Geographic variation

The text on this page is taken from an equivalent page of the IEHIAS-project.

The geographic distribution of environmental health impacts is geographically far from uniform. Some hazards and benefits are clustered in specific areas, others are more ubiquitous but still vary in intensity depending on environmental factors such as geology, climate, soils or topography. Human populations are markedly uneven, both in terms of their density and their susceptibility to risk. These geographic variations have a fundamental influence on how assessments need to be designed. They need to be reflected in three crucial aspects of the analysis:

• the geographic location and extent of the assessment;
• the spatial resolution at which the analysis is done;
• the geographical format (zone design) used to represent the data during both analysis and display of the results.