Enclosure

The EPA Response to Petition fo r Reconsideration from Jessie Medl in, President, DeSoto County Board of Supervisors on behalf of DeSoto County, Mississippi

By a letter dated July 17, 2012, De Soto County, Mississippi petitioned th e EPA to reconsider the final area designation for DeSoto County, Mississippi in the Memphis, Te nnessee-Mississippi-Arkansas (TNMS-AR) ozone nonattainment area. For the reasons discussed below, the EPA is denying the Petition. For the sake of clarity, we have organized this re sponse according to the structure of the July 17, 2012, petition.

I. “General Objections”

A. Reliance on Most recent Certified Data

Issue: The Petitioner claims that the EPA should have considered the 2011 certifi ed air quality data for Mississippi and Tennessee as it is th e best current scientific evidence of air quality. The Petitioner notes that in the Responses to Significant Comments on the State and Tribal Designation Recommendations

for the 2008 Ozone National Ambien t Air Quality Standards (NAAQS) dated April 30, 2012, the EPA stated that they were “relying on th e most recent 3 years of certified data to designate areas for the 2008 NAAQS” but then did not consider 2009-2011 data fo r Mississippi and Tennessee but instead relied on

data from 2008-2010. The Petitioner claims that 2009-2011 data “demonstrates conclusively that DeSoto County does not impact the air quality in Te nnessee as all of the Tennessee monitors have been certified to be in attainment during the 2009-2011 time period.” Further, the Petitioner claims that “despite growth in population in DeSoto Count y, the Tennessee monitors are not affected by Mississippi” which is consistent with the monitored attainment in the 2009-2011 monitoring period in Shelby County. Petition at 1.

Response: In determining the boundar ies for the Memphis nonattainment area, the EPA considered the most recent full set (i.e., consistent set of years) of certified air quality data for all three states that had counties located in the Memphis co re-based statistical area (CBSA) . The EPA relied on a consistent evaluation principle when presented with mixed years of data in an area, and c onsistently applied that principle to all multi-state areas. Specifically, the underlying principle is that the EPA cannot designate

an area as attainment if the most recent certified data from any of the monitors in the area for a specific 3-year period indicates a violati on of the NAAQS. Importantly, while evidence of one violating monitor

is sufficient to demonstrate that the area is vi olating the NAAQS for a sp ecific 3-year period, to demonstrate attainment of the NAAQS all monitors in the area must be meeting the NAAQS for the same 3-year period. Thus, an area cannot demonstr ate attainment of the NAAQS based on air quality data from different 3-year pe riods for different monitors. 1

1 We note that the EPA’s reliance on 2008-2010 data for monito rs in the Memphis area is consistent with our action in two other multi-state areas where some, but not all, of the states submitted early cer tified 2011 data. For the PhiladelphiaWilmington-Atlantic City, PA-NJ-DE-MD area, we relied on air qu ality data for 2008-2010 for monitors in all of the states where Pennsylvania submitted early certified 2011 data but Ne w Jersey, Delaware and Maryla nd did not. Similarly, for the Washington DC-MD-VA area, Virginia early certified 2011 data but the District of Columbia and Maryland did not and we based the designation of the area on air quality data from 2008-2010.On page 98 of the Response to Comments, th e EPA “acknowledges that Tennessee has provided certified, quality assured air quality data for 2009-2011. Arkansas, however, has not requested early

certification of their 2009-2011 data , and, therefore... [such Arkansas data] cannot be used for designations purposes.” The EPA similarly acknowledge d that Mississippi submitted early certified data for 2011. Memphis TSD at 5. The EPA went on to de scribe that “[b]ecause EPA has not received certified data from all monitors in the area, we ar e using 2008-2010 air quality da ta for our analysis of the Memphis, TN-MS-AR area.” Based on certified data from monitors in a ll three states for 2008-2010, the Shelby County monitor in Tenne ssee was violating the 2008 ozone NAAQS. While the certified data

from 2009-2011 showed that all monitors in the Tennessee and Mississippi por tions of the Memphis area were meeting the NAAQS, the EPA did not have certified monitoring data from 2009-2011 showing that the Marion monitor in Crittenden County, Arkansas was also attaining the 2008 ozone NAAQS. (We further note that preliminary 2011 data indicated that the Marion monitor was likely violating the 2008 ozone NAAQS.) In the absence of certified data from the most recent 3 years showing that the area as a whole is attaining the standard, the EPA coul d not rely on certified data from only a portion of the area to demons trate the Memphis area as attain ment. Similarly, the EPA could not rely on data from 2009-2011 for Arkansas for purpos es of the designation because the 2011 data for

monitors in Arkansas were not certif ied in sufficient time for consider ation in the desi gnation process.

