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Ambient air particulate matter: quantifying errors in gravimetric measurements.

Brown, A S; Yardley, R E; Quincey, P G; Butterfield, D M (2005) Ambient air particulate matter: quantifying errors in gravimetric measurements. NPL Report. DQL-AS 015

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This report details the results of a series of studies undertaken in order to improve filter gravimetry techniques and maximise the validity of a forthcoming UK-wide series of equivalence trials for particulate monitors.
The initial objectives of the study were to produce an optimised weighing protocol and to define the characteristics of the balances used, thus quantifying the major sources of error in the gravimetric technique. A further aim was to produce an uncertainty budget for the process.
Once established, the weighing protocol was used in investigations to select the filter material most suitable for ambient PM measurements. The effects of temperature and humidity; storage and transport; and inter-laboratory weighings on the mass of a variety of filter materials were studied.
It was found that the most important factors to consider when selecting a filter medium are variation of filter mass with temperature and relative humidity; structural integrity; flow resistance; chemical effects; particle sampling efficiency and static charge effects. Thorough consideration of these factors led to the selection of Emfab (PTFE-bonded glass fibre)
The project was funded by The Department for Environment Food and Rural Affairs (Defra) through Casella Stanger. The gravimetry facilities used at NPL were installed, commissioned and maintained with funding from the Department of Trade and Industry’s Valid Analytical Measurement Programme (a Programme within the DTI’s National Measurement System).

Item Type: Report/Guide (NPL Report)
NPL Report No.: DQL-AS 015
Keywords: uncertainty
Subjects: Environmental Measurement
Environmental Measurement > Air Quality and Airborne Particulates
Last Modified: 02 Feb 2018 13:16
URI: http://eprintspublications.npl.co.uk/id/eprint/3117

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