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Air Quality Planning for Transportation Officials

SIP Deadlines and Attainment Dates

SIPs are required to be adopted by the State and submitted to EPA as legally enforceable plans. The CAA established the following attainment dates for ozone, carbon monoxide, and PM-10 nonattainment areas:

Ozone Nonattainment Areas
Classification Attainment Date
Marginal November 15, 1993
Moderate November 15, 1996
Serious November 15, 1999
Severe November 15, 2005 or 2007
Extreme November 15, 2010


Carbon Monoxide Nonattainment Areas
Classification Attainment Date
Moderate December 31, 1995
Serious December 31, 2000


PM10 Nonattainment Areas
Classification Attainment Date
Moderate December 31, 1994 or no later than the 6th year after designation
Serious December 31, 2001 or no later than the 10th year after designation

In practice however, actual submittals and approvals of SIPs do not always precisely follow the specific timetables established in the CAA. Therefore, there are some nonattainment areas, which still carry classifications that are well beyond their statutory attainment date, even though those areas may not be monitoring any violations of the standards. These timetables can be missed for a variety of reasons, such as:

These types of SIP delays may result in difficulties and complications for transportation conformity. Therefore, State and local transportation agencies should work with and encourage State and local air quality agencies to keep SIPs current, up-to-date, and on schedule.

Updated: 8/4/2015
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