Cooper Environmental Services 1

Why Do We Need a QAG?

Multi-metal CEMS would otherwise 

depend on Method 29 for certification, 

validation, audits and RATA.

PM CEMS/CPMS certifications with PS 

11 and Method 5 are difficult, costly and 

unreliable near detection limit - Requires 

feed and AP control modifications

“Generating PM concentrations over the 

measurement range is a PAIN”

Should be useful in new method 

development for other species CEMS
Cooper Environmental Services 2

QAG History and Major Milestones

 1997: Lilly Metals CEMS Development project 

 1993 to 2004: Difficulties with Method 29

 2004: QAG Developed for Lilly Xact Certification 

 2005: Applied for patent

 2006:EPA Approved QAG for Metals Audit

 2008: Lilly QAG extended to PM for Sigrist CEMS

 2008: EPRI sponsored test of BAM CEMS

 2009: EPRI PM QAG improvement project

 2011: PM QAG field tested on CFPP
Quantitative Aerosol Generator (QAG)

Cooper Environmental Services 3

Solution Emission Rate (R)

(grams solution per minute) 

Analyte Solution Concentration (S)

(micrograms per grams solution)

Carrier/Drying Air Flow (F)

(cubic meters per minute) 

Quantitative Aerosol Conc. (C)

(micrograms per cubic meter)

C = RS/F 

Traceable to NIST 

Standards

A device that generates an aerosol whose concentration 

is independently traceable to NIST standards.

G

e

n

e

r

a

t

e

Dilute
Cooper Environmental Services 4

Key Metals QAG Components

Nebulizer Solution Control and 

Measurement

Nebulizer Carrier 

Air Control

Droplet Size 

Control

Focused 

Transport

Drying 

Chamber

Quantitative Emissions (mg/min. and mg/dscm)

Drying/Carrier Air

Drying/Carrier Air
Cooper Environmental Services 5

Quantitative Aerosol Generator for Metals 

Drying Chamber

Bubblers

Pump

Reservoir

Balance Nebulizer

Droplet Size 

Control

Focused 

Transport
Cooper Environmental Services 6

QAG EMISSIONS OVER 13 HOURS

y = -0.1452x + 1662.7

R

2

 = 0.999

1,380

1,400

1,420

1,440

1,460

1,480

1,500

1,520

1,540

800 1,000 1,200 1,400 1,600 1,800 2,000

Minutes

M

a

s

s (g)

0

10

20

30

40

50

60

70

80

90

100

Zin

c

C

o

n

c. μ

g/m3

Xact Measured Zinc Conc. (μg/m3)

Measured NIST

Solution Loss Rate (R)

QAG Calculated 

Emissions (CA)

13 hours
Prototype MM/PM QAG

Cooper Environmental Services 7

Drying Chamber

Frequency Generator

Amplifier

Heater Controls

EPA-Approved QAG for audits of

Multi-metal CEMS at a specific 

incinerator – M29 not required
Cooper Environmental Services 8

Note Difference 

Between Aerosol

Generation

Transport

Utility
Cooper Environmental Services 9

Qag, Xact, XFM Laboratory Test Arrangement
Cooper Environmental Services 10

Qag, Xact, XFM Laboratory Test Arrangement
Cooper Environmental Services 11

Solution Emission Rate Measured 

During Each Test

Solution Reservoir

Balance

Pump
Cooper Environmental Services 12

QAG EMISSIONS RATE OVER 13 HOURS

y = -0.1452x + 1662.7

R

2

 = 0.999

1,380

1,400

1,420

1,440

1,460

1,480

1,500

1,520

1,540

800 1,000 1,200 1,400 1,600 1,800 2,000

Minutes

M

a

s

s (g)

0

10

20

30

40

50

60

70

80

90

100

Zin

c

C

o

n

c. μ

g/m3

Xact Measured Zinc Conc. (μg/m3)

Measured NIST

Solution Loss Rate (R)

QAG Calculated 

Aerosol Conc. 

