Indoor/Outdoor Spore Ratio Clearance Screen

The everyday mold clearance read: post-remediation indoor airborne spore concentration should sit at or below the outdoor control (ratio at or under 1), with no indoor-dominant water-damage marker genera (Stachybotrys, Chaetomium) elevated inside. Computes the indoor/outdoor ratio and screens the marker flag. A screen, not a clearance certificate; an independent environmental professional interprets the genera and the full criteria (ANSI/IICRC S520).

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Formula and source

io_ratio = indoor_spores_m3 / outdoor_spores_m3; pass when io_ratio <= 1 and no indoor-elevated water-damage marker (indoor_marker == 0).

Indoor/outdoor airborne-spore comparison and the marker-genera (Stachybotrys / Chaetomium) principle of ANSI/IICRC S520, by name. Not edition-bound.

Audience

This tile is built for restoration and the adjacent professions in the Water Damage and Mold Restoration group. The interactive calculator runs entirely in your browser. No account, no fee, no advertising, no tracking.

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Posture

Rough Logic answers the math question the working professional asks on the job. The site is a calm, fast, ad-free, account-free, ever-free reference. It does not interpret code. It does not replace the licensed professional. It does not store your inputs. The Authority Having Jurisdiction governs all installations and inspections.