Enclosure

EPA Response to Letter in Support of Wise County’s Petition for Reconsideration from State Representative Wayne Smith, District 128

By letter dated July, 12 2012, Wayne Smith, State Repr esentative for District 128, submitted a letter in Support of Wise County’s Petition for Reconsiderat ion for the EPA to reconsider the final area designation for Wise County in th e Dallas-Forth Worth (DFW) area. For the reasons discussed below and in the Response to Wise County’s Petition fo r Reconsideration, the EPA is denying the Wise County Petition. For the sake of clar ity, we have organized this respon se according to the structure of your July 12, 2012 letter.

I. Concern About Treatment of the Oil and Gas Industry

Issue: Your letter expresses conc ern that the EPA’s decision was a nnounced shortly after the discovery of 2010 comments made by former EP A Region 6 Administrator Al Arme ndariz, stating that the EPA’s enforcement goal was to “crucif y” the oil and gas industry.

Response: The EPA’s final designa tion decision for the DFW area was based on the EPA’s evaluation of the data and technical information, extensive and thoughtful consideration of input from TCEQ and other interested parties. The EPA’s Office of Air and Radiation works cl osely with technical staff in the EPA’s regional offices to ensure that decisions are based on the factual record and are consistent across the country. As demonstrated in the Technica l Support Document (TSD) accompanying the EPA’s intended designations issued in December, 2011 and the TSD accompanying the final designation on April 30, 2012, the EPA performed a thorough assessment of information relevant to five designationsrelated factors in determining whic h areas should be incl uded as part of the DFW nonattainment area. The final decision was made by Admi nistrator Lisa Jackson based on th e record before the EPA. We

further note that there are other Te xas counties where oil and gas produc tion and activity occur that were initially considered for inclusion into a nonattai nment area, but were ultimately not included. For example Hood County, Texas and Matagorda County, Texas were considered and proposed for inclusion in their respective areas . However, following a review of comments from Texas and from public commenters and upon further evaluation of all av ailable data relevant to their contribution to ozone violations, we determined those counties should not be included as part of a nonattainment area.

Our record details those decisions.

II. Support for Wise County Petition:

Issue: Your Letter urges the EPA to carefully cons ider the Wise County Petition for Reconsideration.

Response: We carefully considered the petition filed by Wise County and have included a copy of our Response to the Wise County Pe tition for Reconsideration.III. Emissions Data and Modeling:

Issue: Your Letter claims that th e EPA must demonstrate that emi ssion sources in the County make a meaningful contribution to the DFW nonattainment area ozone exceedances. Your Letter also claims

that the EPA’s reliance on HYSPLIT modeling only estimates hourly pos itions of wind parcels and is not capable of directly measuring th e transport of ozone from one area to another. Further, your letter claims that back trajectory analysis is of limited us e in tracking ozone contribut ion and transport, per the EPA TSD for 2004 ozone designations; “... trajectory analysis ... does not take into consideration atmospheric chemical processes, the injection of emissions, or the deposition of material along the trajectory path.”

Response: This issue was raised during the comment period; thus it is not an appropriate basis for

reconsideration. We addressed these comme nts in our record, as detailed below. See our final DFW TSD titled “Dallas-Fort Worth, Texas Final Area Desi gnations for the 2008 Ozone National Ambient Air Quality Standards” and “Responses to Comments Document (RTC) on th e State and Tribal Designation

Recommendations for the 2008 Ozone National Ambi ent Air Quality Standards (NAAQS)” in the

docket for this action. As stated in our preliminary and final TSDs and in our RTC document, the HYSPLIT model is a sophisti cated tool but it only accounts for wind direction and potential transport of airborne pollutants; it is not a photochemical dispersion model and th erefore cannot be used to estimate or project ozone formation from precursor pollutants. See RTC pages 14, 60 and TSD pages 14 -15. However, the HYSPLIT results provide other usef ul information. The HYSPLIT approach provides transport/back trajectories during high ozone events to determine if Wise County emissions of ozone precursors are located within the area of potential c ontribution. As stated in th e TSD, the emissions in Wise County are large enough that they could cont ribute to ozone exceedance levels at a downwind

monitor. The EPA’s review of the Texas Co mmission on Environmental Quality’s (TCEQ’s) photochemical source apportionment modeling (SAM) indi cated that Wise County emissions contribute

to ozone exceedance levels at a number of monito rs in the DFW area on certain days included in TCEQ’s modeling. In our Final decision, the EPA considered the SAM submitted by TCEQ during the comment period to help evaluate the ozone generation potential of emissions from Wise County, in

addition to our consideration of HYSPL IT results and Wise County emissions. 1 Together, this

information indicated that emissions from Wise County are carried to the violating monitors on days with high ozone levels.

