Techniques for Determining PSD of PM: Laser Diffraction vs. Electrical Sensing Zone A 242 nd ACS...

$: Techniques for Determining PSD of PM: Laser Diffraction vs. Electrical Sensing Zone A 242 nd ACS National Meeting Presentation: Paper ID18440 Z. Cao 1,$
Techniques for Determining PSD of PM: Laser Techniques for Determining PSD of PM: Laser

Diffraction Diffraction vsvs. Electrical Sensing Zone. Electrical Sensing Zone

A 242A 242ndnd ACS National Meeting Presentation: Paper ID18440 ACS National Meeting Presentation: Paper ID18440

Z. CaoZ. Cao11, M. Buser, M. Buser22, D. Whitelock, D. Whitelock33, L. Wang-Li*, L. Wang-Li*11, Y. Zhang, Y. Zhang44, C.B. , C.B.

ParnellParnell55

11NCSU, NCSU, 22OSU, OSU, 33USDA-ARS, USDA-ARS, 44UIUC, UIUC, 55TAMUTAMU

Introduction:Introduction:

• PM – NAAQS: PMPM – NAAQS: PM1010 & PM & PM2.52.5

• Health effects, Source identification/estimation, Health effects, Source identification/estimation,

Mitigation strategies – PM characteristics:Mitigation strategies – PM characteristics:

Physical propertiesPhysical properties

Mass, or number concentrations Mass, or number concentrations

Particle size distribution (PSD)Particle size distribution (PSD)

Morphology Morphology

Density, etc. Density, etc.

Chemical compositionsChemical compositions

Biological propertiesBiological properties

Introduction:Introduction:

• Various techniques for PSD measurement (analysis)Various techniques for PSD measurement (analysis)

Aerodynamic method (APS, Impactors, etc)Aerodynamic method (APS, Impactors, etc)

Optical method (optical counters, light scattering Optical method (optical counters, light scattering analyzers, etc) analyzers, etc)

Electrical sensing zone method (Coulter Counter)Electrical sensing zone method (Coulter Counter)

Electrical mobility and condensation method Electrical mobility and condensation method (DMA+CNC)(DMA+CNC)

Electron microscopyElectron microscopy

• No single agreed upon method – for different sourcesNo single agreed upon method – for different sources

Aerodynamic Particle Sizer (APS)Aerodynamic Particle Sizer (APS)

• Aerosol entering the tube is assumed to be uniformAerosol entering the tube is assumed to be uniform

• Dilution system - reduce problems with particle Dilution system - reduce problems with particle coincidence in the sensorcoincidence in the sensor

• Light scattered - changes rapidly with dLight scattered - changes rapidly with dpp::

small particle processor : AED 0.5 – 15.9 small particle processor : AED 0.5 – 15.9 mm

large particle processor: AED 5 – 30 large particle processor: AED 5 – 30 mm

• Monodisperse latex spheres are used for Monodisperse latex spheres are used for calibration of full size range of the APScalibration of full size range of the APS

• Not work for PSD on sampler filterNot work for PSD on sampler filter

• Field real-time measurementField real-time measurementCh5.8: pages 136-138 of Hinds

Aerodynamic Method for PSD Analysis:Aerodynamic Method for PSD Analysis:

ImpactorsImpactors

Aerodynamic Method for PSD Analysis:Aerodynamic Method for PSD Analysis:

• On-site measurements in mass On-site measurements in mass concentration and PSDconcentration and PSD

• Limited size rangesLimited size ranges

• Particle bounceParticle bounce

• Particle lossesParticle losses

Optical Particle Counters Optical Particle Counters

Optical Method for PSD Analysis: Optical Method for PSD Analysis:

http://www.particlecounters.org/optical/

• Detect and counts one particle at a timeDetect and counts one particle at a time

• Calibration?Calibration?

