December 13,z}ll(revised April 5, 2012)

Note:

Subject: Data and procedure for handling below detection level data in analyzing various

pollutant emissions databases for MACT and RTR emissions limits

To: SPPD management and MACT rule writers

From: Peter Westlin, SPPD, MPG

Raymond Merrill, AQAD, MTG

This is a note regarding the handling of below detection level (BDL) data and in developing

representative detection level (RDL) data in evaluating the floor and setting emissions limits for

your NSPS, MACT, and RTR rule making projects. At the end of this note is a table which

includes several updates. The updates include corrected values for metals RDL, an easier to use

table (e.g., sample volume versus sampling time) and some pollutants not covered in the initial

table (e.g., HCI and filterable PM).

The RDL determination procedure

The revised procedure for determining an RDL starts with identifying all of the available

reported pollutant specific method detection levels for the best performing units regardless of

any subcategory (e.g., existing or new, fuel type, etc.). From that combined pool of data, we

calculate the arithmetic mean value. By limiting the data set to those tests used to establish the

floor or emissions limit (i.e., best performers), we believe that the result is representative of the

best performing testing companies and laboratories using the most sensitive analytical

procedures. V/e believe that the outcome should minimize the effect of a test(s) with an

inordinately high method detection level (e.g., the sample volume was too small, the laboratory

technique was insufficiently sensitive, or the procedure for determining the minimum value for

reporting was other than the detection level). We then call the resulting mean of the method

detection levels as the representative detection level (RDL) as characteristic of accepted source

emissions measurement performance.

The second step in the process is to calculate three times the RDL to compare with the calculated

floor or emissions limit. This step is similar to what we have used before in rulemaking

applications. 'We use the multiplication factor of three to approximate reduce the imprecision of

the analytical method until the imprecision in the field sampling reflects the relative method

precision as estimated by the ASME studyr that also indicates that such relative imprecision,

from 10 to 20 percent, remains constant over the range of the methods. For comparing to the

floor, if three times the RDL were less than the calculated floor or emissions limit (e.g.,

calculated from the UPL), we would conclude that measurement variability was adequately

addressed. The calculated floor or emissions limit would need no adjustment. If on the other

hand, the value equal to three times the RDL were greater than the UPL, we would conclude that

I 

1n.MAR¡' PHASE l, Precision of Manual Stâck Emission Measurements; American Society of Mechanical Engineers, Research Committee on

Industrial and Municipal Waste, February 2001,
the calculated floor or emissions limit does not account entirely for measurement variability. If

indicated, we substituted the value equal to three times the RDL for the calculated floor or

emissions limit which results in a concentration where the method would produce measurement

accuracy on the order of 10 to 20 percent similar to other EPA test methods and the results found

in the ASME study.

V/e determined the RDL for each pollutant using data from tests of all the best performers for all

of the final regulatory subcategories (i.e., pooled test data). 'We applied the same pollutantspecifrc RDL and emissions limit adjustment procedure to all subcategories for which we

established emissions limits. V/e believe that emissions limits adjusted in this manner better

ensure measurement variability is adequately addressed relative to compliance determinations

than did the procedure applied for the proposal that may have been based on data sets smaller

than seven tests and as few as one test. We also believe that the emissions testing procedures

and technologies available now and in the future will be adequate to provide the measurement

certainty sufficient for sources to demonstrate compliance at the levels of the adjusted emissions

limits when applied in the manner representative of this protocol.

We recommend that rule writers considering emissions limits for these pollutants review

the existing data sets and compare the RDL values used in earlier analyses with the revised

RDLs shown in the attached table. \ile believe that these revised values and the procedures

described in the table better reflect representative method capabilities and should be used

in data review for current rule development projects and Ín setting representative

emissions limits.

Results of MDL/RDL data analyses

We have collected data used for the boilers rule reconsideration and the proposed utility MACT

in light of the comments to review the effect of available larger pools of dioxin/furan emissions

as measured with Method 23 and the Hg emissions as measured with Method 29 of datafor these

sources. The expanded data set represents several hundred emissions tests used in the floor

calculations (i.e., best performers) for the boilers and utility rules. We presume that data for the

best performing units also reflect the capabilities of high quality testing companies and

laboratories. Further, the method detection levels calculated from larger data are more

representative of the inherent measurement variability both within and between testing

companies. V/e have also included data on the RDL values for the individual metals as

measured with Method 29 based on a similar assessment of data collected during method

development. The tables attached below express the results in two formats:

