Table 5.
Summary of Previous Studies Evaluating Filtration Effects on Biomarker Outcomes in Healthy Adults
| Study | Intervention Duration |
Purifier Type | Pollution Decrease |
Biomarkers Improved with Intervention |
|---|---|---|---|---|
| Chuang et al. 2017[31] | 2 × 1y; no washout | House AC electret filter (MERV11/F6; non-HEPA) | PM2.5: 8.6 µg/m3 (40%) | SBP, DBP, 8-OHdG, & CRP |
| Pádro-Martínez et al. 2015[41] | 2 × 21d; no washout | Window-mounted HEPA | PNC: 4900 #/cm3 (42%) | None |
| Chen et al. 2015[42] | 2 × 48h; 2w washout | Portable electret filter (non-HEPA) | PM2.5: 55 µg/m3 (57%) | SBP, DBP, sCD40L, FeNO, MCP-1, IL-1β, & MPO |
| Kajbafzadeh et al. 2015[43] | 2 × 7d; no washout | Portable HEPA + activated carbon | PM2.5: 2.8 µg/m3 (40%) | None |
| Karottki et al. 2013[44] | 2 × 14d; no washout | House AHU H11 HEPA | PM2.5: 3.8 µg/m3 (50%) | Monocyte CD62L (only on Day 2 of intervention) |
| Weichenthal et al. 2013[45] | 2 × 7d; 1w washout | Portable electret filter (non-HEPA) | PM2.5: 37 µg/m3 (~60%)a | FEV1 & PEFR (both dependent on two outlying subjects) |
| Allen et al. 2011[46] | 2 × 7d; no washout | Portable HEPA | PM2.5: 6.2 µg/m3 (~60%)a | Reactive hyperemia index (RHI); Males only: CRP, IL-6, & band cell counts |
| Bräuner et al. 2008[47] | 2 × 48h; no washout | Portable HEPA | PM2.5: 7.9 µg/m3 (~60%)a | RHI & hemoglobin |
a
Exact percentage not given, but was instead approximated from the published data