ATOFMS instruments perform real-time measurements of ambient particles and have been used in a wide variety of environments, including on aircraft (ICE-L, CARES, CalNex) and oceanic research vessel platforms during international field campaigns (CalNex, INDOEX, ACE-Asia, CalCOFI). Measurements of particle composition and size made by ATOFMS provide valuable insights into aerosol transformation processes in both field studies and laboratory studies. Improvements to existing instruments and development of new instrumentation and data analysis methods are ongoing. Procedures for quantification of data and scaling detected ATOFMS particle types to atmospheric concentrations have been published. Comparison of source emission measurements to ambient data has permitted source apportionment of particle loadings. ATOFMS data has also been used as inputs to atmospheric chemistry models. Recently ATOFMS has seen increased use for the detection of bioaerosols. The ATOFMS has also been applied in characterizations of particles and particle concentrators used in aerosol health effects studies.
The ATOFMS development began in 1992 in the research laboratory of Prof. Kimberly Prather at the University of California at Riverside. Her research group moved in 2001 to the University of California at San Diego. Three generations of in-house ATOFMS instruments have been developed. The first generation (“The Beast”) is a stationary and single-polarity instrument used for lab studies and instrument development. The second generation instruments (“Jake” & “Elwood”) are field transportable, dual-polarity instruments and Jake is configured with an aerodynamic lens for detection of ultrafine particles (UF-ATOFMS) from 50-300 nm. The third generation ATOFMS (“Laverne”) is also field transportable and dual-polarity and was the prototype for TSI’s commercial ATOFMS instrument, Model 3800. The commercially available ATOFMS is now available with an optional aerodynamic lens for detection of particles from 30-300 nm (Model 3800-030). The ATOFMS User’s Group maintained by TSI is another valuable source of information and contains an extensive publications list of particle mass spectrometry. We are developing a chemical ionization ATOFMS ("Clifford"). The newest ATOFMS is an aircraft-ATOFMS ("Shirley") who is much smaller and fits on airplanes and perform faster measurements that allow us to probe mixed phase cloud chemistry. We are now able to determine the source of aerosols "on the fly" using a library of major sources developed in our group over the past 10 years.
