Spatial and Spatiotemporal Variability of Regional Background Ultrafine Particle Concentrations in the Netherlands
Esther van de Beek, Jules Kerckhoffs, Gerard Hoek, G. Sterk, Kees Meliefste, Ulrike Gehring, Roel Vermeulen
Abstract
. We found the spatial correlation in the UFP concentrations up to 180 km and clear differences between the north and the more populated southern parts of the country. The average temporal correlation between 2 and 24 h average UFP concentrations was 0.50 (IQR: 0.36-0.61) and 0.58 (IQR: 0.44-0.75), respectively. Temporal correlation declined weakly with a distance between sites, from 0.58 for sites within 80 km of each other to 0.47 for sites farther away. The substantial spatial variation in the regional background UFP concentrations suggests that regional variation may contribute importantly to exposure contrast in nationwide health studies of UFP.