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Glossary 

This glossary provides definitions of common terms used in the context of air pollution.

You can navigate quickly to a term using the alphabetic links below; clicking on the terms will show their definition.



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  • TEOM
    The tapered element oscillating microbalance (TEOM) is used to continuously measure particulate concentrations. It measures the mass collected on an exchangeable filter cartridge by monitoring the corresponding frequency changes of a tapered element. The sample flow passes through the filter, where particulate matter collects, and then continues through the hollow tapered element on its way to an electronic flow control system and vacuum pump. A principal concern with the TEOM instrument is that the filter is held at an elevated temperature (50°C) in order to minimise errors associated with the evaporation and condensation of water vapour. This can lead to the loss of the more volatile species and has led to the identification of differences between TEOM and gravimetric measurements at co-located sites. In the past, a factor of 1.3 was applied to all TEOM-measured concentrations to estimate the gravimetric equivalent. Now, the Volatile Correction Method (VCM) uses measurements of volatile particulate matter made by nearby FDMS instruments to correct TEOM measurements for the loss of such volatile material. The corrected measurements have been demonstrated to be equivalent to the gravimetric reference equivalent.
  • TOMPS
  • Trajectory Model

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Page last modified: 14 February 2011