In contrast, the population in the outer boroughs rose continuously, except for a drop in 1945 caused by general war-time conditions. In 1933, the Tempelhof borough had an even higher average population density than the Kreuzberg borough.
A growth in population of up to 300,000 people is expected by 2010. Up to 90 % of the residential space for these inhabitants is to be created by increasing the density of existing structures: putting additional floors on buildings; converting attic and roof spaces into residential units; building on vacant lots; increasing the density of more open construction styles; extending buildings constructed in the post-war period; etc..
Lower population density results not only from high proportions of green and open spaces and lesser degrees of development. Lower density can also be due to a large amount of small business, trade and service use, as well as public facilities, etc.. These property areas are included in calculations of population density.
Detailed and current data bases of population density in specific urban areas are useful for the planning of various public departments. The Department of Urban Planning, for example, uses these figures as a basis for planning such infrastructure facilities as schools, businesses and playgrounds. Landscape Planning uses these figures for analyzing the number and accessibility of green spaces near to residential areas (cf. Map 06.05, SenStadtUmTech 1996a). Knowledge of population density also allows conclusions to be drawn regarding environmental stresses, such as calculating emissions from the use of solvents and cleaning chemicals in private residences, and determining carbon dioxide loads (cf. Map 03.08, SenStadtUm 1994b).