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State Implementation Plans
SIP-Related Documents
The U.S. Environmental Protection Agency (EPA) develops National Ambient Air Quality Standards (NAAQS) to protect human health and the environment. DAQ is required to develop long-term planning documents such as State Implementation Plans (SIPs) to demonstrate how the NAAQS will be achieved, maintained, and enforced. After an area reaches attainment, a Redesignation Request and Maintenance Plan is developed to demonstrate maintenance for at least the next 10-year period. These SIPs and Maintenance Plans become the Clark County portion of the Nevada SIP. DAQ also develops Transportation Conformity Plans, in collaboration with the Regional Transportation Commission of Southern Nevada (RTC), the MPO for Clark County, to address transportation conformity issues in Southern Nevada.
Currently, the Las Vegas Valley (Hydrographic Area 212) is classified as moderate nonattainment for the 2015 Ozone (O3) NAAQS. Hydrographic Area 212 is an attainment area subject to a maintenance plan for the CO and PM10 NAAQS. Hydrographic Areas 164A, 164B, 165, 166, 167, 212, 213, 214, 216, 217, and 218 (excluding the Moapa River Indian Reservation and the Fort Mohave Indian Reservation) are attainment areas subject to a maintenance plan for the 1997 O3 NAAQS. Click here for a map detailing Clark County's area designations.
Particulate Matter (PM10)
The Las Vegas Valley (HA 212) within Clark County is a maintenance area for PM10. DAQ submitted a Redesignation Request and Maintenance Plan in August 2012. On October 6, 2014, EPA approved our request and designated Clark County as an attainment area, effective November 5, 2014.
DAQ submitted a SIP in 2001, which explains how the area will attain the NAAQS for PM10. The plan is the cumulative program of all pollution control strategies, control measures, emission inventories, attainment demonstration, and state statute and local rules implemented. Final EPA approval of the plan was effective July, 2004.
Subsequently, DAQ submitted a Milestone Achievement Report (MAR) in June 2007. The MAR documents Clark County’s attainment of the 24-hour PM10 NAAQS. On August 3, 2010, EPA made the determination that the Las Vegas Valley was in attainment with the PM10 NAAQS (75 FR 45485), and the area was redesignated to attainment with the approval of the maintenance plan and designation request in October 2014.
App A - Technical Support Document
App B - Documentation of the Public Review Process
79 FR 42258: EPA Notice of Proposed Approval (July 2014)
App A - Design Value Determination
App B - Emission Inventory Methodology
App C - Estimation of Valley-Wide PM10 Emissions
App D - PM10 Emissions Inventory of Sources Surrounding Monitoring Sites
App E - Inventory Projections Methodology and Calculations
App F - Control Measure Development Process
App G - Air Quality Regulations and Section 94 Handbook
App H - Clark County Health District Resolutions
App I - Letter from Nevada Department of Motor Vehicles and Public Safety
App J - Street Sweeping Equipment and Paved Road Cleanup Programs
App K - Rollback Methodology
App L - Controlled Emission Inventory Development
App M - Reasonable Further Progress Inventory of 2003
App N - Mobile Source Emissions Budget
App O - Public Review Process
App P - Comments Received
App Q - Public Hearing Documentation
App R - Residential Wood Combustion Control Measures
Carbon Monoxide (CO)
The Las Vegas Valley (HA 212) within Clark County is a maintenance area for CO. DAQ submitted a Redesignation Request and Maintenance Plan in 2008. On September 27, 2010, EPA approved our request and designated Clark County as an attainment area, effective September 27, 2010 (75 FR 59090).
DAQ submitted a SIP in 2000, describing the control measures and technologies to bring the Las Vegas Valley into compliance with the CO NAAQS. This plan was approved by EPA, effective October 21, 2004 (69 FR 56351). On June 1, 2005, EPA issued a determination of attainment for the Las Vegas Valley CO nonattainment area (70 FR 31353). A revision of the SIP was submitted in 2005 to update the CO emissions budgets using the latest model approved by EPA for transportation conformity determinations (MOBILE6). This revision was approved by EPA on August 7, 2006 (71 FR 44587).
