Background

Given the lack of research on the personal exposure to fine particles (PM_2.5) in Hong Kong, we examined the association between short-term personal exposure to PM_2.5 and their constituents and inflammation in exhaled breath in a sample of healthy adult residents.

Method

Forty-six participants underwent personal PM_2.5 monitoring for averagely 6 days to obtain 276 samples. Fractional exhaled nitric oxide (FeNO), a biomarker of inflammation in exhaled breath, was measured at the end of each 24-h personal monitoring. PM_2.5 chemical constituents, including organic carbon, elemental carbon, 16 polycyclic aromatic hydrocarbons (PAHs), and 6 phthalate esters, were speciated from the personal samples collected. A mixed-effects model was used to estimate the association of PM_2.5 and their constituents with FeNO. The comparison was also made with parallel analyses using ambient concentrations.

Results

Personal exposures to PM_2.5 (28.1 ± 23.3 μg/m³) were higher than the ambient levels (13.3 ± 6.4 μg/m³) monitored by stations. The composition profile and personal-to-ambient concentration ratio varied among subjects with different occupations. An interquartile range (IQR) change in personal exposure to PM_2.5 was positively associated with 12.8% increase in FeNO (95% confidence interval, CI: 5.5–20.7%), while nil association was found for ambient PM_2.5. Among the constituents measured, only the carcinogenic PAHs were significantly associated with 12% increase in FeNO responses (95% CI, 0.0–25.6%).

Conclusion

In conclusion, our study provides the first understanding about personal exposure to PM_2.5 and possible sources in Hong Kong. The results also showed that personal exposure to PM_2.5 and c-PAHs were linked to increased FeNO levels among healthy adults.