42258 Federal Register / Vol. 79, No. 139 / Monday, July 21, 2014 / Proposed Rules 

Designated representative means any 

Coast Guard commissioned, warrant, or 

petty officer who has been authorized 

by the Captain of the Port Baltimore to 

assist in enforcing the safety zone 

described in paragraph (a) of this 

section. 

(d) Enforcement periods. This section 

will be enforced from 10 a.m. to 6 p.m. 

on September 11, 2014, from 10 a.m. to 

6 p.m. on September 12, 2014, from 10 

a.m. to 6 p.m. on September 13, 2014, 

and from 10 a.m. to 6 p.m. on 

September 14, 2014. 

Dated: July 7, 2014. 

M. Dean, 

Commander, U.S. Coast Guard, Acting 

Captain of the Port Baltimore. 

[FR Doc. 2014–17103 Filed 7–18–14; 8:45 am] 

BILLING CODE 9110–04–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Parts 52 and 81 

[EPA–R09–OAR–2013–0735; FRL–9913–61– 

OAR] 

Approval of Implementation Plans and 

Designation of Areas for Air Quality 

Planning Purposes; Las Vegas Valley, 

Nevada; Redesignation to Attainment 

for PM10

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Proposed rule. 

SUMMARY: The Environmental Protection 

Agency (EPA) is proposing to approve a 

revision to the Nevada state 

implementation plan that provides for 

the maintenance of the national ambient 

air quality standard for particulate 

matter with an aerodynamic diameter 

less than or equal to a nominal ten 

micrometers (PM10) in Las Vegas Valley 

for the next ten years and to approve the 

related motor vehicle emissions 

budgets. Based in part on the proposed 

approval of the PM10 maintenance plan, 

EPA is also proposing to approve the 

State of Nevada’s request for 

redesignation of Las Vegas Valley to 

attainment for the PM10 standard. 

Consistent with the assumptions of the 

maintenance plan, EPA is proposing to 

approve revisions to certain local 

fugitive dust rules to ensure their 

continued applicability after 

redesignation of the area to attainment. 

Lastly, EPA is proposing to delete the 

area designation for Las Vegas Valley for 

the revoked national standard for total 

suspended particulate because the 

designation is no longer necessary. 

DATES: Comments must be received on 

or before August 20, 2014. 

ADDRESSES: Submit your comments, 

identified by Docket ID Number EPA– 

R09–OAR–2013–0735, by one of the 

following methods: 

1. http://www.regulations.gov: Follow 

the on-line instructions for submitting 

comments. 

2. E-Mail: oconnor.karina@epa.gov. 

3. Mail or Deliver: Karina OConnor 

(AIR–2), U.S. Environmental Protection 

Agency, Region IX, 75 Hawthorne 

Street, San Francisco, CA 94105–3901. 

Deliveries are only accepted during the 

Regional Office’s normal hours of 

operation. 

Instructions: All comments will be 

included in the public docket without 

change and may be made available 

online at http://www.regulations.gov, 

including any personal information 

provided, unless the comment includes 

Confidential Business Information (CBI) 

or other information whose disclosure is 

restricted by statute. Information that 

you consider CBI or otherwise protected 

should be clearly identified as such and 

should not be submitted through 

http://www.regulations.gov or email. 

http://www.regulations.gov is an 

anonymous access system, and EPA will 

not know your identity or contact 

information unless you provide it in the 

body of your comment. If you send 

email directly to EPA, your email 

address will be automatically captured 

and included as part of the public 

comment. If EPA cannot read your 

comment due to technical difficulties 

and cannot contact you for clarification, 

EPA may not be able to consider your 

comment. 

Docket: Documents in the docket for 

this action are generally available 

electronically at www.regulations.gov 

and in hard copy at EPA Region IX, 75 

Hawthorne Street, San Francisco, 

California. While all documents in the 

docket are listed at www.regulations 

.gov, some information may be publicly 

available only at the hard copy location 

(e.g., copyrighted material, large maps), 

and some may not be publicly available 

in either location (e.g., CBI). To inspect 

the hard copy materials, please schedule 

an appointment during normal business 

hours with the contact listed in the FOR

FURTHER INFORMATION CONTACT section. 

FOR FURTHER INFORMATION CONTACT: 

Karina O’Connor, Air Planning Office 

(AIR–2), U.S. Environmental Protection 

Agency, Region IX, (775) 434–8176, 

oconnor.karina@epa.gov. 

SUPPLEMENTARY INFORMATION: 

Throughout this document, whenever 

‘‘we,’’ ‘‘us,’’ or ‘‘our’’ is used, we mean 

the EPA. This SUPPLEMENTARY

INFORMATION section is arranged as 

follows: 

Table of Contents 

I. Summary of Today’s Proposed Action 

II. Background 

III. Procedural Requirements for Adoption 

and Submittal of SIP Revisions 

IV. Substantive Requirements for 

Redesignation 

V. Evaluation of the State’s Redesignation 

Request for the Las Vegas Valley PM10

Nonattainment Area 

A. Determination That the Area Has 

Attained the PM10 NAAQS. 

B. The Area Must Have a Fully-Approved 

SIP Meeting Requirements Applicable 

for Purposes of Redesignation Under 

Section 110 and Part D. 

1. Basic SIP Requirements Under CAA 

Section 110 

2. SIP Requirements Under Part D 

3. Conclusion With Respect to Sections 

107(d)(3)(E)(ii) and (v) 

C. The Area Must Show the Improvement 

in Air Quality Is Due to Permanent and 

Enforceable Emissions Reductions. 

D. The Area Must Have a Fully-Approved 

Maintenance Plan Under CAA Section 

175A. 

1. Attainment Inventory 

2. Maintenance Demonstration 

3. Monitoring Network 

4. Verification of Continued Attainment 

5. Contingency Provisions 

6. Subsequent Maintenance Plan Revisions 

7. Motor Vehicle Emissions Budgets 

VI. Evaluation of Revisions to Clark County 

Fugitive Dust Rules 

VII. Proposed Deletion of TSP Designation for 

Las Vegas Valley 

VIII. Proposed Action and Request for Public 

Comment 

IX. Statutory and Executive Order Reviews 

I. Summary of Today’s Proposed Action 

Under Clean Air Act (CAA or ‘‘Act’’) 

section 110(k)(3), EPA is proposing to 

approve a submittal from the Nevada 

Division of Environmental Protection 

(NDEP) dated September 7, 2012 of the 

Redesignation Request and 

Maintenance Plan for Particulate Matter 

(PM10), Clark County, Nevada (August 

2012) (‘‘Las Vegas Valley PM10

Maintenance Plan’’) as a revision to the 

Nevada state implementation plan (SIP). 

EPA finds that the Las Vegas Valley 

PM10 Maintenance Plan adequately 

demonstrates that the area will maintain 

the PM10 national ambient air quality 

standard (NAAQS or ‘‘standard’’) for 10 

years beyond redesignation and 

includes sufficient contingency 

provisions to promptly correct any 

violation of the PM10 standard which 

occurs after redesignation and thereby 

meets the requirements for maintenance 

plans under CAA section 175A. EPA is 

also proposing to approve the motor 

vehicle emissions budgets (MVEBs) in 

the Las Vegas Valley PM10 Maintenance 

Plan because we find they meet the 


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1The Las Vegas Valley encompasses roughly 

1,500 square miles within Clark County and 

includes the cities of Las Vegas, North Las Vegas, 

and Henderson. Roughly two million people reside 

in Clark County, mostly within Las Vegas Valley. 

NDEP is the state agency under state law that is 

responsible for SIP matters for the State of Nevada. 

Within Clark County, the Clark County Board of 

County Commissioners, acting through the Clark 

County Department of Air Quality (Clark County 

DAQ), is empowered under state law to develop air 

quality plans and to regulate stationary sources 

within the county with the exception of certain 

types of power plants, which lie exclusively within 

the jurisdiction of NDEP. 

2 In 2006, EPA retained the 24-hour PM10

standard but revoked the annual PM10 standard. See 

71 FR 61144 (October 17, 2006). More recently, as 

part of the Agency’s periodic review of the NAAQS, 

EPA reaffirmed the 24-hour PM10 NAAQS. See 78 

FR 3086 (January 15, 2013). See 40 CFR 50.6 

(‘‘National primary and secondary ambient air 

quality standards for PM10’’). 

applicable transportation conformity 

requirements under 40 CFR 93.118(e). 

Under CAA section 107(d)(3)(D), EPA 

is also proposing to approve NDEP’s 

request to redesignate the Las Vegas 

Valley PM10 nonattainment area from 

‘‘nonattainment’’ to ‘‘attainment’’ for the 

PM10 standard. We are doing so based 

on our conclusion that the Las Vegas 

Valley has attained the PM10 standard; 

that the relevant portions of the Nevada 

SIP are fully approved; that the 

improvement in air quality is due to 

permanent and enforceable emissions 

reductions; that the State of Nevada has 

met all of the requirements applicable to 

the Las Vegas Valley PM10

nonattainment area with respect to 

section 110 and part D of the CAA; and, 

based on our proposed approval as 

described above, that the Las Vegas 

Valley PM10 Maintenance Plan meets 

the requirements for maintenance plans 

under section 175A of the CAA; and 

that, therefore, the State of Nevada has 

met the criteria for redesignation under 

CAA section 107(d)(3)(E) for the Las 

Vegas Valley PM10 nonattainment area. 

Third, we are proposing to approve 

certain fugitive dust rules that Clark 

County has amended to ensure their 

continued applicability after the area is 

redesignated to attainment. NDEP 

submitted the amended rules on May 

27, 2014 as a revision to the Nevada SIP. 

Lastly, EPA is proposing to delete the 

area designation for Las Vegas Valley for 

the revoked NAAQS for total suspended 

particulate. 

II. Background 

On April 30, 1971 (36 FR 8186), 

pursuant to section 109 of the CAA, as 

amended in 1970, EPA promulgated the 

original NAAQS for the ‘‘criteria’’ 

pollutants, which included carbon 

monoxide, hydrocarbons, nitrogen 

dioxide, photochemical oxidant, sulfur 

dioxide, and particulate matter. The 

NAAQS are set at concentrations 

intended to protect public health and 

welfare. The original NAAQS for 

particulate matter was defined in terms 

of a reference method that called for 

measuring particulate matter up to a 

nominal size of 25 to 45 micrometers or 

microns. This fraction of total ambient 

particulate matter is referred to as ‘‘total 

suspended particulate’’ or TSP. Within 

nine months thereafter, each State was 

required under section 110 of the 1970 

amended Act to adopt and submit to 

EPA a plan, referred to as a State 

Implementation Plan (SIP), which 

provides for the implementation, 

maintenance, and enforcement of each 

of the NAAQS within each State. The 

State of Nevada submitted its SIP on 

January 28, 1972, and EPA approved it 

later that year. See 37 FR 10842 (May 

31, 1972). 

Generally, SIPs were to provide for 

attainment of the NAAQS within three 

years after EPA approval of the plan. 

However, many areas of the country did 

not attain the NAAQS within the 

statutory period. In response, Congress 

amended the Act in 1977 to establish a 

new approach, based on area 

designations, for attaining the NAAQS. 

Under section 107(d) of the 1977 

amended Act, States were to make 

recommendations for all areas within 

their borders as attainment, 

nonattainment, or unclassifiable for 

each of the NAAQS, including TSP, and 

EPA was to designate areas based on 

those recommendations, as modified if 

appropriate. For the State of Nevada, the 

State recommended, and EPA approved, 

the use of hydrographic areas as the 

geographic basis for designating air 

quality planning areas. See 67 FR 12474 

(March 19, 2002). For the TSP NAAQS, 

EPA designated a number of areas in 

Nevada as ‘‘nonattainment,’’ including 

Las Vegas Valley 1 (hydrographic area 

(HA) #212). See 43 FR 8962, at 9012 

(March 3, 1978). The area designations 

for air quality planning purposes within 

the State of Nevada are codified at 40 

CFR 81.329. 

As amended in 1977, the CAA 

required States to revise their SIPs by 

January 1979 for all designated 

nonattainment areas. The various local 

entities and the State of Nevada 

responded by developing and 

submitting attainment plans for the TSP 

nonattainment areas, including Las 

Vegas Valley, and in 1981, EPA 

approved these plans on condition that 

the State submit, within a prescribed 

period of time, revisions to correct 

certain deficiencies. See 46 FR 21758 

(April 14, 1981). In 1982, we found that 

the State had submitted the required 

revisions correcting the identified 

deficiencies, and we revoked the 

conditions placed on our approval of 

the TSP plans. See 47 FR 15790 (April 

13, 1982). 

In 1987, EPA revised the NAAQS for 

particulate matter, eliminating TSP as 

the indicator for the NAAQS and 

replacing it with the ‘‘PM10’’ indicator. 

See 52 FR 24634 (July 1, 1987). PM10

refers to particles with an aerodynamic 

diameter less than or equal to a nominal 

10 microns. At that time, EPA 

established two PM10 standards: A 24- 

hour standard of 150 micrograms per 

cubic meter (mg/m3) and an annual 

standard of 50 mg/m3.2 We indicated in 

the preamble to our regulations 

implementing the then-new PM10

NAAQS that we would consider 

deletion of TSP area designations once 

EPA had reviewed and approved 

revised SIPs that include control 

strategies for the PM10 NAAQS and once 

EPA had promulgated PM10 increments 

for the prevention of significant 

deterioration (PSD) program. See 52 FR 

24672, at 24682 (July 1, 1987). 

Under our regulations for 

implementing the revised particulate 

matter NAAQS (i.e., the PM10 NAAQS), 

EPA did not designate areas as 

nonattainment, attainment, or 

unclassifiable but categorized areas into 

three groups, referred to as Group I, 

Group II, or Group III. Group I areas 

were those that had a probability of not 

attaining the PM10 NAAQS (based on 

existing TSP data) of at least 90%. 

Group I areas were required to submit 

SIP revisions that contain full PM10

control strategies including a 

demonstration of attainment. See 52 FR 

24672, at 24681 (July 1, 1987). We 

identified the Las Vegas (HA #212) and 

Reno (HA #87, known as ‘‘Truckee 

Meadows’’) planning areas as Group I 

areas. See 52 FR 29383 (August 7, 1987) 

and 55 FR 45799 (October 31, 1990). 

The CAA was significantly amended 

in 1990. Under the 1990 amended Act, 

Congress replaced the PM10 regulatory 

approach established by EPA in 1987 

with the area designation concept and 

designated former ‘‘Group I’’ areas and 

certain other areas as nonattainment 

areas for PM10 by operation of law. See 

section 107(d)(4)(B) of the Act. As 

former ‘‘Group I’’ areas, the Las Vegas 

planning area was designated as 

nonattainment areas for PM10 by 

operation of law. See 56 FR 11101 

(March 15, 1991). 

Las Vegas Valley was initially 

classified as a ‘‘moderate’’ PM10

nonattainment area but was later reclassified as a ‘‘serious’’ PM10

nonattainment area. See 58 FR 3334 

(January 8, 1993). States with ‘‘serious’’ 


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3 In June 1992, the State of Nevada requested that 

we reclassify the eight existing TSP nonattainment 

areas in Nevada to ‘‘unclassifiable’’ status. See letter 

from L.H. Dodgion, Administrator, NDEP, to Daniel 

W. McGovern, Regional Administrator, EPA Region 

IX, dated June 15, 1992. We believe that deletion 

of the TSP nonattainment designations is 

administratively more efficient than redesignation 

of the area to unclassifiable. As noted above, we 

have already deleted six of the TSP nonattainment 

area designations and are proposing to delete the 

one for Las Vegas Valley herein. We will consider 

deletion of the one other remaining TSP area 

designation, i.e., the TSP designation for Reno (HA 

#87, Truckee Meadows), in a future rulemaking. 

4NDEP’s September 7, 2012 submittal of the Las 

Vegas Valley PM10 Maintenance Plan became 

complete by operation of law on March 7, 2013. 

