County Affected:

Parts of Yuma County | View eMap >

Nonattainment Area Designation Date:

Nov. 6, 1991

Learn more about the designation of the area in the Federal Register (FR) (56 FR 56694, Page 32) | View FR >

Classification Level: 

Moderate

Pollutant of Concern:

PM₁₀ (particulate matter 10 microns or less in diameter; 1987 standards)

Summary: 

The concentration of PM₁₀ in the air in Yuma is frequently above the federal limit established in the National Ambient Air Quality Standards (NAAQS). ADEQ is developing a nonattainment State Implementation Plan (SIP) to improve the area's air quality. The Clean Air Act requires that ADEQ include an updated emissions inventory, a modeled attainment demonstration and rules requiring controls that reduce PM₁₀ emissions.

ADEQ has initiated a stakeholder process to consult with potential regulated businesses, local governments, and the public in a collaborative effort to develop the SIP. For more information, see the Public Participation section that follows.

Regulatory Background:

In 2006, the U.S. Environmental Protection Agency (EPA) determined that the Yuma PM₁₀ Nonattainment Area had met the 1987 PM₁₀ NAAQS and issued a clean data determination (CDD). This suspended certain Clean Air Act requirements related to nonattainment areas for so long as the Yuma area continued to meet the PM₁₀ NAAQS. The CDD did not, however, result in redesignation of the Yuma PM₁₀ to attainment because additional Clean Air Act still have to be met in order to be redesignated to attainment.

On May 17, 2022, EPA took final action to recall the CDD based on recent air quality monitoring data showed that the area was consistently violating the PM₁₀ standard. In that same action, EPA also determined that the SIP was substantially inadequate to meet the PM₁₀ standard in the Yuma Nonattainment Area and requested ADEQ to submit a SIP revision meeting the applicable nonattainment plan requirements.  Failure to submit would cause the Yuma Nonattainment Area to become subject to sanctions including:

• The suspension of federal highway funds, and
• Two-for-one offsets, which requires new and modified major sources to reduce 2 tons of PM₁₀ pollutants for every 1 ton of new PM₁₀ emissions within the nonattainment area.

Failure to submit an approvable SIP would also result in the imposition of a Federal Implementation Plan for the area to address outstanding nonattainment area planning requirements and reduce PM₁₀ emissions.

May 17, 2022, EPA Action | View Action >

ADEQ must work with Yuma stakeholders to develop new rules to reduce PM₁₀ emissions and bring the Yuma Nonattainment Area into compliance with NAAQS. The area is currently classified as Moderate and is at risk of being reclassified as Serious, if the area doesn’t attain the PM₁₀ NAAQS by the applicable attainment date set in EPA’s action.

Public Participation and Related Documents