Skip to Main Content
Skip Nav Destination

The atmosphere of the Earth is a colloidal system that contains liquid and solid aerosol particles beside gas-phase components. Aerosol particles are ubiquitous and play an important role in the physics and chemistry of the atmosphere, especially in the lower 10–15-km layer, the troposphere. Above a turbulent layer that extends from the surface to an altitude of 1–2 km, the troposphere is filled with a homogeneous particle population that constitutes the background aerosol (Junge, 1963).

There is great scientific interest in atmospheric aerosols, stemming from a recognition of their significance in affecting our weather and climate. Aerosol particles change Earth’s heat balance both directly and indirectly. They scatter and absorb solar radiation, thereby modifying the planetary albedo; this is called the direct effect. Aerosol particles may act as cloud condensation nuclei (CCN), thereby modifying the physical and radiative properties of clouds; this is known as the indirect effect (Fig. 1). The term radiative forcing refers to changes in the planetary radiation budget, caused by anthropogenic or external influences; it is measured in watts per square meter (Wm−2), and a positive value means net warming, whereas a negative value indicates net cooling of an air column above the Earth’s surface (IPCC, 1996).

In addition to being agents of climate change, aerosol particles affect our environment in various ways. For example, high concentrations of particles can cause serious visibility degradation; some particle types are notable for their contribution to atmospheric acidity, whereas other types are important because of their health effects.

You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
Close Modal

or Create an Account

Close Modal
Close Modal