Air quality in underground railway stations has emerged as a pressing public health issue, particularly due to the high concentrations of particulate matter (PM10 and PM2.5) that can accumulate in these confined spaces. A groundbreaking study led by Valisoa M. Rakotonirinjanahary from the University of Lille, in collaboration with SNCF Holding, sheds light on this critical concern by introducing a novel methodology for establishing typical daily profiles of PM concentrations in these environments.
The research, which spans a comprehensive five-year measurement series in a Parisian underground railway station, reveals significant insights into the variability of PM concentrations. “Despite the numerous measurements taken, we lacked a clear understanding of how these concentrations fluctuate from one station to another,” said Rakotonirinjanahary. The study addresses this gap by employing a rigorous data cleaning process that identifies operational periods and filters out inconsistent data, combined with a linear regression model to produce reliable daily profiles.
Notably, the research identifies distinct patterns in PM concentrations. Weekdays exhibit two pronounced peaks during the morning and evening rush hours, with an average daytime concentration of 193 µg/m³, while weekends show a more stable and lower average of 157 µg/m³. These findings are pivotal for urban planners and construction professionals, as they highlight the need for enhanced ventilation and air quality management strategies in underground transport systems.
The study also uncovers seasonal variations, with PM concentrations peaking in the summer months, reaching levels as high as 400 µg/m³, while winter months record lower concentrations. This indoor seasonal evolution contrasts sharply with outdoor air quality trends, where winter often sees higher particulate levels. “Our results indicate that the optimal time for conducting experiments to obtain reliable profiles is during the spring months,” Rakotonirinjanahary noted, emphasizing the importance of timing in air quality assessments.
For the construction sector, these insights could drive innovations in design and engineering practices, particularly in the development of underground facilities. Understanding PM concentration profiles allows for the integration of advanced air filtration systems and improved ventilation designs, ultimately leading to healthier environments for commuters.
As cities continue to expand their underground transit systems, the implications of this research extend beyond health concerns to influence regulatory frameworks and construction standards. By prioritizing air quality in the design and operation of underground railway stations, stakeholders can significantly enhance public health outcomes and contribute to more sustainable urban environments.
This important research was published in ‘Indoor Environments’, a journal dedicated to the study of indoor air quality and its implications. For more information about the lead author and their work, visit lead_author_affiliation.