Laser-induced incandescence (LII) for the measurement of atmospheric black carbon

(1)

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Laser-induced incandescence (LII) for the measurement of atmospheric black carbon

(2)

Measurement Science and Standards

La se r-induc e d I nc a nde sc e nc e (LI I )

for t he M e a sure m e nt of

At m osphe ric Bla ck Ca rbon

Greg Smallwood

Council on Optical Radiation Measurements 2012 Annual Technical Conference

29 May – 1 June 2012

Ottawa, ON, Canada

(3)

Ack now le dge m e nt s

Development of LII

• Dave Snelling, Kevin Thomson, Fengshan Liu, Bob Sawchuk,

Dave Snelling, Kevin Thomson, Fengshan Liu, Bob Sawchuk,

Dan Clavel, Daniel Gareau

- NRC Measurement Science and Standards

At

h i M

t

Atmospheric Measurements

• John Liggio, Mark Gordon, Jeffrey Brook, Shao-Meng Li, Craig

Stroud, Ralf Staebler, Gang Lu, Patrick Lee

- Environment Canada, Atmospheric Science and Technology

Directorate

Atmospheric Inventory Data

• Brett Taylor

(4)

Out line

Background

Laser-induced Incandescence (LII)

Laser induced Incandescence (LII)

High-Sensitivity Laser-induced Incandescence (HS-LII)

Comparison to other Instruments

p

Applications

Summary

(5)

Bla ck Ca rbon (BC) a nd Pa r t ic ulat e

M at t e r (PM )

(

)

Black carbon (BC) is a major component

of the particulate matter (PM) emissions

from hydrocarbon-fuelled combustors

y

• diesel and gasoline internal combustion

engines, gas turbine engines, powerplants,

furnaces & boilers, etc.

10 nm

Nonvolatile Primary Particle

Other PM components include

• condensed hydrocarbons

• sulphates, nitrates, and trace metals

p

,

Volatile Coating on a Nonvolatile Aggregate

PM is implicated in health effects and in

climate change

• cardiovascular, lung function, immune

Volatile Nucleation Mode Particle Nonvolatile Aggregate Particle Particle

,

g

,

response, cancers

(6)

T EM I m a ge s of Bla ck Ca rbon Sa m ple d

From a Fla m e

in-flame

ethylene

BC

(7)

T EM I m a ge s of N a nopa r t icle s

Assumption:

in-flame in-flame post-flame oxidized ethylene methane diesel ambient

BC

=

BC

=

BC

=

BC

= …

• particulate matter properties of

interest:

– concentration

– active surface area

i

ti l di

t

– primary particle diameter

distribution

– aggregate size distribution

– optical properties

optical properties

– volatile fraction

– composition

(8)

T EM I m a ge s of N a nopa r t icle s

Reality:

in-flame in-flame post-flame oxidized ethylene methane diesel ambient

BC

≠

BC

≠

BC

≠

BC

≠ …

• particulate matter properties of

interest:

– concentration

– active surface area

i

ti l di

t

– primary particle diameter

distribution

– aggregate size distribution

– optical properties

optical properties

– volatile fraction

– composition

(9)

Cha lle nge s for Opt ic a l Dia gnost ic s of

Bla ck Ca rbon

Need to know the optical properties of the particles

• composition of particle

- nascent soot (lower C/H ratio; potentially liquid)

- mature soot/BC (high C/H ratio; solid)

- mature soot/BC coated with condensed materials (organics, etc.)

• absorption enhancement

- coatings

coatings

• absorption by coating

• focusing of light by coating

• changes induced by optical technique (not always non-intrusive)

g

y p

q

(

y

)

- sublimation/evaporation

- internal structure changes that affect absorption/scattering properties

- fragmentation of particles

fragmentation of particles

(10)

Out line

Background

Laser-induced Incandescence (LII)

Laser induced Incandescence (LII)

High-Sensitivity Laser-induced Incandescence (HS-LII)

Comparison to other Instruments

p

Applications

Summary

(11)

La se r-I nduc e d I nc a nde sc e nc e (LI I )

high selectivity technique for measuring black carbon

• soot, refractory carbon, elemental carbon, carbon black

measures (for an ensemble of particles):

