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Environmental Health Criteria 214

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HUMAN EXPOSURE ASSESSMENT<br />

by analytical instruments, such as spectrophotometry, gas<br />

chromatography with specific or non-specific detectors, HPLC, etc.<br />

Although not yet used extensively, small, evacuated canister samplers<br />

have been developed for personal monitoring (Pleil & Lindstrom, 1995).<br />

These have the advantage of not using sorbents. Analysis is typically<br />

done by gas chromatography following thermal desorption.<br />

7.2.1.3 Direct-reading instruments<br />

The concentration of gases and vapours (e.g., carbon monoxide,<br />

sulfur dioxide) in an individual's breathing zone can also be<br />

determined with the use of portable direct-reading instruments.<br />

Commercially available direct-reading instruments have data logging<br />

capabilities to store measurements at a rate of 1 s -1 . Depending on<br />

the frequency of measurements, these instruments can operate up to<br />

2 weeks continuously. Instrument software allows for direct<br />

calculation of concentrations with different averaging times and<br />

statistical analysis of the data.<br />

Table 21. Air sampling methods for inorganic gases<br />

Carbon monoxide Manufacturer Comments<br />

Continuous<br />

Electrochemical Energetic Sciences 0-50, 0-100 ppm; portable and<br />

LOD ~ 2 ppm<br />

Interscan Various ranges; LOD ~ 1 ppm<br />

Bacharah Based on the measurement of Hg<br />

from a pellet oxidized by CO.<br />

0-20 dl: 1 ppm Sample flowrate<br />

litre/min<br />

Photometers Beckman Instruments Based on dual-isotope fluoresc<br />

LOD = 0.1 ppm<br />

Passive<br />

Diffusion detectors Lab Safety Supply Co. Changes colour; LOD ~ 50 ppm f<br />

Quantum Group Inc. Simple colour change detector<br />

3M Corporation Indicates presence of CO by co<br />

change<br />

Wilson Safety Products Dosimeter badge. Colour change<br />

proportional to CO concentrati<br />

Active MSA Air is pumped through activate<br />

tubes that change colour when<br />

Table 21. (continued)<br />

Sensidyne<br />

http://www.inchem.org/documents/ehc/ehc/ehc<strong>214</strong>.htm<br />

Page 114 of 284<br />

6/1/2007

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