The 2017–2019 hourly particle number size distributions (PNSD) from 26 sites in Europe and 1 in the US were evaluated focusing on 16 urban background (UB) and 6 traffic (TR) sites in the framework of Research Infrastructures services reinforcing air quality monitoring capacities in European URBAN & industrial areaS (RI-URBANS) project. The main objective was to describe the phenomenology of urban ultrafine particles (UFP) in Europe with a significant air quality focus. The varying lower size detection limits made it difficult to compare PN concentrations (PNC), particularly PN10-25, from different cities. PNCs follow a TR > UB > Suburban (SUB) order. PNC and Black Carbon (BC) progressively increase from Northern Europe to Southern Europe and from Western to Eastern Europe. At the UB sites, typical traffic rush hour PNC peaks are evident, many also showing midday-morning PNC peaks anti-correlated with BC. These peaks result from increased PN10-25, suggesting significant PNC contributions from nucleation, fumigation and shipping. Site types to be identified by daily and seasonal PNC and BC patterns are: (i) PNC mainly driven by traffic emissions, with marked correlations with BC on different time scales; (ii) marked midday/morning PNC peaks and a seasonal anti-correlation with PNC/BC; (iii) both traffic peaks and midday peaks without marked seasonal patterns. Groups (ii) and (iii) included cities with high insolation. PNC, especially PN25-800, was positively correlated with BC, NO2, CO and PM for several sites. The variable correlation of PNSD with different urban pollutants demonstrates that these do not reflect the variability of UFP in urban environments. Specific monitoring of PNSD is needed if nanoparticles and their associated health impacts are to be assessed. Implementation of the CEN-ACTRIS recommendations for PNSD measurements would provide comparable measurements, and measurements of <10 nm PNC are needed for full evaluation of the health effects of this size fraction.

TRECHERA Pedro;  GARCIA-MARLÈS Meritxell;  LIU Xiansheng;  RECHE Cristina;  PÉREZ Noemí;  SAVADKOOHI Marjan;  BEDDOWS David;  SALMA Imre;  VÖRÖSMARTY Máté;  CASANS Andrea;  CASQUERO-VERA Juan Andrés;  HUEGLIN Christoph;  MARCHAND Nicolas;  CHAZEAU Benjamin;  GILLE Grégory;  KALKAVOURAS Panayiotis;  MIHALOPOULOS Nikos;  ONDRACEK Jakub;  ZIKOVA Nadia;  NIEMI Jarkko V.;  MANNINEN Hanna E.;  GREEN David C.;  TREMPER Anja H.;  NORMAN Michael;  VRATOLIS Stergios;  ELEFTHERIADIS Konstantinos;  GÓMEZ-MORENO Francisco J.;  ALONSO-BLANCO Elisabeth;  GERWIG Holger;  WIEDENSOHLER Alfred;  WEINHOLD Kay;  MERKEL Maik;  BASTIAN Susanne;  PETIT Jean-Eudes;  FAVEZ Olivier;  CRUMEYROLLE Suzanne;  FERLAY Nicolas;  MARTINS DOS SANTOS Sebastiao;  PUTAUD Jean-Philippe;  TIMONEN Hilkka;  LAMPILAHTI Janne;  ASBACH Christof;  WOLF Carmen;  KAMINSKI Heinz;  ALTUG Hicran;  HOFFMANN Barbara;  RICH David Q.;  PANDOLFI Marco;  HARRISON Roy M.;  HOPKE Philip K.;  PETÄJÄ Tuukka;  ALAUSTEY Andrés;  QUEROL Xavier; 

2026-07-13

PERGAMON-ELSEVIER SCIENCE LTD

JRC132515

1873-6750 (online),   

https://www.sciencedirect.com/science/article/pii/S016041202300017X,    https://publications.jrc.ec.europa.eu/repository/handle/JRC132515,   

10.1016/j.envint.2023.107744 (online),