PM10 nonattainment areas were required 

under the CAA, as amended in 1990, to 

submit revisions to their SIPs to, among 

other things, demonstrate attainment of 

the PM10 standard as expeditiously as 

practicable, but no later than 2001. See 

CAA section 188(c). However, EPA is 

authorized to extend the attainment date 

for such an area by up to 5 years if the 

State qualifies for an extension under 

the terms specified in the statute. See 

CAA section 188(e). To qualify, among 

other requirements, a State must 

demonstrate that the plan includes the 

most stringent measures (MSM) that are 

included in the SIP of any State or are 

achieved in practice in any State, and 

can feasibly be implemented in the area. 

In 2001, NDEP submitted the PM–10 

State Implementation Plan for Clark 

County (June 2001) (‘‘Las Vegas Valley 

PM10 Attainment Plan’’) to EPA as a 

revision to the Nevada SIP to meet the 

requirements for ‘‘serious’’ PM10

nonattainment areas. In 2002, NDEP 

submitted certain amendments to the 

Las Vegas Valley PM10 Attainment Plan 

and a set of local fugitive dust rules 

relied upon by the plan. In 2004, EPA 

approved the Las Vegas Valley PM10

Attainment Plan, as amended, and the 

set of fugitive dust rules. See 69 FR 

32273 (June 9, 2004). 

Specifically, as part of our 2004 final 

action, EPA approved the following SIP 

elements: 

• The baseline and projected 

emissions inventories as required under 

CAA section 172(c)(3); 

• The demonstration that attainment 

of the 24-hour standard by December 31, 

2001 is impracticable as required under 

CAA section 189(b)(1)(A); 

• The demonstration that attainment 

of the 24-hour standard will occur by 

the most expeditious alternative date 

practicable, in this case, December 31, 

2006, as required under CAA sections 

189(b)(1)(A) and 188(e); 

• The demonstration that the plan 

includes MSM as required under CAA 

section 188(e); 

• The demonstration that the plan 

provides for implementation of best 

available control measures (BACM) as 

required under CAA section 

189(b)(1)(B); 

• The demonstration that major 

sources of PM10 precursors such as 

nitrogen oxides and sulfur dioxide do 

not significantly contribute to violations 

of the PM10 standards as authorized 

under CAA section 189(e); 

• The demonstration that the plan 

provides for reasonable further progress 

and quantitative milestones as required 

under CAA sections 189(c) and 

172(c)(2); 

• The contingency measures as 

required under CAA section 172(c)(9); 

• Transportation conformity motor 

vehicle emissions budgets, including a 

budget of 141.41 tons per day beginning 

in year 2006; and 

• Clark County fugitive dust rules: 

Section 90 (‘‘Fugitive Dust from Open 

Areas and Vacant Lots’’), section 91 

(‘‘Fugitive Dust from Unpaved Roads, 

Unpaved Alleys and Unpaved Easement 

Roads’’), section 92 (‘‘Fugitive Dust from 

Unpaved Parking Lots, Material 

Handling & Storage Yards, & Vehicle & 

Equipment Storage Yards’’), section 93 

(‘‘Fugitive Dust from Paved Roads & 

Street Sweeping Equipment’’), and 

section 94 (‘‘Permitting & Dust Control 

for Construction Activities’’). 

As noted above, EPA approved the 

demonstration in the Las Vegas Valley 

PM10 Attainment Plan of December 31, 

2006 as the most expeditious practicable 

alternative attainment date, and in 2010, 

based on a review of the ambient 

monitoring data for years 2004–2006, 

EPA determined that the Las Vegas 

Valley PM10 nonattainment area had 

attained the 24-hour PM10 NAAQS by 

the approved alternative attainment 

date, i.e., December 31, 2006. See 75 FR 

45485 (August 3, 2010). 

On September 7, 2012, NDEP 

submitted the Las Vegas Valley PM10

Maintenance Plan and requested that 

EPA redesignate the Las Vegas Valley 

PM10 nonattainment area to attainment 

for the 24-hour PM10 NAAQS, and on 

May 27, 2014, NDEP submitted revised 

versions of Clark County’s fugitive dust 

rules that were amended by Clark 

County to ensure their continued 

applicability once the area is 

redesignated to attainment. In today’s 

proposed rule, we are proposing action 

on NDEP’s September 7, 2012 submittal 

of the Las Vegas Valley PM10

Maintenance Plan and request for 

redesignation to attainment, as well as 

the amended Clark County fugitive dust 

rules. 

The 1990 Act Amendments also 

provided for the continued transition 

from TSP to PM10. Specifically, section 

107(d)(4)(B) states in relevant part: 

‘‘Any designation for particulate matter 

(measured in terms of total suspended 

particulates) that the Administrator 

promulgated pursuant to this subsection 

(as in effect immediately before 

November 15, 1990) shall remain in 

effect for purposes of implementing the 

maximum allowable increases in 

concentrations of particulate matter 

(measured in terms of total suspended 

particulates) pursuant to section 163(b) 

of this title, until the Administrator 

determines that such designation is no 

longer necessary for that purpose.’’ 

Section 166(f) of the 1990 amended 

Act authorizes EPA to replace the TSP 

increments with PM10 increments, and 

in 1993, EPA promulgated the PM10

increments and revised the PSD 

regulations accordingly. See 58 FR 

31622 (June 3, 1993). In our June 1993 

final rule, we indicated that the 

replacement of the TSP increments with 

PM10 increments negates the need for 

the TSP attainment or unclassifiable 

area designations to be retained. We also 

indicated that we would delete such 

TSP designations in 40 CFR part 81 

upon the occurrence of, among other 

circumstances, EPA’s approval of a 

State’s or local agency’s revised PSD 

program containing the PM10

increments. See 58 FR 31622, at 31635 

(June 3, 1993). 

In November 2002, we deleted the 

TSP attainment or unclassifiable area 

designations throughout the State of 

Nevada, except for those in Clark 

County. See 67 FR 68769 (November 13, 

2002). In April 2013, we deleted the 

TSP attainment or unclassifiable area 

designations within Clark County and 

deleted the TSP nonattainment area 

designations for all of the Nevada TSP 

nonattainment areas, except for the Las 

Vegas planning area (i.e., HA #212, Las 

Vegas Valley) and the Reno planning 

area (i.e., HA #87, Truckee 

Meadows).3 See 78 FR 22425 (April 16, 

2013). In today’s proposed rule, we are 

proposing to delete the TSP 

nonattainment area designation for Las 

Vegas Valley. 

III. Procedural Requirements for 

Adoption and Submittal of SIP 

Revisions 

Sections 110(a)(1) and 110(l) of the 

Act require States to provide reasonable 

notice and public hearing prior to 

adoption of SIP revisions. In this action, 

we are proposing action on NDEP’s 

September 7, 2012 submittal of the Las 

Vegas Valley PM10 Maintenance Plan 

(August 2012) as a revision to the 

Nevada SIP.4 We are also proposing 

action on NDEP’s May 27, 2014 


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5For PM10, a complete set of data includes a 

minimum of 75 percent of the scheduled PM10

samples per quarter. See 40 CFR part 50, Appendix 

K, section 2.3(a). 

submittal of Clark County’s amended 

fugitive dust rules as a revision to the 

Nevada SIP. These two submittals 

contain documentation of the public 

review process followed by Clark 

County and NDEP in adopting the SIP 

revisions prior to submittal to EPA. As 

discussed below, the documentation 

provides sufficient evidence that 

reasonable notice of public hearings was 

provided to the public and that public 

hearings were conducted prior to 

adoption. 

NDEP’s submittal of the Las Vegas 

Valley PM10 Maintenance Plan includes 

a letter dated August 27, 2012 from 

Lewis Wallenmeyer, Director, Clark 

County Department of Air Quality 

(Clark County DAQ), to Colleen Cripps, 

Administrator, NDEP, submitting the 

Las Vegas Valley PM10 Maintenance 

Plan and redesignation request to NDEP. 

NDEP’s letter dated September 7, 2012 

transmitting the plan to EPA and 

requesting that EPA approve the plan 

and redesignation request constitutes 

NDEP’s adoption of the plan as a 

revision to the Nevada SIP. 

Appendix B (‘‘Documentation of the 

Public Review Process’’) of the Las 

Vegas Valley PM10 Maintenance Plan 

includes a copy of the notice to the 

public published in a newspaper of 

general circulation on January 15, 2012 

announcing a 30-day comment period 

on the proposed Las Vegas Valley PM10

Maintenance Plan and a public hearing 

after the close of the comment period; 

a copy of comments received and Clark 

County DAQ’s responses; various web 

notices issued by Clark County DAQ in 

connection with review of the proposed 

plan; and documentation of the public 

hearing on the proposed plan and 

subsequent adoption of the plan by the 

Clark County Board of County 

Commissioners on August 21, 2012. 

These materials adequately document 

the public review process followed by 

Clark County in adopting the plan prior 

to transmittal to NDEP and provide 

sufficient evidence that reasonable 

notice of a public hearing was provided 

to the public and that a public hearing 

was conducted prior to adoption. 

NDEP’s May 27, 2014 submittal of 

Clark County’s amended fugitive dust 

rules includes documentation of the 

public process used by Clark County to 

adopt the changes, including 

publication of notice of a 30-day public 

review and comment period (February 

22, 2014–March 25, 2014) and related 

public hearing in a newspaper of 

general circulation. As documented in 

the submittal, Clark County Board of 

County Commissioners adopted the 

amendments on April 15, 2014, effective 

April 29, 2014. 

Based on the documentation included 

in NDEP’s submittals, discussed above, 

we find that the submittals of the Las 

Vegas Valley PM10 Maintenance Plan 

and the amended fugitive dust rules as 

SIP revisions satisfy the procedural 

requirements of sections 110(a) and 

110(l) of the Act for revising SIPs. 

IV. Substantive Requirements for 

Redesignation 

The CAA establishes the requirements 

for redesignation of a nonattainment 

area to attainment. Specifically, section 

107(d)(3)(E) allows for redesignation 

provided that the following criteria are 

met: (1) EPA determines that the area 

has attained the applicable NAAQS; (2) 

EPA has fully approved the applicable 

implementation plan for the area under 

section 110(k); (3) EPA determines that 

the improvement in air quality is due to 

permanent and enforceable reductions 

in emissions resulting from 

implementation of the applicable SIP, 

applicable federal air pollution control 

regulations, and other permanent and 

enforceable reductions; (4) EPA has 

fully approved a maintenance plan for 

the area as meeting the requirements of 

CAA section 175A; and (5) the State 

containing such area has met all 

requirements applicable to the area 

under section 110 and part D of the 

CAA. 

EPA provided guidance on 

redesignations in a document titled, 

‘‘State Implementation Plans; General 

Preamble for the Implementation of 

Title I of the Clean Air Act Amendments 

of 1990,’’ published in the Federal 

Register on April 16, 1992 (57 FR 

13498), and supplemented on April 28, 

1992 (57 FR 18070). Other relevant EPA 

guidance documents include: 

‘‘Procedures for Processing Requests to 

Redesignate Areas to Attainment,’’ 

Memorandum from John Calcagni, 

Director, Air Quality Management 

Division, EPA Office of Air Quality 

Planning and Standards, September 4, 

1992 (referred to herein as the ‘‘Calcagni 

memo’’); ‘‘Part D New Source Review 

(part D NSR) Requirements for Areas 

Requesting Redesignation to 

Attainment,’’ Memorandum from Mary 

D. Nichols, Assistant Administrator for 

Air and Radiation, October 14, 1994; 

and ‘‘State Implementation Plans for 

Serious PM10 Nonattainment Areas, and 

Attainment Date Waivers for PM10

Nonattainment Areas Generally; 

Addendum to the General Preamble for 

the Implementation of title I of the 

Clean Air Act Amendments of 1990,’’ 59 

FR 41998 (August 16, 1994). 

For the reasons set forth below in 

section V of this document, we propose 

to approve NDEP’s request for 

redesignation of the Las Vegas Valley 

PM10 nonattainment area to attainment 

for the 24-hour PM10 NAAQS based on 

our conclusion that all of the criteria 

under CAA section 107(d)(3)(E) have 

been satisfied. 

V. Evaluation of the State’s 

Redesignation Request for the Las 

Vegas Valley PM10 Nonattainment Area 

A. Determination That the Area Has 

Attained the PM10 NAAQS 

CAA section 107(d)(3)(E)(i) states that, 

for an area to be redesignated to 

attainment, EPA must determine that 

the area has attained the relevant 

NAAQS. In this case, the relevant 

NAAQS is the PM10 NAAQS. As noted 

above, in 2010, EPA determined that the 

Las Vegas Valley nonattainment area 

attained the PM10 standard by the area’s 

applicable attainment date of December 

31, 2006 based on data for years 2004– 

2006. Today’s action updates this 

determination based on the most recent 

available PM10 monitoring data. 

Generally, EPA determines whether 

an area’s air quality is meeting the 24- 

hour PM10 NAAQS based upon 

complete,5 quality-assured, and certified 

data gathered at established state and 

local air monitoring stations (SLAMS) in 

the nonattainment area and entered into 

the EPA Air Quality System (AQS) 

database. EPA will consider air quality 

data from air monitoring stations other 

than SLAMS in the nonattainment area 

provided those stations meet the federal 

monitoring requirements for SLAMS, 

including the quality assurance and 

quality control criteria in 40 CFR part 

58, appendix A. See 40 CFR 58.20; 71 

FR 61236, 61242; (October 17, 2006). 

Data from air monitors operated by 

state, local, or tribal agencies in 

compliance with EPA monitoring 

requirements must be submitted to 

AQS. These monitoring agencies certify 

annually that these data are accurate to 

the best of their knowledge. 

Accordingly, EPA relies primarily on 

data in AQS when determining the 

attainment status of an area. See 40 CFR 

50.6; 40 CFR part 50, appendices J and 

K; 40 CFR part 53; and, 40 CFR part 58, 

appendices A, C, D, and E. All valid 

data are reviewed to determine the 

area’s air quality status in accordance 

with 40 CFR part 50, appendix K. 

Attainment of the 24-hour PM10

standard is determined by calculating 

the expected number of exceedances of 

the standard in a year. The 24-hour 

PM10 standard is attained when the 


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6See, e.g., letter from Meredith Kurpius, Manager, 

Air Quality Analysis Office, EPA Region IX, to Phil 

Wiker, Engineering Manager, Clark County DAQ, 

dated December 11, 2013, approving the relevant 

portions of Clark County DAQ’s 2013 Annual 

Network Plan. 

7See EPA Region IX, Technical System Audit 

Report, Clark County Department of Air Quality 

Ambient Air Monitoring Program, July 26–July 27, 

2012, Final report, July 2013, page 8. Enclosed with 

letter from Deborah Jordan, Director, Air Division, 

U.S. EPA Region IX, to Lewis Wallenmeyer, Clark 

County DAQ (August 1, 2013). 

8See, e.g., letter from Lewis Wallenmeyer, Clark 

County DAQ, to Fletcher Clover, Air Quality 

Analysis Office, EPA Region IX, certifying 2013 

ambient air quality data and quality assurance data 

(April 22, 2014). 9EPA has approved Clark County DAQ’s 

discontinuation of PM10 monitoring at these sites. 

See letter from Matthew Lakin, U.S. EPA Region IX, 

to Mike Sword, Clark County DAQ (June 5, 2013) 

(Lone Mountain and Orr sites), and letter from 

Meredith Kurpius, U.S. EPA Region IX, to Mike 

Sword, Clark County DAQ (October 30, 2013) (Craig 

Road site). 10The new site is the Jerome Mack site, AQS ID: 

32–003–0540. In addition, in 2013, the Las Vegas 

Paiute tribe began monitoring for PM10 at an eighth 

site within the Las Vegas Valley PM10

nonattainment area. This eighth site has not been 

approved by EPA for NAAQS compliant 

monitoring. 

11Figure 2–1 of the Las Vegas Valley PM10

Maintenance Plan illustrates the locations of Clark 

County DAQ PM10 monitoring sites (other than 

Jerome Mack). 

