Laboratory Study of Simulated Atmospheric Transformations of Chromium in Ultrafine Combustion Aerosol Particles

Michelle Werner, Peter Nico, Bing Guo, Ian Kennedy, Cort Anastasio

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

While atmospheric particles can have adverse health effects, the reasons for this toxicity are largely unclear. One possible reason is that the particles can contain toxic metals such as chromium. Chromium exists in the environment in two major oxidation states: III, which is an essential nutrient, and VI, which is highly toxic and carcinogenic. Currently little is known about the speciation of chromium in airborne particles or how this speciation is altered by atmospheric reactions. To investigate the potential impacts of atmospheric aging on the speciation and toxicity of chromium-containing particles, we collected chromium and chromium-iron combustion ultrafine particles on Teflon filters and exposed the particles to a combination of light, ozone, water vapor, and, in some cases, basic or acidic conditions. After the aging process, the aged and not-aged samples were analyzed for Cr oxidation state using X-ray Absorption Near Edge Spectroscopy (XANES). We found that the aging process reduced Cr(VI) by as much as 20% in chromium particles that had high initial Cr(VI)/Cr(total) ratios. This reduction of Cr(VI) to Cr(III) appears to be due to reactions primarily with light and hydroperoxyl radical (HO2) in the chamber. Particles that had low initial Cr(VI)/Cr(total) ratios experienced no significant change in Cr oxidation states after aging. Compared to particles containing only Cr, the addition of Fe to the flame decreased the Cr(VI)/Cr(total) ratio in fresh Cr-Fe particles by ∼60%. Aging of these Cr-Fe particles had no additional effects on the Cr(VI)/Cr(total) ratio.

Original languageEnglish
Pages (from-to)545-556
Number of pages12
JournalAerosol Science and Technology
Volume40
Issue number7
DOIs
Publication statusPublished - 1 Jul 2006
Externally publishedYes

Fingerprint

Chromium
Aerosols
Particles (particulate matter)
chromium
combustion
aerosol
Aging of materials
Poisons
Oxidation
Toxicity
oxidation
Ozone
Steam
X ray absorption
Polytetrafluoroethylene
Ultrafine
laboratory
particle
Polytetrafluoroethylenes
toxicity

ASJC Scopus subject areas

  • Environmental Chemistry
  • Materials Science(all)
  • Pollution

Cite this

Laboratory Study of Simulated Atmospheric Transformations of Chromium in Ultrafine Combustion Aerosol Particles. / Werner, Michelle; Nico, Peter; Guo, Bing; Kennedy, Ian; Anastasio, Cort.

In: Aerosol Science and Technology, Vol. 40, No. 7, 01.07.2006, p. 545-556.

Research output: Contribution to journalArticle

Werner, Michelle ; Nico, Peter ; Guo, Bing ; Kennedy, Ian ; Anastasio, Cort. / Laboratory Study of Simulated Atmospheric Transformations of Chromium in Ultrafine Combustion Aerosol Particles. In: Aerosol Science and Technology. 2006 ; Vol. 40, No. 7. pp. 545-556.
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