Estimation of personal exposure to fine particles (PM 2.5 ) of ambient origin for healthy adults in Hong Kong

Xiao Cui Chen, Judith C. Chow, Tony J. Ward, Jun Ji Cao, Shun Cheng Lee, John G. Watson, Ngar Cheung Lau, Steve H.L. Yim, Kin Fai Ho

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Personal exposure and ambient fine particles (PM 2.5 ) measurements for 13 adult subjects (ages 19–57) were conducted in Hong Kong between April 2014 and June 2015. Six to 21 personal samples (mean = 19) per subject were obtained throughout the study period. Samples were analyzed for mass by gravimetric analysis, and 19 elements (from Na to Pb) were analyzed using X-Ray Fluorescence. Higher subject-specific correlations between personal and ambient sulfur (r s = 0.92; p < 0.001) were found as compared to PM 2.5 mass (r s = 0.79; p < 0.001) and other elements (0.06 < r s < 0.86). Personal vs. ambient sulfur regression yielded an average exposure factor (F pex ) of 0.73 ± 0.02, supporting the use of sulfur as a surrogate to estimate personal exposure to PM 2.5 of ambient origin (E a ). E a accounted for 41–82% and 57–73% of total personal PM 2.5 exposures (P) by season and by subject, respectively. The importance of both E a and non-ambient exposures (E na , 11.2 ± 5.6 μg/m 3 ; 32.5 ± 10.9%) are noted. Mixed-effects models were applied to estimate the relationships between ambient PM 2.5 concentrations and their corresponding exposure variables (E a , P). Higher correlations for E a (0.90; p < 0.001) than for P (0.58; p < 0.01) were found. A calibration coefficient < 1 suggests an attenuation of 22% (ranging 16–28%) of the true effect estimates when using average ambient concentrations at central monitoring stations as surrogates for E a . Stationary ambient data can be used to assess population exposure only if PM exposure is dominated by E a .

Original languageEnglish
Pages (from-to)514-524
Number of pages11
JournalScience of the Total Environment
StatePublished - Mar 1 2019


  • Ambient concentration
  • Exposure factor
  • Exposure measurement error
  • Fine particles exposure of ambient origin
  • Personal exposure


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