What are aerosols?
Aerosols are small particles suspended in the atmosphere. They are often not or barely visible to the human eye, yet their impact on climate, weather, health, and ecology are significant. This page introduces the various major types of aerosols, and explains why researching them is important.
Aerosols range in size from a few tens of nanometers—less than the width of the smallest viruses—to several tens of micrometers—about the diameter of human hair. The size and composition of aerosol particles affects how far they can travel around the world, their interactions with solar and thermal radiation, and their potential effects on health. Aerosols injected into the atmosphere directly are known as ‘primary aerosols’. Sea spray, mineral dust, smoke, and volcanic ash are all primary aerosols. Secondary aerosols are aerosols which were emitted in another form (e.g. gases), then become aerosol particles after going through chemical reactions in the atmosphere, such as sulfate aerosols from volcanoes or industrial emissions. All aerosols can also undergo further chemical changes, referred to as ‘aging effects’. Some more information about these various aerosol types is given in this comprehensive article.
