Understanding the Ozone Nonattainment Area Designation
Pinal County, particularly the areas of Apache Junction, Queen Valley, and San Tan Valley, has struggled with elevated ozone levels, primarily due to industrial activities, vehicular emissions, and regional climatic conditions. Starting with the 2008 National Ambient Air Quality Standards (NAAQS), a portion of Pinal County near the city of Apache Junction was classified as nonattainment for ozone, being located in the Phoenix-Mesa nonattainment area. Due to the nonattainment status, Pinal County Air Quality Control District (PCAQCD) implemented reasonably available control technology (RACT) standards intended to reduce nitrogen oxides (NOX) and volatile organic compounds (VOC) emissions, both precursors to atmospheric ozone formation. These RACT measures targeted surface coating operations and storage and loading of gasoline at gasoline dispensing facilities.
In October 2022, the EPA formally classified additional areas under PCAQCD jurisdiction as moderate nonattainment for the 2015 8-hour ozone NAAQS. These expanded areas included the areas surrounding Gold Canyon and San Tan valley, expanding the previous nonattainment to the South and East. Following the 2015 redesignation, PCAQCD is required to implement reasonably available control technology (RACT) measures throughout the ozone nonattainment. The targeted RACT measures are identical to the previously applicable measures; however, it is proposed that these RACT standards will be applicable to these additional portions of Pinal County.
Impacts on Businesses and Industries
The expansion of the ozone nonattainment area imposes new compliance and permitting responsibilities on businesses, particularly those involved in surface coating operations and gasoline dispensing facilities. Key implications include:
- Regulatory Oversight: Businesses in the expanded nonattainment zone must adhere to stricter emission controls, subjecting them to additional compliance and reporting requirements.
- Operational Costs: Upgrading equipment to meet RACT standards may necessitate capital and operating expenditure.
- Increased Monitoring: Enhanced recordkeeping and emissions monitoring will be required to ensure compliance with state and federal air quality regulations.
Proposed RACT Measure Updates
As discussed previously, to address ozone pollution PCAQCD has proposed the implementation of RACT for two primary sectors: surface coating operations and gasoline dispensing facilities. These measures are aimed at reducing VOC emissions, which are significant contributors to ozone formation.
Surface Coating Operations (Chapter 5 Article 13)
PCAQCD has previously regulated spray coating operation facilities operating within the Pinal County portion of the Phoenix-Mesa ozone nonattainment area under Chapter 5 Article 13 (§5-13-100 of the Pinal County Code of Regulations). The proposed update to Article 13 would expand the applicability to account for the newly redesignated areas of PCAQCD jurisdiction. In the proposed rule change notice, it is noted two spray coating facilities currently operate in the new ozone nonattainment area. However, it is important to note, any potentially new spray coating business would be applicable to the revised rule as well. The revised RACT rules for surface coating operations mandate the following key provisions:
- Emission Limits: Facilities must adopt low-VOC coatings or install emissions control systems that capture and reduce VOC emissions.
- Application Methods: High-efficiency application techniques, such as High-Volume Low Pressure (HVLP) spray guns, must be employed to minimize overspray and emissions.
- Work Practices: Operators must implement best practices for handling, storing, and disposing of VOC-containing materials to prevent unnecessary releases into the atmosphere.
Gasoline Dispensing Facilities (Chapter 5 Article 20)
As noted in the proposed rulemaking, updates to Chapter 5 Article 20 (§5-20-100 of the Pinal County Code of Regulations) would affect a handful of facilities within PCAQCD jurisdiction. PCAQCD has noted that rule changes may cause minimal impacts as several of the potentially applicable facilities are in close proximity to the Phoenix metro area, with many gasoline dispensing facilities adhering to similar standards. For gasoline dispensing operations, the updated RACT requirements focus on mitigating VOC emissions during storage and refueling:
- Stage I Vapor Recovery Systems: Facilities must install and maintain vapor recovery systems to capture gasoline vapors released during fuel transfers.
- Leak Detection and Repair (LDAR): Regular inspections and maintenance of storage tanks, pipes, and dispensers are required to prevent fugitive emissions.
- Recordkeeping and Compliance Monitoring: Operators must maintain detailed logs of inspections, repairs, and emissions data to demonstrate compliance.
Additional Ozone Considerations
In additional news, it was announced in January of 2025 that the Arizona Department of Environmental Quality (ADEQ) launched a research program designed to address the rising ozone levels in the nonattainment areas of Maricopa County and Pinal County. This program is intended to investigate local atmospheric transport, precursor emission rates, and chemical transformations within the nonattainment area to better understand the underlying causes behind the large ozone concentrations in the Phoenix metro area.
As the area is faced with the current Serious ozone Nonattainment area and a potential Severe Nonattainment redesignation in 2027, ADEQ plans to address and find ways to combat ozone formation. This study may better inform policymakers on the next steps to address nonattainment. In the future, this could possibly lead to additional or modified air quality rules and regulations, such as the soon-to-be updated RACT rules of PCAQCD. While no updates to the current Maricopa County Air Quality District (MCAQD) and PCAQCD rules are imminent, results from this significant research investment may cause future changes and revisions.
Conclusion
The expansion of Pinal County’s RACT program underscores the continuing ozone nonattainment within Pinal and Maricopa County. For spray coating and gasoline dispensing operations, modified RACT rules are directly affecting compliance obligations, emission limitations, and control requirements. For other industries and sources, while these updated RACT rules may not be applicable, future local air quality rules and regulations may be changed based off the continuing ozone nonattainment in the Phoenix metro area. If you would like to discuss how the Maricopa County and Pinal County ozone nonattainment status may affect your facility, please contact Trinity’s Phoenix office or call 602.274.2900.