The statement from the 2004 TSD does not contradict anything we have said in the designation process for the 2008 Ozone NAAQS. We note that HYSPLIT back trajectories were utilized in the 2004 designations in many areas and consideration of emissi ons in the back trajectory areas and their potential

to contribute to ozone levels were al so part of the technical analyses in many areas. We further note that the State of Texas helped fund a report finalized in April 2004 that was also used in the DFW ozone designations decision in 2004 that included HYSPLIT and emissions an alysis and source apportionment photochemical modeling. 2

Issue: Your Letter claims that TCEQ demonstrat ed that Wise County emissions rarely, if ever,

contribute to ozone violations in other counties. TCEQ presented evid ence that portions of the DFW

area contribute to ozone levels in Wise County, not the other way around.

1 HYSPLIT was the only model we used during our evaluation of the meteorological portion of our five-factor analysis to inform our preliminary designations. S ee our preliminary TSD for Texas, poste d to the docket in December, 2011.

2 Final Report Dallas-Ft. Worth Transport Project Prepared for Houston Advance Research Center, April 6, 2004.Response: This issue was raised during the comment period; thus it is not an appropriate basis for

reconsideration. We addressed these comments in our r ecord, as detailed below. As demonstrated in our TSDs and RTC, although Wise County is ofte n downwind from the DFW area, on occasions the meteorological regime of the area is characterized by light and variable winds in which emissions from sources in Wise County are transp orted to nearby ozone monitors. See TSD pages 14 – 15 and RTC document page 60 (“[w]ith regard to meteorology for th ese counties, we note that we not only looked at wind patterns but also the more sophisticated wind trajectory models based on days on which elevated

ozone concentrations were measured in the area; such days are more representative of meteorological and atmospheric condit ions that are conducive to the genera tion of ground-level oz one and exceedances of the ozone NAAQS in the DFW area. ”). It is on such days that th e DFW area experiences some of its highest ozone concentrations, and the monitors nearest the sources in Wise County are among the monitors recording the highest ozone readings. As de tailed in the record, these meteorological analyses, together with the other four fact ors we evaluated, informed our deci sion to designate Wise County as

nonattainment.

Issue: Your letter states that the EPA has not provided sufficient justific ation to utilize a wind analysis in this case, when it has disregarded that same wind analysis in other instances.

Response: This issue was raised during the comment period; thus it is not an appropriate basis for

reconsideration. We addressed these comments in our record, as detailed below. First, your letter does not describe what is meant by “wind analysis,” so we will assume you are referring to the HYSPLIT analysis. We further assume that by “disregarded that same wind analysis,” you mean “did not use HYSPLIT analysis in other instance s.” As we stated in our RTC on pa ges 13 and 59, “[t]he adequacy of a particular meteorological analysis cannot be determined generically, but must be determined as one part of the multi-factor process used for each indivi dual region under consideration.” In addition, as we stated in our RTC on page 59, for purposes of iden tifying potential local and regional source/receptor patterns, the HYSPLIT wind trajector y model is an excellent tool for determining the frequencies for which areas potentially cont ribute to high ozone levels and is preferred over mo re basic assessments of wind speed and direction at a give n point location (e.g., wi nd roses, or pollution roses). These basic assessments, such as wind roses, are potentially mi sleading in cases where wind speeds are light and the wind direction is variable. The light and variable meteorological regime is one of the classic meteorological types that results in high ozone in the DFW area. In this designation process and other designation processes, the EPA has indicated that HYSPLIT does not directly model ozone, but does yield potential transport of emissions from one area to another. As we said on page 14 of the TSD, “By knowing where an air mass has traveled before reach ing a monitor where an exceedance has occurred, one can consider what potential areas of emission sources could have contributed to the exceedance.”

