Short-Term Blood Pressure Responses to Ambient Fine Particulate Matter Exposures at the Extremes of Global Air Pollution Concentrations.

BACKGROUND: Fine particulate matter (PM2.5) air pollution is a leading cause of global cardiovascular mortality. A key mechanism may be PM2.5-induced blood pressure (BP) elevations. Whether consistent prohypertensive responses persist across the breadth of worldwide pollution concentrations has never been investigated.

METHODS: We evaluated the hemodynamic impact of short-term exposures to ambient PM2.5 in harmonized studies of healthy normotensive adults (4 BP measurements per participant) living in both a highly polluted (Beijing) and clean (Michigan) location.

RESULTS: Prior 7-day outdoor-ambient and 24-hour personal-level PM2.5 concentration averages were much higher in Beijing (86.7 ± 52.1 and 52.4 ± 79.2 µg/m3) compared to Michigan (9.1 ± 1.8 and 12.2 ± 17.0 µg/m3). In Beijing (n = 73), increased outdoor-ambient exposures (per 10 µg/m3) during the prior 1-7 days were associated with significant elevations in diastolic BP (0.15-0.17 mm Hg). In overweight adults (body mass index ≥25 kg/m2), significant increases in both systolic (0.34-0.44 mm Hg) and diastolic (0.22-0.66 mm Hg) BP levels were observed. Prior 24-hour personal-level exposures also significantly increased BP (0.41/0.61 mm Hg) in overweight participants. Conversely, low PM2.5 concentrations in Michigan (n = 50), on average within Air Quality Guidelines, were not associated with BP elevations.

CONCLUSIONS: Our findings demonstrate that short-term exposures to ambient PM2.5 in a highly polluted environment can promote elevations in BP even among healthy adults. The fact that no adverse hemodynamic responses were observed in a clean location supports the key public health importance of international efforts to improve air quality as part of the global battle against hypertension.