FAQ AMS Glossary

AMS glossary (beta)

Important Notes

This glossary of terms typically used by the AMS community is a work in progress - so is by no means complete or comprehensive. For now, we'll keep it alphabetical, but this may be changed based on user feed-back. Please continue to add and edit!

Glossary

AMS: Aerosol Mass Spectrometer

APES:

BBOA: Biomass Burning Organic Aerosol

Background:In general this term should be avoided as it is too ambiguous. (Background ambient measurement conditions? Background instrumental signal? etc.) The use of 'Closed mass spectra' is encouraged where appropriate.

Baseline: In a mass spectra, the 'region between the peaks' for an open, closed or difference mass spectra.

Closed: The mass spectrum taken with the chopper in the 'blocked' position, and typically considered instrument background and gas-phase contribution to AMS signal

CRiTTR

DAQ: Data Acquisition Software

Diff: The Difference Spectrum; difference in chopper-open mass spectrum and chopper-closed mass spectrum; typically considered the mass spectrum due to particle signal

f_44: the fraction of the organic signal that is observed at m/z = 44

fragments: a vaporized molecule is ionized in the AMS to a series of ions, which are then detected by either a quadrupole or time-of-flight mass spectrometer; the resulting ions are referred to as 'fragments'

HOA: Hydrocarbon-like Organic Aerosol

HR: High Resolution (as opposed to UMR, typically referring to either the High Resolution Time of Flight Aerosol Mass Spectrometer, or to the data derived from that instrument)

Light Scattering:

LV-OOA: Low volatility-oxidized organic aerosol

Non-refractory species: chemical components of aerosol that are volatilized in the AMS, and are observed in the "Difference spectrum". Examples include...

OOA: Oxidized Organic Aerosol

Open: Mass spectra acquired when the chopper is in the 'open' position - both air and aerosols are entering and being detected

PET: PMF Evaluation Tool. An interface for examining the results of many PMF analyses.

PIKA: Peak Integration by Peak Analysis. This is a somewhat contorted acronym, but this name really indicates "High Resolution Analysis" or HR analysis where individual peaks (C3H6 and C2H2O at ~ m/z 42).

PMF: Positive Matrix Factorization

Q: This has two uses. Q often refers to a quadropole AMS. But Q and Qexp are terms also used in a PMF analysis.

Refractory species: chemical components of aerosol that are not volatile enough to vaporize in the AMS, and thus are never observed by the instrument. Examples include black carbon (see SP2-AMS).

Semi-refractory signals: chemical components of aerosol that are relatively less volatile, and only slowly vaporize in the AMS. Functionally, they are observed in both the the Closed and Open signals (time-scale for vaporization is slow). Examples include Pb (lead) and possibly NaCl

SP2-AMS:

SPARROW: Single PARicle Retrieval Of Waves. The Igor analysis tool for AMS light scattering data.

SQUIRREL: SeQUential Igor data RetRiEvaL. The Igor analysis tool for non-Quad AMS data.

SV-OOA: Semi-Volatile Oxidized Organic Aerosol

ToF: Time of Flight mass spectrometer

UMR: Unit Mass Resolution (as opposed to HR: ie, signal observed at m/z 28 is UMR, whereas HR data typically shows two peaks, one from N2+ and another from CO+)