Analyses of the influence of the physical environment on health usually take a specific geographical area or location as a starting point: the indoor environment of the home, environmental problems of one or more neighborhoods, cities, regions, countries or the global environment. Authors in this section of the journal describe public health problems that confront us at those different levels as well as the advantages and disadvantages of focusing analyses solely on one of these separate levels. Expositions are often better measurable at a certain geographical level and political powers to intervene are geographically defined.
