← Descent Analysis Indoor Air Quality Estimator
Volume I · May 2026 · 598 words
Estimate indoor PM2.5 concentration during outdoor air pollution events (wildfire
smoke, inversions, industrial plumes) based on outdoor AQI, your building's age
and construction type, and whether you're running an air purifier. The model
uses EPA infiltration factors from the 2021 Wildfire Smoke Guide.
Outdoor PM2.5 AQI
50 — Good (12 µg/m³)
100 — Moderate (35 µg/m³)
150 — Unhealthy for Sensitive Groups (55 µg/m³)
200 — Unhealthy (150 µg/m³)
300 — Very Unhealthy (250 µg/m³)
400 — Hazardous (350 µg/m³)
500 — Extreme (500 µg/m³)
Building type (infiltration factor)
Older home (pre-1990), leaky — 0.7 infiltration
Typical home (1990–2010) — 0.5 infiltration
New construction (post-2010), tight — 0.3 infiltration
Passive house / sealed with HVAC filtration — 0.1 infiltration
Windows and doors
Closed (no additional infiltration)
Occasional opening — add 0.15 infiltration
Frequently open — add 0.30 infiltration
Air purifier smoke CADR (CFM) — 0 if none
None — no air purifier
150 CFM — Small purifier (bedroom size)
233 CFM — Coway AP-1512HH (medium room)
410 CFM — Levoit Core 600S (large room)
600 CFM — Dual purifier setup
Room size (square feet, 8 ft ceiling assumed)
Estimated indoor PM2.5 (no purifier) —
Estimated indoor PM2.5 (with purifier) —
Indoor AQI equivalent —
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