Ten

- year Update of Limited Maintenance Plan for PM 10 ; State of Arizona; Payson

Technical Support Document
January 2, 2014

U.S. EPA Region 91

Background
On August 9, 2001, EPA issued guidance on streamlined maintenance plan provisions for certain

mo derate PM 10 nonattainment areas seeking redesignation to attainment (Memorandum from Lydia Wegman, Director, Office of Air Quality Planning and Standards, to Directors of EPA Regional Air Programs entitled "Limited Maintenance Plan Option for Moderate PM 10 Nonattainment Areas" (“LMP Policy”)). This policy allows maintenance plans for areas having a low risk of future exceedances of the PM 10 standard to forego air quality modeling, future year emission inventories, and some of the standard analyses used to d etermine transportation conformity with the SIP.
In order to qualify for the LMP option, the area should be maintainin g the NAAQS, and the average PM 10 design value for the area, based upon the most recent five years of air quality data at all monitors in the area, should be at or below 40 ug/m 3 for the annual and 98 ug/m 3 for the 24 hour PM 10 NAAQS with no violations at any monitor in the nonattainment area. (See section IV of the LMP Policy.) The 40 and 98 ug/m 3 limits are margin of safety (M OS) limits f or the relevant PM 10 standard for a given area. 1 In addition, the area should expect only limited gro wth in on

- road motor vehicle PM 10 emissions (including fugitive dust) and should have passed a motor vehicle regional emissions analysis test.

The LMP Pol icy also states that once the LMP option is in effect, the state must verify in each subsequent year that it still qualifies for the LMP option by recalculating the area’s average design value annually and determining that the LMP criteria are met for that year. If they are not met, the state should act to reduce emissions enough to requalify for the LMP option, for example, by using a contingency measure or other SIP

- approved measure. If the attempt fails, or succeeds but there is an additional failure in the future, the LMP is no longer in effect and a full maintenance plan would need to be developed. 2
The Payson PM 10 maintenance area originally qualified for the LMP o ption in 2002. In order to continue to qualify, the State must demonstrate that Payson me t the require ments of the LMP Policy for the ten

- year period after it qualifies for the LMP, and will continue to meet the criteria in the next ten yea rs.

Evaluation
Based on our evaluation of the 2011 Payson LMP update , annual reports, and supporting doc umentation, and for reasons stated in the Direct Final Rule Notice and in this technical support document (TSD), we find that Payson, AZ continues to meet the requirements of the LMP Policy , and is expected to meet the LMP requirements in the next ten year s

. EPA’s F ederal R egister notice for this submission contains the analysis supporting approval of the ten

- year

1 On October 17, 2006 EPA revoked the annual PM 10 NAAQS (71 FR 6144). Therefore, the re quirement for the average annual design value for the margin of safety is no longer applicable. 2 LMP Policy, 2001, p 3

.2

upd ate of the LMP Plans

. The following analysis supplements the information in the F ederal R egister notice for this action. None of the informati on or recommendations in this TSD a ffect our decision to approve the Payson LMP update.
1) Data Completeness
The data recovery standard of 75% , which is required by 40 CFR 50 Appendix K (2.3)(a), was met every quarter during the LMP ten

- year update period w ith the exception the 1 st quarter of 2005, where the data were 47% complete (7 of 15 samples )

. 3 Six samples were not used due to a lab weighing problem . One was excluded due to under

- s ampling, and another due to over

sampling

. 4 EPA guidance allows for dat a substitution for missing samples when the data are less than 75% complete. 5 In this case, EPA is using its discretion to allow data substitution for the following reasons: 1) EPA takes into consideration that the data recovery was 75% or more in
every other quarter during the LMP ten

- year update period ; 2) Payson met the LMP Design Value or Critical Design Value requirements in every quarter of the ten

- year update period ; 3) There appear to be no distinct seasonal patterns to the data provided in the a nnual reports to indicate that the 1 st quarter would tend to have higher 24

- hour max imum sample values than other quarters in the year ; 6 and 4) M ax imum readings in the 1 st quarter have decreased over time since 2005. W e have no data or other basis to indi cate that the missing data in the 1 st quarter of 2005 negatively affected the ability of the area to maintain the LMP status, or to continue to do so in the future.
2) Calculation of five

- year design values

T o continue to qualify for the LMP
, the LMP Policy states the following: “The area should be attaining the NAAQS and the average PM 10 design value for the area, based upon the most
recent five years of air quality data at all monitors in the area, should be at or below 40 ug/m 3 for the annual and 98 ug/m 3 for the 24

- hr PM 10 NAAQS with no violations at any monitor in the nonattainment area.” (LMP Policy pp. 2

- 3). Footnote 4 on page 3 of the LMP Policy states that “The methods for calculating design values for PM 10 are presented in a document entitled the

“ PM 10 SIP Development Guideline”, EPA

- 450/2

- 86

- 001, June 1987. The State should determine the most appropriate method to use from this Guideline in consultation with the appropriate EPA Regional office staff.” Based on the most recent five years of air qua lity data, the Payson area meets these criteria.

