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2001 | Buch

Understanding Radioactive Aerosols and Their Measurement

verfasst von: Stephen D. Schery

Verlag: Springer Netherlands

Buchreihe : Environmental Science and Technology Library

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Über dieses Buch

This book is intended as an introduction to radioactivity and aerosols for the scientifically literate reader who has had no previous exposure to either of these subjects. Although its main focus is radioactive aerosols, on the road to this subject I provide short, somewhat independent introductions to both radioactivity and aerosols, with some emphasis on experimental aspects. The audience I have in mind is upper-level undergraduates or beginning graduate students with a minimum background of introductory college courses in physics, chemistry, and calculus. This book may also be useful to "crossover" professional- professionals in other fields of science and engineering, for example biology or geoscience, who would like a step-by-step introduction to this subject matter from the physical science perspective. In writing this book I have been sensitive to requests and suggestions from students who need some background in this subject matter but will probably not specialize in it. These students are bright, but busy, and they sometimes feel overwhelmed by the mass of information in advanced, comprehensive texts. No matter how noble the intentions of the authors (or the teachers assigning the books!), these students often do not have time to read such books through cover to cover, and they fmd it difficult to pick out a coherently-connected subset of the material. Furthermore, modern students studying an interdisciplinary subject like radioactive aerosols are likely to be more diversified than ever, in educational background, in interests, and in preparation.

Inhaltsverzeichnis

Frontmatter
Chapter 1. Radioactivity and Aerosols: An Introduction
Abstract
This book deals with the subject of radioactive aerosols in the indoor and outdoor atmospheres, with due regard to the point of view of people interested in experimental aspects such as measurement and instrumentation. Since little or no preparation is assumed in the underlying subjects of radioactivity and aerosols, we provide fairly self-contained introductions to both before focusing on the combined subject of interest: radioactive aerosols.
Stephen D. Schery
Chapter 2. Radioactivity and the Interaction of Nuclear Radiation With Matter
Abstract
In this chapter we want to discuss two topics: decay of radioactive atoms and the interaction with matter of nuclear radiation emitted by decay of radioactive atoms. The words “radionuclides” could be used interchangeably with “radioactive atoms” in this chapter without confusion. Nuclear radiation is sometimes just called “radiation” if there is no chance of confusion with other forms of radiation such as light and radio waves. The most important forms of nuclear radiation from the atmospheric and environmental radioactivity standpoint are alpha particles (helium nuclei), beta particles (high-energy electrons or positrons), and gamma rays (high-energy photons, i.e., high-energy electromagnetic bundles of energy).
Stephen D. Schery
Chapter 3. Measurement of Nuclear Radiation and Radioactivity
Abstract
In this chapter we will focus on nuclear radiation as a tool for measuring radionuclides in environmental samples. For example, we might determine the activity of214Pb in a compacted filter by counting the 352-keV gamma rays emitted during decay of214Pb, or the activity of239Pu collected on the surface of a filter by measurement of its 5.16-MeV alpha particles. As pointed out in Chapt. 2, with radioactive substances it is usually easier to measure the nuclear radiation (alpha particles, beta particles, gamma rays, etc.) emitted by the radioactive atoms than to measure the radioactive atoms themselves. It can be difficult to separate the radioactive atoms from stable atoms, and the collective mass of the radioactive atoms is usually too small to measure directly. However, there are some exceptions as will be mentioned below.
Stephen D. Schery
Chapter 4. Physical Behavior of Aerosol Particles
Abstract
In this chapter we want to discuss the physical behavior of aerosol particles in the atmosphere. Except where noted otherwise, this discussion pertains to aerosols in general, whether radioactive or not. Foremost is the subject of the motion of aerosol particles relative to a surrounding air mass. How does an aerosol particle get from one position to another? What are the laws that control this movement? This discussion will involve two important classes of motion, which we call uniform motion and diffusive motion. There is a third major process by which aerosol particles get transported about the earth’s surface: this is by motion of the air mass itself (wind, turbulence, convective air currents, fan-induced circulation, etc.). However, motion of air masses is really a separate subject since it is not directly dependent on their aerosol content. The effect of such motion on aerosol transport will be left for discussion in later chapters.
Stephen D. Schery
Chapter 5. Aerosol Measurement
Abstract
In this chapter we discuss some of the major techniques for measuring aerosols, particularly radioactive aerosols. We first review some of the common techniques for measuring aerosols whether radioactive or not. It will be evident that only a subset of these approaches is suitable for radioactive-aerosol applications. Two physical processes particularly important for collection and measurement of aerosol particles are impaction and diffusion to surfaces. We provide background on these processes before going on to discuss their application to aerosol collection and measurement. We then focus specifically on radioactive aerosols. Many of our examples will involve the use of air filters to measure atmospheric activity concentrations, since this is probably the single most common approach to radioactive-aerosol measurement.
Stephen D. Schery
Chapter 6. Radioactive Aerosols: Atmospheric Sources and Indoor Models
Abstract
In this chapter we begin a more detailed discussion of the behavior of radioactive aerosols in the atmospheric environment. We want to cover both the indoor and outdoor environments. How do radioactive aerosols get to indoor and outdoor airspaces? How are they transported from one place to the next? How are they removed? In this chapter we focus on sources of indoor and outdoor radioactive aerosols and then discuss indoor models. In the next chapter we will deal with tracer applications, outdoor models, and outdoor transport.
Stephen D. Schery
Chapter 7. Radioactive Aerosols: Tracer Applications and Outdoor Transport
Abstract
This final chapter continues the subjects of transport and modeling of radioactive aerosols by expanding discussion to the outdoor environment. We start with a discussion of wet (involving rain and snow) and dry (not involving rain and snow) deposition of aerosol particles to the earth’s surface. These are major removal processes for outdoor aerosol particles that, explicitly or implicitly, must be incorporated into most outdoor transport models. We next introduce the use of radioactive aerosols for tracer and timing studies. This is an important application involving radioactive aerosols that has proven to be useful for understanding a number of physical processes in the outdoor atmosphere such as atmospheric circulation patterns and aerosol-particle removal rates. Although tracer techniques are used to study complex processes in the atmosphere, many of the basic methods and examples can be understood as a “stand-alone” subject without prior exposure to atmospheric transport models.
Stephen D. Schery
Backmatter
Metadaten
Titel
Understanding Radioactive Aerosols and Their Measurement
verfasst von
Stephen D. Schery
Copyright-Jahr
2001
Verlag
Springer Netherlands
Electronic ISBN
978-94-010-0786-3
Print ISBN
978-0-7923-7176-2
DOI
https://doi.org/10.1007/978-94-010-0786-3