Short-term effects of real-time personal PM2.5 exposure on ambulatory blood pressure: A panel study in young adults

Background: Short-term exposure to PM2.5 has been shown to be associated with changes in blood pressure. However, most of the evidence is based on PM2.5 measurements from fixed stations and resting blood pressure measured at a regular time. Objectives: To evaluate the short-term daily and hourly effects of real-time personal PM2.5 exposure on ambulatory blood pressure, and to compare the effects with those of PM2.5 exposure from fixed stations. Methods: Between April 2017 and December 2017, 37 young adultswere recruited in a panel study froma central urban area and a suburban area, to measure personal hourly PM2.5 and ambulatory systolic blood pressure (SBP) as well as diastolic blood pressure (DBP) for three consecutive days. Hourly PM2.5 concentrations were also obtained from the nearest monitoring station operated by Guangdong Environmental Monitoring Center. Generalized additive mixed model was employed to evaluate the effects of PM2.5 on ambulatory blood pressure. Results: During the study period, the mean concentration of personal PM2.5 exposure was 60.30 +/- 52.14 mu g/m(3), while the value of PM2.5 from fixed stations was 36.77 +/- 21.52 mu g/m(3). Both personal PM2.5 exposure and exposure from fixed stations averaged over the previous 1 to 3 days decreased blood pressure. During daytime, a 10 mu g/m(3) increase in 1-day moving average of personal PM2.5 was associated with a 0.54 mmHg (95% CI: -1.03, -0.05) and 0.22 mmHg (95% CI: -0.59, 0.15) decrease in SBP and DBP, respectively. When using PM2.5 exposures from fixed stations, the decrease in SBP and DBP were 0.95 mmHg (95% CI: - 1.82, -0.07) and 0.74 mmHg (95% CI: -1.46, -0.03). Stratified analysis showed stronger effects in the central urban area and among males. Conclusions: Both personal PM2.5 exposure and exposure from fixed stations averaged over the previous 1 to 3 days decreased blood pressure. Stronger effects were found in a central urban area and among males. (C) 2019 Elsevier B.V. All rights reserved.