Nocturnity, 24 hours cities and their socio-environmental effects

The progressive expansion of cities has meant an increase in the urban capacity to provide services, resulting in the use of night hours for the development of activities that normally take place during the day. The change in the urban social and environmental dynamics that supposes the increase of the nocturnal activities constitutes an element to consider in the planning of the cities. Thus, invoking the principles of efficiency and diversity in the use of space, several cities around the world are gradually transformed into cities 24 hours. This article studies the phenomenon of urban nocturnal spatiality in the light of four elements that facilitate its understanding and implications: the idea of cities 24 hours, their relevance and scope; the externalities that from the point of view of social welfare mean the expansion of nocturnal activities; the environmental impact of the development of cities 24 hours; Finally, an adequate urban planning scenario is proposed which, in addition to contemplating the spatial dimension, occupies and emphasizes the importance of the temporal dimension, since the night as an event a cyclical storm has a decisive influence on the dynamics of the cities.