Novem ber 8 , 2012

Reply to

Attn Of: OEA

- 095

MEMORANDUM

SUBJECT: Eagle River PM 10 NAAQS and LMP Determination

FROM: Chris Hall

ECU Air Data Analyst , OEA

TO: Justin Spenillo STAPU Air Planning Team, OAWT

Introduction At the request of the Air Planning Team in OAWT, I have conducted both a NAAQS

attainment determination and a Limited Maintenance Plan (LMP) review for the Eagle

River PM 10 Non

- attainment Area ( NAA )

. Based on statistical analysis I have found th e Eagle River PM 10 NAA to be meeting the attainment and design value criteria necessary

to qualify for the Limited Maintenance Plan option i

.

Background

On September 29 , 201 0

, the State ( Alaska DEC or ADEC ) submitted to EPA for approval the Eagle River PM 10 LMP and requested that EPA re

- designate the Eagle

River NAA to attainment for the PM 10 NAAQS.

To qualify for the LMP option the NAA must be attaining the PM 10 NAAQS

, and in the simplistic case, the A verage Design Value ( A DV) must be below the LMP defined design value ( DV) for both the 24

- hr and annual ii PM 10 standards iii (98 μ g/m 3 and 40

μ g/m 3 respectively)

. U til izing 2003 through 2007 data from the Parkgate site

, ADEC provided in their 9/29/10 submittal that the Eagle River NAA had been attaining the

PM 10 NAAQS and that the 24

- hr A DV w as below the 24

- hr LMP defined DV limit iv

.

T he 2001 LMP memo requires that the most recent five y ears of data be used to determine LMP eligibility . Therefore the purpose of this review is to determine if the Eagle River PM 10 NAA attains the PM 10 NAAQS for 2009

- 11 and to determine if the

LMP option is an a vailable option for ADEC based on a DV analysis for years 2007 through 20 11

.Data Quality Rev iew A data quality review of the 2007

- 11 data was performed and found that both the Parkgate PM 10 sampler s me t or exceeded specified criteria in 40 CFR Part 58 for bias,

verifications checks and audits v . Based on these results the Eagle River/Parkgate PM 10 data has been deemed to be of appropriate quality for determining NAAQS attainment for years 2009

- 11 and LMP eligibility for the 2007

- 11 timeframe.

Data Completeness

T he Eagle River/Parkgate PM 10 data me t the Part 50 Appendix K minimum completeness cri teria of 75% for all quarters from 2007 through 2011; therefore no data substitution is necessary for determining compliance to the NAAQS or determining LMP eligibility.

NAAQS Attainment

Because the annual PM 10 standard was revoked effective December 18, 2006, this document discusses only attainment for the 24

- hour PM 10 standard. To show

attainment for the 24

- hour PM 10 NAAQS the 3 most recent years of data must be below

1.0 Expected number of Exceedances (EE) p er the criteria established in Appendix K to

40 CFR Part 50. As well three consecutive years of complete data is needed to make an affirmative attainment determination. A year is deemed complete if each of the four quarters has at least 75% data comple te ness.

T he Eagle River/Parkgate continuous PM 10 monitor recorded two exceedance of the 24

- hour standard on October 30 , 2009, and September 24, 2010 for the 2009

- 11

timeframe vi

. On November 2, 2012, Region 10 concurred that the October 30, 2009

exceedance was due to an exceptional event, therefore this concentration value for this day will not be included in the PM10 expected exceedance calculation. Thus if including only the September 24, 2009 exceedance t he Eagle River EE is computed to

be 0. 4 over the three most recent DV years . As this EE value is below the 1.0 limit the Eagle River NAA is not in violation of the PM 10 NAAQS for the 2009

- 11 timeframe

.

LMP Design Value Computation Results

24 Hour PM 10 NAAQS There are multiple DV determination methods provided in the EPA PM10 SIP Development Guideline , EPA

- 450/2

- 86

- 001, June 1987 . Each method has value and

drawbacks individually and as a group can provide convincing evidence that an area is

either meeting or exceeding the 24

- hr LMP defined DV

. For purposes of this analysis the Upper 10% Tail Distribution method and the Tabular Estimation methods are

utilized

.

