Linking molecular composition of organic aerosols to reactive oxygen species formation using an MCR-VK framework
- 1China Agricultural University (Beijing, China)
- 2Helmholtz-Zentrum Hereon (Geesthacht, Germany)
- 3Max Planck Institute for Chemistry (Mainz, Germany)
Abstract
Reactive oxygen species (ROS) formation by atmospheric fine particulate matter (PM) is widely implicated in adverse health effects, yet the molecular determinants of particle-level ROS formation remain poorly constrained, largely due to the chemical complexity of organic aerosol (OA). Here, we link ROS formation to molecular-level OA composition by applying a maximum carbonyl ratio-Van Krevelen framework to ambient fine PM collected from four Chinese megacities, a German semi-urban site, a boreal forest, and laboratory-generated secondary organic aerosol (SOA) from multiple precursors. Using ultrahigh-resolution mass spectrometry combined with hydrogen peroxide (H ₂ O ₂ ) and radical measurements, we show the intrinsic ROS (H ₂ O ₂ + radicals) formation potential of fine PM is governed by OA composition rather than particle mass. Volume-normalized ROS yields increase with fine PM mass concentration and dominate overall exposure in polluted urban environments. In contrast, mass-normalized ROS yields vary independently of particle loading and are strongly driven by the balance between relative fractions of oxidized organic compounds (RF OOC ) and unsaturated organic compounds (RF UOC ), i.e., RF OOC / RF UOC . Across urban sites, mass-normalized ROS and H ₂ O ₂ yields exhibit strong correlations with RF OOC / RF UOC , establishing this metric as a robust predictor of ROS formation. Remote, biogenic-influenced aerosols exhibit higher RF OOC / RF UOC and higher ROS yields per unit mass, whereas urban aerosols exhibit the opposite behavior. Laboratory SOA further supports these composition-reactivity relationships, with OOC-rich biogenic SOA exhibiting the highest ROS yields. This study reveals molecular-level characteristics in governing aerosol ROS formation and introduces a framework for assessing health-relevant aerosol oxidative activity of chemically complex OA.
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BibTeX
@article{liu2026linking,
title = {{Linking molecular composition of organic aerosols to reactive oxygen species formation using an MCR-VK framework}},
author = {Fobang Liu and Yun Zhang and Siyao Yue and Helmi-Marja K. Keskinen and Tuukka Petäjä and Markku Kulmala and Pingqing Fu and Thorsten Hoffmann and Kai Wang and Haijie Tong},
journal = {Atmospheric Chemistry and Physics},
year = {2026},
month = oct,
doi = {10.5194/acp-26-14655-2026},
url = {https://acp.copernicus.org/articles/26/14655/2026/},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Linking molecular composition of organic aerosols to reactive oxygen species formation using an MCR-VK framework
AU - Fobang Liu
AU - Yun Zhang
AU - Siyao Yue
AU - Helmi-Marja K. Keskinen
AU - Tuukka Petäjä
AU - Markku Kulmala
AU - Pingqing Fu
AU - Thorsten Hoffmann
AU - Kai Wang
AU - Haijie Tong
PY - 2026
DA - 2026/10/16
JO - Atmospheric Chemistry and Physics
DO - 10.5194/acp-26-14655-2026
UR - https://acp.copernicus.org/articles/26/14655/2026/
AB - Reactive oxygen species (ROS) formation by atmospheric fine particulate matter (PM) is widely implicated in adverse health effects, yet the molecular determinants of particle-level ROS formation remain poorly constrained, largely due to the chemical complexity of organic aerosol (OA). Here, we link ROS formation to molecular-level OA composition by applying a maximum carbonyl ratio-Van Krevelen framework to ambient fine PM collected from four Chinese megacities, a German semi-urban site, a boreal forest, and laboratory-generated secondary organic aerosol (SOA) from multiple precursors. Using ultrahigh-resolution mass spectrometry combined with hydrogen peroxide (H ₂ O ₂ ) and radical measurements, we show the intrinsic ROS (H ₂ O ₂ + radicals) formation potential of fine PM is governed by OA composition rather than particle mass. Volume-normalized ROS yields increase with fine PM mass concentration and dominate overall exposure in polluted urban environments. In contrast, mass-normalized ROS yields vary independently of particle loading and are strongly driven by the balance between relative fractions of oxidized organic compounds (RF OOC ) and unsaturated organic compounds (RF UOC ), i.e., RF OOC / RF UOC . Across urban sites, mass-normalized ROS and H ₂ O ₂ yields exhibit strong correlations with RF OOC / RF UOC , establishing this metric as a robust predictor of ROS formation. Remote, biogenic-influenced aerosols exhibit higher RF OOC / RF UOC and higher ROS yields per unit mass, whereas urban aerosols exhibit the opposite behavior. Laboratory SOA further supports these composition-reactivity relationships, with OOC-rich biogenic SOA exhibiting the highest ROS yields. This study reveals molecular-level characteristics in governing aerosol ROS formation and introduces a framework for assessing health-relevant aerosol oxidative activity of chemically complex OA.
SN - 1680-7324
ER -