•High level PM environment?High level PM environment?

http://en.wikipedia.org/wiki/Particle_counter

http://en.wikipedia.org/wiki/File:Particlecounter.jpg

LS13 320 Multi-wave Length Laser Diffraction LS13 320 Multi-wave Length Laser Diffraction Particle Size Analyzer (0.04 – 2000 Particle Size Analyzer (0.04 – 2000 m)m)

Rayleigh Scattering TheoryRayleigh Scattering Theory

Mie Scattering theoryMie Scattering theory

Polarization Intensity Differential Scattering (PIDS)


(Source: Beckman Coulter, Miami, FL)(Source: Beckman Coulter, Miami, FL)

Fraunhofer Diffraction and LA-300 (Source: Horiba Instrument Inc, Irvine, CA)Fraunhofer Diffraction and LA-300 (Source: Horiba Instrument Inc, Irvine, CA)


LA-300 Laser Scattering Particle Size AnalyzerLA-300 Laser Scattering Particle Size Analyzer

Electrical Sensing Zone Method for PSD Analysis:Electrical Sensing Zone Method for PSD Analysis:

Source: Beckman Coulter, Miami, FLSource: Beckman Coulter, Miami, FL

• Only suitable for insoluble Only suitable for insoluble

particlesparticles

• Not an onsite measurementNot an onsite measurement

•Ultrasonic bath – all particles are Ultrasonic bath – all particles are

fully dispersed in the liquid fully dispersed in the liquid

solution (PM on filter) solution (PM on filter)

•Size calibrated with polystyrene Size calibrated with polystyrene

spheres of known sizespheres of known size

• Counting rate – 3000 particles/sCounting rate – 3000 particles/s

Coulter Counter MultisizerCoulter Counter Multisizer

• Current through the orificeCurrent through the orifice

• Particle electrical resistance ~ dParticle electrical resistance ~ dpp

• Change in current ~ dChange in current ~ dpp

Differential Mobility AnalyzerDifferential Mobility Analyzer

(DMA)(DMA)• Used as a monodisper aerosol generator to Used as a monodisper aerosol generator to

produce sub-micrometer-sized aerosols for produce sub-micrometer-sized aerosols for testing and calibrationtesting and calibration

• Measure PSD in the sub-micrometer size Measure PSD in the sub-micrometer size rangerange

• Particles with greater mobility migrate to the Particles with greater mobility migrate to the center rodcenter rod

• Exiting aerosol – slightly charged and nearly Exiting aerosol – slightly charged and nearly monodisperse –size controlled by the voltage monodisperse –size controlled by the voltage on the central rodon the central rod

• 0.005 – 1.0 0.005 – 1.0 mm

Ch15.9 of Hinds

Electrical Mobility Method for PSD Analysis:Electrical Mobility Method for PSD Analysis:

Condensation Nucleus Counter (CNC)Condensation Nucleus Counter (CNC)

Fly-ash Fly-ash Corn StarchCorn Starch

Electron Microscopy Method for PSD Analysis:Electron Microscopy Method for PSD Analysis:

Electron Scanning Microscopy (ESM) Electron Scanning Microscopy (ESM)

• Differences in PSD measurements for PM with Differences in PSD measurements for PM with

MMDs in micrometers (agricultural sources)MMDs in micrometers (agricultural sources)

Light scattering methodLight scattering method

Electrical sensing zone methodElectrical sensing zone method

• PM sample typesPM sample types

• Filter-based PM samples with MMD>>10 Filter-based PM samples with MMD>>10 mm

• Testing aerosols with MMD ~ 10 Testing aerosols with MMD ~ 10 mm

Objectives:Objectives:

PSD AnalyzersPSD Analyzers

LS13 320 multi-wave length laser diffraction LS13 320 multi-wave length laser diffraction particle size analyzer - particle size analyzer - NCSUNCSU

LA-300 laser scattering particle size analyzer – LA-300 laser scattering particle size analyzer – UIUCUIUC

Coulter Counter Multisizer3 – Coulter Counter Multisizer3 – TAMUTAMU

Coulter Counter Multisizer3 – Coulter Counter Multisizer3 – USDA USDA

LS230 laser diffraction particle size analyzer – LS230 laser diffraction particle size analyzer – USDA USDA

Materials & MethodsMaterials & Methods

(a) (b)

(c) (d)


PM Field Sampling – Low-volume TSP SamplersPM Field Sampling – Low-volume TSP Samplers

