Properties and sources of individual particles and some chemical species in the aerosol of a metropolitan underground railway station

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Abstract

Aerosol samples in PM10-2.0 and PM2.0 size fractions were collected on the platform of a metropolitan underground railway station in central Budapest. Individual aerosol particles were studied using atomic force microscopy, scanning electron microscopy and transmission electron microscopy with energy-dispersive X-ray spectrometry and electron diffraction. The bulk aerosol samples were investigated by 57Fe Mössbauer spectroscopy, and they were subjected to chemical speciation analysis for Cr. The particles were classified into groups of iron oxides and iron, carbonates, silicates, quartz and carbonaceous debris. Electron micrographs showed that the Fe-rich particles in the PM2.0 size fraction typically consisted of aggregates of nano-sized hematite crystals that were randomly oriented, had round shapes and diameters of 5-15 nm. In addition to hematite, a minor fraction of the iron oxide particles also contained magnetite. In addition, the PM2.0-fraction particles typically had a rugged surface with layered or granular morphologies. Mössbauer spectroscopy suggested that hematite was a major Fe-bearing species in the PM10-2.0 size fraction; its mass contribution to the Fe was 36%. Further constituents (ferrite, carbides and FeOOH) were also identified. The water soluble amounts of Cr for the underground railway station and city center were similar. In the PM10-2.0 size fraction, practically all dissolved Cr had an oxidation state of three, which corresponds to ambient conditions. In the PM2.0 size fraction, however, approximately 7% of the dissolved Cr was present as Cr(VI), which was different from that for the urban aerosol. It is suggested that the increased adverse health effects of aerosol particles in metros with respect to ambient outdoor particles is linked to the differences in the oxidation states, surface properties or morphologies.

Original languageEnglish
Pages (from-to)3460-3466
Number of pages7
JournalAtmospheric Environment
Volume43
Issue number22-23
DOIs
Publication statusPublished - Jul 2009

Fingerprint

Particles (particulate matter)
Aerosols
aerosol
Hematite
hematite
Iron oxides
iron oxide
Bearings (structural)
spectroscopy
Chemical speciation
Spectroscopy
oxidation
electron
Oxidation
ferrite
speciation (chemistry)
atomic force microscopy
Magnetite
Debris
Electron diffraction

Keywords

  • Chromium
  • Health effects
  • Hematite
  • Individual particles
  • Iron
  • Speciation
  • Surface properties
  • Underground railways

ASJC Scopus subject areas

  • Atmospheric Science
  • Environmental Science(all)

Cite this

@article{990991617ac54a89a5e6488bcae5d941,
title = "Properties and sources of individual particles and some chemical species in the aerosol of a metropolitan underground railway station",
abstract = "Aerosol samples in PM10-2.0 and PM2.0 size fractions were collected on the platform of a metropolitan underground railway station in central Budapest. Individual aerosol particles were studied using atomic force microscopy, scanning electron microscopy and transmission electron microscopy with energy-dispersive X-ray spectrometry and electron diffraction. The bulk aerosol samples were investigated by 57Fe M{\"o}ssbauer spectroscopy, and they were subjected to chemical speciation analysis for Cr. The particles were classified into groups of iron oxides and iron, carbonates, silicates, quartz and carbonaceous debris. Electron micrographs showed that the Fe-rich particles in the PM2.0 size fraction typically consisted of aggregates of nano-sized hematite crystals that were randomly oriented, had round shapes and diameters of 5-15 nm. In addition to hematite, a minor fraction of the iron oxide particles also contained magnetite. In addition, the PM2.0-fraction particles typically had a rugged surface with layered or granular morphologies. M{\"o}ssbauer spectroscopy suggested that hematite was a major Fe-bearing species in the PM10-2.0 size fraction; its mass contribution to the Fe was 36{\%}. Further constituents (ferrite, carbides and FeOOH) were also identified. The water soluble amounts of Cr for the underground railway station and city center were similar. In the PM10-2.0 size fraction, practically all dissolved Cr had an oxidation state of three, which corresponds to ambient conditions. In the PM2.0 size fraction, however, approximately 7{\%} of the dissolved Cr was present as Cr(VI), which was different from that for the urban aerosol. It is suggested that the increased adverse health effects of aerosol particles in metros with respect to ambient outdoor particles is linked to the differences in the oxidation states, surface properties or morphologies.",
keywords = "Chromium, Health effects, Hematite, Individual particles, Iron, Speciation, Surface properties, Underground railways",
author = "I. Salma and M. P{\'o}sfai and Krist{\'o}f Kov{\'a}cs and E. Kuzmann and Z. Homonnay and J. Posta",
year = "2009",
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doi = "10.1016/j.atmosenv.2009.04.042",
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T1 - Properties and sources of individual particles and some chemical species in the aerosol of a metropolitan underground railway station

AU - Salma, I.

