Human-induced climate change is increasing extreme precipitation events, potentially affecting respiratory health and healthcare access in urban areas. This study examined the relationship between precipitation-driven flooding events and emergency department (ED) visits for acute respiratory illnesses in New York City (NYC) communities.

We conducted a retrospective ecological study across 14 postal ZIP codes in New York City's five boroughs from October 2020 to November 2022. Using NYC Micronet sensor network data, we analyzed ED visits for influenza-like illness and pneumonia (n=53,534), categorizing flooding events as minor (<1.5 inches), moderate (1.5-2.5 inches), or major (>2.5 inches). Associations between flooding exposure and ED visits were analyzed using Poisson mixed effects models with a 6-day lag, controlling for socioeconomic status and COVID-19 rates.

Precipitation-driven flooding was associated with an average 2.8% decrease in respiratory ED visits after 6 days (IRR 0.972, 95% CI 0.955-0.989). Minor flooding showed a 2.4% reduction in visits, while moderate and major flooding were associated with 17.9% and 12.9% reductions, respectively. These associations remained significant after controlling for confounders.

Acute urban flooding events were associated with decreased respiratory ED visits, suggesting possible disruptions to healthcare access or deferred care. These findings affect climate change adaptation and infrastructure planning to ensure continued healthcare accessibility during extreme weather events.