While it is true that the EPA was unable to use HYSPLIT modeling to inform our decisions for all

areas, 3 we believe that it is a valuab le tool and should not be disr egarded where the information is available, even if the information is not available in all areas. We considered HYSPLIT results in all

3 HYSPLIT modeling was used in the analysis for 16 areas. See the TSDs for Allentown-Bethlehem-Easton, PA; Baltimore, MD; Lancaster, PA; Pittsburgh- Beaver Valley, PA; Reading, PA; Philadelphia-Wilmington -Atlantic City, PA-NJ-MD-DE (for DE, MD, PA); Washington, DC-MD-VA; Charlotte-Rock H ill, NC-SC; Knoxville, TN; Me mphis, TN-MS-AR (TN, MS portions); Chicago-Naperville, IL-IN-WI; Baton Rouge, LA; Da llas-Fort Worth, TX; Memphi s, TN-MS-AR (AR portion); Houston-Galveston-Brazoria, TX; Denver -Boulder-Greeley-Ft Collins-Loveland, CO; and San Luis Obispo (Eastern San Luis Obispo), CA.cases where we had such information and the analysis was deemed appropriate for use. 4 As indicated in the HYSPLIT and ambient monitoring data presente d in our preliminary and final TSDs, the Eagle Mountain Lake and Keller monitor sites experience el evated concentrations of ozone on days in which wind back trajectories from these monitor sites traverse Wise County.

4 We note that there was a situation wh ere a limited HYSPLIT evaluation in an area in Pennsylvania was determined to not be appropriate for use in a specific case due to unique issues.Enclosure

EPA Response to Petition for Reconsideration from Wise County, Offi ce of the County Judge

By letter dated June 15, 2012, the Office of the County Judge of Wise County, Texas petitioned the EPA

to reconsider the final area desi gnation for Wise County in the DF W area. For the reasons discussed below, the EPA is denying the Petition. For the sake of clarity, we have organized this response according to the below general headings.

I. Emissions and Emissions-Related Data

Issue: Petitioner asserts that Wi se County and the Texas Commission on Environmental Quality (TCEQ) presented the EPA with additional information (before and after the public comment period) demonstrating that the EPA’s assessment of its mu lti-factor analysis, including emissions and emissionsrelated data was in error. Further, Petitioner clai ms that the EPA’s analysis did not include certain

scientific and monitored TC EQ report revisions related to the oil and gas sector pneu matic emissions for the periodic emissions inventory. Furthermore, th e source apportionment modeling (SAM) submitted by TCEQ and relied upon by the EPA did not use the upda ted oil and gas sector pneumatic emissions and therefore most likely overestimated these emissions in the modeling.

Response: Petitioner raised the cons ideration of such additional emi ssions related data in two comment letters submitted during the public co mment period; thus these issues are not an appropriate basis for

reconsideration. We addressed these comments in our record, as detailed belo w. In October 2011 TCEQ submitted a revised 2008 emissions inventory for oil and gas sector pneumatic VOC emissions, and we

did consider the revised VOC emissions data as part of our fina l designation decision ( see Technical Support Document, herein referred to as the TSD, pages 6-7). See also page 55 of the Response to Comment (RTC) document on the State and Tribal Designation Recommendations for the 2008 Ozone National Ambient Air Quality Standards (NAAQS) in th e docket for this action where we explain that we “reviewed the updated emissions data reported by the TCEQ....” In the RTC, we further state that “even with the reduced 2009 VOC emissions data, th e emissions from Wise County still contribute to

measured violations of the 2008 ozone National Am bient Air Quality Standards (NAAQS) at monitors in neighboring counties.” [RTC page 56]. The TCEQ submitted additiona l SAM modeling data on February 29, 2012 to the EPA that did not include the October 2011 revi sed oil and gas sector pneumatic VOC emissions data. However, we did review the October 2011 revised data, before making our final designation decision, and concluded that it did not have a signif icant effect on Wise County’s

contribution.

In support of those conclusions, it is indicated in th e record that DFW is a n itrogen oxide (NOx)-limited

area and VOC reductions have not shown as much benefit as corresponding NOx reductions in past modeling conducted by TCEQ. Furthermore, we r ecognized that the VOCs that are potentially overestimated are from oil and gas operations and that these VOC emissions “are relatively nonreactive,” i.e., they are less like ly to result in ozone formation th an VOCs that are more reactive. Accordingly, we did consider the potential impact of the new reported VOC emission levels on ourinterpretation of the SAM results for Wise, Hoo d, and Matagorda Counties and concluded that the impacts would be negligible. 1

Issue: Petitioner claims that be cause of Wise County’s small populat ion and vehicle miles traveled (VMT), it is unexpected that these types of emissions would have any significant contribution to ozone

formation.

