Personal exposure to fine particulate air pollutants impacts blood pressure and heart rate variability

Air pollution has increasingly been recognized as a major healthcare concern. Air pollution, particularly fine particulate matter (≤ 2.5 μm in aerodynamic diameter [PM_2.5]) has demonstrated an increase in adverse cardiovascular events. This study aimed to assess the cardiovascular response to personal exposure to different levels of PM_2.5. This prospective cohort study enrolled healthy volunteers aged ≥ 18 years with no cardiovascular disease. Study subjects carried personal exposure monitor of PM_2.5, digital thermo-hygrometer for temperature and humidity, 24-h blood pressure monitor, and continuous electrocardiogram monitor. Measurements were repeated twice with an interval of 6-12 months. Statistical models consisted of generalized estimation equations to various repeated measures of each subject. A total of 22 subjects were enrolled in this study between July 2018 and January 2019. Measurement was performed twice in all participants, and a total of 36 data were collected except for insufficient data collection. The mean age of the study population was 41.6 years, and 95% of the subjects were females. No study subjects had hypertension or other cardiovascular diseases. The average systolic blood pressure increased with higher PM_2.5 levels with marginal significance (0.22 mmHg [95% confidential intervals - 0.04 to 0.48 mmHg] per 10 μg/m³ of PM_2.5). All parameters for heart rate variability significantly decreased with a higher level of PM_2.5. In this study, we measured individual personal exposure to PM_2.5 by using a portable device. We found that 24-h exposure to high levels of PM_2.5 was associated with a significant decrease in heart rate variability, suggesting impaired autonomous nervous function.