Understanding your indoor air quality report is essential for taking the right corrective actions. Learn how to interpret test results, identify priority concerns, and have informed conversations with qualified professionals.
Mold air sample laboratory reports list results as spores per cubic meter (sp/m³) for each identified genus or species. The report should include at least one outdoor control sample — ideally collected from the upwind side of the building during the same time window as indoor samples. The comparison between indoor and outdoor is more informative than any single number.
Key species to understand: Cladosporium and Basidiospores are ubiquitous outdoors and commonly found indoors — elevated indoor counts that mirror outdoor counts of the same species are less concerning than an indoor-only spike. Penicillium and Aspergillus are typically grouped together by labs (P/A) because their spores are morphologically similar under microscopy; elevated P/A indoors relative to outdoor is a significant finding. Stachybotrys and Chaetomium are water-damage indicator species — they are rarely found outdoors in significant numbers, so any meaningful indoor detection warrants investigation.
The AIHA’s consensus guidance suggests that an indoor/outdoor (I/O) ratio above 1.5 for total spore counts, combined with a species profile that differs from outdoor air, is generally considered significant. However, interpretation is contextual — an assessor’s written interpretation is more valuable than any single ratio.
A broad IAQ report covers more than mold. CO2 readings are typically reported as averages and peaks during occupancy. ASHRAE’s ventilation standard uses 1,000 ppm as a general guideline for acceptable ventilation — consistently higher readings in occupied spaces indicate inadequate outdoor air exchange. Some assessors use the simplified ASHRAE formula: outdoor air ventilation rate ≈ (CO2 indoor – CO2 outdoor) / (CO2 exhaled – CO2 outdoor), where exhaled CO2 is approximately 35,000–40,000 ppm.
PM2.5 readings in a professional report are typically expressed as 24-hour averages or short-term (1-hour) averages in micrograms per cubic meter (µg/m³). The EPA’s NAAQS 24-hour PM2.5 standard is 35 µg/m³ — though the WHO recommends a more protective 15 µg/m³. Values consistently above 12 µg/m³ in residential settings (EPA’s annual average standard) suggest an ongoing particle source worth investigating.
VOC results in professional reports may be expressed as total VOCs (TVOCs) in ppb, or as individual compound concentrations. TVOC has limited regulatory standing — the EPA does not set indoor TVOC standards — but a TVOC above 500 ppb indoors generally warrants investigation of sources. Individual compounds of concern (formaldehyde, benzene, toluene) have published reference concentrations from the EPA’s IRIS database that a qualified assessor uses for comparison.
When a Florida mold assessor finds contamination, they are required to provide a written remediation protocol. This document is the scope of work for the remediator — read it carefully before signing any remediation contract.
A proper protocol specifies: the affected areas and materials (by room and material type); the remediation standard to be followed (IICRC S520, EPA mold remediation guidance, or AIHA guidelines); containment requirements (critical barriers, negative air pressure, decontamination chambers); personal protective equipment for workers; and post-remediation clearance testing requirements including who must perform it (it must be a licensed assessor, not the remediator).
Be cautious if: the remediation scope seems far larger than what the assessment found; the protocol does not specify a clearance test; the assessor recommends a specific remediator; or the costs quoted seem disproportionate to the findings. Florida law gives you the right to get a second opinion from another licensed assessor before proceeding with any remediation work.
Signs of poor indoor air quality, when to schedule a professional inspection, and what gets tested during an indoor air quality assessment.
learn more
What a licensed Florida mold inspector looks for, how mold testing works, and what to expect from a professional mold inspection in South Florida.
Home air quality test kits, how accurate they are, what they can and can’t detect, and when professional testing is worth it instead.
Mold reports, indoor air quality assessments — each one looks different. What the numbers mean, and what to do with the results.
Whether you’re tracking down a smell, dealing with allergy flare-ups, or managing a building — we publish plain-language guidance rooted in EPA, ASHRAE, and NADCA standards. Reach out anytime.