Invisible pollution and hypertension: Evidence from the aging population in China

Hypertension, a prevalent health concern within China's aging population, is the focal point of this study. The aim is to draw causal conclusions on the impact of ozone pollution on hypertension incidence and blood pressure elevation, using an instrumental variable derived from the wind-borne long-distance transmission of ozone. The findings suggest a causal effect of ozone on blood pressure and hypertension incidence; a one-part-per-billion increase in the ambient ozone level during the preceding four months causes a rise in systolic and diastolic blood pressure (0.5281 mmHg and 0.3796 mmHg, respectively), and a 0.52 percentage point surge in hypertension incidence. These effects are potentially due to physiological and behavioral factors, including elevated inflammation and oxidative stress, increased obesity rates, and reduced sleep duration. Importantly, this study emphasizes the substantial health benefits achievable through ozone pollution control. A one-standard-deviation decrease in ozone concentration could potentially result in an estimated reduction of 28.13 million hypertensive older adult patients by mid-century, consequently lowering medical expenditure by approximately 3.83 billion USD.