12 In this context, ‘‘middle scale’’ refers to 

conditions characteristic of areas from 100 meters 

to half a kilometer, and ‘‘neighborhood scale’’ refers 

to conditions throughout some reasonably 

homogeneous urban sub-region with dimensions of 

a few kilometers. See 40 CFR part 58, appendix D, 

section 4.6. 

13 40 CFR 50.1(j), (k), (l); 50.14; 51.930. 

14See letter from Jared Blumenfeld, EPA Region 

IX, to Lewis Wallenmeyer, Clark County DAQ, 

dated June 25, 2014. 

expected number of exceedances 

averaged over a three-year period is less 

than or equal to one at each monitoring 

site within the nonattainment area. 

Three consecutive years of air quality 

data are required to show attainment of 

the 24-hour PM10 standard. See 40 CFR 

part 50 and appendix K. More than 

three years may be considered if all 

additional representative years of data 

meeting the 75 percent criterion are 

utilized. Data not meeting these criteria 

may also suffice to show attainment; 

however, such exceptions must be 

approved by the appropriate Regional 

Administrator in accordance with EPA 

guidance. See 40 CFR part 50, appendix 

K, section 2.3. 

Clark County DAQ is responsible for 

monitoring ambient air quality within 

Clark County. Clark County submits 

annual monitoring network plans to 

EPA. These network plans describe the 

monitoring network operated by Clark 

County DAQ within Clark County. 

These plans discuss the status of the air 

monitoring network, as required under 

40 CFR 58.10. 

EPA regularly reviews these annual 

plans for compliance with the 

applicable reporting requirements in 40 

CFR part 58. With respect to PM10, EPA 

has found that the area’s network plans 

meet the applicable reporting 

requirements under 40 CFR part 58.6

EPA also concluded from its 2012 

Technical System Audit that Clark 

County DAQ’s monitoring network 

currently meets or exceeds the 

requirements for the minimum number 

of SLAMS for PM10 in the Las Vegas 

Valley nonattainment area.7 Clark 

County DAQ annually certifies that the 

data it submits to AQS are complete and 

quality-assured.8

During the 2004–2006 period, Clark 

County DAQ operated 13 PM10 SLAMS 

monitoring sites within Las Vegas 

Valley. See 75 FR 45485, at 45488 

(August 3, 2010). Between 2006 and 

2009, four of the sites were closed or 

stopped monitoring PM10. In 2010, Clark 

County DAQ discontinued PM10

monitoring at three more sites: Lone 

Mountain (northwest Las Vegas), Orr 

School (central-southeast Las Vegas), 

and Craig Road (North Las Vegas).9

Notwithstanding the decrease in the 

number of PM10 monitoring sites, Clark 

County DAQ continues to meet EPA 

requirements for the minimum number 

of PM10 monitoring sites in Clark 

County. 

In 2012, Clark County DAQ 

established a new PM10 monitoring 

site,10 and thus, at the present time, 

Clark County DAQ operates seven PM10

SLAMS monitoring sites within Las 

Vegas Valley: Green Valley (Henderson), 

J.D. Smith School (North Las Vegas), Joe 

Neal (northwest Las Vegas), Paul Meyer 

Park (southwest Las Vegas), Palo Verde 

School (west Las Vegas), Sunrise Acres 

School (central Las Vegas), and Jerome 

Mack (east Las Vegas).11 All seven sites 

monitor PM10 concentrations on a 

continuous, year-round basis using beta 

attenuation methods. See Clark County 

DAQ’s Annual Monitoring Network Plan 

Report (June 2013). Each of these 

methods has been granted the Federal 

Equivalent Method (FEM) designation 

by EPA. The PM10 monitoring sites have 

been established to monitor for 

population exposure in the middle or 

neighborhood scale.12

Consistent with the requirements 

contained in 40 CFR part 50, EPA has 

reviewed the quality-assured and 

certified PM10 ambient air monitoring 

data as recorded in AQS for the 

applicable monitoring period collected 

at the monitoring sites in the Las Vegas 

Valley nonattainment area and 

determined that the data are of 

sufficient completeness for the purposes 

of making comparisons with the PM10

standards. 

EPA’s review of monitoring data for 

the PM10 standard for Las Vegas Valley 

includes exceedances of the standard 

recorded during the 2011–2013 time 

period. However, EPA is excluding the 

exceedances of the standard in 2011 

from the attainment determination 

presented herein because they were the 

result of an exceptional event. On April 

16, 2014 Clark County DAQ submitted 

a demonstration for a high wind PM10

exceptional event covering the two 

exceedances recorded on July 3, 2011 at 

the J.D. Smith and Sunrise Acres 

monitoring sites. EPA reviewed the 

documentation that Clark County DAQ 

provided to demonstrate that the 

exceedances on these days meet the 

criteria for an exceptional event under 

EPA’s Exceptional Events Rule (EER).13

EPA concurred with Clark County 

DAQ’s request for exceptional event 

determination that, based on the weight 

of evidence, the two exceedances were 

caused by a high wind exceptional 

event.14 Accordingly, EPA has 

determined that the monitored 

exceedances associated with this 

exceptional event should be excluded 

from use in determinations of 

exceedances and violations, including 

the evaluation of whether Las Vegas 

Valley has attained the standard for the 

purposes of redesignation under CAA 

section 107(d)(3)(E)(i). 

Table 1 below shows the maximum 

24-hour PM10 concentrations monitored 

at the seven PM10 sites over the most 

recent three-year period (2011–2013) 

and lists the calculated expected 

exceedances per year at each of the sites 

over that same period. As shown in 

table 1 below, exceedances were 

monitored at four of the sites in 2012, 

and at all of the sites in 2013. All of the 

exceedances in 2012 were recorded on 

May 10, 2012, and all of the 

exceedances in 2013 were recorded on 

two days, April 15 and October 28, 

2013. Clark County DAQ has flagged 

these exceedances as exceptional 

events. As noted above in connection 

with the 2011 exceedances, if EPA 

concurs on exceedances as exceptional 

events, they are excluded from the 

determination of whether the area is 

attaining the NAAQS, but EPA has not 

taken action to concur on any of the 

exceedances in 2012 or 2013, and thus, 

the 2012 and 2013 exceedances are not 

being excluded from today’s evaluation. 


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15The applicable SIP for NDEP and Clark County 

may be found at http://yosemite.epa.gov/r9/

r9sips.nsf/allsips?readform&state=Nevada. We note 

that SIPs must be fully approved only with respect 

to applicable requirements for purposes of 

redesignation in accordance with section 

107(d)(3)(E)(ii). Thus, for example, CAA section 

110(a)(2)(D) requires that SIPs contain certain 

measures to prevent sources in a state from 

significantly contributing to air quality problems in 

another state. However, the section 110(a)(2)(D) 

requirements for a state are not linked with a 

particular nonattainment area’s designation and 

classification in that state. EPA believes that the 

requirements linked with a particular 

nonattainment area’s designation and classification 

are the relevant measures to evaluate in reviewing 

a redesignation request. The transport SIP submittal 

requirements, where applicable, continue to apply 

to a state regardless of the designation of any one 

particular area in the state. 

Thus, we do not believe that these requirements 

should be construed to be applicable requirements 

for purposes of redesignation. In addition, EPA 

believes that the other section 110 elements not 

connected with nonattainment plan submissions 

and not linked with an area’s attainment status are 

not applicable requirements for purposes of 

redesignation. The State will still be subject to these 

requirements after Las Vegas Valley is redesignated. 

The section 110 and part D requirements, which are 

linked with a particular area’s designation and 

classification, are the relevant measures to evaluate 

in reviewing a redesignation request. This policy is 

consistent with EPA’s existing policy on 

applicability of conformity (i.e., for redesignations) 

and oxygenated fuels requirement. See Reading, 

Pennsylvania, proposed and final rulemakings 61 

FR 53174–53176 (October 10, 1996), 62 FR 24826 

(May 7, 1997); Cleveland-Akron-Lorain, Ohio, final 

rulemaking 61 FR 20458 (May 7, 1996); and Tampa, 

Florida, final rulemaking 60 FR 62748 (December 7, 

1995). See also the discussion of this issue in the 

Cincinnati redesignation at 65 FR 37890 (June 19, 

2000), in the Pittsburgh redesignation at 66 FR 

53099 (October 19, 2001), and in the Los Angeles 

redesignation at 72 FR 6986 (February 14, 2007) and 

72 FR 26718 (May 11, 2007). EPA believes that 

section 110 elements not linked to the area’s 

nonattainment status are not applicable for 

purposes of redesignation. 

16 In 2012, EPA took final limited approval and 

limited disapproval action on updated new source 

review (NSR) rules adopted by Clark County and 

Continued 

TABLE 1—SUMMARY OF LAS VEGAS VALLEY PM10 MONITORING DATA, 2011–2013 

Monitoring site 

(AQS Monitor ID) 

Highest 24-hour PM10 concentration (μg/m3) 2nd Highest 24-hour PM10 concentration (μg/m3) Expected 

exceedances 

per year 

2011 2012 2013 2011 2012 2013 

2011–2013 

Green Valley (32–003– 

0298) ........................ 143 145 b 196 82 125 88 0.3 

J.D. Smith (32–003– 

2002) ........................ 71 b 203 b 237 66 82 b 169 1.0 

Jerome Mack (32–003– 

0540) ........................ NA b 228 b 243 NA 138 121 a 0.7 

Joe Neal (32–003– 

0075) ........................ 130 b 182 b 226 100 88 131 0.7 

Palo Verde (32–003– 

0073) ........................ 89 138 b 212 43 94 119 0.3 

Paul Meyer (32–003– 

0043) ........................ 103 147 b 164 62 139 74 0.3 

Sunrise Acres (32– 

003–0561) ................ 85 b 211 b 267 66 81 136 0.7 

NA = Not applicable. The Jerome Mack site opened in 2012. 

aThe listed design value is not valid because it does not meet completeness requirements. 

bValues represent exceedances of the 150 μg/m3 NAAQS. Violations occur when the ‘‘expected exceedances per year’’ averaged over a 

three-year period exceed 1.0. 

Source: Letter and attachments from Lewis Wallenmeyer, Clark County DAQ, to Fletcher Clover, Air Quality Analysis Office, EPA Region IX, 

certifying 2013 ambient air quality data and quality assurance data (April 22, 2014). 

Based on a review of air quality data 

during the most recent complete threeyear period (2011–2013) (summarized 

above in table 1) and without excluding 

the 2012 or 2013 exceedances, we find 

that the expected number of 

exceedances per year for Las Vegas 

Valley is 1.0 days per year (based on the 

J.D. Smith monitoring site). The 24-hour 

PM10 standard is attained when the 

expected number of exceedances 

averaged over a three-year period is less 

than or equal to one at each monitoring 

site within the nonattainment area. 

Therefore, we find that, based on 

complete, quality-assured, and certified 

data for three most recent years (2011– 

2013) that the Las Vegas Valley PM10

nonattainment area has attained the 24- 

hour PM10 standard. SLAMS data for 

2014 are not yet available from these 

monitoring sites but will be reviewed 

prior to final action to ensure that they 

are consistent with continued 

attainment. 

B. The Area Must Have a Fully 

Approved SIP Meeting Requirements 

Applicable for Purposes of 

Redesignation Under Section 110 and 

Part D 

Section 107(d)(3)(E)(ii) and (v) require 

EPA to determine that the area has a 

fully-approved applicable SIP under 

section 110(k) that meets all applicable 

requirements under section 110 and part 

D for the purposes of redesignation. 

1. Basic SIP Requirements Under CAA 

Section 110 

Section 110(a)(2) sets forth the general 

elements that a SIP must contain in 

order to be fully approved. Although 

section 110(a)(2) was amended in 1990, 

a number of the requirements did not 

change in substance, and therefore, EPA 

believes that the pre-amendment EPAapproved SIP met these requirements in 

Clark County with respect to PM10. As 

to those requirements that were 

amended, (see 57 FR 27936 and 27939, 

June 23, 1992), many are duplicative of 

other requirements of the Act. 

On numerous occasions over the past 

38 years, NDEP has submitted, and we 

have approved, provisions addressing 

the basic CAA section 110 provisions. 

The Clark County portion of the 

approved Nevada SIP contains 

enforceable emission limitations; 

requires monitoring, compiling and 

analyzing of ambient air quality data; 

requires preconstruction review of new 

or modified stationary sources; provides 

for adequate funding, staff, and 

associated resources necessary to 

implement its requirements; and 

provides the necessary assurances that 

the State maintains responsibility for 

ensuring that the CAA requirements are 

satisfied in the event that Clark County 

is unable to meet its CAA obligations.15

There are no outstanding or 

disapproved applicable SIP submittals 

with respect to the Clark County portion 

of the SIP that prevent redesignation of 

the Las Vegas Valley PM10

nonattainment area for the 24-hour PM10

standard.16 Therefore, we find that 


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submitted as a revision to the Nevada SIP (77 FR 

64039, October 18, 2012) and issued a partial 

approval and partial disapproval of Nevada’s 

‘‘infrastructure’’ SIP for the 1997 8-hour ozone 

NAAQS and the 1997 and 2006 PM2.5 NAAQS (77 

FR 64737, October 23, 2012). While these two final 

rules are not full approvals, they do not represent 

an obstacle to redesignation of the Las Vegas Valley 

PM10 nonattainment area because the 

‘‘infrastructure’’ SIP elements that EPA disapproved 

are not related to the nonattainment SIP 

requirements for the Las Vegas Valley PM10

nonattainment area and thus are not relevant for the 

purposes of redesignation and because, 

notwithstanding the limited approval and limited 

disapproval of the amended NSR rules, the Clark 

County DAQ NSR rules continue to meet the 

fundamental SIP requirements for NSR in ‘‘serious’’ 

PM10 nonattainment areas. 

NDEP and Clark County have met all 

SIP requirements for Clark County 

applicable for purposes of redesignation 

under section 110 of the CAA (General 

SIP Requirements). 

2. SIP Requirements Under Part D 

Part D Requirements Other Than NSR or 

Conformity 

Subparts 1 and 4 of part D, title I of 

the CAA contain air quality planning 

requirements for PM10 nonattainment 

areas. Subpart 1 contains general 

requirements for all nonattainment areas 

of any pollutant, including PM10, 

governed by a NAAQS. The subpart 1 

requirements include, in relevant part, 

provisions for emissions inventories, 

reasonable further progress (RFP), a 

program for preconstruction review and 

permitting of new or modified major 

stationary sources (‘‘New Source 

Review,’’ or NSR), contingency 

measures, and conformity. 

Subpart 4 contains specific SIP 

requirements for PM10 nonattainment 

areas. The requirements set forth in 

CAA sections 189(a), (c), and (e) apply 

specifically to ‘‘moderate’’ PM10

nonattainment areas and include, in 

relevant part: (1) Provisions for 

implementation of reasonably available 

control measures (RACM); (2) 

quantitative milestones demonstrating 

RFP toward attainment by the 

applicable attainment date; and (3) 

provisions to ensure that the control 

requirements applicable to major 

stationary sources of PM10 also apply to 

major stationary sources of PM10

precursors except where EPA has 

determined that such sources do not 

contribute significantly to PM10 levels 

that exceed the NAAQS in the area. 

Under CAA section 189(b), ‘‘serious’’ 

PM10 nonattainment areas, such as Las 

Vegas Valley, must meet the ‘‘moderate’’ 

area requirements discussed above and, 

in addition, must develop and submit 

an attainment demonstration as well as 

provisions to assure the implementation 

of best available control measures 

(BACM) for the control of PM10. 