(CA)

13 hours
Cooper Environmental Services 13

Flow Diagram for Lilly’s PM & MM 

CEMS Field Testing With QAG

~700 lpm

QAG Spike

Sigrist Photometer

CES Xact MM CEMS
Cooper Environmental Services 14

Spiking Flows at Lilly Stack 

Stack 

Gas

QAG Aerosol 

(~50 lpm)

CEMS/XFM

~12 m to CEMS

~0.3 m

Port

~700 lpm
Cooper Environmental Services 15

QAG + XACT VARIABILITY COMPARED TO 

METHOD 29 PRECISION

Arsenic (3.5 %RSD)

0

10

20

30

40

50

60

70

4/9 0:00 4/9 12:00 4/10 0:00 4/10

12:00

4/11 0:00 4/11

12:00

4/12 0:00 4/12

12:00

C

o

n

c . ( μ

g / d

s

c

m )

N=250

Equivalent Method 29 Expected Data Scatter

Three Days

Even with stack conc. variability, may still 

pass M301 criteria with dynamic spiking
Cooper Environmental Services 16

Combined QAG & XACT PRECISION

- Spiked Stack Gas -

0

1

2

3

4

As Cd Cr Pb Hg

%

R

S

D
Cooper Environmental Services 17

LABORATORY:

PRECISE, ACCURATE AND LINEAR

XFM VS. QAG CHROMIUM

y = 0.966x - 1.9344

R

2

 = 0.9903

0

20

40

60

80

100

120

140

0 50 100 150

QAG (μg/dscm)

X

F

M

(

μ

g

/

d

s

c

m

)

Precise/Linear: R2 = 0.990

Accurate: Slope = 0.966

29 XFM 

Measurements
Cooper Environmental Services 18

XFM Field Linearity (Cr, As, Hg, Pb)

- QAG Spiked Stack Gas -

Mercury

y = 1.036x - 1.803

R

2

 = 0.991

0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140

Reference Conc. (μg/dscm)

X

F

M (μ

g/d

s

c

m)

n=26

Chromium

y = 1.042x - 1.605

R

2

 = 0.994

0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140

Reference Conc. (μg/dscm)

X

F

M (μg/d

s

c

m)

n=26

Arsenic

y = 1.067x - 2.716

R

2

 = 0.994

0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140

Reference Conc. (μg/dscm)

X

F

M (μ

g/d

s

c

m)

n=26

Lead

y = 1.068x - 2.079

R

2

 = 0.991

0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140

Reference Conc. (μg/dscm)

X

F

M (μ

g/d

s

c

m)

n=26

N = 26

Slope: 1.04 Slope: 1.07

Slope: 1.04 Slope: 1.07
Cooper Environmental Services 19

y = 0.999x - 0.103

r = 0.998

n = 675

0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140

Theoretical Concentration (μg/dscm) 

M

e

a

s

u

r

e

d

C

o

n

c

e

n

t

r

a

tio

n (μ

g/d

s

c

m) a

Cr

As

Hg

Pb

Cd

QAG MM Linearity Demonstration

All data included

135 runs
Cooper Environmental Services 20

XFM RELATIVE ACCURACY 

– QAG Spiked Stack Gas -

0

5

10

15

20

AS CD CR PB HG

R

ela

tiv

e

A

c

c

u

r

a

c

y

EPA Requires less than 20%
Cooper Environmental Services 21

Extending QAG From Metals 

to PM Range

 Increase droplet size and emission rates 

 Increase PM salt solution concentration

 Increase power and frequency of nebulizer

 Increase carrier air flow to meet needs of 

PM CEMS
Stack and QAG Aerosol Size 

Distributions

Cooper Environmental Services 22

Stack Aerosol

MMD ~ 1.5μm

QAG Aerosol

MMD ~ 0.6μm

Stack 

Sample 1

Stack 

Sample 2

QAG Aerosol

MMD ~ 0.6μm

0.5 μm

0.5 μm

0.5 μm
Sigrist, QAG & Method 5 Correlations

Cooper Environmental Services 23

Method 5 and Sigrist

M

Sigrist (mg/dscm)

e

t

h

o

d

5 (m

g

/

d

s

c

m)