1) The mass of pollutant sample the method can detect quantitatively and is representative of the

method detection level (RDL) for the set of data collected for the specific rule development; and

2) The lowest concentrations that could be measured quantitatively for a range of sample

volumes for use in comparing to calculated UPL values and in setting applicable emissions

limits.
The first table represents a thorough review of D/F emissions data for both the boilers and utility

data sets. Not too surprisingly, the resulting values are similar but not identical. Our first

observation is that these calculated representative detection levels are generally greater in

magnitude than those calculated for the initial reviews and particularly for establishing new

source limits (i.e., for the single best performing unit). The second observation is that the RDLs

determined for the utility ICR data set are lower in magnitude than for the boiler data collected

during an earlier ICR project. We believe that the boiler data set includes some data reported

incorrectly (e.g., laboratory reporting limits rather than method detection limits) and that the

utility D/F data set includes fewer of these misreported data. As a result, we believe that the

RDLs determined from the utility D/F data set are more representative of current expected

measurement data quality. The application procedures described in the table reflect this

conclusion.

Also attached to this note is a spreadsheet example of the calculations used to develop these

values.

As rule writers collect additional data in the future and test methods and techniques improve,

there will be a need to assess new data for representative method detection capabilities. We will

prepare new procedures for you and your contractors to use as needed in future rule making

activities based on these findings. We will build on these procedures to reflect greater reliance

on the broadest set of measurement data available and provide default values to use when there

are only a few (e.g., fewer than seven) performance test results available for a source category.

Peter Westlin

Measurement Policy Group

Sectors Policies and Programs Division

Raymond Merrill

Measurement Technology Group

Air Quality Assessment Division

Addressees:

SPPD management

SPPD technical staff

cc:

Conniesue Oldham, MTG, AQAD

Jason Dewees, MTG, AQAD

Kim Garnett, MTG, AQAD

Kristen Benedict, MTG, AQAD

Robin Segall, MTG, AQAD
Summary of pollutant emissions representative method detection level analyses

and a regulatory emissions limit setting procedure

RDL

(ns)

3x

RDL

(ns)

3 x RDL Concentrations (ng/dscm)

I dscm test 2 dscm test 3 dscm test 4 dscm test 6 dscm test I dscm test

Ind. Boilers DÆ total

mass

Method 23)

5.6E-01 1.78+00 1.7E+00 8.5E-01 5.7E-01 4.3E-01 2.8E-01 2.tB-0t

Ind. Boilers TEQ

(Method 23)

8.28-02 2.58-01 2.sB-0t 1.38-01 8.3E-02 6.3F-02 4.28-02 3.tE-02

Utilities DIF total mass

(Method 23) 3.lE-01 9.28-0r 9.2F-01 4.6E-01 3.lE-01 2.3F-0t 1.sE-O1 1.2E-01

Utilities TEQ

Method 23) 3.6F-02 1.1E-01 l.lE-01 s.sE-02 3.78-02 2.88-02 l.8E-02 t.4E-02

RDL (ug) 3xRDL

lusl

3 x RDL Concentrations (us/dscm)

I dscm test 2 dscm test 3 dscm test 4 dscm test

HCVCI2 CMethod 264) 6.0E+1 1.8E+2 1.88+02 9.0E+01 6.0E+01 4.58+01

PM filterable (Method 5) 2.08+3 6.08+3 6.0E+03 3.08+03 2.0E+03 1.5E+03

Ind. Boiler He fMethod 29) 8.3E-01 2.58+00 2.lE+00 l.0E+00 7.tE-01 6.28-0r

120L test 240L test 360L test

HCVCL? Method 26) l.0E+01 3.0E'+01 2.58+02 I.3E+02 8.3E+01
Summary of pollutant emissions representative method detection level analyses and regulatory emissions limit setting

procedure for Method'29Metals usÍng Inductively Coupled Atomic Emission Spectroscopy or Atomic Absorption Analysis

Method 29 Metal

RDL

ICP/AES

or AA

fus)

3XRDL

ICP/AES or

AA

fus)

3 x RDL Concentrations (us/dscm)

