Characteristics and toxicological effects of commuter exposure to black carbon and metal components of fine particles (PM2.5) in Hong Kong

Xiao Cui Chen; Jun Ji Cao; Tony J. Ward; Lin Wei Tian; Zhi Ning; Nirmal Kumar Gali; Noel J. Aquilina; Steve Hung Lam Yim; Linli Qu; Kin Fai Ho

doi:10.1016/j.scitotenv.2020.140501

Characteristics and toxicological effects of commuter exposure to black carbon and metal components of fine particles (PM_2.5) in Hong Kong

Xiao Cui Chen
, Jun Ji Cao
, Tony J. Ward
, Lin Wei Tian
, Zhi Ning
, Nirmal Kumar Gali
, Noel J. Aquilina
, Steve Hung Lam Yim
, Linli Qu
, Kin Fai Ho

Research output: Contribution to journal › Article › peer-review

47 Scopus citations

Abstract

Epidemiological studies have demonstrated significant associations between traffic-related air pollution and adverse health outcomes. Personal exposure to fine particles (PM_2.5) in transport microenvironments and their toxicological properties remain to be investigated. Commuter exposures were investigated in public transport systems (including the buses and Mass Transit Railway (MTR)) along two sampling routes in Hong Kong. Real-time sampling for PM_2.5 and black carbon (BC), along with integrated PM_2.5 sampling, were performed during the warm and cold season of 2016–2017, respectively. Commuter exposure to BC during 3-hour commuting time exhibited a wider range, from 3.4 to 4.6 μg/m³ on the bus and 5.5 to 8.7 μg/m³ in MTR cabin (p <.05). PM_2.5 mass and major chemical constituents (including organic carbon (OC), elemental carbon (EC), and metals) were analyzed. Cytotoxicity, including cellular reactive oxygen species (ROS) production, was determined in addition to acellular ROS generation. PM_2.5 treatment promoted the ROS generation in a concentration-dependent manner. Consistent diurnal variations were observed for commuter exposure to BC and PM_2.5 components, along with cellular and acellular ROS generation, which marked with two peaks during the morning (08:00–11:00) and evening rush hours (17:30–20:30). Commuter exposures in the MTR system were characterized by higher levels of PM_2.5 and elemental components (e.g., Ca, Cr, Fe, Zn, Ba) compared to riding the bus, along with higher cellular and acellular ROS production (p <.01). These metals were attributed to different sources: rail tracks, wheels, brakes, and crustal origin. Weak to moderate associations were shown for the analyzed transition metals with PM_2.5-induced cell viability and cellular ROS. Multiple linear regression analysis revealed that Ni, Zn, Mn, Fe, Ti, and Co attributed to cytotoxicity and ROS generation. These findings underscore the importance of commuter exposures and their toxic effects, urging effective mitigating strategies to protect human health.

Original language	English
Article number	140501
Journal	Science of the Total Environment
Volume	742
DOIs	https://doi.org/10.1016/j.scitotenv.2020.140501
State	Published - Nov 10 2020

Funding

This work was supported by the grants from the Research Grants Council of The Hong Kong Special Administrative Region of China [grant numbers 14202817 , 14212116 , 412413 ]. Xiao-Cui Chen acknowledges the National Natural Science Foundation of China [grant number 41907181 ]. The authors acknowledge the help with transport measurements from research assistants and student helpers. Dr. Lei-Lei Fei from South China Institute of Environmental Sciences provided valuable technical support.

Funders	Funder number
14202817, 412413, 14212116
National Natural Science Foundation of China	41907181

Keywords

Black carbon
Commuter exposure
Cytotoxicity
Reactive oxygen species (ROS)
Transition metals

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

Access to Document

10.1016/j.scitotenv.2020.140501

Cite this

Chen, X. C., Cao, J. J., Ward, T. J., Tian, L. W., Ning, Z., Gali, N. K., Aquilina, N. J., Yim, S. H. L., Qu, L., & Ho, K. F. (2020). Characteristics and toxicological effects of commuter exposure to black carbon and metal components of fine particles (PM_2.5) in Hong Kong. Science of the Total Environment, 742, Article 140501. https://doi.org/10.1016/j.scitotenv.2020.140501

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abstract = "Epidemiological studies have demonstrated significant associations between traffic-related air pollution and adverse health outcomes. Personal exposure to fine particles (PM2.5) in transport microenvironments and their toxicological properties remain to be investigated. Commuter exposures were investigated in public transport systems (including the buses and Mass Transit Railway (MTR)) along two sampling routes in Hong Kong. Real-time sampling for PM2.5 and black carbon (BC), along with integrated PM2.5 sampling, were performed during the warm and cold season of 2016–2017, respectively. Commuter exposure to BC during 3-hour commuting time exhibited a wider range, from 3.4 to 4.6 μg/m3 on the bus and 5.5 to 8.7 μg/m3 in MTR cabin (p <.05). PM2.5 mass and major chemical constituents (including organic carbon (OC), elemental carbon (EC), and metals) were analyzed. Cytotoxicity, including cellular reactive oxygen species (ROS) production, was determined in addition to acellular ROS generation. PM2.5 treatment promoted the ROS generation in a concentration-dependent manner. Consistent diurnal variations were observed for commuter exposure to BC and PM2.5 components, along with cellular and acellular ROS generation, which marked with two peaks during the morning (08:00–11:00) and evening rush hours (17:30–20:30). Commuter exposures in the MTR system were characterized by higher levels of PM2.5 and elemental components (e.g., Ca, Cr, Fe, Zn, Ba) compared to riding the bus, along with higher cellular and acellular ROS production (p <.01). These metals were attributed to different sources: rail tracks, wheels, brakes, and crustal origin. Weak to moderate associations were shown for the analyzed transition metals with PM2.5-induced cell viability and cellular ROS. Multiple linear regression analysis revealed that Ni, Zn, Mn, Fe, Ti, and Co attributed to cytotoxicity and ROS generation. These findings underscore the importance of commuter exposures and their toxic effects, urging effective mitigating strategies to protect human health.",

