Exposure to airborne particulate matter in the subway system

Abstract

The Barcelona subway system comprises eight subway lines, at different depths, with different tunnel dimensions, station designs and train frequencies. An extensive measurement campaign was performed in this subway system in order to characterise the airborne particulate matter (PM) measuring its concentration and investigating its variability, both inside trains and on platforms, in two different seasonal periods (warmer and colder), to better understand the main factors controlling it, and therefore the way to improve air quality. The majority of PM in the underground stations is generated within the subway system, due to abrasion and wear of rail tracks, wheels and braking pads caused during the motion of the trains. Substantial variation in average PM concentrations between underground stations was observed, which might be associated to different ventilation and air conditioning systems, characteristics/design of each station and variations in the train frequency. Average PM2.5 concentrations on the platforms in the subway operating hours ranged from 20 to 51 and from 41 to 91 μg m(-3) in the warmer and colder period, respectively, mainly related to the seasonal changes in the subway ventilation systems. The new subway lines with platform screen doors showed PM2.5 concentrations lower than those in the conventional system, which is probably attributable not only to the more advanced ventilation setup, but also to the lower train frequency and the design of the stations. PM concentrations inside the trains were generally lower than those on the platforms, which is attributable to the air conditioning systems operating inside the trains, which are equipped with air filters. This study allows the analysis and quantification of the impact of different ventilation settings on air quality, which provides an improvement on the knowledge for the general understanding and good management of air quality in the subway system.

Sources of particulate matter components in the Athabasca oil sands region: investigation through a comparison of trace element measurement methodologies

“…The combination of anthropogenic and crustal elements present in these factors could have arisen from mining-related activities such as mechanical abrasion of excavated materials within crushers. Activities such as combustion-powered mechanical abrasion could result in a full-range of PM, from ultrafine to coarse, part of which would be considered to be PM 2.5 (Okuda et al, 2007;Martins et al, 2015). Other elements within these mixed sources could have been the result of further industrial activity at the different plant sites, which are known to be large emitters of elements such as Ni, Cu, Cr, Zn, and Se (Environment and Climate Change Canada, 2015).…”

Origin of inorganic and organic components of PM 2.5 in subway stations of Barcelona, Spain

“…In order to have PM characterisation representative of the whole platform, the PM mass and chemical compounds concentrations reported here are those corrected for spatial variation at each platform, based on the measurements described in Martins et al (2015), where the PM 2.5 concentrations were measured at four different sites along the platforms.…”

Deposition of aerosol particles from a subway microenvironment in the human respiratory tract

“…The techniques and procedures of the experimental study are described in detail elsewhere (Martins et al, 2015a), and will be only briefly summarised here. PM 2.5 samples were collected daily on quartz microfibre filters using a high volume sampler (HVS, Model CAV-A/MSb, MCV) over 19 h (from 5 a.m. to midnight, subway operating hours).…”

“…A monodispersed aerosol size distribution was considered with a MMAD of 0.21 mm and a GSD of 1.15. Martins et al (2015a), and will only be summarised here. Table 1 displays the average PM 2.5 concentrations measured at each subway station and in the outdoor environment.…”