CLEAR THE AIR: The Homeowner’s Wellness Guide to Preventing Mold

By Rick Weber

Louisiana is the only state whose homes are more likely to develop mold than ours here in Florida. It’s just a fact of life with our humid, subtropical climate, frequent rainfall and high temperatures that provide ideal breeding conditions.

The key drivers include:
. High humidity: Moisture builds up within walls and air ducts due to year-round humidity.
. Storms and flooding: Hurricanes and tropical storms frequently cause structural and roof leaks, with mold growing within 24 to 48 hours of water intrusion.
. HVAC condensation: Overworked air conditioning systems and blocked vents are common sources of hidden moisture.

“Homes should be well maintained, properly ventilated and the temperature controlled to prevent the growth of microorganisms,” says Jay Gupta, M.D., Ph.D., a professor and director of the undergraduate Public Health program in the Department of Health Sciences at Florida Gulf Coast University’s Marieb College of Health & Human Services.

“The telltale signs of indoor dampness and microbial growth are a history of water damage to the home, condensation on inside surfaces, visible mold and a typical musty odor from gases released by mold. Should dampness occur, remediation measures should be adopted as soon as possible.”

Gupta says mold is a type of fungi—organisms that cannot be classified either as plants or as animals. They cannot prepare their own food but depend on external sources for nutrition. They are found in all environments, both outdoors and indoors, and play a crucial ecological role in decomposing organic matters.

Common fungi include mushrooms, yeasts and molds. He says that while most fungi are harmless, a few have the potential to affect human health adversely. While some molds can cause infections in susceptible individuals and can produce toxins harmful to humans, they are most commonly associated with allergic symptoms including asthma exacerbation, upper respiratory tract symptoms, cough and wheeze.

“While molds are present everywhere in the natural environment, they are typically of health concern only when they multiply in the closed indoor environment,” he says. “However, microbial pollution affecting the indoor environment involves not only molds and other fungi, but other microorganisms including bacteria. These multiply in the presence of sufficient moisture (dampness) and inadequate ventilation.

“The World Health Organization guidelines for indoor air quality: dampness and mould (2009) note that dampness is considered the key risk indicator behind the health risks associated with mold and other microbial contamination. While water leaks and natural events such as heavy rain and flooding can introduce moisture inside buildings, the major source of moisture in the indoor environment is incoming air. Since proper ventilation helps to remove pollutants and moisture from indoor air, inadequate ventilation is an important determinant of dampness and growth of microorganisms in the indoor environment.

“Dampness is more likely to be observed in low-income communities where homes are overcrowded or are not properly ventilated, and insufficiently heated or insulated during winter. The health effects most commonly associated with indoor dampness for which sufficient evidence exists in scientific literature are asthma exacerbation, upper respiratory tract symptoms such as runny nose, sneezing and sore throat, cough and wheeze. While people who have known allergies are typically the most affected, these health effects have also been observed in non-allergic people.”

Also, more frequent storms attributed to a global rise in temperature causing heavy rainfall and flooding are of particular concern in coastal cities and towns such as Fort Myers, as these events can increase the proportion of damp buildings.

As an environmental epidemiologist, Gupta has been a part of several peer-reviewed articles on the association between microbial exposure and human health, the latest being an article, “Assessment of Mold-Specific Volatile Organic Compounds and Molds Using Sorbent Tubes and a CDC/NIOSH-Developed Tool in Homes Affected by Hurricane Ian,” published in the journal Applied Sciences in 2025.

The study highlights the persistent risk of hidden microbial contamination in flood-affected homes, even when visible mold growth is absent.

The recommendations were: “The study outcomes emphasize the need for post-flood remediation strategies that extend beyond superficial cleaning and renovation, incorporating continuous monitoring to guide moisture control, targeted disinfection and safe re-occupancy. Therefore, protecting vulnerable populations in hurricane-affected regions requires moving beyond visual assessments. Coordinated public health and housing policies should integrate assessments of hidden moisture and Mold-Specific Volatile Organic Compounds to guide effective remediation, safe re-
occupancy decisions and long-term monitoring programs. Future research should expand to larger, more diverse populations, standardize sampling protocols and directly link environmental contamination with occupant health outcomes.”

Gupta says that while people have developed a greater awareness toward mold and mold-related issues in recent years, misconceptions are widespread.

“Out of millions of mold species on earth, the vast majority are harmless—indeed, ecologically beneficial—and coexist peacefully with humans. Only a few have the potential to cause illness: typically, allergies and upper respiratory tract infections in susceptible individuals. According to the published scientific literature, most reports of serious illnesses from exposure to ‘toxic black mold’ and the so-called ‘sick building syndrome’ from exposure to molds are media hype and collective hysteria and are not supported by solid scientific evidence.”

The undergraduate Public Health program at FGCU (Bachelor of Science in Public Health) includes several courses that cover illnesses resulting from fungal and other microbial exposures.

FGCU
Marieb College of Health & Human Services

10501 FGCU Boulevard South, Fort Myers, FL 33965
(239) 590-1000 | fgcu.edu

References:
1. World Health Organization. (2009). WHO guidelines for indoor air quality: dampness and mould. WHO Regional Office for Europe. https://www.who.int/publications/i/item/9789289041683
2. Hardin BD, Kelman BJ, Saxon A. Adverse human health effects associated with molds in the indoor environment. J Occup Environ Med. 2003 May;45(5):470-8. doi: 10.1097/00043764-200305000-00006. PMID: 12762072.
3. Borchers AT, Chang C, Eric Gershwin M. Mold and Human Health: a Reality Check. Clin Rev Allergy Immunol. 2017 Jun;52(3):305-322. doi: 10.1007/s12016-017-8601-z. PMID: 28299723.
4. Adhikari, A., Jegede, O., Ezeamii, V. C., Ayo-Farai, O., Savarese, M., & Gupta, J. (2025). Assessment of Mold-Specific Volatile Organic Compounds and Molds Using Sorbent Tubes and a CDC/NIOSH-Developed Tool in Homes Affected by Hurricane Ian. Applied Sciences, 15(19), 10805. https://doi.org/10.3390/app151910805