Information on the study population are clearly crucial for any assessment.  This is needed not only to indicate how many people might be at risk, and where they live, but also as a basis for determining how susceptible and vulnerable they might be to exposures (or what accesss they might have to environmental resources and benefits).  Essential information thus includes:

• Population distribution
• Gender and age structure
• Occupation, travel, consumption and behaviour
• Socio-economic status

Census data

Population data are today widely available.  They are collected on a routine basis through national national censuses, and are usually provided by the national agencies concerned (sometimes, though not always freely).  At European level they collated and distributed by Eurostat.  Typically, the data include not only numbers of residents by age and gender, but also information on factors such as occupation, education, income/assets, travel behaviours and various indicators about the home.

The limitations of census data nevertheless need to be recognised.  They include inevitable under-reporting of some population sub-groups (especially homeless and transient people), differences in timing of the censuses between different countries, and differences in the definition of the base population and of many of the detailed characteristics.  The last of these reasons means that it remains difficult to derive a common measure of socio-economic status that can be used across the EU.  In recent years, also, some countries have moved to using sample censuses, rather than full population counts, while census data may be available only at a relatively coarse (and sometimes variable) spatial resolution, limiting their use in more detailed assessments.

Other sources of population, demographic and socio-economic data

Data are also available from a number of other, less official and less routine, sources.  Social, housing, health and education departments collect and hold an extensive range of information on the population, which may be valuable in assessing exposures and vulnerability.  For reasons of confidentiality, however, these data are not always readily available, and may not be directly linked or structured in a common way (e.g. based on the same administrative units), so difficulties can be met in accessing and using them.  Some countries also conduct regular behavioural or time use surveys across samples of the population.  Likewise, commercial surveys are widely undertaken, which can give valuable (and often very detailed) information on public behaviours and lifestyles - though access to these data are often limited or costly.  

In addition, information on population distribution and socio-economic activities is available from a range of less obvious sources.  Satellite-based land cover surveys, for example, can provide a wealth of information on residential density and land use distribution; night-time light emissions data give a simple, regularly updates and very vivid indication of population patterns.   Several studies have thus been carried out using these types of data to derive detailed population distribution maps.  

Links to data sources

The link below gives access to an EU population data set comprising population numbers (stratified by age group and gender) at 1 km and LAU-2 (equivalent to commune) level, derived by linking national census data to land cover data.  The same link also provides information on sources of national data. 

• EU population data: LAU2

Other population data sets, at different spatial resolutions and developed using a variety of methods, are also available in the Population numbers/distribution archive in the Toolkit (see link below).