For the same reason, it was not appropriate for th e EPA to have relied upon the 2009 –2011 data from Tennessee when evaluating whether all or a portion of DeSoto County was contributing to a violation of the NAAQS in the Memphis CBSA. While not expre ssly stated, it appears th at the Petitioner is suggesting two arguments. First, if the EPA had relied on data from 2009-2011 from Tennessee and Mississippi and 2008-2010 data from Ar kansas, then the area as a whol e would have been designated attainment and no contribution analysis would be need ed. Alternatively, they may be suggesting that if the EPA had relied on air quality data for 2009-2011 for the entire area, then the violating monitor

would have been the Marion monitor in Crittenden County, Arkansas and not the Frayser monitor in Shelby County, Tennessee and the cont ribution analysis would have sh own that no portion of DeSoto County is contributi ng to the violation at the Crittenden C ounty monitor. For the reasons provided above, it was not appropriate for the EPA to have ev aluated mismatched data for the three states to

determine that the entire area was in attainment, or to have altern atively evaluated data from 2009-2011

for all three states in a contribu tion analysis. In addition it was not appropriate for the EPA to have

evaluated 2009-2011 data for all three states because Arkansas did not certify their 2009-2011 data in

sufficient time for the EPA to consider it prior to the final designations.

B. Credit for Voluntary Measures

Issue: The Petitioner claims th at in a 2007 meeting with the EPA Region 4, the EPA stressed the importance of local voluntary measures and that the “EPA said that... [such] information would be used for boundary determinations.” The Petitioner claims that despite these representations the “EPA failed to recognize the significance of the reduced emissions or to give DeSoto County any consideration

thereof.” The Petitioner also claims that the EPA’s approach in ma king its boundary determinations is only specified in the Clean Air Act (CAA or Act) fo r serious areas. Based on th is, the Petitioner claims that the EPA should designate DeSoto County as attain ment or attainment/uncla ssifiable. Petition at 2.

Response: This issue could have been raised du ring the comment period and was not raised by the Petitioner, and thus is not an appr opriate basis for reconsideration. Ho wever, the EPA notes that similar issues were raised by the State of Mississippi during the designation proc ess. In response to the specific issue raised here by Petitioner, the ozone area boundaries for the 2008 ozone standard were determined by the EPA Administrator duri ng the designation pro cess based on state’s 2009 recommendations,subsequent updated state recomm endations, communication during th e 120 day consultation period, public comment, and the EPA’s five factor analysis , which included an evaluation of emissions from DeSoto County, Mississippi. During the designation process, the EPA did consider the voluntary measures put in place in Desoto County. The Petitione r is correct that for pur poses of area designations required immediately following pr omulgation of the 1990 CAA Amendments, the Act in section 107(d)(4) specifies that the nonattainm ent boundary for an area classified se rious, severe or extreme is to include the entire metropolitan statis tical area or consolidated metropolit an statistical area, by default. However, the EPA explained in its designations guidance for both the 1997 ozone NAAQS and the 2008 ozone NAAQS why it believes that to comply with th e CAA it is appropriate to evaluate information

relevant to the entire CBSA to determine an appropriate boundary for a nonattainment area. See “Boundary Guidance on Air Quality Designations for the 8-hour National Ambient Air Quality Standards (NAAQS or Standard),” memorandum from John S. Seitz, to Air Division Di rectors, March 28, 2000, pp. 3-4; “Area Designation s for the 2008 Revised Ozone National Ambient Air Quality Standards,” memorandum from Robert J. Meyers, to Regional Administrators, Regions I-X, December 4, 2008, p. 3. As noted in the 2008 memorandum, the EP A believes that using the CBSA or combined statistical area (CSA) boundaries as the starting point for asse ssing appropriate boundaries is a reasonable means for evaluating what “nearby” areas contribute to a vi olation of the NAAQS. 2 In the 2000 Seitz memorandum, the EPA explained that it is reasonable to cons ider a broad area because of the “pervasive nature of ground level ozone and its precu rsors.” Accordingly, even though there is no CAAprescribed default boundary for areas designated nonattainment for the 2008 ozone NAAQS, the EPA

