FAMU-FSU College of Engineering researchers find factors that cause respiratory impacts after flooding

Researchers at the FAMU-FSU College of Engineering and Florida State University’s Resilient Infrastructure and Disaster Response Center have identified how hurricane flooding can impact health long after a storm.

In research published in the Journal of Cleaner Production, the researchers identified the factors that are most likely to create hazardous respiratory conditions inside homes after flooding.

Roof age, prevalence of indoor mold spores and maximum flood depth led to the most new respiratory symptoms among people in the homes the researchers studied. Airflow rates in bathroom exhaust fans, how often people opened their window blinds and the airtightness of the building were also important factors.

“We pay a lot of attention to direct impacts immediately after storms, but hazardous conditions can linger after floodwaters recede,” said Assistant Professor Ebrahim Ahmadisarhaf, a study co-author. “Although the respiratory health impacts of flooding are indirect and may emerge gradually, timely intervention offers the best chance for supporting health. We wanted to pinpoint which factors were most harmful, because that tells us where intervention can do the most good.”

Understanding post-flooding impact

The researchers examined residential buildings that were damaged after Hurricane Ida, which made landfall near New Orleans in 2021 before moving through the Northeast US, and Hurricane Ian, which passed through South Florida in 2022. They separated their data geographically into three groups: Louisiana, Northeast US and Central and Southern Florida.

Working with public health researchers, they surveyed people whose homes had been impacted by the two hurricanes. Because flood-related mold exposures and respiratory health effects can persist after major storms, researchers conducted health surveys and mold sampling five to seven months after the hurricanes impacted the study area.

The team combined survey results with home inspections, lab analyses of indoor and outdoor mold spores and flood modeling to develop a comprehensive building-scale database for analyzing the connection between post-hurricane environmental factors and respiratory health. The database contained information for each building with a wide range of potential factors that affect respiratory health, including building properties, human indoor activities, indoor and outdoor mold and flood characteristics.

Why it matters

Although researchers have long known that mold leads to respiratory problems, this study presented a systematic examination of how conditions after flooding can exacerbate the growth of hazardous mold using a more detailed database than previous research.

 “Knowing the factors that are most likely to affect health gives us a guide for how to intervene before health problems begin,” said Professor Yassir AbdelRazig, a study co-author. “We know that resources for investment — for property owners and for outside agencies — are limited. This study gives a framework for what interventions can have the greatest impact.”

The research could help homeowners, health officials, insurance companies and emergency managers understand where health risks are greatest and develop strategies to minimize issues.

Future directions

Although the researchers examined conditions after hurricanes, the same problems can manifest after storms that don’t make headlines. Nuisance flooding, which doesn’t pose a threat to life or cause major property damage, can still lead to water intrusion at homes and prime conditions for mold growth.

Future research could add to the buildings surveyed, offering more robust analyses of the factors that affect respiratory health. A project using a control building without residents could examine the gradual effects of water intrusion over time and give researchers an understanding of how mold develops and affects indoor air quality, Ahmadisharaf said.

“Engineering has a major role to play in improving human health,” he said. “The indoor environments where we spend many hours of our lives are huge drivers of health. This research is about understanding that environment to help improve it.”

Doctoral alumna Maryam Pakdehi and doctoral student Ahmed Suliman were the lead author and co-author on this research, respectively. This study was supported by the National Science Foundation, the Danfoss Faculty and Graduate Student Fellows program, and an Early-Career Research Fellowship from the Gulf Research Program of the National Academies of Sciences, Engineering, and Medicine.