Spatial analysis regarding compliance by major sources of air pollutants may be done using any of these identifiers. AIRS-AFS is updated by the States on a quarterly basis if there is new information for that quarter. The records contain information on dates for compliance events such as inspections, notices of violation, administrative orders, and civil referrals. This allows temporal analysis using AIRS-AFS data. The nationally required data contained in AIRS-AFS are consistent.
Spatial inconsistencies exist in the additional data provided by States.
The level of detail varies between States as a function of State programmatic needs. Additionally, the definitions of violations may differ among States. In instances where spatial consistency is required, the analyses should be limited to the nationally required data. Some inconsistencies are also present in the code values assigned for classifying sources as major or non-major sources. Such differences are due to redefining major sources as per Title V. Finally, some States may also be more diligent than others about timely updates of the database.