Wildfire smoke tool
Wildfire Clean Air Room Planner
Enter room size and ceiling height to see the EPA-style minimum smoke CADR target, the resulting ACH, and how published DIY air-cleaner designs compare.
EPA portable-air-cleaner sizing
EPA wildfire guidance says to choose a portable air cleaner with a smoke CADR of at least two-thirds of the room area in square feet. EPA also recommends MERV 13 or higher for compatible central HVAC systems and says commercial air cleaners with known CADR are generally preferred over DIY designs.
DIY designs can still be useful
EPA research measured materially different smoke CADR depending on DIY design. A basic one-filter box fan was measured around 111 CFM, while a four-filter Corsi-Rosenthal design with shroud was measured around 401 CFM in the cited study. Build quality and fan/filter configuration matter.
Sources: EPA indoor air filtration ↗ · EPA DIY air-cleaner research ↗