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
Quantitative Aerosol Generator (QAG)

Cooper Environmental Services 2

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 3

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 4

Quantitative Aerosol Generator for Metals 

Drying Chamber

Bubblers

Pump

Reservoir

Balance Nebulizer

Droplet Size 

Control

Focused 

Transport
Cooper Environmental Services 5

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 6

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 7

Note Difference 

Between Aerosol

Generation

Transport

Utility
Cooper Environmental Services 8

Qag, Xact, XFM Laboratory Test Arrangement
Cooper Environmental Services 9

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

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 11

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 12

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 13

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 14

Combined QAG & XACT PRECISION

- Spiked Stack Gas -

0

1

2

3

4

As Cd Cr Pb Hg

%

R

S

D
Cooper Environmental Services 15

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 & Xact MM Linearity Demonstration

All data included

135 runs
Cooper Environmental Services 16

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%