As noted previously, in 2004, EPA 

approved the PM–10 State 

Implementation Plan for Clark County 

(June 2001) (‘‘Las Vegas Valley PM10

Attainment Plan’’) as a revision to the 

Nevada SIP. See 69 FR 32273 (June 9, 

2004). The Las Vegas Valley PM10

Attainment Plan was developed to meet 

the SIP requirements for ‘‘serious’’ PM10

nonattainment areas under subparts 1 

and 4 of part D, except those related to 

NSR or conformity. More specifically, as 

part of our 2004 final action, EPA 

approved the Las Vegas Valley PM10

Attainment Plan as meeting the 

following requirements: Baseline and 

projected emissions inventories as 

required under CAA section 172(c)(3); 

the demonstration that the plan 

provides for RFP and quantitative 

milestones as required under CAA 

sections 172(c)(2) and 189(c); the 

contingency measures as required under 

CAA section 172(c)(9); the 

demonstration that major sources of 

PM10 precursors such as nitrogen oxides 

and sulfur dioxide do not significantly 

contribute to violations of the PM10

standards as provided in CAA section 

189(e); the attainment demonstration 

under CAA sections 189(b)(1)(A); and 

the demonstration that the plan 

provides for implementation of BACM 

as required under CAA section 

189(b)(1)(B). Because the demonstration 

of BACM subsumes the demonstration 

of RACM, a separate analysis to 

determine if the measures represent a 

RACM level of control was not 

necessary. EPA’s approval of the BACM 

demonstration in the Las Vegas Valley 

PM10 Attainment Plan, therefore, also 

represented a finding that the plan 

provides for the implementation of 

RACM as required under CAA section 

189(a)(1)(C). See 69 FR 32273 (June 9, 

2004). 

Thus, for the reasons given above, and 

excluding NSR and conformity, which 

we address separately below, we find 

that Clark County has a fully-approved 

PM10 SIP with respect to the part D 

requirements for RACM, BACM, and 

other serious PM10 area SIP 

requirements. 

Permits for New and Modified Major 

Stationary Sources 

To meet the requirements of CAA 

sections 172(c)(5) and 189(a)(1)(A), 

states must submit SIP revisions that 

meet the requirements under 40 CFR 

51.165 (‘‘Permit requirements’’). Under 

40 CFR 51.165, states are required to 

submit SIP revisions that establish 

certain requirements for new or 

modified stationary sources in 

nonattainment areas, including 

provisions to ensure that major new 

sources or major modifications of 

existing sources of nonattainment 

pollutants incorporate the highest level 

of control, referred to as the Lowest 

Achievable Emission Rate (LAER), and 

that increases in emissions from such 

stationary sources are offset so as to 

provide for reasonable further progress 

towards attainment in the 

nonattainment area. See CAA section 

173(a)(1)(A) and 40 CFR 

51.165(a)(9)(ii)(A). 

The process for reviewing permit 

applications and issuing permits for 

new or modified stationary sources of 

air pollution is referred to as ‘‘New 

Source Review’’ (NSR). With respect to 

nonattainment pollutants in 

nonattainment areas, this process is 

referred to as ‘‘nonattainment NSR.’’ 

With respect to pollutants for which an 

area is designated as attainment or 

unclassifiable, states are required to 

submit SIP revisions that ensure that 

major new stationary sources and major 

modifications of existing stationary 

sources meet the Federal requirements 

for Prevention of Significant 

Deterioration (PSD), including 

application of ‘‘best available control 

technology,’’ for each applicable 

pollutant emitted in significant 

amounts, among other requirements. 

Within the Las Vegas PM10

nonattainment area, two agencies are 

responsible for meeting the 

requirements for nonattainment NSR 

and PSD: NDEP and Clark County DAQ. 

Under Nevada law, exclusive NDEP 

jurisdiction extends to specific electric 

steam-generating emission units (i.e., 

power plants) throughout the State of 

Nevada, and thus, state regulations 

govern air pollution permits issued to 

those types of units within Clark 

County. Clark County DAQ is 

responsible for all other stationary 

source emissions units within Clark 

County, and Clark County regulations 

govern air pollutant permits issued to 

them. 

With respect to those sources that are 

under State jurisdiction, we have 

approved a State rule (Nevada 

Administrative Code (NAC) section 

445B.22083) that prohibits new power 

plants or major modifications to existing 

power plants under State jurisdiction 

within the Las Vegas Valley 

nonattainment area. See 69 FR 31056, 

31059 (June 2, 2004) and 69 FR 54006, 

at 54017 (September 7, 2004). In 2008, 

we approved an amended version of 

NAC section 445B.22083 that clarifies 

the application of NSR requirements to 

any relocation of power generating 

units. See 73 FR 20536 (April 16, 2008). 


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17The deficiencies that have any bearing on PM10

are limited to a few definitions: ‘‘allowable 

emissions,’’ ‘‘baseline actual emissions,’’ ‘‘net 

emissions increase,’’ and ‘‘major modification.’’ See 

77 FR 64039, at 64047 (October 18, 2012). 

The submittal and approval of the 

State’s prohibition on new major power 

plants or major modifications to existing 

power plants in Las Vegas Valley 

adequately substitutes for submittal and 

approval of a SIP revision meeting 

nonattainment NSR requirements in Las 

Vegas Valley with respect to sources 

under NDEP jurisdiction. 

With respect to sources under Clark 

County DAQ jurisdiction, we approved 

Clark County’s NSR rules as meeting the 

requirements of section 172(c)(5) and, 

for PM10, section 189(a)(1)(A). See 69 FR 

54006 (September 7, 2004); also, see our 

proposed rule at 69 FR 31056, at 31059 

(June 2, 2004) for details on how Clark 

County’s NSR rules complied with CAA 

requirements for PM10 nonattainment 

areas. In recent years, Clark County 

DAQ has adopted comprehensive 

changes to its NSR program and, in 

2012, EPA issued a limited approval 

and limited disapproval for the revised 

program. See 77 FR 64039 (October 18, 

2012). With respect to nonattainment 

NSR, EPA found a number of 

deficiencies; however, the Clark County 

NSR rules continue to meet the basic 

requirements for a serious PM10

nonattainment NSR area, including a 

definition of ‘‘major stationary source’’ 

as a stationary source which emits, or 

has the potential to emit, seventy (70) 

tons per year or more of PM10, emissions 

limitations that constitute LAER, and 

emissions reductions to offset emissions 

increases that would otherwise occur.17

See Clark County section 12.3.2 

(‘‘Definitions,’’ subsection (y) ‘‘Major 

Stationary Source’’); 12.3.5.2 (‘‘Permit 

Requirements to Achieve LAER’’); and 

12.3.6 (‘‘Emissions Offset’’). 

Moreover, Clark County’s SIPapproved NSR rules have served as a 

federally-enforceable constraint on the 

growth of stationary source emissions, 

and thus have supported the region’s 

efforts to lower ambient PM10

concentrations in Las Vegas Valley. 

Therefore, given the prohibition on new 

sources or major modifications of 

existing sources under NDEP 

jurisdiction and given that the 

fundamental nonattainment NSR 

requirements are approved into the SIP 

for sources under Clark County DAQ 

jurisdiction, we conclude that the State 

has met the applicable NSR 

requirements for the Las Vegas PM10

nonattainment area for the purposes of 

redesignation of the area to attainment 

for the PM10 standard. 

General and Transportation Conformity 

Requirements 

Under section 176(c) of the Clean Air 

Act Amendments of 1990, States are 

required to establish criteria and 

procedures to ensure that Federally 

supported or funded projects conform to 

the air quality planning goals in the 

applicable SIP. Section 176(c) further 

provided that State conformity 

provisions must be consistent with 

Federal conformity regulations that the 

CAA required EPA to promulgate. EPA’s 

conformity regulations are codified at 40 

CFR part 93, subparts A (referred to 

herein as ‘‘transportation conformity’’) 

and B (referred to herein as ‘‘general 

conformity’’). Transportation conformity 

applies to transportation plans, 

programs, and projects developed, 

funded, and approved under title 23 

U.S.C. or the Federal Transit Act, and 

general conformity applies to all other 

Federally-supported or funded projects. 

SIP revisions intended to address the 

conformity requirements are referred to 

herein as ‘‘conformity SIPs.’’ 

In November 2008, EPA approved 

Clark County’s transportation 

conformity criteria and procedures as 

meeting the related SIP requirements 

under part 51, subpart T (‘‘Conformity 

to State or Federal Implementation 

Plans of Transportation Plans, Programs, 

and Projects Developed, Funded or 

Approved Under Title 23 U.S.C. or the 

Federal Transit Laws’’). See 73 FR 

66182 (November 7, 2008). 

In August 2005, Congress passed the 

Safe, Accountable, Flexible, Efficient 

Transportation Equity Act: A Legacy for 

Users (SAFETEA–LU), which 

eliminated the requirement for States to 

adopt and submit conformity SIPs 

addressing general conformity 

requirements. See 75 FR 17254 (April 5, 

2010) for conforming changes to EPA’s 

general conformity regulations. Based 

on our approval of Clark County’s 

transportation conformity SIP and 

SAFETEA–LU’s elimination of the 

general conformity SIP requirement, we 

find that Clark County and the State 

have met the requirements for 

conformity SIPs in the Las Vegas Valley 

PM10 nonattainment area under CAA 

section 176(c). In any event, EPA 

believes it is reasonable to interpret the 

conformity requirements as not 

applicable for purposes of evaluating a 

redesignation request under section 

107(d)(3)(E). See Wall v. EPA, 265 F.3d 

426, 439 (6th Cir. 2001) upholding this 

interpretation. 

3. Conclusion With Respect to Sections 

107(d)(3)(E)(ii) and (v) 

Thus, EPA finds, based on our review 

of EPA’s previous rulemakings on the 

relevant portions of the Nevada SIP and 

for the reasons provided above, that the 

Las Vegas Valley has a fully approved 

applicable SIP under section 110(k) that 

meets all applicable requirements under 

section 110 and part D for the purposes 

of redesignation, and thereby meets the 

criteria for redesignation under CAA 

sections 107(d)(3)(E)(ii) and (v). 

C. The Area Must Show the 

Improvement in Air Quality Is Due to 

Permanent and Enforceable Emissions 

Reductions 

Section 107(d)(3)(E)(iii) precludes 

redesignation of a nonattainment area to 

attainment unless EPA determines that 

the improvement in air quality is due to 

permanent and enforceable emissions 

reductions resulting from 

implementation of the applicable SIP 

and applicable Federal air pollution 

control regulations and other permanent 

and enforceable regulations. Under this 

criterion, the state must be able to 

reasonably attribute the improvement in 

air quality to emissions reductions 

which are permanent and enforceable. 

Attainment resulting from temporary 

reductions in emissions rates (e.g., 

reduced production or shutdown due to 

temporary adverse economic 

conditions) or unusually favorable 

meteorology would not qualify as an air 

quality improvement due to permanent 

and enforceable emission reductions. 

See the Calcagni memo, page 4. 

The Las Vegas Valley PM10

Maintenance Plan credits a number of 

local and Federal control measures for 

having reduced PM10 emissions and 

concentrations within Las Vegas Valley 

sufficiently to attain the NAAQS, and 

relies on their continued 

implementation to provide for 

maintenance of the NAAQS now that 

the NAAQS has been attained. The local 

control measures cited in the 

maintenance plan include certain Clark 

County Air Quality Regulations (AQR), 

such as the NSR rule (AQR section 12), 

the acid rain permit rule (AQR section 

21), and the fugitive dust rules (AQR 

sections 90 through 94); best available 

retrofit technology to meet the 

requirements of EPA’s regional haze 

rule; the transportation conformity 

process; and the Clark County Natural 

Events Action Plan. Federal control 

measures cited in the maintenance plan 

include the National Emissions 

Standards for Hazardous Air Pollutants 

(NESHAPs) and Standards of 


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18The 90 series rules include Clark County AQR 

section 90 (‘‘Fugitive Dust from Open Areas and 

Vacant Lots’’), section 91 (‘‘Fugitive Dust from 

Unpaved Roads, Unpaved Alleys and Unpaved 

Easement Roads’’), section 92 (‘‘Fugitive Dust from 

Unpaved Parking Lots, Material Handling & Storage 

Yards, & Vehicle & Equipment Storage Yards’’), 

section 93 (‘‘Fugitive Dust from Paved Roads & 

Street Sweeping Equipment’’), and section 94 

(‘‘Permitting & Dust Control for Construction 

Activities’’). 

19 In this context, the design value at each 

monitoring site refers to the first-, second-, third-, 

or fourth-highest measured concentration 

(depending on the frequency of monitoring) over a 

three-year period. The highest design valley among 

the monitoring sites determines the design value for 

the nonattainment area. A design value for a given 

year reflects the data for that year and the previous 

two years. For example, a design value for 2002 

reflects 2000–2002 data. 

20See population figures in table 4–1 of the Las 

Vegas Valley PM10 Maintenance Plan. 

21See section 4.3 of the Las Vegas Valley PM10

Maintenance Plan for wind and rainfall data in Las 

Vegas Valley. 

22PM10 precursor emissions may also be required 

depending upon the contribution of secondarilyformed particulate matter to ambient PM10

concentrations. As discussed in our proposed 

approval of the Las Vegas Valley PM10 Attainment 

Plan, 68 FR 2958 (January 22, 2003), Clark County 

determined, based on analyses of inventories (see 

chapter 4, section 4.2.1 of the Attainment Plan) and 

Chemical Mass Balance modeling, that secondary 

particulate contributes less than significant 

amounts to ambient PM10 concentrations. 

Therefore, PM10 precursors, including oxides of 

nitrogen, sulfur dioxide and volatile organic 

compounds, are not included in the Las Vegas 

Valley PM10 Maintenance Plan, and we find their 

absence acceptable. 

Performance for New Stationary Sources 

(NSPS). 

While we agree that all of the 

measures cited above contributed to 

attainment and will contribute to 

maintenance of the PM10 NAAQS in Las 

Vegas Valley, the backbone of the 

control strategy that provided for 

attainment of the PM10 NAAQS was 

Clark County’s section 90 series 

regulations governing fugitive dust 

sources. Clark County’s section 12 NSR 

rule and local ordinances (Clark County, 

and the cities of Las Vegas, North Las 

Vegas, and Henderson) regulating new 

fireplaces also contributed to attainment 

of the standard and will contribute to 

maintenance of the standard. 

In our approval of the BACM 

demonstration in the Las Vegas Valley 

PM10 Attainment Plan, we described the 

BACM analysis in terms of a series of 

steps intended to identify all of the 

sources or source categories that 

significantly contribute to exceedances 

of the NAAQS and to provide for 

implementation of BACM for all of 

those sources or source categories. Clark 

County’s approved BACM 

demonstration identified certain fugitive 

dust sources, including disturbed vacant 

land/unpaved parking lots, construction 

(including highway construction), 

paved roads, unpaved roads, and race 

tracks as the source categories that 

significantly contribute to exceedances 

of the PM10 NAAQS in Las Vegas 

Valley. See 68 FR 2954, at 2959 (January 

22, 2003). In the approved Las Vegas 

Valley PM10 Attainment Plan, Clark 

County further demonstrated how Clark 

County AQR sections 90 through 94 

implemented BACM for the relevant 

source categories.18 EPA approved these 

regulations as part of the SIP at the same 

time that EPA approved the Las Vegas 

Valley PM10 Attainment Plan, 69 FR 

32273 (June 9, 2004), and since then, the 

Clark County fugitive dust regulations 

have been federally enforceable. Clark 

County’s section 12 NSR rule has been 

approved as part of the SIP, most 

recently at 77 FR 64039 (October 18, 

2012), as have the local fireplace 

ordinances cited above, 68 FR 52838 

(September 8, 2003). 

We also note that Clark County’s 90 

series regulations were implemented in 

the early 2000s, and a rough indication 

of their impact on ambient PM10

concentrations can be seen in figure 2– 

2 in the Las Vegas Valley PM10

Maintenance Plan that shows a steep 

decline in design values 19 for Las Vegas 

Valley from the late 1990s beginning in 

2002 to a level below the NAAQS 

beginning in 2005. This improvement 

occurred despite a 30 percent increase 

in population in Las Vegas Valley 

during the same period.20 Thus, the 

improvement in air quality since 2000 

may reasonably be attributed to 

implementation of Clark County’s 90 

series (i.e., fugitive dust) rules. 

