📉 Decay Analysis

1 · Fit a decay window

Fit region: after the peak, C − baseline ≥ max(3, 5% of rise), raw CF1 < 1000 µg/m³ (the PMS5003's credible ceiling). Excluded points are hollow. Run the mixing fan during tests; fit only after mixing (protocol: 10 min for Test A/B). Default baseline is the pre-peak minimum, so start the window a few minutes before lighting the incense to capture the pre-injection level. A baseline set too high inflates k.

2 · CADR from two fits

Room volume V, m³

k_off (purifier off), h⁻¹

k_on (purifier on), h⁻¹

Enter V, k_off, k_on.

CADR = (k_on − k_off) × V. Volume converter: × × ft = – m³. Measure the room properly - a 10% volume error is a 10% CADR error.

3 · Infiltration λ from equilibrium (Test C)

Indoor/outdoor ratio R

k_off, h⁻¹

k_purifier during R, h⁻¹

Enter R and k_off. Use k_purifier = k_on − k_off for whatever purifier state was actually running while R was measured (0 if off).

λ = R × (k_off + k_purifier) · deposition = k_off − λ · predicted indoor = outdoor × λ / (k_off + k_purifier-in-future-state).