evaluated information relevant to DeSoto County’s contribution to mon itored violations in the Memphis CBSA, and concluded that a portio n of DeSoto County is appropria tely designated nonattainment.

C. Consistency of Designation with 2004 Designation

Issue: The Petitioner claims that there were two flaws in the EPA’s response to Mississippi’s recommendation that DeSoto County not be include d in the Memphis CBSA because it had not been designated as part of the Memphis area for purpose s of the 1997 ozone NAAQS. First, Petitioner notes that the EPA responded by saying that it must consider the most recent information available but then failed to do so by not considering th e new air quality monitoring data from Mississippi and Tennessee. Petition at 2. Second, the Petitioner takes issue with the EPA’s statem ent that there has been growth throughout the entire Memphis area, countering that despite the populatio n growth and increase in VMT (vehicle miles travelled), “the numbers” for DeSoto County have gone down from those relied on for purposes of the 2004 designations for the 1997 ozone NAAQ S. Petition at 2. The Petitioner claims that “DeSoto County should be able to rely upon past precedent to determine what actions the EPA will

take”. Petition at 3.

Response: This issue could have been raised during the designation process a nd was not; thus it is not appropriate for reconsideration. With respect to th e Petitioner’s first genera l statement regarding the appropriate data set, the EPA addr essed the issue above in response to issue I.A. The EPA further notes that as part of our five factor analysis for the counties in th e Memphis CBSA we considered a wide variety of data that was new since areas we re designated for the 1997 ozone NAAQS in 2004. With respect to the Petiti oner’s second general statement, the EPA firs t notes that is uncl ear which “numbers”

2 In the “Boundary Guidance on Air Quality Designations for the 8-hour National Ambient Air Quality Standards (NAAQS or Standard),” memorandum from John S. Seitz, to Air Divi sion Directors, March 28, 2000, EPA used the metropolitan statistical area (MSA) or conso lidated MSA (C/MSA) as a starting point for evaluating boundary-related information and in the “Area Designations for the 2008 Revised Ozone National Am bient Air Quality Standards,” memorandum from Robert J. Meyers, to Regional Administrators, Region s I-X, December 4, 2008, EPA used the CBSA or CSA as a analytical starting point.the Petitioner is referring to, and thus is unable to re spond specifically to this point. As a general matter, however, with respect to the EPA’s evaluation of growth, the Agency “evaluated the commuting patterns of residents, as well as the total VMT fo r each county in the Memphis, TN-MS-AR CBSA. In combination with the population/popul ation density data and the location of main transportation arteries ( see above), this information [was used] to identify the probable location of non-point source emissions. A county with high VMT is generally an integral pa rt of an urban area and indicates the presence of motor vehicle emissions that may contribute to ozone formation that contributes to nonattainment in the area. Rapid population or VMT growth in a coun ty on the urban perimete r signifies increasing integration with the core urban ar ea, and indicates that the associat ed area source and mobile source emissions may be appropriate to include in the nonattainment area.” Mem phis TN-MS-AR TSD at 10. These assessments are relevant to assessing the loca tion of potentially contributing emissions sources for purposes of establishing appropriate boundaries.

DeSoto County has, in fact, experienced grow th in population and VMT since the time of the designations for the 1997 NAAQS in 2004. 3 It is also true that reporte d ozone precursor emissions in DeSoto County have decreased overall from emissi ons considered in the 2 004 designations for the 1997 ozone NAAQS, and we also note that reported ozone precursor emissions for Shelby and Crittenden Counties have also declined. Importantly, the oz one standard being eval uated for the 2008 NAAQS designation is also lower (0.075 pa rts per million (ppm) vs. 0.08 ppm) . Based on all of the latest emissions-related information, and other relevant information available to us in the five factor analysis, the EPA evaluated DeSoto County’s contribution to monitored violations in the Memphis CBSA, and concluded that a portion of DeSoto County is appr opriately designated nona ttainment for the more protective 0.075 ppm 2008 ozone NAAQS.

