TY - JOUR
T1 - Quantification of environmentally persistent free radicals and reactive oxygen species in atmospheric aerosol particles
AU - Arangio, Andrea M.
AU - Tong, Haijie
AU - Socorro, Joanna
AU - Pöschl, Ulrich
AU - Shiraiwa, Manabu
N1 - Publisher Copyright:
© Author(s) 2016. CC Attribution 3.0 License.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2016/10/26
Y1 - 2016/10/26
N2 - Fine particulate matter plays a central role in the adverse health effects of air pollution. Inhalation and deposition of aerosol particles in the respiratory tract can lead to the release of reactive oxygen species (ROS), which may cause oxidative stress. In this study, we have detected and quantified a wide range of particle-associated radicals using electron paramagnetic resonance (EPR) spectroscopy. Ambient particle samples were collected using a cascade impactor at a semi-urban site in central Europe, Mainz, Germany, in May-June 2015. Concentrations of environmentally persistent free radicals (EPFR), most likely semiquinone radicals, were found to be in the range of (1-7) ×1011 spins μg-1 for particles in the accumulation mode, whereas coarse particles with a diameter larger than 1 μm did not contain substantial amounts of EPFR. Using a spin trapping technique followed by deconvolution of EPR spectra, we have also characterized and quantified ROS, including OH, superoxide (O2-/ and carbon- and oxygen-centered organic radicals, which were formed upon extraction of the particle samples in water. Total ROS amounts of (0.1-3)×1011 spins μg-1 were released by submicron particle samples and the relative contributions of OH, O2-, C-centered and O-centered organic radicals were ∼11-31, ∼2-8, ∼41-72 and ∼0-25 %, respectively, depending on particle sizes. OH was the dominant species for coarse particles. Based on comparisons of the EPR spectra of ambient particulate matter with those of mixtures of organic hydroperoxides, quinones and iron ions followed by chemical analysis using liquid chromatography mass spectrometry (LC-MS), we suggest that the particle-associated ROS were formed by decomposition of organic hydroperoxides interacting with transition metal ions and quinones contained in atmospheric humic-like substances (HULIS).
AB - Fine particulate matter plays a central role in the adverse health effects of air pollution. Inhalation and deposition of aerosol particles in the respiratory tract can lead to the release of reactive oxygen species (ROS), which may cause oxidative stress. In this study, we have detected and quantified a wide range of particle-associated radicals using electron paramagnetic resonance (EPR) spectroscopy. Ambient particle samples were collected using a cascade impactor at a semi-urban site in central Europe, Mainz, Germany, in May-June 2015. Concentrations of environmentally persistent free radicals (EPFR), most likely semiquinone radicals, were found to be in the range of (1-7) ×1011 spins μg-1 for particles in the accumulation mode, whereas coarse particles with a diameter larger than 1 μm did not contain substantial amounts of EPFR. Using a spin trapping technique followed by deconvolution of EPR spectra, we have also characterized and quantified ROS, including OH, superoxide (O2-/ and carbon- and oxygen-centered organic radicals, which were formed upon extraction of the particle samples in water. Total ROS amounts of (0.1-3)×1011 spins μg-1 were released by submicron particle samples and the relative contributions of OH, O2-, C-centered and O-centered organic radicals were ∼11-31, ∼2-8, ∼41-72 and ∼0-25 %, respectively, depending on particle sizes. OH was the dominant species for coarse particles. Based on comparisons of the EPR spectra of ambient particulate matter with those of mixtures of organic hydroperoxides, quinones and iron ions followed by chemical analysis using liquid chromatography mass spectrometry (LC-MS), we suggest that the particle-associated ROS were formed by decomposition of organic hydroperoxides interacting with transition metal ions and quinones contained in atmospheric humic-like substances (HULIS).
UR - http://www.scopus.com/inward/record.url?scp=84992695117&partnerID=8YFLogxK
U2 - 10.5194/acp-16-13105-2016
DO - 10.5194/acp-16-13105-2016
M3 - Journal article
AN - SCOPUS:84992695117
SN - 1680-7316
VL - 16
SP - 13105
EP - 13119
JO - Atmospheric Chemistry and Physics
JF - Atmospheric Chemistry and Physics
IS - 20
ER -