Definition - What does Aerosol mean?
An aerosol is a suspension of particles in the atmosphere. They may form naturally, as when pine trees release alpha-pinene, an oil that suspends as a haze. Aerosols can also be artificial, in the form of air pollutants, haze and smoke. We generally refer to an aerosol as a spray that delivers a product from a can. Pesticides and medicines can also be delivered in the form of an aerosol spray.
Safeopedia explains Aerosol
There are two classes of aerosol. Primary aerosols are those that contain particles that are directly introduced. Secondary aerosols are created as a result of gas to particle conversion. The concentration of an aerosol may be determined by one of two methods. The mass concentration method calculates the mass of particles per unit of volume. The number concentration method counts the number of particles per unit of volume. Aerosols may also be monodisperse, with uniformly fixed particles, or polydisperse, with different sized particles.