II. Specific factor Analysis

Factor 1 - Air Quality Data

Issue: The Petitioner claims that, while the EPA cited the Arkansas-Tenness ee-Mississippi Ozone Study (ATMOS), “EPA failed to acknowledge that DeSoto County has never had the highest ozone design value in the Memphis area ...[and th at]the ATMOS study also showed that DeSoto County had less than a 1 ppb [parts per billion] contribution to the ozone levels in the Memphis ar ea.” The Petitioner claims

that such contribution does not constitute “sufficien t contribution, even when combined with the other nine factors, to warrant a designation of nonattain ment” for DeSoto County. In addition, the Petitioner claims that the EPA improperly re lied on only the parts of the ATMO S that supported the nonattainment designation and failed to rely on the parts of the study that suppor ted Mississippi’s attainment

recommendation. Petition at 3 - 4.

Response: This issue could have been raised during the designation process a nd was not; thus it is not appropriate for reconsideration. Whet her DeSoto has ever had the high est design value in the area was

not relevant to the EPA’s evaluati on or ultimate decision. We include d a portion of DeSoto County as part of the designated area because it contributes to a violation of the NAAQS in a nearby area, not because of a monitored violation in DeSoto County. We also note that this issue could have been raised during the comment period on the designations and was not raised by the petitione r or any other party; thus it is not an appropriate basis for reconsideration.

3 The 2000 US Census data was used for the 2004 designation. The 2000 population was 107,199. The 2010 Census data was used for the 2012 designation. The 2010 population was 161,252.In the Petitioner’s claim that th e EPA ignored portions of the ATMOS study that support excluding DeSoto from the nonattainment area, the Petitioner does not point to anythi ng specific other than asserting that the study shows “that DeSoto County ha d less than a 1 ppb [parts per billion] contribution to the ozone levels in the Memphis area.” The EPA does not believe that other aspects of the ATMOS study referred to by the Petitioner contradict the fi nding that DeSoto County contributes to ambient air quality in the Memphis TN-MS-AR area. The EPA re lied on the ATMOS for the proposition that, due to meteorological conditions, the monitor site with the maximum design value for the area varies from year to year and it is important to consider the monito ring sites as a group, as well as individually, in making attainment designation determinations because the EPA determined that the meteorological regime

described in ATMOS remains relevant for the Area. TSD at 6. Other aspects of ATMOS, particularly

those related to the emissions data used in the stu dy, are no longer relevant due to the age of the data.

Instead the EPA relied on the more recent 2008 Nationa l Emissions Inventory (NEI) emissions data and

2010 Census Data as described in the TSD. Finall y, we note that the releva nt portion of the ATMOS study was only one piece of information that the EPA c onsidered as part of its five-factor analysis and standing alone this study does not definitively addre ss whether all or a portion of DeSoto County should be included as part of th e designated nonattainment area.

Factor 2 – Emissions and Emissions Related Data

A. Emissions Data (location of sources a nd contribution to ozone concentrations)

Issue: The Petitioner claims that, in the EPA’s fi nal TSD, the EPA did not specifically address or

comment on emission sources and their contributi on outlined in MDEQ’s TSD. Petition at 5 - 6.

Response: The EPA did consider the emission source information outlined in the MDEQ TSD in making its decision regarding the appropria te boundaries for the Memphis Area. As the EPA stated on page 97 of the Response to Comments, “EPA appreciates th e updated technical inform ation that Mississippi provided and has updated our technical support document accordingly. However, the technical evaluation of DeSoto County shows contributio n to the air quality in the Memphis area.”

B. Population Density and Degree of Urbanization

Issue: The Petitioner claims that the EPA should have used raw numbers to represent growth in DeSoto County instead of growth rate percentages because su ch percentages are “not reasonable measures of sufficient contribution.” To illustrate its point, th e Petitioner claims that while DeSoto County only experienced a population increase of 53,000 pe ople between 2000 and 2010, given the County’s “relatively low” starting population, this growth equates to a 48 percen t growth rate for the County. The Petitioner claims that presenting the information as a growth rate and not in the form of raw numbers is

unreasonable. Petition at 6.

