Data Visualization Lab — Milestone 2

Heat-Health
Risk Index

A composite index measuring how temperature amplifies pollution-related asthma risk across Los Angeles neighborhoods, combining environmental exposure and health vulnerability indicators.

Underlying Data

LA Neighborhood Risk Dataset

Source data drawn from CalEnviroScreen 4.0, NOAA temperature records, and LA County asthma ED visit rates. The Heat-Health Risk Index (HHRI) is a composite score (0–100) combining normalized values of each indicator.

Neighborhood Zip Avg Summer Temp (°F) PM2.5 (µg/m³) Asthma ED Rate
(per 10k)		 Tree Canopy (%) AC Access (%) HHRI Score Risk Level
Visualization 1 — Horizontal Bar Chart

Heat-Health Risk Index by Neighborhood

Composite HHRI scores ranked from highest to lowest risk. Scores are normalized 0–100. Color encodes risk tier, showing how inland and lower-income communities disproportionately bear heat-health burden.

Composite HHRI Score by Neighborhood
Higher score = greater combined heat, pollution, and asthma vulnerability
Extreme risk (≥75) Major risk (60–74) Moderate risk (45–59) Minor risk (25–44) No risk (<25)
HHRI scores range from 84 (Boyle Heights) to 18 (Pacific Palisades).
Key finding: Inland and lower-income neighborhoods like Boyle Heights, Watts, and Pacoima score 3–4× higher than coastal areas like Pacific Palisades and Santa Monica — reflecting compounding disadvantages in heat exposure, pollution burden, and asthma vulnerability.
Visualization 2 — Scatter Plot

PM2.5 Pollution vs. Asthma ED Rate

This scatter plot tests the core hypothesis: that pollution and asthma outcomes are positively correlated, and that temperature amplifies this effect. Bubble size represents average summer temperature — larger bubbles indicate hotter neighborhoods.

Pollution–Asthma Correlation, scaled by Heat Exposure
X-axis: PM2.5 concentration (µg/m³) · Y-axis: Asthma ED visits per 10,000 residents · Bubble size: avg summer temperature
Extreme risk Major risk Moderate risk Minor risk No/low risk Bubble size = temperature
Neighborhoods with higher PM2.5 levels show higher asthma ED rates. Hotter neighborhoods (larger bubbles) cluster in the upper-right, confirming that heat amplifies pollution health effects.
Key finding: A clear positive trend exists between PM2.5 and asthma ED rates. Critically, the largest bubbles (hottest neighborhoods) cluster in the upper-right quadrant — supporting the hypothesis that temperature amplifies the health effect of pollution.
Data & Method

Index Construction

The HHRI is a composite z-score combining three normalized pillars. Each indicator is scaled 0–100 before averaging, with temperature-pollution interaction weighted at 1.3× to reflect the amplification effect.

Pillar 1

Heat Exposure
Average summer (Jun–Sep) max temperature from NOAA GHCN-D stations + urban heat island adjustment by zip code.

Pillar 2

Environmental Burden
Annual mean PM2.5 from CalEnviroScreen 4.0, scaled by proximity to freeways and industrial sources.

Pillar 3

Health Vulnerability
Asthma ED visit rate (per 10k) from OSHPD; adjusted for age distribution and income-based access barriers.

Interaction Term

Heat × Pollution
Multiplicative interaction term (Temp × PM2.5) captures amplification effect. Weighted 1.3× in composite score.