Vapour

When warm exhaust air rich in water vapour (for example, from a cooling tower, a drying plant or a chimney) is released, it may mix with cooler outside air, leading to condensation and thus the formation of water droplets. Such a mist of droplets – the visible vapour – can, in certain cases, have microclimatic effects, such as reduced visibility, shading effects or, at outdoor temperatures below freezing, icing.