Control Analyses

SIP

Control Analyses

Revised On: Mar. 2nd, 2026 - 11:06 am

Vital to State Implementation Plans (SIPs), control analyses evaluate the availability and appropriateness of certain control measures in order to lower emissions in a nonattainment area that is not meeting the National Ambient Air Quality Standards (NAAQS). Control measures, or the actions taken to limit the amount of pollution emitted from sources, are required by laws and/or rules and can necessitate changes in technological equipment or operating procedures.

In order to determine what kind of control measures are needed for a particular area, the Air Quality Improvement Planning Section in the Arizona Department of Environmental Quality’s Air Quality Division conducts an analysis of the economic and technological feasibility of controls available in the U.S. Environmental Protection Agency’s (EPA) Clearinghouse as well as those implemented in other states | View EPA's Clearinghouse >

Many types of controls are associated with the New Source Review (NSR) program, which evaluates new and existing sources of emissions that are located in nonattainment or attainment areas. Each state is responsible for implementing control technologies for these sources through statewide NSR programs. The controls fall into different categories and are applied to emitting sources on a case-by-case basis. Selected control measures are incorporated into the appropriate air quality permit. Control measures may also be evaluated and included in maintenance and nonattainment area SIPs | Learn more about NSR >

Types of controls that are included in an analysis are:

Reasonably Available Control Measures

Reasonably Available Control Measures (RACM) are available for nonattainment areas and the related emission sources. These measures are actions taken by major, minor, or fugitive sources to lower emissions down to an allowable amount as mandated by the area’s SIP. RACM is a giant menu of control measures a state can consider when compiling a SIP for an area.

Reasonably Available Control Technology

Reasonably Available Control Technology (RACT) is part of the RACM menu and is required on existing major stationary sources in nonattainment areas. RACT is the lowest emission limitation a source can meet through control technology that is both technologically and economically feasible, and is intended to help return the area to attainment and maintain healthy air quality.

Best Available Control Measures

Best Available Control Measures (BACM) are one step up from RACM and are applicable to particulate matter nonattainment areas classified as serious nonattainment. BACM is also a menu of actions taken by sources that will further limit emissions, as it involves measures more stringent than RACM.

Best Available Control Technology

Best Available Control Technology (BACT) is a pollution control requirement applied through air quality permits for new or modified major stationary sources. Unlike SIP planning controls, BACT is determined on a case-by-case basis for each individual permitted facility. The required controls depend on the type of source, the pollutant emitted, and site-specific technical and environmental considerations.

BACT is most commonly associated with the Prevention of Significant Deterioration (PSD) program, which applies to new or modified major sources located in attainment or unclassifiable areas and is intended to preserve existing good air quality.

Lowest Achievable Emission Rate

The Lowest Achievable Emissions Rate (LAER) is the lowest possible emissions threshold for a new or modified major source in a nonattainment area. LAER represents the most stringent emission limitation achievable for a given source category and pollutant. LAER does not consider economic or technological feasibility and reflects the lowest emission rate achieved in practice by similar sources or contained in any applicable implementation plan. LAER requirements are established through the Nonattainment New Source Review (NNSR) permitting process to ensure that new emissions do not interfere with progress toward meeting air quality standards.