Clark County is proposing a new Clark County Air Quality Rule (CCAQR), Section 120, that establishes and implements Reasonably Available Control Technology (RACT) demonstration and determination requirements for existing major stationary sources of NO_x and VOC.

For context, Clark County defines RACT as the lowest emissions limitation that a particular source is capable of meeting by the application of control technology that is reasonably available, considering technological and economic feasibility. In determining RACT, the following shall be considered:

• Energy and environmental impacts and costs;

• Cost effectiveness;

• Control technology in use by similar sources; and

• Technical feasibility.

In 2018, after the EPA lowered the primary and secondary 8-hour ozone national ambient air quality standard, the Las Vegas Valley (Hydrographic Area 212) was designated as marginal nonattainment, as the area did not meet the new standards. The Valley was required to attain the new standards by August 2021. In anticipation of being reclassified to moderate non-attainment, as the Valley was not able to meet the standards by the deadline, DAQ asked select major sources to participate in establishing major source RACT for their operations. In 2023, the Valley was officially classified as moderate non-attainment for ozone and required to attain the standard by August of 2024.

In response to the anticipated redesignation of the Las Vegas Valley (Hydrographic area 212) from moderate non-attainment to serious non-attainment for ozone in the Fall of 2024, in which the major source threshold for NO_x and VOC (Ozone precursors) will be lowered to 50 tons per year (tpy), Clark County DAQ is proposing that existing major stationary sources are subject to RACT requirements regardless of the previous RACT applicability. Any source that will be newly classified as a major source under the lower major source thresholds must submit a Title V operating permit application within 12 months of the reclassification date and will be subject to Section 120.

Section 120 outlines the affected sources and units subject to the RACT requirements. The affected sources are defined as any source required to comply with major source RACT for NO_x or VOC under Section 120, and an affected unit is defined as a unit at an affected source to which the RACT requirements apply. Notes on affected sources within the definition include:

• If the exhaust emissions from separate units are combined into a single duct or stack, those emission units (and their combined emissions) shall be treated as a single affected unit.
• For purposes of Section 120, insignificant activities, as determined in Section 12.5, shall not be considered affected units. Also, for the purposes of Section 120, no activities with a potential to emit (PTE) greater than 2 tons per year of NO_x or VOC individually, with no threshold for a combination of pollutants, shall be eligible to be determined insignificant activities.
• The notification required by Section 120 may include additional criteria for identifying an affected unit.

Section 120 includes major source RACT demonstration requirements that will detail how the affected sources and units will demonstrate the appropriate RACT requirements for NO_x and VOC emissions controls. The rule also allows for the option to permanently shut down an affected unit rather than submitting a major source RACT demonstration. If the shutdown is not immediate, the source may propose and support interim emissions limitations.

Section 120 includes a detailed description of the application process and outlines the responsibility of the control officer to make the RACT determination considering the demonstration submitted. Upon completion of a new RACT demonstration as part of the application, the newly issued permit will include RACT requirements. The new determinations and requirements will be incorporated into the Nevada State Implementation Plan so that Clark County can move towards demonstrating compliance with the ozone NAAQS.

If your operation or facility has the potential to emit more than 50 tons per year of NO_x or VOC and your facility is not currently a major source, new compliance, monitoring, recordkeeping or reporting requirements may be applicable on top of the additional RACT requirements discussed here. If your operation was already a major source for other criteria pollutants, you are still required under Section 120 to implement new RACT for NO_x and VOC. Trinity Consultants can assist in developing permit revisions for new major sources, strategic permitting to decrease emissions to avoid becoming a new non-attainment Title V source or developing RACT demonstrations.

The department contact for the draft Section 120 is Jennifer Lipkin, Principal Air Quality Specialist for Clark County Department of Environmental and Sustainability Division of Air Quality ([email protected]).

You can view the draft regulation or leave comments on DAQ’s website here. Public comment started on September 6, and will close on September 27th.

If you would like to discuss the new RACT requirements impacting these sectors and how they may impact your facility, please email Matt Tarnoff in Trinity’s Reno office or call him at 775.242.3400.