Vertical Characteristics of Potential PM2.5 Sources in the Urban Environment

Ho‐Tang Liao; Yu‐Chi Lai; Hsing Jasmine Chao; Chang‐Fu Wu

doi:10.4209/aaqr.220361

Vertical Characteristics of Potential PM2.5 Sources in the Urban Environment

Special Issue on 2022 Asian Aerosol Conference (AAC 2022)

Ho‐Tang Liao¹, Yu‐Chi Lai¹, Hsing Jasmine Chao², Chang‐Fu Wu This email address is being protected from spambots. You need JavaScript enabled to view it.^1,3

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¹Institute of Environmental and Occupational Health Sciences, College of Public Health, National Taiwan University, Taipei 10055, Taiwan
²School of Public Health, College of Public Health, Taipei Medical University, Taipei 11031, Taiwan
³Department of Public Health, College of Public Health, National Taiwan University, Taipei 10055, Taiwan

Received: October 25, 2022
Revised: December 27, 2022
Accepted: January 3, 2023

Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

Download Citation: ||https://doi.org/10.4209/aaqr.220361

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Cite this article:

Liao, H.T., Lai, Y.C., Chao, H.J., Wu, C.F. (2023). Vertical Characteristics of Potential PM_2.5 Sources in the Urban Environment. Aerosol Air Qual. Res. https://doi.org/10.4209/aaqr.220361

HIGHLIGHTS

PM_2.5 mass concentrations generally declined with height.
The largest contributor (secondary aerosol, 28.8%) to PM_2.5 increased with height.
The second one was road traffic (traffic related and contaminated road dust, 24.7%).
Contributions of road traffic emissions significantly declined with height.
Our findings indicated significant contributions from local ground-level emissions.

ABSTRACT

Exposure to urban air pollution, particularly fine particulate matter (PM_2.5), is known to be harmful to human health. Source apportionment of urban PM_2.5 provides information to develop effective control strategies, thus reducing the exposure concentrations and health risks. However, this is a challenging task in metropolitan areas where people live in high‐rise buildings. To understand the vertical characteristics of air pollution sources in urban areas, a total of 114 vertically stratified PM_2.5 samples were collected at six heights (1^st, 7^th, 10^th, 13^th, 17^th, and 20^thfloors) of one building during the period between 19 October and 22 December 2020. Absorbance, 16 trace elements, 8 water‐soluble ions, and water‐soluble organic carbon on Teflon‐membrane filters were measured. Positive Matrix Factorization was utilized to achieve the source apportionment analysis. Six source factors, including biomass burning/industry, traffic related, secondary aerosol, soil dust, contaminated road dust, and sea salt, were retrieved. During the sampling period, the major contributor to PM_2.5 was secondary aerosol (28.8%), followed by biomass burning/industry (24.4%) and traffic related (13.3%). It should be noted that road traffic emissions (traffic related and contaminated road dust) accounted for 24.7%, making them the second largest contributor to PM_2.5. Contributions of road traffic emissions significantly declined with height (29.3% to 21.4%), which was in line with the findings in previous studies, and could explain the vertical variation of PM_2.5 identified in this study. These findings help estimate the realistic exposure at different residential heights, consequently facilitating control strategy development.