Abstract
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 language | English |
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Pages (from-to) | 514-524 |
Number of pages | 11 |
Journal | Science of the Total Environment |
Volume | 654 |
DOIs | |
State | Published - Mar 1 2019 |
Keywords
- Ambient concentration
- Exposure factor
- Exposure measurement error
- Fine particles exposure of ambient origin
- Personal exposure