Response: Petitioner raised the issue of the use of population a nd VMT data as indicators for determining “contribution” during th e public comment period, thus it is not an appropriate basis for

reconsideration. We addressed those comments in the record, as detailed below. While we acknowledged that Wise’s population and VMT are smalle r in comparison to that of other parts of the DFW nonattainment area, 2 we explain in our record that other f actors, such as the total emissions from the area, meteorology, and proximity to violating monitors supported our determination that Wise County contributes to violations of the NAAQS in the DFW area. As stated in our TSD, the 2008 Emissions Inventory for Wise County shows that Wise County’s nitrogen oxide emissions of 11,911 tons per year (tpy) are the 6th hi ghest of the 19 county DFW Combined Statistical Area (CSA) and the County’s volatile organic compound emissions of 17,609 tpy are the fourth highest of the 19 counties.

See TSD pages 6-7, table 3. 3 The TSD demonstrates that there ar e six ozone monitors violating the standard in the two counties adjacent to Wise Co unty (TSD Figure 1, page 3) and notes that Wise County is less than 1⁄2 mile from a violating monito r with a design value of 0.085 parts per million (TSD 2008 to 2010 data, pages 5 and 23). We also evalua ted meteorological tran sport patterns during exceedances using NOAA’s HYSPLIT model. These patter ns indicate that emissions from Wise County are transported to the DFW ozone monitors viol ating the standard based on 2008-2010 data, and we conclude that the Wise County emissions are la rge enough that they can contribute to ozone exceedances on certain days. See TSD pages 14-17, 19, 20, and 23. Wise County’s population and VMT data indicated that Wise County’s relatively high to tal emissions derive more from point and area sources associated with oil and ga s production activitie s in the county.

II. Meteorological Analysis

Issue: Petitioner claims that Wise County is unlikely to contribute to high ozone days in the DFW area

because the conditions conducive to ozone formation in the DFW area occur on days that are sunny, warm, and where winds are predominantly from th e east or southeast or winds speeds are slow. Furthermore, “the DFW area produc es enough emissions” to result in violations on high ozone days without considering contri butions from Wise County.

1 Final TSD, pages 6-8; Houston Final TSD, pages 5-7; RTC pages 52-56, including “...the VOC emissions resulting from oil & gas production activities ar e relatively nonreactive in the photochemical generation of ground-level ozone and that additionally the DFW area is NOx-limited such that VOC emissions in general do not contribute as much as NOx emissions to the generation of ground-level ozone.” And “EPA has since reviewed the updated emissions data reported by the TCEQ and notes that the revised numbers do not affect the ranking of the counties for VOC emissions. EPA’s analysis indicates that even with the reduced 2009 VOC emissions data, the emissions from Wise County still contribute to measured violations of the 2008 ozone NAAQS at monitors in neighboring counties. In making our final decision, we considered the reduced emissions and the reduction in drilling activity since 2009.” The Governor’s comment letter dated February 29, 2012, pages 17-21, also referred to other TCEQ documents that further support that DFW area is a NOx limited regime and changes to VOC levels do not result in much impact in ozone levels: TCEQ 2011 DFW 1997 8-hour Ozone Attainment Demonstration SIP – “APPENDIX E: Protocol for the Eight-Hour Ozone Modeling of the Dallas-Fort Worth Area,” and “APPENDIX D: Conceptual Model For The DFW Attainment Demonstration SIP Revision For The 1997 Eight-Hour Ozone Standard.”

2 See the final DFW TSD includes an evaluation of population data and traffic data for the 19 counties in the DFW CSA (TSD, pages 9-14). The TSD included data for Wise County and the DFW CSA (TSD, tables 6, 8 and 10).Response: Petitioner raised the use of meteorological data during the public comment period and thus it is not an appropriate basis for r econsideration. We addressed this co mment in the record, as detailed below. While we agree that Wise County is downw ind of the violating monitors on some high ozone days in the DFW area, our analys is shows that it is upwind on ot her high ozone days. Therefore we believe that Wise County does cont ribute to violations of the ozone standard at nearby monitors.

