Aerosols: Tiny Particles, Big Impact
Source: NASA Earth Observatory[02-Nov-2010] Take a deep breath. Even if the air looks clear, it's nearly certain that you'll inhale tens of millions of solid particles and liquid droplets. These ubiquitous specks of matter are known as aerosols, and they can be found in the air over oceans, deserts, mountains, forests, ice, and every ecosystem in between. They drift in Earth's atmosphere from the stratosphere to the surface and range in size from a few nanometers - less than the width of the smallest viruses - to several several tens of micrometers - about the diameter of human hair. Despite their small size, they have major impacts on our climate and our health.
Check out this article for more information on the types of natural and human-made aerosols, their global patterns, relationships with climate and clouds, and how scientists measure them. Aerosols: Tiny Particles, Big Impact