&t/l. "B" 

FRX NO. : 52B-622-1622 Rpr . 25 2883 81 : 58PM P5 

MEMORANDUM 

SUBJECT: Attainment Determination Policy for Sulfur Dioxide Nonattainrnent Areas 

FROM: Sally L. Shaver, Director 

Air Quality Strategies and Standards Division (MD-15) 

TO: Director, Air, Pesticides and Toxics Management 

Division, Regions I and IV 

Director, Air and Waste Management Division, 

Region II 

Director, Air, Radiation and Toxics Division, 

Region Ill 

Director, Air and Radiation Division, 

Region V 

Director, Air, Pesticides and Toxics Division. 

Region VI 

Director, Air and Toxics Division, 

Regions VII, VIII, IX, and X 

Purpose 

In accordance with section lO?(d)(l)(C) of the Clean Air Act, several areas that 

did not meet the primary or secondary national ambient air quality standards (NAAQS) 

for sulfur dioxide (502) were designated as nonattainrnent areas under operation of 

law. These areas were listed in an April 22, 1991 Federal Reaister notice (56 FR 

16274). In subsequent years. additional SO2 nonattainment areas were designated in 

Federal Reuister notices dated December 21, j993 (58 FR 67334) and March 10. 1894 

(58 FR 1 11 93). 

November '1 5, 1995 marks the attainment deadline for the initial group of 

nonattainment areas. No later than six months after the attainment date, EPA must 

determine whether or not these nonattainrnent areas have achieved the $02 NhQS. 

This memorandum summarizes key issues for consideration when attainment 
FQX NO. : 528-622-1622 

determinations for SO2 nonattainment areas are to be made. 

Determininn Attainment Deadlines 

The deadlines for achieving the SO2 NAAQS depend upon whether an area fails 

to meet the primary standard, the secondary standard, or both. Section 192 of the Act 

requires attainment of the primary NMQS in nonattainment areas within five years of 

the date an area is designated (for areas designated nonattainment by operation of law, 

the attainment deadline would be November 15, 1995). Section 172(a)(2) requires the 

secondary NAAQS to be attained as expeditiously as practicable. If an area is 

nonattainment for both the primary and secondary NAAQS, the State still must achieve 

the primary standard within five years of redesignation - even if EPA has granted a 

State more than five years to attain the secondary standard. Once established, the 

deadlines for attaining the 502 NAAQS are fixed. No extensions can be granted 

beyond the initial established deadline for attaining the SO2 NAAQS. 

Under sedion 179(c)(1) of the Act, EPA has up to six months beyond the 

attainment date to determine if the area in question has attained the standard. If EPA 

determines the area has atlained the NMQS, EPA will publish a Federal Renister 

notice to this effect, and provide opportunity for public comment before a final 

determination is made- if EPA determines the NAAQS was not attained by the 

attainment date, the €PA will notify the State in writing, and publish a Federal Reqister 

notice documenting the failure to attain. These determinations will be made at the 

Regional office- level. 

Guidance for Detennininq Attainment Status 

The EPA will determine whether or not a nonattainment area has attained the 

NAAQS based on air au-n avai~ersion moddingiforthat area, 

grid a demonstration thatfie cmbd&cdenv in the SIP has been fully implemented. A 

special or additional SIP submittal from the State is not required if the State has 

previously submitted a modeled attainment demonstration. If air quality data is used in 

the attainment determination, it will be data gathered from air quality monitoring sites 

that has been entered into the Aerometric Informatian Retrieval System (AIRS) data 

base. 

The EPA will begin processing and arralyring data related to the attainment of 

the SO2 NMQS immediately after the applicable attainment date for the affected . 

areas. Current EPA policy (pursuant to 40 CFR part 58) requires air quality data to be 

submitted to the AIRS data base no later than 90 days after the end of the first calendar 

quarter following the attainment date for the area. Because EPA must make the 

attainment determination no later than six months from the attainment date, States 

should submit the required air quality data as expeditiously as practicable, but no later 

than 90 days after the end of the first calendar quarter following the attainment date for 
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Summary ' 

As stated in the beginning, this memorandum provides an ovewiew of EPA's 

policy for making attainment determinations for SO2 nonattainment areas. While 

section 107 (d)(3)(E) of the Clean Air Act lists other criteria that a State must meet 

before a nonattainment area can be redesignated to attainment, the demonstration of 

attainment is the most fundamental criteria each State is expected to meet. 