• mass concentration, volume concentration, active surface

area, primary particle diameter

b

d

t

(20

/

3 20 /

3

50

200 • broad measurement range (20ng/m

3 – 20g/m

3 mass

; 50 – 200

m

2

_/g

_{active surface area}

_{; 5-50 nm}

_{primary particle diameter}

₎

(12)

T im e -Re solve d La se r-I nduc e d

I nc a nde sc e nc e

Laser Detector [ ] 3500 K Temperature Incandescence a ndescence T [K] Incandescence 0 0.2 0.4 0.6 0.8 1 inc a 0 300 K t [µs]

(13)

Aut o-Com pe nsat ing LI I (AC-LI I )

Traceable physics-based calibration procedure

• using calibrated integrating sphere as a spectral radiance source

• not correlation

against another aerosol instrument

Two-color pyrometry coupled with LII to determine the

time-resolved particle temperature

• permits use of low-fluence

• particles are kept below the sublimation temperature

This technique

q

automatically compensates

y

p

for any changes in

y

g

the experimental conditions

• fluctuations in local ambient temperature

• variation in laser fluence

• laser beam attenuation by the particulate matter

• desorption of condensed volatile material

(14)

What Do We N e e d t o K now in

Adva nc e ?

calibration source

• radiance or irradiance calibration

electronics

• relative photodetector sensitivity

• photodetector gain

• amplifier gain

optics

• absolute neutral density filter transmission

y

• relative dichroic mirror reflectivity and interference filter

transmission

dimensions of probe volume

p

laser spatial fluence profile

(15)

AC-LI I I nst rum e nt Ca librat ion

Pulsed Nd:YAG Laser

Beam Shaping Optics Pulsed Nd:YAG Laser

Beam Shaping Optics Automatic Signal Attenuation 720 nm Detector Measurement Automatic Signal Attenuation 720 nm Detector Measurement Integrating Sphere Receiver Optics Detector 440 nm Measurement Location Receiver Optics Detector 440 nm Measurement Location 440 nm Detector 440 nm Detector

• integrating sphere with a traceable

spectral radiance calibration

• incandescence from black carbon

particles follows identical path as

calibration source

(16)

Pa r t icle Em ission I nt e nsit ie s

blackbody and soot

particle emission intensity

1e+13

• over range of

temperatures encountered

in LII over the UV-VIS-NIR

W m -3 st er -1 1e+11 1e+12 3500 K 4000 K 4500 K

spectral range

emissivity

In te ns ity, W 1e+9 1e+10 3000 K 3500 K

soot particles are

W l th

200 300 400 500 600 700 800 9001000 1e+8

1e+9

2500 K Solid lines: blackbody Dashed lines: soot particle

soot particles are

calculated for

d

_p

= 30 nm

and

E(m) = 0.4

(17)

Aut o-Com pe nsat ing LI I (AC-LI I )

Absolut e Signa ls

g

1.E+12 3500 3750 780 nm Intensity 400 nm Intensity 1.E+11 (W/m 3 *s r) 3000 3250 (K) Temperature 1.E+10 c tra l In ten s ity ( 2750 3000 Te m p er atur e 1.E+09 Sp e c 2250 2500

laminar diffusion flame, HAB = 42 mm laser = 1064 nm

1.E+08

0 200 400 600 800 1000 1200 1400 1600 1800

Time After Peak of Laser Pulse (ns)

2000 fluence = 1.06 mJ/mm2

(18)

LI I : Post -DPF Se nsit ivit y a nd Dyna m ic

Ra nge

g

• Post DPF (diesel

particulate filter) BC

0.008 0.010

particulate filter) BC

emissions from a

2007-compliant

heavy duty diesel

1 60 1.80 0.004 0.006 n tr a tion (mg/m 3)

heavy-duty diesel

engine operating on

the EPA FTP cycle

D

t t d

1.00 1.20 1.40 1.60 g /m 3 ) 0.000 0.002 150 160 170 180 190 200 Time (s) Co nc e n

• Demonstrated range,

sensitivity, and time

response of Artium LII

0 20 0.40 0.60 0.80 o n cen tratio n (m g Time (s)

