Extreme Heat

Impacts of Extreme Heat

While temperatures are rising citywide, heat risk varies by neighborhood. As a result of systemic racism, lack of green space, limited access to air -conditioning, and poor housing quality, heat-exacerbated deaths are more common in neighborhoods that are home to a greater proportion of low-income and Black New Yorkers. And regardless of where they live, some individuals are more vulnerable to high heat:

• Older residents are at most risk because they are more likely to have underlying health conditions and be socially isolated or limited in mobility
• New Yorkers with mental illness are more vulnerable to extreme temperatures
• New Yorkers in homeless shelters or City jails are also more vulnerable, given that these facilities can lack proper air conditioning
• Workers in certain sectors of the economy are particularly exposed to heat risks: construction, transportation, utilities, and manufacturing. Many of these New Yorkers work outdoors or in facilities without adequate air conditioning and are subject to sweltering conditions

Besides the direct threat to public health, extreme heat can disrupt our infrastructure and impact how we get around in the city. Extreme heat strains the energy system. The electrical system has higher operating costs and a greater risk of localized outages during heat waves. On our streets and in our public spaces,road material can expand and asphalt can buckle during extreme heat events.

Meanwhile, residents that rely on the subway and other public transit systems could suffer during hot days. Walking and biking may be unsafe in extreme temperatures, particularly on streets and sidewalks without shade. Though many subway cars are cooled, subway platforms can reach dangerously high temperatures. The MTA requires trains to slow down during intense heat to protect rail lines. Critical communication infrastructure can also overheat. If there is a power outage due to extreme heat, sections of the transit network can stop running.

Areas Vulnerable to Extreme Heat

Differences in heat vulnerability across neighborhoods are rooted in social and economic disparities. These disparities stem from structural racism, which includes neighborhood disinvestment, and historical policies such as redlining. Central Brooklyn, Upper Manhattan, and the South Bronx, and many other parts of the City have the highest heat vulnerability.

The NYC Department of Health and Mental Hygiene (DOHMH) Heat Vulnerability Index (HVI) shows neighborhoods whose residents are more at risk for dying during and immediately following extreme heat. It uses a statistical model to summarize the most important social and environmental factors that contribute to neighborhood heat risk. The factors included in the HVI are surface temperature, green space, access to home air conditioning, and the percentage of residents who are low-income or non-Latinx Black.