Sig

ris

t (m

g

/

d

s

c

m)

Sigrist vs QAG

QAG (mg/dscm)
Cooper Environmental Services 24

Demonstrated Performance for Prototype PM QAG

Criteria Goal Demonstrated

 Accuracy (relative % diff.) 10% 8%

 Precision (RPSD) 10% 2%

 Linearity (predicted vs measured, mg/dscm) 

– Slope 1.0 ± 0.1 0.93

– Intercept ±1 -0.66

– R2 >0.85 0.99

 Repeatability (RPSD) 10% 5%

 Traceable to NIST Stds. Yes Yes

 Max. conc. at 700 lpm (mg/dscm) 20 mg/dscm 22 mg/dscm

 Max. conc. at 55 lpm (mg/dscm) NA 290

 Transportable Yes Yes

All Lilly Goals Met
Preliminary PM QAG Feasibility study: 

Interface with PM CEMS Probe

Cooper Environmental Services 25

Probe Nozzle

4” SS Interface “T”
Cooper Environmental Services 26

y = 1.1981x - 3.0665

R2 = 0.9797

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00

Q

A

G

C

o

n

c. (

m

g

/

m

3

)

Beta PM CEMS Conc. (mg/m3)

Linearity of QAG with 90% recovery rate and Beta PM CEMS

N = 18

Y = 1.19X – 3.1

R squared = 0.98

Prototype PM QAG 

2008 BAM CEMS Challenge
Cooper Environmental Services 27
PM QAG Linearity Determined With 

Total Capture Tests

Cooper Environmental Services 28

Gravimetry

Y = 1.002X - .096

R squared = 0.998

X-Ray Fluorescence

Y = 1.025X – 0.012

R squared = 0.996
Cooper Environmental Services 29

Total Capture Aerosol Concentration Equations

C RTC V

Q

KI  ( )/

C Ma Mb V

G

KI  (  )/

C DI Ad V

X

KI

 (1.31 )/

QAG Predicted

Gravimetric 

Measurement

XRF KI Measured

Solution loss rate

Time

Salt Sol. conc.

Carrier air 

volume

Filter mass – after and before 

Iodine aerial density Deposit area

KI Factor
Cooper Environmental Services 30

XRF KI Compared to Gravimetric Mass

y = 1.0342x

R

2

 = 0.9998

0

100

200

300

400

500

600

0 50 100 150 200 250 300 350 400 450 500

Gravimetry (mg/sample)

X

R

F

KI (m

g/s

a

m

ple)

4.7 cm diameter filters

20X25 cm filters

N =32

Y = 1.03X

R squared = 0.9998

Gravimetry (mg/dscm)

X

R

F

KI (

m

g

/

d

s

c

m

)
Cooper Environmental Services 31

Linearity of QAG Emission Rates 

(mg/min.)

y = 0.927x

R

2

 = 0.9982

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00

QAG Predicted (mg/min.)

M

e

a

s

u

r

e

d (m

g/min.)

N = 38

Total Capture (1.3 m U-tube)

Salt: KI, K2SO4

Range: 0.04 to 16 mg/min.
Cooper Environmental Services 32

Linearity of QAG Aerosol 

Conc. (mg/dscm)

y = 0.9266x - 0.6587

R

2

 = 0.998

0

50

100

150

200

250

300

350

0 50 100 150 200 250 300 350

Total Capture (1.3 m U-tube, 

4 m Lilly Transport)

