Because within the ESCAPE project LUR models have been
developed in so many areas using the standardized approach
several lessons have been learned. We used a standardized and
common site selection procedure in all study areas aiming at representing
the anticipated spatial variation of air pollution in the
included cohort studies, purposely over representing street sites
(Cyrys et al., 2012). If the range in measured concentrations is small,
then this complicates the development of good LUR models. It is
therefore important that the locations of the monitoring sites
represent a large diversity of potential sources of air pollution
variability such as traffic intensity, population density, industry, etc.
It is also important to include the whole range of each characteristic
when selecting sites, and not include only the busiest road for
example, because this occasionally introduced an influential
observation during model development. Predictor variables with a
small variation also were found to be
problematic.