Moreover, while we recognize that 

annual rainfall during the 2003–2005 

period in Las Vegas Valley was higher 

than normal, we note that the 

downward trend in concentrations 

began prior to that time and that 

maintenance of the NAAQS has 

continued since the mid-2000s despite 

lower-than-normal rainfall from 2006– 

2009.21

Thus, we find that the improvement 

in air quality in the Las Vegas Valley 

PM10 nonattainment area is the result of 

permanent and enforceable emissions 

reductions from a combination of 

permanent and enforceable measures, 

including, but not limited to fugitive 

dust rules, the NSR rule, and fireplace 

ordinances, and is not the result of 

adverse economic conditions or unusual 

meteorological conditions. As such, we 

find that the criterion for redesignation 

set forth at CAA section 107(d)(3)(E)(iii) 

is satisfied. 

D. The Area Must Have a FullyApproved Maintenance Plan Under 

CAA Section 175A 

Section 175A of the CAA sets forth 

the elements of a maintenance plan for 

areas seeking redesignation from 

nonattainment to attainment. Under 

CAA section 175A, a maintenance plan 

must demonstrate continued attainment 

of the applicable NAAQS for at least ten 

years after EPA approves a 

redesignation to attainment. Eight years 

after redesignation, the State must 

submit a revised maintenance plan that 

demonstrates continued attainment for 

the subsequent ten-year period 

following the initial ten-year 

maintenance period. To address the 

possibility of future NAAQS violations, 

the maintenance plan must contain such 

contingency provisions as EPA deems 

necessary to promptly correct any 

violation of the NAAQS that occurs after 

redesignation of the area. 

To meet these requirements, 

maintenance plans should include the 

following core elements: Attainment 

inventory, maintenance demonstration, 

continuation of an adequate monitoring 

network, verification of continued 

attainment, and contingency plan. See 

Calcagni memo, pages 8 through 13. 

Based on our review and evaluation of 

the plan, as detailed below, we are 

proposing to approve the Las Vegas 

Valley PM10 Maintenance Plan because 

we have found that it meets the 

requirements of CAA section 175A. 

1. Attainment Inventory 

A maintenance plan for the 24-hour 

PM10 standard must include an 

inventory of emissions of PM10 in the 

area to identify a level of emissions 

sufficient to attain the 24-hour PM10

NAAQS.22 This inventory must be 

consistent with EPA’s most recent 

guidance on emissions inventories for 

nonattainment areas available at the 

time and should represent emissions 

during the time period associated with 

the monitoring data showing 

attainment. The inventory must also be 

comprehensive, including emissions 

from stationary point sources, area 

sources, nonroad mobile sources, and 

on-road mobile sources, and must be 

based on actual emissions during the 

appropriate season or episode, if 

applicable. In the following paragraphs, 

we summarize our findings with respect 

to the emissions inventories prepared 

for the Las Vegas Valley PM10

Maintenance Plan. 

First, emissions inventories for 

attainment or maintenance plans are 

generally developed for the entire 

nonattainment area. For the Las Vegas 

Valley PM10 Maintenance Plan, Clark 

County DAQ developed emissions 


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23The Las Vegas Valley PM10 Maintenance Plan 

explains that most of the land in Nevada is under 

federal jurisdiction, and most of the federal land is 

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 the boundary for this area in 

2003, and minor adjustments thereafter. The area 

currently comprises approximately 327,000 acres 

and is known as the BLM disposal area. 

24 ‘‘Point sources’’ refer to those stationary source 

facilities that are required to report their emissions 

to Clark County DAQ or NDEP. 

25 ‘‘Nonpoint sources’’ refer to those stationary 

and area sources that fall below point source 

reporting levels and that are too numerous or small 

to identify individually. 

inventories for a subset of the 

nonattainment area referred as to the 

BLM disposal area.23 See figure 1–1 in 

the Las Vegas Valley PM10 Maintenance 

Plan for a map showing the BLM 

disposal area in relation to the Las 

Vegas Valley PM10 nonattainment area. 

EPA accepted the BLM disposal area as 

the geographic basis for the emissions 

inventories in the Las Vegas Valley 

PM10 Attainment Plan (see 68 FR 2954, 

at 2958 (January 22, 2003), and we do 

so again for the Las Vegas Valley PM10

Maintenance Plan. The BLM disposal 

area remains an appropriate geographic 

basis for air quality planning purposes 

because more than 99 percent of the 

population within the nonattainment 

area lives within BLM disposal area, 

more than 98 percent of the vehicle 

miles traveled within the nonattainment 

area occurs within the BLM disposal 

area, and nearly all of the anthropogenic 

sources within the nonattainment area 

are located within the BLM disposal 

area. 

Furthermore, most of the area within 

the nonattainment area but outside the 

BLM disposal area lies under the 

jurisdiction of the federal government, 

and all lands controlled by the federal 

government outside the BLM disposal 

area are to remain in their native or 

managed state. The disposal area 

boundary can only be changed by an act 

of Congress. Continued reliance on the 

BLM disposal area for air quality 

planning purposes was confirmed in 

2007 by a PM10 monitoring study 

conducted by Clark County DAQ under 

which samplers were deployed outside 

the BLM disposal area. No violations 

were recorded. We note that, while the 

inventory corresponds to the BLM 

disposal area, the regulations adopted 

by Clark County DAQ to address PM10

sources apply to the entire PM10

nonattainment area. 

Second, as to the year selected for 

attainment inventory purposes, Clark 

County DAQ selected year 2008 as the 

year for the attainment inventory in the 

Las Vegas Valley PM10 Maintenance 

Plan. Emissions during year 2008 are 

reflected in three three-year periods that 

could be used to evaluate whether the 

area is attaining the standard: 2006– 

2008, 2007–2009, and 2008–2010. In the 

latter two periods, the expected number 

of exceedances averaged over the 

relevant three-year period was less than 

1.0, which reflects attainment 

conditions. The period 2006–2008 has 

an expected number of exceedances of 

1.1, which represents a violation of the 

standard; however, the value of 1.1 

reflects two exceedances for which 

Clark County DAQ has flagged as 

exceptional events. Under these 

circumstances, we do not believe that 

the violation calculated for the 2006– 

2008 period should preclude the 

selection of 2008 for the inventory and 

find its selection by Clark County DAQ 

to be acceptable. 

Third, the emissions inventories 

developed by Clark County DAQ for the 

Las Vegas Valley PM10 Maintenance 

Plan reflect ‘‘design day’’ conditions. 

The specific day selected for emissions 

inventory purposes was April 15, 2008. 

Clark County DAQ selected that day 

based on a review of data from all of the 

PM10 monitoring sites that operated 

from 2008 through 2010 that showed 

April 15, 2008 to be the day during 

which the highest PM10 concentration 

not unduly affected by high-wind events 

was measured. We find the use of a 

design day inventory, and selection of 

April 15, 2008 as the specific day for the 

inventory, to be acceptable. 

Fourth, as to comprehensiveness, we 

find that the emissions inventories in 

the maintenance plan to be 

comprehensive in that they include 

estimates of PM10 from all of the 

relevant source categories, which the 

plan divides among point sources,24

nonpoint sources,25 on-road mobile 

sources, nonroad mobile sources, and 

emission reduction credits. See table 6– 

2 of the Las Vegas Valley PM10

Maintenance Plan for a summary of the 

attainment inventory (2008), as well as 

future year emissions projections for 

years 2015 and 2023. Appendix A to the 

PM10 Maintenance Plan contains sourcecategory-specific descriptions of 

emission calculation procedures and 

sources of input data. 

Table 2 below summarizes the 

attainment inventory (for 2008) in the 

Las Vegas Valley PM10 Maintenance 

Plan, and also summarizes the plan’s 

projected emissions inventories for an 

interim year (2015) and the maintenance 

plan’s horizon year (2023). Based on the 

estimates in table 2, the nonpoint 

category of emissions accounted for 

nearly 99% of the PM10, with wind 

erosion from vacant lands making up 

62%, wind erosion from construction 

making up 26%, and paved road dust 

and construction emissions each making 

up 4% of the total PM10 inventory for 

2008. 

TABLE 2—TOTAL DAILY LAS VEGAS VALLEY PM10 EMISSIONS, 2008, 2015, AND 2023 

Category Subcategory 

PM10 (tons per day) a

2008 2015 2023 

Point ............................................................................ ..................................................................................... 2.19 2.60 2.88 

Nonpoint ...................................................................... Wind Erosion (Vacant Lands) .................................... 439.05 288.16 122.77 

Wind Erosion (construction) ....................................... 183.97 217.70 249.21 

Construction ............................................................... 30.93 37.69 41.22 

Paved Road ................................................................ 30.85 38.04 48.78 

Unpaved Road ........................................................... 5.84 6.51 7.49 

Other ........................................................................... 6.59 7.24 7.89 

On-Road Motor Vehicles ............................................ ..................................................................................... 3.08 2.52 2.75 

Nonroad Mobile Sources ............................................ ..................................................................................... 3.74 2.95 1.94 

Emission Reductions Credits ...................................... ..................................................................................... 0.31 0.31 0.31 

Totals ................................................................... ..................................................................................... 706.55 603.72 485.24 

aEmissions correspond to the BLM disposal Area portion of the Las Vegas Valley nonattainment area and reflect design day conditions. 

Source: Derived from estimates in table 6–2 of the Las Vegas Valley PM10 Maintenance Plan. 


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26The EPA’s most recent action on Nevada’s I/M 

program updated the corresponding State statutes 

and rules. 73 FR 38124 (July 3, 2008). 

Lastly, we reviewed the methods, 

factors, and assumptions used by Clark 

County DAQ to develop the emissions 

inventories in the Las Vegas Valley 

PM10 Maintenance Plan to ensure that 

the inventories are consistent with 

EPA’s most recent guidance for such 

inventories. As noted above, Clark 

County DAQ’s inventory is divided into 

five broad categories (point sources, 

nonpoint sources, on-road mobile 

sources, nonroad mobile sources, and 

emission reduction credits). Multiple 

subcategories of emissions are 

calculated within each of these broad 

categories. 

For point sources, Clark County DAQ 

based the inventory estimates on sourcereported actual 2008 emissions data. For 

nonpoint or area wide sources, Clark 

County calculated emissions based on 

county-wide reported data for fuel 

usage, product sales, population, 

employment data, land area, and other 

parameters covering a wide range of 

activities. The largest emission sources 

for the PM10 inventory, wind erosion 

from construction and wind erosion 

from vacant lands, are included in 

nonpoint emissions. These two source 

categories contribute over 80% of the 

total PM10 emissions in 2008. Emission 

factors for windblown fugitives were 

developed based on a series of windtunnel studies conducted by University 

of Nevada, Las Vegas (UNLV). These 

emission factors were combined with 

estimates of vacant land and developed 

land from the Clark County Department 

of Comprehensive Planning (DCP)’s 

Geographic Integrated Land Use 

Information System (GILIS). 

The nonroad mobile source category 

includes aircraft, boats, and off-road 

vehicles and equipment used for 

construction, farming, commercial, 

industrial, and recreational activities. 

With respect to such sources, Clark 

County DAQ used EPA’s nonroad 

emissions model NONROAD2008a, the 

current version of the model at the time 

the plan was created. The model 

includes both emissions factors and 

default county level population and 

activity data. The model estimates both 

emissions factors and emissions. This 

includes more than 80 basic and 260 

specific types of non-road equipment, 

and further stratifies equipment by 

horsepower rating and fuel type. The 

model has default estimates, variables 

and factors used in the calculations. No 

local data sets were available for Clark 

County, therefore only model defaults 

were used. 

The on-road mobile source category 

consists of trucks, automobiles, buses, 

and motorcycles. The on-road emissions 

inventory estimates in the Las Vegas 

Valley PM10 Maintenance Plan were 

prepared by Clark County DAQ using 

EPA’s Motor Vehicle Emissions 

Simulator (MOVES2010a) model and 

AP–42. The vehicle miles traveled were 

developed from vehicle activity data 

from the Regional Transportation 

Commission of Southern Nevada (RTC) 

using the transportation demand model, 

TransCAD. 

The on-road emissions estimates for 

the Las Vegas Valley PM10 Maintenance 

Plan assumed the implementation of the 

federal heavy-duty diesel rule, limits to 

Reid Vapor Pressure (RVP) of 9 pounds 

per square inch (PSI) with a 1.0 psi 

waiver for ethanol-blended fuels, the 

phase-in of federal tier 2 motor vehicle 

emission standards, and the 

continuation of the SIP-approved 

enhanced vehicle inspection and 

maintenance (I/M) program in the urban 

areas of Clark County.26

Based on our review of the emissions 

inventories (and related documentation) 

from the Las Vegas Valley PM10

Maintenance Plan, we find that the 

inventory for 2008 is comprehensive, 

that the methods and assumptions used 

by Clark County to develop the emission 

inventory are reasonable, and that, 

therefore, the 2008 inventory reasonably 

estimates actual PM10 emissions in an 

attaining year. Moreover, we find that 

the emissions inventory in the PM10

Maintenance Plan reflects the latest 

planning assumptions and emissions 

models available at the time the plan 

was developed, and provides a 

comprehensive and reasonably accurate 

basis upon which to forecast PM10

emissions for years 2015 and 2023. 

2. Maintenance Demonstration 

Section 175A(a) of the CAA requires 

a demonstration of maintenance of the 

NAAQS for 10 years after redesignation. 

A state may generally demonstrate 

maintenance of the NAAQS by either 

showing that future emissions of a 

pollutant or its precursors will not 

exceed the level of the attainment 

inventory, or by modeling to show that 

the future anticipated mix of sources 

and emission rates will not cause a 

violation of the NAAQS. See Calcagni 

memo, pages 9 through 11. 

The Las Vegas Valley PM10

Maintenance Plan includes emissions 

inventory projections for 2015 and 2023 

and corresponding estimates of futureyear design values to demonstrate 

maintenance through 2023. In doing so, 

Clark County DAQ relies on ‘‘rollback,’’ 

the scaling of measured concentrations 

proportional to emissions, with 

conservative assumptions for the 

rollback concentration target and for the 

background concentration. In this case, 

Clark County DAQ predicted future year 

design values by adjusting a 2008 design 

value by the proportional change in 

overall PM10 emissions from the 

attainment inventory (2008) relative to 

the inventories for the future years 

(2015 and 2023), taking into account a 

background level (on the design value 

day) of approximately 40 mg/m3. We 

find Clark County DAQ’s use of a 

‘‘rollback’’ type of analysis appropriate 

in this case given that ambient PM10

concentrations in Las Vegas Valley are 

driven primarily by ground-level direct 

PM10 emissions (in particular fugitive 

dust) with generally consistent 

dispersion characteristics. 

The foundation for the maintenance 

demonstration is the emissions 

projections for year 2015 and 2023 

because, using the rollback method, the 

predicted future year design values will 

remain below the attainment-year 

design value (and thus below the 

NAAQS) if the emissions projections for 

the future years are less than the 

attainment-year inventory. In this case, 

Clark County DAQ identified 98 mg/m3

as the design value for 2008 (40 mg/m3

of which represents the background as 

noted above). The design value of 98 mg/ 

m3 excludes two exceedances measured 

in Las Vegas Valley in 2008 that were 

flagged and documented by Clark 

County DAQ as exceptional events. EPA 

has not taken action to concur, or not to 

concur, on the flagged exceedances, and 

if the two exceedances were taken into 

account (in determining the design 

value rather than being excluded), the 

design value for 2008 would be 123 mg/ 

m3, rather than 98 mg/m3. Regardless of 

whether the 2008 design value is to be 

123 mg/m3 or 98 mg/m3, the general 

principle still applies because both 

design values are well below the 24- 

hour PM10 NAAQS of 150 mg/m3. 

Namely, if the future-year emissions 

projections remain below the emissions 

estimated for the attainment year, then 

future-year concentrations should 

remain below the design value for the 

attainment year and thus well below the 

NAAQS. 

