The Heat-Health Risk Index maps how temperature, pollution, and underlying health vulnerabilities intersect across our neighborhoods.
Across Los Angeles, the "Urban Heat Island" effect means some neighborhoods are significantly hotter than others. When high temperatures overlap with poor air quality, the health risks don't just add up — they multiply.
This index visualizes data from 116 census tracts to reveal the correlation between high temperatures, pollution burdens, and asthma rates — so you can understand the full picture before choosing where to live.
Over 200 people die from heat in LA every year. Most live in neighborhoods that never knew they were high-risk. This index exists so that changes.
It's not just about one brutal afternoon. Chronic exposure to elevated temperatures — even just a few degrees above average — increases cardiovascular stress, worsens asthma, and accelerates dehydration, particularly for the elderly and children.
Neighborhoods with more tree canopy, lighter pavement, and newer housing stock stay significantly cooler. These benefits aren't randomly distributed — they follow historical patterns of investment and disinvestment across LA.
High temperatures accelerate the formation of ground-level ozone and other pollutants. In neighborhoods already burdened by traffic and industrial emissions, a hot day doesn't just feel worse — it measurably is worse for lung health.
When choosing where to live, people research schools, commute times, and rent prices. Almost nobody researches heat. This index puts that data where it belongs: in front of residents before they sign a lease.
Census tracts are small geographic units — typically 1,200–8,000 residents. Each dot or row in the data represents one tract. Use the map on the Data page to locate your neighborhood.
All scores are expressed as percentiles (0–100). A temperature percentile of 80 means that tract is hotter than 80% of all other tracts in the dataset — not that it's 80°F.
The final risk score combines temperature exposure, pollution burden, and asthma rate into a single weighted number. Higher scores indicate greater combined risk — not any single factor alone.
The most vulnerable tracts are those where all three factors — heat, pollution, and asthma — are simultaneously elevated. A tract that scores high in only one category carries far less risk than one high in all three.
Risk Score Guide
What the score ranges mean
The Heat-Health Risk Score is a composite of three percentile values. Use it as a relative signal, not an absolute diagnosis.
Explore three interactive views of the regional data. Hover any element for detail.
Ready to see how your neighborhood compares?
Explore Full Data Map