Entire Document
App A - Letter from EPA, dated August 7, 2017
App B - Documentation of Public Review Process
NDEP Review of CO Limited Maintenance Plan and Recommendations to EPA
86 FR 41416: EPA Notice of Proposed Approval (August 2021)
App A - Wintertime Gasoline Spec Study
App B - Technical Support Document
App C - Public Review Process
NDEP Review of CO Maintenance Plan and Recommendations to EPA
Ozone (O3)
2015 O3 NAAQS
In September 2016, Clark County submitted its Area Designation Recommendations for the 2015 O3 NAAQS, recommending that only certain portions of the County be designated as nonattainment. On December 20, 2017, EPA issued its 120-day designations letter for the 2015 O3 NAAQS, identifying portions of the County to be designated as nonattainment. Subsequently, on February 23, 2018, Clark County, through the Nevada Division of Environmental Protection (NDEP), submitted a revised recommendation based on updated monitoring data. This revision requested that only the Las Vegas Valley (HA 212) be designated as nonattainment.
On June 4, 2018, EPA designated the Las Vegas Valley as a marginal nonattainment area for the 2015 O3 NAAQS, effective August 3, 2018 (83 FR 25776). Subsequently, on January 5, 2023, EPA issued a final rule determining that the Las Vegas Valley failed to attain the 2015 O3 NAAQS by the applicable marginal nonattainment deadline. The rule reclassified the area as a moderate nonattainment area and established a new attainment deadline of August 3, 2024 (88 FR 775). On October 18, 2023, EPA issued a final rule determining that the Las Vegas Valley failed to submit the required moderate nonattainment SIP by the submission deadline (88 FR 71757)
In November 2024, DAQ submitted an attainment SIP to address the planning requirements for areas classified as moderate nonattainment and resolve EPA's finding of failure to submit. The SIP includes the following elements: emission inventories, an attainment demonstration, nonattainment new source review, a 15% rate of progress, reasonably available control measures (RACM), reasonably available control technology (RACT), motor vehicle inspection and maintenance, contingency measures, and a motor vehicle emissions budget for transportation conformity.
On December 19, 2024, EPA issued a final rule determining that the Las Vegas Valley failed to attain the 2015 O3 NAAQS by the applicable moderate nonattainment deadline. As a result, EPA reclassified the area as a serious nonattainment area, effective January 21, 2025, and set a new attainment deadline of August 3, 2027 (89 FR 103657).
2008 O3 NAAQS
On May 21, 2012, EPA designated Clark County as attainment/unclassifiable for the 2008 O3 NAAQS, effective July 20, 2012 (77 FR 30088).
On June 12, 2013, DAQ enrolled in EPA's O3 Advance program, a collaborative effort between EPA and air agencies aimed at preserving air quality in O3 attainment areas. Participating agencies work with EPA to identify, evaluate, and implement measures and programs to reduce O3 and continue making improvements in air quality. Progress reports detailing program activities, achievements, and identifying future program goals are submitted on an annual basis.
1997 O3 NAAQS
An O3 Early Progress Plan that provides the basis for establishing early transportation conformity budgets for the Clark County 8-hour O3 nonattainment area was submitted to EPA in 2008, and approved in 2009. A Redesignation Request and Maintenance Plan for the 1997 8-hour O 3 NAAQS was submitted in April 2011. On January 8, 2013, EPA approved our request and the Clark County nonattainment area was redesignated to attainment for the 1997 8-hour O3 NAAQS, effective February 7, 2013.
