Panel study using novel sensing devices to assess associations of PM2.5 with heart rate variability and exposure sources

Background/objective This work applied a newly developed low-cost sensing (LCS) device (AS-LUNG-P) and a certified medical LCS device (Rooti RX) to assessing PM 2.5 impacts on heart rate variability (HRV) and determining important exposure sources, with less inconvenience to subjects. Methods Observations using AS-LUNG-P were corrected by side-by-side comparison with GRIMM instruments. Thirty-six nonsmoking healthy subjects aged 20–65 years were wearing AS-LUNG-P and Rooti RX for 2–4 days in both Summer and Winter in Taiwan. Results PM 2.5 exposures were 12.6 ± 8.9 µg/m 3 . After adjusting for confounding factors using the general additive mixed model, the standard deviations of all normal to normal intervals reduced by 3.68% (95% confidence level (CI) = 3.06–4.29%) and the ratios of low-frequency power to high-frequency power increased by 3.86% (CI = 2.74–4.99%) for an IQR of 10.7 µg/m 3 PM 2.5 , with impacts lasting for 4.5–5 h. The top three exposure sources were environmental tobacco smoke, incense burning, and cooking, contributing PM 2.5 increase of 8.53, 5.85, and 3.52 µg/m 3 , respectively, during 30-min intervals. Significance This is a pioneer in demonstrating application of novel LCS devices to assessing close-to-reality PM 2.5 exposure and exposure–health relationships. Significant HRV changes were observed in healthy adults even at low PM 2.5 levels.