Origin of inorganic and organic components of PM2.5 in subway stations of Barcelona, Spain

The present work assesses indoor air quality in stations of the Barcelona subway system. PM2.5 concentrations on the platforms of 4 subway stations were measured during two different seasons and the chemical composition was determined. A Positive Matrix Factorization analysis was performed to identify and quantify the contributions of major PM2.5 sources in the subway stations. Mean PM2.5 concentrations varied according to the stations design and seasonal periods. PM2.5 was composed of haematite, carbonaceous aerosol, crustal matter, secondary inorganic compounds, trace elements, insoluble sulphate and halite. Organic compounds such as PAHs, nicotine, levoglucosan and aromatic musk compounds were also identified. Subway PM2.5 source comprised emissions from rails, wheels, catenaries, brake pads and pantographs. The subway source showed different chemical profiles for each station, but was always dominated by Fe. Control actions on the source are important for the achievement of better air quality in the subway environment. © 2015 The Authors.

The present study was supported by the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 315760 HEXACOMM, the Spanish Ministry of Economy and Competitiveness and FEDER funds ( METRO CGL2012-33066 ), and the IMPROVE LIFE project ( LIFE13 ENV/ES/000263 ). Fulvio Amato is beneficiary of an AXA Research Fund postdoctoral grant. The authors would like to thank the Transports Metropolitans de Barcelona METRO staff who arranged the sampling campaign and contributed actively to this work. Appendix A

Peer reviewed