300 instrument (<2

μg/m

3

_{at 20 Hz)}

-0.20 0.00 0.20 0 200 400 600 800 1000 1200 Time (s) C o Time (s)

(19)

Out line

Background

Laser-induced Incandescence (LII)

Laser induced Incandescence (LII)

High-Sensitivity Laser-induced Incandescence (HS-LII)

Comparison to other Instruments

p

Applications

Summary

(20)

Opt ic a l la yout of high se nsit ivit y

syst e m (H S-LI I )

syst e m (H S LI I )

Exhaust Line (Outlet)

Sample

AA

ir Flow

Sample Cell

Sample Lines (Inlet)

(21)

Ex pe rim e nt : H igh Se nsit ivit y LI I

• optimize all aspects of the autocompensating laser-induced

incandescence (AC-LII) method

• use Lagrangian invariant principle to constrain design of collection

use Lagrangian invariant principle to constrain design of collection

optics and receiver

(22)

Out line

Background

Laser-induced Incandescence (LII)

Laser induced Incandescence (LII)

High-Sensitivity Laser-induced Incandescence (HS-LII)

Comparison to other Instruments

p

Applications

Summary

(23)

T im e -re solve d H S-LI I a nd SP2

• HS-LII and SP2 compare well

- best agreement at concentrations below 2.0

μg/m

3

- SP2 can’t measure BC below about 70nm

b b

f

d h

f

hl

i

d

i l

(24)

T im e -re solve d H S-LI I a nd SP2

• HS-LII and SP2 compare well

- SP2 can’t measure BC below about 70nm

- SP2 shows less response at higher concentrations

ll

i l

h

i

l

hi h

?

(25)

T im e -re solve d H S-LI I a nd PA

) rat ion ( μ g/ m 3 ) M ass Concen tr BC M Date

(26)

At m osphe ric Bla ck Ca rbon: H S-LI I vs.

Phot oa c oust ic

5 4 3 m) -1 a) 35 30 25 20 m) -1 b) 2 1 0 -1 Δ Bab s (M 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 20 15 10 5 0 Δ Bsca t (M 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Particle mass loading (µg m-3)

Number of data points

72 158173 120 68 71 93 40 38 27 46 14 8 7

72 158 173 120 68 71 93 40 38 27 46 14 8 7

60

40

c)

• The variations of (a) the particle light absorption

(PA) (b)

ti l li ht

tt i

(PA)

d ( ) th

40 20 0 -20 Δ SV F ( 1 0 -9 ppm)

(PA), (b) particle light scattering (PA), and (c) the

soot volume fraction (LII), as a function of particle

volatile coating mass

• The photoacoustic results are significantly affected

-40 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

0 23 27 19 7 0 2 0 12 16 24 0 0 5

The photoacoustic results are significantly affected

by the presence of a volatile coating

• LII shows no significant effect

(27)

U se of Sim ult a ne ous LI I a nd PA t o

De t e r m ine Spe c ific Absor pt ion Coe ffic ie nt

40 35 30 1 ) Case 1 (e) Period 1 40 35 30 -1 ) Case 1 (f) Period 1 25 20 SAC ( m 2 g -1 + + + + + + + ₊ + - - ---- 25 20 S AC (m 2 g -+ + + + + + + + + - - --- _- -15 10 120 100 80 60 40 20 0 + Period 2 15 10 110 100 90 80 70 60 50 + Period 2

Non-refractory mass to BC mass ratio PPS (nm)

(28)

Out line

Background

Laser-induced Incandescence (LII)

Laser induced Incandescence (LII)

High-Sensitivity Laser-induced Incandescence (HS-LII)

Comparison to other Instruments

p

Applications

(29)

M obile Plat for m s

CRUISER

• 2 sonic anemometers

• 1 aircraft turbulence probe

• GPS, accelerometer, tilt-meter

• Aerosol Mass Spectrometer

• Single Particle Soot Photometer

(SP2)

• High Sensitivity Laser-Induced

Incandescence (HS-LII)

• PTR-MS

• CO2, CO, SO2, NO, NO2, Noy

l

b

• meteorology; webcam

• Fast Mobility Particle Sizer (FMPS)

