In general conversation, the term aerosol is often used to represent a spray can, such as an air freshener or spray paint canister. In science, “aerosol” refers specifically to a suspension of solid particles or liquid droplets in air. They are produced in many ways from countless different sources, the most prevalent of which are ocean spray and volcanic activity (natural sources) and industrial emissions.
Aerosol influence many aspects of modern life. They are responsible for city wide hazes seen in many urban areas (e.g. Los Angeles) and contribute a significant risk to human health. They have an important role in regulating climate, yet are poorly constrained in global climate models. Aerosol emitted by volcanic activity can cause rapid worldwide perturbations to climate and negatively impact air travel. Aerosol have many beneficial uses, such as in delivering medication to the lungs, in many industrial processes, and by allowing efficient combustion of fuels to occur. An excellent example of the increased combustibility of aerosolized media, in this case custard powder, comes from the BBC show, QI (link).
The chemistry and microphysical properties of aerosol particles differ significantly from the same material in a bulk sample. An aerosol ensemble has a very large surface-to-volume ratio leading to significant interface effects, and may exist in highly supersaturated and supercooled states in the absence of nucleating sites for ice or crystal formation. Fully understanding and quantifying the unique properties of aerosol is an ongoing challenge in physical chemistry, with numerous research groups around the world focused on laboratory and theoretical explorations of aerosol dynamics. It is my intention on this website to highlight my personal research contributions to aerosol science and to present the basic physics and chemistry governing their behavior.