Inflammatory and oxidative stress responses of healthy elders to solar-assisted large-scale cleaning system (SALSCS) and changes in ambient air pollution: A quasi-interventional study in Xi'an, China

Hong Qiu; Xin-Yi Niu; Jun-Ji Cao; Hong-Mei Xu; Shun Xiao; Ning-Ning Zhang; Xi Xia; Zhen-Xing Shen; Yu Huang; Gabriel Ngar-Cheung Lau; Steve Hung-Lam Yim; Kin-Fai Ho

doi:10.1016/j.scitotenv.2021.151217

Inflammatory and oxidative stress responses of healthy elders to solar-assisted large-scale cleaning system (SALSCS) and changes in ambient air pollution: A quasi-interventional study in Xi'an, China

Sci Total Environ. 2022 Feb 1;806(Pt 3):151217. doi: 10.1016/j.scitotenv.2021.151217. Epub 2021 Oct 27.

Authors

Hong Qiu¹, Xin-Yi Niu², Jun-Ji Cao³, Hong-Mei Xu⁴, Shun Xiao⁵, Ning-Ning Zhang⁶, Xi Xia⁷, Zhen-Xing Shen⁴, Yu Huang⁸, Gabriel Ngar-Cheung Lau⁹, Steve Hung-Lam Yim¹⁰, Kin-Fai Ho¹¹

Affiliations

¹ Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, HKSAR, China.
² School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, China; The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, HKSAR, China.
³ Key Lab of Aerosol Chemistry & Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China; State Key Lab of Loess and Quaternary Geology (SKLLQG), Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China. Electronic address: cao@loess.llqg.ac.cn.
⁴ Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an, China.
⁵ School of Geography and Tourism, Shaanxi Normal University, Xi'an, China.
⁶ Key Lab of Aerosol Chemistry & Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China.
⁷ The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, HKSAR, China.
⁸ Key Lab of Aerosol Chemistry & Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China; State Key Lab of Loess and Quaternary Geology (SKLLQG), Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China.
⁹ Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, HKSAR, China; Department of Geography and Resource Management, The Chinese University of Hong Kong, HKSAR, China.
¹⁰ Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, HKSAR, China; Department of Geography and Resource Management, The Chinese University of Hong Kong, HKSAR, China; The Asian School of the Environment, Nanyang Technological University, Singapore.
¹¹ Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, HKSAR, China; The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, HKSAR, China. Electronic address: kfho@cuhk.edu.hk.

PMID: 34717999
DOI: 10.1016/j.scitotenv.2021.151217

Abstract

An outdoor solar assisted large-scale cleaning system (SALSCS) was constructed to mitigate the levels of fine particulate matter (PM_2.5) in urban areas of Xi'an China, providing a quasi-experimental opportunity to examine the biologic responses to the changes in pollution level. We conducted this outdoor SALSCS based real-world quasi-interventional study to examine the associations of the SALSCS intervention and changes in air pollution levels with the biomarkers of systemic inflammation and oxidative stress in healthy elders. We measured the levels of 8-hydrox-2-deoxyguanosine (8-OHdG), Interlukin-6 (IL-6), as well as tumor necrosis factor alpha (TNF-α) from urine samples, and IL-6 from saliva samples of 123 healthy retired participants from interventional/control residential areas in two sampling campaigns. We collected daily 24-h PM_2.5 samples in two residential areas during the study periods using mini-volume samplers. Data on PM₁₀, gaseous pollutants and weather factors were collected from the nearest national air quality monitoring stations. We used linear mixed-effect models to examine the percent change in each biomarker associated with the SALSCS intervention and air pollution levels, after adjusting for time trend, seasonality, weather factors and personal characteristics. Results showed that the SALSCS intervention was significantly associated with decreases in the geometric mean of biomarkers by 47.6% (95% confidence interval: 16.5-67.2%) for 8-OHdG, 66% (31.0-83.3%) for TNF-α, 41.7% (0.2-65.9%) and 43.4% (13.6-62.9%) for urinary and salivary IL-6, respectively. An inter-quartile range increase of ambient PM_2.5 exposure averaged on the day of the collection of bio-samples and the day before (34.1 μg/m³) was associated, albeit non-significantly so, with 22.8%-37.9% increases in the geometric mean of these biomarkers. This study demonstrated that the SALSCS intervention and decreased ambient air pollution exposure results in lower burden of systemic inflammation and oxidative stress in older adults.

Keywords: Biomarker; Inflammation; Oxidative stress; Quasi-interventional study; Solar-assisted large-scale cleaning system.

MeSH terms

Aged
Air Pollutants* / analysis
Air Pollution* / analysis
China
Environmental Pollution
Humans
Oxidative Stress
Particulate Matter / analysis

Substances

Air Pollutants
Particulate Matter