Aerosol Time-of-Flight Mass Spectrometry

ATOFMS instruments perform real-time measurements of aerodynamic diameter and chemical composition of ambient particles.

Brief Development Timeline:
1st generation (1992): “The Beast” is a stationary laboratory single-polarity instrument used for instrument development. The Beast currently resides with former Prather group member Prof. Ryan Moffet at University of the Pacific
2nd generation (1997) "Jake" and "Elwood" are field transportable, dual-polarity instruments. Jake is configured with an aerodynamic lens for detection of ultrafine particles (UF-ATOFMS) from 80-1000 nm. 
3rd generation (1999) “Laverne” is also field transportable and dual-polarity and was the prototype for TSI’s commercial ATOFMS instrument, (Model 3800) and with aerodynamic lens for detection of particles from 30-1000 nm (Model 3800-030). 
4th generation (2005) "Shirley" is an aircraft-ATOFMS that incorporates improvements in size and peformance that allow us to probe the particles seeding mixed phase clouds. Shirley has flown on the DOE G1 and NCAR C130.  

A chemical ionization version of the ATOFMS ("Clifford") is currently under development.

Just a few studies that ATOFMS has been a part of:
ICE-L, CARES, CalNex, PRADACS 2010-2011, CalWater 2011, INDOEX, ACE-Asia, CalCOFI, CARES, IMPACTS, FIN1, CalWater 2015

Ongoing instrument development  and data analysis projects:
Procedures for quantification and scaling detected ATOFMS particle types to atmospheric concentrations 
Source apportionment of ambient particles, i.e. comparison of emission mass spectral "fingerprints" to atmospheric particle measurements 
Data from ATOFMS are being used as inputs to improve atmospheric chemistry and climate models 
Detection of bioaerosols by ATOFMS has been performed for the and health effects studies

Elwood










ATOFMS
Born: 1996 - Riverside, California
Inlet: Converging Nozzle
Size Range: 0.2 - 3 micrometers
Ion Polarity: Positive and Negative
LDI Laser: Quantel 266 nm, 20 Hz (Nd:YAG)
Named after: Elwood Blue of the Blues Brothers

Prototype for the TSI 3800



Jake










Born: 1996 Riverside, CA
Description: Ultrafine (UF) ATOFMS
Inlet: Aerodynamic Focusing Lens
Size Range: 50 nm - 1000 nm
Polarity: Positive and Negative
Laser: Quantel 266 nm, 20 Hz (Nd:YAG)
Named after: Jake Blue of the Blues Brothers
Prototype for TSI 3800 (with Elwood); modified in 2002 to use Aerodynamic Lens inlet (formerly converging nozzle)

Laverne










ATOFMS
Description: ATOFMS
Inlet: Converging Nozzle
Size Range: 0.2 - 3 micrometers
Polarity: Positive and Negative
Laser: Quantel 266 nm, 20 Hz (Nd:YAG)

Shirley










Aircraft Aerosol Time of Flight Mass Spectrometer (A-ATOFMS)
Born: 2005; San Diego, CA
Inlet: Aerodynamic Lens
Size Range: 70 nm - 1200 nm
Polarity: Positive and Negative (z-shape)
Laser: Big Sky/Quantel, 50 Hz, Nd:YAG