reduction credits (ERC). The MVEBs represent the sum of emissions estimates for certain motor vehicle related source categories, including vehicle (exhaust, tire wear and brake wear), paved and unpaved road dust, construction track

- out, and road construction (including wind erosion at road construction sites).

Documentation for the emissions estimates for each of the in divid ual source categories that, when added together with the safety margins , comprise the MVEBs

is found in the following chapters of appendix A: chapter 5 (“Fugitive Nonpoint Source Emissions”), including subsections 5.1.4.3 (“Road Construction”), 5.1.4.4 (“Construction Track

- Out”), and 5.1.4.5 (“Wind Erosion”)(particularly, table 5

- 20); subsection 5.3 (“Unpaved Roads”); and chapter 8 (“On

- Road Mobile

Emiss ions”)(includes vehicle exhaust, tire wear and brake wear, and PM 10 from vehicle entrainment over paved roads). Where applicable, these emissions estimates show the effect of control measures approved as part of the plan, particularly those related to fugi tive dust sources. T he sum of the estimates emissions from these source categories were then increased by safety margins

sufficient to result in MVEBs for 2008, 2015, and 2023 equal to a level of 141.41

t ons per day , which match es the existing attainment p lan budget for 2006.

## Table 1. Evaluation of the Motor Vehi cle Emissions Budgets in the Clark County PM 10 

## Maintenance Plan (August 2012)

October 201 3 (reviewed by Karina O’Connor)

Adequacy Review Criteria (40 CFR part 93) Is Criterion

Satisfied? Reference in SIP Document/Comments

Sec. 93.118(e)(4)(vi) Revisions to previously submitted

control strategy or maintenance plans explain and document any changes to any previous submitted budgets and control measures; impacts on point and area source emissions; any

ch anges to established safety margins (see §93.101 for definition), and reasons for the changes (including the basis for any changes to emission factors or

estimates of vehicle miles traveled). Y Clark County DAQ developed the Clark County PM 10 A ttainment P lan in 2001

which established MVEBs for the years 2001, 2003 and 2006. EPA determined that these budgets were adequate for conformity in January of 2002 and approved that plan in June of 2004

. See 69 FR 32273 (June 9, 2004). Clark County DAQ

used M OBILE 5B and PART5 to develop the motor vehicle emissions in th e 2001 attainment plan, but appropriately used EPA’s updated motor vehicle emissions factor model ( MOVES ) and the updated 2011 version of AP

- 42 to estimate motor

vehicle

- related emis sions for the PM 10 m aintenance plan. In addition, Clark County DAQ used updated VMT estimates for the later years (2008, 2015 and 2023) provided by the Regional Transportation Commission of Southern Nevada (RTC)

to develop the updated emissions estimates in the PM 10 maintenan ce plan. A safety margin was also allocated to the budgets established in the maintenance plan. The impact of all these changes result s in maintenance plan MVEBs that are equal to that of the 2006 attainment budget, 14 1 .41 t ons per day

.

Sec. 93.118(e)(5) EPA has reviewed the State’s

compilation of public comments and response to comments that are required to be submitted with any implementation plan. Y A notice of the initial public comment period was published in the Las Vegas

Review

- Journal and the Las Vegas Sun on January 15

, 2012. Notice for the public workshop was published on January 27, 2012. Notices were also published on the Clark County website. The only comment s Clark County DAQ received on the

draft maintenance plan were from EPA. T he public hearing itself took place on August 21, 2012 by the Clark County Board of County Commissioners (BCC) in Las Vegas , Nevada. At the public hearing, a comment er expressed support for the draft plan. No adverse comments were made at the public heari ng from members of the public. The PM 10 maintenance plan submittal includes a copy of EPA’s comments on the draft plan and Clark County DAQ’s response to those comments. See appendix B (“Documentation of the Public Review Process”) to the Clark County PM 10 Maintenance Plan.