First outcomes of the fairmode & aquila intercomparison exercise on spatial representativeness

We are presenting an initial evaluation of the outcomes of the FAIRMODE & AQUILA intercomparison exercise (IE) on spatial representativeness (SR). To the best of our knowledge, this study provides the first attempt to quantitatively compare the range of methods used for estimating the spatial representativeness of air quality monitoring stations in Europe. As a common working basis, a shared dataset has been selected comprising modelling data and auxiliary information from the city of Antwerp. Based on this, 11 teams from 10 different countries provided their SR estimates for PM10 and NO2 at one traffic site, and for PM10, NO2 and O3 at two urban background sites. The main objective of this exercise was to evaluate the possible variety of spatial representativeness results obtained by applying the range of different contemporary approaches to a jointly used example case study. The results of the IE revealed a considerable range of variation between the different SR estimates - not only in terms of the extent and position of the SR perimeters, but also in the technical procedures and the extent of input data effectively used. These outcomes do also underline the need for (i) a more harmonized definition of the concept of “the area of representativeness” and (ii) consistent and transparent criteria used for its quantification