MEMORANDUM

TO: Docket No. EPA

- HQ

- OAR

- 2012

- 0918

Air Quality Designations for the 2012 Fine Particulate (PM 2.5 ) Standards

FROM: Beth W. Palma

Air Quality Policy Division, OAQPS

SUBJECT: Florida Deferred Area Air Quality Designations for the 2012 PM 2.5 National

Ambient Air Quality Standards (SAN 5706)

This memorandum provides the rationale for the U.S. Environmental Protection Agency’s use of the additional time available to it under section 107(d)(1)(B) of the Clean Air Act (CAA) to

obtain additi onal information and further evaluate air quality monitoring data before promulgating initial area designations for the 2012 primary annual fine particle National Ambient Air Quality Standard (2012 annual PM 2.5 NAAQS) 1 in Florida.

In accordance with secti on 107(d) of the CAA, the EPA must promulgate designations for all areas of the country. In particular, the EPA must identify those areas that are violating a NAAQS or contributing to a violation of the NAAQS in a nearby area. The EPA designates these area s as “nonattainment” areas. Additionally, through the designation process, the EPA identifies areas that are meeting the NAAQS and those areas without sufficient data for the Agency to make a determination. The EPA uses a designation category of “unclassif iable/attainment” for areas where air quality monitoring data indicate attainment of the NAAQS and for areas that do not have monitors but for which the EPA has reason to believe are likely to be in attainment and are not contributing to nearby violations. The EPA reserves the category of “unclassifiable” for areas where the EPA cannot determine based on available information whether the area is meeting or not meeting the NAAQS or where the EPA has not determined whether the area contributes to a nearby vio lation.

As described in more detail in the memorandum, “ Data Quality Issues in Florida Affecting Air Quality Designations for the 2012 PM 2.5 National Ambient Air Quality Standards

, ” the EPA has

identified potential data completeness issues for areas acros s the state of Florida

. 2 These potential

data issues were revealed after the EPA announced its intention to designate the entire state of Florida as unclassifiable/attainment. Given these potential data completeness issues, the EPA is deferring designation s for all counties in the State of Florida until the Agency can assess whether a valid design value can be calculated for areas in the state . The EPA is basing designation decisions for most areas across the country on design values for the 2011

- 2013 time period.

Without the confidence to calculate a valid design value, the EPA cannot determine whether

1 On December 14, 2012, the EPA promulgated a revised primary annual PM 2.5 NAAQS (78 FR 3086, January 15, 2013). In that action, the EPA revised the primary annual PM 2.5 standard, strengthening it from 15.0 micrograms per cubic meter (μg/m 3 ) to 12.0 μg/m 3

.

2 Memorandum from Liz Naess, Group Leader, Air Quality Analysis Group, US EPA Office of Air Quality Planning and Standards, to EPA Docket EPA

- HQ

- OAR

- 2012

- 0918, Air Quality Designations for the 2012 PM 2.5 Standards, titled, “ Data Quality Issues in Florida Affecting Air Quality Designations for the 2012 PM2.5 National Ambient Air Quality Standards .”2

these areas are meeting or are not meeting the NAAQS. Accordingly, the EPA is deferring designation s and using the additional time available to it as provided under section 107(d)(1)(B)

of the CAA to asses s these data and promulgate a designation for the identified areas.

The EPA will work with Florida to finalize the designations for these counties as soon as complete certified data are available, which the EPA anticipates will allow for promulgation of these designations in accordance with section 107(d). When complete air quality monitoring data are available and have been certified, the EPA invites t he S tate to submit revised designation and boundary recommendations, as appropriate. If at that time the EPA believes that it is necessary to modify the State’s recommendation and to promulgate a designation different from the S tate’s recommendation, then the EPA will notify the State at least 120 days prior to promulgating the final designation and the EPA will provide the State an opportunity to comment on the potential

modification. The State will then have an opportunity to respond to the EPA’s proposed designations and boundaries. Pursuant to section 107(d), the EPA cannot promulgate the designation for these areas less than 120 days from the date of the EPA modification letter.

While the EPA is finalizing designations for most areas of the country

, des ignations for all areas

in the s tate of Florida will be promulgated at a later date in a separate final rule.

Approach

In determining the appropriate set of neighboring counties to include with the set of monitored

counties for which the EPA is deferrin g designations, the EPA conducted a hypothetical analysis assuming that the monitors with the incomplete data were violating the 2012 standard of 12.0 μg/m 3

. The EPA is proceeding under this assumption under the precautionary principle that

because it is u nclear whether there is a violation in this area due to data incompleteness, then for purposes of conducting the contribution analysis the EPA will presume that there may be such a

violation. The EPA’s contribution analysis for these hypothetical violation s focused on counties within the same Core Based Statistical Area (CBSA) as the affected monitor because these counties would be most likely to contain nearby sources that contribute to any violations. Specifically, the EPA evaluated all counties in the same C BSA as the county with the monitors in question, in order to determine whether these presumptively “nearby” counties ( beyond the
county with the incomplete monitoring data) contain emissions sources that would be relatively likely to contribute to an y hypothetical violation of the standard in the area with those monitors. Using information similar to the information used for determining nonattainment area boundaries, 3 the EPA e valuated the information available for these CBSAs, including Air Quality D ata; Emissions and E missions

- related D ata; M eteorology; and

G eography/ T opography. 4 One of the EPA’s p rimary boundary consideration s for determining whether to defer a final designation decision for these counties is whether the agency believes

3 Memorandum dated April 16, 2013

, from Gina McCarthy, Assistant Administrator, to Regional Administrators, Regions 1

- 10, titled “Initial Area Designations for t he 2012 Revised Primary Annual Fine Particle National Ambient Air Quality Standard.”

4 The EPA did not consider jurisdictional boundaries for purposes of deferred designations because jurisdictional boundaries are most helpful for nonattainment planning purposes, and this analysis concerns the preliminary dividing line between deferred and unclassifiable/attainment counties. No counties in Florida are being designated nonattainment pursuant to this analysis, although that could change in the future if for thcoming data reveal a NAAQS violation.3

the emission s in those nearby counties are highly likely to contribute to the potential violations,

and whether the meteorological data support a case that those emissions could significantly impact the affected monitor. Where available evidence indicates that emissio ns in adjacent counties could likely have the potential to contribute to monitors with data incompleteness, the EPA is deferring the designation for those counties as well as for the county with the affected monitor. At this time, the EPA is still evaluati ng the data for Florida statewide and thus does not have enough information to make a designation decision for any area in the State.