Aerosol Technology

Properties, Behavior, and Measurement of Airborne Particles

William C. Hinds, Yifang Zhu

• Editore: Wiley
• Anno: 2022
• ISBN:
  9781119494065
• Edizione: 3
• Argomento: Tecnologia e ingegneria
• Categoria: Salute e sicurezza sul lavoro

AEROSOL TECHNOLOGY

An in-depth and accessible treatment of aerosol theory and its applications

The Third Edition of Aerosol Technology: Properties, Behavior, and Measurement of Airborne Particles delivers a thorough and authoritative exploration of modern aerosol theory and its applications. The book offers readers a working knowledge of the topic that reflects the numerous advances that have been made across a broad spectrum of aerosol-related application areas. New updates to the popular text include treatments of nanoparticles, the health effects of atmospheric aerosols, remote sensing, bioaerosols, and low-cost sensors. Additionally, readers will benefit from insightful new discussions of modern instruments.

The authors maintain a strong focus on the fundamentals of the discipline, while providing a robust overview of real-world applications of aerosol theory. New exercise problems and examples populate the book, which also includes:

• Thorough introductions to aerosol technology, key definitions, particle size, shape, density, and concentration, as well as the properties of gases
• Comprehensive explorations of uniform particle motion, particle size statistics, and straight-line acceleration and curvilinear particle motion
• Practical discussions of particle adhesion, Brownian motion and diffusion, thermal and radiometric forces, and filtration
• In-depth examinations of sampling and measurement of concentration, respiratory deposition, coagulation, condensation, evaporation, and atmospheric aerosols

Perfect for senior undergraduate and junior graduate students of science and technology, Aerosol Technology: Properties, Behavior, and Measurement of Airborne Particles will also earn a place in the libraries of professionals working in industrial hygiene, air pollution control, climate science, radiation protection, and environmental science.

1
Introduction

The microscopic particles that float in the air are of many kinds: resuspended soil particles, smoke from power generation, photochemically formed particles, salt particles formed from ocean spray, and atmospheric clouds of water droplets or ice particles. They vary greatly in their ability to affect not only visibility and climate, but also our health and quality of life. These airborne particles are all examples of aerosols. An aerosol is defined in its simplest form as a collection of solid or liquid particles suspended in a gas. Aerosols are two‐phase systems, consisting of the particles and the gas in which they are suspended. They include a wide range of phenomena such as dust, fume, smoke, mist, fog, haze, clouds, and smog. The word aerosol was coined in about 1920 as an analog to the term hydrosol, a stable liquid suspension of solid particles. Although the word aerosol is popularly used to refer to pressurized spray‐can products, it is the universally accepted scientific term for particulate suspensions in a gaseous medium and is used in that sense in this book.

Aerosols (first data row of Table 1.1) are one of the several types of particulate suspensions listed in Table 1.1. All are two‐component systems having special properties that depend on size of the particles and their concentration in the suspending medium. All have varying degrees of stability that also depend on particle size and concentration.

An understanding of the properties of aerosols is of great practical importance. It enables us to comprehend the process of cloud formation in the atmosphere, a key link in the hydrological cycle. Aerosol properties influence the production, transport, and ultimate fate of atmospheric particulate pollutants. Measurement and control of particulate pollutants in the occupational and general environments require the application of this knowledge. Aerosol technology has commercial application in the manufacture of spray‐dried products, fiber optics, and carbon black; the production of pigments; and the application of pesticides. Because the toxicity of inhaled particles depends on their physical as well as their chemical properties, an understanding of the properties of aerosols is required to evaluate airborne particulate hazards. The same knowledge is used in the administration of therapeutic aerosols for the treatment of respiratory and other diseases.

Aerosol technology is the study of the properties, behavior, and physical principles of aerosols and the application of this knowledge to their measurement and control. The particulate phase of an aerosol represents only a very small fraction of its total mass and volume, less than 0.0001%. Bulk properties of aerosols, such as viscosity and density, differ imperceptibly from those of pure air. Consequently, to study the properties of aerosols, one must adopt a microscopic point of view. This reduces the problem of understanding the complex properties of aerosols to that of understanding the properties of individual particles. The microscopic approach considers one particle at a time and deals with questions about the forces on that particle, its motion, and its interaction with the suspending gas, with electromagnetic radiation, and with other particles.

Table 1.1 Types of Particulate Suspensions.

	Type of Suspended Particles
Suspending Medium	Gas	Liquid	Solid
Gas	—	Fog, mist, spray	Fume, dust
Liquid	Foam	Emulsion	Colloid, suspension, slurry
Solid	Sponge	Gel	Alloy

At the beginning of the 20th century, the study of aerosols was at the forefront of physical science because aerosols represented the smallest observable division of matter. Aerosol science contributed to the early understanding of Brownian motion and diffusion, Millikan's measurement of the charge on the electron, and Wilson's cloud chamber experiments for the study of ionizing radiation. This classical period of aerosol science research continued through the first half of the century, concluding with the publication of The Mechanics of Aerosols by Fuchs in 1955. Following World War II, and particularly during the 1970s and 1980s, aerosol technology grew in importance because of an increased environmental awareness and a concern for the health effects arising from air pollution in community and occupational environments. The field expanded rapidly in the ...