HEPA air filter from Austin Air (even without the charcoal or zeolite coating layer) reduces systolic blood pressure slightly (maybe up to 3 mmHg) if you have high blood pressure: https://www.jacc.org/doi/10.1016/j.jacc.2025.06.037#abstract

Preventive medicine should not be housed in the same system that manages disease. One is about keeping people healthy. The other profits when they’re sick. "Show me the incentives and I'll show you the outcomes" Time to decouple them for good.