Journal Article

Measurement report: Exploring the variations in ambient BTEX in urban Europe and their environmental health implications

Gille, Grégory, Duan, Xiaoli, Simon, Leïla, Bloss, William, Wang, Tao, Querol, Xavier, Fortier, Yann, Lanzi, Ludovic, Shi, Zongbo, Mihalopoulos, Nikolaos, Le Bras, Zoé, Müller, Michelle Jessy, Liakakou, Eleni, Alastuey, Andrés, Hopkins, James R., Ghersi, Véronique, Seco, Roger, Zhang, Xiaohu, Beddows, David, Lara, Rosa, Yáñez-Serrano, Ana Maria, Harrison, Roy M., An, Taicheng, Liu, Xiansheng, Baudic, Alexia, Petit, Paul, Héllen, Heidi, Hou, Siqi, Zhang, Xun, Wu, Lijie, Lewis, Alastair C., Hopke, Philip K., Monge, Marta, Salameh, Thérèse, Gohy, Marie, Sauvage, Stéphane, Dernie, James, Dufresne, Marvin, Vagnot, Marie-Pierre, Reimann, Stefan, Gros, Valérie, Chevalier, Audrey

2025

Overview

BTEX (benzene, toluene, ethylbenzene, and m-xylene,p-xylene, and o-xylene) are significant urban air pollutants. This study examines BTEX variability across 7 European countries using data from 22 monitoring sites in different urban settings (urban background, traffic, industry, and suburban background). Results indicate that the relative abundance of BTEX in urban areas follows the order toluene > benzene > m,p-xylene > o-xylene > ethylbenzene, with median mixing ratios of 266 ± 152, 163 ± 74, 129 ± 88, 53 ± 35, and 45 ± 27 ppt during the years 2017–2022, respectively. Seasonal trends show benzene had similar median concentrations across urban background, traffic, and industrial sites, indicating mixed sources. Toluene levels were highest in traffic and industrial areas, highlighting road traffic and industrial emissions. Ethylbenzene and xylenes showed equivalent levels in traffic and industrial areas but were lower in urban backgrounds. Peak BTEX levels occurred during morning and evening rush hours, linked to traffic, heating, and atmospheric stagnation. B/T ratios ranged from 0.29 ± 0.11 to 1.35 ± 0.95, and X/E ratios ranged from 1.75 ± 0.91 to 3.68 ± 0.30, indicating primary pollution from local traffic, followed by solvents, coatings, and biomass burning. Lifetime cancer risk from BTEX exposure was below the definite risk threshold (10−4) but above the permissible risk level (10−6), suggesting moderate risk from benzene and ethylbenzene, particularly in traffic and industrial areas. Additionally, the health index of BTEX at monitoring sites was generally lower than the threshold limit value, suggesting a low non-carcinogenic risk overall. This study offers essential insights into BTEX pollution in urban European environments.

• Publisher: Copernicus GmbH,Copernicus Publications
• Subject: Air monitoring / Air pollution / Benzene / Biomass / Biomass burning / Cancer / Carcinogens / Chromatography / Emissions / Environmental health / Environmental protection / Ethyl benzene / Ethylbenzene / Health risk assessment / Health risks / Hydrocarbons / Industrial areas / Industrial emissions / Industrial sites / Mass spectrometry / Measurement / Mixing ratio / Nitrogen dioxide / Outdoor air quality / p-Xylene / Paraxylene / Pollutants / Relative abundance / Risk levels / Scientific imaging / Toluene / Traffic / Urban air / Urban areas / Urban environments / VOCs / Volatile organic compounds / Xylene