ABSTRACT
The Earth’s atmosphere is a two-phase system consisting of gases and particles (solid or liquid). This means the entire atmosphere is, by definition, an aerosol. The number concentration and size distribution of environmental or atmospheric aerosol particles are highly variable in space (marine and continental, or boundary layer and free troposphere) and time (summer and winter). Although the total mass of these particles is small compared with the total mass of atmospheric gases, atmospheric particles play an important role in today’s research on climate change, air pollution, and human health.
