Aerosol Science: Technology and Applications

Chapter 4

Aerosol Instrumentation

Da-Ren Chen¹ and David Y. H. Pui²

¹Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, USA

²Mechanical Engineering Department, University of Minnesota, USA

4.1 Introduction

Aerosol particles may consist of microscopic bits of materials from molecular clusters only a few nanometers in diameter to particles of a near macroscopic size of a fraction of a millimeter's diameter. The nominal size range of interest in aerosol research and applications is from 2 nm to 100 µm. The lower size limit, 2 nm, corresponds to the smallest particles that can be detected by an aerosol instrument such as the ultrafine condensation particle counter (CPC) (described in Section 4.4.1). However, nanoparticle and ultrafine aerosol measurements have recently attracted much attention through the national initiative on nanotechnology (http://nano.gov/). Ultrafine aerosols are formed spontaneously in the atmosphere (i.e. a nucleation event) and are emitted from transportation systems, power plants, and manufacturing processes. Engineered nanoparticles, formed from gas-phase synthesis or via the liquid-phase route, are important building blocks for nanoscale materials and devices. Nanoparticles often possess special physical (i.e. mechanical, electrical, optical, and magnetic), chemical, or biological properties compared with micrometer-sized particles of the same composition. To understand particle formation processes, it is necessary to characterize ...