Researchers have found in a new randomized trial that using high-efficiency particulate arrestance (HEPA) filters in homes significantly reduced elevated blood pressure in individuals exposed to air pollution near major highways. However, no benefit was observed in people with normal systolic blood pressure (≤120 mm Hg). Researchers recommend targeting HEPA filtration for vulnerable populations residing in high-pollution zones. The study was published in theJournal of the American College of Cardiologyby Doug B. and colleagues. Particulate matter, and particularly PM2.5 (less than 2.5 micrometers in diameter), has been linked for decades with elevated cardiovascular risk, including hypertension. Since persons who reside near busy roads are exposed continuously to elevated levels of PM, enhancing indoor air quality may offer a focused strategy for the reduction of such risks. This pragmatic randomized crossover trial sought to determine whether HEPA filtration might be capable of providing quantitative improvements in blood pressure in such individuals. The trial included 154 adults who lived next to highways. The participants' average age was 41.1 years, 59.7% were female, and 68.2% were non-Hispanic White. Participants were predominantly from higher socioeconomic strata. The mean baseline brachial blood pressure was 118.8/76.5 mm Hg. Each residence was randomized to start with either a 1-month interval of HEPA filtration or a 1-month sham (placebo) filtration. This was followed by 1 month of washout and then 1 month of the alternate filtration. Blood pressure was measured at the start and end of each phase of filtration. PM concentrations were also tracked within a subset of homes. Linear mixed models were applied to evaluate changes in BP, controlling for different individual and temporal factors. Key Findings 154 participants enrolled; mean age 41.1 years. 59.7% female; 68.2% non-Hispanic White. Baseline BP: 118.8/76.5 mm Hg. 2.8 mm Hg reduction in SBP following HEPA filtration among individuals with SBP ≥120 mm Hg (P = 0.03). 0.2 mm Hg increase in SBP following sham filtration (P = 0.85). Net 3.0 mm Hg benefit of HEPA filtration compared to sham (P = 0.04). No effect on diastolic BP or normotensive individuals. Substantial PM reduction validated in HEPA-filtered residences. The randomized crossover trial finds that HEPA air cleaners can produce clinically relevant reductions in systolic blood pressure in adults with high baseline levels, even where ambient air pollution is relatively low. The results validate the application of indoor air filtration as an effective and non-pharmaceutical intervention to address hypertension and cardiovascular outcomes, particularly among residents of large-traffic zones. Brugge, D., Eliasziw, M., Thanikachalam, M., Kuchhal, V., Morson, C., Vazquez-Dodero, T., Mertl, A., Tallam, P., Kunwar, S., Sprague Martinez, L., Rashid, H. S., Singh-Smith, K., Gates, H., Palma, S., Goldstein-Gelb, W., Ginzburg, S. L., Hersey, S. O., Majluf, F., & Zamore, W. (2025). Effect of HEPA filtration air purifiers on blood pressure: A pragmatic randomized crossover trial. Journal of the American College of Cardiology.https://doi.org/10.1016/j.jacc.2025.06.037