Occupational Exposure Assessment for Air Contaminants

357 Pages·2005·9.155 MB·\357

by  Gurumurthy Ramachandran (Author)

Occupational
Exposure
Assessment
Air
for
Contaminants
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Occupational
Exposure
Assessment
Air
for
Contaminants
Gurumurthy
Ramachandran
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Published in 2005 by
CRC Press
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Abstract
Exposure assessment is a key responsibility for most practicing occupational hygien-
ists and forms the basis for a required course in most graduate programs in industrial
hygiene. Over the last three decades, significant progress has been made, not only
in the technology of measuring air contaminants, but also in the statistical descrip-
tions of exposure distributions and exposure assessment strategies. This book
addresses the various aspects of occupational exposure assessment for air contami-
nants as a coherent body of knowledge.
The first few sections of the book describe the process of obtaining a number
that represents the value of exposure to an air contaminant (gas, vapor, or aerosol)
and the science and technology underlying this process. This necessarily involves a
discussion of the physical properties of the contaminants and the way in which
measurement technologies take advantage of these properties. Respiratory tract
deposition of aerosols is treated in sufficient depth. Concepts of measurement uncer-
tainty and error and the propagation of error in physical measurements are also
addressed. The last section describes sources of variability in exposures, including
a discussion of between- and within-worker variability, the statistics of exposure
distributions, and exposure assessment strategies for routine monitoring as well as
occupational epidemiology.
This integrated approach is intended for use in a graduate or upper-level under-
graduate course on occupational exposure assessment to airborne contaminants. The
book targets students and practitioners in occupational hygiene and other environ-
mental health disciplines.
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Author
Gurumurthy Ramachandran is associate professor in the Division of Environmental
Health Sciences of the School of Public Health at the University of Minnesota.
Dr. Ramachandran has a Bachelor’s degree in electrical engineering from the
Indian Institute of Technology, Mumbai, a Master’s degree in environmental engi-
neering from the Virginia Institute of Technology, and a Ph.D. from the University
of North Carolina, Chapel Hill. He is a Certified Industrial Hygienist (CIH).
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Preface
I have been teaching a graduate course on occupational exposure assessment for air
contaminants for almost a decade now. Occupational hygiene has lacked a book that
addressed all aspects of exposure assessment for air contaminants as a coherent body
of knowledge. This is despite the fact that exposure assessment is a key responsibility
for most practicing occupational hygienists and forms the basis for a required course
in most graduate programs in industrial hygiene. Although there are several books
available on the measurement of air contaminants, they deal solely with the descrip-
tion of the technology involved in monitoring air contaminants (again focusing only
on gases and vapors or only on aerosols). Some of the books, although excellent
reference books, are not suitable as textbooks for teaching. A good example is Air
Sampling for Evaluation of Atmospheric Contaminants, published by the American
Council of Governmental Industrial Hygienists (ACGIH) and updated every few
years. Several excellent textbooks are available for teaching aerosol science, e.g.,
those by Hinds (1999) and Vincent (1995). However, they do not address gas and
vapor monitoring. Another limitation of these books is that they fail to cover the
context in which exposures are measured, the design of exposure assessment strat-
egies, and the statistical interpretation of exposure measurements. Only one book
(Mulhausen and Damiano, 1998), to my knowledge, deals with this important topic.
I continue to recommend this excellent reference book to students. However, it does
not describe the different schools of thought regarding exposure assessment strate-
gies. It also does not describe the actual measurement methods.
I wrote this book with the intention of addressing all of these important themes
in one textbook. It is intended for use in a graduate or upper-level undergraduate
course on occupational exposure assessment to airborne contaminants. It targets
students and practitioners in occupational hygiene and other environmental health
disciplines. The book covers not only the technological aspects of measuring air
contaminants — gases, vapors, and aerosols — but also the occupational hygiene
framework within which such measurements take place. Hence, it includes a solid
treatment of exposure assessment strategies and statistics.
The book is divided into four broad sections: (1) a short introduction that
describes the framework for studying air pollutants in occupational environments,
(2) properties and measurement of gases and vapors, (3) properties and measurement
of aerosols, and (4) sources of variability in exposures and exposure assessment
strategies. The first chapter provides the context of exposure in the continuum
between contaminant sources and the final biologically relevant dose.
Given that the focus is only on the measurement of exposures and not the
measurement of dose, Section II and Section III deal with the measurement of air
contaminants — gases, vapors, and aerosols. This portion of the book deals with
the process of obtaining a number that represents the value of exposure to a con-