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ACSM Update
Phil Croteau
August 24, 2019 AMS Users Meeting – Lund 1
Aerosol Chemical Speciation Monitor (ACSM)
Thermal Vaporization &
Electron Impact
Ionization
Aerodynamic lens
Particle Beam Generation
Particle Composition
Data AcquisitionComputer
TOF
or
Q-M
S
Turbo Pumps
AerosolSamplingIn from
cyclone
Out to sampling pump
Filter
3-way Valve
Ng, et al., Aerosol Sci. Technol., 45:7, 770-784, 2011
AMS Users Meeting – Lund August 24, 2019 2
No Size
Quadrupole, Q-ACSM Time-of-Flight, ToF-ACSM
AMS Users Meeting – Lund August 24, 2019 3
Von der Weiden et al., Atmos. Meas. Tech., 2, 479-494, 2009.
3/24/2019 CIAAS 2019 4
Aerosol
Sampling
Particle Beam
Generation
Particle
Composition
PM2.5 Capable ACSM Development and Lab EvaluationXu et al., Aerosol Sci. Technol., 51:1, 69-83, 2017 DOI:10.1080/02786826.2016.1241859
PM2.5 ACSM Inlet Hardware
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ACSM Calibration Project Overall goal – Simplify and decrease cost of ACSM calibration
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ACSMDMA
CPC
Atomizer
Aerosol
Diluter
By-pass
filter
Drier
Mixing Tube
Very Important!!
Results – Calibration
• Evaluated several approaches to calibration – landed on ultrasonic nebulization of NH4NO3 and integrating OPC measured size distribution to calculate mass for further development
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Results – CalibrationStandard ACSM CalibrationUN/OPC ACSM Calibration
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Since last time – Maybe we can do what we’ve always done but with lower cost components
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Low resolution radial
ACSMDMA
CPC
Atomizer
Aerosol
Diluter
By-pass
filter
Drier
Mixing Tube
Small, water-based
3D Printed
3D Printed atomizer – collaboration with Daniel Cziczoand Michael Rösch (MIT)
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Particle size selection – Spider DMAStavros Amanatidis (CalTech) and Susanne Hering (ADI)
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Particle Counting – MAGIC CPC
August 24, 2019 AMS Users Meeting – Lund 12
Testing MAGIC as aerosol source and Spider as counter
AtomizerBipolarIons (Kr)
TSI Long DMA +3776 CPC
R=10, 3.9/0.39
TSI Long DMA +3776 CPC
R=4.4, 3.9/0.89
Magic SpiderR=4.1, 1.1/.26
AMS
300 nm at 5 concentrations 300 nm, no ions189 nm at 1 concentration (Spider only)122 nm “
81 nm “55 nm “August 24, 2019 AMS Users Meeting – Lund 13
AMS measured PTOF size distributions of Dmob = 300nm particles from TSI and Spider DMA. Roughly normalized.
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ACSM Calibration comparing Spider DMA and TSI DMA
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Vertically mounted ACSM – Wade Robinson
• 19” Rack mounted design• Standardize PM2.5 inlet sampling
plumbing• Better for integration into
monitoring stations
August 24, 2019 AMS Users Meeting – Lund 16
Q-ACSM – Pfeiffer will stop producing PrismaPlus and move to new PrismaPro
• Expect similar performance
• More analog and digital I/O
• Communication standard different• Requires significant rewrite
of ACSM DAQ
August 24, 2019 AMS Users Meeting – Lund 17
TOF-ACSM X – almost exists
• TOF-ACSM with a higher resolution mass spectrometer (res ~>2000)• Same body as HTOF but with same dynode detector used in TOF-ACSM
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