High-rise Layer HouseHigh-rise Layer House

• Field PM samples: filter-basedField PM samples: filter-based

26 samples/season for two seasons: distributed to the 26 samples/season for two seasons: distributed to the

three locationsthree locations

Analyzed under the same operation procedureAnalyzed under the same operation procedure

• Testing materials: not filter-based aerosolsTesting materials: not filter-based aerosols

LimestoneLimestone

StarchStarch

No.3 Micro AluminumNo.3 Micro Aluminum

No.5 Micro AluminumNo.5 Micro Aluminum


NCSULS13 320

UIUCLA-300

TAMUCCM3

PM Samples

USDA

CCM3 LS230


PM Sample Assignment/DistributionPM Sample Assignment/Distribution

Winter PM samplesWinter PM samplesSpring PM samplesSpring PM samples

Testing aerosolsTesting aerosolsWinter PM samplesWinter PM samples Spring PM samplesSpring PM samples

Testing aerosolsTesting aerosols

• PMPM1010 and PM and PM2.52.5 mass fraction analyses mass fraction analyses

Measured by the analyzerMeasured by the analyzer

Calculated using the lognormal distribution equationCalculated using the lognormal distribution equation

Checked for agreements (Relative Difference, %)Checked for agreements (Relative Difference, %)

Measured = PMMeasured = PM1010 or PM or PM2.52.5 measured by the analyzer measured by the analyzer

Lognormal = PMLognormal = PM1010 or PM or PM2.5 2.5 calculated using the lognormal calculated using the lognormal

distribution equationdistribution equation

Measured LognormalRD 100%

Measured


Results & DiscussionResults & Discussion

Measured MMDs (Measured MMDs (m) for Winter Samples: N=26m) for Winter Samples: N=26

LS13 320LS13 320 LA-300LA-300 CCM3CCM3

17.13±0.8117.13±0.81 22.71±1.4322.71±1.43 13.94±1.0013.94±1.00


Measured GSDs for Winter Samples: N=26Measured GSDs for Winter Samples: N=26

LS13 320LS13 320 LA-300LA-300 CCM3CCM32.63±0.042.63±0.04 2.02±0.112.02±0.11 1.85±0.041.85±0.04


Measured MMDs (Measured MMDs (m) for Spring Samples: N=26m) for Spring Samples: N=26

LS13 320LS13 320 LA-300LA-300 LS230LS230 CCM3CCM318.44±1.4418.44±1.44 22.62±2.6822.62±2.68 18.47±1.3818.47±1.38 13.99±0.7413.99±0.74


Measured GSDs for Spring Samples: N=26Measured GSDs for Spring Samples: N=26

LS13 320LS13 320 LA-300LA-300 LS230LS230 CCM3CCM32.67±0.112.67±0.11 1.99±0.151.99±0.15 2.65±0.222.65±0.22 1.84±0.041.84±0.04

Measured PSDs of Testing AerosolsMeasured PSDs of Testing Aerosols

LS13 320LS13 320 LA-300LA-300 LS230LS230 CCM3CCM3

Testing aerosols Testing aerosols MMD MMD (µm)(µm) GSDGSD

MMD MMD (µm)(µm) GSDGSD



LimestoneLimestone 7.507.50 3.073.07 12.2912.29 1.831.83 8.118.11 3.153.15 8.568.56 1.721.72

StarchStarch 13.3113.31 1.591.59 16.7816.78 1.501.50 14.3814.38 1.551.55 14.3214.32 1.331.33

#3 Micro aluminum#3 Micro aluminum 5.285.28 1.981.98 7.627.62 1.561.56 5.375.37 1.931.93 5.035.03 1.421.42

#5 Micro aluminum#5 Micro aluminum 7.097.09 1.691.69 8.388.38 1.491.49 7.217.21 1.711.71 6.316.31 1.391.39


PMPM1010 and PM and PM2.52.5 Mass Fraction Analyses (NCSU) Mass Fraction Analyses (NCSU)

Measured mass Measured mass

fraction (%) fraction (%) Lognormal mass Lognormal mass

fraction (%) fraction (%) Relative Relative

difference (%)difference (%)

