Tiny airborne particles, also called aerosols, are formed in several different ways. They can be created by sea salt from sea spray and bursting bubbles, windblown dust, and volcanic eruptions as well as from fossil fuel combustion from automobiles, ships, airplanes, and factory emissions. Aerosols can also be formed from the burning of plant materials during forest fires or in wood-burning stoves.
Once aerosols are formed, they are mixed and transported by wind within the atmosphere. Winds can carry aerosols very long distances, sometimes up to thousands of miles away from their origin. Updrafts or upward moving air and turbulence can blow aerosols to higher altitudes. Scientists use measured and simulated winds to determine where aerosols come from since they can travel so far.
Aerosols are more concentrated in areas where they are formed and tend to get diluted as they mix into the atmosphere and move away from their origin. In addition, aerosol formation within the atmosphere from emitted gases can result in higher concentrations of some aerosol particle types downwind from their origin. Natural barriers such as mountains can trap pollutants and prevent dispersion by the wind. For example, certain regions of California such as the Los Angeles basin and the Central Valley are affected by this phenomenon, which often results in visible smog.
Researchers at Scripps Institution of Oceanography at UC San Diego measure the concentration and composition of aerosols at Scripps Pier to understand the processes and sources responsible for aerosols in the region.
Doug Day, Scripps postdoctoral researcher, Climate, Atmospheric Sciences, Physical Oceanography division
To read more about how aerosols affect clouds and climate, read our story “Fine Details” at explorations.ucsd.edu/Features/2009/Fine_Details/.