Technical Documentation

Methodology & Data Standards

A technical overview of the National Mold Index (NMI) algorithm, referencing datasets from NOAA, the U.S. Census Bureau, and EPA remediation standards.

1. Data Sources & Architecture

The National Mold Index (NMI) aggregates geospatial climate data with user-reported structural inputs. Unlike generic checklists, our algorithm begins with a Geographic Base Score specific to the user’s zip code.

2. The Scoring Algorithm

The NMI Tool calculates risk on a logarithmic scale from 1.0 (Safe) to 9.9 (Critical). The score is dynamically adjusted by the following User Input Vectors:

Phase 1: Critical Water Events (Weight: 2.5x)

These factors represent guaranteed moisture intrusion. According to EPA standards, these conditions require professional remediation.

Variable	Risk Impact	Classification
Past Flooding History	+2.5 Points	Severe
Negative Grading (Slope)	+1.8 Points	High
Visible Growth > 10 sq ft	+3.0 Points	Critical

Phase 2: Structural Deficiencies (Weight: 1.5x)

Structural variables that prevent the building envelope from shedding water or drying out.

Variable	Risk Impact	Rationale
Crawl Space Foundation	+1.0 Points	Allows vapor rise from soil (Stack Effect).
No Gutters / Clogged	+1.2 Points	Saturates foundation soil.
Carpet in Wet Areas	+1.0 Points	Traps organic dust and moisture.
Unchecked Attic	+0.5 Points	Hidden roof leaks cause truss rot.

Phase 3: Lifestyle & Bio-Load (Weight: 0.5x – 0.8x)

Daily habits that introduce biological material (food for mold) or excess water vapor into the home environment.

Variable	Risk Impact	Mechanism
Drying Clothes Indoors	+0.8 Points	Releases ~2-4 liters of water vapor per load.
Pets (Cats/Dogs)	+0.4 Points	Dander is a protein-rich food source for spores.
Firewood Indoors	+0.3 Points	Introduces outdoor spores and retaining moisture.

Phase 4: Health Correlations (Indicator Weight)

Note: This tool does not diagnose medical conditions. However, specific symptoms are recognized by the EPA/CDC as indicators of Sick Building Syndrome (SBS).

Indicator	Risk Adjustment	Correlation
Symptoms Improve Away from Home	+2.0 Points	Strongest indicator of environmental toxicity.
Chronic Fatigue / Headaches	+0.8 Points	Common reaction to Mycotoxin exposure.

Phase 5: Protective Factors (Negative Weight)

The algorithm credits users for active mitigation strategies that lower the Relative Humidity (RH) or remove particulate matter.

Mitigation	Score Reduction	Mechanism
Dehumidifier	-1.2 Points	Active Moisture Removal (< 50% RH).
HEPA Filtration	-0.5 Points	Capture of airborne spores (0.3 microns).
Sump Pump	-0.6 Points	Active Hydrostatic Defense.

3. Risk Classification Standards

The final score correlates to specific action tiers recommended by the Institute of Inspection, Cleaning and Restoration Certification (IICRC) S500 and S520 Standards.

• Safe (1.0 – 3.9): Standard maintenance required. Monitor humidity during storms.
• Moderate (4.0 – 5.9): Protective factors recommended (Dehumidifier, Gutter Extensions).
• High Risk (6.0 – 7.9): Active deficiency detected. Structure is likely retaining moisture. Inspection recommended.
• Critical (8.0 – 9.9): Hazardous conditions probable. Professional air quality testing (IEP) strongly advised.

4. Limitations & Disclaimers

The National Mold Index provides a probabilistic risk assessment based on user-reported data and historical climate averages. It does not constitute a professional on-site inspection, medical advice, or legal counsel. Results should be verified by a licensed Indoor Environmental Professional (IEP) before making real estate or remediation decisions.