Salts: KI, K2SO4

Total flow: 55 lpm

Range: 0.5 to 290 mg/dscm

If flow were 700 lpm –

Range: 0.04 to 23 mg/dscm

If flow were 10 lpm –

Range: 3 to 1,600 mg/dscm

N = 40
Key PM QAG Improvements

 PO-210 Charge neutralizer

 Transport system to porous tubing

 Transport interface polished and heated

 Custom design aerosol generation assembly

 Change salt used for PM generation

Cooper Environmental Services 33
Cooper Environmental Services 34

Schematic of Modified QAG

Po210 Source

Nebulizer

Focused 

Aerosol transport/drier

Generator Module

Control Module
Cooper Environmental Services 35

PM QAG With Module Doors Closed

Nebulizing Module

Charge Neutralizer

Control 

Module

Porous Metal Aerosol 

Focusing Guides
Cooper Environmental Services 36

Focused QAG Aerosol
New QAG Total Capture QA Setup

Cooper Environmental Services 37

Physical

Trap

Mass Flow

Meter Valve Pump

QAG

To Control

Box

Charge

Neutralizer

Drying

Chamber

Heater

Make up Air

Filter Holder

Total 

Capture 

Filter
Example PM CEMS Interface Setup

Cooper Environmental Services 38

Mass Flow Meter

Dilution Air PM 

Filter

Exhaust PM 

Filter

Pump

PM CEMS Probe

Airflow

Same Location as 

Total Capture Test 

Filters
New QAG Laboratory Spiking of 

TSI/MC DustTrack

Cooper Environmental Services 39

TSI/MC CEMS 

QAG PM CEMS 

Interface 

QAG Nebulizer Module

QAG Control Module

QAG Probe Cover
Laboratory Spiking of TSI/MC 

DustTrack with New QAG

Cooper Environmental Services 40

Y = 1.17 – 0.80

R squared = 0.999

Factory Calibration
On-Stack Field Validation/QA Setup

Total capture 

filter holder

Cooper Environmental Services 41
Initial QAG On-Stack Field Linearity

(Total Capture vs QAG) 

y = 0.968x + 0.186

R2 = 0.991

0

2

4

6

8

10

12

14

16

0 2 4 6 8 10 12 14 16

To

t

a

l

c

a

p

t

u

r

e

C

o

n

c. (

m

g

/

s

c

m

)

QAG Conc. (mg/scm)

N = 16

Cooper Environmental Services 42
QAG On-Stack Field QA 

Total Capture Percent Recovery

Recovery at Different Concentrations

 3.5 mg/dscm 99.3%

 6.5 mg/dscm 102%

 13.0 mg/dscm 99.3%

Recovery Over 14 Days (N = 5) 97.6 ± 2.8

Cooper Environmental Services 43
Summary of QAG On-Stack Field Tests

Key Parameters Goal Actual

 Traceable to NIST standards Yes Yes

 Percent recovery >98% 98.8

 Linearity:

– Slope 1.00±0.05 0.97

– Intercept (mg/scm) < 0.1 0.19

– Correlation coefficient ≥0.95 0.99

 PM Range (mg/scm): >12 >14 

 Repeatability (14 days) 10% 8.4%

Cooper Environmental Services 44
QAG On-Stack Field Evaluation Setup

Cooper Environmental Services 45
On-Stack Field study setup

Thermo Interface PCME Interface

PM 

CEMS

Cooper Environmental Services 46
QAG Field Summary

QAG setup and QA took 2 days

98% average PM recovery over 14 days

 Recovery was stable over 14 days

Generated nominal PM Concentration 

levels at 0, 3.5, 6.5, and 14.5 mg/scm

QAG interfaced/challenged 4 different 

PM CEMS probes with minimal 

modifications

Cooper Environmental Services 47
Future Developments & Applications

 Optimize QAG to better simulate stack aerosol

 Validate QAG-Based alternatives to PS-11, etc.

 Apply QAG to Method 301 alternative method validation to 

meet Non-Mercury HAP Metal compliance demonstration

 Filter spiking for method validation – Jeff Ryan

Key 2011 Method 301 Modifications

 No longer requires comparison to RM Methods

 QAG can be used to determine precision, bias and linearity 

with dynamic spiking and sequential sampling

 Method 301/QAG ~ Effort required to conduct a 

Performance Specification 

Examples of Possible QAG Applications

Cooper Environmental Services 48