I dscm tesl 2 dscm test 3 dscm test 4 dscm test

Antimony l.2E+01 3.5E+01 3.5E+01 1.7E+01 1.2E+01 8.6E+00

Arsenic 1.9E+01 5.7E+01 5.7E+01 2.98+0t 1.98+01 1.4E+01

Barium 8.0E-01 2.48+00 2.48+00 1.2E+00 8.0E-01 6.0E-01

Beryllium 1.1E-01 3.38-01 3.3E-01 1.7E-01 1.18-01 8.38-02

Cadmium 1.5E+00 4.5E+00 4.5E+00 2.38+00 l.5E+00 1.1E+00

Chromium 2.5E+00 7.58+00 7.5E+00 3.8E+00 2.5E+00 1.9E+00

Cobalt 2.5E+00 7.5E+00 7.5E+00 3.88+00 2.5E+00 1.9E+00

Copper 2.1E+00 6.3E+00 6.3E+00 3.2E+00 2.1E+00 1.6E+00

Lead 1.5E+01 4.58+01 4.58+01 2.38+Ol 1.5E+01 1.1E+01

Manganese 7.0E-01 2.18+00 2.18+00 1.1E+00 7.0E-01 5.3E-01

Mercury* 5.6E-01 t.7E+00 1.7E+00 8.4E-01 s.6E-01 4.2E-01

Nickel 5.48+00 1.6E+01 1.6E+01 8.1E+00 5.4E+00 4.1E+00

Phosphorus 2.7F+0t 8.1E+01 8.1E+01 4.lE+01 2.78+01 2.0E+01

Selenium 2.78+01 8.1E+01 8.1E+01 4.1E+01 2.78+01 2.08+01

Silver 2.6E+00 7.88+00 7.8E+00 3.9E+00 2.6F+00 2.0E+00

Thallium 1.4E+01 4.38+01 4.38+01 2.28+01 l.4E+01 1.lE+01

Zinc 8.0E-01 2.48+00 2.4F+00 1.2E+00 8.0E-01 6.08-01

*Mercury analyzedby Cold Vapor AA

RDL = Method derived regulatory detection limit based.

ICP/AES : Inductively Coupled Argon Plasma/Atomic Emission Spectroscopy

AA - Atomic Absorption Spectroscopy

GFAA: Graphite Fumace Atomic Absorption spectroscopy
Summary of pollutant emissions representative method detection level analyses and regulatory emissÍons lÍmit setting

procedure for Method 29 Metals using Inductively Coupled Plasma/lVlass Spectrometry or Graphite Furnace Atomic

Absorption Analysis

Method 29

Metal

RDL

ICP/]US

or GFAA

(us/dscm)

3XRDL

ICPNúS

or GFAA

(us/dscm)

Concentra tions ( ¡tg/ds c m)

I dscm test 2 dscm test 3 dscm test 4 dscm test 5 dscm test

Antimony 1.lE+00 3.3E+00 3.3E+00 1.7E+00 l.tE+00 8.3E-01 6.6E-01

Arsenic 4.0E-01 1.2E+00 t.2E+00 6.0E-01 4.0E-01 3.08-01 2.48-01

Barium** 8.0E-01 2.4F+00 2.48+00 1.2E+00 8.0E-01 6.0E-01 4.8E-01

Bervllium 8.0E-02 2.48-0t 2.48-01 t.2E-01 8.0E-02 6.0F-02 4.8F-02

Cadmium 3.0F-02 9.0E-02 9.08-02 4.5F-02 3.0E-02 2.38-02 1.8E-02

Chromium 3.0E-01 9.08-01 9.0E-01 4.58-01 3.0E-01 2.3F-Or l.8E-01

Cobalt 3.0E-01 9.08-01 9.08-01 4.5E-01 3.0E-01 2.38-Or l.8E-01

Copper** 2.lE+00 6.3E+00 6.3E+00 3.28+OO 2.lE+00 1.6E+00 1.3E+00

Lead 3.0E-01 9.0E-01 9.0E-01 4.5E-01 3.0E-01 2.38-01 l.8E-01

Manganese 3.0E-01 9.0E-01 9.0E-0r 4.5E-01 3.0E-01 2.38-01 r.8E-01

Mercury* 5.6E-01 1.7E+00 1.7E+00 8.48-01 5.68-01 4.28-0t 3.4E-0r

Nickel** 5.4E+00 l.6E+01 l.6E+01 8.1E+00 5.4E+00 4.tE+00 3.2E+00

Phosphorus** 2.78+01 8.lE+01 8.lE+01 4.lE+01 2.78+0t 2.0E+01 l.6E+01

Selenium 8.0E-01 2.48+00 2.48+OO l.2E+00 8.0E-01 6.0E-01 4.88-01

Silver** 2.68+00 7.8E+00 7.8E+00 3.98+00 2.6E+00 2.0E+00 1.6E+00

Thallium 3.0E-01 9.08-01 9.0E-01 4.58-01 3.08-01 2.38-01 1.8E-01

Zinc 8.0E-01 2.48+OO 2.4F+00 l.2E+00 8.0E-01 6.0E-0r 4.8E-01 *Mercury analyzedby Cold VaporAA ** Common metals analyzedby Inductively Coupled Plasma/AES or Flame Atomic Absorption Spectroscopy