PMPM1010 36.16±2.7336.16±2.73 34.92±2.7134.92±2.71 3.44±0.853.44±0.85

PMPM2.52.5 8.40±0.618.40±0.61 3.56±0.663.56±0.66 57.9±5.3757.9±5.37


LS13 320LS13 320

N=52 (26 for Winter, 26 for Spring)N=52 (26 for Winter, 26 for Spring)


N=52 N=52

26 for Winter 26 for Winter

26 for Spring)26 for Spring)

LS13 320LS13 320

PM10

PM2.5

PMPM1010 and PM and PM2.52.5 Mass Fraction Analyses (UIUC) Mass Fraction Analyses (UIUC)





PMPM1010 20.60±2.5320.60±2.53 19.88±2.5619.88±2.56 3.34±5.343.34±5.34

PMPM2.52.5 4.57±0.644.57±0.64 0.25±0.140.25±0.14 94.46±3.0594.46±3.05


LA-300LA-300

N=52 (26 for Winter, 26 for Spring)N=52 (26 for Winter, 26 for Spring)


N=52 N=52

26 for Winter 26 for Winter

26 for Spring26 for Spring

LA-300LA-300

PM10

PM2.5

PMPM1010 Mass Fraction Analyses (TAMU) Mass Fraction Analyses (TAMU)





PMPM1010 41.75±3.7441.75±3.74 40.76±4.1940.76±4.19 2.46±2.062.46±2.06


N= 26 for WinterN= 26 for Winter

CCM3CCM3


TAMU-CCM3TAMU-CCM3(N=26)(N=26)

PMPM1010 and PM and PM2.52.5 Mass Fraction Analyses (USDA) Mass Fraction Analyses (USDA)





PMPM1010 33.71±3.2933.71±3.29 33.39±2.9933.39±2.99 0.79±4.450.79±4.45

PMPM2.52.5 8.18±0.968.18±0.96 3.28±1.063.28±1.06 60.44±11.5360.44±11.53

PMPM1010 41.11±3.6841.11±3.68 40.93±3.5040.93±3.50 0.39±0.800.39±0.80

PMPM2.52.5 1.43±0.351.43±0.35 0.65±0.260.65±0.26 54.96±13.0454.96±13.04


LS230LS230

CCM3CCM3

N= 26 for SpringN= 26 for Spring


N=26 for SpringN=26 for Spring

LS230LS230

PM10

PM2.5


N=26 for SpringN=26 for Spring

CCM3CCM3

PM10

PM2.5

ConclusionsConclusions

• Different analyzers: significant differences in MMDs and Different analyzers: significant differences in MMDs and

GSDs for filter-based samples GSDs for filter-based samples

LA-300: the largest MMDs; CCM3: the smallest MMDLA-300: the largest MMDs; CCM3: the smallest MMD

LS13 320: the largest GSDs; CCM3: the smallestLS13 320: the largest GSDs; CCM3: the smallest

• The PSD results of testing aerosols - consistent with that of The PSD results of testing aerosols - consistent with that of

filter-based samplesfilter-based samples

LA-300: large MMDs LA-300: large MMDs

LS13 320 & LS230: large GSDLS13 320 & LS230: large GSD

• PSDs measured by LS13 320 & LS230 agreed well PSDs measured by LS13 320 & LS230 agreed well

ConclusionsConclusions

• All RDs in PMAll RDs in PM1010 mass fractions of the measured and mass fractions of the measured and

the fitting values < 5%, which is acceptablethe fitting values < 5%, which is acceptable

• All RDs in PMAll RDs in PM2.5 2.5 mass fractions of the measured and mass fractions of the measured and

the fitting values >> 5%, which is not acceptable. the fitting values >> 5%, which is not acceptable.

AcknowledgementAcknowledgement

• The USDA NRI Grant No. 2008-35112-18757 The USDA NRI Grant No. 2008-35112-18757

• Help from Qianfeng Li & Zifei Liu for field Help from Qianfeng Li & Zifei Liu for field

sampling sampling

• Support from the egg production farmSupport from the egg production farm

Techniques for Determining PSD of PM: Laser Diffraction vs. Electrical Sensing Zone A 242 nd ACS...

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