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author = "Chen, \{Xiao Cui\} and Cao, \{Jun Ji\} and Ward, \{Tony J.\} and Tian, \{Lin Wei\} and Zhi Ning and Gali, \{Nirmal Kumar\} and Aquilina, \{Noel J.\} and Yim, \{Steve Hung Lam\} and Linli Qu and Ho, \{Kin Fai\}",

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T1 - Characteristics and toxicological effects of commuter exposure to black carbon and metal components of fine particles (PM2.5) in Hong Kong

AU - Chen, Xiao Cui

AU - Cao, Jun Ji

AU - Ward, Tony J.

AU - Tian, Lin Wei

AU - Ning, Zhi

AU - Gali, Nirmal Kumar

AU - Aquilina, Noel J.

AU - Yim, Steve Hung Lam

AU - Qu, Linli

AU - Ho, Kin Fai

PY - 2020/11/10

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N2 - Epidemiological studies have demonstrated significant associations between traffic-related air pollution and adverse health outcomes. Personal exposure to fine particles (PM2.5) in transport microenvironments and their toxicological properties remain to be investigated. Commuter exposures were investigated in public transport systems (including the buses and Mass Transit Railway (MTR)) along two sampling routes in Hong Kong. Real-time sampling for PM2.5 and black carbon (BC), along with integrated PM2.5 sampling, were performed during the warm and cold season of 2016–2017, respectively. Commuter exposure to BC during 3-hour commuting time exhibited a wider range, from 3.4 to 4.6 μg/m3 on the bus and 5.5 to 8.7 μg/m3 in MTR cabin (p <.05). PM2.5 mass and major chemical constituents (including organic carbon (OC), elemental carbon (EC), and metals) were analyzed. Cytotoxicity, including cellular reactive oxygen species (ROS) production, was determined in addition to acellular ROS generation. PM2.5 treatment promoted the ROS generation in a concentration-dependent manner. Consistent diurnal variations were observed for commuter exposure to BC and PM2.5 components, along with cellular and acellular ROS generation, which marked with two peaks during the morning (08:00–11:00) and evening rush hours (17:30–20:30). Commuter exposures in the MTR system were characterized by higher levels of PM2.5 and elemental components (e.g., Ca, Cr, Fe, Zn, Ba) compared to riding the bus, along with higher cellular and acellular ROS production (p <.01). These metals were attributed to different sources: rail tracks, wheels, brakes, and crustal origin. Weak to moderate associations were shown for the analyzed transition metals with PM2.5-induced cell viability and cellular ROS. Multiple linear regression analysis revealed that Ni, Zn, Mn, Fe, Ti, and Co attributed to cytotoxicity and ROS generation. These findings underscore the importance of commuter exposures and their toxic effects, urging effective mitigating strategies to protect human health.

AB - Epidemiological studies have demonstrated significant associations between traffic-related air pollution and adverse health outcomes. Personal exposure to fine particles (PM2.5) in transport microenvironments and their toxicological properties remain to be investigated. Commuter exposures were investigated in public transport systems (including the buses and Mass Transit Railway (MTR)) along two sampling routes in Hong Kong. Real-time sampling for PM2.5 and black carbon (BC), along with integrated PM2.5 sampling, were performed during the warm and cold season of 2016–2017, respectively. Commuter exposure to BC during 3-hour commuting time exhibited a wider range, from 3.4 to 4.6 μg/m3 on the bus and 5.5 to 8.7 μg/m3 in MTR cabin (p <.05). PM2.5 mass and major chemical constituents (including organic carbon (OC), elemental carbon (EC), and metals) were analyzed. Cytotoxicity, including cellular reactive oxygen species (ROS) production, was determined in addition to acellular ROS generation. PM2.5 treatment promoted the ROS generation in a concentration-dependent manner. Consistent diurnal variations were observed for commuter exposure to BC and PM2.5 components, along with cellular and acellular ROS generation, which marked with two peaks during the morning (08:00–11:00) and evening rush hours (17:30–20:30). Commuter exposures in the MTR system were characterized by higher levels of PM2.5 and elemental components (e.g., Ca, Cr, Fe, Zn, Ba) compared to riding the bus, along with higher cellular and acellular ROS production (p <.01). These metals were attributed to different sources: rail tracks, wheels, brakes, and crustal origin. Weak to moderate associations were shown for the analyzed transition metals with PM2.5-induced cell viability and cellular ROS. Multiple linear regression analysis revealed that Ni, Zn, Mn, Fe, Ti, and Co attributed to cytotoxicity and ROS generation. These findings underscore the importance of commuter exposures and their toxic effects, urging effective mitigating strategies to protect human health.

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