function and performance of a new real-time black carbon ... · 8 optical techniques: reflection...

Function And Performance Of A New Real-timeBlack Carbon Monitor During the 2003-2004

Fresno Study

2005 AAAR PM Supersites Program & Related StudiesFebruary 8, 2005, Atlanta, GA

5C-2

Kevin Goohs, Thermo Electron Corporation, Franklin, MADr. Andreas Petzold, Deutsches Zentrum fuer Luft- und Raumfahrt,

Oberpfaffenhofen, Wessling, GermanyScott Scheller, CARB, Fresno, CA

John Bowen, Dana Trimble, et al., DRI, Reno, NV

2

Basic Concepts

Black Carbon

• Major component of PM2.5

• Typically 25-50%, and up to 70% for PM2.5

• Three Classes of Carbon: 1. elemental or black (EC)

2. Organic (OC)

3. Carbonate (CC)

• Total Carbon (TC) = EC + OC + CC

Aerosol Monitoring – Black Carbon

3

Basic Concepts

Black Carbon

• EC: Anthropogenic Sources (mobile sources and PICs)

• OC: Anthropogenic Sources (1o and 2o aerosols)

• CC: Soil Related (<5% of TC)


4

Sampling Techniques

Non-Destructive and Indirect (Optical)• Filter Sample• Laser Transmission and/or Reflection• Method accuracy can be concentration and composition dependent


Destructive and Direct• Pre-fired Quartz or Glass Fiber used as a gravimetric sample.• Thermal Processes (methods vary in T, rate ∆T, Oxidation)• Carbon thermally evolved from sampled particulate• Similar TC results; EC & OC results vary from method to method

5

Sampling Techniques

Destructive (thermal optical transmittance and reflectance)

• Advantages: Recognized Reference Methods, TotalCarbon Measurements and breakdown of EC, OC, CC

• Disadvantages: Limited Time Resolution (typically 24-hr),Turnaround, Operating Costs, Laboratory Costs, and ECis an estimate method dependent

Aerosol Monitoring - Black Carbon

6

Sampling Techniques

Non-Destructive (laser/light transmittance and reflectance)

• Advantages: Low Operational Cost, Better TimeResolution, Increased Statistical Database, InstantaneousTurnaround (Index Reporting, Increased Knowledge of airshed characteristics), lower capital cost

• Disadvantages: Limited to EC, site specific with somemethods


7

Optical Techniques: Transmission (Gundel et al., 1984)


BCATN SIIATN σ=−=0

ln100

∗ σATN reported to range from 5 m2 g-1 to > 20 m2 g-1, depending on the type ofsampled aerosol (Liousse et al., 1993; Petzold et al., 1997)

** An analysis of attenuation measurements and independent measurements ofatmospheric black carbon via a thermal method showed that the σATN value isaffected by the fraction of exclusively light-scattering components of the aerosol(Petzold et al., 1997).

*** This conclusion was recently confirmed by a study on the Particle SootAbsorption Photometer (PSAP; Radiance Research Inc. Seattle, USA) (Bond et al.,1999).

8

Optical Techniques: Reflection (Bailey and Clayton, 1982)


• σREF aerosol study indicated marginal dependance (Kopp et al., 1999).

• σATN and σREF are different due to aerosol layer and filter matrix interaactions(Kopp et al., 1999)

• Concluded σATN and σREF differ from the specific absorption cross section σabs forairborne black carbon particles because airborne particles do not face any multiplescattering processes caused by a surrounding filter matrix.

• The deviation from σabs can reach 30% for aerosol deposited on membrane filter(Hitzenberger et al., 1993), while in the case of a fiber filter matrix it may become afactor of 2 and more (Petzold et al., 2001).

BCREF SRRREF σ2ln100

0

=−=

9


Example

inc ident rad ia tion

aeroso l layer

back scatteredrad ia tion

m ultip lere flec tions(d iffuse)

filte r m atrix

transm itted and fo rw ard -scatte red

rad ia tion

10


Development Goals

• Apply radiative transfer analysis of a particle loaded filter

• Account for multiple-scattering effects

• Apply knowledge of the optical field in the forward andbackward hemisphere of the aerosol-filter system.

• Develop a simple instrument for continuous black carbonmonitoring

11


Development

• Scattering phase function of blank and particle loaded filtersdetermined using a polar photometer

12


Development

• angular distribution of radiation for a blank filter with aerosol composition

• angular distribution into forward hemisphere independent of aerosol composition

• angular distribution into the back hemisphere is dependent with the absorbing aerosolreducing scatter and scattering aerosol increasing scattering w/respect to filter matrix.

