Advancements in a NIST-Traceable Quantitative Aerosol Generator 

Troy C. Pittenger

Cooper Environmental Services LLC

There is no NIST-Traceable calibration and audit 

standard to challenge PM CEMS

Evaluate and develop CES’ NIST-Traceable 

quantitative aerosol generator (QAG) to calibrate 

PM CEMS over a large range of PM concentrations.

• Focus research on the two main PM CEMS’

technologies, light scattering and beta 

attenuation while increasing the utility of the 

QAG. 

• Evaluate the QAG with light scattering and beta 

attenuation PM CEMS

• Identify possible issues–aerosol characteristics

• Modify the QAG to fit specific application needs

APPROACH

PROBLEM

Light scattering PM CEMS 

Initial evaluation

• Field evaluated with 3 different PM CEMS

• Highly linear relationship (r

2 > 0.95)

• PS-11 and QAG correlations very different

• Aerosol characteristics need adjustment

Recent advancements

• Δ particle size distribution

• Increase precision of nebulizer

RESULTS

Overall utility of the QAG

• The aerosol generated is much more predictable and 

precise using the new nebulizer (lower frequency). 

• The Overall size of QAG has been reduced

• Eliminate vapor correction and balance.

• The QAG can generate an aerosol that closely

matches the size distribution downstream of

environmental controls on a CFPP.

• The QAG had excellent comparison with beta

attenuation PM CEMS’ factory calibration.

• The QAG can be used to calibrated a beta 

attenuation monitor if the appropriate protocols 

are followed.

CONCLUSION

RESULTS (cont.)

1. Chuck Dene (EPRI)

2. Craig Clapsaddle (MSI)

3. Jamie Berg & John Cooper (CES)

4. Morgan Jones (FirstEnergy)

5. Baron, A, P., Willeke, K. (2005). Aerosol Measurement Principles, Techniques, and Applications. Hoboken, NJ: Wiley-Interscience.

6. Wen-Fu, T., Jenn-DerL., Yee-lin W. (2011). An Analysis of Extinction Coefficients of Particles and Water Moisture in the Stack after Flue Gas Desulfurization at a CoalFired Power Plant. AWMA, 61, 815-825.

REFERENCES/ACKNOWLEDGEMENTS

OBJECTIVES

OPERATING PRINCIPLE

Beta attenuation PM CEMS

Initial evaluation at FirstEnergy’s Bruce 

Mansfield Power Plant

• Near 1:1 comparison between factory

calibration and QAG on 3 different units

• Good comparison with 2 out of 3 PS-11

correlations

• Model developed explaining difference in 3

rd

PS-11 correlation (Beta # 3)

Key 

parameters CFPP QAG

Density (g/cm3) 2.0 1.98

Refractive 

index 1.50 1.49

MMD (μm) 4.0 0.5

0

10

20

30

40

50

0.3-0.50.5-0.70.7-1.01.0-2.52.5-5.05.0-10>10

%

o

f

t

o

t

al m

a

s

s

Particle diameter (um)

Particle Size of Old QAG

0

10

20

30

40

50

0.3-0.50.5-0.70.7-1.01.0-2.52.5-5.05.0-10>1

%

0

o

f

t

o

t

al m

a

s

s

Particle diameter (um)

Particle Size of New QAG Stack

Aerosol

Probe Filter

Probe Transport Filter Tape

PM Deposit Not 

Measured

PM Measured via BAM-Based 

CEMS Response

Gravimetric Measurement of

PM Deposit

Transport

y = 1.07x - 2.96

R2 = 0.985

0.0

20.0

40.0

60.0

80.0

0.00 20.00 40.00 60.00 80.00

Q

A

G

C

o

n

c (m

g/w

s

c

m)

Beta # 1 Conc (mg/wscm)

QAG Correlation

y = 1.169x + 0.3442

R2 = 0.9925

0.0

20.0

40.0

60.0

80.0

0.00 20.00 40.00 60.00 80.00

M

5 (m

g/w

s

c

m)

Beta # 1 Conc. (mg/wscm)

PS-11 Correlation

y = 1.05x - 1.35

R2 = 0.994

0.0

20.0

40.0

60.0

80.0

0.00 20.00 40.00 60.00 80.00

Q

A

G

C

o

n

c (m

g/w

s

c

m)

Beta # 2 Conc (mg/wscm)

QAG Correlation

y = 1.1937x - 1.9916

R2 = 0.9826

0

20

40

60

80

0 20 40 60 80

M

5 (m

g/w

s

c

m)

Beta # 2 Conc. (mg/wscm)

PS-11 Correlation

y = 1.06x - 0.364

R2 = 0.993

0.0

20.0

40.0

60.0

80.0

0.00 20.00 40.00 60.00 80.00

Q

A

G

C

o

n

c (m

g/w

s

c

m)

Beta # 3 Conc (mg/wscm)

QAG Correlation

y = 1.626x - 1.260

R2 = 0.981

0

20

40

60

80

0 20 40 60 80

M

5 (m

g/w

s

c

m)

Beta # 3 Conc. (mg/wscm)

PS-11 Correlation

• Solution of NIST-Traceable Concentration (Cs)

• Measured nebulization rate (R)

• Dried in NIST-Traceable flow (F)

• Produces a NIST-Traceable aerosol 

concentration (Ca)

• =

∗ 



0.4400

0.4500

0.4600

0.4700

0.4800

0.4900

0.5000

N

e

b

uliz

atio

n rate (g/min)

Time (hours)

Contiuous nebulization rate over time

Linear (5% interval) Linear (5% interval)

0.4% RSD