Chemical and microphysical characterization of ambient aerosols with the aerodyne aerosol mass spectrometer

Abstract

The application of mass spectrometric techniques to the real-time measurement and characterization of aerosols represents a significant advance in the field of atmospheric science. This review focuses on the aerosol mass spectrometer (AMS), an instrument designed and developed at Aerodyne Research, Inc. (ARI) that is the most widely used thermal vaporization AMS. The AMS uses aerodynamic lens inlet technology together with thermal vaporization and electron-impact mass spectrometry to measure the real-time non-refractory (NR) chemical speciation and mass loading as a function of particle size of fine aerosol particles with aerodynamic diameters between approximately 50 and 1,000 nm. The original AMS utilizes a quadrupole mass spectrometer (Q) with electron impact (EI) ionization and produces ensemble average data of particle properties. Later versions employ time-of-flight (ToF) mass spectrometers and can produce full mass spectral data for single particles. This manuscript presents a detailed discussion of the strengths and limitations of the AMS measurement approach and reviews how the measurements are used to characterize particle properties. Results from selected laboratory experiments and field measurement campaigns are also presented to highlight the different applications of this instrument. Recent instrumental developments, such as the incorporation of softer ionization techniques (vacuum ultraviolet (VUV) photo-ionization, Li+ ion, and electron attachment) and high-resolution ToF mass spectrometers, that yield more detailed information about the organic aerosol component are also described.

PM1 Chemical Characterization during the ACU15 Campaign, South of Mexico City

“…The ACSM data were analyzed for the mass concentrations and composition with the standard ACSM data analysis software written in Igor Pro (WaveMetrics Inc., Tigard, OR, USA). A collection efficiency (CE) of 0.5 was assumed to account for detection losses due to bounce of particles off the vaporizer [23]. This value was chosen in accordance to previous studies in Mexico City using other AMSs [13,18].…”

Rapid Aqueous-Phase Photooxidation of Dimers in the α-Pinene Secondary Organic Aerosol

“…AMS employs heating and electron impact (EI) ionization which result in significant fragmentation of organic molecules. 5 Most peaks in the AMS spectra represent a fragment arising from numerous organic species, and the AMS PMF analysis indicates the mass fraction of the fragment attributable to each extracted factor. On the other hand, CIMS is a soft ionization technique, and each CIMS peak likely represents an individual species and its structural isomers.…”

SOA Formation Potential of Emissions from Soil and Leaf Litter

“…38,39 The AMS was operated using v/w-mode switching with 30 s per save for each mode. An ionization efficiency calibration was performed the day prior to the experiment using the brute force single particle technique with 400 nm ammonium nitrate particles.…”