Abstract
Portable air cleaners (PACs) can reduce blood pressure (BP) by decreasing fine particulate matter (PM(2.5)) air pollution exposure. However, the effectiveness of a single PAC in a bedroom and the impact on self-measured home BPs over 4 weeks have not been evaluated. We conducted a randomized-order double-blind cross-over trial of active PAC (HEPA filter in-place) versus sham (no filter) intervention in the bedroom of older adults living in a senior residential facility from 1/11/2021-11/4/2024. Each study limb lasted 4 weeks with a 2-week washout period. Participants measured triplicate home BPs in the mornings and evenings during weeks 1 and 4. Bedroom PM(2.5) concentrations were continuously monitored, and 24-h personal exposures were determined during week 4. Results from 33 participants (74.9 ± 7.7 years old) completing the trial were analyzed. Active PAC intervention reduced bedroom PM(2.5) concentrations (1.3±1.5 vs. 8.3±12.8 µg/m(3), p < 0.001) and 24-h personal exposures (5.1 ± 4.6 vs. 12.4±15.6 µg/m(3), p < 0.001) versus sham. Average home systolic BP levels did not differ during active PAC versus sham intervention in the full study cohort (127.0 ± 16.2 vs. 126.5 ± 16.0 mm Hg, p = 0.59). However, having a larger body mass index plus higher baseline systolic BP, older age plus higher baseline systolic BP, and older age plus larger body mass index showed trends for modifying the benefits by active PAC. We showed for the first time that air filtration in the bedroom alone can successfully reduce PM(2.5) exposures. While systolic BPs were not lowered over 4 weeks in the entire cohort, some individuals may have benefited.