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Aerosol Chemical Speciation Monitor (ACSM) Advances
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
Aerosol
SamplingIn from cyclone
Out to sampling pump
Filter
3-way Valve
Ng, et al., Aerosol Sci. Technol., 45:7, 770-784, 2011
No Sizing
9/8/2018 AMS Users Meeting 2016 2
Quadrupole, Q-ACSM Time-of-Flight, ToF-ACSM
9/8/2018 AMS Users Meeting 2016 3
Von der Weiden et al., Atmos. Meas. Tech., 2, 479-494, 2009.
Improved aerosol sampling system for efficient delivery of PM2.5 to aerodynamic lens
Intermediate Pressure Lens (IPL) delivers PM2.5 to detector
PM2.5 Capable ACSM – Laboratory CharacterizationXu et al., AS&T, 2016
9/8/2018 AMS Users Meeting 2016 4
Capture Vaporizer effectively vaporizes all large particles for complete detection of NR-PM2.5
PM2.5 Capable ACSM – Ambient CharacterizationZhang et al., ACPD, 2017
9/8/2018 AMS Users Meeting 2016 5
PM2.5 Capable ACSM – Ambient CharacterizationZhang et al., ACPD, 2017
9/8/2018 AMS Users Meeting 2016 6
Towards simplified calibration of ACSM - electrospray
Inlet (e.g., CPC)
Vacuum Pump
10 mCiPolonium Dryer/denuder
Needle Valve
AMS inletSyringe pump
Capillary
Grounded platewith orifice
sheath gas
Micro-positioner
static neutralizer
Capillary Grounded plate
Plastic cover
3025201510
50
AM
S O
rg d
M/d
log
10d
va (
µg
m-3
)3 4 5 6 7 8 9
1002 3 4 5 6 7 8 9
PToF Dva (nm)
30x109
2520151050
SM
PS
dV
/dlo
g10 d
M
3 4 5 6 7 8 9100
2 3 4 5 6 7 8 91000
SMPS Dm (nm)
15
10
5
0
15
10
5
0
20x109
15
10
5
0
15x109
10
5
0
1st Run
2nd Run
3rd Run
Dva = Dm * 0.91
Want repeatable (narrow) distribution to eliminate particle sizingWorked for oleic acid in acetonitrile but not for aqueous or saltsPractical concerns as well (e.g. radioactive source)
9/8/2018 AMS Users Meeting 2016 7
Towards new calibrations techniques – gas introduction
9/8/2018 AMS Users Meeting 2016 8
m/z
44
dif
f
CO2 Input / ppm
Slope = 1.37e-13
1e6*0.78*1.37e-13 amps/ppm = 1.06e-7 amps
Our airbeam signal is 1e-7 amps
Gases are easier to use for calibration than aerosols (by far).We get a nice calibration curve at varying CO2 concentrations.But what does this add?
Towards simplified calibration – Ultrasonic nebulizer and OPC
9/8/2018 AMS Users Meeting 2016 9
Generate particles with UN that are large enough to be counted by the OPCFeed ACSM and OPC the polydisperse and integrate the size distribution to calculate the input mass
Towards simplified calibration – Ultrasonic nebulizer and OPC
9/8/2018 AMS Users Meeting 2016 10
Towards simplified calibration – Ultrasonic nebulizer and OPC
9/8/2018 AMS Users Meeting 2016 11
UN/OPC Calibration Standard ACSM Calibration