This is a question we get a lot!
In the early 1990’s, there was a major health scare in Cleveland. Within about 48 hours, 4 infants were brought to a local hospital with a relatively rare condition at the time: their lungs were bleeding internally. This activity was reported to the CDC, as normally only 1 in 1 million infants suffer from this sort of sickness. They thought there was some kind of epidemic.
After a few years of study, it was realized that the majority of the cases that were sprouting up in Cleveland were from a lower-income neighborhood, where homes had been primarily constructed of wood, and where there had been a previous history of flooding. A 1997 NY Times article summarizes this story and is linked here: Infants’ Lung Bleeding Traced to Toxic Mold (https://www.nytimes.com/1997/01/24/us/infants-lung-bleeding-traced-to-toxic-mold.html)
The species of mold identified that seemed to be causing this issue was Stachybotrys Chartarum. This is what we commonly refer to as ‘black mold.’ It has a tendency to grow in areas where water has been standing for a few days. It is typically what we refer to as a ‘marker’ spore, demonstrating there might have been a water intrusion issue in a property at some point.
All this said, there are more than 300,000 fungal species on the planet. We simply have not had time to study the extent of human reactions to each one. There are several species that have been identified as potentially harmful to humans, but the list is certainly not complete.
There are two ways that the mold species can be identified, though identification may not always be necessary…not necessary, because, of course, if you see mold, there simply is no reason to risk not getting it remediated.
1. A local inspector or environmental company (like ours) can perform a swab of a particular section of growth to determine the species content. While this identifies the species present, it DOES NOT identify the concentration of those molds in the air, thus not giving us an indicator of a real air quality issue. That said….if you can see the mold, you should probably get it cleaned up.
2. A local inspector, environmental company, or homeowner can acquire or use an air sampling device then send the air sample to a lab for further testing. Air samples will tell us species AND concentrations in the air, thus allowing us to diagnose a larger issue. Typically, you can say that you have an air quality issue if your air samples show higher spore counts per cubic meter of air than what would typically occur outside. Typical pricing for professional sampling can range from $250–500.
The extent of mold effect on overall health in adults is simply a very large unknown. I know from personal experience that most people can have severe allergic reactions to high concentrations of mold in the air. I myself have been rendered completely ineffective for several days following spending an hour or so within a moldy apartment without a respirator. There’s just no reason to take that kind of risk with health.
My recommendation would be that regardless of the species or concentration of mold, that you strongly consider professional remediation, and at the least, a professional consultation to determine if what you are seeing requires remediation. While some homeowners opt to perform cleanup themselves, I know from experience that most people do not resolve the issue completely, thus allowing mold to grow back over a period of time.
I hope this helps. Here’s to your health.