techniques for determining psd of pm: laser diffraction vs. electrical sensing zone a 242 nd acs...
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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
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)
Optical Method for PSD Analysis: Optical Method for PSD Analysis:
(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)
Optical Method for PSD Analysis: Optical Method for PSD Analysis:
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)
Materials & MethodsMaterials & Methods
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
Materials & MethodsMaterials & Methods
NCSULS13 320
UIUCLA-300
TAMUCCM3
PM Samples
USDA
CCM3 LS230
Materials & MethodsMaterials & Methods
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
Materials & MethodsMaterials & Methods
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
Results & DiscussionResults & Discussion
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
Results & DiscussionResults & Discussion
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
Results & DiscussionResults & Discussion
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
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
Results & DiscussionResults & Discussion
Results & DiscussionResults & Discussion
Results & DiscussionResults & Discussion
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
Results & DiscussionResults & Discussion
LS13 320LS13 320
N=52 (26 for Winter, 26 for Spring)N=52 (26 for Winter, 26 for Spring)
Results & DiscussionResults & Discussion
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)
Measured mass Measured mass
fraction (%) fraction (%) Lognormal mass Lognormal mass
fraction (%) fraction (%) Relative Relative
difference (%)difference (%)
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
Results & DiscussionResults & Discussion
LA-300LA-300
N=52 (26 for Winter, 26 for Spring)N=52 (26 for Winter, 26 for Spring)
Results & DiscussionResults & Discussion
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)
Measured mass Measured mass
fraction (%) fraction (%) Lognormal mass Lognormal mass
fraction (%) fraction (%) Relative Relative
difference (%)difference (%)
PMPM1010 41.75±3.7441.75±3.74 40.76±4.1940.76±4.19 2.46±2.062.46±2.06
Results & DiscussionResults & Discussion
N= 26 for WinterN= 26 for Winter
CCM3CCM3
Results & DiscussionResults & Discussion
TAMU-CCM3TAMU-CCM3(N=26)(N=26)
PMPM1010 and PM and PM2.52.5 Mass Fraction Analyses (USDA) Mass Fraction Analyses (USDA)
Measured mass Measured mass
fraction (%) fraction (%) Lognormal mass Lognormal mass
fraction (%) fraction (%) Relative Relative
difference (%)difference (%)
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
Results & DiscussionResults & Discussion
LS230LS230
CCM3CCM3
N= 26 for SpringN= 26 for Spring
Results & DiscussionResults & Discussion
N=26 for SpringN=26 for Spring
LS230LS230
PM10
PM2.5
Results & DiscussionResults & Discussion
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