Response: This issue could have been raised during the designation process a nd was not; thus it is not appropriate for reconsideration. As indicated in Table 5 on p. 9 of th e TSD, the EPA recognized both the absolute change in population as well as the perc entage change in population for the counties in the

CBSA.

Issue: The Petitioner claims that the EPA provide d no documentation or reference in support of its statement that rapid growth signifi es increasing integration with th e core urban area. Further, the Petitioner claims that “if the popul ation growth in DeSoto County we re a contributing factor, then itwould be evidenced by increased oz one readings by the DeSoto County monitor, which obviously hasn’t

occurred.” Petition at 6.

Response: This issue could have been raised du ring the comment period and was not raised by the Petitioner, and thus is not an appr opriate basis for reconsideration. Als o, the EPA does not believe that it

is accurate to conclude that if population growth within the county “w ere a contributing factor, then it would be evidenced by increase ozon e readings by the DeSoto County monitor.” Ambien t ozone levels are influenced by a wide array of factors, which is why the EPA performs an extensive five-factor analysis to determine contribution. For example, emissions of volatile organic compounds (VOC) and nitrogen oxides (NOx) do not necessarily form ozone close to the source of emissions but can be transported short or long distances before forming ozone. Moreover, whether ozone levels at a monitor are affected by emissions from a specific area or source is influenced by wind patterns.

C. Traffic and Commuting Patterns

Issue: The Petitioner reiterates cl aims expressed in Factor 2 A a nd B above. Further, the Petitioner claims that the 2008 NEI, on which the EPA relied, “i ncorrectly lists DeSoto County as having higher heavy duty diesel truck emissions than Crittenden County.” Petition at 8 – 9.

Response: See responses to Factor 2.A. and B. above . With respect to the NE I data referenced by the Petitioner, this issue could have b een raised during the comment period and was not, and thus is not an appropriate basis for reconsideration. The EPA notes th at this information is entered into the NEI by the

states. This information was used because it was the best available data availa ble during the designation process.. Regarding the Petitioner’s heavy duty diesel truck emissions cl aim, as noted in the TSD, the EPA considered the Mississippi submittal that included heavy duty diesel traffic maps and accompanying traffic data provided by MDEQ during the 120 day consultation period and determined that DeSoto County was contributing to the violating monitor in Tennessee for the reasons described in the TSD. The EPA was not provided with any revise d NEI data during the de signation process and the Petitioner has not provided any information to demons trate that it was not po ssible to provide such information during the 1 20-day consultation period.

D. Growth Rates and Patterns

Issue: The Petitioner reiterat es claims expressed in Fact or 2.B. above. Petition at 9.

Response: See response to Factor 2.B. above.

E. Level of Control of Emission Sources

Issue: The Petitioner claims that the EPA did not addr ess the level of control of emission sources portion

of the Emissions and Emissions Related Data Factor in the EPA TSD. The Petitioner claims that while there are only a few major sources to control, thos e sources are well controlled through their permits and cites specific examples where controls meet or exceed state or federal requirements. The Petitioner also claims that mobile and area sources are the largest ca tegory of emissions in the area and that MDEQ and local governments have already put measures in place to reduce those em issions. In addition, the Petitioner claims that a “marginal non attainment designation will not require further controls from mobile or area sources in DeSoto County, nor will loca l controls be necessary to reduce emission in the area.” Further, the Petitioner adds that “mobile sour ce emission will be drastically reduced over the next several years due to national emi ssion control standards effecting mobile sources.” Petition at 10.Response: This issue could have been raised du ring the comment period and was not raised by the Petitioner, and thus is not an appropriate basis fo r reconsideration. Additionally, the EPA notes that the Petitioner does not identify any specific information that the EPA failed to consider. The emissions data

included in the TSD which was the most recent data available to the EPA at the time of designations, reflect emission control measures and technolog ies in place through 2008. TSD at 6-8. The EPA also considered MDEQ’s submittals which described the vol untary control measures not captured by the NEI

data. TSD at 5.