The Clean Air Act, along with the pertinent parts of the Code of Federal 

Regulations are the basis for this policy. Additional guidance may also be found in the 

SO2 Guideline Document (EPA452lR-94-008. February 1994). If your or your staff 

have any additional questions or SO2 program issues needing further discussion, 

contact Eric Crump at (919) 5414719, or Laura McKelvey at (919) 541-5497. 

cc: Joe Paisie, MD-15 

Laura McKelvey, MD-15 

Eric Crump, MD-15 

Mike Thrift, OGC (2344) 

Brian Hennessey, Region I (APO) 

Kirk Wieber, Region 11 (2AWM-APB) 

Dave Campbell, Region Ill (3AM10) 

Steve Scofield, Region IV 

Mary Onishack, Region V (AR-18J) 

Tom Diggs, Region VI (GT-AP) 

Wayne Kaiser, Region VII 

Laurie Qstrand, Region Vlll 

Wally Woo, Region IX (A-2-3) 

Kelly Huynh, Region X 
FFlX NO. : 520-622-1622 

I urge Regions to coordinate closely with OAQPS' Air Quality Standards and Strategies 

Division in determining whether SO2 redesignation requests may be subject to this poIicy and to 

ensure rhat srares' submissions adequately address this and the previous policies' criteria for 

redesignating SO2 nonactainment arws to anainment. 

cc: Lydia Wegman, AQSSD 

David Mobley, EMAD 

Joe Paisie, IPSG 

Rich Ossias, OGC 
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the area. States should identiQ any issues concerning the validity of the data or 

discrepancies related to the data during this time period. The EPA will address these 

issues on a case-by-case basis, in accordance with 40 CFR part 50. 

In any attainment determination, modeling will generally be necessary to ('I) 

develop a comprehensive evaluation of source impacts in a given area, and (2) to 

determine areas of expected high SO2 concentrations based on current conditions. As 

a general rule, areas designated nonattainment based on modeling will not be 

redesignated to attainment unless dispersion modeling indicates attainment has been 

achieved. Regional offices should consult with the Office of Air Quality Planning and 

Standards for guidance on the need for modeling in particular circumstances. 

Section 179(c)(2) of the Act states that EPA may at any time revise or 

supplement the attainment determination if more complete information or analysis 

concerning the area's air quality as of the attainment date is obtained. The EPA 

interprets this to include cases where there are discrepancies concerning the validity of 

the data, or discrepancies revealed subsequent to an attainment determination, 

Even if EPA determines that an area may be meeting the SO2 NAAQS for-a 

given period of time, this does not relieve the State of its responsibility to fulfill the 

administrative requirements listed in section 107(d)(3)(A) of the act. Even if EPA 

determines that an area has attained the NAAQS, the area will remain nonattainment 

until (I) the State has requested redesignation, and (2) EPA approves the State's 

request. 

Consequences for Failure to Attain 

If an area fails to attain the NAAQS by the attainment date, EPA will inform the 

State by letter, and publish a notice in the Federal ReaisMr. The €PA would then 

expect the State to implement contingency measures in the SIP in accordance with 

section 172(c)(9) of the Act. The EPA generally expects that aU actions needed to 

implement these measures will occur within the time frame stated in the approved SIP. 

Furthermore, Section 179(d) requires the State to submit a SJP revision within 

one year after the notice of failure to attain the NAAQS is published in the Federal 

~eoister. The revised SIP must meet all the requirements of sections 7 10 and 172, and 

also include "additional measures as the Administrator may reasonably prescribe. 

including all measures that mn be feasibly implemented in the area in light of 

technological achievability, costs, and any non-air quality and other air quality related 

health and environmental impacts." One additional measure that could be required is to 

incorporate the contingency plan elements developed for the current SIP into the 

control strategy sf the revised SIP. A new contingency plan would then have to be 

submitted with the SIP revision. The attainment date applicable to the revised SIP 

would be five years from the date of the notice of the failure to attain.