Given the importance of the futureyear emissions projections, EPA 


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27See page 2–1 of appendix A (‘‘Technical 

Support Document’’) to the Las Vegas Valley PM10

Maintenance Plan. 

28See page 4–13 of appendix A (‘‘Technical 

Support Document’’) to the Las Vegas Valley PM10

Maintenance Plan. 

29See Las Vegas Valley PM10 Maintenance Plan, 

section 6.4.4. 

reviewed the methods and assumptions 

used by Clark County DAQ to adjust the 

attainment-year (2008) emissions 

inventory to develop emissions 

projections for 2015 and 2013, with 

particular attention paid to those source 

categories that contribute most to the 

overall inventory. The documentation 

for Clark County DAQ’s emissions 

projections are found in appendix A 

(‘‘Technical Support Document’’) to the 

Las Vegas Valley PM10 Maintenance 

Plan. 

One of the principle assumptions on 

which the maintenance plan is based is 

the continued implementation of Clark 

County’s fugitive dust rules, particularly 

the 90 series rules (i.e., sections 90 

through 94). As approved into the SIP, 

these rules, other than section 94, apply 

within the ‘‘PM10 nonattainment area.’’ 

Redesignation to attainment would 

presumably have undercut continued 

implementation of the rules. However, 

Clark County has recently amended the 

rules to apply within a PM10

nonattainment area or an area subject to 

a PM10 maintenance plan, to ensure 

continued applicability after the area is 

redesignated attainment, and thus to be 

consistent with the assumptions of the 

maintenance demonstration in the Las 

Vegas Valley PM10 Maintenance Plan. 

Because EPA cannot redesignate a 

nonattainment area to attainment 

without approval of a maintenance plan, 

see CAA section 107(d)(3)(E)(4), Clark 

County’s extension of applicability of 

the fugitive dust rules to areas subject to 

a maintenance plan ensures continued 

implementations of the rules after 

redesignation. In section VI of this 

document, we are proposing to approve 

the amended fugitive dust rules as a part 

of this action. 

As described in appendix A to the 

maintenance plan, Clark County DAQ 

relied primarily on growth factors 

generated by EPA’s Economic Growth 

Analysis System, Version 5 (EGAS); 

however, population forecasts were also 

used to estimate future-year emissions 

or activity throughput where applicable. 

With respect to population forecasts, 

Clark County DAQ relied on the most 

recent forecasts developed by the Center 

for Business and Economic Research 

(CBER) at the University of Nevada, Las 

Vegas (UNLV) using 2010 U.S. Census 

data. CBER forecasts a population 

increase from 2008 to 2015 of 8.6% and 

a population increase from 2008 to 2023 

of 25%.27 Examples of source categories 

for which population forecasts were 

used to develop the emissions 

projections include construction, wind 

erosion, and unpaved road sectors. We 

find this approach to be acceptable. 

While EGAS growth factors were used 

for many source categories, other than 

those driven by population, Clark 

County DAQ declined to use EGAS 

factors for certain sources or source 

categories if more accurate local data 

were available. These source and source 

categories and related data sources 

include Nellis Air Force Base; fuel 

consumption projections from the U.S. 

Energy Information Agency; Union 

Pacific railroad operations; and vehicle 

miles traveled (VMT) projections from 

the Regional Transportation 

Commission of Southern Nevada (RTC) 

for use in estimating entrainment of 

PM10 from vehicle travel over paved 

roads.28 Clark County DAQ also 

included banked emissions reduction 

credits (ERCs) for 2015 and 2023 in the 

event that the ERCs are used for the 

purposes of issuing permits for new or 

modified stationary sources in the air 

quality planning area.29 We find these 

data sources to be appropriate for use in 

developing emissions projections for the 

maintenance plan. 

Representing approximately 62% of 

the overall inventory, wind erosion over 

vacant lands represents the single 

largest source category in terms of its 

contribution to the overall PM10

inventory for year 2008 for the BLM 

disposal area. Clark County DAQ 

estimated that emissions from this 

category would decline from 

approximately 440 tons per day in 2008 

to 290 tons per day by 2015 and then 

to 123 tons per day by 2023. Given this 

significant predicted decrease in 

emissions relative to existing 

conditions, EPA reviewed in detail the 

assumptions and basis for these 

forecasts. 

As described in section 5.2 of 

appendix A to the Las Vegas Valley 

PM10 Maintenance Plan, the emissions 

projections for wind erosion from 

vacant lands were made using emissions 

factors that were developed based on a 

series of wind-tunnel studies conducted 

by UNLV, combined with soil inventory 

data based on satellite imagery and 

estimates of vacant land and developed 

land from the Clark County Department 

of Comprehensive Planning (DCP’s) 

Geographic Integrated Land Use 

Information System (GILIS), adjusted 

over time based on a vacant land 

consumption rate of approximately 

3,400 acres per year and projected 

population growth rates. The rate for 

vacant land consumption from 2011 to 

2023 is projected to be approximately 

23% less than the 30-year average 

vacant land consumption rate 

(approximately 4,400 acres per year). 

The decrease in emissions projected for 

the wind erosion over vacant lands 

reflects the reduction in total disturbed 

unstable lands within the BLM disposal 

area from approximately 10,100 acres in 

2008 to 8,200 acres in 2015 and then to 

6,100 acres in 2023. We believe Clark 

County DAQ’s approach to projecting 

emissions from this source category to 

be reasonable and find that projected 

decrease in emissions from this source 

category is logical given the extent to 

which the lands within the BLM 

disposal area are already developed or 

remain as native desert. 

Based on our review described above, 

we find that the methods, growth 

factors, and assumptions used by Clark 

County DAQ to project emissions in 

2015 and 2023 based on the attainment 

inventory for 2008 are reasonable. Given 

that the projections (summarized in 

Table 2 above) show future emissions in 

2015 (603.72 tons per day) and 2023 

(485.24 tons per day) to be well below 

those in 2008 (706.55 tons per day), we 

find that the projections provide an 

adequate basis to demonstrate 

maintenance of the PM10 NAAQS 

within the Las Vegas Valley area 

through 2023. Also, as described further 

in section V.D.7 of this document, Clark 

County DAQ has chosen to include 

‘‘safety margins’’ in the motor vehicle 

emissions budgets for 2015 (90.63 tons 

per day) and 2023 (78.29 tons per day), 

but we find that the overall emissions 

projections, including the safety 

margins for the budgets, for 2015 

(694.35 tons per day) and 2023 (563.53 

tons per day) remain below those in 

2008 (706.55 tons per day), and thus, 

the safety margins are consistent with 

maintenance of the NAAQS through 

2023. 

Lastly, we note that, under CAA 

section 175A(a), a maintenance plan 

must provide for maintenance of the 

NAAQS in the area ‘‘for at least 10 years 

after the redesignation.’’ Although final 

EPA action on this proposed 

redesignation will not occur until year 

2014, we find that the Las Vegas Valley 

PM10 Maintenance Plan satisfies the 

requirement to provide for maintenance 

of the NAAQS for at least 10 years after 

redesignation, which in this case, means 

through 2024, because (1) significant 

emissions controls (e.g. Clark County’s 

fugitive dust regulations) remain in 

place and will continue to provide 

reductions that keep the area in 


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30EPA’s requirements for annual review of 

monitoring networks are found at 40 CFR 58.10. 

attainment; (2) the 2023 projected 

emission inventory is well below the 

2008 attainment year level and is 

expected to decline or remain stable 

during the 2023 to 2024 period due to 

continued developed of lands within 

the BLM disposal area and 

corresponding reduction in wind 

erosion over vacant disturbed land; and 

(3) air quality concentrations are well 

below the 24-hour PM10 NAAQS, and, 

when coupled with the emission 

inventory projections through 2023, 

clearly show it would be very unlikely 

for a PM10 violation to occur in 2024. 

For the above reasons, EPA believes 

that the area will continue to maintain 

the 24-hour PM10 NAAQS at least 

through 2024 and that the Las Vegas 

Valley PM10 Maintenance Plan provides 

for maintenance for a period of ten years 

following redesignation. Thus, if EPA 

finalizes its proposed approval of the 

Las Vegas Valley PM10 Maintenance 

Plan in 2014, it is based on a showing, 

in accordance with section 175A, that 

the Las Vegas Valley PM10 Maintenance 

Plan provides for maintenance for at 

least ten years after redesignation. 

3. Monitoring Network 

Continued ambient monitoring of an 

area is generally required over the 

maintenance period. As discussed in 

section V.A. of this document, PM10 is 

currently monitored by Clark County 

DAQ within the Las Vegas Valley PM10

nonattainment area. In the Las Vegas 

Valley PM10 Maintenance Plan (see 

section 6–8 of the plan), Clark County 

commits to continue operation of an air 

quality monitoring network that meets 

or exceeds the minimum monitoring 

requirements and will be relying on 

ambient PM10 monitoring to verify 

continued attainment of the 24-hour 

PM10 NAAQS. The Las Vegas Valley 

PM10 Maintenance Plan also notes that 

a review of the entire monitoring 

network will be undertaken annually as 

required by federal regulations.30 We 

find Clark County’s commitment for 

continued ambient PM10 monitoring as 

set forth in the Las Vegas Valley PM10

Maintenance Plan to be acceptable. 

4. Verification of Continued Attainment 

Clark County has the legal authority 

to implement and enforce the 

requirements in the Las Vegas Valley 

PM10 Maintenance Plan. This includes 

the authority to adopt, implement and 

enforce any emission control 

contingency measures determined to be 

necessary to correct 24-hour PM10

NAAQS violations. To verify continued 

attainment, Clark County commits in 

the PM10 Maintenance Plan to the 

continued operation of a PM10

monitoring network that meets EPA 

ambient air quality surveillance 

requirements. 

Second, the transportation conformity 

process, which would require a 

comparison of on-road motor vehicle 

emissions that would occur under new 

or amended regional transportation 

plans and programs with the MVEBs in 

the Las Vegas Valley PM10 Maintenance 

Plan, represents another means by 

which to verify continued attainment of 

the 24-hour PM10 NAAQS in the Las 

Vegas Valley. Lastly, while not cited in 

the plan, Clark County must inventory 

emissions sources and report to EPA on 

a periodic basis under 40 CFR part 51, 

subpart A (‘‘Air Emissions Reporting 

Requirements’’). These emissions 

inventory updates will provide a third 

way to evaluate emissions trends in the 

area and thereby verify continued 

attainment of the NAAQS. These 

methods are sufficient for the purpose of 

verifying continued attainment. 

5. Contingency Provisions 

CAA section 175A(d) requires that 

maintenance plans include contingency 

provisions, as EPA deems necessary, to 

promptly correct any violations of the 

NAAQS that occur after redesignation of 

the area. Such provisions must include 

a requirement that the State will 

implement all measures with respect to 

the control of the air pollutant 

concerned that were contained in the 

SIP for the area before redesignation of 

the area as an attainment area. In this 

instance, the Las Vegas Valley PM10

Maintenance Plan does not provide for 

the repeal or relaxation of any of the 

measures that contributed to attainment 

of the PM10 standard in Las Vegas 

Valley, and thus, the plan need not 

provide for any such measures to be 

reinstituted as a contingency in the 

event of an exceedance of the NAAQS. 

Contingency provisions for 

maintenance plan purposes are 

distinguished from those generally 

required for nonattainment areas under 

section 172(c)(9) in that they are not 

required to be fully-adopted measures 

that will take effect without further 

action by the state in order for the 

maintenance plan to be approved. 

However, the contingency plan is 

considered to be an enforceable part of 

the SIP and should ensure that the 

contingency measures are adopted 

expeditiously once they are triggered by 

a specified event. The maintenance plan 

should clearly identify the measures to 

be adopted, a schedule and procedure 

for adoption and implementation, and a 

specific timeline for action by the State. 

As a necessary part of the plan, the State 

should also identify specific indicators 

or triggers, which will be used to 

determine when the contingency 

measures need to be implemented. 

As required by section 175A of the 

CAA, Clark County has adopted a 

contingency plan to address possible 

future PM10 air quality problems. See 

section 6.9 of the Las Vegas Valley PM10

Maintenance Plan. As described in 

section 6.9 of the maintenance plan, 

Clark County DAQ intends to rely on its 

continuous ambient PM10 monitoring 

network to track PM10 concentrations 

and has selected a confirmed violation 

of the PM10 NAAQS, defined as more 

than one expected exceedance per year 

averaged over a three-year period, as the 

primary triggering mechanism. Clark 

County DAQ refers to the date sixty 

days from such a violation as the trigger 

date after which the contingency plan 

would go into effect. 

Under the contingency plan, within 

45 days of the trigger date, Clark County 

DAQ would notify EPA that an internal 

review process has begun to evaluate 

potential contingency measures. The list 

of potential contingency measures, not 

intended to be inclusive, includes: 

(1) Implementing a new dust control 

permit requirement for short-term 

activities that disturb or have the 

potential to disturb soils that emit PM10, 

such as mechanized weed abatement, 

fair, carnivals, Christmas tree and 

Halloween pumpkin lots, art sales; 

(2) Conducting a comprehensive 

review and update of Clark County’s 

Construction Activities Dust Control 

Handbook to increase the effectiveness 

of existing Best Management Practices 

(BMPs) and to identify new BMPs. 

Examples include: new management 

practices for soil-disturbing activities 

and practices for roadway and detention 

basin maintenance activities; 

(3) Reviewing dust mitigation plan 

requirements in Clark County Rule 90 

and 92, focusing on reducing acreagetrigger thresholds, incorporating 

additional mitigation plan criteria and 

lowering applicability thresholds for 

unpaved parking lots; 

(4) Reassigning staff to provide 

additional field enforcement of the air 

quality regulations that control sources 

of fugitive dust emissions; 

(5) Mapping construction activities 

during inspections to collect PM10 data 

to provide greater accuracy for 

calculating emissions from these 

activities; 

(6) Developing a new dust control 

database to strengthen oversight of dust 

control permits and improve 

compliance; and 


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31Transportation-related emissions of volatile 

organic compounds (VOC) and/or oxides of 

nitrogen (NOX) emissions must also be specified in 

PM10 areas if EPA or the state finds that 

transportation-related emissions of one or both of 

these precursors within the nonattainment area are 

a significant contributor to the PM10 nonattainment 

problem and has so notified the metropolitan 

planning organization (MPO) and the U.S. 

Department of Transportation (DOT), or if the 

applicable SIP revision or SIP revision submittal 

establishes an approved or adequate budget for such 

emissions as part of the RFP, attainment or 

maintenance strategy. 40 CFR 93.102(2)(iii). Neither 

of these conditions apply to the Las Vegas Valley 

PM10 nonattainment area, and thus, the Las Vegas 

Valley PM10 Maintenance Plan establishes MVEBs 

only for PM10, not for PM10 precursors. 

(7) Amending fugitive dust 

regulations to incorporate new 

technologies and measure for 

controlling emissions and prevent them 

from crossing property lines or causing 

a nuisance. 

Within 90 days of the notification to 

EPA, Clark County DAQ has committed 

to send EPA an informational report 

outlining recommended actions. Clark 

County DAQ will then solicit public 

involvement and Clark County Board of 

Commissioners and/or the State 

Environmental Commission will hold 

public hearings, as necessary, to 

consider recommended contingency 

measures. Under the contingency plan, 

the selected contingency measures must 

be adopted and implemented within 18 

months of the submittal of the 

informational report to EPA. 

Based on our understanding of the 

contingency plan, as summarized above, 

we find that the contingency provisions 

of the Las Vegas Valley PM10

Maintenance Plan clearly identify 

specific contingency measures, contain 

tracking and triggering mechanisms to 

determine when contingency measures 

are needed, contain a description of the 

process of recommending and 

implementing contingency measures, 

and contain specific timelines for 

action. Thus, we conclude that the 

contingency provisions of the Las Vegas 

Valley PM10 Maintenance Plan are 

adequate to ensure prompt correction of 

a violation and therefore comply with 

section 175A(d) of the Act. 

