Elsevier

Atmospheric Environment

Volume 148, January 2017, Pages 230-238
Atmospheric Environment

Oxidative potential of subway PM2.5

https://doi.org/10.1016/j.atmosenv.2016.10.045Get rights and content
Under a Creative Commons license
open access

Highlights

  • Oxidative activity shows considerable variation between different subway platforms.

  • Subway PM oxidative potential is not linked to ventilation or tunnel night works.

  • Highest oxidative potential coincide with PM with higher levels of Cu, As and Sb.

  • The strongly Fe component in PM subway does not produce any obvious toxic effect.

  • Lowest oxidative stress was found at station with PSDs.

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 PM2.5 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 OPAA μg−1 or OPAA m−3) and glutathione (GSH) oxidation (expressed as OPGSH μg−1 or OPGSH m−3), showed low OP for all samples (compared with outdoor air) but considerable variation between stations (0.9–2.4 OPAA μg−1; 0.4–1.9 OPGSH μg−1). Results indicate that subway PM toxicity is not related to variations in PM2.5 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.

Keywords

Particulate matter
Oxidative potential
Toxicity
PM chemistry
Subway air quality
Airborne metals

Cited by (0)