This study analyzed the variability of equivalent black carbon (eBC) mass concentrations and their sources in urban Europe to provide insights into the use of eBC as an advanced air quality (AQ) parameter for AQ standards. This study compiled eBC mass concentration datasets covering the period between 2006 to 2022 from 50 measurement stations, including 23 urban background (UB), 18 traffic (TR), 7 suburban (SUB), and 2 regional background (RB) sites. The results highlighted the need for the harmonization of eBC measurements to allow for direct comparisons between eBC mass concentrations measured across urban Europe. The eBC mass concentrations exhibited a decreasing trend as follows: TR > UB > SUB > RB. Furthermore, a clear decreasing trend in eBC concentrations was observed in the UB sites moving from Southern to Northern Europe. The eBC mass concentrations exhibited significant spatiotemporal heterogeneity, including marked differences in eBC mass concentration and variable contributions of pollution sources to bulk eBC between different cities. Seasonal patterns in eBC concentrations were also evident, with higher winter concentrations observed in a large proportion of cities, especially at UB and SUB sites. The contribution of eBC from liquid fossil fuel combustion, mostly traffic (eBCT) was higher than that of residential and commercial sources (eBCRC) in all European sites studied. Nevertheless, eBCRC still had a substantial contribution to total eBC mass concentrations at a majority of the sites. eBC trend analysis revealed decreasing trends for eBCT over the last decade, while eBCRC remained relatively constant or even increased slightly in some cities.

Attention: Use of data may require contact with data provider. Please request acknowledgement details from data originators in compliance with data sharing and citation. Attribution to RI-URBANS is required from users to give appropriate credit. Information on this is included in the files. All scientific articles and reports using data need to acknowledge the project; "This study is using data that has received funding from the European Union's Horizon 2020 research and innovation programm under grant agreement No 101036245". Grants: Agencia Estatal de Investigación, Spanish Ministry of Science and Innovation, CAIAC project (PID2019-108990RB-I00); Spanish Ministry of Science and Innovation, FPI grant (PRE-2020-095498); Generalitat de Catalunya (AGAUR, SGR-447)