6. Subsequent Maintenance Plan 

Revisions 

CAA section 175A(b) provides that 

States shall submit a SIP revision 8 

years after redesignation providing for 

maintaining the NAAQS for an 

additional 10 years. The Las Vegas 

Valley PM10 Maintenance Plan includes 

a commitment to prepare and submit a 

revised maintenance plan eight years 

after redesignation to attainment. See 

section 6.10 of the Las Vegas Valley 

PM10 Maintenance Plan. 

7. Motor Vehicle Emissions Budgets 

Transportation conformity is required 

by section 176(c) of the CAA. Our 

transportation conformity rule (codified 

in 40 CFR part 93, subpart A) requires 

that transportation plans, programs, and 

projects conform to SIPs and establishes 

the criteria and procedures for 

determining whether or not they do so. 

Conformity to the SIP means that 

transportation activities will not 

produce new air quality violations, 

worsen existing violations, or delay 

timely attainment of the national 

ambient air quality standards. 

PM10 maintenance plan submittals 

must specify the maximum emissions of 

transportation-related PM10 emissions 31

allowed in the last year of the 

maintenance period, i.e., the motor 

vehicle emissions budgets (MVEBs). 

(MVEBs may also be specified for 

additional years during the maintenance 

period.) The MVEBs serve as a ceiling 

on emissions that would result from an 

area’s planned transportation system. 

The MVEB concept is further explained 

in the preamble to the November 24, 

1993, transportation conformity rule (58 

FR 62188). The preamble describes how 

to establish MVEBs in the SIP and how 

to revise the MVEBs if needed. 

The maintenance plan submittal must 

demonstrate that these emissions levels, 

when considered with emissions from 

all other sources, are consistent with 

maintenance of the NAAQS. In order for 

us to find these emissions levels or 

‘‘budgets’’ adequate and approvable, the 

submittal must meet the conformity 

adequacy provisions of 40 CFR 

93.118(e)(4) and (5). For more 

information on the transportation 

conformity requirement and applicable 

policies on MVEBs, please visit our 

transportation conformity Web site at: 

http://www.epa.gov/otaq/

stateresources/transconf/index.htm. 

EPA’s process for determining 

adequacy of a MVEB consists of three 

basic steps: (1) Notifying the public of 

a SIP submission; (2) providing the 

public the opportunity to comment on 

the MVEB during a public comment 

period; and, (3) making a finding of 

adequacy or inadequacy. The process 

for determining the adequacy of a 

submitted MVEB is codified at 40 CFR 

93.118(f). 

On November 7, 2012, EPA 

announced the availability of the Las 

Vegas Valley PM10 Maintenance Plan 

with MVEBs and a 30-day public 

comment period on EPA’s Adequacy 

Web site at: http://www.epa.gov/otaq/

stateresources/transconf/currsips.htm. 

The comment period for this 

notification ended on December 7, 2012, 

and EPA received no comments from 

the public. Note, however, that a second 

mechanism is also provided for EPA 

review and public comment on MVEBs, 

as described in 40 CFR 93.118(f)(2). This 

mechanism provides for EPA’s review of 

the adequacy of an implementation plan 

MVEB simultaneously with its review 

and approval and/or disapproval of the 

applicable SIP revision itself. In this 

action, EPA used the web notification 

discussed above to solicit public 

comments on the adequacy of Clark 

County’s MVEBs, but is taking comment 

on the approvability of the submitted 

MVEBs through this proposed rule. 

The Las Vegas Valley PM10

Maintenance Plan contains design-day 

PM10 MVEBs for the BLM disposal area 

portion of the Las Vegas Valley PM10

nonattainment area for the last year of 

the maintenance period (2023), as well 

as the 2008 base year (attainment 

inventory) and an interim year (2015). 

Table 3 presents the MVEBs from the 

Las Vegas Valley PM10 Maintenance 

Plan and shows how they are derived. 

Specifically, the MVEBs represent the 

sum of certain source categories or 

subcategories from the emissions 

inventories prepare for the Las Vegas 

Valley PM10 Maintenance Plan plus a 

safety margin. The applicable source 

categories or subcategories included in 

the MVEBs include vehicle emissions 

(including exhaust, brake wear, and tire 

wear), paved road dust, unpaved road 

dust, and three construction-related 

source subcategories (road construction 

dust, construction track-out, and wind 

erosion associated with road 

construction). The safety margins 

represent the difference between the 

sum of the emissions from the source 

categories or subcategories described 

above and the PM10 MVEB currently in 

effect in Las Vegas Valley under the 

approved Las Vegas Valley PM10

Attainment Plan (i.e., 141.41 tons per 

day). 


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32AP–42, Compilation of Air Pollutant Emission 

Factors, is the primary compilation of EPA’s 

emission factor information. It contains emission 

factors and process information for more than 200 

air pollution source categories, including paved 

roads. EPA released an update to AP–42 in January 

of 2011, which revised the equation for estimating 

paved road dust emissions based on an updated 

regression that included new emission tests results. 

Clark County DAQ used the updated AP–42 

equation with local data on vehicle weight and silt 

loading data collected in 2003–2006 with Vehicle 

Miles Traveled (VMT) data from RTC’s TransCAD 

model to estimate paved road emissions. 

33See EPA memorandum dated October 28, 2013 

titled, ‘‘Adequacy Documentation for Plan Motor 

Vehicle Emission Budgets in August 2012 Clark 

County PM10 Maintenance State Implementation 

Plan.’’ 

TABLE 3—MOTOR VEHICLE EMISSIONS BUDGETS IN THE LAS VEGAS VALLEY PM10 MAINTENANCE PLAN

Category 

Design-day emissions 

(PM10, tons per day) a

2008 2015 2023 

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

Paved Road Dust .................................................................................................................................... 30.85 38.04 48.78 

Unpaved Road Dust (public) ................................................................................................................... 0.28 0.32 0.36 

Road Construction Dust .......................................................................................................................... 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 

Subtotals ........................................................................................................................................... 42.53 50.78 63.12 

Safety Margin ........................................................................................................................................... 98.88 90.63 78.29 

Totals ......................................................................................................................................... 141.41 141.41 141.41 

a Corresponds to the BLM disposal area portion of Las Vegas Valley. 

Source: Derived from tables 7–1, 7–2, and 7–3 in section 7.0 in the Las Vegas Valley PM10 Maintenance Plan. 

The MVEBs in the Las Vegas Valley 

PM10 Maintenance Plan reflect: (1) Onroad motor vehicle emission factors 

from EPA’s current motor vehicle 

emissions factor model (MOVES); (2) 

fugitive paved and unpaved road and 

road construction emission factors from 

Compilation of Air Pollutant Emission 

Factors (AP–42); 32 and (3) updated 

vehicle activity data from the Regional 

Transportation Commission of Southern 

Nevada’s (RTC’s) Clark County ActivityBased Travel Demand Simulation Model 

(TransCAD) transportation modeling 

system. 

As described above, the Las Vegas 

Valley PM10 Maintenance plan uses a 

2008 attainment-year emissions 

inventory to project emissions to 2015 

and 2023 and show continually 

decreasing emissions, thereby 

demonstrating maintenance of the 

NAAQS through 2023. As shown in 

table 2 of this document, the Las Vegas 

Valley PM10 Maintenance Plan estimates 

that design-day emissions in the BLM 

disposal area portion of the Las Vegas 

PM10 nonattainment area will decrease 

from approximately 710 tons per day in 

2008 to approximately 600 tons per day 

in 2015 and will then further decrease 

to approximately 490 tons per day in 

2023. 

A state may choose to apply a safety 

margin under our transportation 

conformity rule so long as such margins 

are explicitly quantified in the 

applicable plan and are shown to be 

consistent with attainment or 

maintenance of the NAAQS (whichever 

is relevant to the particular plan). See 40 

CFR 93.124(a). For the Las Vegas Valley 

PM10 Maintenance Plan, Clark County 

DAQ increased the motor vehicle 

related emissions estimates (i.e., 

vehicle, paved and unpaved road dust, 

construction track-out, and road 

construction (including related wind 

erosion) to equal 141.41 tons per day, 

which is the 2006 attainment-year 

MVEB approved in connection with the 

Las Vegas Valley PM10 Attainment Plan. 

The Las Vegas Valley PM10 Maintenance 

Plan demonstrates continued 

maintenance with the additional safety 

margins by showing that, with the safety 

margins added to the estimates for 2015 

and 2023, the overall emissions in 2015 

(694.35 tons per day) and 2023 (563.53 

tons per day) would still be less than the 

emissions inventory for the attainment 

year 2008 (706.55 tons per day). See 

table 7–3 of the Las Vegas Valley PM10

Maintenance Plan. 

EPA is proposing to approve the 

MVEBs for 2008, 2015 and 2023, shown 

in table 3 above, as part of our approval 

of Las Vegas Valley PM10 Maintenance 

Plan. EPA has determined that the 

MVEB emission targets are consistent 

with emission control measures in the 

SIP and are consistent with 

maintenance of the 24-hour PM10

standard in Las Vegas Valley through 

2023. The details of EPA’s evaluation of 

the MVEBs for compliance with the 

budget adequacy criteria of 40 CFR 

93.118(e) are provided in a separate 

memorandum 33 included in the docket 

of this rulemaking. Because the budgets 

EPA approved in 2004 are the same 

level as the budgets EPA is proposing to 

approve in this action, if EPA approves 

the MVEBs in the final rulemaking 

action, it would not change the budgets 

currently in use for transportation 

conformity determinations for Clark 

County. Any and all comments on the 

approvability of the MVEBs should be 

submitted during the comment period 

stated in the DATES section of this 

document. 

VI. Evaluation of Revisions to Clark 

County Fugitive Dust Rules 

As noted above, the Las Vegas Valley 

PM10 Maintenance Plan relies on the 

continued application of the county’s 

fugitive dust rules, particularly sections 

90 through 94; however, these rules, 

with the exception of section 94, as 

approved into the SIP, apply within the 

‘‘PM10 nonattainment area 

(hydrographic basin 212).’’ Section 94 

applies county-wide, not just in the 

PM10 nonattainment area. Redesignation 

of the Las Vegas Valley PM10

nonattainment area to attainment, as 

proposed herein, could undermine 

continued applicability and 

enforceability of the rules. To address 

this issue, the Clark County Board of 

County Commissioners recently adopted 

revisions to the rules to clarify their 

continued applicability within both a 

‘‘PM10 nonattainment area’’ and an 

‘‘area subject to a PM10 maintenance 

plan.’’ 

Clark County section 90 specifies 

requirements and measures to be 

implemented within the nonattainment 

area (and Apex Valley) for control of 

fugitive dust emissions from open areas 

and vacant lots. Section 91 specifies 

requirements and measures to be 

implemented within the nonattainment 

area (and Apex Valley) for control of 


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34As amended on April 15, 2014, section 41 (see 

subsection 41.2.3) continues to include outdated 

references to Clark County section 15, which was 

replaced by section 12 a number of years ago. We 

recommend that Clark County update section 41 

with the correct references to the appropriate 

subsections of section 12. 

35CAA section 110(l) provides, in relevant part, 

that EPA shall not approve a SIP revision if the SIP 

revision would interfere with any applicable 

requirement concerning attainment and reasonable 

further progress, or any other applicable 

requirement of the CAA. 

fugitive dust from unpaved roads, 

unpaved alleys, and unpaved easement 

roads. Section 92 specifies requirements 

and measures to be implemented within 

the nonattainment area (and Apex 

Valley) for control of fugitive dust from 

unpaved parking lots, material handling 

and storage yards, and vehicle and 

equipment storage yards, not otherwise 

regulated under Clark County section 94 

(‘‘Permitting & Dust Control for 

Construction Activities’’). Section 93 

specifies requirements and measures to 

be implemented within the 

nonattainment area (and Apex Valley) 

for control of fugitive dust from paved 

roads and street sweeping equipment. 

EPA most recently approved section 

90 at 71 FR 63250 (October 30, 2006); 

section 91 at 69 FR 32272 (June 9, 2004), 

section 92 at 71 FR 63250 (October 30, 

2006); and section 93 at 71 FR 63250 

(October 30, 2006). Relative to the 

existing SIP versions, as discussed 

above, the rules have been amended to 

ensure that the rules continue to apply 

once the area is redesignated to 

attainment for PM10. The rules have also 

been amended to reflect changes in the 

name of the county’s air pollution 

control district and to use the term 

‘‘hydrographic area’’ instead of 

‘‘hydrographic basin.’’ Lastly, Clark 

County has amended section 92 to add 

an exemption from the paving 

requirement for new equestrian staging 

areas so long as the applicable 

performance standards in the rule are 

met. We find that these changes 

generally improve the SIP as well as 

providing the necessary support for the 

Las Vegas PM10 Maintenance Plan. 

Moreover, we find that the limited and 

qualified exemption from the paving 

requirement under Clark County section 

92 for new equestrian staging areas 

would have no effect on continued 

maintenance of the PM10 standard in 

Las Vegas Valley and is acceptable. 

NDEP’s May 27, 2014 SIP revision 

submittal of amended Clark County 

fugitive dust rules also includes an 

amended version of section 41 

(‘‘Fugitive dust’’). The most recent 

approval by EPA of Clark County 

section 41 was at 46 FR 43141 (August 

27, 1981). This older fugitive dust rule 

establishes general fugitive dust 

requirements and measures applicable 

throughout Clark County but that are 

largely superseded with respect to 

construction activities by section 94 

and, within the PM10 nonattainment 

area (and Apex Valley), by the specific 

measures and other requirements in 

sections 90 through 93. Section 41 also 

contains certain provisions related to 

off-road vehicle and motocross racing 

that apply only within the 

nonattainment area. The recent 

amendments adopted by the Clark 

County Board of County Commissioners 

ensure the continued applicability of 

the off-road vehicle and motocrossrelated provisions once the area is 

redesignated to attainment. Other 

changes relative to the SIP version 

include the deletion of provisions 

addressing vacant lots from which 

topsoil was removed prior to 1973 and 

the addition of provisions intended to 

clarify the conditions that the rule seeks 

to avoid through application of 

‘‘reasonable precautions.’’ Within Las 

Vegas Valley and Apex Valley, vacant 

lots are now addressed by the specific 

measures and other requirements in 

Clark County section 90. The other 

changes in section 41 generally improve 

the SIP as well as provide support for 

the Las Vegas Valley PM10 Maintenance 

Plan.34

Therefore, for the reasons discussed 

above, we find that Clark County 

fugitive dust rules sections 90 through 

93, and 41, as amended by the Clark 

County Board of County Commissioners 

on April 15, 2014 (effective April 29, 

2014) and submitted by NDEP on May 

27, 2014, would not interfere with 

attainment or maintenance of any of the 

NAAQS and would provide necessary 

support for the Las Vegas Valley PM10

Maintenance Plan, and thus are 

approvable under CAA section 110(l).35

As such, we propose to approve the 

amended Clark County fugitive dust 

rules as a revision to the Nevada SIP. 

VII. Proposed Deletion of TSP 

Designation for Las Vegas Valley 

A. General Considerations 

Consistent with section 107(d)(4)(B), 

we have considered the continued 

necessity for retaining the remaining 

TSP area designations in Nevada, and as 

discussed below, we have decided that 

the TSP nonattainment designation for 

Las Vegas Valley (HA #212) is no longer 

necessary. As a result, we are proposing 

to delete it from the TSP table in 40 CFR 

81.329. 

To evaluate whether the TSP area 

designation should be retained or can be 

deleted, we have relied upon the final 

rule implementing the PM10 NAAQS 

(see 52 FR 24634, July 1, 1987), a policy 

memorandum on TSP redesignations 

(see memo dated May 20, 1992 from 

Joseph W. Paisie, Acting Chief, SO2/

Particulate Matter Programs Branch, 

EPA Office of Air Quality Planning and 

Standards, to Chief, Air Branch, Regions 

I–X, entitled ‘‘TSP Redesignation 

Request’’), and our proposed and final 

rules establishing maximum allowable 

increases in concentrations (also known 

as ‘‘increments’’) for PM10 (see the 

proposed rule at 54 FR 41218, October 

5, 1989, and the final rule at 58 FR 

31622, June 3, 1993). 

