Aerosol dynamics, advances

In the second edition, I have sharpened the focus on aerosol dynamics. The field has grown rapidly since its original applications to the atmospheric aerosol for which the assumption of panicle sphericity is u.sually adequate, especially for the accumulation mode. Major advances in the eighties and nineties came about when we learned how to deal with (I) the formation of solid primary panicles, the smallest individual panicles that compose agglomerates and (ii) the formation of agglomerate structures by collisions. These phenomena, which have important industrial applications, are covered in two new chapters. One chapter describes the extension of classical coagulation theory for coalescing... 

Several other chapters have been substantially rewritten to reflect the sharpened focus on aerosol dynamics. For example, the chapter on optical properties has been expanded to include more applications to polydisperse aerosols. It help.s support the chapter that follows on experimental methods in which coverage of instrumentation for rapid size distribution measurements has been augmented. Methods for the rapid on-line measurement of aerosol chemical characteristics are discussed in the chapters on optical properties and experimental methods. This chapter has been strongly influenced by the work of the Minnesota group (B. Y. H. Liu, D. Y. H, Pui, P, McMuny, and their colleagues and students) who continue to invent and perfect advanced aerosol instrumentation. Discussions of the effects of turbulence have been substantially expanded in chapters on coagulation and gas-to-particle conversion. 

The measurements of all parameters must be made on appropriate time scales. Measurements at intervals significantly longer than the time constant of the process in question will not contribute to an understanding of the dynamics of the process. Thus, wind speed should be monitored on a scale of minutes rather than hours. Ideally, the aerosol concentration data should also be acquired in the same time interval. This ideal will require advances in air sampling techniques—the traditional methods are far too slow. 

Figure 3 shows an airborne version of one recently developed fast response instrument made possible by recent advances in materials, vacuum technology, ion optics, fluid dynamics, information technology, and control technology.6 This aerosol mass spectrometer allows the real-time measurement and display of the nonrefractory, size-resolved ( 30 nm to 1500 nm) ambient aerosol particle mass loadings. Figure 4 shows the ambient fine aerosol nonrefractory composition,... 

---