Mold can have a troubling presence in homes and buildings, especially in damp or poorly ventilated spaces. While many people are aware that mold can lead to allergies and respiratory problems, they may not know that mold can affect our health in different ways. Mold produces several byproducts, including mold spores, mold volatile organic compounds (MVOCs), and mycotoxins. Each of these has unique properties and poses different risks to health and indoor air quality.
Below we will explore the differences between mold spores, MVOCs, and mycotoxins to help you better understand how mold can impact your living environment and health.
- Mold Spores: The Seeds of Mold Growth
Mold spores are everywhere—both indoors and outdoors. Mold spores are microscopic, reproductive units produced by molds to help them spread and colonize new areas. Like the seeds of plants, mold spores are released into the air and looking for the right conditions to reproduce and grow.
How Mold Spores Affect Health
Mold spores are a major cause of indoor air quality problems and can affect human health, particularly in people with allergies or respiratory conditions. When mold spores are inhaled, they can cause:
- Allergic reactions: Symptoms include sneezing, itchy eyes, a runny nose, and skin rashes.
- Asthma flare-ups: Mold spores are a common trigger for people with asthma, causing wheezing and difficulty breathing.
- Respiratory issues: Prolonged exposure to high levels of mold spores can lead to chronic respiratory problems, including coughing and shortness of breath.
People with weakened immune systems, young children, and the elderly are more vulnerable to the effects of mold spores. In general, mold spores can be an irritant to anyone when they are present in high concentrations.
- MVOCs: The Gases Molds Emit During Growth
Mold volatile organic compounds (MVOCs) are chemicals released as gases by actively growing molds. These compounds are a byproduct of mold’s metabolic processes—like plants releasing oxygen during photosynthesis, molds emit MVOCs into the air as they break down organic matter for food. MVOCs contribute to the musty, earthy smell often associated with moldy environments.
How MVOCs Affect Health
MVOCs are responsible for the unpleasant odors that often signal mold growth, but their effects go beyond just causing a bad smell. Depending on the specific compounds released by the mold, exposure to MVOCs may cause various symptoms, including:
- Headaches: Prolonged exposure to MVOCs can lead to headaches or migraines, especially in enclosed spaces.
- Dizziness or nausea: Some people may feel lightheaded, dizzy, or nauseous after being exposed to the strong odors of MVOCs.
- Eye, nose, and throat irritation: MVOCs can irritate the mucous membranes, causing itchy eyes, a sore throat, and runny nose.
Although MVOCs can cause discomfort and irritation, their long-term health effects are not as well-studied as other mold-related byproducts like mycotoxins. However, frequent exposure to MVOCs can exacerbate symptoms for people with chemical sensitivities or respiratory issues.
- Mycotoxins: Toxins Molds Can Release When Threatened
Mycotoxins are toxic compounds produced by certain species of molds, including Stachybotrys chartarum, Aspergillus, and Penicillium. These toxins are not released as volatile gases like MVOCs, but are instead Semi-Volatile, condensing quickly onto particulates in the air (spores, mold fragments, and common dust). Mycotoxins are secondary metabolites, meaning that they are not essential to the mold’s survival but can serve as a defense mechanism against other microorganisms.
How Mycotoxins Affect Health
Exposure to mycotoxins is more concerning than exposure to mold spores or MVOCs because of the potential for serious health effects. Mycotoxin exposure is most commonly through ingestion of contaminated foods; inhalation or skin contact with mycotoxin-laden particulates is also a potential route of exposure. Health effects of mycotoxins can include:
- Neurological symptoms: Mycotoxins can affect the central nervous system, leading to symptoms such as dizziness, fatigue, memory loss, and cognitive impairment.
- Respiratory issues: Inhalation of mycotoxins can cause respiratory problems such as coughing, wheezing, and chest tightness, similar to the symptoms caused by mold spores, but with potentially more severe consequences.
- Immune system suppression: Prolonged exposure to mycotoxins may weaken the immune system, making it harder for the body to fight off infections.
- Chronic inflammation: Mycotoxins can lead to chronic inflammation, which may manifest as joint pain, skin irritation, or other long-term health issues.
It’s important to note that not all molds produce mycotoxins, and the severity of health effects can depend on the type of mycotoxin and the duration of exposure. People who are particularly vulnerable to mycotoxin exposure include those with pre-existing health conditions, weakened immune systems, or respiratory diseases.
Key Differences Between Mold Spores, MVOCs, and Mycotoxins
Here’s a quick summary of the differences between these three mold-related byproducts:
| Mold Spores | Mold Volatile Organic Compounds (MVOCs) | Mycotoxins | |
| Form | Microscopic particles, released for reproduction | Volatile gases released during mold metabolism | Semi-volatile toxic compounds present in certain mold species |
| Source | All molds produce spores | Only actively growing molds emit MVOCs | Only specific molds (e.g., Stachybotrys, Aspergillus) |
| Health Effects | Allergies, respiratory irritation, asthma | Headaches, dizziness, irritation | Neurological issues, respiratory problems, immune suppression |
| Detection | Visible mold growth or particulate tests (surface or air) | Musty odors or chemical air quality testing | Mold species identification or professional dust assessment (ERMI) |
| Prevention | Address any visible mold colonies, clean surfaces regularly | Control moisture, increase fresh air ventilation and/or purification | Control the moisture and watch for mold growth signs |
Understanding the differences between mold spores, MVOCs, and mycotoxins is key to protecting your health. The best way to prevent exposure to these mold byproducts is to control moisture, address mold growth promptly, and maintain a clean, well-ventilated environment. By staying vigilant and taking proactive steps, you can avoid molds compromising the health of your home—or the health of the people living in it.