When Nina Flores first started analyzing emergency room data from New York City public housing, she was looking for a signal—proof that removing mold from homes could actually prevent asthma attacks. What she found was striking: nearly 2,800 fewer asthma-related emergency visits each year.
The story begins in 2013, when residents of NYC public housing filed a class-action lawsuit over mold that was triggering severe asthma. The New York City Housing Authority responded by creating Mold Busters, a comprehensive program that trained staff in evidence-based mold removal, overhauled ventilation systems, and cut response times for mold complaints. But while smaller studies suggested these fixes might help, nobody had proof at scale. That changed when Flores, then a doctoral student at Columbia University, compared emergency department visits between public housing residents served by Mold Busters and a control group of people living in nearby areas with similar income levels but no public housing intervention.
The numbers were clear: public housing residents averaged nine fewer asthma-related emergency visits per thousand people than their counterparts in comparable neighborhoods. This translates to nearly 2,800 fewer trips to the emergency department annually—a 25% reduction in what would have happened without the program. The research was presented at the ATS 2026 International Conference, marking the first large-scale observational study to demonstrate that citywide mold intervention can significantly reduce asthma exacerbations across an entire population.
What makes this particularly compelling is the dose-response relationship Flores found. Buildings where mold complaints dropped most sharply after remediation also saw the steepest declines in asthma-related emergency visits. The pattern is unmistakable: when you remove the trigger, you reduce the hospitalizations.
Yet even these impressive numbers likely underestimate the true impact. The study counted only emergency department visits—it did not capture the children who missed school because of breathing problems, the adults who lost work hours, or the countless nights of wheezing that never reached a hospital. Mold exposure triggers not just asthma exacerbations but allergic reactions and other respiratory illnesses. "The health benefits reported here likely underestimate the full scope of health-related benefits from the intervention," Flores explained.
Now at the University of Texas at Austin, Flores is pushing the research further. She and her team are planning to repeat the analysis as more data becomes available, asking whether the benefits hold steady or even grow over time. They're also conducting home visits among children in NYC public housing, measuring fungal exposure and allergic sensitization before and after mold removal. One hypothesis is particularly intriguing: mold removal might not just stop existing asthma from spiraling out of control—it could prevent new asthma cases from developing in the first place.
For public health officials watching housing and health intersect, Mold Busters offers a concrete example of what's possible when you treat the environment as a medical intervention. The residents of New York City public housing have already cast their verdict through their absence from emergency rooms.