As our record states, “EPA evaluated availabl e meteorological data to help determine how meteorological conditions, such as weather, transpor t patterns and stagnation conditions, would affect the fate and transport of precursor emissions cont ributing to ozone formati on.” We note that based on past research by TCEQ and the EPA, light winds with weak frontal passages and conversion zones are a common meteorological condition that often leads to high ozone in the DFW area. (Final TSD, page 14).

Our evaluation of the HYSPLIT fi gures (Final TSD pages 28-31) a nd the individual HYSPLIT modeling files indicates that light and variable winds occurr ed during some of the highe st monitored ozone days and that some of these days included the transport of emissions from Wise C ounty to the sites of the

monitored exceedances. We also note that a review of the individual tr ajectory files, available in the docket, shows that several of the days during whic h trajectories passed through Wise County were also days that made up the first to fourth highest monitore d values (which are the values used in establishing the Design Value) at the Eagle Moun tain Lake and Keller monitors du ring the periods evaluated; these individual trajectory files were included in the supporting materials for the EPA’s preliminary and final designations. The Source Apportionment Modeling (Fin al TSD pages 15-20) also indicates that for a limited number of days during the period of the mode ling analysis there were several occasions in which emissions from Wise County were transpor ted to the nearby Eagle Mountain Lake and Keller monitoring sites (and other DFW area monitors) and contributed to the ozone exceedance levels. We note that the modeling analysis incorporates all NOx and VO C emissions from Wise County.

While it is unclear precisely what portion of the Combined Statistical Area (CSA) the Petitioner is referring to when it suggests that “DFW area” produces enough emissions to result in a violation of the standard on high ozone days, we assume the Petitioner is referri ng to the portion of the DFW CSA designated nonattainment for the 199 7 ozone NAAQS. While this may be true, it is not the sole factor

we must evaluate as it does not address whether emissions from another county (such as Wise County) may also contribute to that violation. See Catawba County v. EPA , 571 F.3d 20 (D.C. Cir. 2009).

III. Opportunity to Comment

Issue: Petitioner claims that Wise County was not provided a sufficient review of the information that Wise County and TCEQ submitted. Further, the EPA di d not offer a lawful opportunity for Wise County

and others to be involved in the decision-making process or air quality analysis. Finally, the EPA has not directly shared its data and jus tification for designating Wise Count y as nonattainment, and there was no rebuttal process.

Response: This issue relates to an opportunity to comment on information submitted to EPA during the comment period and the EPA’s evalua tion of that information in the final rulemaking, including the final TSD. As a general matter, agencies are not requi red to provide an additio nal opportunity for public comment on material supporting a fi nal rule, such as responses to comments or on information supporting a response to a comment. Such an appr oach would result in an unworkable endless rulemaking process. See Catawba , 571 F.3d at 50-51 (In rejecting a claim by New York that it should have been allowed additional input into the EPA’s d ecision to rely on a different monitor for evaluating contribution for the final designation th an it did for the intended designa tion the court noted that such anongoing exchange with the States is inconsistent with the CAA and that “Congress imposed deadlines on EPA and thus clearly envisioned an end to th e designation process.”) See also International

Fabricare Institute v. EPA , 972 F.2d 384, 399 (D.C. Cir. 1992) (notice and comment is not intended to result in “interminable back-and-forth”) and Community Nutrition Institute v. Block , 749 F.2d 50, 58 (D.C. Cir. 1984) (agency is not requ ired to provide additional opportuni ty to comment on its response to comments). This is particularly true when the ma terial does not substantively change the proposed action of the agency or does not significantly change the basis for the Agency’s decision. With regard to the designation process, there is a dditional reason that an additional opportunity for public comment is not warranted. For designations, s ection 107(d) of the Clean Air Act (CAA) sets forth a detailed and specific process between the EPA and the states. This provision provides: (i) th at Governors of states

make the initial recommendations to the EPA for de signations and boundaries; and (ii) that the EPA provide the states with 120 days notice of any intended modifications to the state recommendation prior to finalizing the designation. The 120- day notification process is for the purpose of providing “such State with an opportunity to demonstrate why any proposed modification is inappropriate.” The CAA does not expressly provide a role for any other entity (including local governments) and, moreover, expressly waives the notice and public comment proce ss of the Administrative Procedure Act for initial designations for new or revised NAAQS.