3 Maintenance of the PM 10 NAAQS and Limited Maintenance Plan design values for the Payson PM 10 maintenance

area

– 2001

- 2005, letter fro m Stephen A. Owens, Arizona Department of Environmental Quality to W ayne Nastri, EPA Regional Administrator, Enclosure 2, June 7, 2006. 4 Email correspondence from John Englander, ADEQ to Wienke Tax, EPA, June 17, 2013

. 5 Guideline on Exceptions to Data Re quirements for Determining Attainment of Particulate Matter Standards, U.S. Environmental Protection, April 1987

. 6 Email correspondence from John Englander, ADEQ to Nancy Levin, EPA, July 16, 2013

.3

We note, however, that over the ten

- year update period
, ADEQ was not consistent in how it calculated the five years of data. ADEQ used the max imum of the most recent five three

- year DV s for the annual rece rtification of LMP status for the years 2003, 2004, 2005, 2006, 2007 and 2011

. 7 For the 2008 certification, ADEQ used the maximum three

- year DV for the most recent three years, rather than the most recent five years. Because the data used to calculate each of the three

- year DVs covered the five years (2004

- 2008), they meet the LMP DV criterion

. For 2010
, ADEQ used the highest max sample

-- 66 ug/m 3

-- for the five

- year period (2004

- 2010)

. 8 ADEQ did not submit an annual report for the year 2009, however, the annual reports for 2008 and 2010 contain the data needed to confirm that the Payson area was well below the LMP limits for the five

- year criterion. EPA used data in the LMP reports to calculate the five

- year DV using each of the above methods for each of the ten years, and in all cases, Payson would have qualified as below the LMP DV criterion. While ADEQ’s interpretations did not result in a material difference in our decision, we recommend that for future use of the LMP Policy, States use a consistent me thod for calculating the five

- year DV for PM 10 24

- hour standard.

3) Residential Wood Combustion value

The e missions inventory in LMP Update Table 3.5 shows Gila residential wood combustion emissions as 53 tons per year ( tpy ) , based on 2008 NEI data

. However
, the 2008 NEI for Gila Fuel

- Comb

- Residential

- Wood is 61.6 t py . When the population ratio of 0.3 is applied to scale the number to the Payson area
, 9 the result is 18.5, which exceeds ADEQ’s estimated value by of 15.9 by 2.6 tons . The calculation would onl y slightly increase the percentage of Residential Wood Combustion relative to the other categories of sources

. 10 We point this out only as an inconsistency, and it does not affect our decision to approve the LMP.

4) Industrial sources

The LMP states that th e emission s data for 2008 from industrial sources w ere provided to ADEQ “in response to an annual survey conducted by ADEQ” (see Section 3.2.2, p. 10). In a

7 Maintenance of the PM 10 NAAQS and Limited Maintenance Plan design values for the Payson PM 10 maintenance

area

– 1999

- 2003, dated October 6, 2005, Enclosure 1 page 4; Maintenance of the PM 10 NAAQS and Limited Maintenance Plan design values for the Payson PM 10 maintenance area

– 2000

- 2004, dated October 6, 2005
, Enclosure 1 page 4; Maintenance of the PM 10 NAAQS and Limited Maintenance Plan design values for the Payson PM 10 maintenance area

– 2001

- 2005, dated June 7, 2006, Enclosure 1 page 4; Maintenance of the PM 10 NAAQS and Limited Maintenance Plan design value s for the Payson PM 10 maintenance area

– 2002

- 2006, dated June 7, 2007, Enclosure 1 page 4; Maintenance of the PM 10 NAAQS and Limited Maintenance Plan design values for the Payson PM 10 maintenance area

– 2003

- 2007, dated July 11, 2008, Enclosure 1 page 3; 2 012 Limited Maintenance Plan Annual Report for the Payson PM 10 Maintenance Area, dated September 6, 2012, Enclosure 1. 8 2011 Update of the Limited maintenance Plan for the Payson PM 10 Maintenance Area, Figure 4.1, January 23, 2012. 9 Final Update to the L imited Maintenance Plan for the Payson PM 10 Maintenance Area, December 2011, page 10. 10 The percentage would change from 4.6 to 5.4 of the total Payson emissions inventory.4

conversation with EPA on July 2, 2013, ADEQ clarified that the data was compiled by ADEQ from emiss ion reports that are required of all permitted major and minor sources in the area. 11

5) Control measures in the 2002 LMP

In a conversation with EPA on July 2, 2013 , ADEQ clarified that the LMP ten

- year updates do not rely on additional control measures to c ontinue to maintain the NAAQS for PM 10 and that the LMPs have not revised these measures. 12

6) Limited Growth
In order to continue to qualify for the LMP, the area must pass a test using a motor vehicle regional analysis methodology to determine whether inc reased growth in the area would threaten the assumption of maintenance that underlies the LMP policy. 13 To have an acceptable margin of safety (i.e. pass the test), the result must be at or below 98 ug/m 3 . Payson passed the motor vehicle test at 75.7 ug/m 3

, using a ten

- year vehicle miles travelled (VMT) projected increase of 23.8%. Th is VMT projected increase was based on Arizona Department of Transportation (ADOT) data for Gila County, where Payson is located. However, we note that since the LMP Update was submitted, ADOT ’s VMT data was revised downward, resulting in even less VMT projected growth over the next ten

- year period than ADEQ assumed in the LMP Plan Update. 14

11 Memo to File, Nancy Levin, July 2, 2013 Conference Call with John Englander, ADEQ , response to q uestion #4.
12 Ibid
., response to question #5. 13 Limited Maintenance Plan Option for Moderate PM 10 Nonattainment Areas (LMP Policy ), Lydia Wegman, EPA, Director, Air Quality Standards and Strategie s Division to EPA Regions I

- X, Attachment B: Motor Vehicle Regional Analysis Methodology, August 9, 20 01. 14 See ADOT website at http://mpd.azdot.gov/mpd/data/hpms.asp

.