(2024) Entire Document
2015 O3 NAAQS Attainment Plan for the Las Vegas Valley Moderate Nonattainment Area, Clark County, NV- without Attachments
Att A- Emissions Inventory
Att B- Attainment Demonstration Technical Support Document
Att C- Control Technique Guideline Reasonably Available Control Technology Analysis
Att D- Major Source Reasonably Available Control Technology Analysis
Att E- Reasonably Available Control Measure Analysis
Att F- Rate-of-Progress Emissions Inventory
Att G- Rate-of-Progress Technical Support Document
Att H- Inspection/Maintenance Program Effectiveness Study
Att I- Wildfire Atypical Events Analyses
Att J- Enhanced Vapor Recovery Report
Att K- Documentation of Public Review Process
NDEP Review of 2015 O3 NAAQS Moderate Attainment Plan and Recommendations to EPA
88 FR 88300 EPA Notice of Proposed Approval (December 2023)
(2021) Entire Document
App A- Technical Support Document
App B- Documentation of Public Review Process
NDEP Review of 1997 O3 Second Maintenance Plan and Recommendations to EPA
88 FR 88300 EPA Notice of Proposed Approval (December 2023)
App A- Documentation of Public Review Process
NDEP Review of NNSR SIP Revision and Recommendations to EPA
89 FR 7318 EPA Notice of Proposed Approval (February 2024)
App A- Technical Support Document
App B- Documentation of Public Review Process
NDEP Review of Emissions Inventory and Emissions Statement SIP Revision and Recommendations to EPA
87 FR 45657: EPA Notice of Final Approval of Emissions Statement (July 2022)
87 FR 35705: EPA Notice of Proposed Approval of Emissions Inventory (June 2022)
87 FR 68057: EPA Notice of Final Approval of Emissions Inventory (Nov 2022)
App A- Technical Support Document
App B - Documentation of Public Review Process
NDEP Review of MVEB SIP Revision and Recommendations to EPA
86 FR 43461: EPA Notice of Proposed Approval (August 2021)
App A - Technical Support Document
App B - Documentation of Public Review Process
NDEP Review of MVEB SIP Revision and Recommendations to EPA
App A - Technical Support Document
App B - EPA AQS Design Value Report 2006-2009
App C - Documentation of the Public Review Process
77 FR 67600: EPA Notice of Proposed Approval (November 2012)
App A - Consolidated Emissions Inventory
App B - Air Quality regulations
App C - 2005 CCROPS Study
App D - Public review Process
Infrastructure SIP
The Federal Clean Air Act requires States to prepare Infrastructure SIPs (I-SIP) any time EPA promulgates a new or revises an existing NAAQS and is required whether or not an area is in compliance with a new standard. In accordance with this requirement, Clark County prepares its portion of the I-SIP to demonstrate it has the programs in place to implement, maintain, and enforce the NAAQS. These I-SIPs become part of the Nevada I-SIP. The I-SIP addresses the following air quality program elements: permitting; air quality modeling; enforcement; ambient air monitoring; and, confirmation of adequate personnel, resources, and legal authorities.
The Sulfur Dioxide (SO2) NAAQS was revised in 2010 and the I-SIP was submitted to NDEP in May 2013 for inclusion as a revision to the Nevada SIP.
The O3 NAAQS was revised in 2008 and the I-SIP was submitted to NDEP in February 2013 for inclusion as a revision to the NV SIP. The O3 NAAQS was revised in 2015 and the I-SIP was submitted to NDEP in September 2018 for inclusion as a revision to the Nevada SIP.
The Nitrogen Dioxide (NO2) NAAQS was revised in 2010 and the I-SIP was submitted to NDEP in December 2012 for inclusion as a revision to the Nevada SIP.
The Lead (Pb) NAAQS was revised in 2008 and the I-SIP was submitted to NDEP in July 2012 for inclusion as a revision to the Nevada SIP.
In 2008, the Nevada Department of Environmental Protection (NDEP) submitted a consolidated I-SIP for the 1997 8-hour O3 NAAQS, and the 1997 and 2006 NAAQS for PM2.5. This was a joint effort between NDEP, Washoe County Health District, and DAQ. EPA published a proposed rule for approval of the I-SIP on August 3, 2012. The final rule was promulgated on October 23, 2012.
78 FR 64430: EPA Notice of Proposed Approval (October 2013)
https://ndep.nv.gov/air/planning-and-modeling/regulations-and-sip-development
77 FR 46361: EPA Notice of Proposed Approval (August 2012)
Transportation Conformity Plan
The Transportation Conformity Plan details consultation criteria, policies, and procedures that applicable local, state and federal agencies must follow when addressing transportation conformity issues within Clark County. DAQ updated the plan in 2008. In July 2008, EPA issued a finding that the Transportation Conformity Plan fulfilled the requirements in 40 CFR Part 51, Appendix V. Subsequently, EPA issued a direct final rule in November 2008.
For more information or questions about SIP documents, contact Araceli Pruett at (702) 455-3206.