On December 19, 2024, the U.S. Environmental Protection Agency (EPA) reclassified the Las Vegas Valley (HA 212) to “serious” nonattainment under the 2015 ozone National Ambient Air Quality Standards (NAAQS). This change, effective January 21, 2025, has significant impacts for stationary sources operating in this area. Facilities that generate ozone precursor emissions, including volatile organic compounds (VOCs) and nitrogen oxides (NOX), will now face stricter permitting requirements.
Changes in Permitting Thresholds and Requirements
- Lowered Major Source Threshold: The potential-to-emit (PTE) threshold for being classified as a major source of VOC or NOX emissions has been lowered from 100 tons per year (tpy) to 50 tpy.
- Stricter Modification Standards: Any modification leading to an increase of 25 tpy or more of VOCs or NOX will now trigger Nonattainment New Source Review (NNSR), down from the previous 40 tpy threshold.
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Increased Offset Ratio: The emissions offset ratio for major sources undergoing NNSR has increased from 1.15:1 to 1.2:1. This means that for every ton of emissions added, the facility must reduce emissions elsewhere by 1.2 tons.
Impact on New and Existing Stationary Sources
1. Existing Major Sources (PTE >100 tpy of VOC and/or NOX)
Facilities with a potential to emit (PTE) over 100 tpy will be subject to NNSR if they undertake modifications resulting in a significant increase (25 tpy or more). Such modifications will require:
- Installation of Lowest Achievable Emission Rate (LAER) controls, which are the most stringent emissions limits achieved in practice, with no consideration for economic cost.
- Emission offsets at the new 1.2:1 ratio.
2. Existing Sources with a PTE Between 50–100 tpy
Facilities falling into this category must either:
- Reduce their PTE below 50 tpy by applying for a permit revision, allowing them to remain minor sources; or
- Apply for a Title V (major source) permit within 12 months of the effective date (by January 21, 2026). While simply obtaining a Title V permit does not require offsets or LAER, any future modifications increasing emissions by 25 tpy or more will trigger NNSR.
3. Existing Sources with a PTE Below 50 tpy
Facilities emitting less than 50 tpy of VOCs or NOx will not need to change their permit type. However, if future modifications push total PTE over the 50-tpy threshold, facilities must do the following:
- Increases (project emissions) below 50 tpy will require an Authority to Construct (AQR 12.4) application and a subsequent Title V permit.
- Increases (project emissions) exceeding 50 tpy will classify the facility as a new major source, triggering full NNSR requirements, including offsets and LAER.
4. Synthetic Minor Sources with PTE between 40–50 tpy of VOC and/or NOX
These facilities will be considered as “Synthetic Minor 80” (SM80) sources, subject to federally enforceable emissions caps and additional compliance obligations to ensure emissions remain below 50 tpy.
Next Steps for Affected Stationary Sources
Permitted stationary sources operating in Las Vegas Valley should take steps to assess their current emissions and permitting obligations. Facilities must determine if they need to reduce emissions, apply for permit revisions, or prepare for Title V applications. Modifications planned for 2025 and beyond should consider the increased stringency of NNSR requirements, including higher offset ratios and LAER controls.
Clark County Department of Air Quality (DAQ) encourages affected facilities to consult with permitting professionals and submit necessary applications well in advance of deadlines to avoid operational disruptions. If you would like to discuss these updated permitting requirements in the Las Vegas Valley and how they may impact your facility, please email Matthew Tarnoff in Trinity’s Reno office or call 775.242.3200. Staying compliant with these new regulations will be critical for continuing operation in the Las Vegas Valley.
For more information, facilities should refer to Clark County DAQ guidelines and regulatory updates regarding the serious nonattainment designation. A summary of these changes can be found on the
DAQ website.
DAQ Notice of Annual Fee Changes
DAQ has provided notice of the annual updates to its fee schedule. The updated fee schedule has taken effect as of January 30, 2025 and can be found on the
DAQ website. Invoices issued and payments received, whether online or in envelopes postmarked on Thursday, January 30, 2025, will be subject to the new fees.
