Exploring Heat-Related 311 Service Requests as Indicators of Neighborhood Heat Burden in New York City

Heat is more than just a number on a thermometer; it is a physical force that presses against the walls of a city, testing the limits of its buildings, its power lines, and the people who live within them. In places like New York City, where concrete and asphalt trap warmth, extreme heat has become the leading weather-related cause of death. For decades, scientists and city planners have tried to map this danger using tools that look at the landscape from above. They measure the temperature of the ground from satellites and use census data to guess which neighborhoods might suffer the most, often relying on factors like how many trees are in a park or how many older adults live in a block. These maps are useful, but they tell a static story. They show where the heat is present, but they cannot easily capture how people actually feel it, how they struggle with it, or the specific ways they try to survive it when the temperature soars. To understand the true burden of heat, researchers needed a way to listen to the city itself as it reacts to the weather.

A team of researchers turned to a vast, everyday record of city life to find that missing piece of the puzzle: the 311 service request system. Every day, millions of New Yorkers call or click to report everything from potholes to noise complaints. These reports are not just administrative data; they are a form of social sensing, a way for residents to signal distress or need in real time. The researchers asked a simple but profound question: when a heatwave hits, do the types of complaints people file change in a way that reveals how the heat is affecting different neighborhoods? To find out, they gathered nearly 764,000 service requests from 2015 through 2025, focusing on days when the temperature stayed above 90 degrees Fahrenheit for three or more days in a row. They sifted through nine different categories of complaints, looking for patterns that would light up only when the city was baking.

The results revealed a clear and urgent signal. On days when the heat was extreme, the number of requests related to fire hydrants skyrocketed. On a normal day, the city receives an average of about 59 requests about hydrants, but on heatwave days, that number jumps to nearly 475. This surge represents a well-documented survival strategy where residents, particularly in areas without adequate air conditioning, open hydrants to create a cooling spray. Alongside this, requests for power outages more than doubled, rising from an average of 15 to nearly 40 per day, suggesting that the electrical grid was buckling under the strain of everyone trying to run their fans and air conditioners at once. A third category, ventilation complaints, also saw a significant increase, nearly doubling from 8 to 15 requests daily, pointing to a struggle with air circulation inside homes that are poorly ventilated or overheated. Other complaints, such as those about the smell of garbage or the need for new trees, did not show a consistent spike during these hot periods, confirming that the city's reaction to heat is specific and measurable.

When the researchers mapped these requests across the city's neighborhoods, a stark picture of inequality emerged. The areas with the highest rates of hydrant and power outage complaints were not scattered randomly; they clustered heavily in the Bronx and Upper Manhattan. These are neighborhoods that have long been identified as having higher poverty rates and fewer resources. The data showed that as a neighborhood's poverty level increased, so did the number of heat-related complaints. In the Bronx and parts of Manhattan, the combination of older housing stock, less green space, and a lack of cooling infrastructure meant that residents were more likely to rely on open hydrants or suffer from blackouts when the temperature rose. The study found that these patterns were not just about the weather; they were deeply tied to who lived there. For instance, the use of hydrants was most strongly linked to neighborhoods with a high share of Hispanic residents, while power outages were linked to a mix of poverty and racial demographics.

Perhaps the most revealing finding came when the researchers compared these service requests to actual health outcomes. They looked at emergency medical service dispatches for heat-related illnesses and found that the neighborhoods with the most ventilation complaints were the same ones sending the most people to the hospital for heat stress. This suggests that when residents complain about poor airflow or stuffy air in their homes, they are signaling a danger that is already translating into physical harm. In contrast, the locations of official cooling centers, such as libraries and community centers, did not align well with the areas reporting the most heat distress. The maps showed that these safe havens were often not where the people needed them most, leaving a gap between the city's planned response and the reality on the ground.

The study concludes that listening to the city through 311 requests offers a powerful new way to see heat inequality. While traditional maps can show where the sun is hottest, these service requests show where the heat is hardest to bear. They capture the difference between a neighborhood that is simply warm and one where the infrastructure is failing, where the power grid is breaking, and where residents are forced to improvise their own cooling solutions. By combining these real-time signals with standard weather data, city officials can move beyond guessing which neighborhoods are vulnerable and start targeting their resources—like fixing housing, upgrading the power grid, or opening more cooling centers—exactly where the residents are already asking for help. The data proves that the people living in the heat are already telling us where the problem is; the challenge now is to listen and act.