Based on the above references, we 

believe that the relevant considerations 

for evaluating whether the necessity of 

retaining the TSP area designations 

depend upon the status of a given area 

with respect to TSP and PM10. For areas 

that are nonattainment for TSP but 

attainment for PM10, we generally find 

that the TSP designations are no longer 

necessary and can be deleted when EPA 

(1) approves a State’s revised PSD 

program containing the PM10

increments, (2) promulgates the PM10

increments into a State’s SIP where the 

State chooses not to adopt the 

increments on their own, or (3) 

approves a State’s request for delegation 

of PSD responsibility under 40 CFR 

52.21(u). See 58 FR 31622, at 31635 

(June 3, 1993). 

For areas that are nonattainment for 

TSP and nonattainment for PM10, an 

additional consideration is whether 

deletion of the TSP designations would 

automatically relax any emissions 

limitations, control measures or 

programs approved into the SIP. If such 

a relaxation would occur automatically 

with deletion of the TSP area 

designations, then we will not delete the 

designations until we are satisfied that 

the resulting SIP relaxation would not 

interfere with any applicable 

requirement concerning attainment, 

reasonable further progress (RFP), or 

maintenance of the NAAQS or any other 

requirement of the Clean Air Act in the 

affected areas. See section 110(l) of the 

Act. 

In the case of Las Vegas Valley, we 

believe that the considerations for both 

types of areas described above are 

relevant because although Las Vegas 

Valley is nonattainment for PM10, we 

are proposing to redesignate the area to 

attainment for PM10 in today’s action. 

Thus, we must take into account both 

the potential for relaxation that would 

be inconsistent with continued 

maintenance of the PM10 NAAQS as 

well as protection of the PM10

increments (as applies in areas 

designated attainment or unclassifiable). 


tkelley on DSK3SPTVN1PROD with PROPOSALS
42274 Federal Register / Vol. 79, No. 139 / Monday, July 21, 2014 / Proposed Rules 

36More recently, EPA has taken limited approval 

and limited disapproval of amendments to Clark 

County’s NSR regulations. 77 FR 64039 (October 18, 

2012). In our 2012 final rule, we identified a 

number of deficiencies in the Clark County’s NSR 

regulations, but none of these deficiencies relate 

directly to protection of the PM10 increments. 

B. Deletion of TSP Nonattainment Area 

Designation for Las Vegas Valley 

With respect to protection of the PM10

increments, the TSP nonattainment 

designations are no longer necessary in 

Las Vegas Valley because we have 

approved Clark County’s NSR 

regulations as satisfying the related PSD 

requirements. See 69 FR 54006 

September 7, 2004.36 We recognize that 

NDEP retains jurisdiction over certain 

types of sources in Clark County but 

note that EPA’s PSD pre-construction 

permit program promulgated at 40 CFR 

52.21 apply to those sources under a 

delegation agreement between NDEP 

and EPA. See 40 CFR 52.1485(b). 

To ensure that deletion of the TSP 

nonattainment designation for Las Vegas 

Valley would not result in any 

automatic relaxations in SIP emissions 

limitations, control measures or 

programs that would interfere with 

attainment, RFP or maintenance of the 

NAAQS (including PM10) or any other 

requirement of the Act, we reviewed the 

following portions of the Nevada SIP: 

• The TSP portions of the Las Vegas 

Valley Air Quality Implementation Plan 

(AQIP) adopted in response to the CAA, 

as amended in 1977; 

• State stationary source rules 

including NAC 445B.22017 (‘‘Visible 

emissions: Maximum opacity; 

determination and monitoring of 

opacity’’) and NAC 445B.2203 

(‘‘Emissions of particulate matter: Fuelburning equipment’’); 

• Clark County stationary source 

rules, including section 26 (‘‘Emission 

of visible air contaminants’’), section 27 

(‘‘Particulate matter from process weight 

rate’’), section 28 (‘‘Fuel burning 

equipment’’), section 30 

(‘‘Incinerators’’), and section 42 (‘‘Open 

burning’’); and 

• Clark County fugitive dust rules, 

including section 41 and sections 90 

through 94, as proposed for approval 

herein (see section VI of this document). 

Based on our review of the TSP 

provisions in the Las Vegas Valley AQIP 

and the various rules cited above, we 

find that none are contingent upon 

continuation of the TSP nonattainment 

designations, and thus deletion of the 

TSP designations would not 

automatically relax any standard. More 

specifically: 

• The Las Vegas Valley AQIP relies 

primarily on fugitive dust controls, 

which are now codified in section 41 

and sections 90 through 94, and for 

which applicability does not depend on 

TSP designations; 

• State stationary source rules that 

apply to coal-fired power plants (i.e., 

the sources that fall under State 

jurisdiction in Clark County) contain 

percent opacity limits and PM10 limits 

for which the TSP designation is 

irrelevant; 

• Clark County stationary source 

rules sections 26, 27, 28, 30, and 42 do 

not contain requirements for which the 

TSP area designation is relevant; and 

• The applicability of the relevant 

portion of the Clark County rule section 

41 (‘‘Fugitive dust’’) and the other 

county fugitive dust rules sections 90 

through 94 are expressed in terms of the 

designated boundaries of the PM10

nonattainment area (or area subject to a 

PM10 maintenance plan), and not in 

terms of the boundaries of the TSP area. 

In summary, because the PSD PM10

increments apply in Las Vegas Valley 

and because the deletion of the TSP 

nonattainment designation for Las Vegas 

Valley would not automatically relax 

any emissions limitation or control 

measure in the Nevada SIP, we find that 

the TSP nonattainment designation is 

no longer necessary and can be deleted. 

Based on the above discussion and 

evaluation, therefore, we are proposing 

to delete the TSP nonattainment area 

designation for Las Vegas Valley (HA 

#212) from the ‘‘Nevada-TSP’’ table in 

40 CFR 81.329. 

VIII. Proposed Action and Request for 

Public Comment 

Under CAA section 110(k)(3), and for 

the reasons set forth above, the EPA is 

proposing to approve NDEP’s submittal 

dated September 7, 2012 of the 

Redesignation Request and 

Maintenance Plan for Particulate Matter 

(PM10), Clark County, Nevada (August 

2012) (‘‘Las Vegas Valley PM10

Maintenance Plan’’) as a revision to the 

Nevada SIP. The EPA finds that the 

maintenance demonstration showing 

how the area will continue to attain the 

24-hour PM10 NAAQS for 10 years 

beyond redesignation, and the 

contingency provisions describing the 

actions that Clark County will take in 

the event of a future monitored 

violation, meet all applicable 

requirements for maintenance plans and 

related contingency provisions in CAA 

section 175A. The EPA is also proposing 

to approve the motor vehicle emissions 

budgets in the Las Vegas Valley PM10

Maintenance Plan (i.e., 141.14 tons per 

day in 2008, 2015, and 2023) because 

we find they meet the applicable 

transportation conformity requirements 

under 40 CFR 93.118(e). 

Second, under CAA section 

107(d)(3)(D), we are proposing to 

approve NDEP’s request, which 

accompanied the submittal of the 

maintenance plan, to redesignate the 

Las Vegas Valley PM10 nonattainment 

area to attainment for the 24-hour PM10

NAAQS. We are doing so based on our 

conclusion that the area has met the five 

criteria for redesignation under CAA 

section 107(d)(3)(E). Our conclusion in 

this regard is in turn based on our 

proposed determination that the area 

has attained the 24-hour PM10 NAAQS, 

that relevant portions of the Nevada SIP 

are fully approved, that the 

improvement in air quality is due to 

permanent and enforceable reductions 

in emissions, that Nevada has met all 

requirements applicable to the Las 

Vegas Valley PM10 nonattainment area 

with respect to section 110 and part D 

of the CAA, and based on our proposed 

approval as part of this action of the Las 

Vegas Valley PM10 Maintenance Plan. 

Our proposed determination that the 

area has attained the 24-hour PM10

NAAQS is based in part on our 

concurrence with Clark County DAQ 

that the exceedances monitored in Las 

Vegas Valley on July 3, 2011 were 

caused by a high wind exceptional 

event and our related exclusion of the 

exceedances from the attainment 

determination. 

Third, EPA is proposing to approve 

revisions to Clark County fugitive dust 

rules sections 41, and 90 through 93 that 

were submitted on May 27, 2014 as a 

revision to the Nevada SIP because we 

find that they ensure continued 

implementation of the rules after 

redesignation of Las Vegas Valley to 

attainment and because they meet all 

other applicable requirements. 

Proposing to do so is consistent with the 

assumptions upon which the 

maintenance plan is based. 

Lastly, EPA is proposing to delete the 

area designation for Las Vegas Valley for 

the revoked national standard for total 

suspended particulate because the 

designation is no longer necessary. 

EPA is soliciting public comments on 

the issues discussed in this document or 

on other relevant matters. We will 

accept comments from the public on 

this proposal for the next 30 days. We 

will consider these comments before 

taking final action. 

IX. Statutory and Executive Order 

Reviews 

Under the CAA, redesignation of an 

area to attainment and the 

accompanying approval of a 

maintenance plan under section 

107(d)(3)(E) are actions that affect the 

status of a geographical area and do not 


tkelley on DSK3SPTVN1PROD with PROPOSALS
Federal Register / Vol. 79, No. 139 / Monday, July 21, 2014 / Proposed Rules 42275 

impose any additional regulatory 

requirements on sources beyond those 

imposed by State law. Redesignation to 

attainment does not in and of itself 

create any new requirements, but rather 

results in the applicability of 

requirements contained in the CAA for 

areas that have been redesignated to 

attainment. Moreover, the Administrator 

is required to approve a SIP submission 

that complies with the provisions of the 

Act and applicable Federal regulations. 

42 U.S.C. 7410(k); 40 CFR 52.02(a). 

Thus, in reviewing SIP submissions, 

EPA’s role is to approve State choices, 

provided that they meet the criteria of 

the Clean Air Act. Accordingly, these 

actions merely propose to approve a 

State plan and redesignation request as 

meeting Federal requirements and do 

not impose additional requirements 

beyond those by State law. For these 

reasons, these proposed actions: 

• Are not a ‘‘significant regulatory 

action’’ subject to review by the Office 

of Management and Budget under 

Executive Order 12866 (58 FR 51735, 

October 4, 1993) and Executive Order 

13563 (76 FR 3821, January 21, 2011); 

• Do not impose an information 

collection burden under the provisions 

of the Paperwork Reduction Act (44 

U.S.C. 3501 et seq.); 

• Are certified as not having a 

significant economic impact on a 

substantial number of small entities 

under the Regulatory Flexibility Act (5 

U.S.C. 601 et seq.); 

• Do not contain any unfunded 

mandate or significantly or uniquely 

affect small governments, as described 

in the Unfunded Mandates Reform Act 

of 1995 (Pub. L. 104–4); 

• Do not have Federalism 

implications as specified in Executive 

Order 13132 (64 FR 43255, August 10, 

1999); 

• Are not an economically significant 

regulatory action based on health or 

safety risks subject to Executive Order 

13045 (62 FR 19885, April 23, 1997); 

• Are not a significant regulatory 

action subject to Executive Order 13211 

(66 FR 28355, May 22, 2001); 

• Are not subject to requirements of 

Section 12(d) of the National 

Technology Transfer and Advancement 

Act of 1995 (15 U.S.C. 272 note) because 

application of those requirements would 

be inconsistent with the CAA; and 

• Do not provide EPA with the 

discretionary authority to address 

disproportionate human health or 

environmental effects with practical, 

appropriate, and legally permissible 

methods under Executive Order 12898 

(59 FR 7629, February 16, 1994). 

In addition, this proposed rule does 

not have Tribal implications as 

specified by Executive Order 13175 (65 

FR 67249, November 9, 2000), because 

the SIP is not approved to apply in 

Indian country located in the State, and 

EPA notes that it will not impose 

substantial direct costs on Tribal 

governments or preempt Tribal law. 

Nonetheless, EPA has discussed the 

proposed action with the one Tribe, the 

Las Vegas Paiute Tribe, located within 

the Las Vegas Valley PM10

nonattainment area. 

List of Subjects 

40 CFR Part 52 

Environmental protection, Air 

pollution control, Intergovernmental 

relations, Nitrogen dioxide, Particulate 

matter, Reporting and recordkeeping 

requirements, Sulfur dioxide. 

40 CFR Part 81 

Environmental protection, Air 

pollution control, National parks, 

Wilderness areas. 

Dated: June 27, 2014. 

Alexis Strauss, 

Acting Regional Administrator, Region IX. 

[FR Doc. 2014–16575 Filed 7–18–14; 8:45 am] 

BILLING CODE 6560–50–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 61 

[EPA–HQ–OAR–2008–0218; FRL–9914–06– 

OAR] 

RIN 2060–AP26 

Revisions to National Emission 

Standards for Radon Emissions From 

Operating Mill Tailings 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Proposed rule; extension of 

comment period. 

SUMMARY: The Environmental Protection 

Agency is announcing an extension of 

the public comment period for the 

Notice of Proposed Rulemaking (NPRM) 

requesting public comment and 

information on revisions to the EPA’s 

‘‘National Emission Standards for Radon 

Emissions from Operating Mill 

Tailings’’. The EPA published the 

NPRM on May 2, 2014 in the Federal 

Register, which included a request for 

comments on or before July 31, 2014. 

The purpose of this action is to extend 

the public comment period an 

additional 90 days. 

DATES: Written comments on the 

proposed rule published on May 2, 2014 

(79 FR 25388) must be received on or 

before October 29, 2014. 

ADDRESSES: Submit your comments, 

identified by Docket ID No. EPA–HQ– 

OAR–2008–0218, by one of the 

following methods: 

• www.regulations.gov: Follow the 

on-line instructions for submitting 

comments. 

• Email: a-and-r-docket@epa.gov. 

• Fax: (202) 566–9744. 

• Mail: U.S. Postal Service, send 

comments to: Air and Radiation Docket, 

EPA Docket Center, Docket ID No. EPA– 

HQ–OAR–2008–0218, 1200 

Pennsylvania Ave. NW., Washington, 

DC 20460. Please include a total of two 

copies. 

Hand Delivery: In person or by 

courier, deliver comments to: EPA 

Docket Center, Docket ID No. EPA–HQ– 

OAR–2008–0218, EPA West, Room 

3334, 1301 Constitution Avenue NW., 

Washington, DC 20004. Such deliveries 

are only accepted during the Docket’s 

normal hours of operation, and special 

arrangements should be made for 

deliveries of boxed information. Please 

include a total of two copies. 

Instructions: Direct your comments to 

Docket ID No. EPA–HQ–OAR–2008– 

0218. The Agency’s policy is that all 

comments received will be included in 

the public docket without change and 

may be made available online at 

www.regulations.gov, including any 

personal information provided, unless 

the comment includes information 

claimed to be Confidential Business 

Information (CBI) or other information 

whose disclosure is restricted by statute. 

Do not submit information that you 

consider to be CBI or otherwise 

protected through www.regulations.gov 

or email. The www.regulations.gov Web 

site is an ‘‘anonymous access’’ system, 

which means EPA will not know your 

identity or contact information unless 

you provide it in the body of your 

comment. If you send an email 

comment directly to EPA without going 

through www.regulations.gov your email 

address will be automatically captured 

and included as part of the comment 

that is placed in the public docket and 

made available on the Internet. If you 

submit an electronic comment, EPA 

recommends that you include your 

name and other contact information in 

the body of your comment and with any 

disk or CD–ROM you submit. If EPA 

cannot read your comment due to 

technical difficulties and cannot contact 

you for clarification, EPA may not be 

able to consider your comment. 

Electronic files should avoid the use of 

special characters, any form of 

encryption, and be free of any defects or 

viruses. For additional information 

about the EPA’s public docket, visit the 


tkelley on DSK3SPTVN1PROD with PROPOSALS