Analysis of spatial factors, time-activity and infiltration on outdoor generated PM2.5 exposures of school children in five European citiesAnalysis of spatial factors, time-activity and infiltration on outdoor generated PM2.5 exposures of school children in five European cities Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2023-01-112021enAtmospheric particles are a major environmental health risk. Assessments of air pollution related health burden are often based on outdoor concentrations estimated at residential locations, ignoring spatial mobility, time-activity patterns, and indoor exposures. The aim of this work is to quantify impacts of these factors on outdoor-originated fine particle exposures of school children. We apply nested WRF-CAMx modelling of PM2.5 concentrations, gridded population, and school location data. Infiltration and enrichment factors were collected and applied to Athens, Kuopio, Lisbon, Porto, and Treviso. Exposures of school children were calculated for residential and school outdoor and indoor, other indoor, and traffic microenvironments. Combined with time-activity patterns six exposure models were created. Model complexity was increased incrementally starting from residential and school outdoor exposures. Even though levels in traffic and outdoors were considerably higher, 80–84% of the exposure to outdoor particles occurred in indoor environments. The simplest and also commonly used approach of using residential outdoor concentrations as population exposure descriptor (model 1), led on average to 26% higher estimates (15.7 μg/m3) compared with the most complex model (# 6) including home and school outdoor and indoor, other indoor and traffic microenvironments (12.5 μg/m3). These results emphasize the importance of including spatial mobility, time-activity and infiltration to reduce bias in exposure estimates.http://creativecommons.org/licenses/by/4.0/Science of the Total Environment785Korhonen_et_al_Sci. Total Environ._785_2021.pdfChania [Greece]Library of TUC2023-01-11application/pdf893.4 kBfree Korhonen Antti Relvas Hélder Miranda Ana Isabel Ferreira Joana Lopes Diogo Rafael Sandra Almeida Susana Marta Faria Tiago Martins Vânia Canha Nuno Diapouli Evangelia Eleftheriadis, Konstantinos Chalvatzaki Eleftheria Χαλβατζακη Ελευθερια Lazaridis Michail Λαζαριδης Μιχαηλ Lehtomäki Heli Rumrich Isabell Hänninen, Otto Elsevier Exposure Misclassification Time-activity Spatial mobility Infiltration Microenvironment Particulate matter Health impact assessment