The advantage of the Upper 10% Tail Distribution method is that this statistical approach only takes into account the high 10% concen tration values which are the most important when determining a n A DV. The advantage of the Tabular Estimation methodis that it does not require any data computations. Both method s allow for data

substitution which is necessary for incomplete data sets.

The 24

- hr and annual A DV computations provided below utilize data from the full five years rather than a running average of the three 3

- yr DV averaging periods. Using the full five years provides a larger and more robust data set for computing these two A DV

statistics

.

- Upper 10% Tail Distribution This method is a straight statistical equation derived by EPA/ OAQPS and only uses the high 10% of data values.

Equation 1 : A DV = X 90 + 3.612 (U 90 - X 90 )

Where for the Eagle River sites

X 90 = 90 th percentile value = value 117 = 34.0 μ g/m 3

U 90 = mean of the upper 10% of values = 50.5 μ g/m 3

Total Data points = 1166

Solving equation 1 with the provided values yields a 24

- hr A DV of 93 μ g/m 3

.

– Tab ular Estimation Method

The T a bular Estimation method is simply a table which tells you which data value to use

as your A DV and is dependent on the total number of data values in your data set

.

No. of Daily

Values Rank of Upper

Bound Rank of

Lower

Bound Value Used for LMP DV

≤ 347

- 1 Highest Value

348 to 695 1 2 Second Highest Value

696 to 1042 2 3 Third Highest Value

1043 to 1390 3 4 Fourth Highest Value

1391 to 1738 4 5 Fifth Highest Value

1739 to 2086 5 6 Sixth Highest Value

Utilizing the Tabular Estimation table above and b ased on a total of 1166 data points

t he 2007

- 2011 A DV value would be the 4 th highest value or 95 μ g/m 3 (see below)

.Monitor ID Arithmetic Mean (Daily) Collection Date Rank

02-020-1004-81102-1 223.0 02-Dec-2007 1

02-020-1004-81102-3 207.0 24-Sep-2010 2

02-020-1004-81102-3 136.0 31-Oct-2009 3

02-020-1004-81102-1 95.0 15-Apr-2011 4

02-020-1004-81102-3 92.0 02-Apr-2010 5

02-020-1004-81102-3 78.0 22-Apr-2009 6

Annual PM 10 NAAQS

The A DV for the annual standard is simply the arithmetic mean of all the daily values

within the data set. For the 2007

- 11 timeframe the average concentration is 17 μ g/m 3

for Eagle River . This ADV is well below the LMP defined upper limit of 40 μ g/m 3

.

Summary In summary each computational method described above show s that the 2007

- 11 PM 10 A DVs for the Eagle River NAA are well below the annual and 24

- hr LMP defined DVs

. Using the most conservative approach the 24

- hour A DV was found to be 95 ug/m3

, and

the annual A DV was found to be 17 μ g/m 3

. Based on the data quality and statistical

result s , the Eagle River NAA meets the attainment and design value criteria to qualify

for the LMP option

.

i Memorandum from Lydia Wegman, Director AQSSD, ‘LMP Option for Moderate PM10 Non

- attainment Areas’, August 9, 2001

. ii Subsequent to the issuance of the 2001 LMP O ption memo, EPA revoked the annu al PM10 standard. See 71 Fed. Reg. 61,114 (Oct. 17, 2006).

iii An area may still qualify for the LMP option if it cannot meet these basic CDV criteria by meeting the site

specific CDV. Determination of the site

- sp ecific CDVs was not necessary for this LMP analysis.

iv ADEC calculated the Eagle River EE to be 0.0 and the LMP 24

- hr ADV to be 92 μ g/m 3 but they did not include the 12/2/07 exceedance in their EE and ADV calculations. The 12/2/07 event was flagged by ADEC for EE exclusion but it was never concurred on by EPA.

v Region 10 a lso determined that the PM 10 data from the Eagle River monitors me t quality criteria through December 31, 2009 in the NAAQS attainment determination rulemaking dated October 19 , 20 10 ( 75 FR 64162 )

. vi On both of these days the manual federal reference monitor was idle due to it being a non scheduled sampling day.