Airborne transmission

Bacteria and viruses showing the ability to be transmitted through aerosols are considered to be airborne. Viruses such as Human Influenza viruses are transmissible through aerosols.

Theory behind Airborne Transmission
Before the theory is explained, a phenomenon will first be presented. Everyone has felt a cool ocean breeze on their face before, but did they know that the ocean breeze contains more ocean bacteria in its few aerosolized water particles than in 1m³ of ocean water?

When air moves rapidly above a water surface, some particles aerosolize and are carried in the air. It might seem by chance that some particles and not others are carried, but this is not the case and the phenomenon of surface tension plays a role.

Water forms fairly strong bonds with itself due to hydrogen bonding. However, when something gets in the way of water molecules, and disturbs the lattice that they form, water can no longer make strong bonds with each other and water molecules can be separated more easily. In the case of the ocean breeze, when wind passes above ocean water, it picks up portions of water with the weakest bonds, which are most easily aerosolized. Bacteria have surface proteins that are charged and attract water molecules, they act as particles that disturb the lattice of water molecules, so places on the surface where bacteria reside have weakened water molecule bonds and so become aerosolized.

This brings us to the requirements for an airborne virus or bacterium. There must be charged proteins present on the surface that will lower surface tension of water allowing aerosolization of the particles.