With respect to the Petitioner’s comments regardi ng additional emissions c ontrol requirements for marginal nonattainment areas, the EPA notes that future control requirements ar e not a consideration in the designations process. The focus of designating nonatta inment areas, as prescribed in the CAA, is to

determine areas that are violati ng the NAAQS, and nearby areas that contribute to the area that is violating the NAAQS.

Factor 3 – Meteorology

Issue: The Petitioner claims that the “EPA unsoundly a pplied its analysis of mete orology in its use of the

HYSPLIT model and its use of wind roses as indicators of atmospheri c transport.” The Petitioner lists

four factors which it claims make a “back trajectory analysis usi ng HYSPLIT... patently unreliable in determining if transport was occu rring on most ozone exceedance da ys.” In addition, the Petitioner

claims that the EPA failed to factor in the wind di rection variability indicate d by the surface wind roses for the Memphis Area in its analys is. Finally, the Petitioner claims that the EPA failed to acknowledge that the DeSoto County monitor has never had the highest design value for the Area.

Response: This issue could have been raised during the comment process by the Petitioner. However, this issue was raised by the State during the design ation process and was addressed by the EPA in the final TSD for the Memphis area. Thus is not appropria te for reconsideration. With regard to the EPA’s use of NOAA’s HYSPLIT trajectory model, the EPA believes the back-trajectory analysis is reliable. The EPA acknowledges that HYSPLIT tr ajectory model analys es (along with any atmospheric transport model) have some level of uncertainty. Howe ver, the HYSPLIT trajectory model uses sound atmospheric transport science and archived meteor ology data from the National Weather Service to provide useful information to evaluate pollutant tran sport patterns. The locations identified by individual back trajectories may be somewhat uncertain, but wh en a relatively larger numb er of trajectories pass over a given area (i.e., portions of DeSoto County), th ere is increased confiden ce in the results of the analysis ( see the discussion of the EPA’s HYSPLIT analyses in the Meteorology Factor section of the EPA’s TSD). The EPA believes HYSPLIT trajectories are a useful tool for evalua ting pollutant transport and has used them in analyses for a number of ozone nonattainment areas during the designations process for the 2008 NAAQS. As stated in the EP A’s TSD, “HYSPLIT trajectories alone do not conclusively indicate contribution to monitored violations of the ozone NAAQS and therefore cannot be

used to determine inclusion or exclusion of an area with regard to ozone designations. Rather, HYSPLIT trajectories are useful supporting in formation that compliment other meteorological information, as well as information concerning the othe r factors, (emissions, etc.).”

With regard to the EPA’s use of wind roses, figur es 4a-4d in the EPA’s TSD were generated using

surface-level winds measured at the Memphis International Ai rport National Weather Service meteorology station which is approx imately 12 miles south of the Fr ayser monitor, between DeSoto County and the monitor ( see Figure 9 in the EPA’s TSD). The EPA determined this data to be representative of the winds in the Memphis area. The EPA acknowledges that the wind roses show variability of wind directions on da ys where exceedances of the ozone standard were measured at theFrayser monitor during the 2008-2010 timeframe. However, the wind ro ses clearly show that winds were blowing from a southerly di rection during a large percentage of time when exceedances were measured, thus providing evidence that ozone precursor emissions fr om DeSoto County can contribute

to the measured ozone concentrations.

With regard to the Petitioner’s claim that the EPA failed to acknowledge that DeSoto County has never had the highest ozone value fo r the Memphis area, please see the EPA’s response above for Section II,

Factor 1.

Issue: The Petitioner also claims that the EPA’s findi ng of the possibility, or th e suggestion that sources in DeSoto County contributed to elevated ozone locat ions is not the same as finding that the County sufficiently contributed to such oz one levels, and as such, do not pr ovide a strong basis for the EPA’s designation.

