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About the Air Facility System

The Air Facility System (AFS) contains compliance and enforcement data and permit data for stationary sources of air pollution regulated by EPA, state and local air pollution agencies. The environmental regulatory community uses this information to track the compliance status of point sources with various programs regulated under the Clean Air Act. See the Clean Air Act enforcement page for information on enforcement activities.

Types of Data

A Plant is a facility represented by its physical location, and defined by property boundaries. Plant-level data include plant name, address, Standard Industrial Classification (SIC),U.S. Census Bureau North American Industry Classification System Exit EPA Disclaimer and compliance status.

A Stack is where emissions are introduced into the atmosphere. Stack-level data include the height and diameter of the stack as well as the temperature, flow rate, and velocity of the gas released into the atmosphere. Stack-level data is used in emission inventory reporting.

A Point is a physical piece of equipment or a process that produces emissions. Point-level data include normal operating schedule and the percentage of annual activity occurring each season.

A Segment is a component of a point process, such as fuel combustion, that is used in the computation of emissions. Segment-level data in AFS include Source Classification Code (SCC), annual process rate, and fuel parameters. Segment-level data is used in emission inventory reporting. Emission inventory data can be found at the Technology Transfer Network Clearinghouse.

Compliance Data
Compliance data in AFS are maintained at two levels: plant and point. Plant-level compliance data track the compliance and classification status of the plant, inspections, and other compliance actions taken against the plant. Similar data also can be tracked at the point level.

Operating Permit Data
AFS also includes data for management of facility operating permits. Current capability consists of tracking the steps in the permit issuance process. State and local air agencies report to AFS when they issue a Federal operating permit (a permit issued in accordance with Title V of the Clean Air Act of 1990). The reported data consists mainly of the Title V permit number and the date the permit was issued. The Operating Permits Program provides a mechanism for gathering together in one document all of the federal, State and local requirements applicable to air pollution sources. See the Policy on Title V Permit Program Data Elements (PDF) (5 pp, 37K,About PDF) for a complete list of required Title V data in AFS.

To view a list of Major Sources currently in AFS subject to the Title V program, see Title V Sources (PDF). (415 pp, 7K,About PDF)

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Data Input and Update Procedures

Stationary source data in AFS are collected and updated by state and/or local agencies. These agencies generally have direct access to the EPA National Computer Center and AFS. There are two mechanisms for data entry to AFS: batch and online.

For the batch update process, you create a file of transactions, transmit the file to the EPA mainframe computer, and submit a batch job. AFS software validates the transactions and uses them to update the AFS database.

The online update process uses formatted screens to acquire new or modified data. The same validation is performed online as in batch updating, and immediate feedback is provided to diagnose errors in the values entered into the screens.

When all the desired changes or additions have been entered on the screens, the software updates the AFS database.

The Universal Interface (UI) is software provided and supported by the USEPA, to assist state and local agencies with transferring their facility air compliance data to the AFS. The software acts as a converter from the state or local agency's database to the AFS through the generation of transactions suitable for submission into the AFS via the batch processing comparison and update software.

See the Summary of National Minimum Data Requirements (MDR's) for the Clean Air Act Stationary Source Compliance (PDF) (5 pp, 336K,About PDF) listing of required data elements for any source entered within AFS.

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AFS Data Retrieval

Most of the facility data in AFS are available to any person or organization with legitimate access to the EPA National Computer Center. There are three ways to retrieve facility data from the AFS database: Online Browse, Fixed Format Reports, and Ad hoc reporting.

The AFS Online Browse option displays data online. You specify criteria for data selection (such as plant name and plant identification number). The AFS software retrieves and displays the data in formatted screens.

AFS Fixed Format reporting generates printed reports and/or data files. You specify criteria for data selection and sorting, and choose options that affect report format or content. The AFS software automatically submits a batch job to produce the requested report and/or data file. Many report formats are available, and selection criteria are flexible enough to meet most information needs.

If the Standard Batch Retrieval and Online Browse facilities do not satisfy their requirements, experienced users can define supplemental reports via the AFS Ad Hoc Batch Retrieval option. You specify which data fields are used to select data, and which fields are included in the report and/or output data file. To do this, however, you must have a thorough understanding of the database organization, and data field names.

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AFS History

AFS became operational in April, 1990. AFS replaced the National Emissions Data System (NEDS), the Hazardous and Trace Emissions System (HATREMS), and the Emissions Inventory System (EIS) for emission point source data reporting. The Compliance Data System (CDS), previously used by EPA and the states for compliance and emission point source data reporting, and the Continuous Emissions Monitoring Subset (CEMS), used for the maintenance of point continuous emission monitoring data, were also replaced by AFS. During September 2000, AFS was replaced by the National Emissions Trends (NET) database as the official repository of emissions data.

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AFS Contacts

For technical information about AFS, call the AFS User Support Help line at (800) 367-1044 or see the AFS Contacts page.

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