Although no public comment period is required, the EP A opted to provide such a comment period for the 2012 ozone designations. On December 20, 2011 (76 FR 78872), the EPA published a notice in the Federal Register inviting public comment from interested parties other than states and tribes on the

letters sent to states with th e intended designations. Th e notice provided that any comments should be received on or before January 19, 20 12, but, in response to requests from several parties, including Wise County, the EPA extended the public comment period to February 3, 2012. ( See 77 FR 2678, January 19, 2012). In addition, i f an interested party requested to meet with the EPA, we provided such an opportunity.

We further disagree that the EPA ha s not shared its justifi cation for including Wise County as part of the designated nonattainment area. By its initial recommendation letter of March 10, 2009, the State of Texas recommended that the EPA designate the follo wing counties as nonattain ment for the DFW Area: Collin, Dallas, Denton, Ellis, Hood, Johnson, Kaufman, Park er, Rockwall and Tarrant. In a second letter of October 31, 2011, Texas revised is initial reco mmendation for the DFW area to exclude Hood County

based on an assessment of 2008-2010 air quality data. On December 9, 2011, the EPA notified Texas of its preliminary response to recommendations from Texa s indicating that it intended to modify the state's recommended area designations an d boundaries for the DFW to incl ude Hood and Wise Counties as nonattainment. The initial TSD provided an analysis to support the EPA’s intended designations. ( See “Texas Area Designations for the 2008 Ozone Nati onal Ambient Air Quality Standards,” December 11, 2011). We asked the state to submit any additional information by February 29, 2012, for the EPA to

consider before it made fi nal decisions on designations.

Based on comments received from several parties, including the State of Texas, and additional information received during the public comment process for the designations, the EPA ultimately excluded Hood County and included Wise County in the DFW nonattainment area, as detailed in the TSD accompanying the final designations rule that was published in the Federal Register on April 30, 2012, and (“Dallas-Fort Worth, Texa s Final Area Designations for the 2008 Ozone National Ambient Air Quality Standards”). 4

4 Regarding the data used to inform our decision and the jus tification for the decision, we refer the petitioner to our TSD (for air quality, emissions, and meteorological data) and RTC in the docket for this rulemaking, which provide our reasoning for the inclusion of Wise County. Our decisions concerning nonattainment designations for the DFW area are based on technicalIV. Economic Harm

Issue: Petitioner claims that a nonattainment designation would impose significant economic ramifications on citizens and businesses in Wise County.

Response: This issue could have been raised during the comment period and in fact was raised by other parties, such as the State of Texas. Thus it is not an appropriate basi s for reconsideration. As stated in the RTC, “under section 107(d) of th e CAA, the EPA is required to designate as nonattainment an area that is violating a new or revised national ambient air quality standard or that contributes to a nearby violation. . . . In determining wh ether an area should be designated nonattainment, the EPA does not consider economic impacts because that is not rele vant for determining whether an included area is violating the NAAQS or is a near by area that is contri buting to a violation as provided under CAA section 107(d).” See RTC pages 14-15. As such, the criteria fo r designations in Section 107 of the CAA do not provide for the EPA to consider economic effects. See RTC, pages 52-53. As we stated in our RTC document, we intend for the implementation rulemaking for the 2008 ozone NAAQS to address the minimum planning and emissions control obligations for areas designated nonattainment. As the EPA considers the required elements of implementati on for the 2008 ozone NAAQS, it is our goal to propose approaches that provide flexibility and opportunity fo r efficiency to the exte nt such approaches are consistent with the CAA and will not jeopardize expedi tious attainment of the public health and welfare goals of the CAA. To the extent the CAA does no t mandate specific control measures, states may consider economic concerns in development of thei r state implementation plan s to address air quality. (See RTC pages 14-15, 52-53, and 61). Finally, we note that DFW c ounties designated nonattainment, such as Dallas, Denton, Collin, Parker, Tarrant, etc ., have continued to grow despite their previous nonattainment designations ( see TSD page 10, Table 6).

facts pertaining to these specific counties, information supplied by the TCEQ, and the EPA’s independent evaluation as explained in the TSD. [RTC page 52, see , TSD pages 1-31]