13


Principal of Operation

θ0

θ1

θ2

θ0

θ1

θ2

• Aethelometer

• PSAP

• MAAP

Transmittance Only

Forward Scattering, Back Scattering, andTransmittance θ0 = 0°, θ1 = 130°, θ2 =165°

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Model 5012 MAAP Continuous Black Carbon Monitor: Multi-Angle Absorption Photometer

15

Thermo Model 5012 MAAP

Bench StudiesReno Aerosol Optics Study June 2002* MAAP shows good agreement with reference absorption over a wide range of absorption and ω0•Filter transmission methods (PSAP, aethalometer) require improved corrections for scattering effects, & filter loading (Sheridan et al., 2003)

0

50

100

150

200

0 50 100 150 200Reference Absorption (M m -1 @ 660 nm)

MA

AP

Abs

orpt

ion

(Mm

-1 @

660

nm

)

1:1 line

ap(MAAP) = 1.04*( ap(REF)) + 1.0,r2=0.99

σ σ

16

Bench StudiesReno Aerosol Optics Study June 2002


The plot to therightdemonstrates thestability of theMAAP with lowCarbon and highscatteringaerosol.

White Aerosol Runsat DRI Reno, NV June 2002

0.0

2.0

4.0

6.0

8.0

10.0

12.0

1 2 3 4 5 6 7 8 9

Bab

s (M

m-1

)Aethalometer 699nm MAAP 670 nm

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Bench StudiesFranklin, MA Collocated Precision Evaluation June 2003

MAAP 1 & 2 On Bench w/Room TSP and General Carbon Vane ExhaustFranklin, MA 6/10-6/12/2003 : 30 Minute Data Points

0

200

400

600

800

1000

1200

1400

1600

1800

20:00

22:00 0:0

02:0

04:0

06:0

08:0

010

:0012

:0014

:0016

:0018

:0020

:0022

:00 0:00

2:00

4:00

6:00

8:00

10:00

12:00

14:00

16:00

18:00

Time

BC

ng/

m3

Series1Series2

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Ambient StudiesFranklin, MA Collocated Precision Evaluation June 2003

Collocated MAAPs w/PM2.5 Inlet - Field Calibrated for Ta, Pa, and QaOvernight Collocation at Franklin, MA Shelter June 17-18th, 2003 : 30 Minute Data Points

0

100

200

300

400

500

600

700

800

900

14:30

15:30

16:30

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23:30 0:3

01:3

02:3

03:3

04:3

05:3

06:3

07:3

08:3

09:3

0

Time (hh:mm)

MA

AP

BC

Con

c (n

g/m

3)

MAAP 1MAAP 2

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Ambient StudiesFranklin, MA Collocated Precision Evaluation June 2003

Collocated MAAPs w/PM2.5 Inlet - Field Calibrated for Ta, Pa, and QaOvernight Collocation at Franklin, MA Shelter June 17-18th, 2003 : 30 Minute Data Points

y = 0.990x + 3.386R2 = 0.997

0

100

200

300

400

500

600

700

800

900

0 100 200 300 400 500 600 700 800 900

MAAP 1 (ng BC/m3)

MA

AP

2 (n

g B

C/m

3)

MAAP 2Linear (MAAP 2)

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Ambient StudiesFresno, CA Supersite Collocated Results

R e a l T im e 5 m in u te A v e ra g e M A A P B la c k C a rb o n a t F re s n o , C A 1 2 /8 -1 5 /2 0 0 3 b a s e d o n R a w D a ta

-2 0 .0 0

-1 0 .0 0

0 .0 0

1 0 .0 0

2 0 .0 0

3 0 .0 0

4 0 .0 0

16:4

8:00

20:3

8:00

0:37

:00

4:22

:00

8:11

:00

11:4

3:00

15:2

8:00

19:1

3:00

23:0

3:00

2:56

:00

6:48

:00

10:3

3:00

14:1

8:00

18:0

3:00

21:5

6:00

1:49

:00

5:42

:00

9:27

:00

13:2

0:00

17:0

5:00

20:5

5:00

0:49

:00

4:34

:00

8:19

:00

12:0

9:00

15:5

4:00

19:3

9:00

23:3

3:00

3:22

:00

7:07

:00

10:5

2:00

14:3

7:00

18:2

2:00

22:1

2:00

2:09

:00

6:02

:00

T im e o f D a y (h h :m m )

MA

AP

BC

(ug/

m^3

)

C B C _ 1 C B C _ 2

N o is e a n d n e g a tiv e v a lu e s a re a s s o c ia te d w ith M A A P 2 R e f le c t io n S ig n a ls e ith e r d iv e rg in g ra p id ly o r th e R e f le c t io n 1 6 5 in c re a s in g w h ile 1 3 5 c o n tin u e s to d e c re a s e .