Response: As described in the TSD, the EPA conducte d a five factor analysis to evaluate whether DeSoto County contributed to violations of the NAAQS in the Memphis area. The use of the terms “possible” and “suggests contribution” referenced by th e Petitioner appear in the TSD in relation to the

EPA’s evaluation of each individual factor. The EPA evaluated each factor independently and then reached a conclusion regarding contribution after cons idering a weight of the evidence of relevant information related to all five factors. Conseque ntly, the terminology cited by the Petitioner from the analysis of individual factors does not reflect a summary assessm ent of whether DeSoto County

contributed to the violations in the CBSA. For example see the Conclusion section of the December 8, 2011, TSD, at pages 11 and 12.

Issue: The Petitioner claims that the EPA failed to c onsider the fact that the “back trajectories shown in the TSD travel over areas of Memp his prior to arriving at the Frayser monitor with much higher NOx and VOC emissions density than [do those from] Desoto County.”

Response: This issue could have been raised du ring the comment period and was not raised by the Petitioner, thus is not an appropria te basis for reconsideration. The EP A did consider the fact that the back trajectories which travel over DeSoto Count y also travel over areas of Memphis located in Tennessee (Shelby County). The EPA recognizes that emission sources in the Tennessee portion of Memphis also contribute to the measured ozone exceedances at the Frayser monitor. However, the

EPA’s assessment of the five f actors (including emissi ons, meteorology, and othe rs) presented in our TSD shows that DeSoto County ha s: the second highest emissions levels of NOx and VOCs in the Memphis TN-MS-AR CBSA; large VMT; a large popul ation increase; and winds showing transport toward the Frayser monitor. Based on this info rmation, the EPA conclude d that ozone precursor emissions from DeSoto County also contribute to the measured oz one exceedances at the Frayser

monitor.

Issue: The Petitioner claims that th e “EPA rushed to judgment, thereby failing to base its decision on the best available scientific knowledge.” As evid ence, the Petitioner quotes the EPA’s Response to Comments as stating that “[i]n those cases where timing constraints and the lack of additional information prevented a more detailed assessment, EP A believes that the default wind rose analyses, in conjunction with the remainder of the multi-factor analysis, can provide an adequate assessment of appropriate boundaries.” Petition at 11 – 12.Response: The EPA did not rush to judgment, and us ed the best available information to make final designations decisions. The same type and quality of in formation was not available for all areas that the

EPA evaluated. The EPA notes that the Petitioner’s understanding of the quote from the Response to

Comments document is taken out of context. This stat ement is referring to states, unlike Mississippi, that did not conduct back trajectory an alysis and concludes that “the default wind rose analysis in conjunction with the remainder of the multi-factor analysis can provide an adequate assessment of appropriate boundaries.” The EPA’ s meteorology factor discussion in the Memphis TSD provides a summary of the detailed technical analyses that were undertaken to assess pollutant transport, including wind roses created with Memphi s International Airport Nationa l Weather Surface data, HYSPLIT trajectory analyses and an assessm ent of previous ozone modeling st udies in the Memphis area. This

detailed information shows that th e EPA considered the best informa tion available for our analysis of the Memphis area.

Factor 4 - Geography/Topography

The Petitioner did not provide any comments asso ciated with this f actor. Petition at 12.

Factor 5 - Jurisdictional Boundaries

Issue: The Petitioner claims that state and county ba rriers “should be given great er consideration in the case of DeSoto County.” The Petitioner claims that b ecause DeSoto County is in a separate state from the counties with the violating monitor the state is unable to address the nonattainment using the provisions afforded by the CAA to ge t back into attainment. The Petitio ner then reiterates its earlier claims from Factors 2.B., 2.C., 2.E., and 3 above to support its position that DeSoto County should not

be included in the nonattainment desi gnation for Memphis. Petition at 12-13.

Response: The EPA did consider the jurisdictional factor, a nd we believe that the state boundary is not a reason to exclude DeSoto County from the nonattainmen t area. TSD at 15. With respect to points the Petitioner raised in suppor t of this issue, the CAA clearly contemplates that nonattainment areas may be comprised of counties from two or more states and that these multi-state areas can work together to

address nonattainment. See, e.g. , CAA sections 107(d)(3)(A); 107(d) (4)(A)(iv); and 182(j). The EPA also notes that the points raised by the Petitioner to support its cl aim under factor five have been previously addressed by the EPA, including in re sponses to Factors 2.B., 2.C., 2.E. and 3 above.