November 8, 2012

Reply to

Attn Of: OEA-095

MEMORANDUM

SUBJECT: Eagle River PM10 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 PM10 Non-attainment Area (NAA). Based on statistical analysis I have found the

Eagle River PM10 NAA to be meeting the attainment and design value criteria necessary 

to qualify for the Limited Maintenance Plan optioni

. 

Background

On September 29, 2010, the State (Alaska DEC or ADEC) submitted to EPA for 

approval the Eagle River PM10 LMP and requested that EPA re-designate the Eagle 

River NAA to attainment for the PM10 NAAQS.

To qualify for the LMP option the NAA must be attaining the PM10 NAAQS, and in the 

simplistic case, the Average Design Value (ADV) must be below the LMP defined 

design value (DV) for both the 24-hr and annualii PM10 standardsiii (98 μg/m3 and 40

μg/m3 respectively). Utilizing 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 

PM10 NAAQS and that the 24-hr ADV was below the 24-hr LMP defined DV limitiv. 

The 2001 LMP memo requires that the most recent five years of data be used to 

determine LMP eligibility. Therefore the purpose of this review is to determine if the 

Eagle River PM10 NAA attains the PM10 NAAQS for 2009-11 and to determine if the 

LMP option is an available option for ADEC based on a DV analysis for years 2007 

through 2011.
Data Quality Review

A data quality review of the 2007-11 data was performed and found that both the 

Parkgate PM10 samplers met or exceeded specified criteria in 40 CFR Part 58 for bias, 

verifications checks and auditsv. Based on these results the Eagle River/Parkgate PM10

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

The Eagle River/Parkgate PM10 data met the Part 50 Appendix K minimum 

completeness criteria 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Because the annual PM10 standard was revoked effective December 18, 2006, this 

document discusses only attainment for the 24-hour PM10 standard. To show 

attainment for the 24-hour PM10 NAAQS the 3 most recent years of data must be below 

1.0 Expected number of Exceedances (EE) per 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 completeness. 

The Eagle River/Parkgate continuous PM10 monitor recorded two exceedance of the 24-

hour standard on October 30, 2009, and September 24, 2010 for the 2009-11 

timeframevi. 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 the 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 PM10 NAAQS for the 2009-11 timeframe.

LMP Design Value Computation Results

24 Hour PM10 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% concentration values which are the most 

important when determining an ADV. The advantage of the Tabular Estimation method 
is that it does not require any data computations. Both methods allow for data 

substitution which is necessary for incomplete data sets.

The 24-hr and annual ADV 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 ADV 

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: ADV = X90 + 3.612(U90 - X90)

Where for the Eagle River sites

X90 = 90th percentile value = value 117 = 34.0 μg/m3

U90 = mean of the upper 10% of values = 50.5 μg/m3

Total Data points = 1166

Solving equation 1 with the provided values yields a 24-hr ADV of 93 μg/m3.

– Tabular Estimation Method

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

as your ADV 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 based on a total of 1166 data points 

the 2007-2011 ADV value would be the 4th highest value or 95 μg/m3 (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 PM10 NAAQS

The ADV 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 μg/m3

for Eagle River. This ADV is well below the LMP defined upper limit of 40 μg/m3. 

Summary

In summary each computational method described above shows that the 2007-11 PM10

ADVs for the Eagle River NAA are well below the annual and 24-hr LMP defined DVs. 

Using the most conservative approach the 24-hour ADV was found to be 95 ug/m3, and 

the annual ADV was found to be 17 μg/m3

. Based on the data quality and statistical 

results, 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 Option memo, EPA revoked the annual 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 sitespecific CDV. Determination of the site-specific 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 μg/m3 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 also determined that the PM10 data from the Eagle River monitors met quality criteria through 

December 31, 2009 in the NAAQS attainment determination rulemaking dated October 19, 2010 (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.