Environmental versus analytical variability in exposure measurements

Journal Article · Sun Dec 01 04:00:00 EST 1991 · American Industrial Hygiene Association Journal; (United States)

DOI:https://doi.org/10.1080/15298669191365199· OSTI ID:5530365

Nicas, M; Simmons, B P; Spear, R C ^[1]

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1. Center for Occupational and Environmental Health, School of Public Health, University of California, Berkeley (United States)

Measurements of 8-hr time-weighted average (TWA) exposures are subject to environmental variability and collection and analytical error. Environmental variability can be represented by the geometric standard deviation (GSD) of the lognormally distributed 8-hr TWAs; analytical variability can be represented by the coefficient of variation (CV) of the normally distributed collection and analytical errors. A mathematical expression is derived for the variance of the measured 8-hr TWAs as a function of the GSD of the true daily average exposures and the total CV of the industrial hygiene method used in monitoring. For typical values of the GSD and CV, environmental variability is far more important than analytical variability in determining the variance of the measured 8-hr TWAs. A resulting policy implication is that the Occupational Safety and Health Administration inappropriately focuses on analytical variability when determining compliance with its permissible exposure limits.

• OSTI ID: 5530365
• Journal Information: American Industrial Hygiene Association Journal; (United States), Journal Name: American Industrial Hygiene Association Journal; (United States) Vol. 52:12; ISSN AIHAA; ISSN 0002-8894
• Country of Publication: United States
• Language: English

Related Subjects

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MATHEMATICAL MODELS
MAXIMUM PERMISSIBLE EXPOSURE
OCCUPATIONAL EXPOSURE
RISK ASSESSMENT
SAFETY STANDARDS
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