Geoscience Reference
In-Depth Information
Chapter 3
Nanoaerosols in the Atmosphere
A.A. Lushnikov
Abstract
This chapter presents an overview of the modern state of the kinetics
of aerosol processes in the atmosphere. The first part focuses on the principles of
modeling the dynamics of nanoaerosols in the atmosphere. Attention is then given
to the kinetics of single aerosol particles whose size is less than or comparable to
the mean free path of gaseous molecules in the atmosphere (less than 0.1 m).
The Introduction states a concept overview of the circle of atmospheric problems
related to the particles suspended in the atmospheric air (atmospheric aerosols).
The atmospheric aerosols are known to play an important role in the formation of
the climatic conditions on our planet. Although optically active aerosol particles are
relatively large, the processes of formation, growth, and behavior of smaller particles
(atmospheric nanoaerosols) attract the attention of many researchers because the
larger particles result from the smaller ones. The questions of where are these
particles from, how they grow, and what are the mechanisms of their losses are of
primary importance for modeling the aerosol states of the atmosphere at local and
global scales. The main body of this presentation popularizes an analytical approach
to the kinetics of a single aerosol particle in the transition regime (the particle size
is of the order of the molecular mean free path). I consider the condensational
growth of particles, diffusion charging of particles in the free molecule and transition
regimes, and heat exchange between the particle and the carrier gas. The version
of the flux-matching theory of Lushnikov and Kulmala serves as a basis for the
consideration of all the aforementioned processes whose efficiencies are found
analytically.
Keywords
Nanoaerosols Principles of modeling Condensation Charging
Heat transfer
