ABSTRACT
This chapter focuses on aerosols made by physical routes and the next by chemical ones. Aerosols are suspensions of solid or liquid particles in gases. Smoke, dust, mist, fog, haze and cloud are names that are used frequently for aerosols that can be generated by physical or chemical routes. Atomization or nebulization of fluids is by far the dominant way to generate liquid aerosols. A lot of research is dedicated to controlling the average droplet size and size distribution of the fuel. One can distinguish two basic types of two-fluid atomizers: internal-mixing type and external-mixing type. Nebulizers are atomizers of low throughput that are attractive for the generation of test aerosols for instrument development, inhalation of medical aerosols, bioaerosols, material synthesis etc. One of the most popular nebulizers, especially for filtration studies, are those containing a Laskin nozzle. Ultrasonic nebulizers are quite popular and are used widely for humidification of indoor spaces.
