Determinants of personal exposure to fine particulate matter (PM2.5) in adult subjects in Hong Kong

Xiao-Cui Chen; Tony J Ward; Jun-Ji Cao; Shun-Cheng Lee; Judith C Chow; Gabriel N C Lau; Steve H L Yim; Kin-Fai Ho

doi:10.1016/j.scitotenv.2018.02.049

Determinants of personal exposure to fine particulate matter (PM_2.5) in adult subjects in Hong Kong

Sci Total Environ. 2018 Jul 1:628-629:1165-1177. doi: 10.1016/j.scitotenv.2018.02.049. Epub 2018 Feb 20.

Authors

Xiao-Cui Chen¹, Tony J Ward², Jun-Ji Cao³, Shun-Cheng Lee⁴, Judith C Chow⁵, Gabriel N C Lau⁶, Steve H L Yim⁷, Kin-Fai Ho⁸

Affiliations

¹ Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, Hong Kong, China.
² School of Public and Community Health Sciences, University of Montana, Missoula, MT, USA.
³ Key Laboratory of Aerosol, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China; Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an, China.
⁴ Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China.
⁵ Key Laboratory of Aerosol, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China; Division of Atmospheric Sciences, Desert Research Institute, NV 89512-1095, USA.
⁶ Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, Hong Kong, China; Department of Geography and Resource Management, The Chinese University of Hong Kong, Hong Kong, China.
⁷ Department of Geography and Resource Management, The Chinese University of Hong Kong, Hong Kong, China; Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, Hong Kong, China.
⁸ Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, Hong Kong, China; The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China; Key Laboratory of Aerosol, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China. Electronic address: kfho@cuhk.edu.hk.

PMID: 30045539
DOI: 10.1016/j.scitotenv.2018.02.049

Abstract

Personal monitoring for fine particulate matter (PM_2.5) was conducted for adults (48 subjects, 18-63years of age) in Hong Kong during the summer and winter of 2014-2015. All filters were analyzed for PM_2.5 mass and constituents (including carbonaceous aerosols, water-soluble ions, and elements). We found that season (p=0.02) and occupation (p<0.001) were significant factors affecting the strength of the personal-ambient PM_2.5 associations. We applied mixed-effects models to investigate the determinants of personal exposure to PM_2.5 mass and constituents, along with within- and between-individual variance components. Ambient PM_2.5 was the dominant predictor of (R²=0.12-0.59, p<0.01) and the largest contributor (>37.3%) to personal exposures for PM_2.5 mass and most components. For all subjects, a one-unit (2.72μg/m³) increase in ambient PM_2.5 was associated with a 0.75μg/m³ (95% CI: 0.59-0.94μg/m³) increase in personal PM_2.5 exposure. The adjusted mixed-effects models included information extracted from individual's activity diaries as covariates. The results showed that season, occupation, time indoors at home, in transit, and cleaning were significant determinants for PM_2.5 components in personal exposure (R²_β=0.06-0.63, p<0.05), contributing to 3.0-70.4% of the variability. For one-hour extra time spent at home, in transit, and cleaning an average increase of 1.7-3.6% (ammonium, sulfate, nitrate, sulfur), 2.7-12.3% (elemental carbon, ammonium, titanium, iron), and 8.7-19.4% (ammonium, magnesium ions, vanadium) in components of personal PM_2.5 were observed, respectively. In this research, the within-individual variance component dominated the total variability for all investigated exposure data except PM_2.5 and EC. Results from this study indicate that performing long-term personal monitoring is needed for examining the associations of mass and constituents of personal PM_2.5 with health outcomes in epidemiological studies by describing the impacts of individual-specific data on personal exposures.

Keywords: Fine particulate matter; Mixed-effects model; Particulate constituents; Personal exposure; Time-activity diaries.