July 23, 2012

Reply to

Attn Of: OEA-095

MEMORANDUM

SUBJECT: Eugene-Springfield PM10 NAAQS and LMP Determination

FROM: Chris Hall

ECU Air Data Analyst, OEA

TO: Kristin Hall

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 Eugene-Springfield PM10

Non-attainment Area (NAA). Based on a statistical analysis the Eugene-Springfield PM10 NAA

meets the attainment and design value criteria necessary to qualify for the Limited Maintenance 

Plan optioni

. 

Background

On January 13, 2012, the State (ODEQ) submitted to EPA for approval the Eugene-Springfield 

PM10 LMP and requested that EPA redesignate the Eugene-Springfield NAA to attainment for 

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

NAAQS, and in the most 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.

Utilizing data through December 31, 2008, ODEQ showed that the NAA had been attaining the 

PM10 NAAQS and that the 24-hr and annual ADVs were below the 24-hr and annual LMP 

defined DVs. The 2001 LMP option memo defines that the most recent five years of data needs

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

the Eugene-Springfield PM10 NAA attains the PM10 NAAQS for 2009-11 and to determine if the 

LMP option is an appropriate approach based on a DV analysis for 2007-11.

Data Quality Review

A data quality review of the most recent two years of data has also been performed and has been 

found to meet the criteria specified in 40 CFR part 58 for bias, and performing the required 

number of verifications and audits. Bias results are based on flow rate verifications and were 
found to be less than 1% for 2007-11 which greatly exceed stated quality objectives. Based on 

these results, the PM10 data is of appropriate quality and is usable for determining LMP 

eligibility for the 2007-11 timeframe.

Data Completeness

In the 3rd quarter of 2009, data completeness was 73% with 7 missing sample days for the Key 

Bank PM10 site. For showing NAAQS attainment, EPA regulationiv allows for substitution for 

quarters with less than 75% data completeness if approved by the Regional Administrator and in 

accordance with EPA guidancev

. For this LMP review, data substitution was utilized to 

determine a 24-hr and annual ADV to compare to the respective LMP defined DVs. 

The optimal source for data substitution is from a collocated monitor, but as a collocated PM10

monitor has not been sited at Key Bank, this is not an available substitution option. The second 

option is to substitute the highest recorded value from the same quarter for the missing data 

points. This high substitution value can be from any of the years within the data set of interest 

(i.e., 3rd quarter 2007, 2008, 2009, 2010, or 2011). 

For 3rd quarter 2009, the highest substitute value found was 58 μg/m3, which was recorded on 

September 6, 2011. This value of 58 μg/m3 will be substituted for each of the 7 missing days in 

2009, in computing both the expected number of exceedances (EE) for 2009-11 and the LMP 

DV. 

NAAQS Attainment

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

discusses only attainment of 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. Appendix K 

also requires three consecutive years of complete data to make an affirmative attainment 

determination. A year is deemed complete if each of the four quarters has at least 75% data 

completeness. For calendar years 2009 through 2011, the Key Bank site met this completeness 

requirement with the exception of 3rd quarter 2009, which only had a completeness rate of 73%. 

As no exceedances of the 24-hour standard were recorded in the 2009-11 timeframe, the EE for 

Eugene-Springfield is zero. This is also true when performing data substitution for the seven 

missing run days in 3rd quarter 2009, where substituting the high value of 58 μg/m3 from 

September 6, 2011, still yields an EE of zero.

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 discussed. The advantage of the Upper 10% Tail 

Distribution method is that this statistical approach only takes into account the high 

concentration data values which are the most important when determining a DV. 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 DV estimation methods below utilized data from the full five years rather than an overall 

average of the running 3-yr DV averaging periods. This provides a larger and more robust data 

set for computing DV statistics. To qualify for the LMP option the 24-hr ADV must be below 

the 98 μg/m3

, and the annual ADV must be below the 40 μg/m3i. 

Upper 10% Tail Distribution

This method is a straight statistical equation derived by OAQPS and only uses the high 10% of 

data values.

Equation 1: ADV = X90 + 3.612(U90 - X90)

Where

X90 = 90th percentile value = value 54 = 28.0 μg/m3

U90 = mean of the upper 10% of values = 42.9 μg/m3

Total Data points = 537 including substituted values for missing days

Solving equation 1 with the provided values yields an ADV of 82 μg/m3.

Method 4 – Tabular Estimation Method

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

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

The 2007-2011 PM10 data set for Eugene-Springfield contains 537 data points including 

substituted points. Based on the above table the LMP DV value would be the second highest 

value or 78 μg/m3 (see table below). 
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 15 μg/m3 for EugeneSpringfield, which is well below the LMP defined DV of 40 μg/m3

. Substituting 58 μg/m3 for 

the 7 missing sample days for 2009 still yields an ADV of 15 μg/m3.

Summary

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

for the Eugene-Springfield 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 82 ug/m3, and the annual 

ADV was found to be 15 μg/m3. Based on the data quality and statistical results, the EugeneSpringfield NAA meets the attainment and design value criteria to qualify for the LMP option.

 i

‘LMP Option for Moderate PM10 Non-attainment Areas’, August 9, 2001, as approved by Lydia Wegman designee, ii Subsequent to the issuance of the 2001 LMP Option memo, EPA revoked the annual PM10 standard. 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 See 40 CFR Part 50, Appendix K, §2.3(b) v In this case we follow the EPA ‘Guideline on Exceptions to Data Requirements for Determining Attainment of 

Particulate Matter Standards’ EPA 450/4-87/005, April 1987.

Site Monitor ID Collection Date 24-hr Avg Rank

Key Bank 41-039-0058-81102-1 03-Feb-2009 80 1

Key Bank 41-039-0058-81102-1 05-Feb-2007 78 2

Key Bank 41-039-0058-81102-1 02-Feb-2007 69 3

Key Bank 41-039-0058-81102-1 06-Sep-2011 58 4

Key Bank 41-039-0058-81102-1 18-Jul-2009 58 4

Key Bank 41-039-0058-81102-1 21-Jul-2009 58 4

Key Bank 41-039-0058-81102-1 24-Jul-2009 58 4

Key Bank 41-039-0058-81102-1 27-Jul-2009 58 4

Key Bank 41-039-0058-81102-1 05-Aug-2009 58 4

Key Bank 41-039-0058-81102-1 11-Aug-2009 58 4

Key Bank 41-039-0058-81102-1 28-Sep-2009 58 4

Key Bank 41-039-0058-81102-1 15-Sep-2008 56 12

Key Bank 41-039-0058-81102-1 22-Jan-2009 55 13

Key Bank 41-039-0058-81102-1 12-Dec-2009 49 14