PH l07.83-04_2~_~

UNITED STATES ENVIRONMENTAL. PRO'i::C'iION AGENCY

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MEMORANDUM

SUBJECT: SAetion 107 Designation Policy Summar,y

FROM: ~,4'.~~ Sheldon Meyers,-DirttfOr -- Office of Air Quality Planning and Standards (ANR-443)

TO: Director, Air and Vaste Management Division

Regions II-IV, VI-VIII, X

Director, Air Management Division

Regions r, V, IX

On February 3, 1983, the Agency' published a Federal Register notice

regarding the status of all areas designated nonattainment under Part 0

of the C1ean Air Act. This notice indicated that for a significant number of nonattainment areas States are ant1~ipated to be able to

demonstrate attainment of the primary nationa' alDfent air quality standards.

Accordingly, for those areas, States hav. been encouraged to update their

Section 107 designations'. In addition, a number of nonatta1nment areas were

identified in the February 3, 1983, notice as ·unlikely to attain standarc1s. u

The Federal Register also stated that the basic existing pol1e,y will generally be con~inued for redesignation. This memorandua sum.arizlS and clarifies

existing pol1cy for reviewing designations and provides new guidance on

processing these actions.

Policy For Reviewing 107 Designations

1. Data: In general, all available information relative to the attainment

status of the area should be reviewed. These data should include the most

recent eight (8) consecutive quarters of quality assured. representative ambient air quality dat~ plus Ividence of an impl.mented control strategy that EPA had fully approved. Supplemental information. including air

quality mod.,ing emissions data, etc., should be used to deterunne if

the monitoring data accurately characterize the worst ~as. air quality in the area. Also, the following items can be considered in special situations•

.An attainment designation can be made using only the most recent four (4)

quarters of ambient data if an acceptable state of the art modeling analysis (such as city-specific EKMA for ozone) is provided showing that the basic

SIP strategy is sound and that actual, enforceable emission reductions are

responsible for :he recent air quality improvement.

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For nonattainment designations which were originally based solely on

mOdeling. redesignation to attainment is possible even if less than four (4)

quarters of ambie~t data are available provided that a referente modeling analysis tonsidering the sourtes' legal emission l'imits shc.s attainment of

the standards. Informat~on must also be presented showing that the sources

causing the problem are in compHance with the enforceable SIP lIItasures.

. Although the current ozone standard tlllPl1es thl need for thrH y.ars of data for attainment designations, two Ylars of dati with no .xceldanclS

is an acceptable surrogate. As discussed previously. this should b.

accompanied by .vidence of an impl_nted control strate", that EPA had

fully approved.

2. ~ected Future Violations: Projections of future nolations tan

provide the basis for tontinuing nonattainment designations. This

concept is'particularly important betause of the current econoarit downturn.

InfoMmation submitted to support !·ta;nment redesignations must adequately and accurately reflect anticipate, operating rates. Areas should remain

nonattainment where such projections reveal air quality violations.

3. Model ina: In mest 502 cases, monitoring data .10ne will not be

sufficient for areas do.inated by point sources_ A .-.11 n~r of ambient

monitors usually is not representative of the air quality for th. entire

area. Dispersion modeling employing the l.gally enforc.abl. S02 SIP liarits

will generally be n.cessar,y to evaluate compreh.nsively the sources' ;~Iets

as well as to identify the areas of highest concentrations. If either the

mod.';ng or monitoring indicates that S02 air quality stlnGardS are being violated. the Irea should remain nonattlin..nt.

4. Boundar;es: Current policies on appropriate boundaries for designation of nonattainment areas by EPA remai n in effect. ; .e•• generally politi cal

boundaries such as city or county for TSP and S02. county as a minimum for rural ozone, entire urbanized area and fringe areas of ~eY,'op..nt for

urban ozone, and urban core area for CO. When States redesignate. EPA

will continue to accept reasonabl. boundaries which are supported by

appropriate data. such as specific new mOnitoring and/or modeling data or

evidence of improvement due to control strategy i~l...ntation. Monatt.1nment areas for ozone should include the significant vac sourc.s.

5. Oisoersion Techniques: Areas whith are projected to attain the TSP

or 502 standards because of the use of unauthorized dispersion techniques should continue to be designated as nonattainment.

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Policy for Processing 107 Redesianations

1. SIP Review Actions: Section 107 designations have generally been

classified as minor actions, with only a few of the more significant

ones being processed as moderate. In the future, redesignations of Tier II

nonattainment areas should be classified as major actions so that they

can receive a comprehensive review to help ensure regional consistency. Rede5ignation of Tier 1 nonattainment areas should continue ~o be handled

as minor or moderate actions, as appropriate.

2. ·Unclassifiable- Areas: Since EPA and the States have had nearly five

years to resolve discrepancies for nonattainment designations, it is now

inappropriate to redesignate any area from nonattainment to unclassifiable. There has been ample time since the first designations were made

in 1978 to thoroughly study each nonattainment area. Sufficient data

should now exist to either make a redes1gnation to attainment or to keep the nonattainment designation. .

If you have any questions, please contact Tom Helms at (FTS) 629-5525.

cc: Regiona' Administrator. Regions I-X

Chief, Air Programs Branch. Regions t-X

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