• CPC

MAPLE

• Aerosol Time of Flight Mass spectrometer (ATOF-MS)

H

t d/

l d i l t

t

• Heated/cooled inlet system

• High-resolution Aerodyne Aerosol Mass Spectrometer

(HR-ToF-MS)

(30)

U rba n Air Qua lit y – H igh Se nsit ivit y

Laser-Induced Incandescence - Albert/Slater and Wurtemburg Park - 13 June 2007

6.0

CRUISER stationary

CRUISER mobile CRUISER mobile

4.0 5.0 a rt s per tri llion)

First phase mobile measurements recorded along Albert, Slater, Elgin, and Rideau streets.

Stationary measurements performed at Wurtemburg Park.

Second phase mobile measurements

3.0 n Conce n tr ation (p

a _{Second phase mobile measurements}

recorded along Rideau, Wellington, Lyon, Slater, Elgin, and Albert Streets.

1.0 2.0 B lac k C ar b o n 0.0 08:20 08:30 08:40 08:50 09:00 09:10 09:20 09:30 09:40 09:50 10:00 10:10 10:20 Time of Day

(31)

U rba n Air Qua lit y – H igh Se nsit ivit y

Laser-Induced Incandescence - 88 Albert Street - 13 June 2007

14.0 16.0

LII data - 10 Hz LII data - 1 Hz Average

10.0 12.0 o n ( µ g/ m 3 ) 6.0 8.0 a rbon Conc entra ti o 2 0 4.0 B la ck C 0.0 2.0 07:56 07:57 07:58 07:59 08:00 08:01 08:02 08:03 08:04 08:05 08:06 08:07 08:08 Time of Day

(32)

One M ont h of H S-LI I BC Dat a

• 30 days

• 2 Hz

• 5,000,000

individual

measurements

(33)

H e avy Dut y Die se l vs. Ga soline

Ve hicle s

• SP2/LII ratio is highest during periods when there is an increase

in HDD; lowest during rush hours (LDGV)

(34)

BC from Ga soline Ve hicle s is

U nde re st im at e d

FEVER study

~9X higher

(35)

Out line

Background

Laser-induced Incandescence (LII)

Laser induced Incandescence (LII)

High-Sensitivity Laser-induced Incandescence (HS-LII)

Comparison to other Instruments

p

Applications

(36)

Sum m a r y

Laser-induced incandescence

• technique with high specificity to the measurement of black carbon

• HS LII has the sensitivity to measure atmospheric levels of BC

• HS-LII has the sensitivity to measure atmospheric levels of BC

The combination of LII with other techniques used to measure BC

provides additional and valuable insights

• LII+PA to determine specific absorption coefficient

• LII+SP2 to assess the source of BC emissions (gasoline vs. diesel)

Example insights

• the specific absorption coefficient, which is the ability of BC to absorb

solar radiation and affects the impact of BC on climate change is greatly

solar radiation and affects the impact of BC on climate change, is greatly

enhanced by the degree of volatile coating on the surface of the BC

particles

• results suggest that

greater attention must be paid to black carbon

from gasoline engines

to obtain a full understanding of the impact of

from gasoline engines

to obtain a full understanding of the impact of

black carbon on air quality and climate and to devise appropriate

mitigation strategies

(37)

Que st ions?

John Liggio, Mark Gordon, Jeffrey R.

Brook, Gregory Smallwood, Shao-Meng Li,

Craig Stroud Ralf Staebler Gang Lu

Craig Stroud, Ralf Staebler, Gang Lu,

Patrick Lee, Brett Taylor, (2012). “Are

emissions of black carbon from gasoline

vehicles underestimated? Insights from

near and on-road measurements ”

near and on road measurements,

Environmental Science and Technology,

46, 4819-4828, 2012.

(38)

Soot Conc e nt rat ion from T w o-Color

Pyrom e t r y

temperature

is determined from the spectral radiance

signals at two wavelengths

• varies with

relative

E(m)

at the two wavelengths

soot volume fraction

is determined from the temperature

and the spectral radiance signal at either one of the

wavelengths

• depends upon

p

absolute value of

E(m)

( )

at the selected