South Coast Air Basin Redesignation Requests and Maintenance Plans for PM2.5 and PM10 NAAQS
Summary
SCH Number
2026080230
Public Agency
South Coast Air Quality Management District
Document Title
South Coast Air Basin Redesignation Requests and Maintenance Plans for PM2.5 and PM10 NAAQS
Document Type
NOE - Notice of Exemption
Received
Posted
8/7/2026
Document Description
The South Coast AQMD is required to attain the federal National Ambient Air Quality Standards (NAAQS) for particulate matter with an aerodynamic diameter less than 2.5 microns (PM2.5) and particulate matter with an aerodynamic diameter less than 10 microns (PM10) as expeditiously as possible. The Basin is currently designated as a moderate nonattainment area for the 1997 annual and 24-hour average PM2.5 NAAQS. Effective August 24, 2016, the United State Environmental Protection Agency (U.S. EPA) formally determined that the Basin is in attainment with the 1997 annual and 24-hour average PM2.5 NAAQS based on monitoring data from 2011 to 2013. Therefore, the South Coast AQMD is formally requesting the U.S. EPA to redesignate the Basin from moderate nonattainment to attainment for the 1997 annual and 24-hour average PM2.5 NAAQS. Pursuant to federal Clean Air Act (CAA) Section 107(d)(3)(E), South Coast AQMD has developed the South Coast Air Basin Redesignation Requests and Maintenance Plans for PM2.5 and PM10 National Ambient Air Quality Standards (proposed project), which include demonstrations that the Basin is expected to maintain its attainment status for the 1997 annual and 24-hour average PM2.5 NAAQS through 2039 and other required elements such as contingency provision.
Relative to the 1987 24-hour average PM10 NAAQS, the Basin was originally designated as moderate nonattainment in 1990 and later reclassified as serious nonattainment in 1993. In 2010, South Coast AQMD submitted a request to U.S. EPA seeking a redesignation of attainment along with a first maintenance plan, which were effective on July 26, 2013. The Basin has since remained in attainment with this standard, provided that potential exceptional events like wind-blown dust and wildfires are excluded. Pursuant to federal CAA Section 175A(b), South Coast AQMD is required to submit a subsequent maintenance plan to ensure continued attainment of the standard for at least a 20-year period from the redesignation date. To satisfy this requirement, South Coast AQMD developed a second maintenance plan for the 1987 PM10 NAAQS, demonstrating that the Basin is expected to continue attaining the 1987 24-hour average PM10 NAAQS through 2033. The proposed project is an administrative exercise to fulfill U.S. EPA requirements and will benefit stakeholders by having improved clarity when implementing the applicable requirements for demonstrating and maintaining attainment with the applicable NAAQS.
Contact Information
Name
Sina Taghvaee
Agency Name
South Coast AQMD
Job Title
Air Quality Specialist
Contact Types
Lead/Public Agency
Phone
Email
Name
Eric Praske
Agency Name
South Coast AQMD
Job Title
Program Supervisor
Contact Types
Lead/Public Agency
Phone
Email
Location
Counties
Los Angeles, Orange, Riverside, San Bernardino
Regions
Southern California
Other Information
The proposed project is located within the four-county South Coast Air Basin (Basin) portion of South Coast Air Quality Management District’s (South Coast AQMD) jurisdiction, which includes all of Orange County and the non-desert portions of Los Angeles, Riverside, and San Bernardino counties.
Notice of Exemption
Exempt Status
Other
Type, Section or Code
15061 (b)(3)
Reasons for Exemption
South Coast AQMD, as Lead Agency, has reviewed the proposed project (South Coast Air Basin Redesignation Requests and Maintenance Plans for PM2.5 and PM10 NAAQS) pursuant to: 1) CEQA Guidelines Section 15002(k) – General Concepts, the three-step process for deciding which document to prepare for a project subject to CEQA; and 2) CEQA Guidelines Section 15061 – Review for Exemption, procedures for determining if a project is exempt from CEQA. No adverse environmental impacts are expected because the proposed project is comprised of an administrative update to meet federal CAA requirements without proposing new requirements or new control measures that would result in additional physical modifications. Thus, it can be seen with certainty that there is no possibility that the proposed project may have a significant adverse effect on the environment. Therefore, the proposed project is exempt from CEQA pursuant to CEQA Guidelines Section 15061(b)(3) – Common Sense Exemption. The proposed project is also categorically exempt from CEQA pursuant to CEQA Guidelines Section 15308 – Actions by Regulatory Agencies for Protection of the Environment, because it is intended to further protect or enhance the environment by demonstrating how attainment with the 1987 24-hour average PM10 NAAQS and the 1997 annual and 24-hour average PM2.5 NAAQS for the Basin will be maintained. Further, there is no substantial evidence indicating that any of the exceptions set forth in CEQA Guidelines Section 15300.2 apply to the proposed project.
Exempt Status
Categorical Exemption
Type, Section or Code
15308
Reasons for Exemption
South Coast AQMD, as Lead Agency, has reviewed the proposed project (South Coast Air Basin Redesignation Requests and Maintenance Plans for PM2.5 and PM10 NAAQS) pursuant to: 1) CEQA Guidelines Section 15002(k) – General Concepts, the three-step process for deciding which document to prepare for a project subject to CEQA; and 2) CEQA Guidelines Section 15061 – Review for Exemption, procedures for determining if a project is exempt from CEQA. No adverse environmental impacts are expected because the proposed project is comprised of an administrative update to meet federal CAA requirements without proposing new requirements or new control measures that would result in additional physical modifications. Thus, it can be seen with certainty that there is no possibility that the proposed project may have a significant adverse effect on the environment. Therefore, the proposed project is exempt from CEQA pursuant to CEQA Guidelines Section 15061(b)(3) – Common Sense Exemption. The proposed project is also categorically exempt from CEQA pursuant to CEQA Guidelines Section 15308 – Actions by Regulatory Agencies for Protection of the Environment, because it is intended to further protect or enhance the environment by demonstrating how attainment with the 1987 24-hour average PM10 NAAQS and the 1997 annual and 24-hour average PM2.5 NAAQS for the Basin will be maintained. Further, there is no substantial evidence indicating that any of the exceptions set forth in CEQA Guidelines Section 15300.2 apply to the proposed project.
County Clerks
Los Angeles, Orange, Riverside, San Bernardino
Attachments
Notice of Exemption
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