A t le a s t th is c a n b e e x p la in e d . I t m a y b e re la te d to a n in te rm m ite n t c o n n e c tio n e r ro r s in c e M A A P 2 d id s h o w s o m e p o o r b e h a v io r n e a r th e s ta r t o f th e te s t a n d is a ls o in s ta lle d o n th e ro o f . V ib ra t io n m a y b e c a s u in g th e a s s u m e d p o o r c o n n e c tio n . F a c to ry c o n n e c to rs h a v e a lre a d y b e e n u p d g ra d e d to a v o id fu tu re p o o r c o n n e c tio n s .

M A A P 1 d o e s n o t s h o w th is p o o r b e h a v io r .

O th e rw is e , th e s e in s tru e m n ts a re t ra c k in g v e ry n ic e ly .

21


Ambient StudiesFresno, CA Supersite Collocated Results

Thermo Electron Model 5012 MAAP BC Monitor Hourly MAAP 2 vs MAAP 1 : Fresno, CA 12/10 - 12/31/2003

y = 1.09x + 0.01R2 = 0.99

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00

MAAP 1 (ug/m3)

MA

AP

2 (u

g/m

3)

22


Ambient StudiesFresno, CA Supersite EC Data Comparison

MAAP & Elemental Carbon Time Series Fresno, CA 1/10 - 8/7/2004

0.0000

0.5000

1.0000

1.5000

2.0000

2.5000

3.0000

3.5000

4.0000

1/10/2

004

1/17/2

004

1/24/2

004

1/31/2

004

2/7/20

042/1

4/200

42/2

1/200

42/2

8/200

43/6

/2004

3/13/2

004

3/20/2

004

3/27/2

004

4/3/20

044/1

0/200

44/1

7/200

44/2

4/200

45/1

/2004

5/8/20

045/1

5/200

45/2

2/200

45/2

9/200

46/5

/2004

6/12/2

004

6/19/2

004

6/26/2

004

7/3/20

047/1

0/200

47/1

7/200

47/2

4/200

47/3

1/200

48/7

/2004

Date (mm/dd/yyyy)

BC

& E

C D

ata

(mic

rogr

ams

per c

ubic

met

er)

ECTC MAAP

23



MAAP BC and EC Time Series within 2σ Uncertainty

0.0000

0.5000

1.0000

1.5000

2.0000

2.5000

3.0000

3.5000

4.0000

4.5000

1/4/20

041/1

1/200

41/1

8/200

41/2

5/200

42/1

/2004

2/8/20

042/1

5/200

42/2

2/200

42/2

9/200

43/7

/2004

3/14/2

004

3/21/2

004

3/28/2

004

4/4/20

044/1

1/200

44/1

8/200

44/2

5/200

45/2

/2004

5/9/20

045/1

6/200

45/2

3/200

45/3

0/200

46/6

/2004

6/13/2

004

6/20/2

004

6/27/2

004

7/4/20

047/1

1/200

47/1

8/200

47/2

5/200

48/1

/2004

BC & EC Data

Dat

e (m

m/d

d/yy

yy)

EX_low EC_up MAAP

24



MAAP vs FRM DRI ECFresno, CA 1/10 - 8/7/2004

y = 0.95x - 0.04R2 = 0.97

0

0.5

1

1.5

2

2.5

3

3.5

0.0000 0.5000 1.0000 1.5000 2.0000 2.5000 3.0000 3.5000 4.0000

EC (micrograms per cubic meter)

BC

(mic

rogr

ams

per c

ubic

met

er)

25

• Insensitive to Aerosol Properties• Accounts for Scattering Artifacts of non-carbon aerosol• Excellent Performance at DRI Bench Study, June ’02

Model 5012 MAAPFeatures and Benefits

• Automatic Filter Change, temporal and mass loading driven• Data Output via Analog, Serial, and Display• Long term networking ability• Microprocessor controlled, Quality Assurance Features

• 1-yr data storage and minimum 6 month filter tape• Excellent candidate for ambient light absorption studies for

visibility monitoring (Bext = Babs + Bscat)

26

• Analog I/O Expansion Board: Can be used withmeteorological sensors

Model 5012 MAAPFeatures and Benefits

• Filter Strip Printer for quasi-Chain of Custody• Foil Separation for limited filter stain speciation

• Significant mass loading for post collectionanalysis

27

Ambient• Air Toxic Monitoring• AQ Index Reporting• Fenceline Monitoring• Air shed Characterization• Visibility research• Tropospheric Carbon

Studies

Model 5012 MAAPApplications

28

Conceptual SourceMonitoring• CEM w/ Dilution

Probe• Combustion

Efficiency Indicator• Diesel Shop Testing

Model 5012 MAAPApplications

…Research, Development, &Application

29

THANK YOU

Dr. Judy Chow

Dana Trimble

John Bowen

Scott Scheller

Dr. Andreas Petzold

function and performance of a new real-time black carbon ... · 8 optical techniques: reflection...

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