The definition of air flow is the movement of air from one area to another. It is the result of differences in air pressure between two points. Air flow is an important part of the natural environment, as it helps to regulate temperature, humidity, and other atmospheric conditions. Air flow is also important for the circulation of oxygen and other gases in the atmosphere. In addition, air flow is responsible for the movement of dust, pollen, and other particles in the atmosphere. Air flow is also responsible for the formation of clouds and precipitation. In terms of human activities, air flow is important for ventilation, heating, and cooling of buildings and other structures. Air flow is also important for the operation of aircraft, as it helps to provide lift and thrust. Air flow is also important for the dispersal of pollutants in the atmosphere, as it helps to disperse them over a wide area. Finally, air flow is important for the dispersal of sound waves, as it helps to carry sound from one place to another.