CDC/ATSDR Heat and Health Index Fact Sheet
The Heat and Health Index (HHI) is a tool to help identify communities where people are most likely to experience harmful effects from heat.
The Heat and Health Index (HHI) combines historical data on temperature, heat-related illness, pre-existing health conditions, sociodemographic factors, and natural and built environment factors into a single HHI ranking for each ZIP code nationwide. Public health officials, city planners, policymakers, and community members can use the HHI to identify and prioritize areas most likely to experience negative health outcomes from heat.
The HHI can help –
- Educate and inform the public about heat risk in their community,
- Identify and prioritize areas that may require special attention or additional action during the heat season to reduce heat-related illness over time, and
- Analyze the unique, local factors driving heat-related illness to inform research, policy, and decision-making.
The HHI consists of 25 data indicators of heat and health vulnerability to help communities prepare for warming temperatures in a changing climate. These indicators are grouped into 4 modules.
- The Historical Heat and Health Burden Module includes measures of previous experience with heat at the local level (ZIP code or Zip Code Tabulation Area).
- The Sensitivity Module includes pre-existing health conditions that may increase the risk of negative health outcomes when the individual with the condition is exposed to heat.
- The Sociodemographic Module includes social and demographic characteristics that increase exposure or sensitivity to heat or lessen one’s ability to cope with heat.
- The Natural and Built Environment Module includes characteristics of the natural and built environment that increase exposure or sensitivity to heat or lessen one’s ability to cope with heat.
The modules are combined into an overall ranking for each ZIP code. Individual module and indicator percentile rankings are also available, so users can make informed decisions to prepare for and prevent the negative health impacts from heat in their communities.
Data in the HHI come from the Centers for Disease Control and Prevention (CDC), the National Emergency Medical Services Information System (NEMSIS), the United States Census Bureau, the Multi- Resolution Land Characteristics Consortium (MRLC), and the Environmental Protection Agency (EPA).
The Heat & Health Index (HHI) is an effort led by the Geospatial Research, Analysis, and Services Program (GRASP). Explore the HHI at the NCEH Heat and Health Tracker. For more information about the HHI, see the HHI Technical Documentation or contact climatehealth@cdc.gov. For media inquiries, please contact envhealthmedia@cdc.gov.
Learn how place affects health at atsdr.cdc.gov/placeandhealth.