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Peak exposures in aluminium potrooms: instrument development and field calibration.

Authors
Carter-SR; Seixas-NS; Thompson-ML; Yost-MG
Source
J Environ Monit 2004 Nov; 6(11):932-937
NIOSHTIC No.
20029011
Abstract
Aluminium smelter potrooms are unique in that workplace exposures to hydrogen fluoride (HF), sulfur dioxide (SO2), and particulate matter occur simultaneously for some tasks. The peak exposures to these contaminants are of increasing interest in discovering the etiology of respiratory health effects. While a variety of direct-reading instruments are available for sulfur dioxide and particulate matter, only a few exist for hydrogen fluoride. The sensors in these HF instruments have a cross-sensitivity to sulfur dioxide making it difficult to monitor HF in an environment that also contains SO2. To overcome this problem, we assessed the simultaneous use of two electrochemical instruments: one with a SO2 sensor that does not respond to HF and the second with a hydrogen fluoride sensor that responds to both HF and SO2 in a 1 : 1 ratio, termed 'total acid gas'. The difference in the response between the two instruments should indicate the HF concentration: [HF + SO2] minus SO2 equals HF. The performance characteristics of this sampling train were evaluated in the laboratory through the generation of both HF and SO2 with permeation tubes. The response and recovery times for the SO2 only instrument were acceptable (6 and 15 s, respectively), but the "total acid gas" instrument exhibited both slow response and slow recovery approaching three and six min. The association between the traditional integrated filter sampling method and the direct-reading instrument for SO2 is 0.80 (Spearman's rho). The use of the digital filter strengthens the association between the HF direct-reading instrument and the integrated samples from 0.41 to 0.68.
Keywords
Gas-indicators; Gas-meters; Gas-sampling; Acid-gases; Hydrogen-ion-activity; Fluoride-compounds; Fluorides; Sampling; Sampling-equipment; Sampling-methods
Contact
Department of Occupational and Environmental Health Sciences, University of Washington, P.O. Box 357234, Seattle, WA 98195, USA
CODEN
JEMOFW
CAS No.
7664-39-3; 7446-09-5
Publication Date
20041101
Document Type
Journal Article
Email Address
srcarter@u.washington.edu
Funding Type
Grant
Fiscal Year
2005
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-003965
Issue of Publication
11
ISSN
1464-0325
Source Name
Journal of Environmental Monitoring
State
WA
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