What is Arizona’s State Implementation Plan (SIP)?
Arizona’s State Implementation Plan (SIP) is the cumulative record of all air pollution strategies, state statutes, state rules, and local ordinances implemented under Title I of the Clean Air Act by government agencies within Arizona. There is no one “State Implementation Plan” to refer to. Instead, there are multiple revisions to the SIP that are updated and referenced when managing Arizona’s air quality.
Since Arizona’s first SIP submittal in 1972, SIP revisions, statutes, ordinances, and rules are continually being updated by ADEQ’s Air Quality Division’s SIP Section. Once revisions to Arizona’s SIP are approved by the Environmental Protection Agency (EPA) and published in the Federal Register, the SIP becomes enforceable by federal and state government. The contents within the SIP mandate permits and compliance practices.
SIPs are used to comply with the Clean Air Act, and to improve air quality for everyone and everything. SIPs outline the approach a state is going to take to bring a geographic area—and the stakeholders who conduct business and operations in the area—into “attainment,” or meeting the national standards for criteria pollutants.
What geographic areas do SIPs apply to?
All of them! For ADEQ, the SIP Section compiles SIP revisions for all counties of Arizona, particularly those outside major cities like Phoenix and Tucson. In addition, local agencies like the Maricopa Association of Governments and the Pima Association of Governments complete SIP revisions for their respective counties and ADEQ submits them to EPA.
What does the SIP do for air pollution?
The National Ambient Air Quality Standards (NAAQS) set forth in the Clean Air Act play a key role in the development of air quality laws, regulations, and SIP revisions. The NAAQS set a maximum level for six pollutants, known as “criteria pollutants,” in the ambient air. “Ambient air” is defined as the portion of the atmosphere, external to buildings, to which the general public has access. Criteria pollutants regulated by the Clean Air Act are (in no particular order):
- Carbon Monoxide (CO)
- Nitrogen Oxides (NOX)
- Particulate Matter (PM)
- Sulfur Dioxide (SO2)
- Ozone (O3)
- Lead (Pb)
These criteria pollutants are the subject of SIP revisions when EPA updates the national standards. These standards help decrease pollution in the ambient air to protect human health and the environment. The Clean Air Act also mandates other types of plans for pollutants and sources such as:
- Clean Power Plan | Learn more
- Regional Haze Plan
- New Source Review
In addition to criteria pollutant plans under SIP, the Air Quality Implementation Planning (AQIP), also develops other plans required by the Clean Air Act (CAA). These plans cover a wide range of topics and can be spurred by special circumstances such as when EPA addressed a national issue like climate change with the promulgation of the Clean Power Plan. | Learn More >