ROS-generation potential of Humic-like substances (HULIS) in ambient PM2.5 in urban Shanghai: Association with HULIS concentration and light absorbance

Xiaoya Xu; Xiaohui Lu; Xiang Li; Yaxi Liu; Xiaofei Wang; Hong Chen; Jianmin Chen; Xin Yang; Tzung-May Fu; Qianbiao Zhao; Qingyan Fu

doi:10.1016/j.chemosphere.2020.127050

ROS-generation potential of Humic-like substances (HULIS) in ambient PM_2.5 in urban Shanghai: Association with HULIS concentration and light absorbance

Chemosphere. 2020 Oct:256:127050. doi: 10.1016/j.chemosphere.2020.127050. Epub 2020 May 13.

Authors

Xiaoya Xu¹, Xiaohui Lu², Xiang Li¹, Yaxi Liu¹, Xiaofei Wang¹, Hong Chen¹, Jianmin Chen¹, Xin Yang³, Tzung-May Fu⁴, Qianbiao Zhao⁵, Qingyan Fu⁶

Affiliations

¹ Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China.
² Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China. Electronic address: luxiaohui@fudan.edu.cn.
³ Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China. Electronic address: yangxin@fudan.edu.cn.
⁴ School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong Province, China.
⁵ Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China; Shanghai Environmental Monitoring Center, Shanghai, 200235, China.
⁶ Shanghai Environmental Monitoring Center, Shanghai, 200235, China.

PMID: 32446002
DOI: 10.1016/j.chemosphere.2020.127050

Abstract

Ambient fine particulate matter (PM_2.5) can cause adverse health effects through the generation of reactive oxygen species (ROS) after inhalation. Humic-like substances (HULIS) are major constituents contributing to the ROS-generation potential in organic aerosols. In this study, PM_2.5 samples in urban Shanghai during autumn and winter (2018-2019) were collected. Mass-normalized ·OH generation rate in surrogate lung fluid (SLF) was used to denote the intrinsic ROS-generation potential of PM_2.5 or of the HULIS isolated from PM_2.5. In this study, ROS-generation potential of PM_2.5 decreased with increasing ambient PM_2.5 concentration due to higher percentage of inorganic components in high PM_2.5 event. Same trend was observed for the ROS-generation potential of unit mass of HULIS, which was higher when HULIS and PM_2.5 concentrations were both relatively lower. The HULIS with high ROS-generation potential but low concentration (High-ROS/Low-Conc HULIS) were likely produced by the atmospheric aqueous-phase reactions during nighttime or under high relative humidity conditions, not from biomass burning emissions or the photochemical pollution products. The association between ROS-generation potential and light absorption properties of HULIS was studied as well. The High-ROS/Low-Conc HULIS also showed stronger light absorbance than the other HULIS. Our results implied the potentially important roles that HULIS species might play in atmospheric environment and human health even when the PM_2.5 pollution is low.

Keywords: Humic-like substances (HULIS); Light absorbance; PM(2.5); Reactive oxygen species (ROS); Surrogate lung fluid (SLF).

MeSH terms

Aerosols / analysis
Air Pollutants / analysis*
China
Environmental Monitoring
Humic Substances / analysis*
Particulate Matter / analysis*
Reactive Oxygen Species / chemistry*
Seasons
Water / chemistry

Substances

Aerosols
Air Pollutants
Humic Substances
Particulate Matter
Reactive Oxygen Species
Water