The hygienic significance of air movement consists, first of all, in that it promotes ventilation (aeration) of residential quarters and the buildings located there, leads to the very purification of the atmosphere from pollution. In addition, the wind provides the transfer of heat and moisture from one area to another, that is, it is a climate and weather-forming factor.
The effect of air movement directly on the human body is reduced to an increase in heat transfer from the surface of the body. In conditions of low ambient temperature, it has an adverse effect, contributing to excessive cooling and the development of colds. On hot days, wind is a favorable factor, increasing heat transfer by convection and evaporation, protecting the body from overheating. A strong, prolonged wind can cause a deterioration in the well-being and neuropsychic state of a person, cause an exacerbation of some chronic diseases. The high speed of air movement (more than 20 m / s) violates the normal breathing rhythm, increases the load when walking and performing physical work in the open air. The most favorable wind speed in the summer with ordinary light clothing is considered to be 1-4 m / s, depending on air temperature and the state of the body (rest, work).
In residential premises, classes, classrooms, hospital rooms, the comfortable state of the air environment (with other optimal microclimate indicators) determines the air mobility for the cold period of 0.01 m / s, for the warm period of the year 0.15 m / with; in industrial premises an air speed of 0.3 m / s is permissible. At lower values, there is insufficient air exchange, a feeling of stagnant, still air. Air velocities exceeding 0.3 m / s cause an unpleasant feeling of draft, which is often the cause of local or general cooling and the occurrence of colds.
When installing ventilation in residential and communal buildings, it is necessary to set such air speeds that contribute to maintaining thermal comfort.