AU - Pósfai, M.

AU - Kovács, Kristóf

AU - Kuzmann, E.

AU - Homonnay, Z.

AU - Posta, J.

PY - 2009/7

Y1 - 2009/7

N2 - Aerosol samples in PM10-2.0 and PM2.0 size fractions were collected on the platform of a metropolitan underground railway station in central Budapest. Individual aerosol particles were studied using atomic force microscopy, scanning electron microscopy and transmission electron microscopy with energy-dispersive X-ray spectrometry and electron diffraction. The bulk aerosol samples were investigated by 57Fe Mössbauer spectroscopy, and they were subjected to chemical speciation analysis for Cr. The particles were classified into groups of iron oxides and iron, carbonates, silicates, quartz and carbonaceous debris. Electron micrographs showed that the Fe-rich particles in the PM2.0 size fraction typically consisted of aggregates of nano-sized hematite crystals that were randomly oriented, had round shapes and diameters of 5-15 nm. In addition to hematite, a minor fraction of the iron oxide particles also contained magnetite. In addition, the PM2.0-fraction particles typically had a rugged surface with layered or granular morphologies. Mössbauer spectroscopy suggested that hematite was a major Fe-bearing species in the PM10-2.0 size fraction; its mass contribution to the Fe was 36%. Further constituents (ferrite, carbides and FeOOH) were also identified. The water soluble amounts of Cr for the underground railway station and city center were similar. In the PM10-2.0 size fraction, practically all dissolved Cr had an oxidation state of three, which corresponds to ambient conditions. In the PM2.0 size fraction, however, approximately 7% of the dissolved Cr was present as Cr(VI), which was different from that for the urban aerosol. It is suggested that the increased adverse health effects of aerosol particles in metros with respect to ambient outdoor particles is linked to the differences in the oxidation states, surface properties or morphologies.

AB - Aerosol samples in PM10-2.0 and PM2.0 size fractions were collected on the platform of a metropolitan underground railway station in central Budapest. Individual aerosol particles were studied using atomic force microscopy, scanning electron microscopy and transmission electron microscopy with energy-dispersive X-ray spectrometry and electron diffraction. The bulk aerosol samples were investigated by 57Fe Mössbauer spectroscopy, and they were subjected to chemical speciation analysis for Cr. The particles were classified into groups of iron oxides and iron, carbonates, silicates, quartz and carbonaceous debris. Electron micrographs showed that the Fe-rich particles in the PM2.0 size fraction typically consisted of aggregates of nano-sized hematite crystals that were randomly oriented, had round shapes and diameters of 5-15 nm. In addition to hematite, a minor fraction of the iron oxide particles also contained magnetite. In addition, the PM2.0-fraction particles typically had a rugged surface with layered or granular morphologies. Mössbauer spectroscopy suggested that hematite was a major Fe-bearing species in the PM10-2.0 size fraction; its mass contribution to the Fe was 36%. Further constituents (ferrite, carbides and FeOOH) were also identified. The water soluble amounts of Cr for the underground railway station and city center were similar. In the PM10-2.0 size fraction, practically all dissolved Cr had an oxidation state of three, which corresponds to ambient conditions. In the PM2.0 size fraction, however, approximately 7% of the dissolved Cr was present as Cr(VI), which was different from that for the urban aerosol. It is suggested that the increased adverse health effects of aerosol particles in metros with respect to ambient outdoor particles is linked to the differences in the oxidation states, surface properties or morphologies.

KW - Chromium

KW - Health effects

KW - Hematite

KW - Individual particles

KW - Iron

KW - Speciation

KW - Surface properties

KW - Underground railways

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DO - 10.1016/j.atmosenv.2009.04.042

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JO - Atmospheric Environment

JF - Atmospheric Environment

SN - 1352-2310

IS - 22-23

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