1. Oxidative potential of subway PM2.5.
- Author
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Moreno, Teresa, Kelly, Frank J., Dunster, Chrissi, Oliete, Ana, Martins, Vânia, Reche, Cristina, Minguillón, Maria Cruz, Amato, Fulvio, Capdevila, Marta, de Miguel, Eladio, and Querol, Xavier
- Subjects
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PARTICULATE matter , *OXIDATION , *AIR quality , *VITAMIN C , *GLUTATHIONE - Abstract
Air quality in subway systems is of interest not only because particulate matter (PM) concentrations can be high, but also because of the peculiarly metalliferous chemical character of the particles, most of which differ radically from those of outdoor ambient air. We report on the oxidative potential (OP) of PM 2.5 samples collected in the Barcelona subway system in different types of stations. The PM chemical composition of these samples showed typically high concentrations of Fe, Total Carbon, Ba, Cu, Mn, Zn and Cr sourced from rail tracks, wheels, catenaries, brake pads and pantographs. Two toxicological indicators of oxidative activity, ascorbic acid (AA) oxidation (expressed as OP AA μg −1 or OP AA m −3 ) and glutathione (GSH) oxidation (expressed as OP GSH μg −1 or OP GSH m −3 ), showed low OP for all samples (compared with outdoor air) but considerable variation between stations (0.9–2.4 OP AA μg −1 ; 0.4–1.9 OP GSH μg −1 ). Results indicate that subway PM toxicity is not related to variations in PM 2.5 concentrations produced by ventilation changes, tunnel works, or station design, but may be affected more by the presence of metallic trace elements such as Cu and Sb sourced from brakes and pantographs. The OP assays employed do not reveal toxic effects from the highly ferruginous component present in subway dust. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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