This book discusses the development, types and application principles of portable air purifiers in China. It analyzes the
theoretical characteristics of air purifiers under various operational conditions, and points out that the term "Clean Air
Delivery Rate" cannot be used to precisely reflect the problems that occur under various operational conditions. By comparing
theoretical and measured data, it highlights the mainfeatures of air purifiers and key points in the design process for different
applications. Calculation methods for the indoor particle concentration and the self-purification time are also provided.
The book describes the conditions for window opening in smog and for selecting air purifiers, and proposes a newmethod for
improvingtheir measurement. In closing, it includes a new assessment index.