RDL:Methodderivedregulatorydetectionlimitbased onl.25 dscmcollectedin I hour.

ICP/I{S : Inductively Coupled Argon Plasma/\4ass Spectrometry
GFAA: Graphite Fumace Atomic Absorption spectroscopy

Except for assessing boiler and CISWI data, we recommend that you select D/F data calculated from the utilities' data set rather than

for the industrial boilers in conducting the following analyses.

1. Calculate the UPL for your respective data set in units of pollutant mass Íts sampled by the test method (e.g., total ng of D/F,

total TEQ of DlF, ug of Hg).

2. Compare the 3xRDL mass value (shown in bold) to the calculated UPL. If 3xRDL mass < UPL mass, use the UPL value for

rulemaking. If 3XRDL > UPL, use the 3xRDL value for rulemaking. For source categories other than boilers, use the 3xRDL

D/F values shown above for Utilities.

3. Alternatively, you may calculate the UPL for your data set in units of pollutant concentration (ngldscm for D/F, ug/dscm for

Hg). If so, repeat steps I and2 selecting the concentration associated with the sample volume appropriate for your ICR or

regulatory decision. You may also determine to convert the values in the table to other emissions formats (e.g., lbilvfMBtu or

lb/lvtwh) for these comparisons.
Example spreadsheet:

(ng/dscm@Tpercent02)

mass(average TEQ(averageof

ofall congener all TEQ per

data in set)

2.79E-02

6.728-03

2.958-03

6.10E-03

1.16E-03

8.24E-03

3.08E-03

1.33E-03

9.64E-04

4.40E-03

1.82E-03

3.37E-03

7.8L8-04

2.3sE-03

1.61E-03

3.38E-03

2.24843

2.L98-O2

7.81E-04

4.26E-03

7.24E-02

1.45E-01

4.35E-01

congener in set)

6.24E-06

1.89E-06

2.70E-05

6.02E-05

1.06E-04

8.10E-04

3.00E-05

L.238-04

8.83E-05

4.33E-03

5.26E-0s

3.26E-04

6.93E-05

2.27E-04

4.6LE-O4

3.34E-03

2.18E-04

4.33E-03

1.89E-06

6.05E-04

1.03E-02

2.068-02

6.L78-O2

ng

lab mass

8.778-02

2.698-02

1.18E-02

2.448-02

4.63E-03

3.30E-02

1.238.0.2

5.32E-03

3.86E-03

L.76E-O2

7.298-03

1.35E-02

3.128-03

9.40E-03

6.438-03

1.35E-02

8.98E-03

ng

TEQ

2.s0E-05

7.55E-06

1.08E-04

2.4tE-O4

4.258-04

3.248-03

L.20E-O4

4.93E-04

3.53E-04

L.73842

2.toB-o4

1.30E-03

2.77E-04

9.09E-04

1.85E-03

t.348-02

8.73E-04

Total OCDD

Total

OCDF

L,2,3,4,6,7,9 HpCDD

7,2,3,4,6,7,8HpCDF

I,2,3,4,7,8HxCÐD

L,2,3,4,7,8HxCDF

L,2,3,4,7,g,g HpCDF

7,2,3,6,7,9HxCùD

L,2,3,6,7,8HxCùF

L,2,3,7,8PeCDD

l,2,3,7,8PeCDF

L,2,3,7,g,gHxCDD

L,2,3,7,g,gHxCDF

2,3,4,6,'l,8HxCDF

2,3,4,7,8PeCDF

2,3,7,8:ICDD

2,3,7,8--lCùt

max DL

min DL

mean DL

sum

RDL=EDLx2

RDLx3>floor?

8.778-02 L.73842

3.12E-03 7.55E-06

t.70E-02 2.42E-03

2.90E-01 4.ttÊ-02

5.80E-01 8.22E-02

L.74E+OO 2.478-OL