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

Short-term exposure to PM_2.5 has been shown to be associated with changes in blood pressure. However, most of the evidence is based on PM_2.5 measurements from fixed stations and resting blood pressure measured at a regular time.

To evaluate the short-term daily and hourly effects of real-time personal PM_2.5 exposure on ambulatory blood pressure, and to compare the effects with those of PM_2.5 exposure from fixed stations.

Between April 2017 and December 2017, 37 young adults were recruited in a panel study from a central urban area and a suburban area, to measure personal hourly PM_2.5 and ambulatory systolic blood pressure (SBP) as well as diastolic blood pressure (DBP) for three consecutive days. Hourly PM_2.5 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 PM_2.5 on ambulatory blood pressure.

During the study period, the mean concentration of personal PM_2.5 exposure was 60.30 ± 52.14 μg/m³, while the value of PM_2.5 from fixed stations was 36.77 ± 21.52 μg/m³. Both personal PM_2.5 exposure and exposure from fixed stations averaged over the previous 1 to 3 days decreased blood pressure. During daytime, a 10 μg/m³ increase in 1-day moving average of personal PM_2.5 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 PM_2.5 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.

Both personal PM_2.5 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.