Published: June 19, 2025
By: Full Spectrum Environmental, Palm Beach County
What Are MVOCs?
Microbial Volatile Organic Compounds (MVOCs) are gases released by mold and bacteria as they grow. These include alcohols, ketones, esters, and sulfur-based compounds. They’re often responsible for the musty, earthy, or “chemical” smells associated with mold-contaminated buildings.
MVOCs = Mold odor (not always dangerous, but worth investigating)
MVOCs are volatile, meaning they easily enter the air and can be inhaled. Some MVOCs can cause mild irritation to eyes, nose, or throat—especially for people with allergies, asthma, or chemical sensitivity.
What Are Mycotoxins?
Mycotoxins are secondary metabolites produced by certain molds like Stachybotrys, Aspergillus, and Penicillium. Unlike MVOCs, they don’t have an odor and they don’t float through the air as gasses. Instead, they stick to dust, surfaces, and HVAC components.
These toxins are biologically active—even in small amounts. They’ve been linked to a range of health concerns:
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Immune dysregulation
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Neurological issues
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Inflammatory responses
Mycotoxins = Invisible toxic particles (no odor, high health concern)
Key Differences
| Feature | MVOCs | Mycotoxins |
|---|---|---|
| What they are | Mold-related gases | Toxic mold byproducts |
| Can you smell them? | Yes – musty, earthy, or chemical odor | No – odorless |
| Health risk | Mild to moderate irritant | High – potential toxic exposure |
| How they spread | Through air (volatile gas) | On dust, surfaces, and HVAC components |
| Common molds | All mold can produce MVOCs | Only specific species under conditions |
Why It Matters
Just because a building smells musty doesn’t mean it has a toxic mold problem—but odor is a clue that something microbial is active.
That’s why we take a layered approach to indoor environmental testing:
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Spore trap testing to identify mold species in the air
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Moisture diagnostics to locate hidden growth
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Dust and surface sampling
Mycotoxin & Mold “Toxicity” Test Limitations
According to the American Academy of Allergy, Asthma & Immunology, urine or blood tests for mycotoxins—sometimes marketed as assessments for “toxic mold”—are not FDA-approved and lack scientific validation. These tests are often sold directly to consumers with no standardized thresholds or proven health relevance. While mold exposure in damp buildings is linked to allergic symptoms, the connection to systemic illness from inhaled mycotoxins is unproven.
Here’s what the AAAAI and other authorities recommend instead:
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Focus on air and surface fungal sampling to identify where mold is growing.
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Conduct a thorough moisture intrusion inspection to find water leaks and prevent mold development.
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Rely on well-established, evidence-based methods—not unvalidated urine or blood mycotoxin tests—for accurate mold assessment.
Palm Beach County Testing You Can Trust
If your home smells like mold — don’t guess — Let our team at Full Spectrum Environmental perform a comprehensive assessment tailored to your home or office.